A method for real-time implementation of HOG feature extraction
Author(s):
Hai-bo Luo;
Xin-rong Yu;
Hong-mei Liu;
Qing-hai Ding
Show Abstract
Histogram of oriented gradient (HOG) is an efficient feature extraction scheme, and HOG descriptors are feature
descriptors which is widely used in computer vision and image processing for the purpose of biometrics, target tracking,
automatic target detection(ATD) and automatic target recognition(ATR) etc. However, computation of HOG feature
extraction is unsuitable for hardware implementation since it includes complicated operations. In this paper, the optimal
design method and theory frame for real-time HOG feature extraction based on FPGA were proposed. The main
principle is as follows: firstly, the parallel gradient computing unit circuit based on parallel pipeline structure was
designed. Secondly, the calculation of arctangent and square root operation was simplified. Finally, a histogram generator
based on parallel pipeline structure was designed to calculate the histogram of each sub-region. Experimental results
showed that the HOG extraction can be implemented in a pixel period by these computing units.
Study on the temporal and spatial characteristics of high-speed turbulent flow field and its optical transmission effects
Author(s):
Cheng Chen;
Jindong Fei;
Shihe Yi;
Wenzhuo Tang
Show Abstract
When the aircraft flights in the earth's atmosphere with high speed, it will bring the aero-optical
effects into optical imaging detector system. These aero-optical propagation effects are caused by two parts: high-speed
turbulent flow field and aero-thermal window. This paper discusses the light propagation effects caused by high-speed
turbulent flow field. The high-speed turbulent flow field is a highly non-uniformly time-varying medium, which
possesses some characteristics depending on both time and space. While the light propagates through such a medium, the
imaging on target of detector system will be affected. This paper describes both the temporal and spatial characteristics
of high-speed turbulent flow field. To obtain the instantaneous distribution characteristics of turbulent flow field, one
method is applying NPLS-based measurement technique of supersonic flow field. The three-dimensional density field is
obtained by the relationship between density and image gray. We studied the physical phenomena of optical wave
propagating through turbulent flow field and then the caused optical distortion. The NPLS technique is a high-resolution
measurement method of the fine structure of supersonic three-dimensional complex flow field. The time resolution of
NPLS technique is 6 ns, and the time correlation resolution is 200 ns. These resolutions can satisfy the description of the
characteristics related to the time scale. We are able to describe the time correlation characteristics of density field using
NPLS image with different time intervals. Finally, the optical transmission effects of light, which propagates through
turbulent flow field, were simulated and studied. According to the instantaneous density field obtained from the NPLS
technique, it is carried out that the simulation of optical transmission effect of high-speed turbulent flow field at several
typical states. Then, using the ray-tracing method, the optical distance OPDi along the propagation path is obtained.
Shearlet-based hard-thresholding for interfered infrared image denoising
Author(s):
Ruibin Zou;
Caicheng Shi;
Erke Mao
Show Abstract
An infrared imaging device is effected by external electromagnetic interference(EMI), and images
appear salt and pepper noise (not excluded blind element and flash point of infrared focal plane arrays) and striping
noise. It causes an serious effect on the target detection and tracking. Median filter can not filter out the noise. It
urgently needs to resolve the problem. This paper presents a denoising method based on the shearlet transform, and
takes hard-thresholding method, to eliminate the infrared image denoising. Simulation results show that this
method effectively eliminates the noise, and retains the original image information. At the same time, in order to
show superiority, the method is compared with the median filtering denoising, db wavelet denoising, curvelet
denoising method in entropy, PSNR, LSCR and so on, which shows advantages.
An improved triangle star pattern recognition algorithm with high identification probability
Author(s):
Lei Du;
Yan Zhao
Show Abstract
In this paper, an improved triangle star pattern recognition algorithm is proposed. There are two improvements in the
algorithm compared with the classic triangle algorithm. Firstly, the adjacent measured stars in field of view are
eliminated and the remaining measured stars are used to build candidate measured star triangles. So high attitude
determination precision is obtained if a triangle is chosen from candidate measured star triangles to identify the three
stars. Secondly, in the candidate measured star triangles, the triangle which has great difference in three angular
distances is chosen as the measured star triangle waiting for identification, so as to mismatch between it and every guide
star triangle due to angular distance match can be avoided. In the case of a certain position and magnitude error limit,
simulation results indicate that the identification probability of this algorithm is much higher than that of the classic
triangle algorithm, and is also higher than that of the triangle algorithm based on the star pattern of two angular distances
and their angle. So the algorithm introduced in this paper can enhance the reliability of attitude determination of star
trackers.
Anomaly detection using background prediction in hyperspectral images
Author(s):
De-lian Liu;
Guo-jing He;
Jian-qi Zhang
Show Abstract
Anomaly detections in hyperspectral images are of great importance in a variety of applications such as military
reconnaissance, scene classification, and disaster evaluation, etc. Most interferences in anomaly detection are
generated by inhomogeneous background in practical applications. Therefore, many researchers resort to Gaussian
mixture model by classifying inhomogeneous background into numbers of homogenous regions. However,
the model might not perform well as anomalies presented locally. Thus, we propose a new anomaly detection
approach by introducing background prediction to suppress the interferences of background. Firstly, a conventional
background prediction model named two-dimensional least mean square (TDLMS) filter is applied on
each spectral image. Since anomalies have distinct spectral signatures from their surrounding background pixels,
they will be suppressed in the background prediction process. Next, a residual image is obtained by subtracting
the predicted background from the original hyperspectral image. And the background in original image will be
extremely eliminated while the anomalies are well preserved in the residual image. Finally, the conventional RX
algorithm is used to detect the anomalies in the residual image. We test the new algorithm via two real hyperspectral
subimages. The experimental results show that background prediction can suppress the interferences of
background effectively and improve the detection performance of the RX algorithm.
Design, fabrication, and characterization of quantum well infrared photoconductor in long-wavelength infrared
Author(s):
Ju-peng Jin;
Jian-xin Chen;
Chun Lin
Show Abstract
Optimum quantum well infrared photodetectors (QWIP) structure parameters such as well width and barrier height for a
given peak detection wavelength of 8 μm were designed, based on which GaAs/AlGaAs material with designed structure
was grown and single element QWIP devices were fabricated. In order to accurately calculate the optimum QWIP
structure parameters including well width, barrier height and doping density etc., we took into account higher order
effects such as band nonparabolicity in our calculations. One band effective mass approximation was employed in
modeling and shooting method was used in calculation. We fabricated three kinds of QWIP samples that have 20, 40
and 60 periods of quantum wells respectively. I-V characteristic curves and photoresponse at different temperature were
measured to characterize the detectors. A peak detectivity of 8×1010 cmHz1/2/W was demonstrated by one of our QWIP
devices. Besides, the varying performance of the three samples due to the different repeats of wells is discussed in this
paper.
Simulation of realistic infrared texture of aeolian sand ripples
Author(s):
Qian Liu;
Feng Zhu;
Xiao-wei Long;
Ying-ming Hao;
Shuang-fei Fu
Show Abstract
Texture is of vital importance when rendering realistic infrared images. Traditional attempts to simulate infrared
textures often suffer from insufficient realism seen in actual infrared images. This paper presents a synthesis model for
generating infrared texture of aeolian sand ripples. By integration of physical radiation model and texture structure
model, sources of variability that causes IR texture are modeled. The physical radiation model takes into account
geometrical, thermodynamic and meteorological parameters and calculates the thermal radiation distribution of different
surface slopes. The texture structure model is introduced based on natural landscape features to simulate spatial
distribution patterns of aeolian sand ripples. Simulation results are indicative of good performance of the proposed
method to simulate radiometrically-correct yet visually-appealing infrared textures.
A field transition particle filter tracking algorithm
Author(s):
De-jiang Xu;
Ze-lin Shi;
Xin-rong Yu;
Qing-hai Ding;
Hai-bo Luo
Show Abstract
Visual tracking is a critical task in many computer vision applications such as surveillance, vehicle tracking, and
motion analysis. The challenges in designing a robust visual tracking algorithm are caused by the presence of
background clutter, occlusion, and illumination changes. In this paper, we propose a visual tracking algorithm in a
particle filter framework to overcome these three challenging issues. Particle filter is an inference technique for
estimating the unknown motion state from a noisy collection of observations, so we employ particle filter to learn the
trajectory of a target. The proposed algorithm depends on the learned trajectory to predict the position of a target at a
new frame, and corrects the predication by a process that can be entitled field transition. At the beginning of the tracking
stage, a set of disturbance templates around the target template are accurately selected and defined as particles. During
tracking, a position of the tracked target is firstly predicted based on the learned motion state, and then we take the
normalized cross-correlation coefficient as a level to select the most suitable field transition parameters of the predicted
position from the corresponding parameters of the particles. After judging the target is not occluded, we apply the named
field transition with the selected parameters to compensate the predicted position to the accurate location of the target,
meanwhile, we make use of the calculated cross-correlation coefficient as a posterior knowledge to update the weights of
all the particles for the next prediction. In order to evaluate the performance of the proposed tracking algorithm, we test
the approach on challenging sequences involving heavy background clutter, severe occlusions, and drastic illumination
changes. Comparative experiments have demonstrated that this method makes a more significant improvement in
efficiency and accuracy than two previously proposed algorithms: the mean shift tracking algorithm (MS) and the
covariance tracking algorithm (CT).
The design research of a spinel dome
Author(s):
Hongwei Zhao;
Tianjin Hou;
Bin Zhu;
Qiu Huang;
Zhifeng Gao
Show Abstract
Based on the aerodynamic heating simulated results of a spinel middle-infrared (Mid IR) image
guide missile dome flying at supersonic speed, a series of experiments are made and some methods of
eliminating aero-heating effect are carried out successfully. First, a simulation experiment on the
ground discarding an outside protective shell of a spinel dome is accomplished in order to inspect the
withstanding impact ability of the dome. Second, an arc wind tunnel experiment is fulfilled to obtain
thermal mechanics characteristic of the spinel dome, and a method to buildup obviously mechanics
intensity is approved which is coating diamond protective layer on the external wall of the spinel dome.
Third, two heated dome imaging experiments on the ground are made to study the aero-optical
phenomenon. Finally, a rocket sled experiment of a guide missile head is made successfully.
Experimental results show that when the guide missile head flies in a supersonic, by adjusting the
frame integration time of detector etc. the aero-optic effect would decrease greatly.
The ship-borne infrared searching and tracking system based on the inertial platform
Author(s):
Yan Li;
Haibo Zhang
Show Abstract
As a result of the radar system got interferenced or in the state of half silent ,it can cause the guided
precision drop badly In the modern electronic warfare, therefore it can lead to the equipment depended on
electronic guidance cannot strike the incoming goals exactly. It will need to rely on optoelectronic devices to make
up for its shortcomings, but when interference is in the process of radar leading ,especially the electro-optical
equipment is influenced by the roll, pitch and yaw rotation ,it can affect the target appear outside of the field of
optoelectronic devices for a long time, so the infrared optoelectronic equipment can not exert the superiority, and
also it cannot get across weapon-control system "reverse bring" missile against incoming goals. So the
conventional ship-borne infrared system unable to track the target of incoming quickly , the ability of
optoelectronic rivalry declines heavily.Here we provide a brand new controlling algorithm for the semi-automatic
searching and infrared tracking based on inertial navigation platform. Now it is applying well in our XX infrared
optoelectronic searching and tracking system. The algorithm is mainly divided into two steps: The artificial mode
turns into auto-searching when the deviation of guide exceeds the current scene under the course of leading for
radar.When the threshold value of the image picked-up is satisfied by the contrast of the target in the searching
scene, the speed computed by using the CA model Least Square Method feeds back to the speed loop. And then
combine the infrared information to accomplish the closed-loop control of the infrared optoelectronic system
tracking. The algorithm is verified via experiment. Target capturing distance is 22.3 kilometers on the great lead
deviation by using the algorithm. But without using the algorithm the capturing distance declines 12 kilometers.
The algorithm advances the ability of infrared optoelectronic rivalry and declines the target capturing time by
using semi-automatic searching and reliable capturing-tracking, when the lead deviation of the radar is great.
The research of the coupling of circuit and chip
Author(s):
Yang Wang;
Honghui Yuan;
Qinfei Xu
Show Abstract
The paper mainly investigate the abnormal occurrence of no Photo current response at performance test of
detector after coupling of circuit and chip. At the beginning, we find that detector module is out of the way, while
preamplifier circuit and photosenstive chip operate well separately. Then we carry on various experiments such as
I-V measurement of chip, simulated magnification test of circuit, replace of high resistence chip, at various
background measurement and so on. All these experiments and theoretical calculation demonstrate that the large
background dark current resulting in the circuit's overload is the cause of detector's no Photo current response. By
means of adding optical filter and aperture slot to reduce the background radiation, consequently the reduction of
background dark current, and the detector finally works well without the circuit's overload.
Two-step local Wiener filter using dual-tree complex wavelet transform
Author(s):
Xiao-bo Zhang;
Xiang-chu Feng
Show Abstract
Amongst various image denoising methods, the Wiener filter is known to be a mean-square optimal linear estimator for
the true underlying image. The idea behind the Wiener filter frequently emerged in other image denoising algorithms. In
this paper, we present a new denoising scheme for the Wiener filter. The algorithm is carried out by two subsequent
steps. The output for the first step is used as the input for the second step. The ratio between the two step denoising
amounts plays an important role for good performance. The relationship between the proposed method and the heat
diffusion equation is established. The experiments show the proposed method outforms some of the denoising algorithm
published currently.
A new recurrent wavelet neural networks for adaptive equalization
Author(s):
Yi Sun;
Yang Chen;
Xiao-liang Luo;
Xiangli Lin;
Jin Lu
Show Abstract
A structure based on the recurrent wavelet neural networks(RWNNs) trained with unscented Kalman filter (UKF)
algorithm is proposed for the time-varying fading channel equalization in wireless communication system. Compared
with traditional neural networks based equalization, the main features of the proposed recurrent wavelet neural networks
equalization algorithm are fast convergence and good performance using relatively short training symbols, provided with
better performance of equalization. The simulation results for various time-varying channels are presented to show that
the proposed equalization algorithm is fit for Wavelet packet transform-based multicarrier modulation communication
system.
Study on image jamming effect of infrared imaging system induced by CO2 laser
Author(s):
Jinxi Che;
Dong Wang;
Hengwei Zhang;
Leilei Zhang;
Lei Zhang;
Zejun Dong
Show Abstract
In order to study the saturation threshold and the
image jamming effect of wavelength, energy or
power, frequency and size of laser spot, the laser
saturation jamming experiments by means of
diffuseness are developed, in which, CO2 tunable
pulse laser and CO2 continuous wave(CW) laser
separately interfere HgCdTe 288×4 cooled
scanning IR imaging system and microbolometer
poly-Si 320×240 Uncooled Focal Plane
Array(UFPA) staring IR imaging system. The
jamming effect is reflected through the
output-images of the IR imaging system. Therefore,
when the experiments were developing, with the
minishing of the laser beam attenuation, the energy
or power density of the laser was augmented.
Simultaneously, with the density of laser spot
changing, the changes of output-images had also
taken place. The output-images of the IR imaging
system were also observed, collected and saved.
Moreover, by adjusting the laser's energy density,
the saturation threshold was tested. Furthermore,
by adjusting the laser's energy or power density,
wavelength, frequency and size of laser spot, the
image jamming effect of IR imaging system
induced by CO2 laser was studied. In the
experiments of the size of laser spot's to jamming
effect, on the premise of the laser energy being
invariable, with the laser spot enlarging, on the
contribution to jamming effect, the added
interfered image elements compensate the loss to
jamming effect due to energy descending and
exceed it. In the experiments of the frequency to
jamming effect, when the jamming laser works
with higher repeating frequency, after the
interference is stopped, the resume time of IR
imaging system is more than it of laser working
with monopulse interference. Within settled time,
much impulses engender accumulation of energy
in detector, which correspond to improving the
laser's intensity at the jamming effect angle. So,
the jamming effect of IR image system is rightly
proportional to intensity of interference laser. And
improving jamming laser's frequency is propitious
to jamming effect of IR image system. In the
experiments of CO2 tunable pulse laser interfering
HgCdTe 288×4 cooled scanning IR imaging
system, the jamming effect of pulse laser is
unconspicuous. On the contrary, the CW laser's
jamming effect is conspicuous. This also have
something to do with the responding wave band of
IR imaging system. The all results are analyzed
through analyzing the jamming images, and they
show that the jamming effects are improved with
energy, frequency, wavelength and size of laser
spot increasing. Otherwise, the jamming effect
proves that the jamming means of diffuseness is
feasible.
Performance degradation of space Stirling cryocoolers due to gas contamination
Author(s):
Xin-guang Liu;
Yi-nong Wu;
Shao-hua Yang;
Xiao-ming Zhang;
Guo-hua Lu;
Li Zhang
Show Abstract
With extensive application of infrared detective techniques, Stirling cryocoolers, used as an active cooling source, have
been developed vigorously in China. After the cooler's cooling performance can satisfy the mission's request, its
reliability level is crucial for its application. Among all the possible failure mechanisms, gas contamination has been
found to be the most notorious cause of cooler's performance degradation by failure analyses. To analyze the
characteristic of gas contamination, some experiments were designed and carried out to quantitatively analyze the
relationship between failure and performance. Combined with the test results and the outgassing characteristic of
non-metal materials in the cryocooler, a degradation model of cooling performance was given by
T(t)=T0+A[1-exp(-t/B)] under some assumptions, where t is the running time, T is the Kelvin cooling temperature, and
T0, A, B are model parameters, which can be given by the least square method. Here T0 is the fitting initial cooling
temperature, A is the maximum range of performance degradation, and B is the time dependent constant of degradation.
But the model parameters vary when a cryocooler is running at different cooling temperature ranges, or it is treated by
different cleaning process. In order to verify the applicability of the degradation model, data fit analysis on eight groups
of cooler's lifetime test was carried out. The final work indicated this model fit well with the performance degradation of
space Stirling cryocoolers due to gas contamination and this model could be used to predict or evaluation the cooler's
lifetime. Gaseous contamination will not arouse severe performance degradation until the contaminants accumulate to a
certain amount, but it could be fatal when it works. So it is more serious to the coolers whose lifetime is more than
10,000 h. The measures taken to control or minimize its damage were discussed as well. To the long-life cryocooler,
internal materials must be baked and organic/epoxy materials should be used as few as possible. Further more, pipeline
for filling working fluid must have purifying facilities.
Fabrication and low temperature characteristics of InGaAs detector
Author(s):
Yanqiu Lv;
Qingduan Meng
Show Abstract
Planar InGaAs/InP p-i-n photodiodes have been successfully fabricated, and its spectral response, current-voltage
characteristic, photogenerated signal and noise were measured at 300 K and 77 K with the blackbody temperature fixed
at 900 K. It was found that the measured voltage signals reduced from 14.0 mV to 7.0 mV when the temperature
decreased from 300 K to 77 K. All measured results at 77 K show that the peak voltage responsivity of InGaAs detector
is Rvp= 2.41×107 V/W, and its peak detectivity Dp* = 1.51×1012 (cmHz)1/2/W. Measurement of transmittance spectral
indicated that the transmittance rate is over 80% at middle wavelength range. The results show that short wavelength
infrared InGaAs detector can be integrated with middle wavelength infrared detector to form dual-band detector worked
at liquid nitrogen temperature.
Research on method of infrared spectral imaging based on thermal imager
Author(s):
Ke-wei Huan;
Xiao-guang Shi;
Wei Wu;
Feng Zheng;
Xiao-xi Liu
Show Abstract
In recent years, technology of thermal imager and spectral imaging is becoming mature, and the application of them is
increased. The method is based on the blackbody radiation theory, make use of the infrared thermal imager to collect and
analysis the thermal images, distill the temperature value of different pixel of the thermal images, use Matlab to deal
blackbody radiation emitted curve fitting according with the temperature value of different pixels, and get the values of
the degree of radiation emitted at the same wavelength from the different pixels, then make spectral imaging (1μm~10μm) according to the values. At last, do analysis to spectral imaging of different spectral bands; discuss the limitations
of using this method to achieve spectral imaging.
Performance analysis of quantum dots infrared photodetector
Author(s):
Hongmei Liu;
Fangfang Zhang;
Jianqi Zhang;
Guojing He
Show Abstract
Performance analysis of the quantum dots infrared photodetector(QDIP), which can provide device designers with
theoretical guidance and experimental verification, arouses a wide interest and becomes a hot research topic in the recent
years. In the paper, in comparison with quantum well infrared photodetector(QWIP) characteristic, the performance of
QDIP is mainly discussed and summarized by analyzing the special properties of quantum dots material. To be specific,
the dark current density and the detectivity in the normalized incident phenomenon are obtained from Phillip
performance model, the carrier lifetime and the dark current of QDIP are studied by combing with the "photon
bottleneck" effect, and the detectivity of QDIP is theoretically derived from considering photoconduction gain under the
influence of the capture probability. From the experimental results, a conclusion is made that QDIP can not only receive
the normal incidence light, but also has the advantages of the long carrier life, the big photoconductive gain, the low dark
current and so on, and it further illustrates a anticipated superiority of QDIP in performance and a wide use of QDIP in
many engineering fields in the future.
Design of reimaging F/1.0 long-wavelength infrared optical system
Author(s):
Xin Zhang;
Bo Liu;
Hong-guang Jia
Show Abstract
A reimaging F/1.0 long-wavelength infrared optical system is proposed. The design has a flexible opto-mechanical
layout. The design process is as follows. Firstly, the catadioptric reimaging system consists of two reflecting mirrors and
a relay lenses. Two reflecting mirrors make up of the first imaging system and are therefore free of chromatic
aberrations, while low dispersion lenses were used in the reimaging system, so the optical system do not need achromatic
design for a high image quality. Then, to correct high-order aberrations resulting from large relative aperture, more
parameters need to be used with aspheric or diffractive surfaces due to modern optic technology development. Here,
aspheric is selected for easily manufacture. Finally, the design is completed with the help of ZEMAX software. The
effective focal length of the objective is 120mm and the field of view (FOV) is 4°. The simulated final design shows
adequate image quality and the modulation transfer function (MTF) is close to diffraction limit. The effect of the
surrounding environmental temperature is analyzed using the concept of thermal defocusing, and the thermal
compensation is discussed.
Numerical analysis and experimental research on active infrared thermographic NDT in composite materials
Author(s):
Cui-qin Wu;
Wei-ping Wang;
Qi-gang Yuan;
Yan-jun Li;
Wei Zhang;
Xiang-dong Zhang
Show Abstract
To estimate the disbond defects of the glass fiber composite materials applied in the solid rocket motor, active infrared
thermographic NDT is researched. Firstly, the numerical analysis of the transient thermal wave distubance under the
pulse heating stimulation is carried out using the finite element method. Then, the special experiment is arranged. The
specimen including 3 disbond defects with diameter 10mm, 20mm and 30mm is pulse heated using 2 symmetric pulse
heating sources, which the stimulation time is 2ms and the pulse energy is 4800J. The surface transient temperature is
monitored by the infrared camera system. Finally, The experimental results are compared with the ultrasonic C-scan.
Our research shows that the infrared thermography is a fast and effective inspection method for detecting defects of the
diameter over 10mm and depth within 5mm in the composite materials.
Research on multi-angle near infrared spectral-polarimetric characteristic for polluted water by spilled oil
Author(s):
Hui-yan Shen;
Pu-cheng Zhou;
Shao-ru Feng
Show Abstract
As the incidence of oil spills increases, the detection and measurement of oil pollution in the marine environment are
receiving augmented attention. Remote sensing is an increasingly important tool for the effective direction of oil spill
countermeasures. The most available physical quantities in optical remote sensing domain are the intensity and spectral
information obtained by visible or infrared sensors. However, besides the intensity and wavelength, polarization is
another primary physical quantity associated with an optical field. While the spectral information tells us about materials,
polarization information tells us about surface feature, shape, shading and roughness, and has the potential to enhance
many applications in optical remote sensing. During the course of reflecting light-wave, water-surface spilled oil will
cause polarimetric characteristic which is related to the nature of itself. Thus, detection of the polarization information
for polluted water by spilled oil has become a new remote sensing monitoring method. In this paper, four kinds of oils,
they are gasoline, diesel oil, motorcycle oil and soybean oil, were regarded as the experimental samples for polluted
water, and the multi-angle spectral-polarimetric instrument was used to obtain the multi-angle near infrared spectralpolarimetric
characteristic data of different oil-spilled water specimens. Then, the change rule between polarimetric
characteristic with different affecting factors, such as viewing zenith angle, incidence zenith angle of the light source,
relative azimuth angle as well as waveband of the detector were discussed, so as to provide a scientific basis for the
research on polarization remote sensing for polluted water by spilled oil.
Research on quantitative relationship between NIIRS and the probabilities of discrimination
Author(s):
Honggang Bai
Show Abstract
There are a large number of electro-optical (EO) and infrared (IR) sensors used on military platforms including ground
vehicle, low altitude air vehicle, high altitude air vehicle, and satellite systems. Ground vehicle and low-altitude air
vehicle (rotary and fixed-wing aircraft) sensors typically use the probabilities of discrimination (detection, recognition,
and identification) as design requirements and system performance indicators. High-altitude air vehicles and satellite
sensors have traditionally used the National Imagery Interpretation Rating Scale (NIIRS) performance measures for
guidance in design and measures of system performance. Recently, there has a large effort to make strategic sensor
information available to tactical forces or make the information of targets acquisition can be used by strategic systems. In
this paper, the two techniques about the probabilities of discrimination and NIIRS for sensor design are presented
separately. For the typical infrared remote sensor design parameters, the function of the probability of recognition and
NIIRS scale as the distance R is given to Standard NATO Target and M1Abrams two different size targets based on the
algorithm of predicting the field performance and NIIRS. For Standard NATO Target, M1Abrams, F-15, and B-52 four
different size targets, the conversion from NIIRS to the probabilities of discrimination are derived and calculated, and the
similarities and differences between NIIRS and the probabilities of discrimination are analyzed based on the result of
calculation. Comparisons with preliminary calculation results show that the conversion between NIIRS and the
probabilities of discrimination is probable although more validation experiments are needed.
The electrical characteristics of the HgInTe crystal and Pt/HgInTe Schottky contacts
Author(s):
X. L. Zhang;
W. G. Sun;
L. Zhang;
Z. X. Lu
Show Abstract
Photodiodes designed to be sensitive in the region 1.4~1.7μm and obtained by vacuum magnetron
sputtering of the Pt layer on the surface of the HgInTe single crystal are studied. Temperature dependence
on electrical characteristics of the crystal and the Schottky diodes were investigated in a temperature range
from 120K to260K. The current-voltage characteristics of the diodes show excellent rectification behavior.
Temperature dependence on the ideality factor and apparent barrier height was determined, including the
effect of series resistance. The evaluated ideality factor was observed to decrease from 2.93 to 1.42, while
the apparent barrier height is 0.563 in this temperature range. The temperature dependence of the forward
characteristics can be well explained by thermionic emission theory. The measured barrier height for Pt on
HgInTe is similar to the value reported for both ITO and Au rectifying contacts on this material. A possible
mechanism of the correlation of the ideality factor and barrier height has been proposed.
A cryogenic temperature eight-cell CMOS differential current amplifier for IR detectors
Author(s):
Honghui Yuan;
YongPing Chen;
ShiJun Chen;
Qiang Liu;
Xing Xu
Show Abstract
In order to make medium-long wave HgCdTe IR detector work normally it
must be in zero bias voltage, the differential input current preamplifier can easily make
HgCdTe IR detector biased at zero voltage. Because IR signals are often very weak, then little
disturb can affect the performance of the total detector system very much. In order to achieve
high Signal-to-Noise ratio, it is expected that the differential input current preamplifier can be
designed to work as close as to the HgCdTe IR detector. That is to say the preamplifier can
also work normally at 77K. In this paper, a high-performance low-noise differential input
current preamplifier working at cryogenic temperature for HgCdTe IR detectors is designed.
Since a differential input folded-cascode structure has been used in the preamplifier's design,
it makes that the gain of single stage amplifier can arrive 60dB, the circuit uses high resistant
poly as feedback resistance so that 40 MΩ feedback resistance can be integrated on chip at
temperature 77k ,which can directly transforms IR detector's current to voltage, avoiding the
additional noise by using exterior resister. The preamplifier's noise characteristics were
analyzed and the methods for decreasing noise were proposed. This differential input current
preamplifier was implemented in 0.5μm CMOS process. The size of eight-cell chip is
3mm×1.9mm. The test result shows that the current preamplifier has good performance at the
temperature of 77K. Within the bandwidth of 3.3KHz, the total output voltage noise is 120uV,
the equivalent total input noise voltage is 3PA, the equivalent input noise current is
0.03pA/Hz1/2@100Hz. The preamplifier power consumption is less than 1mW at 77K. When
the input current is less than 10nA, its linearity has been reached 99%. This circuit can work
normally at temperature between 300K to 77K and it can be used for several bands of IR
detector. Finally, it can work normally either by ±2 or by ±1.5 voltage power supply. This current preamplifier has been successfully applied in the signal readout of HgCdTe IR
detectors for infrared imaging.
Analysis on quantitative relationship between design parameters of infrared remote sensor and NIIRS
Author(s):
Yingji Jin;
Honggang Bai
Show Abstract
The National Imagery Interpretability Rating Scale (NIIRS) is a 10-level scale (0 to 9) of imagery interpretability, these
criteria indicate the level of information that can be extracted from an image of a given interpretability, the lowest is
Level 0 and the highest is Level 9. The General Image Quality Equation (GIQE) is a model that relates physical
parameters of an imaging sensor to NIIRS rating of the sensors image products. The scale has become an important tool
for defining image requirements, selecting and tasking imaging system. In this paper, we first introduce briefly NIIRS
and GIQE, and make an initial analysis about the factors affecting perceived interpretability of imagery, such as ground
sample distance(GSD), relative edge response(RER), height overshoot(H), noise gain(G), and signal-to-noise ratio(SNR).
Then, the design parameters of infrared remote sensor and GSD, RER, H, SNR, and NIIRS scale quantitative relation is
first determined, and the simulation curve of NIIRS scale versus R is presented. Finally, the analysis between NIIRS
scale and GSD, RER, H and G/SNR shows that it is evident that the GSD and RER are the dominant terms in the
equation, and that the overshoot H and the G/SNR have a much smaller impact. Comparisons with calculation results
show that the research can provide preliminary theory evidence for the optimum design of remote-sensors although more
validation experiments are needed.
Moving object detection based on segmentation of optical flow field in IR image sequence
Author(s):
Haifeng Lu;
Tianxu Zhang
Show Abstract
Detecting regions of moving objects between successive frames is of widespread interest. The accuracy of motion field
estimation strongly influences the performance of velocity field classification. An accurate optical flow estimation method
should be introduced. Furthermore, most existing approaches of motion field classification are complex, and their
performance depends on initialization parameters. In IR images, objects of interested usually appear as a slightly bright
spots, when compared to the background terrain. We first introduce an accurate gradient-based optical flow computation
method to estimate the motion filed which particularly suits the IR image sequence. Then a novel nonparametric and
automatic method for motion segmentation was developed. A simple and meaningful "threshold" is chosen to separate the
vector field into two classes. Meanwhile, the a priori entropies of motion field are defined, which the direction and
magnitude of motion vectors are taken into account at the same time. We use maximum entropy sum method, based on the
maximizing the information measure between two classes (object and background), to generate the optimal "threshold"
and classify velocity field. After ordinary morphology post-processing, our approach outputs regions of moving objects
and background from the scene. Experimental results demonstrate that our method is reasonable and performs well.
Noise research of microbolometer array under temperature environment
Author(s):
You-tang Gao;
Hua-min Chen;
Yuan Xu;
Xia-nan Sun;
Ben-kang Chang
Show Abstract
Thermal noise and steady performance of infrared sight has always been the concern of military production under
temperature test conditions. According to military optical instrument environmental test standard of GJB1788-93 and
MIL-STD-810F in infrared detector test method, the test procedure and test method of 320×240 α-Si micro-bolometer
array of UL01011-type were given in detail. By using thermal noise theory and mathematical model analysis method, the
noise models of Johnson noise, 1/ f noise, noise caused by electrothermal effect in temperature shock test condition, preamplifier noise and other noise models of micro-bolometer array were established and analyzed. Noise models
under temperature environment were analyzed. The results are as follows: the basic noise of micro-bolometer array is the
temperature fluctuating noise (thermal noise) which consists of background radiation fluctuation noise and thermal
conductivity noise. In addition, there is Johnson noise, 1/ f noise, noise caused by electrothermal effect and
preamplifier noise etc. Among them thermal noise, Johnson noise and 1/ f noise is the main noise source which
determines the limited performances of micro-bolometer array.
Optimal design of UAV's pod shape
Author(s):
Qun Wei;
Hong-guang Jia
Show Abstract
In the modern war, UAV(unmanned aircraft system) plays a more and more important role in the army.
UAVs always carry electrical-optical reconnaissance systems. These systems are used to accomplish
the missions of observing and reconnaissance the battlefield. For traditional UAV, the shape of the pod
on UAV is sphericity. In addition, the pod of UAV not only has the job of observing and reconnaissance
the battlefield, but its shape also has impact on the UAV's drag when it flies in the air. In this paper,
two different kinds of pod models are set up, one is the traditional sphericity model, the other is a new
model. Unstructured grid is used on the flow field. Using CFD(computational fluid dynamic) method,
the results of the drags of the different kinds of pod are got. The drag's relationship between the pod
and the UAV is obtained by comparing the results of simulations. After analyzing the results we can get:
when UAV flies at low speed(0.3Ma~0.7Ma), the drag's difference between the two kinds of pod is
little, the pod's drag takes a small part of the UAV's whole drag which is only about 14%. At transonic
speed(0.8Ma~1.2Ma), the drag's difference between these two kinds of pod is getting bigger and bigger
along with the speed goes higher. The traditional pod's drag is 1/3 of the UAV's whole drag value, but
for the new pod, it is only 1/5. At supersonic speed(1.3Ma~2.0Ma), the traditional pod's drag goes up
rapidly, but the new kind of pod's drag goes up slowly. This makes the difference between the two
kinds of UAVs' total drag comes greater. For example, at 2Ma, the total drag of new UAV is only 2/3 of
the traditional UAV. These results show: when the UAV flies at low speed, these two kinds of pod have
little difference in drag. But if it flies at supersonic speed, the pod has great impact on the UAV's total
drag, so the designer of UAV's pod should pay more attention on the out shape.
A theoretical structure calculation of MWIR HgCdTe e-APD
Author(s):
Ren-jie Gu;
Chuan Shen;
Lu Chen
Show Abstract
A theoretical calculation result of Hg1-xCdxTe (x=0.3) avalanche photodiodes (APDs) based on PIN structure is
obtained in the paper, which has a ratio of ionization factor k=0.06. The energy dispersion factor and the threshold
energy are acquired according to the parameters of material. And the gain, as well as the breakdown voltage, is obtained.
The composition, thickness, doping level is calculated theoretically to get an optimized APD device.
Evaluation of the operating range for ground-based infrared imaging tracking system
Author(s):
Bin Zhang;
Zhen-duo Zhang;
Shu-mei Zhang
Show Abstract
Ground-based infrared imaging tracking system (GIITS) is of great importance for aerial target
warning and guard. The operating range is one of the key performance specifications, which should be
calculated, analyzed and studied during the whole GIITS design process. The operating range is mostly
influenced by a few factors, including atmospheric attenuation, the performance of GIITS and feature of
target and background. This paper firstly makes analysis and summarization on the definite localizations of
the traditional operating range equation of the GIITS. The localizations are mainly in two aspects. On one
hand, the dispersion of the image and the effect of image dispersion are not considered in the traditional
method; on the other, calculate the radiation power received on the detector in order to analysis whether the
output signal meets the detection requirements or not, without considering the effect of the background
radiation. By improving of the traditional method, a new operating range calculation model of the GIITS
was established based on two requirements. One is that the image size of observed target should meet the
requirement of the processor signal extraction. The number of the pixel occupied by target image should be
more than 9. The other is that the signal noise ratio (SNR) of the GIITS should not be less than 5 to meet
the requirements of the target detection probability and spatial frequency. The SNR calculation equation in
form of energy is deduced and the radiation characteristic of the observed target and background are
analyzed. When evaluate the operating range of the GIITS using the new method, we should successively
calculate two operating range values according to two requirements mentioned above and choose the
minimum value as the analytic result. In the end, an evaluation of operating range for fighter aircraft is
accomplished as an example. The influence factors in every aspect on operating range were explored by the
calculated result. The new operating range calculation model provides the theoretical basis for the design
and applications as well as the comprehensive evaluation of a GIITS.
The algorithm of small and weak linear target detection
Author(s):
Zhen Han;
Hai-ou Zheng;
Yong Zhao;
Lin-xiang Guo
Show Abstract
In order to solve the problems which are the real-time is low and false alarm is high to the infrared detector system in
small and weak linear target. According to the detailed analysis of image formation system, the methods of the liner
characterized by rapid detection algorithms and the complex morphology character detection algorithm are bring up. It
can be used to test the small and weak linear target, and the algorithm processes and results are given. As one of the
assistant algorithms, these two algorithms are used in the infrared detector system, and the real-time of system and the
detection accuracy of target are improved obviously.
Infrared camera based on optical-readout bi-material FPA
Author(s):
Yan-mei Kong;
Rui-wen Liu;
Bin-bin Jiao;
Da-peng Chen
Show Abstract
With the trend of developments of infrared-focal plane array (FPA) which is particularly pronounced in many
applications, in this paper, we demonstrated an uncooled infrared (8~14μm) camera based on the optically read-out
Bi-material Infrared FPA. We reported on the fabrication and characterization of arrays of bimaterial microcantilevers.
On the basis of opto-mechanical effect and micro electromechanical system (MEMS) technology, a substrate-free FPA
with the thermal isolated structure SiNx and Au for uncooled infrared imaging is developed, with 49.5μm×49.5μm of the
pixel and 240×240 array, moreover, the camera had an average noise equivalent temperature difference (NETD) and a
response time of 100mK and 100ms at 7Pa atmospheric pressure, respectively.
The effect of flash power on the measurement of thermal effusivity using thermal wave imaging
Author(s):
Zhi Zeng;
Ning Tao;
Lichun Feng;
Yue Li;
Cunlin Zhang
Show Abstract
In aerospace applications, water or oil may ingress in the honeycomb structure, it is important to detect
what kind of liquid ingression it is. In this study, a 20mm thick steel plate was milled eight circular
holes (four 1.1mm depth and four 2mm depth) at the back side, each hole was filled with different
materials: water, oil, air and wax. Thermal wave imaging technology was successfully used in many
fields, such as aerospace, automobile, etc. quantitatively and qualitatively, it was used to measure the
thermal effusivity of filled materials in this study. A special experimental setup was adopted that the
steel sample was horizontally placed on a cover with holes faced above. The bottom surface of the
detected sample is heated with a short pulse of light, the sample surface is instantaneously heated to a
high temperature and captured by a high speed and high precision infrared camera. The generated heat
at front surface propagates to the interior of the sample, and leads to a continuous decrease of the
surface temperature. The theoretical model of temperature evolution with time was constructed, and the
calculation procedure of embedded material filled in steel holes was deduced based on the theoretical
model, and in which the air hole was used as the reference. In thermographic applications, different
power supplies, detection distance and infrared camera, etc. may result different signal levels, and
noise level may also vary which depends on the usage conditions of infrared camera. In this study, nine
different flash power levels, which changed from full scale power level to one ninth linearly, were used
to simulate different noise levels. The results of three different filled materials at nine different powers
and the corresponding error among different powers were compared. The calculation results indicate
that thermal wave imaging is a potential technology to test the thermal effusivity of an unknown
material when it is embedded in a known material.
High-throughput median filter for high-performance infrared imaging system
Author(s):
Xu Qin;
Yong Ma;
Hai Li;
Jun-feng Bo
Show Abstract
Many high-performance infrared imaging systems have been designed in recent years. This poses real-time challenges to
existing infrared image processing methods. Median filter is a nonlinear filtering technology widely used in infrared
imaging system to smooth image and correct missing pixels. Traditional median filter implementation is time-consuming
with long sorting cycle, which cannot meet the real-time processing requirement of high-performance infrared imaging
system. In this paper we present a new architecture for median filter. The proposed architecture optimizes the
comparators with pipeline design in order to enhance the processing velocity of sorting. Experimental evaluation and
comparisons show high efficiency of our design.
Discriminative region extraction and feature selection based on the combination of SURF and saliency
Author(s):
Li Deng;
Chunhong Wang;
Changhui Rao
Show Abstract
The objective of this paper is to provide a possible optimization on salient region algorithm, which is extensively used in
recognizing and learning object categories. Salient region algorithm owns the superiority of intra-class tolerance, global
score of features and automatically prominent scale selection under certain range. However, the major limitation behaves
on performance, and that is what we attempt to improve. By reducing the number of pixels involved in saliency
calculation, it can be accelerated. We use interest points detected by fast-Hessian, the detector of SURF, as the candidate
feature for saliency operation, rather than the whole set in image. This implementation is thereby called Saliency based
Optimization over SURF (SOSU for short). Experiment shows that bringing in of such a fast detector significantly
speeds up the algorithm. Meanwhile, Robustness of intra-class diversity ensures object recognition accuracy.
Dislocation cell structures in CdZnTe substrates and its behavior of threading into HgCdTe LPE epilayers
Author(s):
Xiaopan Cui;
Weizheng Fang;
Yanfeng Wei;
Chuanjie Zhang;
Hualian Xu;
Shiwen Sun;
Jianrong Yang
Show Abstract
Dislocation cell structures in CdZnTe substrates and its behavior of threading into HgCdTe LPE epilayers were studied.
A kind of dislocation cell structure of which dislocations linearly pile up to three <1 1 0> orientations on the (1 1 1) B
face of CdZnTe crystal was found. The formation of this cell structure can be demonstrated by the enrichment of the
dislocations through slip during the growth or cooling process. By comparing the dislocation densities and distributions
of HgCdTe LPE epilayers with it of CdZnTe substrates at the constant region using an optical microscopy system, the
behavior of cell structures of CdZnTe substrates threading into HgCdTe LPE epilayers were also discussed. The results
show that the stored dislocation densities at the dislocation walls can significantly affect the behavior of dislocation cell
structures threading into HgCdTe LPE epilayers. Dislocation cell structures of which dislocation walls have higher
stored dislocation densities can appear in constant region of HgCdTe epilayers. But the dislocations of HgCdTe epilayers
growth on CdZnTe substrate with lower stored dislocation densities at the dislocation walls are almost uniformly
distributed.
Comparison of two types of optical systems for space-borne staring IR sensors
Author(s):
Yan Li;
Guo-xian Zheng
Show Abstract
A proper type for the optical systems design is very important to the performance of a remote sensing or space-borne
surveillance system. In this work, two types of optical systems are designed and compared for space-borne staring IR
sensor systems which are mainly used for point-source detection and identification. The optical design is based on a staring
IR detector with 2K×2K array with 40μm pixel pitch, and capable of high frame rate imaging of multispectral bands from
SWIR to MWIR onto the same FPA. A rotating filter wheel is used for light splitting. Based on the given target parameters,
reflective designs are limited because of packaging limitations, then two types of refractive optical system are selected, one
type has intermediate image, and the other type has not. Different characteristics of the two types of optical systems,
including the size, the maximum aperture of lens, the F number, the MTF, and the encircled energy are compared.
Considering the best balance between size of the lenses, place of the filter wheel, imaging quality, the result of the
integrated comparisons is that the optical system with intermediate image is more suitable for this system. The advantage
of optical system with intermediate image is demonstrated in this application.
Design of infrared imaging system for inner-formation flying system
Author(s):
DaPeng Han;
Longlong Xiao;
Zhaokui Wang;
Kun Liu
Show Abstract
This paper describes an infrared Imaging system for the Inner-formation Flying System (IFS), a new kind of
spacecraft system to measure Earth's gravity field. Challenges arise when measuring the relative position between the
moving inner-satellite and its cavity. The observing process should be real-time and highly precise, with the premise that
non-gravitational disturbing force be restrained. An infrared imaging system was proposed for the observation.
Challenges were handled via a thermal-electronic-mechanical integration design. With a specially designed electronic
component, a dynamic thermal loop and a novel calibration mechanism, an infrared imaging system was established to
perform long-time continuous precise measurement. Infrared images with a Signal Noise Ratio better than 2:1 was
acquired, being sufficient to acquire accurate position of the inner-satellite. Performance of the imaging system was
validated by experiment.
Water spray parameters study with the minimum infrared transmission in the atmospheric windows
Author(s):
Zhong-wei Chen;
Chen Li;
Li Zhang;
Ling-jiang Zhang;
Hong-wei Chen
Show Abstract
Water spray is widely used in fire prevention and heat radiation protection due to its high infrared (IR) attenuation.
Recently, the calculation and theoretical analysis of water spray IR attenuation have been partially solved, where
multi-scattering in the water spray, distribution of droplets, concentration of droplets and water optical constant in the
infrared atmosphere windows are considered. However, is there a minimum for spectrum transmission of water spray in
the IR atmosphere windows band? If yes, what are the water spray parameters? These questions are still to be solved.
This article combines Lognormal Monte-Carlo Method (LNMCM) and Single Diameter Monte Carlo Method (SDMCM)
to calculate water spray infrared transmission. The droplet mean diameter is studied with SDMCM when the water spray
infrared transmission reaches the minimum. The geometric deviation of water spray is calculated with LNMCM at the
same conditions. The infrared transmission is calculated and analyzed with changing droplet diameters, on the stipulation
that total water content of air keeps unchanged. In this condition, droplet concentration increases with droplet diameter
decrease. Calculation results show that there is a minimum IR transmission of water spray in the atmospheric windows
band, which means there is a maximum IR attenuation. Infrared transmission of water spray reaches the minimum when
the droplet mean diameter is 12 micron and geometric deviation is less than 1.5. According to these, it is possible to
achieve maximum infrared attenuation with limited water supplied, as long as the spray nozzles parameters are in
accordance with the results.
Defects detection in crystalline silicon solar cells based on electroluminescence imaging
Author(s):
Xiao-yu Jiang;
Chao Wang;
Xi Wang;
Yan-tao Zong;
Chuang Pei
Show Abstract
In the use of crystalline silicon solar cells, the micro defects, such as cracks, the grain boundary dislocation, broken
metal grid fingers, etc., will seriously affect the efficiency and the life of crystalline silicon solar cells. Therefore, it is
necessary to detect the micro defects of Si solar cells rapidly and accurately in the production process. In this paper,
firstly, the relationship between the electroluminescence (EL) intensity from Si solar cells under the forward bias and
minority carrier diffusion length is simulated based on the calculation under the condition of ideal P-N junction model.
There exists one to one quantitative agreement. We find that the relationship referred above is nonlinear. Secondly, the
relationship between the defects in Si solar cells and minority carrier diffusion length (EL intensity) is summed up. The
defects and minority carrier lifetime are also in accord with this relationship. Based upon these, the micro defects in Si
solar cells could be made out in theory. With experiments, the defects in c-Si solar cells and poly-Si solar cells are
detected clearly from EI images. Theory analysis and experiments show that the method is reasonable and efficient.
A new design of ROIC with CDS and programmable arbitrary line selection
Author(s):
Pan Wang;
Rui-jun Ding;
Guo-qiang Chen;
Hong-lei Chen;
Li-chao Hao
Show Abstract
In this paper, a new design of readout integrated circuit application in short wave infrared is introduced.
An amplifier of one transistor is employed in the CTIA to reduce the area of the unit cell. The output
unit cell achieved CDS (correlated double sampling) and SH (sample and hold) is designed for public
use of a whole line, and is outside the array. A new digital control structure of IRFPA ROIC is
presented, with which the integral voltage of arbitrary contiguous or noncontiguous lines, rather than
regular lines, can be selected to readout. The structure of the circuitry and the operation principle are
analyzed, showing that the output dynamic range is over 2.5V, the cell capacity is more than 0.5Me- the
frame rate is 250Hz, and the linearity within working dynamic range is above 99.9 percent. This design
is going to be fabricated through Chartered 0.35um double-poly-four-metal (DPFM) process technique,
and the pixel occupies a 30um by 30um area.
A high performance readout circuit (ROIC) with BDI structure for SWIR FPAs
Author(s):
Li-chao Hao;
Rui-jun Ding;
Ai-bo Huang;
Hong-lei Chen;
Chun Zhou;
Pan Wang
Show Abstract
In our study, we designed a 512×512 readout integrated circuit (ROIC) for N-on-P short wave infrared
(SWIR) detectors, which has the ability to operate with two capacitors for different input current levels
from very low background applications to daytime high illumination conditions. A buffered direct
injection (BDI) readout cell as input circuit provides a low input resistance, high injection efficiency,
and precise biasing voltage to the photodiode at low input currents. In order to reduce the noise of the
BDI readout cell, a high-performance single stage amplifier is devised, the gain of which reaches as
high as 50dB. The input MOSFET of the amplifier operates at sub-threshold region to keep the
photodiode at precise reverse bias and steady injection efficiency. At the same time, with the input
MOSFET at sub-threshold region, the current is smaller than at saturation region, and the power
dissipation is reduced to a low level. A sample and hold circuit is also part of the input unit cell
architecture, which allows the infrared focal plane array (IRFPA) to be operated in full frame snapshot
mode and rolling mode. To prevent the excess of total current of the ROIC, the reset time of every row
has a lag of one period compared to the previous row. The simulation results confirm these advantages.
With the 5.0V power supply, ROIC provides the output dynamic range over 2.5V, the well capacity
more than 1×106e-, and the total power dissipation less than 120mW. The final chip is fabricated with
HHNEC 0.35um 1P4M process technology, and the pixel occupies a 30um×30um area. The Testing
results are coincide with the simulations of the circuit. With the detecting current varies from 30pA to
1nA, the linearity of BDI is 99%, and it can be operated at the temperatures below 77K.
An efficient method for infrared small target detection
Author(s):
Zhen-hua Su;
Dan-pei Zhao;
Jing Qi
Show Abstract
The efficient detection of small target in the low SNR image is an important and challenging research task in wide civil
and military applications. In this paper, we developed a novel and efficient infrared small target detection method based
on gray-scale morphology transform and higher-order statistics. Firstly, most of the image background regions are
removed using gray-scale morphology processing. Following by the background suppression, the method proposed in the
paper firstly uses higher-order statistics method to locate coarsely the region containing the target. Then, the paper uses
polynomial fitting to fit cumulative histogram of the region of interest after background suppression, and the optimal
adaptive segmentation threshold is obtained through the dynamic analysis of the slope of polynomial fitting curve. The
experimental results show that compared with the traditional detection methods, the proposed method is more effective
and faster for infrared small target detection.
The application of pulsed thermography in the inspection of wind turbine blades
Author(s):
Ning Tao;
Zhi Zeng;
Lichun Feng;
Xiaoli Li;
Yeshu Li;
Cunlin Zhang
Show Abstract
Wind power is a very promising source of environmentally safe, renewable, and the fast-growing
energy source over the past several years. The blades of a wind turbine are considered to be an
important component in wind turbine generator. Currently, bigger and more powerful wind blades are
being built to increase the swept area of the turbine and extract more energy from the wind.
Correspondingly, more capital cost is invested in manufacture and service. In order to reduce damage
possibility and extend the wind turbine blades life, there are increasing demands for the inspection of
wind turbine blades in the manufacturing factory and on site inspection. The regular inspections of
wind turbine blades are done normally by using visual inspection and tapping test. To improve the
safety of wind turbine blades, nondestructive testing technique using pulsed thermography is being
investigated in this study. This technique utilized an active pulsed heating source that is applied on the
outer surface of wind turbine blades, and an infrared camera to monitor the surface temperature
distribution controlled by a computer. Reflective pulsed thermography was directly applied on several
full scale wind blades, surface and subsurface defects, such as air bubbles, pin holes, edge bonding, etc.
were clearly detected. Several specimens were intentionally manufactured to simulate the glue faults
between supporting spars and glass fiber reinforced plastic (GFRP) shells with different thickness.
Afterwards they were inspected by using pulsed thermography in laboratory. The current test results
indicated that pulsed thermography has the potential for the detection of glue faults at least about
15mm thickness GFRP shell. It is shown that pulsed thermography maybe provide a powerful
non-contacting technique for the inspection of wind turbine blades as well in the workshop just after
the production or in the field that before and after installation of the wind blades and during reparation.
Mechanism and implementation of bidirectional IR scene simulation system based on the Peltier effect
Author(s):
Yun-song Feng;
Yuan Lu;
Jia Shen
Show Abstract
The IR scene simulation technique is an effective method to test the responsivity, the precision and the anti-interference
capability of the IR detector during its research and development; thus the technique may reduce the cost and research
time. Currently, the IR scene simulation technique based on MOS-Resistance arrays is one of the most popular IR scene
simulation techniques. However, resistance arrays can only be heated, but not refrigerated. Moreover, other simulation
techniques also have the problem of one-direction IR scene simulation. In this paper, the IR simulation mechanism is
studied in detail. According to the analysis of the characteristic of the semiconductor device based on the Peltier effect ,
the bidirectional IR scene simulation technique based on semiconductor refrigeration device with the Peltier effect and
the computer controlling technology is put forward. Moreover, a prototype machine is designed ,and the shortcoming of
the IR scene simulation system based on MOS-Resistance arrays which can only be heated is avoided. Finally, the
performance of the prototype machine is tested by experiments. The results show that the system can realize bidirectional
IR scene simulation perfectly by the means of increasing and reducing the temperature.
The LQG/LTR controller design for miniaturized infrared stabilizing platform
Author(s):
Renxin Xiao;
Tao Li;
Pinyi Zhang;
Xianguang Jia;
Ying Qin;
Chunqiao Xian
Show Abstract
In order to overcome the process disturbance and measurement noise brought by the low-cost miniaturized infrared
stabilizing platform, linear-quadratic-Gaussian with loop-transfer-recovery (LQG/LTR) theory is proposed for the design
of stabilizing controller to improve performance of the platform. The state-space model representing the dynamics of
stabilizing platform has been developed. Based on the model, state variables are estimated using Kalman-filter and then
the LQG controller is designed. LTR methodology is carried out to recovery the loop transfer of LQR and compensate
for the deficiency of worse stability robustness. The well-designed miniaturized infrared stabilizing platform is simulated
in both frequency-domain and time-domain. The results show that there are many required characteristics in the
stabilizing platform designed with the proposed method. It has good disturbance rejection and noise-free, which
enhances the stability robustness. It can acquire wide bandwidth that brings about the faster output response. On the basis
of the design it is convenient to implement the infrared tracking platform with zero steady-error.
IR line scanner on UAV
Author(s):
Shi-chao Liu;
Jie-xin Qin;
Hong-xing Qi;
Gong-hai Xiao
Show Abstract
This paper introduces the designing principle and method of the IR line scanner on UAV in three aspects of
optical-mechanical system, electronics system and processing software. It makes the system achieve good results in
practical application that there are many features in the system such as light weight, small size, low power assumption,
wide field of view, high instantaneous field of view, high noise equivalent temperature difference, wirelessly controlled and
so on. The entire system is designed as follows: Multi-element scanner is put into use for reducing the electrical noise
bandwidth, and then improving SNR; Square split aperture scanner is put into use for solving the image ratation distortion,
besides fit for large velocity to height ratio; DSP is put into use for non-uniformity correction and background nosie
subtraction, and then improving the imagery quality; SD card is put into use as image data storage media instead of the hard
disk; The image data is stored in SD card in FAT32 file system, easily playbacked by processing software on Windows and
Linux operating system; wireless transceiver module is put into use for wirelessly controlled.
The detection of chlorophyll content for salt stress of the wheat seedling by hyperspectral imaging
Author(s):
Qiong Wu;
Dazhou Zhu;
Cheng Wang;
Zhihong Ma;
Dongyan Zhang;
Kun Chen;
Jihua Wang
Show Abstract
An auto-development pushbroom imaging spectrometer (PIS) with wavelength range of 400-1000 nm was applied to
measure the chlorophyll content of wheat seedling. It showed that according to images of spectral imaging for leaves of
Chinese Spring (Salt-sensitive), Zhouyuan 9369(common and high-yield) and Changwu 134(salt-tolerant) wheat
seedling under salt stress, growth of salt-sensitive Chinese Spring wheat seedling was inhibited and it was feasible to
carry out qualitative analysis. Images could intuitively reflect morphological information of growth status of wheat
seedling and could show spectral differences of different leaves and different locations of one leave. Also, it was feasible
to identify green and yellow locations of leaf and to carry out qualitative analysis. The tested sites of spectrum and the
chlorophyll content measured sites were on the same area of single leaf. After measuring the hyperspectral image of leaf,
the mean reflectance spectra of each leaf was calculated Totally, 126 samples were collected, which were then divided
into a calibration set and a prediction set. Partial least square regression (PLSR) method was used to build the calibration
model. Results showed that the extracted hyperspectral spectra had high correlation with chlorophyll content. The
correlation coefficient of the calibration model is R=0.8138, the standard error of prediction is SEP=4.75. The results
indicated that hyperspectral imaging were suitable for the non-invasive detection of chlorophyll content of wheat
seedling.
Removing impulsive noise for infrared image with difference images and adaptive filter
Author(s):
Ju-feng Zhao;
Hua-jun Feng;
Zhi-hai Xu;
Qi Li
Show Abstract
In order to overcome the disadvantage of traditional median filtering method in removing impulsive noise, according to
the characteristics of impulsive noise image, a novel approach based on difference images and adaptive filter with
multiple windows is proposed. Firstly, utilize the noise image to obtain three difference images, while the difference
images are computing in three different directions which are level, vertical, diagonal (counterclockwise rotation of 45°
from the horizontal direction), and then get the position of impulse noise points by detecting these three difference image
with setting different threshold. Secondly, handle the detected impulse noise point using adaptive filter with multiple
windows. Finally, Peak Signal-to-Noise Ratio is used to assess ability of this approach in removing noise. Experimental
results indicate that when the, the effect of image restoration by this method can be increased by 8dB compared with
median filter. Advantage in removing noise but preserving detail is obvious compared with conventional median filtering
method.
As2/Ga flux ratios and low-temperature annealing dependence of Ga1-xMnxAs films by x-ray absorption spectroscopy
Author(s):
X. C. Cao;
G. S. Yao;
L. X. Zhang;
L. W. Wang;
Y. Q. Lv;
Z. Y. Peng
Show Abstract
We have measured room temperature x-ray absorption spectroscopy (XAS) at the Mn L2,3edges on ferromagnetic Ga1-xMnxAs films prepared under different As2/Ga flux ratios. A growth
condition relative energy shift (ΔE) at L2 peak was observed, the results suggest that the formation
of antiferromagnetic Mn-As complex under As-rich growth conditions and the energy shift can be
weakened even eliminated by post-growth low temperature (LT) annealing. The intensity of XAS
spectrum was promoted after post-growth annealing, and the effect of annealing was also
influenced by growth conditions.
Thermal imaging experiments of motor vehicles under low visibility at night
Author(s):
Xuan-yu Wang
Show Abstract
A low atmospheric visibility environment is artificially set up to test the thermal imaging characteristics of heave duty
truck, middle-sized truck and microbus under different visibilities and states by a thermal imaging system at night. By
the experimental results, all thermal images of various motor vehicles are very clear under high atmospheric visibility
whether the vehicle is started or not at night while the started motor vehicle is easier to distinguish from the environment
than the not started one. For started motor vehicles, the characteristic temperature is distributed at engine and tail gas
emission tube. The highest temperature appears on the surface of engine and it is greatly higher than other parts of the
motor vehicle. By the experiment, the average imaging temperature of motor vehicle body is hard to be affected by
visibility while the characteristic imaging temperature of engine is observably affected by low visibility. The lower the
visibility is, the more illegible the thermal image is. Especially, the highest imaging temperature decreases quickly and
falls toward the environment's temperature. Under very low visibility, the imaging temperature of character position is
still greatly higher than the average temperature of motor vehicle body or environment although the thermal image of the
whole motor vehicle body is illegible. As a result, any started motor vehicle may be found, scouted or traced by locking
the highest imaging temperature at engine part under low atmospheric visibility with a thermal imaging system.
Analysis to stray radiation of infrared detecting system
Author(s):
Jin-xing Niu;
Shuheng Shi;
Ren-kui Zhou
Show Abstract
In order to improve the detecting ability of dark target by infrared detecting system, stray radiation of the system should
be studied before and suppression methods should be adopted. In the infrared detecting system, thermal emission of a
room-temperature instrument may be several orders of magnitude larger than the flux of sources of target to be observed.
When baffles and vanes are designed to suppress the stray radiation coming from sources outside of the field of view of
the detecting system, their thermal radiation should be discussed together. In this article, the stray radiation of thermal
emission of infrared detecting system is studied. How to design baffles, vanes and stops is introduced. Their structure
models are established in TracePro. Their thermal emissions are simulated and analyzed by ray tracing program. The
number of photons on a pixel which emitted from suppression structure which varies from 260K to 310K is given by
simulation. From the simulation result, we can find that the stray radiation of thermal emission from inner baffle of
primary mirror is the predominant source; The stray radiation of thermal emission of system with vanes on main tube is
slightly bigger than that of the system with no vanes; the field stop placed at the first image plane can effectively
decrease the number of photons of stray radiation.
An FPGA-based heterogeneous image fusion system design method
Author(s):
Le Song;
Yu-chi Lin;
Yan-hua Chen;
Mei-rong Zhao
Show Abstract
Taking the advantages of FPGA's low cost and compact structure, an FPGA-based heterogeneous image fusion platform
is established in this study. Altera's Cyclone IV series FPGA is adopted as the core processor of the platform, and the
visible light CCD camera and infrared thermal imager are used as the image-capturing device in order to obtain dualchannel
heterogeneous video images. Tailor-made image fusion algorithms such as gray-scale weighted averaging,
maximum selection and minimum selection methods are analyzed and compared. VHDL language and the synchronous
design method are utilized to perform a reliable RTL-level description. Altera's Quartus II 9.0 software is applied to
simulate and implement the algorithm modules. The contrast experiments of various fusion algorithms show that,
preferably image quality of the heterogeneous image fusion can be obtained on top of the proposed system. The applied
range of the different fusion algorithms is also discussed.
Dim moving target detection method based on time-frequency analysis
Author(s):
Zhengzhou Li;
Lei Tian;
Wei Zheng;
Yuehua Zhang;
Gang Jin
Show Abstract
The signal-to-clutter ratio couldn't be improved effectively for conventional spatial or temporal high-pass filter is
difficult to remove clutter, especially clutter edge, and a dim moving target detection method based on the timefrequency
characters difference among target, noise and clutter is presented in this paper. Theoretical analysis shows that
the waveform at the target location in time-frequency domain is a small wave packet, the magnitude of the wave packet
is consistent with the target amplitude, and the width of the packet is inversely proportional to target speed; the
waveform at clutter edge is an "uphill" or "downhill". This target detection method takes two-stage filters to detect dim
target. At first, a threshold based on false alarm ratio criteria in the time-frequency is adopted to remove noise, and then
the ratio between "main lobe" and "side lobe" in the wave packet is counted to remove clutter and detect target. The dim
target detection experiment under cloud is included and the result shows that the method is effective.
Correlation recognition device based on spatial light modulator for infrared imaging system
Author(s):
Ye Wang
Show Abstract
In some special circumstances, some dynamic infrared target need to be detected and identificated on the static
background, This paper presents a correlation identification device based on spatial light modulator for infrared imaging
system, a 4F Fourier transform system added to infrared imaging system, The images captured by infrared camera is
loaded onto the input plane of 4Fsystem in real time using spatial light modulator, After a Fourier transform lens and the
digital image transform of its spectrum pattern, in this spectrum plane a special device is placed, and the device is
pre-proseecing through the background of the target then made into the matched filter, Thus, once again through another
Fourier transform lens to do the inverse Fourier transform, When there is a specific dynamic infrared target in the
background, the image loaded on the spatial light modulator will be different, the output plane will produce significantly
different output signal, Thus, in a very short period of time to complete the dynamic target recognition. This design can
transformed infrared image into coherent lignt information processing, it can improve recognition speed and reduce the
identification error, to do parallel multi-channel target recognition.
IR image synthesis for small target under sky background
Author(s):
Qi Cao;
Yong Shen;
Jun-feng An
Show Abstract
IR simulation about IR target and environment is one of the key technologies of semi-physical simulation in various IR
systems. The weapon system adopting IR imaging technology needs to test and estimate system's performance
frequently. A small target imaging module of IR detector is proposed. It's based on analyzing the imaging influence by
optic system, relative motion between target and detector, and atmospheric transmission. Combining the IR background
captured by camera and the small target image simulated by imaging module, a simulation of IR image under sky
background including the small target is carried out. The results show that the approach is fast and efficient. The
simulated image can verify proceeded detecting and tracking algorithms excellently.
Improved particle filtering algorithm based on the multi-feature fusion for small IR target tracking
Author(s):
Er-you Ji;
Guo-hua Gu;
Wei-xian Qian;
Lian-fa Bai;
Xiu-bao Sui
Show Abstract
A Mean-shift Particle filtering tracking algorithm based on the multi-feature fusion has been raised in this paper. This
algorithm mainly focus on the features of the high frequency histogram, fractal and the energy of the infrared small target,
which directly against the defects exist in detecting the infrared small targets, such as the size of the target, the low
tracking accuracy caused by the low SNR and so on. Since the particle filtering algorithm gives the advantage of
multi-feature fusion, the algorithm raised in this paper combines the three features listed above and does the calculation
using the particle weight to greatly improved the tracking accuracy. The clustering effect of the Mean-shift algorithm has
also been applied to make the distribution of the particles more equals to the real target, which reduced the number of the
particle and enhanced the real-time ability of the algorithm. The experimental results show that, this algorithm has better
tracking accuracy, which gives more effectiveness in tracking the infrared small target compared to the traditional
particle filtering algorithm.
The research and implementation of CFAR in infrared small target detection
Author(s):
Fu-yuan Xu;
Guo-hua Gu;
Weixian Qian
Show Abstract
Constant False Alarm Rate(CFAR) detection is a key technology in infrared small target detection and search. For
performance of CFAR is unstable and false alarm rate and detection rate are unpredictable when infrared small targets
are detected, this paper proposes a CFAR technique which based on background clutter distribution parameter estimation.
Through accurately estimation power of the local background clutter, the technology is able to select the appropriate
threshold. The system false alarm rate can be restrained in a certain constant by the threshold, so that the detection rate
and system performance can be improved. This paper introduces the estimating parameter methods and inspection
process of background clutter which is left after the infrared image under Robinson filter in details, and describes the
specific steps of the design of CFAR detector according to the different distribution models. The experimental data and
Analysis Results can fully show that this CFAR technique can suppress background clutter effectively, and improve the
detection rate under a certain false alarm rate.
Noninvasive blood glucose sensing on human body with near-infrared reflection spectroscopy
Author(s):
Zhen-hao Huang;
Chang-ning Hao;
Lin-lin Zhang;
Yan-chao Huang;
Yi-qin Shi;
Geng-ru Jiang;
Jun-li Duan
Show Abstract
The non-invasive blood glucose sensing method has shown its high impact on the clinic
application. This can make the measurement on the clinically relevant concentrations of glucose be
free from the pain of patient. The transmission spectrum study indicates that the dependence of
glucose concentration on the absorbance is in linear manner for the glucose concentration in the
region of 30mg/dL to 4.5×104mg/dL. By the near infrared reflection spectroscopy of fiber
spectrometer, the reflection band between 1.2μm and 1.35μm can be used to correlated with the
glucose concentration in the range of 30 to 300 mg/dL. This reflection band is finally used to
measure the glucose concentration effect in non-invasive manner, which gives the statistical
significance of P value 0.02. Our experiment result shows that it is possible to get the glucose
concentration by the near infrared reflection spectrum measurement on the human forefinger. This
non-invasive blood glucose sensing method may useful in clinic after more experiment for different
people.
A new registration method of infrared and visible images based on improved edge extraction and revised measure function
Author(s):
Jing Han;
Tao Huang;
Yi Zhang;
Lian-fa Bai
Show Abstract
An improved method based on traditional one of matching feature points is presented in order to realize the registration
of infrared image and visual image. In the improved method, firstly, image edges are extracted by the improved edge
extraction method and Harris operator is selected to detect feature points. The points prepared for matching are gained by
the AND operation between feature points and image edges. Thus the feature points not on the edges can be removed to
reduce false match rate and computation of matching feature points. Secondly, in the points prepared for matching, two
matching point pairs are extracted by the Revised Measure Function(RMF), then used to calculate registration
parameters of rigid transformation model for images registration. The method combines the advantages of features and
gray-based method, and has high registration accuracy. Experimental results show its feasibility and practicality, and it is
applicable to real-time visible and infrared images registration with any zoom scale, rotation angle and translational
quantity.
Design of antireflection film for underwater laser imaging system
Author(s):
Xiao-peng Zhang;
Jing-hua Sun
Show Abstract
In the underwater imaging system, When the light reflected from the surface of something tested through the water
medium gets to the surface of the imaging lens or when the light through the air gets to the surface of the imaging lens,
the reflection will happen, it leads that the light detectors receives the light less than before. The loss of light energy
leads to the decrease of image illumination. Meanwhile, some of the reflected light becomes of stray light to the surface
of image, and then that the contrast grade of image gets lower influences the quality of imaging. Hence, in order to
minimize the impact of image quality, a system for the underwater antireflection film to improve image quality should
be designed. This paper is based on the optical film-designed theory, for the blue-green light whose center wavelength is
532nm, the antireflection films of both air-optical glass interface and seawater-optical glass interface are designed, and
the reflectivity curve and the their calculated results are given.
Design of high ratio middle infrared continuous zoom optical system
Author(s):
Zheyuan Fan;
Jianzhong Cao;
Hongtao Yang;
Enshi Qu;
Dengshan Wu
Show Abstract
In recent years, the demand for infrared zoom systems is increasing in proportion with the development of infrared
technology and its applications. To meet this demand a variety of zoom lenses have been designed. Infrared cameras
operating in the 3-5μm spectral band are used in a wide variety of applications such as targeting, rescue, guidance and
surveillance systems as well as other equipment. This paper using cool 320×240 detector with staring focal plane array
and secondary imaging, a mid-wave optical system using mechanical-compensated with large-aperture and a zoom range
of 10:1 is designed. The Pixel Dimensions of the detector is 30μm, and the wavelength between 3.7μm ~4.8μm.The
system adopts negative group variable times and positive group of compensation which can realize 33mm~330mm
continuous zoom and FOV =20.61°~2.08° ,it consists of 7 lenses including 3 aspheric surface. The length of the system
is 262mm with the reflection mirror multipass optical path. The results show that the modulation transfer
function(MTF)are above 0.4 within the whole focal range at spatial frequency of 17 lp/mm, and Root Mean Square
(RMS) value of spot diameter were smaller than the Pixel Dimensions. After the image quality being optimized, the
narcissus analysis is done and 100% cold shield efficiency is obtained. Finallythe monotonic and smooth Cam curve is
given. The curve shows that the imaging plane is stable and the cam is easy to process. The system has advantages of
simple structure, high image quality and short zoom path etc.
Analysis and research on the thermal stress of detector affected by packaging accuracy
Author(s):
Linlai Fu
Show Abstract
Infrared focal plane detector has a multilayer configuration which consists of substrate, chip, readout IC, Indium
interconnects, epoxy and electrical lead board, it is packaged layer by layer precisely. Because of the difference in
thermal expansion between the layers, with repeated thermal cycling plenty of thermal stress produced by assembling
errors will lead result in failure of the interconnects or lead to damage to the detector pixels. In this paper, based on a
detector-Dewar assembly, we analyze the thermal stress on the detector by different packaging accuracy level. With the
allowable thermal stress, we optimize the processes of the packaging experiment and redesign the fixtures used in the
packaging processes to improve assembly accuracy, on this condition, the detector-Dewar assembly assembled satisfies
our design requirement, and the thermal stress caused by the cooler is below the range permitted.
The technology of generating infrared image based on electric heating film technology
Author(s):
Yuan Lu;
Yun-song Feng;
Ya Qiao
Show Abstract
The technology of generating infrared image based on electric heating film technology by its resistance per unit area was
studied. A Lifgt-off-road vehicle was used as an object to be simulated. An infrared thermograph was used to
photography the light-off-road vehicle from a specific corner. As a result several infrared images of the light-off-road
vehicle were obtained and the thermal distribution of the vehicle was also obtained at the same time. A matlab program
was used to process the image. The image was divided into several areas according to its grey level. Each area has its
own temperature range. The average temperature of each area was calculated. A thermal balance equation was
established according to the average temperature of each area and the environment temperature. By solving these
equations, the radiant existances of these areas were gotten. The heating power per unit area of these areas was
calculated. The electric heating film was preparation accordingly. The power was applied on the film and the infrared
thermograph was used to observe it. The infrared image of the film has a high similarity with the true light-off-road
vehicle's.
Design of catadioptric middle infrared continuous zoom lens for uncooled infrared detector
Author(s):
Kai Jiang;
Si-zhong Zhou;
Jing Duan;
Yan-bin Wang;
Heng-jin Zhang
Show Abstract
For uncooled 320×240 infrared detector, a catadioptric middle infrared continuous zoom lens is presented. The optical
system is divided into three segments. First of all, a reflective system is designed as the front system. Then the
continuous zoom lens which matches with the reflective system as the back system is designed. The conversed back
system is assembled at the first imaging of the optical system with the reflective system. A continuous variable
magnification catadiootric telescope is obtained. Projection objective is designed based on the telescope lastly. To ensure
the imaging quality of the system, the whole system is optimized with the CODE V software. The system can realize
200mm~800mm continuous zoom. The designed result shows the system has the advantages of simple structure, short
zoom path and smooth zoom locus, high image quality and approached or reached to the diffraction limit.
A millimeter wave image fusion algorithm design and optimization based on CDF97 wavelet transform
Author(s):
Jian-cheng Yu;
Bo-yang Chen;
A-lin Xia;
Xin-guang Liu
Show Abstract
Millimeter wave imaging technology provides a new detection method for security, fast and
safe. But the wave of the images is its own shortcomings, such as noise and low sensitivity.
Systems used for security, since only the corresponding specific objects to retain the information,
and other information missing, so the actual image is difficult to locate in the millimeter wave .
Image fusion approach can be used to effectively solve this problem. People usually use visible
and millimeter-wave image fusion. The use of visible image contains the visual information. The
fused image can be more convenient site for the detection of concealed weapons and to provide
accurate positioning. The integration of information from different detectors, and there are
different between the two levels of signal to noise ratio and pixel resolution, so traditional
pixel-level fusion methods often cannot satisfy the fusion. Many experts and scholars apply
wavelet transform approach to deal with some remote sensing image fusion, and the performance
has been greatly improved. Due to these wavelet transform algorithm with complexity and large
amount of computation, many algorithms are still in research stage.
In order to improve the fusion performance and gain the real-time image fusion, an Integer
Wavelet Transform CDF97 based with regional energy enhancement fusion algorithm is proposed
in this paper. First, this paper studies of choice of wavelet operator. The paper invites several
characteristics to evaluate the performance of wavelet operator used in image fusion. Results show
that CDF97 wavelet fusion performance is better than traditional wavelet wavelets such as db
wavelet, the vanishing moment longer the better. CDF97 wavelet has good energy concentration
characteristic. The low frequency region of the transformed image contains almost the whole
image energy.
The target in millimeter wave image often has the low-pass characteristics and with a higher
energy compare to the ambient region. Based on this assumption, a new fusion rule is proposed here. Firstly, get the low-frequency part of the selection matrix according to the comparison
regional low-frequency energy matrix of the two images. Then, taking into account the
consistency and continuity of low-frequency detail, high frequency and low frequency selection
matrix can be the same. And this can ensure a better fusion of the edge of the image
characteristics. Simulation results show that this algorithm's performance is much better compared
to traditional energy-weighted and average method, though less quantitative comparison point
compared to the region based method, yet, the difference is small according to the visible
evaluation.
This algorithm is tested in the self-developed image processing platform based on DM642. By
using the optimization strategy, the speed of 256 × 256 dual-channel image fusion can be more
than 28 F/S. Therefore, the proposed fusion algorithm can meet the system performance and
application requirements.
Jamming efficiency evaluation of the IR smoke screen against high-orbit IR detector
Author(s):
Gui-qing Gao;
Yong-xiang Li
Show Abstract
In order to lower the orientating capability of the DSP satellite, at first the paper analyzes early warning
missile satellite detective system, introduces the jamming mechanism of infrared smoke screen, and a model of jamming
efficiency evaluation of the IR smoke screen against early warning satellite was built from three sides of absorbency of
smoke screen to infrared radiation, dispersion ability and infrared radiation from smoke screen self. At last the correlative
conclusion was got based on the brief depiction of Early-warning Satellite.
Strain-compensated InP-based InGaAsInAlAs quantum cascade infrared detectors for 3-5μm atmospheric window
Author(s):
Shen-qiang Zhai;
Jun-qi Liu;
Ning Kong;
Feng-qi Liu;
Lu Li;
Li-jun Wang;
Zhan-guo Wang
Show Abstract
Infrared detection within the atmospheric window between 3 to 5μm has gained great interest because of its wide range
of applications, such as eye-safe free-space optical communication links and high-precision time-of-flight measurements
used in 3D imaging. In this letter, we report on the characteristics of two InP-based strain-compensated InGaAs/InAlAs
quantum cascade detectors (QCDs) detecting around 4 μm and 4.5 μm, which are promising candidates for applications
in this wavelength range. Maximal responsivity values of 11.43mA/W at 180K and 10.1 mA/W at 78K and Johnson
noise limited detectivities of 2.43×1010 and 2×1010 Jones at 78K, for the 4.5 μm and the 4 μm device, respectively, were
obtained. In addition, both devices can work up to room temperature with responsivities of 0.81 mA/W(4.5μm) and 1.64
mA/W(4μm).
The background suppression algorithm based on the two-dimensional velocity vector histogram and the estimated risk
Author(s):
Jian Qin;
Qian Chen;
Weixian Qian
Show Abstract
The small-target detection in infrared image is a difficult task in remote sensing fields. First of all, the reason of the
increased false alarm rate under the cloud cluster background is analyzed. In order to avoid this kind of the false alarm,
the background suppression algorithm based on the two-dimensional velocity vector histogram and the estimated risk is
presented. The image sequence is filtered firstly under the higher false alarm rate to extract the further more interference
points in the cloud region. Then the velocity vectors of all the detected points including the interference points are
computed by the means of date association. And the two-dimensional velocity vector histogram is calculated with the
velocity vector of all the detected points. It is found that the most of the detected points are the interference points in the
cloud and the velocity and the direction of the cloud are identical in a certain field of view for some time. According to
the characteristic of the cloud, the range of the cloud velocity vector is obtained based on the velocity vector histogram
by means of the statistics. The false alarm points in the motional cloud are filtered out according to the velocity range.
But a few false alarm points in the cloud may also exit. So the concept of estimated risk is presented to evaluate the
possibility of false alarm point. The threshold of each part of the image is adaptively adjusted based the estimated risk
evaluated by the complex level of background. Then the false alarm points in the complex cloud are filtered out based
the threshold. The experimental results with the real image show that the proposed method can reduce the false alarm of
the target detection under the cloud background and detect target successfully.
BP network identification technology of infrared polarization based on fuzzy c-means clustering
Author(s):
Haifang Zeng;
Guohua Gu;
Weiji He;
Qian Chen;
Wei Yang
Show Abstract
Infrared detection system is frequently employed on surveillance operations and reconnaissance mission to detect
particular targets of interest in both civilian and military communities. By incorporating the polarization of light as
supplementary information, the target discrimination performance could be enhanced. So this paper proposed an infrared
target identification method which is based on fuzzy theory and neural network with polarization properties of targets.
The paper utilizes polarization degree and light intensity to advance the unsupervised KFCM (kernel fuzzy
C-Means) clustering method. And establish different material pol1arization properties database. In the built network, the
system can feedback output corresponding material types of probability distribution toward any input polarized degree
such as 10° 15°, 20°, 25°, 30°. KFCM, which has stronger robustness and accuracy than FCM, introduces kernel idea
and gives the noise points and invalid value different but intuitively reasonable weights. Because of differences in
characterization of material properties, there will be some conflicts in classification results. And D - S evidence theory
was used in the combination of the polarization and intensity information. Related results show KFCM clustering
precision and operation rate are higher than that of the FCM clustering method. The artificial neural network method
realizes material identification, which reasonable solved the problems of complexity in environmental information of
infrared polarization, and improperness of background knowledge and inference rule. This method of polarization
identification is fast in speed, good in self-adaption and high in resolution.
Investigation on the optical properties of sulfur-doped diamond thin films
Author(s):
Yongjie Wang;
Qingxun Zhao;
Zengqian Yin;
Zhanlong Zhao
Show Abstract
Sulfur-doped diamond thin films have been synthesized using CH4/H2/Ar/H2S gas mixture by hot filament chemical
vapor deposition (HFCVD) technique. The optical properties of the films are investigated by SEM and Raman spectra.
The Gaussian line shape is used in the curve fitting for the Raman spectra. Results show that the ID/IG presents the trend
of first increase and then decrease with the increase of S/C ratio, however, an upward shift of the diamond peak is
observed. This implies residual stress in the sulfur-doped diamond thin films. Moreover, optimum experimental
conditions are proposed.
Detection of IR target by fusing multispectral IR data
Author(s):
Liya Li;
Meng Qi;
Xuhui Gao
Show Abstract
Detection of the small target in clutter, usually regarded as singular points in the infrared image, is an important issue
in infrared searching and tracking (IRST) system. Because of the far range of the target to the sensor, the stealth
technology, the effects of inherent sensor noise and the phenomena of nature, the target is more difficult to be detected.
Multispectral sensor system has been proved it could greatly improve detection of the small, hard-to-find targets by
multispectral processing techniques (such as sensor or image fusion). Aiming at the problem of multispectral IR Target
Detection, a kind method of the multispectral IR target detection is proposed, based on the existed detection systems. In
this method, the image registration is done firstly to make the different sensors have a same scene. Then, a fusion rule,
named as adaptive weighted voting theory, is developed to combine the target detection results from the different spectral
sensors. The adaptive weighted voting theory can give the different weights, based on the different spectral IR
characteristics, and these weights decide the detected target is identified as real target or background. The experimental
results show that the proposed method can reduce the detection uncertainty and improve the detection performance.
Compared with the single spectral detection results and the others fusion detection methods, it can decrease the lost
alarm rate and the false alarm rate effectively. The proposed method has been employed in our IR surveillance system,
and it is easy to be used in the various circumstances.
Study on reliability enhancement testing for InSb focal plane array detector
Author(s):
Meng Chao;
Peng Jing;
Ma Wei
Show Abstract
InSb focal plane array (FPA) detectors which are important components of infrared systems have great influence on
systems' reliability and development. Few researches have been focused on this field in recent years. Therefore, it is
rather essential to carry out reliability test. In the paper, reliability enhancement testing has been carried out on 128×128
elements InSb FPA detectors to discuss the influence of temperature stresses and vibration stresses on structure and
performance. Working boundary conditions of InSb FPA detectors were obtained. Aiming at the failure the corresponding
improvements were adopted, and reliability of detector was enhanced greatly.
The accelerated vacuum life test research of Dewar
Author(s):
Yani Zhang;
Xiaokun Wang;
Sangen Zhu;
Haimei Gong
Show Abstract
The Dewar package is one important way for infrared focal plane detector's application.
Vacuum life is one of pivotal technologic parameter for infrared detector Dewar assembly. It is
important to estimate the vacuum life of Dewar in room temperature fleetly and truly. The
accelerated vacuum life test is a good way to shorten test time. The statistical and analytical way of
test data to estimate distribution of Dewar vacuum life that is confirmed. Through test accelerated
factor, vacuum life of Dewar in room temperature can be gained.
A wavelet-based adaptive fusion algorithm of infrared polarization imaging
Author(s):
Wei Yang;
Guohua Gu;
Qian Chen;
Haifang Zeng
Show Abstract
The purpose of infrared polarization image is to highlight man-made target from a complex natural background. For
the infrared polarization images can significantly distinguish target from background with different features, this paper
presents a wavelet-based infrared polarization image fusion algorithm. The method is mainly for image processing of
high-frequency signal portion, as for the low frequency signal, the original weighted average method has been applied.
High-frequency part is processed as follows: first, the source image of the high frequency information has been extracted
by way of wavelet transform, then signal strength of 3*3 window area has been calculated, making the regional signal
intensity ration of source image as a matching measurement. Extraction method and decision mode of the details are
determined by the decision making module. Image fusion effect is closely related to the setting threshold of decision
making module. Compared to the commonly used experiment way, quadratic interpolation optimization algorithm is
proposed in this paper to obtain threshold. Set the endpoints and midpoint of the threshold searching interval as initial
interpolation nodes, and compute the minimum quadratic interpolation function. The best threshold can be obtained by
comparing the minimum quadratic interpolation function. A series of image quality evaluation results show this method
has got improvement in fusion effect; moreover, it is not only effective for some individual image, but also for a large
number of images.
Research on portable intelligent monitoring system based on video server
Author(s):
Gui-cai Song;
Yan-xiang Na;
Fei-yu Yang;
Shi-hao Cao
Show Abstract
Intelligent video surveillance system study in this paper is constituted by CCD cameras, infrared pyroelectric sensor,
stepping motor and the computer. And make In-depth study for portable intelligent monitoring system from two aspects
of hardware and software. compare and analyse between CCD image sensor and CMOS image sensor, key research on
the CCD various' characteristics and performance indicators; investigate for the infrared pyroelectric sensor structure,
characteristics, put forward further method to improve pyroelectric sensor performance, response degree. On software,
according to the calculation of moving object detection, through controll the step motor, can tracking video real-time or
finish videoing,video Real-time. Intelligent video surveillance system use infrared pyroelectric sensor as access switches,
make sure the foolproof of monitoring site safety system.
Enhancement algorithm for real-time infrared image processing
Author(s):
Tian Si;
Lizhi Wang;
Yijia Tian;
Junju Zhang
Show Abstract
A new real-time infrared image enhancement algorithm which applies to FPGA is proposed in this paper. In real-time
infrared image processing, image's contrast is very low, the noise of the regular graph is effects of real-time infrared
image system precision primary factors, Seems particularly important how about to reduce infrared image noise and
improve the precision at the infrared image. In order to reduce infrared image noise, we use adaptive piecewise linear
transformation algorithm for infrared image enhancement, and objective evaluation of the enhanced images, at the same
time also to discuss real-time of the algorithm, and verify the feasibility of applying this algorithm.
Analyzing the CO2 column amount in China with GOSAT data
Author(s):
Cai-lan Gong;
Ying Zhou;
Yong Hu
Show Abstract
Global climate change has brought about many environmental problems. It was considered that the increase of green
house gases should be responsible for that, especially carbon dioxide (CO2). There are some in-situ observation stations
distributed in the world-wide, but it's not enough to perform the global atmospheric variation laws for the sparse
observation points with non-uniform distribution. The Greenhouse Gases Observing Satellite (GOSAT) is the world's
first spacecraft to measure the concentrations of carbon dioxide and methane from space. It has finished CO2 global
distribution maps on internet, but there is little study on the regional CO2 distribution with higher spatial resolution,
especially about the metropolitan CO2 distribution. The CO2 column amount were analyzed in the Yangtze River delta
area that indicted it varied with the seasons. In order to explain the CO2 distribution differences, the land surface
temperature (LST) and the Normalized Differential Vegetation Index (NDVI) were analyzed from the China
Huanjing-1A (HJ-1A) and Huanjing-1B (HJ-1B) satellite data. The results showed that there were some correlations
between the land surface characteristics and the CO2 column amount. It appeared that the CO2 column amount retrieved
from the SWIR band of FTS reflected the near surface atmospheric contents were affected obviously by the human
activities. More verification experiments with in-situ observation data should be conducted. The study results could be
benefit for improving the accuracy of CO2 flux estimation from the satellite data, and it's useful for the studying the
correlations between the climate change and the economic development.
Research on bad pixel variation of IRFPA by high temperature storage and temperature shock
Author(s):
Wei Wang;
Yang-yu Fan;
Yue-nong Fu;
Jin-chun Wang;
Wei Wu;
Jing Wang;
Qiang Guo;
Jun-ming Liu
Show Abstract
Performance of IRFPA depends greatly on the amount and distribution of bad pixels. In this paper, general causes of bad
pixel in IRFPA are analyzed. Most bad pixels of IRFPA can be classified into four types for flip-chip bonding structure.
The amount of bad pixels in IRFPA often increases after long-term operation. This strongly affects application of IRFPA.
High temperature storage and temperature shock are effective ways to expose these potential bad pixels in advance. High
temperature storage and temperature shock are carried out on some IRFPA samples. Four kinds of variation for bad
pixels are investigated. They are variations of amount, characteristics, bad pixels on margin and bad pixels in different
IRFPA. Results show potential bad pixels damaged after these tests. New bad pixels are tested, analyzed and classified.
Each type of bad pixel is corresponding to defect of specified manufacture procedure. This indicates the potential
improving directions. Methods that could reduce bad pixels are briefly discussed. Results shown in this paper can help to
improve manufacture technology of IRFPA and then the performance of infrared imaging system.
The research of real-time image stabilization in the focal plane based on motion detection
Author(s):
Wei Zhou;
Chan Tan;
Lei Ding;
Haodong Pei
Show Abstract
An active focal plane motion compensation system is presented in this paper. In this system, a high
speed matrix CCD sensor is used for image motion detection. The matrix CCD sensor is a auxiliary sensor (about
256X256 pixel) which is installed side by side with the main image sensor of the camera. The main image sensor is
putted on a micro-displacement platform which is drived by tow piezoelectric actuators. So the main image sensor can
shift in tow directions. In order to realize real-time image motion estimation,the Gray Projection algorithm is used to
calculate image motion vector. To achieve the required accuracy, the operation of the piezoelectric actuator is controlled
in a closed loop system. The results of simulation experiments showed that the accuracy of the motion detection can
reach 0.5 ~1 pixel size, and the compensation can be controlled on the scale of sub pixel. theory analyzing demonstrate
that proposed method is reasonable and efficient. It will be helpful for space cameras to acquire high resolution images
on unstable space platforms .
Performance evaluation of imaging seeker tracking algorithm based on multi-features
Author(s):
Yujue Li;
Jinglong Yan
Show Abstract
The paper presents a new efficient method for performance evaluation of imaging seeker tracking algorithm. The method
utilizes multi features which associate with tracking point of each video frame, gets local score(LS) for every feature,
and achieves global score(GS) for given tracking algorithm according to the combined strategy. The method can be
divided into three steps. In a first step, it extracts evaluation feature from neighbor zone of each tracking point. The
feature may include tracking error, shape of target, area of target, tracking path, and so on. Then, as to each feature, a
local score can be got rely on the number of target which tracked successfully. It uses similarity measurement and
experiential threshold between neighbor zone of tracking point and target template to define tracking successful or not.
Of course, the number should be 0 or 1 for single target tracking. Finally, it assigns weight for each feature according to
the validity grade for the performance. The weights multiply by local scores and normalized between 0 and 1, this gets
global score of certain tracking algorithm. By compare the global score of each tracking algorithm as to certain type of
scene, it can evaluate the performance of tracking algorithm quantificational. The proposed method nearly covers all
tracking error factors which can be introduced into the process of target tracking, so the evaluation result has a higher
reliability. Experimental results, obtained with flying video of infrared imaging seeker, and also included several target
tracking algorithms, illustrate the performance of target tracking, demonstrate the effectiveness and robustness of the
proposed method.
X-ray diffraction analysis of high quality InAs/GaSb Type II superlattices grown by MBE
Author(s):
Yi Zhou;
Jianxin Chen;
Qingqing Xu;
Li He
Show Abstract
High resolution X-ray diffraction is used to study InAs/GaSb superlattices structural properties. The SL materials
were grown by molecular beam epitaxy on the GaSb substrates. We optimize the shutter sequences and soak time to
improve the SL interface and the material quality. The reciprocal space maps show that the materials are almost fully
stained. The angle distance between the zeroth order SL peak and the substrate in ω - 2θ spectrum is about 10 arcsec.
The full-width half-maximum (FWHM) of the zeroth order SL peak is 25 arcsec. Using a four layer model including two
InSb interfaces, we simulated the scanning curve and found there is different layer formed in InAs-on-GaSb and
GaSb-on-InAs interfaces. The arsenic pressure and the interface structure are optimized to get better material quality for
long wavelength SL samples. With optimized growth condition and suitable InSb-like interface structure, high quality SL
samples for both mid and long wavelength range are fabricated. The average roughness from AFM on a 2×2 um2 scan
area is less than 1.5 angstrom.
Response characteristic of InSb IRFPA under high reverse bias condition
Author(s):
Jun-ming Liu;
Qiang Guo;
Wei Wang;
Zhen-yu Peng
Show Abstract
Infrared Focal Plane Array (IRFPA) of InSb is designed to work under the condition of zero bias voltage or nearly to
zero bias voltage. InSb IRFPA can't work normally if PN junction is in the condition of high reverse bias voltage for
several minutes. In order to analyze the causation of the phenomena some experiments were designed to simulate the
condition of high reverse bias voltage. It is found that when the reverse bias voltage exceeds the limited value, the
responsibility of InSb detector becomes lower. The phenomena will not change unless the operating temperature is raised
to room temperature and kept for a long time. Response characteristic of InSb PN junction under high reverse bias
voltage is briefly described in this paper. The factors affecting response characteristic are discussed. The limited value of
the reverse voltage is given. The result is useful to design the driving circuit of InSb IPFPA. It also plays the guidance
part in application of InSb detector.
Application of multiple projector technologies for HWIL simulations
Author(s):
Hong Yu;
Jindong Fei;
Zhaowei Yang;
Huijie Du;
Yang Gao;
Yi Zhang
Show Abstract
IR projectors applied in HWIL simulations are responsible for generating a radiometric output which is similar to the
imager output for a real world targets and background in desired wavelength to the seeker under test. Projector
technologies meet more challenge as seekers performances improving. A variety of projectors has been constructed to
satisfy different use. This paper describes three projectors which include a dual-band IR extended source projector, a
MWIR Digital Micromirror Device(DMD) projector and a LWIR resistive array projector.
The evaluation of curved extended electrodes for off-area bonding of HgCdTe photoconductive detectors
Author(s):
Dahan Qian;
Jia Jia;
Yidan Tang;
Fuhao Liu;
Xueliang Ma;
Liyao Zhang;
Fei Liu;
Baisong Ye;
Hui Qiao;
Longyuan Zhu;
Xiangyang Li
Show Abstract
The formation process of devices' electrodes is one of the key techniques in the fabrication of HgCdTe infrared
photoconductive detectors. A new structure of extended electrode has been developed and improved for low temperature
stability. The parts of HgCdTe wafers exposed by photolithography are first dry etched until the sapphire substrate by
ion beam milling (IBM). Then the contact metal films are deposited on HgCdTe and sapphire respectively. The main
innovation of this paper is the optimization of the thickness of contact metal films. The traditional method of evaluation
the stability of electrodes is to measure the changes of resistance when the devices are taken from normal temperature
into low temperatures. Nevertheless, the changes of resistance are not sensitive to microdefects. So as to the effective
evaluation of the contact metal films, another means (SEM) is utilized to get details about the microstructure of the
contact metal films on the sidewall. In this paper, the topography of the improved sidewall contact metal was
investigated by SEM. The outcome shows that a continuous columnar structure is gained by that optimization. No voids
could be seen in the contact metals on the sidewall of etched HgCdTe, which reveals that the improved process is valid.
It also indicated that SEM is a reasonable and efficient means to evaluate the quality of deposited metal film on the
sidewall of a mesa structure in the fabrication of HgCdTe photoconductive detectors.
The study of a linear optimal location the typhoon center automatic from IR satellite cloud image
Author(s):
Yan Li;
Xi Chen;
Shu-ming Fei;
Ke-Feng Mao;
Kai Zhou
Show Abstract
The typhoon center location is important for forecast typhoon path and harmful weather. However, the appearance
of the typhoon from satellite cloud images was very complex and stochastic. Some location methods were short of
robustness and oneness. In order to locate the typhoon center automatically and accurately, we propose a linear optimal
location technique based on the feature of typhoon cloud circumgyrate the typhoon center. Grounded on the feature ,we
extracted the typhoon swirl feature using eigenvector which is denoted by the tangent of typhoon cloud image's gray
gradient. Then, we gain the solution of location optimal target equation using genetic algorithms, but this method has the
disadvantages of slow convergence and poor stability ,so an improved genetic algorithm is proposed in terms of creation
of the initial population and genetic operators. In the end, comparing general genetic algorithm with improved genetic
algorithm in convergence. We applied our approach to locate the center of some different typhoons occurred in 2008,
from the results of simulation experiments, we conclude that the method presented cloud identify the typhoon center
feature easily and locate the typhoon center accurately. Theory analysis and experiment shows the method is reasonable
and efficient.
A real-time gray projection algorithm for electronic image stabilization
Author(s):
Weiping Yang;
Zhilong Zhang;
Yan Zhang;
Xinping Lu;
Jicheng Li;
Zhiquang Shi
Show Abstract
Electronic digital image stabilization technique plays important roles in video surveillance or object acquisition.
Researchers have presented many useful algorithms, which can be classified to three kinds: gray based methods,
transformation based methods and feature based methods. When scenario is simple or flat, feature based methods
sometimes have imperfect results. Transformation based methods usually accompany large computation cost and high
computation complexity. Here we presented an algorithm based on gray projection which divided the whole image into
four sub-regions: the upper one, the bottom one, the left one and the right one. For making the translation estimation
easier, a central region is also chosen. Then the gray projections of the five sub-regions were counted. From the five pairs
of gray projections five group offsets including rotation and translation were obtained via cross correlation between
current frame and reference frame gray projections. Then according to the above offsets, the required parameters can be
estimated. The expected translation parameters(x axis offset and y axis offset) can be estimated via the offsets from the
central region image pair, the rotation angle can be calculated from the left four groups offsets. Finally, Kalman filter was
adopted to compute the compensation. Test results show that the algorithm has good estimation performance with less
than one pixel translation error and 10 percent rotation error. Based on this kind of gray projection algorithm, a real-time
electronic digital image stabilization system has been designed and implemented. System tests demonstrate the system
performance reaches the expected aim.
Design of a low noise and high accuracy readout integrated circuit for infrared detectors
Author(s):
Dong Yang;
Hang-yu Zhou;
Jian Wang
Show Abstract
In this paper, a low noise and high accuracy readout integrated circuit (ROIC) for Infrared
detectors is presented. The circuit is made up of capacitor trans-impedance amplifier (CTIA) and
correlation double sampling (CDS) circuit. First, the accuracy, and injection efficiency of the CTIA
structure which is used to convert the photo-current into voltage are fully discussed. The readout
accuracy of weak current signal can be obviously improved by the using of CTIA. Then, the CDS
structure with offset calibration technique is used to reduce the fixed pattern noise (FPN) of
CTIA. Thus, the signal to noise ratio (SNR) of the designed readout circuit is improved. By
utilizing the above two techniques, the influence of noise on this circuit was greatly reduced
and the precision of the ROIC was improved. Besides, the design of amplifier in CTIA is
discussed in more detail, which will bring about important effect on performance of the whole
circuit. Simulation results at Cadence Spectre demonstrated that the readout circuit had reached the
requirement of application. The final chip was fabricated with Chartered 0.35um standard
CMOS process. Testing results show that the linearity of CTIA is 99%, and that the readout
accuracy is 10-bit, while the detecting current varies from 10pA to 10nA. Furthermore, the
infrared image is shown in this paper, which means that the ROIC has a good performance at
the practical application.
The new approach for infrared target tracking based on the particle filter algorithm
Author(s):
Hang Sun;
Hong-xia Han
Show Abstract
Target tracking on the complex background in the infrared image sequence is hot
research field. It provides the important basis in some fields such as video monitoring, precision,
and video compression human-computer interaction. As a typical algorithms in the target tracking
framework based on filtering and data connection, the particle filter with non-parameter
estimation characteristic have ability to deal with nonlinear and non-Gaussian problems so it were
widely used. There are various forms of density in the particle filter algorithm to make it valid
when target occlusion occurred or recover tracking back from failure in track procedure, but in
order to capture the change of the state space, it need a certain amount of particles to ensure
samples is enough, and this number will increase in accompany with dimension and increase
exponentially, this led to the increased amount of calculation is presented. In this paper particle
filter algorithm and the Mean shift will be combined. Aiming at deficiencies of the classic mean
shift Tracking algorithm easily trapped into local minima and Unable to get global optimal under
the complex background. From these two perspectives that "adaptive multiple information fusion"
and "with particle filter framework combining", we expand the classic Mean Shift tracking
framework .Based on the previous perspective, we proposed an improved Mean Shift infrared
target tracking algorithm based on multiple information fusion. In the analysis of the infrared
characteristics of target basis, Algorithm firstly extracted target gray and edge character and
Proposed to guide the above two characteristics by the moving of the target information thus we
can get new sports guide grayscale characteristics and motion guide border feature. Then proposes
a new adaptive fusion mechanism, used these two new information adaptive to integrate into the
Mean Shift tracking framework. Finally we designed a kind of automatic target model updating strategy to further improve tracking performance. Experimental results show that this algorithm
can compensate shortcoming of the particle filter has too much computation, and can effectively
overcome the fault that mean shift is easy to fall into local extreme value instead of global
maximum value .Last because of the gray and fusion target motion information, this approach also
inhibit interference from the background, ultimately improve the stability and the real-time of the
target track.
Research on infrared dim-point target detection and tracking under sea-sky-line complex background
Author(s):
Yu-xing Dong;
Yan Li;
Hai-bo Zhang
Show Abstract
Target detection and tracking technology in infrared image is an important part of modern
military defense system. Infrared dim-point targets detection and recognition under complex
background is a difficulty and important strategic value and challenging research topic. The main
objects that carrier-borne infrared vigilance system detected are sea-skimming aircrafts and
missiles. Due to the characteristics of wide field of view of vigilance system, the target is usually
under the sea clutter. Detection and recognition of the target will be taken great difficulties .There
are some traditional point target detection algorithms, such as adaptive background prediction
detecting method. When background has dispersion-decreasing structure, the traditional target
detection algorithms would be more useful. But when the background has large gray gradient,
such as sea-sky-line, sea waves etc .The bigger false-alarm rate will be taken in these local area .It
could not obtain satisfactory results. Because dim-point target itself does not have obvious
geometry or texture feature ,in our opinion , from the perspective of mathematics, the detection of
dim-point targets in image is about singular function analysis .And from the perspective image
processing analysis , the judgment of isolated singularity in the image is key problem. The
foregoing points for dim-point targets detection, its essence is a separation of target and
background of different singularity characteristics .The image from infrared sensor usually
accompanied by different kinds of noise. These external noises could be caused by the
complicated background or from the sensor itself. The noise might affect target detection and
tracking. Therefore, the purpose of the image preprocessing is to reduce the effects from noise,
also to raise the SNR of image, and to increase the contrast of target and background. According
to the low sea-skimming infrared flying small target characteristics , the median filter is used to eliminate noise, improve signal-to-noise ratio, then the multi-point multi-storey vertical Sobel
algorithm will be used to detect the sea-sky-line ,so that we can segment sea and sky in the image.
Finally using centroid tracking method to capture and trace target. This method has been
successfully used to trace target under the sea-sky complex background.
Study of SF6 gas decomposition products based on spectroscopy technology
Author(s):
Ji-xing Cai;
Yan-xiang Na;
Wei-yuan Ni;
Guo-wei Li;
Ke-cheng Feng;
Gui-cai Song
Show Abstract
With the rapid development of power industry, the number of SF6 electrical equipment are increasing, it has gradually
replaced the traditional insulating oil material as insulation and arc media in the high-voltage electrical equipment. Pure
SF6 gas has excellent insulating properties and arc characteristics; however, under the effect of the strong arc, SF6 gas
will decompose and generate toxic substances, then corroding electrical equipment, thereby affecting the insulation and
arc ability of electrical equipment. If excessive levels of impurities in the gas that will seriously affect the mechanical
properties, breaking performance and electrical performance of electrical equipment, it will cause many serious
consequences, even threaten the safe operation of the grid.
This paper main analyzes the basic properties of SF6 gas and the basic situation of decomposition in the discharge
conditions, in order to simulate the actual high-voltage electrical equipment, designed and produced a simulation device
that can simulate the decomposition of SF6 gas under a high voltage discharge, and using fourier transform infrared
spectroscopy to analyze the sample that produced by the simulation device. The result show that the main discharge
decomposition product is SO2F2 (sulfuryl fluoride), the substance can react with water and generate corrosive H2SO4(sulfuric acid) and HF (hydrogen fluoride), also found that the increase in the number with the discharge, SO2F2concentration levels are on the rise. Therefore, the material can be used as one of the main characteristic gases to
determine the SF6 electrical equipment failure, and to monitor their concentration levels.
High quality mid-infrared InAs film grown on (100) GaSb substrate by LPE using a ternary melt
Author(s):
Changhong Sun;
Shuhong Hu;
Qiwei Wang;
Jie Wu;
Ning Dai
Show Abstract
InAs film has been successfully grown on (100) GaSb substrate using a ternary In-As-Sb melt by
liquid phase epitaxy (LPE). The high resolution X-ray diffraction (HRXRD) and Rocking curve
showed the film was single crystalline InAs with high quality. The Fourier transform infrared (FTIR)
transmission spectrum revealed that the cutoff wavelength was about 3.8 μm at room temperature. The
electron mobility at 300 K is higher than 2×10 4cm2/Vs. It indicates that the structure of InAs/GaSb
prepared by LPE has a potential for mid-infrared devices.
Research on an Al\SiNx bi-material thermal-mechanical uncooled infrared FPA pixel
Author(s):
Xia Zhang;
Da-cheng Zhang
Show Abstract
AlSiNx bi-material thermal strain structure is used in uncooled optic readout infrared focal plane array (UOR IR FPA)
pixel based on Micro-Electro-Mechanical Systems (MEMS) technology. In this paper, the problems that the AlSiNxstructure prevents FPA pixel scaling down and fill factor improving, and the Au reflection layer of the pixel leads to
larger readout light energy loss are analyzed. The feasibility of AlSiNx instead of AlSiNx in the UOR IR FPA
fabrication is researched in detail. The theoretical analyzing and simulation results demonstrate that, with optimized
thicknesses and their matching designing of SiNx and Al, the thermal-mechanical response of AlSiNx bi-material
structure is improved to 1.8 times and the intensity of optic readout signal is improved to about 2 times compared with
AuSiNAlSiNx one.
Based on momentum method BP neural network in the target recognition research and application
Author(s):
Xue-feng Zhang;
Yu-bin Gao
Show Abstract
Target recognition is measured by treating target existing knowledge to
judge, analyze, and thus the process of target identification. Using anti-vibration
lateral shearing interferometer to get the interference fringe for the spectrum
information of measurement target, and the system can get the target by spectrum
identification algorithm. By the condition that interferometer's length isn't changed,
the system was optimized by momentum BP Neural Network algorithm in the
separating mixed spectrum process, therefore it could improve the probability of
camouflage target recognition. The spectrum information was calculated by the
fringes, to getting the mixed spectrum data. The absorption spectrum was in the
hidden layer, and the system obtained every kinds of characteristic spectrum from
mixed spectrum by the momentum BP Neural Network. Experiments showed that it
collected mixed spectrum of background form different distances and different
surface, and made them to the initial spectrum information. The test target was a
board that it's surface was made to four kinds, and there was no paint (A), brushing
camouflage paint of military green (B), brushing camouflage paint of irregular shape
(C) and brushing camouflage paint of irregular box (D). The mixed spectrum was
obtained from the anti-vibration lateral shearing interferometer, while the recognition
probability for non-camouflage target were above 90.0% by the traditional algorithm
and the momentum BP neural network algorithm, but the recognition probability for
camouflage target was 85.6% by momentum BP neural network algorithm, better than
41.5% by the traditional algorithm, so it proved that the algorithm could improve the
recognition probability for camouflage target effectively.
Research on I-V temperature characteristic for InSb IRFPA
Author(s):
Qiang Guo;
Jun-ming Liu;
Wei Wang;
Jun-jie Si;
Jing Wang
Show Abstract
I-V temperature characteristic is very important to InSb IRFPA. In order to make further studies on I-V temperature
characteristic, some experiments were done. In the experiments, the operating temperature of the InSb array was
gradually raised from 77k. It is shown that reverse current doesn't simply increase with the increase of the operating
temperature. The reason can be attributed to the composing of reverse currents at different operating temperature. In this
paper, the I-V characteristic of InSb diode at different operating temperature is briefly described. The dominant
components of reverse current and its temperature characteristic are discussed. The change of detector impedance is
analyzed as operating temperature is changed. At the same time, the optimized operating temperature of InSb IRFPA is
presented. The limit of operating temperature at which InSb IRFPA can work normally is also given.
Effects of thermal annealing on HgCdTe/CdTe/Si(211) by MBE
Author(s):
Chuan Shen;
Renjie Gu
Show Abstract
In this paper, the effects of thermal annealing (TA) were studied by theoretical calculation and experiment. The
calculation was based on the Masafumi's model of dislocation movement, modified with thermal stress and
lattice-mismatch in the HgCdTe/CdTe/Si(211) heterostructure. As the calculation indicated, the temperature and holding
time of TA had great effect on the dislocation reduction, while less improvement with the epilayer thickness and growth
orientation. Upon the result of calculation, the TA and thermal cycle annealing (TCA) experiments were performed under
different conditions, which fit the calculation properly. The dislocation reduction of TA was investigated by double
crystal X-ray rocking curve (DCRC) and etch pit density (EPD) measurements. The EPD of 10μm SW~LW HgCdTe/Si
under optimized thermal process could be decreased half order of magnitude, with the lowest EPD at 2×106 cm-2, as well
as the full width at half maximum (FWHM) of the DCRC to 57.8 arcsec.
The sequence measurement system of the IR camera
Author(s):
Ai-hui Geng;
Hong-xia Han;
Hai-bo Zhang
Show Abstract
Currently, the IR cameras are broadly used in the optic-electronic tracking,
optic-electronic measuring, fire control and optic-electronic countermeasure field, but the output
sequence of the most presently applied IR cameras in the project is complex and the giving
sequence documents from the leave factory are not detailed. Aiming at the requirement that the
continuous image transmission and image procession system need the detailed sequence of the IR
cameras, the sequence measurement system of the IR camera is designed, and the detailed
sequence measurement way of the applied IR camera is carried out. The FPGA programming
combined with the SignalTap online observation way has been applied in the sequence
measurement system, and the precise sequence of the IR camera's output signal has been achieved,
the detailed document of the IR camera has been supplied to the continuous image transmission
system, image processing system and etc. The sequence measurement system of the IR camera
includes CameraLink input interface part, LVDS input interface part, FPGA part, CameraLink
output interface part and etc, thereinto the FPGA part is the key composed part in the sequence
measurement system. Both the video signal of the CmaeraLink style and the video signal of LVDS
style can be accepted by the sequence measurement system, and because the image processing
card and image memory card always use the CameraLink interface as its input interface style, the
output signal style of the sequence measurement system has been designed into CameraLink
interface. The sequence measurement system does the IR camera's sequence measurement work
and meanwhile does the interface transmission work to some cameras. Inside the FPGA of the
sequence measurement system, the sequence measurement program, the pixel clock modification,
the SignalTap file configuration and the SignalTap online observation has been integrated to
realize the precise measurement to the IR camera. Te sequence measurement program written by the verilog language combining the SignalTap tool on line observation can count the line numbers
in one frame, pixel numbers in one line and meanwhile account the line offset and row offset of
the image. Aiming at the complex sequence of the IR camera's output signal, the sequence
measurement system of the IR camera accurately measures the sequence of the project applied
camera, supplies the detailed sequence document to the continuous system such as image
processing system and image transmission system and gives out the concrete parameters of the
fval, lval, pixclk, line offset and row offset. The experiment shows that the sequence measurement
system of the IR camera can get the precise sequence measurement result and works stably, laying
foundation for the continuous system.
Improved sum-of-squared-differences tracking algorithm for thermal vision systems
Author(s):
Grzegorz Bieszczad;
Tomasz Sosnowski;
Henryk Madura
Show Abstract
A modification of Sum-of-Squared-Differences algorithm is proposed to improve tracking efficiency of small objects in
infra-red image sequences. The reason to use SSD algorithm is its better performance in tracking small objects, than in
model based tracking algorithms. However traditional Sum-of-Squared-Differences (SSD) algorithm is sensitive to
partial or full occlusions, background clutter and changes in object appearance. To increase immunity to this kind of
noises the modification in model update procedure was developed. The experimental results illustrate that the proposed
modification to SSD algorithm can improve overall algorithm performance in infrared operation. The paper describes the
Sum-of-Squared Differences algorithm and its principal features in tracking objects on thermal image sequences. Next
modification to SSD algorithm is described. Finally the experimental results are presented with comparison between
traditional and modified SSD algorithm.
Preparation and characteristics of PLZT (8/65/35) thin films by sol-gel method
Author(s):
Xiaotao Sun;
Weiguo Liu;
Shun Zhou;
Jianqiang Luo
Show Abstract
(Pb,La)(Zr,Ti)O3 is a ferroelectric material which has excellent pyroelectric, dielectric and ferroelectric properties,
and has a wide application prospect in the field of microelectronics and integrated circuit. A variety of techniques have
been used for the deposition of ferroelectric thin films, among the processes, the sol-gel method has its advantages. In
this study, the pyroelectric lead lanthanum zirconnate titanate (PLZT) (8/65/35) thin films were prepared on Pt
(111)/Ti/SiO2/Si (100) substrates using sol-gel method and their characteristics were analyzed. The orientation and
structural properties of the PLZT films were measured by X-ray diffractometer (XRD) and scanning electron microscope
(SEM), respectively. It was found that PbTiO3 (PT) can promote the crystallinity of PLZT thin films. According to the
results of the SEM, under the 700°C holding temperature, the lead content of PLZT films decreased with the increment
of holding time. The ferroelectric hystersis loop, pyroelectric coefficient and dielectric constant were also measured. The
electrical properties of the films were optimized by rapid thermal process (RTP) at 700°C. Ferroelectric hysteresis loop
of PLZT thin film with PT seed layer was tested at the triangular wave voltage of 50V. The results showed that the
remanent polarization (Pr) was 25.7 μC/cm2 and the coercive strength (Ec) was 68 kV/cm. At 1 kHz, dielectric constant
(εr) of 951 and dielectric loss (tanδ) of 0.048 were obtained, respectively. The pyroelectric coefficient was 1125μC/m2K.
The results demonstrated that PLZT thin films could be prepared by sol-gel method and had good ferroelectric, dielectric
and pyroelectric properties.
Compact middle infrared zoom lens design
Author(s):
Xuan-zhi Zhang;
Ming-yin Jiao;
Yadong Luan;
Wei-jun Chang;
Ting Sun
Show Abstract
A compact mid-wavelength infrared zoom camera with a zoom range of 15:1 and active athermalization has been
developed. The moving groups for a wide zoom range are only two lens groups and moving machanisms of zoom are
very simple, which allows easy access of opto-mechanical and electromechanical design. The final design adopts the
configuration of reflective mirror fold, comprising of two mirrors and eleven refractive lenses made of two infrared
materials such as germanium or silicon. The movement of the lens groups and the focal length of the system are smooth
and continuous. The zoom lens has the advantages of simple structure, high image quality, simple moving lens groups,
short zoom path and smooth zoom locus.
Accuracy assessment for infrared camera laboratory radiometric calibration
Author(s):
Xu-fen Xie;
Wei Zhang;
Hong-bin Nie;
Yi-ming Cao;
Qiang Wang;
Hong-yuan Wang
Show Abstract
An accuracy assessment method of infrared camera laboratory radiometric calibration was studied for the sake of
validation of space infrared camera measured data. Firstly, image process of infrared camera was analyzed and modeled
on laboratory radiometric calibration, a model of linear radiometric calibration coefficient synthesized impact chain was
built; secondly, based on the model, a model of uncertainty of linear radiometric calibration coefficient was built; finally,
An experiment verified the validity of the model. The results of experiment indicate that the difference between the
assessment value and maximum experiment value is 0.08% and the difference between the assessment value and average
of experiment values is 0.79% at gain uncertainty assessment, the difference between the assessment value and
maximum experiment value is 0.7%, the difference between the assessment value and average of experiment values is
0.18% at offset uncertainty assessment, the uncertainty of coefficients of radiometric calibration get from experiments is
basically consistent with the assessment. The method of accuracy assessment of radiometric calibration combined with
chain factors uncertainty can avoid omitting and repetition in uncertainty estimation; optimization of camera used for
quantification can be designed on the method.
A new FOD recognition algorithm based on multi-source information fusion and experiment analysis
Author(s):
Yu Li;
Gang Xiao
Show Abstract
Foreign Object Debris (FOD) is a kind of substance, debris or article alien to an aircraft or system, which
would potentially cause huge damage when it appears on the airport runway. Due to the airport's complex
circumstance, quick and precise detection of FOD target on the runway is one of the important protections for
airplane's safety. A multi-sensor system including millimeter-wave radar and Infrared image sensors is
introduced and a developed new FOD detection and recognition algorithm based on inherent feature of FOD
is proposed in this paper. Firstly, the FOD's location and coordinate can be accurately obtained by
millimeter-wave radar, and then according to the coordinate IR camera will take target images and
background images. Secondly, in IR image the runway's edges which are straight lines can be extracted by
using Hough transformation method. The potential target region, that is, runway region, can be segmented
from the whole image. Thirdly, background subtraction is utilized to localize the FOD target in runway region.
Finally, in the detailed small images of FOD target, a new characteristic is discussed and used in target
classification. The experiment results show that this algorithm can effectively reduce the computational
complexity, satisfy the real-time requirement and possess of high detection and recognition probability.
Ground experiment of infrared characteristics of space target
Author(s):
Weina Ke;
Guobiao Cai;
Dingqiang Zhu;
Wentao Shen;
Jiaqi Liu;
Weidong Wang;
Lei Yuan
Show Abstract
A experiment of infrared characteristics of space target have been carried out in situ using ground equipments to better
study the rule of the parameters related to the object characteristics. The experimental facility is realized in the
laboratory. This facility serves two purposes, one is to verify the feasibility of the ground test for infrared characteristics
of space target, and the other is to supply the required data for target characteristics simulations. The target characteristic
ground experimental system consists of a space environment simulator, a space target simulator and infrared signal
measuring apparatus. The space environment simulator afford an condition that the vacuum pressure is 10-4Pa, 80K ,
absorptivity about 0.9 radiation shield, and the radiation sources similar to the space environment. The different
experiments based on different flight parameters of the same target were carried out like system engineering. The
experiment results are consistent with the results of simulation and theory analyzing. The experiment is reasonable and
efficient, which contributes to the research on the characteristic of target, and parts of the experiment system give a new
method to the similar study.
Photoelectron characteristics of HgInTe detector
Author(s):
L. Zhang;
X. L. Zhang;
W. G. Sun;
Z. X. Lu
Show Abstract
We present the high performance of Hg3In2Te6 metal-semiconductor photodetectors using Indium tin oxide (ITO) as the
schottky electrodes by vacuum magnetron sputtering.There is a interfacial oxide layer formation by oxygen plasma
process between Indium tin oxide (ITO) and Hg3In2Te6 semiconductor compound to change schottky barrier. The effects
of oxygen plasma treatment on Hg3In2Te6 surface property were studied. Under optimized condition, the surface of
Hg3In2Te6 is oxidated resulting in decreasing reverse dark current and increasing breakdown voltage, while the barrier
height increases from 0.5 to 0.58eV. This method is simple to fabricate high performance HgInTe devices.
The underwater camera calibration based on virtual camera lens distortion
Author(s):
Dahui Qin;
Ting Mao;
Peng Cheng;
Zhiliang Zhang
Show Abstract
The machine view is becoming more and more popular in underwater. It is a challenge to calibrate the camera
underwater because of the complicated light ray path in underwater and air environment. In this paper we firstly
analyzed characteristic of the camera when light transported from air to water. Then we proposed a new method that
takes the high-level camera distortion model to compensate the deviation of the light refraction when light ray come
through the water and air media. In the end experience result shows the high-level distortion model can simulate the
effect made by the underwater light refraction which also makes effect on the camera's image in the process of the
camera underwater calibration.
Anomalous hall effect in arsenic-doped HgCdTe grown by Te-rich LPE
Author(s):
Guang-Yin Qiu;
Chuan-Jie Zhang;
Yan-Feng Wei;
Xiao-Jing Chen;
Qing-Qing Xu;
Jian-Rong Yang
Show Abstract
The Hall Effect and resistivity of arsenic-doped HgCdTe epilayers grown by Te-rich liquid phase epitaxy (Te-rich LPE)
have been measured in the temperature range between 20 and 300 K at a magnetic field of 2 kG. Some arsenic-doped
HgCdTe layers show anomalous n-type characteristic after activation annealing. A simplified two-layer model is applied
to describe the anomalous Hall Effect of the arsenic-doped HgCdTe layers. The results show that the anomalous
characteristic of the epilayers is due to the n-type layer in the surface, which may be caused by the surface oxidation.
Based on the model, a computer program is applied to fit the experimental curves of Hall parameters. The results show
that the Hall parameters primarily depend on the charge density of the n-type surface layer. The theoretical curves based
on the model are consistent well with the experimental data.
Distribution of thermal discharge from a power station based on HJ-1B and FY-3 thermal infrared data
Author(s):
Ying Zhou;
Cailan Gong;
Yong Hu;
Qiang Chen
Show Abstract
This article is based on the thermal infrared data obtained from Environmental mitigation B satellite (HJ-1B)
and Storm III satellite (FY-3), using generalized single-channel method, retrieved the surface temperature of
costal sea around the Tianwan Nuclear Power Plant in winter and summer to get the quantitative information about the diffusion and gradient of the thermal discharge from the nuclear power station. Then the retrieval
results were compared with the MODIS sea surface temperature (SST) products. It indicated that the thermal
infrared data from HJ-1B and FY-3 were able to research on the distribution of thermal discharge. Furthermore,
based on inversion of the SST distribution map, spatial and temporal distribution variations of thermal
discharge were analyzed simply. The distribution is significantly different among the different seasons. During the winter months, the thermal discharge extended to a sector area around the power station, while in summer
it limited to a rater longer and narrower area in one side of the bay. And the area where the SST has increased
more than 3 °C in winter was much larger than that in summer.
Research of spectral curvature correction method for hyperspectral images
Author(s):
Lin Li;
Yong Hu;
Yueming Wang
Show Abstract
The hyperspectral imager is able to acquire space and spectral information of ground object
simultaneously. When using a prism splitting mode, different wavelengths of light will disperse nonlinearly in
spectral dimension after going through the slit and the prism. Due to the longer slit and different angles of
incidence, when going through the slit and the prism, the same wavelength of light will curve in space
dimension. For SWIR bands, the maximum shift is more than 1.5 bandwidth. The shift cannot be ignored, for is
alters the pixel spectral and reduces match accuracies between space and spectral information. In this paper, a correction method of non-uniform spectral radiance in hyperspectral image is put forward. First, the
laboratory spectral calibration is performed to acquire center wavelength and full width half maximum (FWHM)
of each band as well as each pixel. Secondly, for each band, the mean of center wavelength which is
calculated according to the results of the spectral calibration is regarded as each pixel's adjusted center
wavelength. For each band and each pixel, calculate the ratio coefficient based on adjacent bands, then
establish a ratio coefficient form of full pixels. At last, correct the image by looking up the form. By using MNF
transformation, a corrected image can be well evaluated, a brightness gradient of the images has been
removed and the phenomenon of image spectral radiance mixing has been reduced greatly, especially at the
edge of the image.
The research of piezoelectric actuator for cryogenic scanning application
Author(s):
Xuan Zhang;
Gao-fei Zhao;
Ming Pan
Show Abstract
This paper discusses piezoelectric bimorph actuator has been developed for use at cryogenic temperature as low as 120K.
A novel piezoelectric actuator has been designed and fabricated based on piezoelectric bimorph. On this basis, an optical
scanner has been developed that can be use for cryogenic scanning and point positioning. Complete experimental
platform and high resolution measuring system have been set up and the piezoelectric scanner has been tested in dynamic
scanning and static point positioning modes at both room temperature and cryogenic temperatures. The characteristics of
the piezoelectric scanner at cryogenic temperatures have been analyzed, which verify the feasibility of the use of
piezoelectric actuator for cryogenic optics applications. By analyzing the hysteresis characteristics of piezoelectric
ceramics and the mechanical structure of the entire scanner, we have corrected the non-linearity of the scanning system
through compensating driving voltage, which achieves a high linearity and pointing accuracy. The research in this paper
provides a new idea for the design of image plane scanning system in space infrared cryogenic optics. The cryogenic
piezoelectric actuator features large stroke, high precision, high linearity, not any friction, and is free of magnetic field
interference, which is very promising for space infrared cryogenic optical application.
Measurement of defect depth by peak second derivative method in pulse thermography
Author(s):
Lichun Feng;
Ruigang He;
Yan Zhang
Show Abstract
In pulse thermography, pulsed flash energy is applied to the surface and the temperature of the surface
is recorded and analysed. Generally the the flash duration is short and the heating could be taken as
impulse function. After the surface is heated instantaneously, heat goes down by conduction. If an area
has defect below, the temprature of this area will be different from the temprature of defect free area.
Analytic solution indicates that the time at which the temperature descending curve of the area with
defect below separate from the curve of the defect free area is proportional to the square of the defect
depth. Thus, if the deviation time is determined, the defect depth could be calculated.
In real inspection, different from theoretical model, the temperature decay curve may be noisy and
sometimes fluctuating. And due to the effect of three-dimentional conduction and different boundary
conditions the temperature decay curve is different from the theoretical solution under ideal conditions.
All these affect the identification of the deviation time and then affect the accurary of the depth
measurement. Peak temperature contrast and peak slope of temperature contrast methods are popularly
used in depth measurement, but all these two methods require the prior determination of a reference
point that is known to be on sound material. Peak second derivative method in log scale is a reference
free method which can somehow decrease the influence of noisy data and three-dimentioanl conduction.
To reduce the noise induced by derivation, fitted data instead of raw data is offten used. However, the
global data fitting is not suitable in some situation. In this paper, peak second derivative method based
on patial data fitting is proposed and results are discussed. The results show that this method could
improve the accuracy of depth measurement for CFRP specimen.
Risk analysis on fabrication process of IRFPA
Author(s):
Hong-hai Wang;
Xian-sheng Qin
Show Abstract
Because of the complexity and long cycle time which the fabrication process of IRFPA chip is, it is impossible that
getting a best value through a lot of experiences and tests. Monte Carlo simulation provides a way to analyze and get the
probability distribution of the process goal based on limited experience data. So we can maximally avoid taking the
poorer parameter and effectively shorten the developing term for IRFPA chip. In this paper, a general fabrication process
of IRFPA chip is analyzed by Monte Carlo simulation. According to the function relations between the principal
technical indexes and the main parameters of the process, the mathematics model is established. Applying computer
software, the process model will be operated based on any random parameter sequence from a random data producer,
and then the risk analysis result for the fabrication process of IRFPA chip is obtained. The result not only describes the
process goal probability distribution but also provides the optional parameter sequence of given process goal. So that
engineer can balance the control points of fabrication process to take suitable technical decision.
Study of the characteristics of VLWIR HgCdTe photovoltaic detectors in variable-area diode test structures
Author(s):
Xiaohui Xie;
Hua Hua;
Guangyin Qiu;
Qingjun Liao;
Xiaoning Hu
Show Abstract
This paper aims to analysis the characteristics of VLWIR HgCdTe detectors with n-on-p implanted planar junction. We
use the variable area test structures, which are used as an important tool to access the quality of the material, process and
surface passivation in HgCdTe device technology. Through analyzing the relation between the inverse of the zero-bias
resistance-area product of a diode and its perimeter-to-area ratio, we can distinguish the contributions of bulk and surface
effects, and calculate the minority carrier diffusion length, which can reflect the conditions of the HgCdTe epitaxy.
According to the results, we find the VLWIR HgCdTe detectors have abnormal current-voltage phenomenon at a low
temperature, which may be the results of a parasite p-n junction. Besides, through data analysis and curves fitting, we
find the surface current of the VLWIR HgCdTe diodes at 80K is nearly comparable with the bulk current.
A detecting algorithm of infrared armor target under complex ground background based on morphological wavelet
Author(s):
Cong-Li Wang;
Zhi-Bin Chen;
Ming-Xi Xue;
Bao-Hua Liu
Show Abstract
Detecting of infrared armor target is the important technology in watching ground target and technological
reconnaissance field. In most cases, the target is supposed either darker or brighter than its immediate adjacent
background thus a possibility is provided to detect infrared target. How to enhance the character of target area becomes a
hot research area because of its complex ground background. This paper advances a novel target detection method based
on morphological wavelet decomposition through calculating a global threshold. Its main idea is explained as follow:
First we set a global threshold value according to analyzing the distribution character of the image's histogram;
second, we decompose the image using the two-dimensional morphological haar wavelet according to this value: when
the maximum value is greater than it we use the maximum value of four pixels, and else we use the minimum; third, we
carry out differential operation about the detailed image including the horizontal and vertical image and make them into
binary image by a threshold value; at last we decompose the binary images and use their low frequency part to find the
target area by calculate the bolck's weight.
Through all of the steps above, the fast detection on infrared armor target under complex ground background can be
realized successfully. The algorithm has the next advantages: strong ability of detecting objects, small operation quantity
and good real-time performance etc. So it can be used widely and effectively in actual work.
Pulsed thermography detection of water and hydraulic oil intrusion in the honeycomb sandwich structure composite
Author(s):
Shi-bin Zhao;
Cun-lin Zhang;
Nai-ming Wu
Show Abstract
Water and hydraulic oil intrusion inside honeycomb sandwich Structure Composite during service has been
linked to in-flight failure in some aircraft. There is an ongoing effort to develop nondestructive testing methods to detect
the presence of water and hydraulic oil within the sandwich panels. Pulsed thermography(PT) represents an attractive
approach in that it is sensitive to the change of thermal properties. Using a flash lamp PT, testing can be applied directly
to the surface of the panel. The viability of PT is demonstrated through laboratory imaging of both water and hydraulic
oil within sandwich panels. The detection of water and hydraulic oil intrusion using a one-sided flash lamp PT is
presented. It is shown that simple detection, as well as spatial localization of water and hydraulic oil within sandwich
panels, and assign the quantity of water and hydraulic oil is possible.
Fabrication of vanadium dioxide polycrystalline films with higher temperature coefficient of resistance
Author(s):
Jinhua Li;
Ningyi Yuan;
Meiping Jiang;
Li Kun
Show Abstract
Vanadium Dioxide Polycrystalline Films with High Temperature Coefficient of Resistance(TCR) were fabricated by
modified Ion Beam Enhanced Deposition(IBED) method. The TCR of the Un-doping VO2 was about -4%/K at room
temperature after appropriate thermal annealing. The XRD results clearly showed that IBED polycrystalline VO2 films
had a single [002] orientation of VO2(M). The TCR of 5at.%W and 7at.% Ta doped Vanadium Dioxide Polycrystalline
Films were high up to -18%/K and -12%/K at room temperature, respectively. Using 7at.% Ta and 2at.% Ti co-doping,
the TCR of the co-doped vanadium oxide film was -7%/K and without hysteresis during temperature increasing and
decresing from 0-80°C. It should indicate that the W-doped vanadium dioxide films colud be used for high sensing IR
detect and the Ta/Ti co-doped film without hysteresis is suitable for infrarid imaging application.
Research on readout circuit for PVDF pyroelectric infrared detector
Author(s):
Baisong Ye;
Yonggang Yuan;
Fei Liu;
Xiangyang Li;
Jinglan Sun;
Xiangjian Meng;
Nengbin Cai
Show Abstract
Two types of readout integrated circuit named SFD and CTIA are proposed to match the PVDF pyroelectric IR detector.
By employing macro model and analyzing the parameters of detector, the best matching conditions including the input
reference noise, input impedance, input capacitance, and working point are investigated in details. Based on the property
of the AC output for PVDF detector, we propose a novel readout method, with which the ratio of signal to noise can be
greatly improved. Furthermore, the linearity and sensitivity for both circuits are discussed by the means of Spectre tools.
Characterization of CdTe passivation layers grown by evaporation with thermal treatments
Author(s):
Jing-jie Xu;
Hai-bin Li;
Xing-guo Chen;
Yan-feng Wei;
Chun Lin;
Jian-rong Yang
Show Abstract
CdTe surface passivation layers were deposited by thermal evaporation or electron beam evaporation on (111) HgCdTe
epilayers. The processes of CdTe layer deposition were carried out at different temperatures from 100°C to 250°C.
Furthermore, prepared samples were annealed at a temperature range between 150°C and 300°C. Directly, scanning
electron microscope (SEM) was used to evaluate the CdTe passivation layers. The structures of CdTe layers and the
interface of CdTe/HgCdTe were studied by scanning the cross section of the samples. The results showed that the
thermal treatments could merge grain boundaries. Otherwise, the compositional properties of samples were surveyed by
secondary ion mass spectroscopy (SIMS). A compact CdTe structure near the HgCdTe surface caused by heating
deposition and compositional interdiffusion at CdTe/HgCdTe interface were observed. Moreover, the X-ray diffraction
(XRD) curves of the layers showed that the CdTe crystal quality was improved by thermal diffusion. The experimental
results showed that both heating during the deposition process and annealing after growth can effectively improve the
quality of CdTe passivation layers.
The effect of depth on the quantitative estimation of defect size using pulsed thermography
Author(s):
Tie Feng;
Cunlin Zhang;
Lichun Feng
Show Abstract
Although active thermography has traditionally been regarded as a qualitative NDT method, its potential for
quantitative measurement of thermophysical properties including wall thickness, defect size and depth, thermal
diffusivity has been the subject of numerous investigations. An investigation into the effect of depth on the quantitative
estimation of defect size in metalic specimen has been undertaken using pulsed thermography. A 3D model based on
finite element method was used to simulate the heat conduction in a flat metal plate containing articial defects. The plate
is made of steel with known thermal properties. The defects of different depth are flat bottom holes simulating areas
damaged by corrosion. The goal of the1 research was to find if there is a possibility to combine pulsed thermography and
numberical modeling to determine the effect of depth on the quantitative estimation of defect size. The temperature
distribution on the metal surface can provide proper threshold value to extract edge of defect in thermography. A series of
specimen with circular defect of varying diameter and depth were tested. To solve this problem, we analysis the FEM
simulation results, investigate the relationship between measured value and true value, and introduce a correction factor
related to depth. Using this correction factor, its measured value in the thermography is quite close to the design size of
defect in the specimen.
Stripe noise reduction in MODIS data: a variational approach
Author(s):
Ning Ma;
Ze-ming Zhou;
Li-min Luo;
Min Wang
Show Abstract
According to the characteristics of MODIS data stripe noises, we propose a novel variational method for stripe noise
reduction. First we find the detectors contaminated by stripe noises by separating MODIS data into several subimages
due to the numbers of scan detectors. Then for subimages with stripe noises, we build an energy minimization problem
by combining two energy terms to find the solution as the destriped result. The first energy term uses variational
histogram matching method to remove detector-to-detector stripes and mirror side stripes while the second energy term
uses non-linear anisotropic diffusion method to remove the random noise of noisy stripes. The gradient descent flow is
applied to minimize the total energy functional and the numerical scheme is presented. Experimental results show that
the method can reduce stripes noises effectively.
Analysis of pn-junction degeneration in heating process for extended wavelength InGaAs detectors
Author(s):
Yao-ming Zhu;
Hong-hai Deng;
Peng Wei;
Xue Li;
Hai-mei Gong
Show Abstract
To improve the operability and rate of final products significantly, a novel process was proposed. Detectors with
cutoff wavelength at 1.7 μm and 2.4 μm were fabricated in different processes, and the electricity characteristics and
spectral response were measured. The novel process was analyzed by comparing the characteristics of the detectors. The
dark current and responsibility of the detectors with cutoff wavelength at 1.7 μm fabricated in the new process were
improved. However, the new process has negative effect on the detectors with cutoff wavelength at 2.4 μm. The pnjunction
degenerated and the leakage current increased sharply. In order to find the reasons of degeneration, the methods
of Auger electron spectroscopy (AES) and scanning capacitance microscope (SCM) were used. The results indicate that
the metal elements do not penetrate into the pn junction causing the sharp increase of leakage current, while the interface
states due to lattice mismatch are thermally activated causing the degeneration of pn- junction.
Recognition of distorted target based on Mexican hat optimum trade-off maximum average correlation height algorithm
Author(s):
Ji-yang Shang;
Chi Chen;
Wen-sheng Wang
Show Abstract
In order to solve the problem of inaccurate recognition for distorted target (the targets rotated in plane or scale changed)
in cluttered background among the image pattern recognition, combined with the Mexican Hat mother wavelet and the
Optimum Trade-off Maximum Average Correlation Height (OT-MACH) algorithm, the Mexican Hat Optimum Trade-off
Maximum Average Correlation Height (Mexican Hat OT-MACH) matched filter is designed. The Mexican Hat OT-MACH filter is obtained to recognize distorted target in cluttered background. The wavelet functions have the
multi-scale characteristic and can analyze the specific frequency information. Moreover, the Optimum Trade-off Maximum Average Correlation Height algorithm (OT-MACH) has three characteristics, namely high distortion tolerance,
suppressing noise and sharpening the correlation peak. Therefore, the new designed matched filter contains all the characteristics of the wavelet function and OT-MACH algorithm. In order to balance all the performances of the new designed Mexican Hat OT-MACH matched filter, the performance control parameters and the scale coefficient of the
Mexican Hat OT-MACH matched filter need to be set. Thus, the new designed Mexican Hat OT-MACH matched filter has high versatility. It can respond higher correlation peaks and has higher distortion tolerance to recognize various types of distorted targets in cluttered background. In order to prove the feasibility of the Mexican Hat OT-MACE filter and determine its distortion tolerance, a lot of computer simulation experiments have be done with the filter. Good effect can be obtained.
In-field stray light due to surface scattering effects in infrared imaging systems
Author(s):
Ke Sun;
Hou-man Jiang;
Xiang-ai Cheng
Show Abstract
In-field stray light caused by surface scattering is a serious problem in many infrared
imaging systems. Light that scattered from lenses in infrared imaging system produces a halo of stray light within the field of view and often degrades the performance of an optical system
especially irradiated by intensive light such as laser. The experiments are performed by using
infrared thermal imaging system, irradiated by CW DF infrared laser. The relationship between the diameter of saturated area on the detector and the incident laser irradiance is obtained, which can be well explained by the point spread function (PSF) of the optics including both diffraction and
scattering components.
Bonding quality evaluation of wind turbine blades by pulsed thermography
Author(s):
Rui-gang He;
De-juan Kong;
Zhi Zeng;
Ning Tao;
Cun-lin Zhang;
Li-chun Feng
Show Abstract
The glue defects of the wind turbine blades which are composed of the glass fiber reinforced plastic (GFRP)
composite plates make its strength greatly reduced, so security issues could be caused. To improve the safety of wind
turbine blades, nondestructive testing technique using pulsed thermography is being investigated in this study. The
results of ultrasonic C scan test were compared with the results of thermography. The current results indicated that both
methods can successfully detect two gluing situations. However, the inspect specimens need to be putted in the water in
the detection process by ultrasonic C scan, and the detection time lasts much longer than pulsed thermography. And in
situ applications, the measured wind turbine blades are normally in the size of several tens meter, and also only one side
is available for the inspection especially at the tip of blades. Thus, ultrasonic C scan of current experimental setup is not
suitable for the applications in the field. Pulsed thermography is not necessary to contact with inspected specimens. The
infrared results by pulsed thermography indicate that the shape and size of deficiency glue defects in the specimens show
good agreement with the real situation, so it is more suitable for the inspection in the field. The preliminary results in this
study indicate that pulse thermography can be used to detect glue faults of GFRP which are not too thick.
Design of infrared telephoto lenses for joint transform correlator
Author(s):
Yu Zhang;
Ji-yang Shang;
Zheng Li;
Wen-sheng Wang
Show Abstract
Infrared optical system has been widely used in many fields, especially in target detection and recognition. While the
virtue of infrared optical system is that it can not only detect great distance but also detect the target in the poor
conditions such as turbid air or smoke, flog and snow. Hybrid optoelectronic joint transform correlator (HOJTC) is very
useful for target detection and recognition. Exploiting the Fourier transform property of a lens, it can implement target
detection in real time. Designing perfect optical system is one of key technology of target detection.
In this paper, the infrared detector which we adopted is infrared focal plane arrays with working waveband 3-5μm. Its
resolving power is 30 lp/mm. For the infrared optical system, the effective focal length, relative aperture and the field of
view should be large enough to ensure the long distance and large field of view target can be detected. In hybrid
optoelectronic joint transform correlator, the light weight and big aperture of infrared optical system is required. For this
purpose, an aspheric surface is introduced and the telephoto lens is composed of the three pieces of lenses. The MTF
curve of the telephoto lens is close to diffraction limit. The result shows that the aspheric surface can not only simplify
and reduce the structure and weight of the system respectively, but also can effectively improve the image quality of the
system. This telephoto lens can be used in HOJTC for infrared target detection.
A novel junction profile measurement in HgCdTe epilayer by laser beam induced current
Author(s):
Haibin Li;
Jingjie Xu;
Songmin Zhou;
Chun Lin;
Li He
Show Abstract
A novel, sample junction profile measurement in HgCdTe epilayer is investigated. This measurement is used a scanning
laser microscope to obtain the laser beam induced current (LBIC) signals of photosensitive pixel arrays on a long beveled
HgCdTe epilayer, and the junction profile is extracted from the LBIC data. In this work, junctions are fabricated by B+
implantation, and the beveled surface which is about 10mm long and several micrometers deep is formed by wet-etching
way. Because of different epilayer thicknesses on the HgCdTe beveled surface, some n regions of pixels are totally
removed at the deeper side, and the others have residual n regions at the shallower side. Therefore the very position where
the LBIC signal begins to vanish would point out the boundary between junction region and non-junction region, and
then the junction depth is extracted from the boundary data. The lateral sizes of junction at different depths are
determined by the peak-to-peak space in LBIC signals. The junction profile of both Hg vacancies doped and Arsenic
doped HgCdTe was measured in this work. The junction depth is about 1.29μm in Hg vacancy doped HgCdTe and a
significant lateral expansion was observed at low temperature. The junction depth is about 5.48μm in arsenic doped
HgCdTe. Moreover, the new technique is applicable to either HgCdTe or other materials.
A novel 512x8 ROIC with time-delayed-integration for MW infrared focal plane array
Author(s):
Jun-ling Zhang;
Qi Feng
Show Abstract
In this paper a novel 512×8 readout circuit (ROIC) with time delayed integration (TDI) for middle wave (MW) infrared
focal plane array (IRFPA) is present. As we known TDI is delicately devised and used in readout circuit to effectively
increase the integration time and reduce the photon noise. At the same time, the bucket-brigade device (BBD) structure is
commonly used in TDI implementation due to its simplicity and small size in integration. We adopt eight-stage BBD
structure to get higher Signal-to-Noise ratio (SNR) and achieve faster image scanning speed for linear IRFPA in the 3μm
-5μm spectral band. Because the center distance between each pixel is 28μm×56μm, an input stage based on direct
injection (DI) which has high injection ratio and small layout area is proved to be suitable in this design. The detector
consists of two segments in a staggered format that reads out synchronously. In order to achieve high flexibility,
integration time can be controlled and the defective pixels can be de-selection manually. Some other features such as
bidirectional operation, integration time, readout mode, an adaptive charge capacity control method and power
consumption are also discussed in this article. The novel 512×8 ROIC is fabricated with 0.6μm double poly double metal
CMOS technology and interconnected with MW IRFPA using indium bump. The experiments show that our method can
achieve good performance of integration of MW signal both at room temperature and at 77K low temperature. The
power consumption of the circuit is about 30mW at 5V supply and the readout clock frequency is up to 4MHz.
Identification of spilled oils by NIR spectroscopy technology based on KPCA and LSSVM
Author(s):
Ailing Tan;
Weihong Bi
Show Abstract
Oil spills on the sea surface are seen relatively often with the development of the petroleum exploitation and
transportation of the sea. Oil spills are great threat to the marine environment and the ecosystem, thus the oil pollution in
the ocean becomes an urgent topic in the environmental protection. To develop the oil spill accident treatment program
and track the source of the spilled oils, a novel qualitative identification method combined Kernel Principal Component
Analysis (KPCA) and Least Square Support Vector Machine (LSSVM) was proposed. The proposed method adapt
Fourier transform NIR spectrophotometer to collect the NIR spectral data of simulated gasoline, diesel fuel and kerosene
oil spills samples and do some pretreatments to the original spectrum. We use the KPCA algorithm which is an extension
of Principal Component Analysis (PCA) using techniques of kernel methods to extract nonlinear features of the
preprocessed spectrum. Support Vector Machines (SVM) is a powerful methodology for solving spectral classification
tasks in chemometrics. LSSVM are reformulations to the standard SVMs which lead to solving a system of linear
equations. So a LSSVM multiclass classification model was designed which using Error Correcting Output Code
(ECOC) method borrowing the idea of error correcting codes used for correcting bit errors in transmission channels. The
most common and reliable approach to parameter selection is to decide on parameter ranges, and to then do a grid search
over the parameter space to find the optimal model parameters. To test the proposed method, 375 spilled oil samples of
unknown type were selected to study. The optimal model has the best identification capabilities with the accuracy of
97.8%. Experimental results show that the proposed KPCA plus LSSVM qualitative analysis method of near infrared
spectroscopy has good recognition result, which could work as a new method for rapid identification of spilled oils.
The design and simulation of single detector MIR spectrometer based on MEMS scanning mirror
Author(s):
Zhong-wei Zhang;
Zhi-yu Wen;
Tian-ling Zeng;
Kang-lin Wei
Show Abstract
Infrared (IR) spectrometers are very important optical equipments that can be used in industry, science, medicine,
agriculture, biology and food safety etc., and the market is growing. However, most traditional IR spectrometers, such as
Fourier transform spectrometer (FTS) that based on Michelson interferometer principle and scanning monochromator
that based on grating scanning, are expensive, relative large volume, and stationary, which can't meet the requirements of
specific application such as rapidity, special environment and some special samples. To overcome these drawbacks,
innovatory technology-micro electro mechanical systems (MEMS) technology was used in micro IR spectrometers in the
past few years. And several prototypes and products that based on several operational principles have been emerged. In
this paper, a novel IR micro spectrometer which based on MEMS technology and used single element detector was
presented over a wide spectral range (from 2500nm to 5000nm) in the mid infrared (MIR) wavelength regime, and the
optical system of it was designed on the basis of traditional scanning monochromator principle. In the optical system,
there is a highlighted characteristic that dual spherical focus mirror was used to focus the diffraction light of the
diffraction grating, which improved the spectral resolution of the optical system. Finally, using Zemax optical software,
three torsion angle locations were selected to simulate the optical system of the spectrometer with the slit's size
0.1mm×1mm. The simulation result indicated that in the whole wavelength range the spectral resolution of the optical
system was less than 30nm, and a high accuracy MIR spectrometer with compact volume will be realized in future
hopefully.
The research of infrared image segmentation based on mathematical morphology
Author(s):
Yicheng Wang;
Songfeng Yin;
Xiaodi Wu
Show Abstract
This paper describes a new method for infrared image segmentation based on mathematical morphology. The proposed
algorithm relies on four steps: First, to reduce the influence of asymmetrical background, top-hat transform was used,
and gradient image was obtained by morphological gradient transform. Second, gradient image was reconstructed by
reconstruction operator, which was constituted by doing opening by reconstruction operation and closing by
reconstruction operation successively. Through gradient image reconstruction, important region contours are preserved
while most tiny regular details and noises are removed. Finally, auto threshold technique was used to extract the region
edges form reconstructed gradient image. Experimental results show that the approach performs well in target
segmentation in infrared images with complicated background.
Research on IRST operating range model for point target based on natural sky background
Author(s):
Jihui Wang;
Weiqi Jin;
Zhiyun Gao;
Xiaowei Wang
Show Abstract
Background has a very important influence on point target operating range of infrared search and track system(IRST).
Based on the noise equation temperature difference(NETD) operating range model , a general noise parameter δ′ which
describes the influence of background and system noise on the operating range is presented, and a new operating range
model is founded including δ′. δ′ has clear meaning and gives explicit explanation for conventional detector-limited and
background-limited operating range model. The algorithm of δ′ based on the ratio of background region to target area is
proposed under natural sky background. The simulation shows that δ′ is valid for predicting point target operating range
of IRST.
Research on the sampling performance of the focal plane array thermal imaging systems
Author(s):
Jian-ping Cui;
Ji-hui Wang;
Wei-qi Jin;
Zhi-yun Gao;
Ting-zhu Bai
Show Abstract
Discrete sampling is one of the important characteristics of thermal imaging systems and has an important effect on the
target acquisition performance. Based on the study of discrete sampling theory, several discrete sampling evaluation
methods are analyzed, and the aliasing caused by under-sampling is considered as a noise of thermal imaging systems.
The aliasing noise is introduced into MRTD model with system noise. MRTD model with aliasing noise is deduced, and
its validity is verified by simulation experiments. MRTD model with aliasing noise is introduced into MRTD channel
width model. It is future work that the impact of discrete sampling on the general performance of thermal imaging
systems will be researched by MRTD channel width model.
The effect of infrared and visible image fusion on object tracking using correlation matching
Author(s):
Songfeng Yin;
Liangcai Cao;
Guofan Jin
Show Abstract
This paper studies on how the performance of object tracking using correlation matching can be affected by the
pixel-level infrared and visible image fusion approaches, as compared to tracking using single modality source images.
Several classic grayscale and color image fusion approaches have been investigated, with the former including traditional
DWT method and our proposed adaptive weighted average method based on fuzzy logic and the latter including both
linear and nonlinear color transfer methods. Object tracking in various conditions has been tested on a representative set
of both simulated and real captured image sequences. Experimental results suggest that the location precision and
robustness of object tracking can be improved effectively using fused images. Among the various tested fusion
approaches, the techniques of fuzzy logic based grayscale image fusion and nonlinear color transfer consistently offer the
best tracking performance.
Analysis and design of a low-noise ROIC for hybrid InGaAs infrared FPA
Author(s):
Wei Zhang;
SongLei Huang;
ZhangCheng Huang;
Jiaxiong Fang
Show Abstract
The noises of CMOS readout integrated circuit (ROIC) for hybrid focal plane array (FPA) may occupy a great part of
total noise in conditions that a low resistance or large capacitor detector interfacing with CTIA input stage. A novel low
noise low power preamplifier with shared current-mirrors bias is designed. It has a gain of more than 90dB, which makes
enough inject efficiency and low detector bias offset. Besides, it has strong detector bias control, because the shared
current-mirror copies the DC current of the amplifier and generates the bias control voltage. A pixel level Correlated
Double Sample circuits is designed in order to suppress the reset KTC noise and 1/f noise from preamplifier. An
experimental chip of 30μm pitch 32×32 array was fabricated in standard 0.5μm CMOS mixed signal process. A few
experimental structures are designed to study the allocating of layout area for low noise designing. The ROIC is bonded
to an existing back-illuminated 30μm pitch InGaAs photodiode array with indium bump fabrication. The test of both the
ROIC chips and InGaAs focal plane array is shown in this paper, and the contrast of different structure is shown and
analyzed.
Infrared imaging based on quantum dot optical phase modulation
Author(s):
Gang Chen;
Tao Yang;
Chen Peng;
Rainer Martini
Show Abstract
In the past two decades, there is an increasing interest in developing new infrared photodetectors based on novel
nanostructures, such as quantum well infrared photodetector (QWIP) and quantum dot infrared photodetector (QDIP).
However, the commonly used electrical read-out approach limits the resolution of QWIP/QDIP infrared imaging to
around 1 mega pixel. In this paper, we reported our theoretical study on an all-optical readout based on quantum dot
phase modulation, which provides a new way for the intersubband infrared detection by measuring the phase change in
the transmitted interband near infrared (NIR) and allows a high-resolution middle infrared (MIR) or far infrared (FIR)
imaging. Utilizing the long life time in the quantum dots, the intersubband infrared resonant light is used to control the
interband NIR resonant light phase. An infrared image can be converted into a visible or near infrared image, which can
be easily captured with a high resolution CCD camera. It provides a new way to obtain a high resolution infrared image.
Construction, parameters, and research results of thermal weapon sight
Author(s):
Tomasz Sosnowski;
Henryk Madura;
Grzegorz Bieszczad;
Mariusz Kastek;
Krzysztof Chmielewski
Show Abstract
The paper presents the thermal sight for small arms weapons, which can be classified as 3rd gen thermal camera. The
sight operates in LWIR (long wave infrared) spectra band and utilizes uncooled microbolometer focal plane array (FPA)
with stabilized temperature (by means of Peltier module). The assumed technical and tactical characteristics of the
presented sight were confirmed during laboratory test (including climate and vibration tests). The sight was also tested
during field trials conducted at Military Institute of Armament Technology, where it was mounted on seven different
weapon types with calibers from 5.56 to 12.7 mm.
Study of polishing of HgCdTe wafers
Author(s):
Li-yao Zhang;
Hui Qiao;
Jin-tong Xu;
Xiang-yang Li
Show Abstract
Wafer thinning is a key process in the fabrication of bulk HgCdTe photoconductive detectors. The currently
used method in SITP is chemo-mechanical polishing combined with a following bromine-ethanol etching, which leaves
a rough and non-stoichiometric composition surface. The thickness of damaged layer caused by chemo-mechanical
polishing might be several hundred angstroms, so the process of bromine-ethanol etching after the chemo-mechanical
polishing which could be used to remove the damages must last sufficient time, which would produce a Te-rich surface
because of different bond energy between Te-Cd and Te-Hg. In this paper, bromine-methanol polishing method was
used to reduce the surface damage of the HgCdTe wafer instead of bromine-ethanol etching, and it turned out that
bromine-methanol polishing could obviously reduce the damage depth and effectively produce a stoichiometric HgCdTe
surface comparing with bromine etching treatment. The related physical and chemical mechanism of
bromine-methanol polishing are analyzed and experiment results are presented in the paper. The AFM test showed that
the HgCdTe surface treated with bromine-methanol polishing had a roughness of about only 10nm, while the roughness
for bromine etching was about 30nm . In this work, the surface removing rate of bromine-methanol polishing and
minority carrier lifetime of HgCdTe wafer treated with bromine etching and bromine-methanol polishing were also
studied. The result shows that bromine-methanol polishing can improve the minority carrier lifetime significantly.
Through a series of experiments we come to a conclusion that the optimized bromine concentration was 1:260 and the
polishing time was one minute.
A new small and dim targets detection and recognition algorithm based on infrared dual bands imaging system
Author(s):
Bingjian Wang;
Gang Lu;
Liping Bai;
Qing Li;
Shangqian Liu
Show Abstract
In this paper, infrared radiation characteristics in different bands of flight targets, background
and decoys are analyzed. According to the analytical results, a new small and dim targets detection and
recognition algorithm based on infrared dual bands is present. Infrared dual bands imaging system includes
infrared mid-wavelength imaging system and infrared long-wavelength imaging system. Images from
these two imaging system are registered in time and space firstly. After background suppression, then the
small and dim targets are detected from MW infrared images and LW infrared images respectively. At last,
by using spatial correlation and spectral correlation of targets, interferes and decoys are eliminated from
target candidates. The genuine targets are separated and recognized. The algorithm is applied to simulation
dual bands images and real infrared dual band images. The experimental results show that the algorithm
present in this paper is effective.
Design of readout integrated circuit structure for single and dual band infrared detector with variable integration time
Author(s):
Tai-Ping Sun;
Yi-Chuan Lu;
Hsiu-Li Shieh;
Shiuan-Shuo Shiu;
Yi-Ting Liu;
Shiang-Feng Tang;
Wen-Jen Lin
Show Abstract
This paper proposes two kinds of readout integrated circuits for column and row interlaced dual-band infrared
detectors. The experiments were simulated using TSMC 0.35μm Mixed Signal 2P4M CMOS process and operated at
3MHz clock rate. The pixel dimensions for two kinds of readout integrated circuits were also 30×30μm. The mid-wave
and long-wave sense current was set from 1nA to 2nA and 6nA to 8nA, respectively. We designed a 40x16 array for the
columns interlace readout circuit. The output voltage swing was 2.8V. The frame rate was 4.68kFPS. The total power
consumption was less than 17.6mW. We also designed a 20x32 array for the row interlace readout circuit. The output
voltage swing was 2.8V. The frame rate was 2.67kFPS. The total power consumption was less than 11.4mW. The power
consumption increased when the column interlace frame rate reached the row interlace frame rate. The row interlace can
decrease the layout area by sharing the column stage circuit, but the frame rate will drop to half of the single band frame
rate.
Electro-optical system for gunshot detection: analysis, concept, and performance
Author(s):
M. Kastek;
R. Dulski;
H. Madura;
P. Trzaskawka;
G. Bieszczad;
T. Sosnowski
Show Abstract
The paper discusses technical possibilities to build an effective electro-optical sensor unit for sniper detection using
infrared cameras. This unit, comprising of thermal and daylight cameras, can operate as a standalone device but its
primary application is a multi-sensor sniper and shot detection system. At first, the analysis was presented of three
distinguished phases of sniper activity: before, during and after the shot. On the basis of experimental data the
parameters defining the relevant sniper signatures were determined which are essential in assessing the capability of
infrared camera to detect sniper activity. A sniper body and muzzle flash were analyzed as targets and the descriptions of
phenomena which make it possible to detect sniper activities in infrared spectra as well as analysis of physical limitations
were performed. The analyzed infrared systems were simulated using NVTherm software. The calculations for several
cameras, equipped with different lenses and detector types were performed. The simulation of detection ranges was
performed for the selected scenarios of sniper detection tasks. After the analysis of simulation results, the technical
specifications of infrared sniper detection system were discussed, required to provide assumed detection range. Finally
the infrared camera setup was proposed which can detected sniper from 1000 meters range.
Multisensor systems for security of critical infrastructures: concept, data fusion, and experimental results
Author(s):
M. Kastek;
R. Dulski;
M. Życzkowski;
M. Szustakowski;
W. Ciurapiński;
K. Firmanty;
N. Pałka;
G. Bieszczad
Show Abstract
The paper presents the concept of a multisensor system for perimeter protection, suitable for stationary and moving
objects. The system consists of an active ground radar and thermal and visible cameras. The radar allows the system to
locate potential intruders and controls an observation area for system cameras. The multi-sensor system concept ensures
significant improvement of the probability of intruder detection and reduction of false alarms, thus increasing the
functionality and performance of the whole system. Effective ranges of detection depend on the quality of the applied
sensors and the observed scene itself. One of the most important devices used in such systems are IR cameras. The paper
discusses the technical possibilities and limitations to use uncooled IR cameras in such a multi-sensor system for
perimeter protection. The role of IR cameras in the system was discussed as well as a technical possibilities to detect a
human being. The operational distances for perimeter protection are rather high, considering the performance of
commercially available thermal cameras. The required spatial resolutions for detection, recognition and identification
were calculated and then the detection ranges were estimated using NVTherm software. The results of analysis were
finally presented and the comparison of exemplary IR cameras.
Spectral measurements of muzzle flash with multispectral and hyperspectral sensor
Author(s):
M. Kastek;
R. Dulski;
P. Trzaskawka;
T. Piątkowski;
H. Polakowski
Show Abstract
The paper presents some practical aspects of the measurements of muzzle flash signatures. Selected signatures of
sniper shot in typical scenarios has been presented. Signatures registered during all phases of muzzle flash were
analyzed. High precision laboratory measurements were made in a special ballistic laboratory and as a result several
flash patterns were registered. The field measurements of a muzzle flash were also performed. During the tests
several infrared cameras were used, including the measurement class devices with high accuracy and frame rates.
The registrations were made in NWIR, SWIR and LWIR spectral bands simultaneously. An ultra fast visual camera
was also used for visible spectra registration. Some typical infrared shot signatures were presented. Beside the
cameras, the LWIR imaging spectroradiometer HyperCam was also used during the laboratory experiments and the
field tests. The signatures collected by the HyperCam device were useful for the determination of spectral
characteristics of the muzzle flash, whereas the analysis of thermal images registered during the tests provided the
data on temperature distribution in the flash area. As a result of the measurement session the signatures of several
types handguns, machine guns and sniper rifles were obtained which will be used in the development of passive
infrared systems for sniper detection.
Nonuniformity correction algorithm based on Gaussian mixture model
Author(s):
Xin-gang Mou;
Gui-lin Zhang;
Ruo-lan Hu;
Xiao Zhou
Show Abstract
As an important tool to acquire information of target scene, infrared detector is widely used in imaging guidance field.
Because of the limit of material and technique, the performance of infrared imaging system is known to be strongly
affected by the spatial nonuniformity in the photoresponse of the detectors in the array. Temporal highpass filter(THPF)
is a popular adaptive NUC algorithm because of its simpleness and effectiveness. However, there still exists the problem
of ghosting artifact in the algorithms caused by blind update of parameters, and the performance is noticeably degraded
when the methods are applied over scenes with lack of motion. In order to tackle with this problem, a novel adaptive
NUC algorithm based on Gaussian mixed model (GMM) is put forward according to traditional THPF. The drift of the
detectors is assumed to obey a single Gaussian distribution, and the update of the parameters is selectively performed
based on the scene. GMM is applied in the new algorithm for background modeling, in which the background is updated
selectively so as to avoid the influence of the foreground target on the update of the background, thus eliminating the
ghosting artifact. The performance of the proposed algorithm is evaluated with infrared image sequences with simulated
and real fixed-pattern noise. The results show a more reliable fixed-pattern noise reduction, tracking the parameter drift,
and presenting a good adaptability to scene changes.
Adaptive infrared image enhancement algorithm based on improved UM technique
Author(s):
Xin-sai Wang;
Qiang Wu;
Wei-ping Wang;
Ming He;
Yu Liu
Show Abstract
Infrared image enhancement is an important problem of infrared image processing. It gives rise to noise
amplification in smooth areas and excessive overshoot in detail areas in the process of classical UM(unsharp masking)
algorithm for infrared image enhancement. Aiming at above drawbacks, an adaptive method based on improved UM
algorithm for infrared image enhancement is proposed in the paper. Our approach employs an adaptive Gauss-Newton
filter to adjust the contrast enhancement parameters in different local areas, making sure that medium-contrast details are
enhanced as well as large-contrast details in the process of contrast enhancement, and avoiding noise amplification,
detail sharpening distortion and margin overshoot. Experiments show that the algorithm proposed in the paper is
effective to improve the SNR and enhance the details of infrared image.
The modulated photocurrent of amorphous HgCdTe thin films
Author(s):
Lianjie Yu;
Yanli Shi;
Jisheng Zhuang;
Xiongjun Li;
Gongrong Deng;
Lili Yang;
Wenjin He
Show Abstract
Amorphous HgCdTe thin films were deposited on quartz substrate by RF magnetron sputtering technique. The
modulated photocurrent(MPC) of amorphous HgCdTe thin films has been investigated as a function of temperature T,
the excitation light intensity F, and applied electric fields EB. The results indicated that the modulated photocurrent show
an activated behavior in the range of 80K-300K. The activated energy ΔEap of the modulated photocurrent was found to
strongly depend on temperature, whereas it is nearly independent of the applied electric field. The exponent γ in the
power law relationship (Ip∝Fγ) between excitation light intensity F and modulated photocurrent of amorphous HgCdTe
thin films was obtained at different temperature. The γ depends strongly on the temperature T, but it is independence of
applied electric fields EB. The values of exponent γ of amorphous HgCdTe thin films lie between 0.5 and 1.0. The results
indicated a continuous distribution of localized states exists in amorphous HgCdTe thin films.
Infrared image enhancement algorithm based on multiscale retinex with adaptive surround space constant
Author(s):
Yu Liu;
Xin-sai Wang;
Jing He;
Ming He;
Yong Zhang
Show Abstract
Retinex is an image enhancement algorithm based on color consistency theory which is originally used for color image
enhancement with a trade-off between dynamic range compression and tonal rendition, and these two effects are
combined with a weighted sum of several Single Scale Retinex (SSR) outputs, namely Multi Scale Retinex (MSR)
algorithm. For infrared image, it is known that the resulting effects of dynamic range compression and detail
enhancement are governed by the Gaussian surround space constant. Traditional MSR algorithm using fixed surround
space constants and can not automatically adjust each surround space constant for different images. This means, MSR
algorithm can not improve the image details and overall visual effects at the same time using local information of
infrared images. To overcome this problem, an MSR based image enhancement algorithm with adaptive surround space
constant is proposed. Firstly the image standard deviation is calculated to scale overall dynamic range, then the image is
divided into several sub-images, standard deviation and mean value of gradient for each sub-image are calculated to
measure the local complexity. The surround space constant in MSR algorithm is determined by both overall dynamic
range and local complexity that is acquired above to achieve an optimal enhancement output. Then intensity stretching is
used to produce a graceful visual effect. Experiment proved that the algorithm proposed in this paper improves the
quality of infrared images effectively, and has better adaptability than traditional MSR algorithm.
Analysis and simulation of the infrared characteristics of the aerial target
Author(s):
Sen Ma;
Xiao-xia Li;
Nan Zhao
Show Abstract
This paper consults and improves the on hand computational methods and circuits, which comprehensively utilizes the
knowledge of the Aerodynamics, the heat transfer theory, the radio optics, ANSYS and so on. In the analysis of the IR
characteristics of aerial targets, taking it into account that most of the computing methods on hand are empirical or
semi-empirical, which are more simple, but more limited, less sufficient and scientific and have more human factors, so
we begin with the determination of the thermal field, adopt the numerical method to realize the calculation and modeling
of the IR radiation with ANSYS, analysis how the spectral coverage and the observed bearing affect the IR radiation, and
then get the credible and all-side numerical calculation results.
Then, this paper introduces a method utilizing 3DS MAX and OpenGL to generate the IR picture of the target,
which divides the grey level of the IR radiation reasonably according to the final numeric calculating results and
the principle of the grey level division, and then we generate the IR pictures of the aerial targets.
The characteristic analysis and optimization design for HgCdTe TDI infrared detector array
Author(s):
Mei-feng Dong;
Xing Chen;
Guang-yin Qiu;
Xiao-hui Xie
Show Abstract
Time Delay Integration (TDI) is an effective approach for high sensitive infrared detectors. According to the principle of
the TDI, the central distance of pixel along the time delay integral direction is closely linked with the specific application
requirements. So the optimization design, such as the area of pixels and their distance, plays an important role to improve
the performance of TDI detectors. The crosstalk between pixels is a crucial factor that results in the decline of detector
Modulation Transfer Function (MTF), and then affects the imaging quality. In this paper the optimization design rule for
the arrangement of pixel has been investigated. The results show that the main method to appreciate it is reducing the
crosstalk between pixels and enhancing detectivity. Chips of which pixel areas and edge intervals are different but with
same distance were designed for the experiments. The optical and electrical measurements were carried out for these
chips and the optimized structure was obtained. In addition, relationships between the crosstalk and parameters of
material, pixel structure were analyzed based on the experiment data. According to the comprehensive analysis of the
measurement data, we obtained the optimum design for specific HgCdTe TDI infrared detector. Meanwhile it is also a
well reference for other HgCdTe TDI detector structure design.
Algebraic nonuniformity correction algorithm based on multiscale optical flow
Author(s):
Ming He;
Xin-sai Wang;
Qiang Wu;
Yu Liu;
Hua-liang Xu;
Dong Guo
Show Abstract
A multi-scale optical flow motion estimation based algorithm is developed for algebraic nonuniformity correction. First,
the algorithm use time domain low pass filter filtering the random image frames noise. Then, use multi-scale optical flow
estimation of the next frame. With these scene estimates and record frame, we can carry out nonuniformity correction.
The strength of the algorithm lies in its good noise immunity, simple calculation and ability of real time processing. The
fundamental and the flow of the proposed technique are described and the performance is demonstrated with infrared
camera developed.
Modify model for infrared dim target detection
Author(s):
Ruo-lan Hu;
Xiao Zhou;
Guo-hua Zhang;
Gui-lin Zhang
Show Abstract
More and more infrared imaging systems were applied in military and civil fields due to the ability of detecting in
night. Performance of detecting dim target is one important index for infrared imaging system. But it is difficult to detect
dim target from infrared image due to weak in luminous and small in sizes. An important approach based on background
suppression was used in many applications for it was effective in most applications and computed easily and quickly. But
the performance of target detection were descended with many numbers of false alarms when there exists noise pixels in
infrared image. In order to resolve the problem induced by noise pixels, in this paper a modify detection model was
proposed. Modify detection model use two step filter processes to suppress noise and estimate background image. After
selecting the first filter operator, a detection system base on modify detection model was realized. Experiment results
show that modify detection model improve target detection ratio and reduce the numbers of false alarm on noisy infrared
images.
Spray coater technology in HgCdTe third-generation infrared focal plane arrays
Author(s):
Wen-ting Yin;
Zhen-hua Ye;
Weiping Ma;
Yu Chen;
Xiao-ning Hu
Show Abstract
HgCdTe third-generation infrared focal plane arrays such as avalanche photodiodes, two-color detectors and multi-color
detectors usually have mesa microstructures, which bring on huge challenge in device technology, especially coating
resist process and exposing process. Using conventional spinning coater technology, the thickness of different position in
the structure usually is incoordinate, the resist in the bottom of trench is often very thick, but the resist on the top corner
of trench is often very thin, sometimes may be nothing. Spray coater technology is a new resist coating technology,
which can make the resist equably distribute. The equipment we used is spin module Delta Alta Spray coater (AK
995023) produced by Suss Micro Tec. Through adjusting the parameters of the equipment, such as flux of resist, flux of
nitrogen, chuck temperature, arm speed, scan times and so on, we have obtained multifarious resist figure with diverse
thickness in order to satisfy different requirements. Now, we have already experimented three different mesa
microstructures, the resist thickness we have obtained can change from zero point five micrometer to five micrometers.
The pictures gained by scanning electronic microscope show that the resist have good uniformity, which increase the
maneuverability of exposure process which we will do next.
Quantitative measurement of screening rate by a thermal imager
Author(s):
Xiao-xia Li;
Sen Ma;
Nan Zhao;
Yu-xiang Guo
Show Abstract
Based on the characteristics of a thermal imager, a quantitative test method and operational formula of
screening rate of infrared screening materials were presented. In this method, a real mode object instead of
blackbody was used as a target, which can make the test easy and quick. The screening effect can be measure
quantitatively and visually simultaneously. The outfield experiment results conform to each other very well, that is,
the target can merge in the background at the screening rate above 85%.
Linear-mode characters of near-infrared wavelength InGaAs APDs for optical communication
Author(s):
Wei He;
Ke-ming Du
Show Abstract
Recent developments in three-dimension imaging, quantum cryptography, and time-resolved spectroscopy have
stimulated interest in Linear-Mode and Geiger-Mode detecting avalanche photodiodes operating in the short wavelength.
A linear-mode detector based on an InGaAs avalanche photodiode (APD) has been investigated for use at near infrared
communication wavelengths. In the experiments of this paper, sine gate signals coupled with DC biased voltage were
applied to two APDs with the same semiconductor material and structure for detecting the pulse light signal. As the
avalanche signals were mixed with sine wave background, a transformer-based method was applied to eliminate the
background noise and improve the detection sensitivity of light induced signal. In order to test the maximum detection
sensitivity, the sine pulse was delayed by a delay module before being applied to laser source, thus the pulse light signal
and the sine pulse coupled to the detector were synchronized. From the performance tests, the frequency response from
10MHz to 100MHz is tested and the suitable range of biased voltage was acquired. Detection sensitivity and
photoelectric gain were investigated in detail at 1.55um infrared wavelengths. In a word, the linear-mode APD working
in gate-mode and mutual-differencing method can be widely used in optical communication such as Non-line-of-sight
communication, free space communication, fiber communication, deep space communication, and satellite optical
network communication.
The different electrical responses of HgCdTe and InSb photovoltaic infrared detectors under pulsed laser irradiation
Author(s):
Xin Zheng;
Xiang-ai Cheng;
Tian Jiang;
Houman Jiang
Show Abstract
In the experiments of photovoltaic detectors illuminated by CW lasers, some new mechanism has been
found, such as power saturation of photovoltage, hot carrier effect, as well as thermovoltage effect. To
investigate whether there is similar mechanism with pulsed laser irradiating, an 808nm femtosecond
pulsed laser is adopted. In the experiments, three photovoltaic infrared detectors are used, namely short
wavelength HgCdTe detector, medium wavelength HgCdTe detector and medium wavelength InSb
detector. Actually, the 808nm pulsed laser is spectral related laser for short wavelength HgCdTe
detector while spectral unrelated laser for medium wavelength HgCdTe and InSb detector. Under
various power densities, the detectors have a series of outputs. Power saturation of photovoltage is
observed. However, the characteristics of the outputs of these three detectors are quite different, even
between medium wavelength HgCdTe and InSb detector, which have the same packing method. There
are three major contributions in the paper. Firstly, explain the mechanism of power saturation of
photovoltage, mainly from hot carrier effect and the depressed ability of PN junction to separate
electrons and holes with the higher temperature induced by the laser. Secondly, compare the differences
between medium wavelength HgCdTe and InSb detector and give a qualitative analysis. Finally, the
difference of the outputs between short and medium wavelength HgCdTe detector is compared and
qualitatively analyzed, too, with the different mechanisms of interaction between infrared detectors and
spectral related or spectral unrelated laser. The experimental results and theory analysis will show
valuable clue for future research on photovoltaic detector irradiated by pulsed laser.
Small target detection in infrared clutter using dark channel prior and improved local entropy
Author(s):
Zheng Mao;
Le-gong Sun;
Yuxin Mao;
Anjie Gao;
Yue Qin
Show Abstract
In this article, we propose an infrared background clutter suppression technique using a similar method with the haze
removal algorithm based on dark channel prior. The proposed method introduce some modifications to make the original
haze removal algorithm can work in gray-scale infrared image in real-time. In addition, after the background suppression,
we address a efficient algorithm for small target detection, which incorporate Box-Filtering technique into traditional
small infrared target detecting based on LEA. This improved method reduces a large number of redundant calculations in
traditional Local Entropy algorithm by applying the iterative operations instead of using traditional approach. We
provide detailed analysis for time complexity and the results of simulation experiments with real world infrared images
in the final of this work.
An inversion algorithm for retrieval of aerosol optical and physical properties from ground-based solar and sky radiance
Author(s):
Lili Qie;
Qingshan Xu;
Heli Wei
Show Abstract
An inversion algorithm has been developed for retrieving a set of parameters of aerosol scattering and
microphysical properties from POM02 sky-radiometer measurements. POM01/02 is the main observation instrument of
Skynet. It's designed to measure solar and sky irradiance with waveband ranging from visible to infrared, as well as the
measurement of polarization sky radiance at 870nm wavelength. Teruyuki Nakajima developed a software package to
analyze its observation data named SKYRAD.pack. SKYRAD.pack code can retrieve the columnar aerosol features,
such as optical depth, single-scattering albedo, phase function and size distribution, provided the input parameters, such
as complex refractive index and ground albedo, are correctly given. In our algorithm, most of aerosol key characteristics,
including single-scattering albedo, phase function, polarized phase function at 870nm, complex refractive index, and
size distribution, are retrieved from direct and scattered solar irradiance as well as polarized sky radiance at 870nm, by
using a polarized radiative transfer code RT3. This method requires only measurement of the aerosol's optical thickness
and an estimate of the ground's reflectance and does not need any specific assumption about properties of the aerosol.
The preliminary results are reported in the paper.
Study on infrared detection data read out technologies
Author(s):
Jian Yu;
Yongquan An
Show Abstract
Read out circuit is a critical component needed for infrared and visible light imaging system. Advances in image sensors
and microelectronics have led to the development of digital read out fabricated using deep sub micro integrated circuit
techniques. An brief review is given of the image sensor developing. Major adaptation circuit are review including
source follower, direct injection, and capacitance trans impedance amplifier. On chip analog signal processing and
analog to digital conversion techniques are also discussed. Noise shaping modulation is a promising technique to build a
low power, ultra small area, high precision pixel level AD convertor.
Study on detecting CFRP composites using pulsed infrared thermography
Author(s):
Yan Huo;
Hui-Juan Li;
Yue-Jin Zhao;
Cun-Lin Zhang
Show Abstract
Composite sandwich structure has been widely used in aerospace due to its
lightweight, high stiffness and strength. The quality of the structure is crucial to
durability and structural integrity of the rehabilitated the structure, Delaminations,
debonding and water ingressing to honeycomb are typical defects in the structure.
Defects in the structure will influence the quality of product. Pulse thermography has
been an effective NDE method in recent ten years. The technique uses pulse to excite
the specimen, because the presence of subsurface defects reduce the diffusion rate,
then temperature difference between defect area and sound area will be measured by
an infrared camera. Subsurface defects become visible with time delays, it is a
non-contact, quickly inspection method. Pulsed infrared thermography has been
widely used in aerospace and mechanical manufacture industry because it can offer
non-contact, quickly and visual examinations of defects. It is a meaningful research
topic to study on quantitative testing with the structure rapidly and non-destructively.
Sandwich composites with aluminum facesheet and aluminum honeycomb cores are
chosen as study objectives. Some back-drilled holes with different sizes and depths in
the specimen are used to simulate delaminations between plies in the strcuture .The
paper presents a method for defining the boundaries, quantitatively estimating the
sizes of the flaws in the CFRP using pulsed infrared thermography. Processing
captured data using splinefitting, measuring the size of the defects by calculating the
pixels numbers that exceed the detection threshold and computing areas of defects by
binary image. Compared with the designed sizes and areas having defects, the results
show that the method offers more than 90% accuracies with reference to the sizes of
artificial flaws embedded in the CFRP sheet. The experimental results demonstrate
the feasibility of using detection threshold to inspect the CFRP sheet. The curve of the detection threshold and depth obtained could be applied for practical inspection.
A grayscale image color transfer method based on region texture analysis using GLCM
Author(s):
Yuanmeng Zhao;
Lingxue Wang;
Weiqi Jin;
Yuan Luo;
Jiakun Li
Show Abstract
In order to improve the performance of grayscale image colorization based on color transfer, this paper proposes a novel
method by which pixels are matched accurately between images through region texture analysis using Gray Level
Co-occurrence Matrix (GLCM). This method consists of six steps: reference image selection, color space transformation,
grayscale linear transformation and compression, texture analysis using GLCM, pixel matching through texture value
comparison, and color value transfer between pixels. We applied this method to kinds of grayscale images, and they
gained natural color appearance like the reference images. Experimental results proved that this method is more effective
than conventional method in accurately transferring color to grayscale images.
Experimental study on the responsivity enhancement of Mn1.56Co0.96Ni0.48O4 detector under moderate bias field
Author(s):
Wei Zhou;
Yun Hou;
Yan Qing Gao;
Leibo Zhang;
Zhi Ming Huang
Show Abstract
As a typical thermal sensitive material, Mn1.56Co0.96Ni0.48O4 (MCN) has achieved widely applications in uncooled
bolometer. In this paper, we report that a large increase in electrical conductivity of MCN is obtained with moderate
electric-field strengths (E~103V/cm) applied at room temperature (about 300K). Great enhancement in the
responsivity is observed when operating with a proper electric bias field, which corresponds to a threshold voltage
VTh. MCN bulk materials are prepared by using the sintering method. Micro MCN detector is fabricated by scribing
the bulk material into pieces sized 200×100×10μm. The detector is clinged to an Al2O3 substrate with some electrical
insulated epoxy glue which is mounted onto a Cu sink. The surrounding temperature is controlled precisely by a
temperature controller with a precision of 1mK. Voltage-current characteristics at 270-330K are carefully examined.
Different sweeping speeds of the bias-voltage are applied in different orders so as to find out a proper scanning rate,
in which the electrical measurement is proceeded in a state of quasi-thermal equilibrium. According to quasi-thermal
equilibrium and the time dependent nominal D.C. power, the temperature increase during the measurement is
estimated. The conduction mechanism can be well explained with small polaron theory. Empirical equations are used
to describe the thermal dynamic process in the pulsed mode, and the process is also simply simulated via numerical
calculations. The experimental results and simulation works will be of some referential value to future studies in
uncooled microbolometer made in transition metal oxides.
Prediction of time to go of IR imaging GIF
Author(s):
Min-ge Fan;
Zhi-yong Peng;
Xiao-Liang Luo;
Jin Lu
Show Abstract
During the infrared imaging guided missile-target terminal impact, the remaining time estimating
accuracy plays a very important role to missile burst control. The precision of anti-aircraft missile is
sensitive to the angle-measured error by using infrared imaging GIF technology. But in theory, the
distance information can be introduced to lower the negative effect of the angle-measured error. So,
how to get missile-target distance is a key. The use of laser fuze is common solution, which but makes
the system more complexity and cost higher. The paper proposes a distance-measured method, which
the missile-target distance is obtained by using the grey value of target tracking point in successive
infrared image frame. Then the distance and angle information is integrated together to estimate the
missile-target impact time.
Infrared thermography non-destructive evaluation of lithium-ion battery
Author(s):
Zi-jun Wang;
Zhi-qiang Li;
Qiang Liu
Show Abstract
The power lithium-ion battery with its high specific energy, high theoretical capacity
and good cycle-life is a prime candidate as a power source for electric vehicles (EVs)
and hybrid electric vehicles (HEVs). Safety is especially important for large-scale
lithium-ion batteries, especially the thermal analysis is essential for their development
and design. Thermal modeling is an effective way to understand the thermal behavior
of the lithium-ion battery during charging and discharging. With the charging and
discharging, the internal heat generation of the lithium-ion battery becomes large, and
the temperature rises leading to an uneven temperature distribution induces partial
degradation. Infrared (IR) Non-destructive Evaluation (NDE) has been well
developed for decades years in materials, structures, and aircraft. Most thermographic
methods need thermal excitation to the measurement structures. In NDE of battery,
the thermal excitation is the heat generated from carbon and cobalt electrodes in
electrolyte. A technique named "power function" has been developed to determine the
heat by chemical reactions.
In this paper, the simulations of the transient response of the temperature distribution
in the lithium-ion battery are developed. The key to resolving the security problem
lies in the thermal controlling, including the heat generation and the internal and
external heat transfer. Therefore, three-dimensional modelling for capturing
geometrical thermal effects on battery thermal abuse behaviour is required. The
simulation model contains the heat generation during electrolyte decomposition and
electrical resistance component. Oven tests are simulated by three-dimensional model
and the discharge test preformed by test system. Infrared thermography of discharge
is recorded in order to analyze the security of the lithium-ion power battery.
Nondestructive detection is performed for thermal abuse analysis and discharge
analysis.
Study of PZT thick-film infrared detectors prepared by MEMS technology
Author(s):
Xiang-Peng Qiang;
Gui-Wu Chuan;
Bo-Luo Wen;
Li-Zhang Wan;
Qiang-Cao Jia
Show Abstract
In this paper, a single element integrated infrared detector using screen printed lead zirconate titanate (PZT) thick
films on Pt/Ti/Al2O3/SiO2 coated silicon cup has been developed. The thermal insulating micro-bridge of the detector
was prepared by Micro-electro-mechanical System (MEMS) technology. To increase the density of PZT ceramic thick
films, cool isostatic pressing experiments had been conducted under 300MPa and 30s dwell time. The XRD pattern
shows that PZT thick films possess good perovskite structure. The SEM cross section image demonstrate that the PZT
film was dense and the thickness is about 25μm. The dielectric constant, loss and pyroelectric coefficient of PZT thick
films prepared at optimized conditions is 1100, 1% and 1×10-8C/Kcm 2, respectively. The results indicated that the PZT
thermal sensitive layer fabricated by screen printing on the Pt/Ti coated silicon cup with micro-bridge thermal insulation
structure, and Al2O3/SiO2 barrier layer show potential application in infrared detectors.
Thermal battery infrared monitoring system design based on virtual instrument technology
Author(s):
Qin Qin;
Zheng-guo Liu
Show Abstract
This paper designs a thermal battery infrared monitoring system using FLUKE Ti45 Thermal Imagers and IMAQ
Vision software of LabVIEW. The thermal battery infrared monitoring system uses infrared imaging technology to
monitor the electrical property testing process. It can investigate and analyze the working performance of thermal
batteries on different kinds of maximum conditions, and monitor the temperature variation tendency.
Small infrared target detection algorithm based on mathematical morphology
Author(s):
Feng Jiang;
Min-hui Jin;
Li-quan Song
Show Abstract
In infrared detection, we utilize the infrared radiation emitted from target to detect and identify the target we need as
soon as possible, so we can get more reaction time for on the battlefield. However, because of the long distance between
target and the sensor, the area of the image into target is very small. Infrared small target detection has become a difficult
area of target recognition. In order to improve the accuracy of target detection,, we should preprocessing the infrared
image before identifying target, including noise reduction, background suppression and target enhancement, after that,
we can lay the foundation for the recognition processing. Firstly, we should filter the image by using median filter.
Because the median filter not only filter noise effectively (especially the impulse noise) but also maintain the goal of
good details, and the operation of this method is simple and faster. Secondly, we want to suppress the background. In
describing the signal characteristics, mathematical morphology has unique advantages, so we suppress the image
background in this way. Thirdly, after the above treatment, we can use adaptive threshold to achieve the objectives of the
segmentation, and get the binary image obtained.
Method research on the calculation atmospheric path radiation in foggy weather
Author(s):
Ji-lin Gu;
Wen-hai Xu
Show Abstract
Quantitative research of atmospheric path radiation and object reflectance radiation has been paid much attention and the
research is significant content for atmospheric correction due to spacecraft remote sensing detection further studied.
Because of the calculation for atmospheric path radiation depended on complex programs such as MODTRAN, the
programs are very difficult to understand and it will be waste most time to call them. Thus, the model for atmospheric
path radiation is set up to obtain the exact value of atmospheric path radiation fleetly and conveniently, which is helpful
for actual significance on infrared target tracking, infrared target detecting and infrared target imaging. Based on the
theory of atmospheric radiation transmission and atmospheric window, this paper comprehensively considers how to
calculate optical depth, slant path and the influence in foggy weather, and establishes complete models and calculation
method of atmospheric boundary layer atmospheric path radiation of 3~5μm. Compared the result of this MATLAB
program for the models with the result of PcModWin5, relative error is within 5%. It provides theoretical foundation for
design and evaluation of infrared systems.
An effective recognition algorithm for multiple targets under sea surface background
Author(s):
Jian-dong Wang;
Biao Zhang
Show Abstract
This paper describes an effective multiple targets recognition algorithm under the
circumstances that the targets are with a sea surface background. The proposed algorithm relies on
three steps. Firstly, an improved canny operator was adopted to get the edge characteristics of the
image templates of airplanes, naval ships and islands , compared to the classical canny operator, the
proposed canny operator can generate more accurate edges because of the anisotropic Gaussian
filtering and the self-adaptive threshold estimate method it used. Secondly, to calculate the valid
objects' positions and generate their edge binary images in the current image, region grown algorithm
and improved canny algorithm were adopted. Finally, a hausdorff distance based categorizer was
implemented to classify the objects already been located. Experimental results show that the approach
performs well in multiple targets recognition in images with sea surface background , the proposed
algorithm has strong pertinency and high efficiency to similar problems.
Denoising approach for remote sensing image based on anisotropic diffusion and wavelet transform algorithm
Author(s):
Xiaojun Wang;
Weidong Lai
Show Abstract
In this paper, a combined method have been put forward for one ASTER detected image with the wavelet filter to
attenuate the noise and the anisotropic diffusion PDE(Partial Differential Equation) for further recovering image contrast.
The model is verified in different noising background, since the remote sensing image usually contains salt and pepper,
Gaussian as well as speckle noise. Considered the features that noise existing in wavelet domain, the wavelet filter with
Bayesian estimation threshold is applied for recovering image contrast from the blurring background. The proposed PDE
are performing an anisotropic diffusion in the orthogonal direction, thus preserving the edges during further denoising
process. Simulation indicates that the combined algorithm can more effectively recover the blurred image from speckle
and Gauss noise background than the only wavelet denoising method, while the denoising effect is also distinct when the
pepper-salt noise has low intensity. The combined algorithm proposed in this article can be integrated in remote sensing
image analyzing to obtain higher accuracy for environmental interpretation and pattern recognition.
An airborne thematic thermal infrared and electro-optical imaging system
Author(s):
Xiuhong Sun;
Peter Shu
Show Abstract
This paper describes an advanced Airborne Thematic Thermal InfraRed and Electro-Optical Imaging System
(ATTIREOIS) and its potential applications. ATTIREOIS sensor payload consists of two sets of advanced Focal Plane
Arrays (FPAs) - a broadband Thermal InfraRed Sensor (TIRS) and a four (4) band Multispectral Electro-Optical
Sensor (MEOS) to approximate Landsat ETM+ bands 1,2,3,4, and 6, and LDCM bands 2,3,4,5, and 10+11. The
airborne TIRS is 3-axis stabilized payload capable of providing 3D photogrammetric images with a 1,850 pixel
swathwidth via pushbroom operation. MEOS has a total of 116 million simultaneous sensor counts capable of
providing 3 cm spatial resolution multispectral orthophotos for continuous airborne mapping. ATTIREOIS is a
complete standalone and easy-to-use portable imaging instrument for light aerial vehicle deployment. Its miniaturized
backend data system operates all ATTIREOIS imaging sensor components, an INS/GPS, and an e-Gimbal™ Control
Electronic Unit (ECU) with a data throughput of 300 Megabytes/sec. The backend provides advanced onboard
processing, performing autonomous raw sensor imagery development, TIRS image track-recovery reconstruction,
LWIR/VNIR multi-band co-registration, and photogrammetric image processing. With geometric optics and boresight
calibrations, the ATTIREOIS data products are directly georeferenced with an accuracy of approximately one meter.
A prototype ATTIREOIS has been configured. Its sample LWIR/EO image data will be presented. Potential
applications of ATTIREOIS include: 1) Providing timely and cost-effective, precisely and directly georeferenced
surface emissive and solar reflective LWIR/VNIR multispectral images via a private Google Earth Globe to enhance
NASA's Earth science research capabilities; and 2) Underflight satellites to support satellite measurement calibration
and validation observations.
A fast algorithm for wide baseline match basing on feature points filtration
Author(s):
Zhenjun Zhang;
Zhiguo Cao
Show Abstract
A fast algorithm for wide baseline image match is proposed. The algorithm mainly follows
the framework of SIFT (scale invariant feature transform) and bases on analytic signal theory. The
proposed method firstly evaluates the characteristics of feature points detected by SIFT basing on
criterions educed from Laguerre-Gauss function, and then groups all the feature points into two
sets according to their robustness and the criterions. It preserves robust feature points to
construct local descriptor and ignores the unstable ones in the later computation. Experiments
demonstrate, compared with Lowe's SIFT, that the proposed method not only decreases
computing tasks, reduces consumed time, but also improves correct match ratio. It is especially
suitable for implementation in real-time system.
A real-time restoring method for infrared images degraded by high-speed airflow
Author(s):
Qiang Mi;
Jindong Fei;
Chen Chen
Show Abstract
Restoring images degraded by low speed airflow such as atmospheric turbulence
was studied by many researchers a long time ago, and many methods were proposed. However, those
methods proposed for low speed airflow generally can't meet this urgency mainly in two aspects: first,
those methods are usually time-consuming, which fail time requisition; second, those deconvolution
models designed for low speed airflow may not suit the case of high speed airflow, which leads to bad
restoring effect. Because existent blind deconvolution methods are not competent for real-time
restoring infrared images degraded by high speed airflow, a fast restoring method for that application
is researched in this paper. Both the PSF estimation and the object estimation processes are
constructed to improve the algorithm's efficiency. The simplified Weiner filter is adopted to fast
estimate objects given PSF. For traditional methods, many computation methods, including iterative
and non-iterative ones, can be used to resolve that problem. But we are more interested in
non-iterative methods because of application background of our work, in which the speed of restoring
algorithms is also an important factor that we must be concerned about. Therefore we choose here
inverse-filtering method to estimate the object and use FFT to accelerate the computation.
Gaussian-like function is used to approximate the PSF of degradation of high speed airflow. There are
many papers on blur identification and was summarized well. However, those methods are either
iterative, leading to slow estimation, or not feasible for Gaussian-like PSF. Therefore We figure out a
new a frequency domain scheme to estimate the parameter of PSF quickly, and use both simulation and
wind tunnel experiment infrared images to test its validation. Finally we compare our algorithm with
other three blind algorithms, that is the Rechardson-Lucy method (RL), the maximum likelihood
method (ML) and the primary component analysis method (PCA), and the results show that our
algorithm not only gives much better result, but also consumes much less time.