Proceedings Volume 9142

Selected Papers from Conferences of the Photoelectronic Technology Committee of the Chinese Society of Astronautics: Optical Imaging, Remote Sensing, and Laser-Matter Interaction 2013

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Proceedings Volume 9142

Selected Papers from Conferences of the Photoelectronic Technology Committee of the Chinese Society of Astronautics: Optical Imaging, Remote Sensing, and Laser-Matter Interaction 2013

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Volume Details

Date Published: 21 February 2014
Contents: 4 Sessions, 86 Papers, 0 Presentations
Conference: Selected Proceedings of the Photoelectronic Technology Committee Conferences held July-December 2013 2013
Volume Number: 9142

Table of Contents

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Table of Contents

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  • Front Matter: Volume 9142
  • International Conference on Frontiers in Optical Imaging Technology and Application
  • International Seminar on Aerial Optical Remote Sensing Technology and Application
  • International Seminar on High-power Laser Interaction with Matter and Application
Front Matter: Volume 9142
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Front Matter: Volume 9142
This PDF file contains the front matter associated with SPIE Proceedings Volume 9142, including the Title Page, Copyright Information, Table of Contents, and the Conference Committee listing.
International Conference on Frontiers in Optical Imaging Technology and Application
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Room temperature InGaAs hot electron detector for THz/subTHz regions
Jinchao Tong, Jingguo Huang, Zhiming Huang, et al.
A THz/subTHz radiation detector based on MOCVD-grown modulation-doped InxGa1-xAs/InP structure is proposed. Devices have bow-tie metallic antennas to improve the couple efficiency about 5 dB and are fabricated with mesas of 3 μm depth by wet etching. Detection by hot electron effects under external electromagnetic radiation is explained. Measurements performed at electromagnetic wave frequency f=0.0375 THz show the detector having sensitivity about 6 V/W and noise equivalent power (NEP) about 1.6×10-9 W/Hz1/2 at room temperatures.
Biological detecting and imaging technology based on guided-mode resonance effect
Zhenyun Wang, Qi Wang, Dawei Zhang, et al.
This paper briefly introduces biological sensing based on guided-mode resonance (GMR) effect and two main application models commonly used in biomolecular sensing. The two models are GMR label-free detecting biosensor and GMR enhanced fluorescence bioimager. Using these biosensor and bioimager, the detecting limitation and imaging resolution in current researches are reviewed. We also indicate the detection results and a few achievements in our work. Some other potential applications are also described in the paper.
Characteristic research and linearity measurement of photodetectors
Hongchao Hui, Lin Yang, Xiaoping Ouyang, et al.
To accurately measure the linearity of photodetectors in near-infrared waveband, based on the beam superposition method, a new design idea which use the tow-beam path and correlation methods was proposed. Using the 1053nm laser, and the Si photodetector as the experimental subject, a linearity measurement system of highly accurate photodetectors was designed. This system has over seven orders of magnitude dynamic range. The joint uncertainty is superior to 0.08%. Meanwhile, the linear factor of four different conditions which include the different size of incident beam spots, incident angles, positions and the environment temperature have been measured and analyzed. The experiment shows that the linearity of Si photodetector is ideal when the size of beam spots are bigger, the incident angles are smaller and the environment temperature is lower, moreover, the linearity of margin area is unsatisfactory.
Detection of small targets against complex sky background based on bidirectional SVD decomposition temporal filters
Wang Hou, Haibo Liu, Xiaochun Liu, et al.
The temporal profile of the small target in the sky background and the disadvantage of traditional method are analyzed. Then we propose a novel method of small target detection based on image sequence in complex sky background. The illumination intensity is normalized firstly in image sequence. Then, the temporal matrix is decomposed using SVD in both horizontal and vertical direction. The small target is extracted in these two directions. Then, add these two images. Finally, segment the image with threshold. Obtain the trajectory of the small target in image sequence. The simulations show that our method is robust and effective.
Detection of small target using recursive higher order statistics
Wang Hou, Hongyuan Sun, Zhihui Lei
In this paper, a recursive higher order statistics algorithm is proposed for small target detection in temporal domain. Firstly, the background of image sequence is normalized. Then, the higher order statistics are recursively solved in image sequence to obtain the feature image. Finally, the feature image is segmented with threshold to detect the small target. To validate the algorithm proposed in this paper, five simulated and one semi-simulation image sequences are created. The ROC curves are employed for evaluation of experimental results. Experiment results show that our method is very effective for small target detection.
The small target detection based on maximum likelihood estimation and spot detection operator
Wang Hou, Gucan Long, Zhihui Lei, et al.
In this paper, aiming at the small target detection problem in the infrared image sequence, we propose a small target detection method based on maximum likelihood estimation and NNLoG spot detection operator. Compared with the traditional method, our proposed method can partially solve the nonlinear motion of the small target in image sequence. The real target trajectory is approximated by polynomial to enhance the signal to noise ratio of target. To validate the proposed method, we create eight experiments to simulate. The experiment result shows that our method is very valuable for small target detection.
An infrared polarization image fusion algorithm based on oriented Laplacian pyramid
Based on characteristics that infrared polarization image can restrain background noise greatly and can be more sensitive to target edge information, a polarization image fusion algorithm based on oriented Laplacian pyramid is proposed in this paper. The method is mainly used in image fusion between the infrared radiation intensity image I and degree of polarization image P in order to increase the amount of information of the image. First, each Gaussian pyramid level is decomposed in different directions to get oriented Laplacian pyramid. Second, the oriented Laplacian pyramid level images of the image I and the image P are fused with the criterion of direction gradient to get fused oriented Laplacian pyramid level images. At last, the fused image is acquired by image reconstruction. The result of experiment shows that this method could add the polarization characteristics into the original intensity image, increase the image contrast and clarity, and make the overall visual effect better.
Virtual ghost imaging with partially coherent hyperbolic cosine Gaussian beam through turbulence
Xu Yang, Yong Zhang, Lu Xu, et al.
Based on the classical optical coherence theory, a single detector virtual ghost imaging (VGI) with partially coherence hyperbolic cosine Gaussian beam has been demonstrated theoretically. An analytical imaging formula is obtained and the numerical calculation results lead to the influences of the turbulence strength, the propagation distance and the coherent parameters of the beam on the imaging quality. Moreover, we find that the VGI with hyperbolic cosine Gaussian beam can resolve the target better than the VGI with the conventional Gaussian Schell model beam under similar conditions.
Laser interfering profilometer for micro-ball whole surface measurement
Bing-hui Lu, Jian-long Zhang, Bing-guo Liu, et al.
In order to get the precise whole surface feature of micro-ball efficiently without missing points, a laser interfering measurement system and method is developed. Based on the principle of phase-shifting diffraction interference with short- coherence light source, a wave-separation interfering light path is designed, which contains single mode fiber for filtration and pin-hole reflector for diffraction. An accessory system is also projected to complete the whole micro-ball surface scanning, including negative pressure adsorption stage-group with five degree of freedom moving for micro-ball support, overturning stages, and vision monitoring mechanism. A technological process for whole surface measurement is also given. The experiment result shows that, in the case of testing light focusing on the centre of sphere, surface topographic characteristics of micro-ball can be shown clearly and directly by the distribution of interference pattern.
Quantum holography based on second-order correlation measurement
Lu Gao, Kai Kang, Hailong Lin, et al.
The quantum holography scenario with classical thermal light source based on the second-order correlation measurement is proposed. Contrastive analysis prove that the quantum holography can be carried out with classical thermal light source and entangled two-photon light source. For the second-order correlation measurement in quantum holography, the “unbalanced test system” condition must be satisfied.
An advanced time-domain projection-based registration scene based non-uniformity correction technology and the detailed hardware realization
Ning Liu, Qian Chen, Hang Qiu
In this paper, we propose a new projection-based registration scene based non-uniformity correction technology. The hardware realization of this technology in the single FPGA cored real-time system has been detailed too. As we know, many kinds of scene based non-uniformity correction algorithm have been studied and achieved great successes. However, some of them are less effective, some are too complex to realize in hardware. These problems limit their application in engineering. We concentrate on the correction effect, the amount of computation and the hardware realizability, and finally raised this technology. It has the advantage of simple calculation, fast speed and accurate results. We have already applied this technology in the real system for some particular usage.
Central obscuration effects on optical synthetic aperture imaging
Xue-wen Wang, Xiao Luo, Li-gong Zheng, et al.
Due to the central obscuration problem exists in most optical synthetic aperture systems, it is necessary to analyze its effects on their image performance. Based on the incoherent diffraction limited imaging theory, a Golay-3 type synthetic aperture system was used to study the central obscuration effects on the point spread function (PSF) and the modulation transfer function (MTF). It was found that the central obscuration does not affect the width of the central peak of the PSF and the cutoff spatial frequency of the MTF, but attenuate the first sidelobe of the PSF and the midfrequency of the MTF. The imaging simulation of a Golay-3 type synthetic aperture system with central obscuration proved this conclusion. At last, a Wiener Filter restoration algorithm was used to restore the image of this system, the images were obviously better.
Computer-generated integral imaging system based on straight line characteristics
Integral imaging (II) – is an autostereoscopic technique, which provides 3D-images that can be viewed in full parallax without special glasses. Obtaining volumetric images consists of pick up part and reconstruction. In this work we study principles of mapping process, using preliminarily generated simple object. On the assumption of mathematical principles of straight line we implemented mapping algorithm and for verification our experiment reconstructed the result.
Eliminate background interference from latent fingerprints using ultraviolet multispectral imaging
Wei Huang, Xiaojing Xu, Guiqiang Wang
Fingerprints are the most important evidence in crime scene. The technology of developing latent fingerprints is one of the hottest research areas in forensic science. Recently, multispectral imaging which has shown great capability in fingerprints development, questioned document detection and trace evidence examination is used in detecting material evidence. This paper studied how to eliminate background interference from non-porous and porous surface latent fingerprints by rotating filter wheel ultraviolet multispectral imaging. The results approved that background interference could be removed clearly from latent fingerprints by using multispectral imaging in ultraviolet bandwidth.
Fiber-coupled high power laser diode by wavelength multiplexing
Ye Ding, Yonggang Zou, Liang Jin, et al.
In this paper, the laser diode (LD) fiber coupling method based on the wavelength multiplexing technique is used. Two different wavelengths of beams from two high power laser diodes are coupled into a single multi-mode fiber via collimating, wavelength combining, focusing and coupling to achieve high efficiently high power output. The output light beam from LD is collimated by using a section of the optical fiber with a diameter of 200μm. According to the basic principle of wavelength multiplexing, the wavelength coupling device is designed. The focusing lens set is designed with the related technical data of fiber and LD. And, two diode laser beams at 808nm and 980nm, light-emitting area of 100μm×1μm, output power of 2W(CW)LDs are coupled into a multi-mode fiber by the above method, with a core diameter of 100μm and a numberical aperture (NA) of 0.22. In the current work, for 808 nm LD and 980 nm LD at a operation current of 2.5 A, the total continuous power output is 4.05 W while the continuous power output is 3.25 W for the optical fiber laser, which gives a total coupling efficiency of as high as 80%.
Integral imaging reconstruction by sampling elemental images
The amount of image data from the captured three-dimensional integral image is large and the resolution of reconstructed images by conventional computational reconstruction methods is low in Integral Imaging (II) system. To overcome these problems, a computational reconstruction method by sampling elemental images array is proposed. This method makes full use of the matching pixels in adjacent elemental images of integral imaging, thus high resolution reconstruction is realized by only using sampled elemental images. Experimental results show that the proposed method improves the resolution of reconstructed images and reduces data amount used in reconstruction. This provides certain convenience for the storage and transmission of integral images.
Conceptual design of a rotating parallel-mirror-pair interferometer
Qisheng Cai, Bin Xiangli, Qiang Fu, et al.
In the field of Fourier-transform spectroscopy, tilt and shearing problems caused by the moving components in a translational type of spectrometer reduce the quality of the interferogram dramatically. While, the spectrometer based on rotational motion can avoid these problems. In this paper, a novel rotational type of interferometer, called rotating parallel-mirror-pair interferometer (RPMPI), is presented. Its principle and properties are studied. This interferometer consists of one beam splitter, two fixed flat mirrors, and one rotating wedged parallel-mirror-pair (PMP). The optical path difference (OPD) is obtained by the rotational motion of the PMP. Factors that affect the maximum OPD include the wedged angle of the rotating PMP, the distance between the two parallel mirrors, the direction of the incident ray, and the range of rotating angle. This interferometer can operate either in swinging mode or continuous rotary mode depending on the range of the rotating angle. In swinging mode, the OPD function is linear. In continuous rotary mode, the sampling efficiency is higher and it can operate as an ultra rapid scanning interferometer.
Study and application of body shape recognition based on depth image
Yu-chong Han, Jun Qin, Yu-nong Li, et al.
Depth images have advantages of simple processing, fog penetration, and little affection by light, thus a body shape detection algorithm based on depth image was proposed to judge personnel evacuation. This study started by making body shape dataset using a depth sensor, then extracting the HOG-depth feature. The best parameters were found, including the range of gradient direction and the number of bins. Next step was to train and classify the body shape dataset using different classifiers, and gentle Adaboost algorithm based on CART weak classifiers got the best result. Then we discussed the effect of traversal method of sliding window, and found a better pixel number of every moving step. At last, the intellectualized control method under actual personnel evacuating situation was completed from the view of software implementation.
The progress of sub-pixel imaging methods
Hu Wang, Desheng Wen
This paper reviews the Sub-pixel imaging technology principles, characteristics, the current development status at home and abroad and the latest research developments. As Sub-pixel imaging technology has achieved the advantages of high resolution of optical remote sensor, flexible working ways and being miniaturized with no moving parts. The imaging system is suitable for the application of space remote sensor. Its application prospect is very extensive. It is quite possible to be the research development direction of future space optical remote sensing technology.
Lensless ghost imaging based on mathematical simulation and experimental simulation
Yanyan Liu, Biyi Wang, Yingchao Zhao, et al.
The differences of conventional imaging and correlated imaging are discussed in this paper. The mathematical model of lensless ghost imaging system is set up and the image of double slits is computed by mathematical simulation. The results are also testified by the experimental verification. Both the theory simulation and experimental verifications results shows that the mathematical model based on statistical optical principle are keeping consistent with real experimental results.
Noise model and simulation analysis of the low noise pre-amplifier of CCD camera
Zhi Chen, Yuehong Qiu, Yan Wen, et al.
The low noise video process chain design is the important guarantee of realization of CCD detection performance. While pre-amplifier locate in the front end of the video signal process of CCD camera, so the low noise preamplifier design is the important guarantee of realization of low noise CCD camera. Firstly, calculate the bandwidth and equivalent noise bandwidth of video process chain of CCD camera. Secondly, design the preamplifier circuit and build the noise model of the preamplifier. Thirdly, according to the noise model calculation the noise of the pre-amplifier. Lastly, build the noise simulation model of the preamplifier. Through theoretical calculation and PSPICE simulation result predict the noise level of the preamplifier of the CCD .The noise level of the preamplifier less than 2 electronics, it meets specification requirement.
Image registration and noise removed for infrared subpixel-shifted images
Junqi Bai, Chunguang Zhao, Xianya Wang
For infrared focal plane array sensors, imagery is degraded by a number of phenomena during signal acquisition, particularly including under-sampling and detector non-uniformity. In this paper, we propose an efficient framework which combines neural network non-uniformity correction with image registration for removing structured and non-structured noise and increasing spatial resolution. To achieve this, we sequentially improve the image quality in two steps: primarily, removing the structured and non-structured noise based on neural network theory, and achieving registration using an iterative gradient-based registration technique. Experimental results are presented to demonstrate the effectiveness of the proposed algorithm. By using our method, the shifts between acquired frames are estimated precisely and the quality of reconstructed image is improved.
Numerical modeling on carbon fiber composite material in Gaussian beam laser based on ANSYS
Ji-jun Luo, Su-xia Hou, Jun Xu, et al.
Based on the heat transfer theory and finite element method, the macroscopic ablation model of Gaussian beam laser irradiated surface is built and the value of temperature field and thermal ablation development is calculated and analyzed rationally by using finite element software of ANSYS. Calculation results show that the ablating form of the materials in different irritation is of diversity. The laser irradiated surface is a camber surface rather than a flat surface, which is on the lowest point and owns the highest power density. Research shows that the higher laser power density absorbed by material surface, the faster the irritation surface regressed.
Phase correction of image plane in holographic microscopy with equal-step phase shift
Hong-bo Zhao, Hao Zhou, Fang-fang Tai, et al.
A method which can compensate the phase curvature of image plane in equal-step phase-shifting holographic microscopy is presented. Recording two holograms before and after inserting the sample, unwrapping the numerical reconstructed images of the two holograms respectively and subtracting them each other, the corrected phase distribution of the sample is obtained. Firstly, the imaging characteristics of in-line phase-shifting holographic system in the image plane was analyzed. Secondly, onionskin cells and USAF1951 test target were recorded and reconstructed by this method. It is shown that high quality imaging of phase objects can be achieved by proposed method.
Improved orthogonal subspace projection algorithm
For traditional orthogonal subspace projection method, before performing hyperspectral image target detection, we must acquire the background spectrum vectors. However, in many cases, we cannot obtain the prior knowledge of the background spectrum accurately. And constrained energy minimization algorithm detect targets without a priori information of background spectrum, but the algorithm has a poor performance on the big target detection and cannot effectively extract the target contour. For this reason, we propose a sample weighted orthogonal subspace projection algorithm by defining the weighted autocorrelation matrix to estimation background, and then use the orthogonal subspace projection method to detect the targets. The algorithm effectively reduces the proportion of target pixels in the sample autocorrelation matrix, and has better inhibitory effect to the background. It overcomes the inherent defects of orthogonal subspace projection and constrained energy minimization, the experimental results shows better detection effect.
Analysis on temperature effect of typical structure of lens in vision measurement
Guangwen Jiang, Ziqian Wu, Zhichao Chao, et al.
When the videometric method is working during a long period, the temperature effects on cameras and lens will cause changes in optical axis, focal length and aberration coefficients, so as to influence the accuracy and reliability of measurement results. The features of typical structure of camera lens when it is applied by thermal stress are analyzed in this paper. The model of key parts of camera lens which influence the measure accuracy mostly is built firstly, then the thermal stress is calculated and the influence of thermal transmutation to the measure accuracy is analyzed. Finally, suggestion to improve the structure of camera lens is proposed.
Off-axis focusing and imaging of scaled zone plates and anamorphic photon sieves
Junyong Zhang, Liangjun Zhang, Zhaoyang Jiao, et al.
Zone plates and photon sieves can be used to focus soft X-rays and hard X-rays. Relative to the parallel plane wave incidence and focusing on the optical axis, we here present two different models to describe the other kinds of focusing properties. The former, the scaled zone plates or photon sieves are appropriate for the titled plane wave to image, which can alter the propagation direction. The latter, the eccentric elliptical zone plates or photon sieves are appropriate for the point-to-point off-axis focusing. Based on the above-mentioned models, the different algorithms are discussed in detail under the condition of different numerical apertures. Furthermore, the correctness of our model has been verified through the commercial software VirtualLAB. The obtained results can be used for the analysis, design, and simulation of different zone plates and photon sieves, meanwhile the non-coaxial characteristics can increase the flexibility of the optical system.
Real-time tracking imaging measurement of low stretched trajectory
Haiying Wu, Sanxi Zhang, Pengzu Liu, et al.
The high speed tracing imaging technique based on a scanning reflector, can realize a real-time tracking imaging measurement of the live scene. It can compensate field of view of the fixed high speed camera and scanning velocity of photoelectric theodolites. In this work, a synchronous tracking system realized by a rotating mirror is introduced. The imaging performance is analyzed in detail. The scheme to gain flight characteristics of targets is presented. A certificated test is performed and its results confirmed the feasibility of this system.
3D real-time measurement system of seam with laser
Min-shuang Huang, Jun-fen Huang
3-D Real-time Measurement System of seam outline based on Moiré Projection is proposed and designed. The system is composed of LD, grating, CCD, video A/D, FPGA, DSP and an output interface. The principle and hardware makeup of high-speed and real-time image processing circuit based on a Digital Signal Processor (DSP) and a Field Programmable Gate Array (FPGA) are introduced. Noise generation mechanism in poor welding field conditions is analyzed when Moiré stripes are projected on a welding workpiece surface. Median filter is adopted to smooth the acquired original laser image of seam, and then measurement results of a 3-D outline image of weld groove are provided.
Algorithm selective method of infrared/visual image fusion system based on air humidity
To find out the best infrared and visible fusion system of fusion algorithm which has excellent target detection characteristics in different environment, we proposed a new fusion algorithm selective rule. We also defined new concepts: fusion algorithm coefficient and the equivalent transmissivity of system. Using local-target contrast, local-target articulation to calculate fusion algorithm coefficient, we can estimate the target detection performance of fusion system when it working in different air humidity environment. Also, we make use of infrared and visible fusion system designed by ourselves to verify this method. Besides fusion algorithm coefficient, we also use subjective evaluation to evaluate the target detection performance of fusion algorithm. At last, the best algorithm or the method which is most consistent with human visual in different conditions were found. Through this work, we can provide the basis for the algorithm of choice in the fusion system.
Research on integral imaging acquisition technology based on depth information matching
Bingbing Tang, Yan Piao, Igor Dumchykov
Integral imaging is a kind of three-dimensional imaging technology, it can be used of micro-lens array recording and displaying 3d objects in the scene. Since there are many shortcomings of traditional optical methods, such as optical components manufacturing process is complex and expensive, the generated images are easily overlapped. We propose a method using computer based on depth information matching method to obtain the elemental images array, this method can quickly get higher-resolution images without distortion. In the final we have reconstructed the elemental images, and have got the original three-dimensional scene and verified the correctness of the proposed method.
Cloud and aerosol polarimetric imager
Junqiang Zhang, Jianbing Shao, Changxiang Yan
Cloud and Aerosol Polarimetric Imager (CAPI), which is the first onboard cloud and aerosol Polarimetric detector of CHINA, is developed to get cloud and aerosol data of atmosphere to retrieve aerosol optical and microphysical properties to increase the reversion precision of greenhouse gasses (GHGs). The instrument is neither a Polarization and Direction of Earth’s Reflectance (POLDER) nor a Directional Polarimetric Camera (DPC) type polarized camera. It is a multispectral push broom system using linear detectors, and can get 5 bands spectral data, from ultraviolet (UV) to SWIR, of the same ground feature at the same time without any moving structure. This paper describes the CAPI instrument characteristics, composition, calibration, and the nearest development.
Analysis and solution of the key problems in drift data processing of launch rocket
Shuhua Cui, Jun Liu, Si Shen, et al.
Since serious drift which does not reflect the actual flight condition occurs in the vertical takeoff phase processing, the data calculation is conducted and the results show that a serious system regular deviation that was not recorded in the report actually existing in certain high-speed TV measuring apparatus. The deviation variance model is established to analyze and calculate the influence of regular deviation in system on the drift of launch rocket so as to obtain the influence quantity in a quantitative way. In this paper, the system deviation compensation process is adopted to effectively correct the deviation of the measuring equipment and provide technical support for the success of missions.
Research on compressive fusion by multiwavelet transform
Senlin Yang, Guobin Wan, Yuanyuan Li, et al.
A new strategy for images fusion is developed on the basis of block compressed sensing (BCS) and multiwavelet transform (MWT). Since the BCS with structured random matrix requires small memory space and enables fast computation, firstly, the images with large amounts of data can be compressively sampled into block images for fusion. Secondly, taking full advantages of multiwavelet such as symmetry, orthogonality, short support, and a higher number of vanishing moments, the compressive sampling of block images can be better described by MWT transform. Then the compressive measurements are fused with a linear weighting strategy based on MWT decomposition. And finally, the fused compressive samplings are reconstructed by the smoothed projection Landweber algorithm, with consideration of blocking artifacts. Experiment result shows that the validity of proposed method. Simultaneously, field test indicates that the compressive fusion can give similar resolution with traditional MWT fusion.
Research on the trace detection of carbon dioxide gas and modulation parameter optimization based on the TDLAS technology
Peng Zhao, Jun Tao, Chang-rui Yu, et al.
Based on the technology of tunable diode laser absorption spectroscopy, modulation of the center wavelength of 2004 nm distributed feedback laser diode at a room-temperature, the second harmonic amplitude of CO2 at 2004nm can be obtained. The CO2 concentration can be calculated via the Beer-Lambert law. Sinusoidal modulation parameter is an important factor that affects the sensitivity and accuracy of the system, through the research on the relationship between sinusoidal modulation signal frequency, amplitude and Second harmonic linetype, we finally achieve the detection limit of 10ppm under 12 m optical path.
Progress in development of imaging polarimeter for Stokes parameter measurement
Runqiu Xia, Xia Wang, Weiqi Jin, et al.
Imaging polarimeter is one of the primary tools of state of polarizatio analysis, and it enhances the information available in variety of applications. The foundations of polarimeter are discussed. Two classes of typical imaging polarimeters are reviewed, including division of time polarimeters and simultaneous measurement polarimeters. Both of the classes are subdivided in to several kinds of polarimeters, characteristics of them are discussed. Our current work on imaging polarimeter is revealed at last.
Coherent CdTe terahertz source for high-resolutional imaging
Jingguo Huang, Jinchao Tong, Zhiming Huang, et al.
Coherent terahertz generation is achieved in CdTe crystal at room temperature under the collinear difference frequency generation mechanism. This coherent terahertz source is pumped by the ns pulsed Nd:YAG Laser (1064 nm) and the tunable optical parametric oscillation (OPO 1050-1080 nm ) with the terahertz wave range 107.4 -381.9 μm and peak power of ~ 0.5 W. The emitted THz wave is continously tuned from 109.6 μm to 373.7 μm when the signal wavelength from OPO is changed from 1067.6 nm to 1074.9 nm. When the OPO signal wavelength is tuned from 1054.0 - 1061.6 nm, a terahertz wavelength region (107.4 - 381.9 μm) is achieved in the experiment. Compare with other terahertz sources like GaSe THz sourec or terahertz parametric generation source, this terahertz source is extreamly suited for the high-resolutional THz imaging application due to the simple way of the THz wavelength tunability.
Methods of foreign fiber detecting based on PCA analyzing of infrared spectral images
LiXun Tian, WeiSen Fu, JieYu Liu, et al.
A set of near infrared high resolution spectral imaging system is set up, the infrared absorption properties of raw cotton and colorless foreign are analyzed through the system, and scheme of polypropylene fiber detection based on the near infrared spectral image is proposed; On this basis, reduce dimensions the spectral images through the principal component analysis, further improve the efficiency of colorless foreign detection. The experimental results show that the spectral images after reducing dimensions can be used to detect colorless or light color raw cotton fiber effectively.
Wide spectral range imaging acousto-optic turnable filter used in outer space probe
Zehong Zhang, Liangqiu Wang, Xiaoliang He, et al.
This article introduces a wide spectral range imaging acousto-optic turnable filter made of two transducers. “Mismatch rate” was firstly put forward to represent the degree to which the impedance mismatch and a three stage matching circuit was designed for the filter to improve its spectral range and operating bandwidth. Now the spectral range is from 0.4μm to 1.1μm, the overall operating bandwidth reaches 1.14 octave, the diffraction efficiency over 60%, spectral resolution from 1.3nm to 7.5nm. To get rid of “ tin pest”, alloy material was used to make bonding layer material instead of pure tin, making the storage temperature of the acousto-optic turnable filter ranges from -65 °C to 85 °C, and the operating temperature from -35 °C to 70 °C.
An algorithm of rapid extraction star point and diffuse plaque in star image
Shuai Wang, Yingchun Li, Lin Du, et al.
In order to solve the low speed and low accuracy in exacting star point which used in starlight star point navigation, this paper presents an algorithm to quickly extract the coordinates of the Navistar in the image. First of all, this algorithm extracts the coordinates of star point with a low accuracy, then extracting its diffuse plaque, in the final, get its exact coordinates. Which can reduce the amount of computation to improve navigation extraction rate while avoid the time-domain filtering of the star point of the outline and diffuse spots of gray value, solving low speed in the sky diffuse plaques star point image extraction. The experiments show that this algorithm can extract the star point while making dark star and background noise greatly reduced. At the same time, star point and diffuse plaque contour gray value can be consistent with the original image.
Design and implementation of range-gated underwater laser imaging system
A range-gated underwater laser imaging system is designed and implemented in this article, which is made up of laser illumination subsystem, photoelectric imaging subsystem and control subsystem. The experiment of underwater target drone detection has been done, the target of distance 40m far from the range-gated underwater laser imaging system can be imaged in the pool which water attenuation coefficient is 0.159m-1. Experimental results show that the range-gated underwater laser imaging system can detect underwater objects effectively.
Defects in undoped semi-insulating InP
Yan Chen, Xin Guo
This paper, the electron irradiation-induced defects in undoped InP has undergone a high-temperature annealing in iron phosphide ambience. The positron annihilation lifetime spectroscopy (PAL) and thermally stimulated current spectroscopy (TSC) have been employed to study it . The results proved that, the defects in SI-InP after electron irradiation increases and the complex defects are formed . The positron mean lifetime increases about 18 ps , and more defect peaks are also found in the TSC after irradiation.
Splash generation and evolvement in the laser ablation with liquid working substance
Jifei Ye, Yanji Hong, Nanlei Li
Splash generation and evolvement have been observed with ns-shadowgraphy time resolved method on the laser micro ablation with liquid working substance. The flow visualization method of splash phenomenon is introduced and the shock wave and particle front velocity were measured and analyzed to research the relationship between material characteristics and splash dynamics. Three different laser energy densities and four different doped mass fractions are adopted for the comparison to find out the energy intensity density and work substance doped mass fraction influence on the splash generation and evolvement. The results show that: the carbon doped in the liquid working substance could weaken the splash process with the smaller droplets and shorter duration time.
The simulation of natural low level light under lab’s condition
Wanyi Lin, Jinsong Wang, Xuan Wang, et al.
Considering the needs of glimmer night vision system experiment, this paper has analyzed the working environment of glimmer night vision system, and based on this analysis the paper adopted double integrating sphere and collimator to simulate natural shimmer environment under the laboratory condition. By further analysis, we can conclude that as long as the field of collimator is larger than the field of night vision system, the natural micro light of night vision system testing can be simulated under the laboratory conditions, And the feasibility of this method is verified by experiment.
International Seminar on Aerial Optical Remote Sensing Technology and Application
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Endmember extraction algorithm for hyperspectral image based on PCA-SMACC
Chang Liu, Junwei Li, Guangping Wang
Due to the high hyperspectral data volume, high dimensionality and the data itself having great redundancy, the accuracy of Sequential Maximum Angle Convex Cone (SMACC) endmember extraction algorithm is low. In view of this, we proposed an endmember extraction algorithm based on PCA-SMACC. First , it uses principal component analysis(PCA)algorithm to achieve the purpose of hyperspectral data dimensionality reduction. The method removes the data redundancy while maintains the validity of the data. Then it uses SMACC endmember extraction algorithm on the resulting principal component images. The experimental results show that PCA-SMACC algorithm can compensate for the lack of traditional algorithms. Compared with PPI and SMACC algorithms, PCA-SMACC has improved to some extent in the extraction accuracy and speed.
The acquisition of land cover information using three indexes and TM Image
Shiwei Li, Zhaoba Wang, Jason Yang, et al.
To get the typical land cover information of urban area, present a method to get four typical land covers in study area by displaying three binary index images in RGB coordinate system without any algorithms. One scene Landsat TM image was used to calculate Normalized Difference Vegetation Index (NDVI), Negative Normalized Difference Vegetation Index (NNDVI) the paper present, and extract water information based on the spectral relationship of typical land objects. After compared the digital number of the typical land cover information of water, vegetation, impervious surface and soil in the three calculated layer, the four typical land cover information showed obvious differences. With carefully selecting appropriate threshold value for each index image, we obtained three binary images for water, vegetation and impervious surfaces. Then they were stacked to one image and assigned red to impervious surfaces, blue to water, and green to vegetation in a false color composite, and because the soil’s digital number was zero in the three binary images, it was shown black color automatically. Two hundred sample points were randomly selected for an accuracy assessment using high resolution ZY-3(China) image obtained at almost the same time as reference. The overall accuracy of the classification is 86% with the Kappa coefficient of 0.802. The result indicates that the method presented in this paper is feasible.
The polarisation correction for space-borne grating spectrometers
Fa-cai Zhao, Quan-she Sun, Kun-feng Chen, et al.
Satellite measurements of backscattered sunlight contain essential information about the global distribution of atmospheric constituents. Light reflected from the Earth’s atmosphere is linearly or partially linearly polarized because of scattering of unpolarized sunlight by air molecules and aerosols. In the ultraviolet and visible part of the spectrum, measurements of space-borne grating spectrometers are in general sensitive to the state of polarization of the observed light. The interaction of polarized light with polarization-sensitive optical devices yields a different radiance that is measured by the detectors than the radiance that enters the instrument. In the OMI and the SBUV/2 instruments the problem of instrument polarization sensitivity is avoided because the polarized backscattered sunlight is depolarized before it interacts with the polarization-sensitive optical components. For GOME, SCIAMACHY, and GOME-2 it is intended to eliminate the polarization response of the instrument from the polarization-sensitive measurement. This paper discusses the basic concept of the polarisation correction of the space-borne grating spectrometers by using Mueller matrix calculus. A model was developed using the Mueller Matrices formulation to evaluate the polarization sensitivity of the space-borne grating spectrometers. The optical components are treated as general diattenuators with phase retardance. The correction for this polarization sensitivity is based on broadband polarization measurements. Accurate preflight polarisation calibration of space-borne grating spectrometers is essential for the observational objectives of the instrument, and a special facility has been developed in order to allow the instrument to be calibrated.
A method of using commercial virtual satellite image to check the pattern painting spot effect
Zheng-gang Wang, Qing Kang, Zhi-qiang Shen, et al.
A method of using commercial virtual satellite image to check the pattern painting spot effect contrast with the satellite images before painting and after painting have been discussed. Using a housetop as the testing platform analyses and discusses the factors’ influence such as resolution of satellite image, spot size and color of pattern painting spot and pattern painting camouflage method choosing to the plan implement. The pattern painting design and spot size used in the testing has been ensured, and housetop pattern painting has been painted. Finally, the small spot pattern painting camouflage effect of engineering using upon painting pattern size, color and texture have been checked, contrasting with the satellite image before painting and after painting.
Electronics design of the airborne stabilized platform attitude acquisition module
Jiang Xu, Guiling Wei, Yong Cheng, et al.
We present an attitude acquisition module electronics design for the airborne stabilized platform. The design scheme, which is based on Integrated MEMS sensor ADIS16405, develops the attitude information processing algorithms and the hardware circuit. The hardware circuits with a small volume of only 44.9 x 43.6 x 24.6 mm3, has the characteristics of lightweight, modularization and digitalization. The interface design of the PC software uses the combination plane chart with track line to receive the attitude information and display. Attitude calculation uses the Kalman filtering algorithm to improve the measurement accuracy of the module in the dynamic environment.
The research and application of medium resolution remote sensing images in the city information extraction
Feihong Wang, Jason Yang, Shiwei Li, et al.
In order to obtain urban distribution, the decision tree classification technology is used to classify remote sensing image in the study area. Landsat TM image ,digital elevation model (DEM), and normalized water index, vegetation index and cultivated land index as well as image spectral statistical characteristics and space information characteristics are used.Through the threshold determination methods, decision tree is built to achieve a classification of six kinds of objects in the study area ,which are water body, artificial structure, bare land, cultivated land, forest land and grassland. Finally confusion matrix is used to evaluate classification results, the overall classification accuracy of the decision tree is 89.52%, the Kappa coefficient is 0.867.
Land use changes and its impact on land surface temperature of Yancheng City from 2000 to 2009 analysis
In the paper, based on the technology of remote sensing and geographic information system, and according to the Landsat TM images obtained the land use database and land surface temperature of Yancheng city in the year of 2000 and 2009. Five land use types were identified, namely: farmland, building site, forest and grassland, water, and beach wetland. And then analysis of the urban expansion model based on the Defense Meteorological satellite data. The results show that: (1) In the five kinds of land use types, the largest rate of land use change is beach wetland, which is -8.23, followed by water as -5.17, forest and grassland is 3.27, building site is 2.24, farmland is 0.69. (2) During the 2000-2009, the towns of Yancheng city continuous outward expansion. In the old town, the expansion model is similar to the concentric circles spread to the periphery, but in the new district, which mainly concentrated in the northeast and southeast, the expansion model is re-planning, development and construction. (3) The land use structure change, especially the changes of beach wetland have a largest influence on the land surface temperature of Yancheng city. Among them, the average land surface temperature has increased over 8 degrees. However, the farmland change due to the overall land surface temperature decreased. And the increase of building site, making the urban heat island effect has been enhanced, while the town where the land surface temperature increases in value added in 0 to 5 degrees. At the same time, the water changes, this due to the land surface temperature increases and the added value in the range of 5 to 8 degrees.
Error correction of photoelectric rotary and angle encoder
Liang Zhou, Wen-ji She, Jing Huang
The photoelectric rotary and angle encoder is a digital angle measuring device, which is integrated with optics, mechanics and electrics. Because of its simple structure, high resolution, and high accuracy, it has been widely used in precision measurement of angle, digital control and digital display system. With the needs of fast tracking and accurate orientation on the horizon and air targets, putting forward higher requirements on accuracy of angle measurement and resolution of photoelectric rotary and angle encoder. Influences of manufacturing, electronics segmentation, optical and mechanical structure and eccentric shaft to photoelectric encoder precision and reducing methods are introduced. Focusing on the eccentricity error, building up an error correction model to improve the resolution of angle encoder and the model was verified by test.
The precision analysis of continuous zoom lens in airborne electro-optical pod
Xiao-xu Yang, Da-wei Li, Jun-feng Han, et al.
In the research of electro-optical pod, this paper propose a mission requirements that continuous zoom lens system is using for measuring angle in the process. This paper analyzes the influence of angle measurement accuracy from focal length and optical axis errors in the process of continuous zoom, and given the mathematical model of the influence of angle measurement accuracy. The simulation analysis indicated that Angle measuring accuracy is affected by the process of continuous zoom. The simulation analysis results have certain instructive significance to engineering practice.
Target location in aerial image by fast NCC
Target location is a fundamental application in aerial image process. In this work, a fast normalized cross correlation algorithm is proposed for the application of target location in aerial image. Firstly, normalized cross correlation has been proved equivalent to Euclidean distance. In the search step, the target template and the corresponding window of base image are projected to a set of mutually orthonormal vectors for calculating the lower bound of the distance, where the windows with too large distance relative to the target template will be rejected in this step. Finally, the directly normalized cross correlation calculating is applied to the rest windows of base image to achieve the final correct location of target. The experimental results show that compared with traditional method, the proposed method significantly improved the computational complexity without sacrificing the spatial resolution or the accuracy of the match result.
SAR image registration based on SIFT and MSA
Zhaoxiang Yi, Xiongmei Zhang, Xiaodong Mu, et al.
Referring to the problem of SAR image registration, an image registration method based on Scale Invariant Feature Transform (SIFT) and Multi-Scale Autoconvolution (MSA) is proposed. Based on the extraction of SIFT descriptors and the MSA affine invariant moments of the region around the keypoints, the feature fusion method based on canonical correlation analysis (CCA) is employed to fuse them together to be a new descriptor. After the control points are rough matched, the distance and gray correlation around the rough matched points are combined to build the similarity matrix and the singular value decomposition (SVD) method is employed to realize precise image registration. Finally, the affine transformation parameters are obtained and the images are registered. Experimental results show that the proposed method outperforms the SIFT method and achieves high accuracy in sub-pixel level.
Polarization measurement through combination polarizers
Yunfeng Bai, Linjun Li, Zhelong He, et al.
Polarization measurement approaches only using polarizer and grating is present. The combination polarizers consists of two polarizers: one is γ degree with the X axis; the other is along the Y axis. Binary grating is covered by the combination polarizers, and based on Fraunhofer diffraction, the diffraction intensity formula is deduced. The polarization state of incident light can be gotten by fitting the diffraction pattern with the deduced formula. Compared with the traditional polarization measurement method, this measurement only uses polarizer and grating, therefore, it can be applied to measure a wide wavelength range without replacing device in theory.
Effects of stitching pattern on diffractive telescope image quality
ZhouFeng Zhang, YongJun Xie, FuZeng Kang, et al.
Diffraction image technology is an updated technology. It has more potential for developing the larger aperture and lightweight telescope than the conventional refractive and reflective optics. In order to develop a large aperture diffractive telescope, the key is to solve the problem of large aperture lens stitching. Different stitching patterns have different effects on the image quality. However, the stitching pattern for diffractive telescope is different from the conventional refractive and reflective telescope. This paper, for the first time, studies the theory of stitching pattern for diffractive telescope. On the basis of theoretical analysis, a long-wavelength infrared diffractive telescope of segmented-lens is designed and for the first time, good results through stitching experiments have been achieved. According to theoretical analysis and experiment verification, the paper gives the best stitching pattern on diffractive telescope.
Analysis the application of several denoising algorithm in the astronomical image denoising
Chao Jiang, Ze-xun Geng, Yong-qiang Bao, et al.
Image denoising is an important method of preprocessing, it is one of the forelands in the field of Computer Graphic and Computer Vision. Astronomical target imaging are most vulnerable to atmospheric turbulence and noise interference, in order to reconstruct the high quality image of the target, we need to restore the high frequency signal of image, but noise also belongs to the high frequency signal, so there will be noise amplification in the reconstruction process. In order to avoid this phenomenon, join image denoising in the process of reconstruction is a feasible solution. This paper mainly research on the principle of four classic denoising algorithm, which are TV, BLS - GSM, NLM and BM3D, we use simulate data for image denoising to analysis the performance of the four algorithms, experiments demonstrate that the four algorithms can remove the noise, the BM3D algorithm not only have high quality of denosing, but also have the highest efficiency at the same time.
Yellow River Estuary typical wetlands classification based on hyperspectral derivative transformation
Xiaopeng Wang, Jie Zhang, Guangbo Ren, et al.
The first-order derivative transformation was applied on a PROBA CHRIS hyperspectral remote sensing image of the Yellow River Estuary coastal wetland. Five classic supervised classification methods were employed on the images before and after the derivative transformation, and then those classification results were compared through manual interpretation and quantified analysis. The aim of this research is to evaluate the effects on the classification ability of supervised classification methods made by the derivative transformation. Experimental results show that, the derivative transformation is capable of improving the classification ability of certain supervised classification algorisms in coastal wetlands classification using hyperspectral images. Especially, for the Maximum Likelihood and Support Vector Machine methods, with the best classification accuracy, derivative transformation could effectively help distinguish vegetation and clear water wetlands.
Applied low dimension linear manifold in hyperspectral imagery anomaly detection
Zhiyong Li, Liangliang Wang, Siyuan Zheng
In this paper, a new approach of anomaly detection based on low dimensional manifold will be elaborated. Hyperspectral image data set is considered as a low-dimensional manifold embedded in the high-dimensional spectral space, and this manifold has special geometrical structure, such as Hyper-plane. Usually, the main body of this manifold is constituted by a large area of background spectrum while the anomalistic objects are outside of the manifold. Through the analysis of the geometrical characteristics and the calculation of the appropriate projection direction, anomalistic objects can be separated from background effectively, so as to achieve the purpose of anomaly detection. Experimental results obtained from both the ground and airborne spectrometer data prove effectiveness of the algorithm in improving the detection performance. Since there are no available prior target spectrums to provide proper projected direction, the weak anomalies which have subtle differences from the background on the spectrum will be undetected.
Infrared and visible sequential images registration based on the motion characteristics
Zhong-zhong Xu, Zhi-hua Huang, Zhi-qiang Chi
The research has been done on how to deal with the correspondences of sequential images, and the difficulties caused by multi-sensor. The paper proposes and realizes the registration methods addressing visible and infrared sequences, and the experiments show the validity and the accuracy of the proposed methods. At the first, the research on the sequence-to-sequence rough registration by their mass centers is studied. In the method, we represent the trajectory in the form of curves, and then use the curve-matching method to match the trajectories, and finally acquire the correspondence of the two sequences both in time and space. Then, compared to the rough matching methods above, an automatic visual–infrared image sequence accurate registration method based on Co-motion and the RANSAC algorithm with the RSCJ algorithm for higher efficiency are proposed.
Study of sensing properties and contrastive analysis of metal coating optical fiber grating
Jing Wang, Ning Wang, Bin Shi, et al.
Optical fiber grating (FBG) has been widely used in the measurement of parameters such as temperature and strain. However, FBG is too slim to broken, whose outside protective layer tends to shedding easily, and it is also hard to change the temperature and strain sensitivity. In order to overcome the above disadvantages and to further expand the application range of FBG, this paper improves the technology of fiber grating metal film plating process firstly. It adopts a compositive method including chemical plating and electroplating to gild FBG, copper FBG and galvanize FBG, which all get good metal coating. Then, the temperature and strain sensing properties of metalized FBG is studied in detail. Multiple metal coating FBGs were put in high-low temperature test-box together, and then the test-box worked continuously at the temperature range of 0°C~95°C. After several experiments, it concludes that metal plating enhances the temperature sensitivity of fiber grating, and the one with galvanization has the highest temperature sensitivity of 0.0235. At last, FBGs with various cladding were pasted on carbon fiber cantilever beam respectively and the pressure on the top of the cantilever increased gradually. The experimental results show that wavelength of fiber grating shift toward the long wavelength with the increase of the pressure, and the one with galvanization has the maximum strain sensitivity which has minimal impact on fiber properties.
Research on compressive fusion for remote sensing images
Senlin Yang, Guobin Wan, Yuanyuan Li, et al.
A compressive fusion of remote sensing images is presented based on the block compressed sensing (BCS) and non-subsampled contourlet transform (NSCT). Since the BCS requires small memory space and enables fast computation, firstly, the images with large amounts of data can be compressively sampled into block images with structured random matrix. Further, the compressive measurements are decomposed with NSCT and their coefficients are fused by a rule of linear weighting. And finally, the fused image is reconstructed by the gradient projection sparse reconstruction algorithm, together with consideration of blocking artifacts. The field test of remote sensing images fusion shows the validity of the proposed method.
The remote sensing image matching based on SURF algorithm
Yonghao Hu, Bangjun Li, Liping Shi
Through the simultaneous photography technology of multi-spectral camera, the remote sensing image is composed of the different spectral of scenes’ electromagnetic spectrum. Having multi-spectral characteristics and rich image information, the remote sensing image is now used widely in many occasions. At the same time, how to achieve the remote sensing image matching rapidly and accurately has been becoming a research focus in the image processing filed. To improve the matching accuracy, this paper, based on the SURF algorithm, uses the Mahalanobis distance affine-invariant character and gets rid of the initial wrong matching points. Numerous experiments were carried out on remote sensing images with geometric distortion such as scale, rotation and so on. The result shows that the effectiveness of the method.
FPGA implementation of real-time digital image stabilization
In order to overcome image shakes in the video of the camera mounted on a movable platform and to implement the image stabilization in real-time, a FPGA platform of real-time digital image stabilization (DIS) based on bit-plane matching was realized. Firstly, the local motion vectors were estimated by using Gray Code bit-plane matching. Then, the global motion vector was generated with a median filter method. Following that, a low pass filter was applied on the previous global motion vectors to get the current motion compensation vector. At last, the stabilized video was obtained by compensation the original one. A multi-bits concurrent matching method was used when estimating the local motion vectors using the bit-plane, which increased the parallelism of the FPGA and speeded up the matching velocity. The FPGA implementation of the function modules of video capture control, image buffering, motion estimation, motion filtering, and motion compensation were detailed out. The experiment results indicate that the proposed method can stabilize the 25 fps video with 720×576 pixels in real-time, and can be applied in real-time applications.
Laser image denoising technique based on multi-fractal theory
Lin Du, Huayan Sun, Weiqing Tian, et al.
The noise of laser images is complex, which includes additive noise and multiplicative noise. Considering the features of laser images, the basic processing capacity and defects of the common algorithm, this paper introduces the fractal theory into the research of laser image denoising. The research of laser image denoising is implemented mainly through the analysis of the singularity exponent of each pixel in fractal space and the feature of multi-fractal spectrum. According to the quantitative and qualitative evaluation of the processed image, the laser image processing technique based on fractal theory not only effectively removes the complicated noise of the laser images obtained by range-gated laser active imaging system, but can also maintains the detail information when implementing the image denoising processing. For different laser images, multi-fractal denoising technique can increase SNR of the laser image at least 1~2dB compared with other denoising techniques, which basically meet the needs of the laser image denoising technique.
Research on distribution characteristic of sky background luminance
Weifeng Liu, Xiwen Qiang, Yong Wang
Since sky background luminance is a critical parameter of atmospheric optics, it is very important for space target detection and identification. In order to acquire sky background luminance characteristic and evaluate the detecting and tracking capability of electro-optical systems for space target. Sky background luminance was measured with sky background measurement equipment in somewhere in Xinjiang. The contour distribution of all-sky background luminance in different type weather was given. Experimental data measured in fact was analyzed. The distribution characteristic of sky background was acquired, That provided important basis for researching sky background luminance, arraying electro-optical system and application of related field.
Micro biochemical sensor based on SOI planar optical waveguide
A novel biochemical sensor based on planar optical waveguide is presented in this paper. The features of the sensor are as follows, the planar optical waveguide is made of SOI (Silicon-On-Insulator) material, a Mach Zehnder (M-Z) Interferometer structure is adopted as the sensing part, the sensor chip is fabricated using CMOS compatible technology and the size of the sensor chip is on the micron scale. Compared with the traditional biochemical sensors, this new type of sensor has such notable advantages as miniaturization, integration, high sensitivity and strong anti-interference capability, which provide the sensor with potential applications where traditional biochemical sensors cannot be used. At first, the benefits of SOI material comparing to other optical waveguide materials were analyzed in this paper. Then, according to the optical waveguide mode theory, M-Z interferometer waveguide was designed for the single mode behavior. By theoretical analysis of the radiation loss in the Y-junction of the planar waveguide interferometer, the relationship between the branch angle and the radiation loss was obtained. The power transfer function and the parametric equation of sensitivity of the M-Z interferometer were obtained through analysis of the waveguide structure. At last, the resolution of the effective refractive index and the characteristics of sensitivity of the sensor based on SOI M-Z Interferometer waveguide were simulated and analyzed by utilizing MATLAB software. As a result, the sensitivity of SOI M-Z Interferometer sensor can reach the order of 10-7 magnitude.
Study on full-polarization hyperspectral imaging technology
Xiangyu Wei, Qiang Zhou, Tenghui Zhong, et al.
Since full-polarization parameter measurement can not be well combined with hyperspectral imaging technology yet , a new full-polarization hyperspectral imaging measurement structure using a dual optical path system was investigated. We utilized the hyperspectral1 interference imaging technology and polarization modulation technology based on electro-optic effect in our research. The polarization information, spectral information and spatial image information were acquired at the same time, which means the simultaneous measurement of hyperspectral information and full-polarization parameter was achieved. In this artical, the principle of the full-polarization parameter measurement was introduced at first. Then the experiment setup was shown and the optical elements were illustrated. Also,the detailed formula derivation steps of the full-Stokes vector was given. At last, some computer simulation data and experimental results were given. Through the combination of spectral imaging and full-polarization parameter measurement, the detecting information of the object is greatly enriched. This work will definitely be helpful to many optical remote sensing technology areas such as resources survey, environmental monitoring and military reconnaissan.
Measurement and analysis of atmospheric optics parameters In northwest ward
Gang Sun, Ning-quan Weng, Qing Liu, et al.
When light-wave propagates in the turbulent atmosphere, it will be affected by atmospheric turbulence and brought various effect , such as flicker, phase fluctuation. So the investigation of atmosphere optics parameters always must be important. Because of the differences in geographical conditions and climate, atmospheric optical parameters in different regions have different spatial and time distribution. In this paper, various atmosphere optics parameters are measured by atmosphere optics parameters measure system in the Delingha area of Qinghai province and Xinjiang Korla area, through statistical analysis of atmospheric optical parameters corresponding area, we know clearly different geographical climate character of the northwest area of atmospheric optical parameters of structure characteristics, the results provide a valuable reference for further practical engineering application of optical remote sensing location and atmospheric optical transmission and atmospheric properties.
The analysis of distribution of meteorological over China in astronomical site selection
The distribution of parameters such as sunshine hours, precipitation, and visibility were obtained by analyzing the meteorological data in 906 stations of China during 1981~2012. And the month and annual variations of the parameters in some typical stations were discussed. The results show that: (1) the distribution of clear days is similar to that of sunshine hours, the values of which decrease from north to south and from west to east. The distributions of cloud, precipitation and vapor pressure are opposite. (2) The northwest areas in China have the characteristic such as low precipitation and vapor pressure, small cloud clever, and good visibility, which are the general conditions of astronomical site selection. (3) The parameters have obvious month variation. There are large precipitation, long sunshine hours and strong radiation in the mid months of one year, which are opposite in beginning and ending of one year. (4) In the selected stations, the value of vapor pressure decreases year by year, and the optical depth is similar or invariable. All the above results provided for astronomical site selection.
Development of a digital solar simulator based on full-bridge converter
Chen Liu, Jian Feng, Zhilong Liu, et al.
With the development of solar photovoltaic, distribution schemes utilized in power grid had been commonly application, and photovoltaic (PV) inverter is an essential equipment in grid. In this paper, a digital solar simulator based on full-bridge structure is presented. The output characteristic curve of system is electrically similar to silicon solar cells, which can greatly simplify research methods of PV inverter, improve the efficiency of research and development. The proposed simulator consists on a main control board based on TM320F28335, phase-shifted zero-voltage-switching (ZVS) DC-DC full-bridge converter and voltage and current sampling circuit, that allows emulating the voltage-current curve with the open-circuit voltage (Voc) of 900V and the short-circuit current (Isc) of 18A .When the system connected to a PV inverter, the inverter can quickly track from the open-circuit to the maximum power point and keep stability.
Scintillation analysis for multiple uplink Gaussian beams in the presence of beam wander
For a beam from ground to space, the main optical turbulence effects are scintillation and beam wander. Multiple incoherent beams can reduce the scintillation. The scintillation is determined by the number of the beams, the beam separation and the size of the beam wander variance. A wave optics simulation was applied to study the scintillation index of 1-, 3, 6 collimated uplink Gaussian beams, where a hexagonal close-pack spacing is used. Based on the results of simulations, we propose an approximation to average spatial correlation in terms of the beam separation in the tracked and untracked cases. The relation between scintillation index and beam separation is different in the weak and moderately-strong fluctuation regimes when the number of beams is the same. And the average spatial correlation is determined by the beam waist radius, beam separation and beam wander variance.
The research of cat-eye target laser active detection system performance
Zhao-fei Hou, Ying-chun Li, Shuai Wang
In order to study the performance of the cat-eye target laser active detection system, the cat-eye target laser active detection system which includes the technology of laser emitting/receiving, data acquisition, signal processing and recognition has been established. The effective reflection area of cat-eye target and the operating range function have been given. The paper focuses on the analysis of the key indicators such as laser divergence angle, laser incident angle and focal shift, which have a great impact on the operating range. According to the calculation and the simulation, it shows that in the case of oblique incidence and focal shift, the effective reflection area of cat-eye target will change; the laser beam incidence angle, focal shift and laser divergence angle of the system will have a great impact on the operating range.
International Seminar on High-power Laser Interaction with Matter and Application
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Infrared smoke field testing system based on computer calculation
Runze Tang, Shichuan Li, Yuling Cui, et al.
In order to study the infrared smoke interference performance in the field experiment, a set of infrared smoke testing system is introduced and discussed. The System works during the whole process of observation, from the smoke formation to its dissipation. According to the thermal image, the system could evaluate the interference performance of smoke screen to the target through computer calculation on Matlab program.
Influence of ellipticity in coherent soft x-ray harmonic generation from atoms and molecules
Yuanqin Xia, Faming Lu, Sheng Zhang, et al.
We experimentally study high harmonic generation from elliptically polarized femtosecond laser pulses. The harmonic intensity as a function of laser ellipticity is measured. We show that the atomic ellipticity dependence is stronger than the molecular dependence.
Theoretical investigation of output features of a diode-pumped rubidium vapor laser
In the recent years, diode-pumped alkali lasers (DPALs) have been paid many attentions because of their excellent performances. In fact, the characteristics of a DPAL strongly depend on the physical features of buffer gases. In this report, we selected a diode-pumped rubidium vapor laser (DPRVL), which is an important type among three common DPALs, to investigate how the characteristics of a DPRVL are affected by different conditions. The results signify that the population ratio of two excitation energy-levels are close to that corresponding to thermal equilibrium as the pressure of buffer gases and the temperature of a vapor cell become higher. It has been found that quenching of the upper levels cannot be simply ignored especially for the case of weak pump. The conclusions are thought to be helpful for the configuration design of an end-pumped DPAL.
Simulation and analysis of scattering characteristics for Gaussian beam and plane beam
Lian-fen Wang, Yi-ming Bi, Xuan-Ke Zhao, et al.
The scattering characteristics of a Gaussian laser beam and plane beam through spherical particle were studied. The incident field and scattering field of the Gaussian beam are expressed in spherical harmonic function, it’s expansion coefficient expression is given. Using of Matlab programming calculation, we simulate the spherical particle scattering intensity for two light beams, The results of the simulation are discussed, and the comparative analysis to plane wave scattering law were made. Results show that the scattering intensity distribution of Gaussian beam is different from the plane wave scattering law,. But under the condition of big waist radius, the scattering laws have a lot in common with the plane wave.
Research on rail surface non-touch statistic and dynamic measuring technique
Zong-qi Bi, Lian-fen Wang, Ai-fang Wang
On the basis of laser displacement sense principle, one non-contact rail surface sense measuring program is designed. Surface measuring instrument is made. Inspection and measuring for the single-section of rail surface are carried on and data-based image formation is given. The precise measuring is realized for rail surface, especial trail parts; By using the stepper motor diving technique and program operating imagine formation technique, combining the MTLAB programming, the single-surface measurement data is transformed into image and the dynamic measuring for rail vertical smoothing is achieved. By comparing to the standard data, the rail wear state and surface parameters are concluded .This technique met with the needs of non-touch automatic measuring for rail surface.
BPM analysis of all-optical fiber interferometric sensor based on a U-shape microcavity
Reflectivity spectrum of beam propagation method (BPM), for the first time to the best of our knowledge, is realized and utilized to model all-optical fiber interferometric sensor formed by a U-shape microcavity embedded in a single mode optical fiber and illustrate the principle of sensor structures varied by the length and the depth of U-shape microcavity. BPM analysis gives a constructive guideline to get a high interferometric fringe visibility which is most important for sensing application. The simulated results are completely in agreement with the interferometric sensor principle of Fabry-Perot interferometer (FPI) theory. With the conclusion of FPI sensor, refractive index (RI) sensitivity and temperature sensitivity are then simulated and obtained as 1049±5.2nm/RIU (refractive index unit) within RI range of solutions and 1.04±0.03pm/°C respectively.
The compression of ASE pulses using optical breakdown clipping in liquid
Pengyuan Du, Zhiwei Lu, Dianyang Lin
Using the method of optical breakdown clipping on Krypton Fluoride excimer laser, ASE (Amplified Spontaneous Emission) pulse compression technology was studied in this paper. And the liquid medium breakdown depth on the ASE pulse compression effect was analyzed. The initial ASE pulse width was16.8ns, the shortest 8.4ns ASE pulse was obtained in the experimental. The auxiliary beam induced luminescence breakdown was used to study on the law of optical breakdown clipping, and the short 7.3ns ASE pulse was got. These experimental results proved that the auxiliary beams are useful to accelerating the plasma generation rate and duration. The results ASE pulse compression can be controlled in some degree.
The collapse of fields and density disturbance in laser-produced critical density plasma
The evolutions of density disturbance and fields near plasma critical surface in laser-irradiated solid target are investigated in basis of nonlinear dynamics model. It is found that the collapse of fields is faster in non-static limit case than that in static limit case due to its collapse enters supersonic stage. The intense electric field forming from its collapse drives electron density disturbance that generates electron cavity, simultaneously intense low frequency magnetic field is induced in cavity. The results are useful for studying plasma cavity in fast ignition in ICF and ion acceleration.
Solid state laser ablation effect on laser-proof composite coating applied in aerospace material
Jing Li, Yi Zheng, Jing Luo, et al.
This paper concentrates on the measurement and analysis of laser ablation effect of particularly prepared aerospace material, polycarbosilane (PCS). Laser ablation experiment setup is designed and built, based on a continuous-wave high-power solid-state laser (CWHPSSL). Steel samples with composite PCS coating are prepared. After that, a group of laser ablation experiment is performed. The samples are shot by laser beam with thousands W/cm2 fluence. The results, including the ablation morphology and temperature data, is shown and discussed. Temperature data gives a good demonstration of thermal protection effect of composite coating, and in the meanwhile the morphological features in the ablated region reveal the principle of PCS laser-proof effect. Theoretical investigation has also been carried out. The temperature field is simulated based on Fourier equation of heat conduction, and the simulation result provides a good demonstration on thermal-proof effect of PCS coating layer during laser ablation process.
A novel method for detecting melamine in pure milk
Lu Wang, Bao-jin Peng, Xiaogang Jiang, et al.
The fluorescence spectra of melamine-contained milk solution excited by the exciting light have been experimentally studied in this paper. The experiments show that the melamine-contained milk solution can produce strong fluorescence when excited by 467nm exciting light. The fluorescence spectrum peak is around 540nm and the fluorescence intensity would increase firstly and then decrease with the increasing concentration of melamine in pure milk. Based on this result, combining with the optical technology and computer technology, a simple detection system device has been designed. The device can quickly detect whether the milk containing melamine in real-time and accurately show the concentration of melamine in a certain range, which make the device have strong practicability.
Backscattered signal modulation and emitting module design for a cloud lidar
Xiaowen Shu, Zhenyi Chen, Xu Lian, et al.
The cloud lidar, with the character of high precision and good stability, is an effective way to detect the cloud height. Pulse diode laser (PLD), as an essential part of the lidar system, needs the triggering pulse. In this paper, the emitting part of the lidar is studied,including the simulation of the backscatter SNR, the choose of the PLD and the design of trigging circuit to drive the 905nm PLD with the consideration of the optical system. A circuit for trigging the laser pulse with adjustable power and pulse width is contrived. Then the software Systemview is used to emulate the design and finally the making of PCB is finished. The results show whatever the parameters of the pulse, namely trigging pulse width, the rising edge, dithering , all these can be qualified to be in use in the practice and enjoys the merits of the low cost and convenience. The emitting module operates well.