This PDF file contains the front matter associated with SPIE Proceedings Volume 7512, including the Title Page, Copyright information, Table of Contents, Introduction, Symposium Committee, and Conference Committee listing.

Based on fractional Fourier transform, the double folding operation is studied and introduced into image encryption. This method can implement a kind of the encoding with real number. This characteristic is convenient to the storage and transmission of the encrypted image. The corresponding experimental setup is similar to the scheme of double random phase encoding. With computer, some numerical simulations have been achieved. The analysis on the algorithm from the aspects of validity, security and robustness is made. The calculated results have been demonstrated that the algorithm is effective and has good security.

In this paper, we analyze the security of the classical double random phase encoding (DRPE) technique in Fourier domain, as well as its extended schemes in Fresnel and fractional Fourier domains. These schemes are resistant to bruteforce attacks, for their large key spaces. However, due to the linearity property of their encryption transformations, they are vulnerable to other attacks, such as chosen-plaintext attack and known-plaintext attack. We successfully break each of the three encryption schemes with the help of a certain quantity of plaintext-ciphertext pairs. Each attack is validated by computer simulations. The cryptanalysis indicates that, to minimize the risks, it is recommendable to introduce nonlinear operations to optical encryption systems.

The newly emerging hand vein recognition technology has attracted remarkable attention for its uniqueness, noninvasion, friendliness and high reliability. It is unavoidable to produce small location deviation of human hand in the practical application; however, the existing recognition methods are sensitive to the hand shift or rotation. The test sample is matched with a series of registered images after affine transformation including the shift or rotation by most of researches, this affine transform method can remedy the location deviation to some extent, but the limited range for hand shift and rotation brings users much inconvenience and the computational cost also increases greatly. Aiming at this issue, a hand vein recognition algorithm based on local SIFT (Scale Invariant Feature Transform) analysis is developed in this contribution, which has practical significance due to its translation and rotation invariance. First, the hand vein image is preprocessed to remove the background and reduce image noises, and then SIFT features are extracted to describe the gradient information of hand vein. Many one-to-more matching pairs are produced by the common matching method of SIFT features, thus the matching rule is improved by appending a constrained condition to ensure the one-to-one matching, which is achieved by selecting feature point with the nearest distance as the optimal match. Finally the match ratio of features between the registered and test images is calculated as the similarity measurement to verify the personal identification. The experiment results show that FRR (False Rejection Rate) is only 0.93% when FAR (False Acceptance Rate) is 0.002%, and EER (Equal Error Rate) is low to 0.12%, which demonstrate the proposed approach is valid and effective for hand vein authentication.

Collision is a situation that occurs when two or more distinct inputs into a security system produce identical outputs, which is undesirable in security applications such as watermarking and authentication. In this report we present a study of the collision property of double random-phase encoding (DRPE) in the fractional Fourier (FRT) domain. For a decade, optical security systems operating in the FRT domain is said to have a larger key space and therefore higher security. However we find that it is still possible to produce meaningful collision from the cyphertext or a watermarking embedded in a host image even without any knowledge about the fractional orders or the random phase keys.

Aircraft fuselage material corrosion problems have been major aviation security issues, which hinder the development of aviation industry. How can we use non-destructive testing methods to detect the internal corrosion defects from the outside of the fuselage, to find the hidden safety problems in advance and update the defective equipment and materials, has great significance for the prevention of accidents. Nowadays, the active infrared thermal imaging technology as a new nondestructive technology has been gradually used on a wide variety of materials, such as composite, metal and so on. This article makes use of this technology on an aircraft cargo door specimen to detect the corrosion defects. Firstly, use High-energy flash pulse to excite the specimen, and use the thermal image processing software to splice the thermal images, so the thermal images of the overall specimen can be showed. Then, heat the defects by ultrasonic excitation, this will cause vibration and friction or thermoelastic effects in the places of defects, so the ultrasonic energy will dissipate into heat and manifested in the uneven temperature of surface. An Infrared camera to capture the changes of temperature of material surface, send data to the computer and records the thermal information of the defects. Finally, extracting data and drawing infrared radiation-time curve of some selected points of interest to analyze the signal changes in heat of defects further more. The results of the experiments show that both of the two ways of heat excitation show a clear position and shape of defects, and the ultrasonic method has more obvious effect of excitation to the defects, and a higher signal to noise ratio than the flash pulse excitation, but flash pulse method do not contact the specimen in the process of excitation, and shows the location and shape of defects in the overall of the specimen has its advantages.

A double images hiding technique based on optics interference is proposed. The images are encoded into two pure phase masks via numerical calculation. Two coherent parallel light beams propagate through the masks and interference at preset positions, the decoded images will appear at preset positions. The position coordinates and wavelength can also be used as encoding parameters. Computer simulation is carried out to verify the algorithm.

In order to maintain the normal running of economy in China, anti-counterfeiting detection of paper currency has been an important technology in the coinage company and the bank, but the detection using spectrum for Chinese paper currency anti-counterfeiting has not been applied in China. A real-time detection method, with broad spectrum including ultraviolet and infrared wavelengths, is proposed in this paper, which achieves the purpose of anti-counterfeiting by using anti-fake properties of paper currency's coating surface, through different lights stimulation the full spectrum light irradiation on currency surface, with its reflection spectrum detected by spectrometer. The proposed method has such advantages as high technology, high detection precision and easy to identify, and has been applied to a practical system, which satisfies the real-time requirement.

The identification technology based on multi-biometric can greatly improve the applicability, reliability and antifalsification. This paper presents a multi-biometric system bases on embedded system, which includes: three capture daughter boards are applied to obtain different biometric: one each for fingerprint, iris and vein of the back of hand; FPGA (Field Programmable Gate Array) is designed as coprocessor, which uses to configure three daughter boards on request and provides data path between DSP (digital signal processor) and daughter boards; DSP is the master processor and its functions include: control the biometric information acquisition, extracts feature as required and responsible for compare the results with the local database or data server through network communication. The advantages of this system were it can acquire three different biometric in real time, extracts complexity feature flexibly in different biometrics' raw data according to different purposes and arithmetic and network interface on the core-board will be the solution of big data scale. Because this embedded system has high stability, reliability, flexibility and fit for different data scale, it can satisfy the demand of multi-biometric recognition.

This paper presents a new approach for embedding authentication information into image on printed materials based on optical projection technique. Our experimental setup consists of two parts, one is a common camera, and the other is a LCD projector, which project a pattern on personnel's body (especially on the face). The pattern, generated by a computer, act as the illumination light source with sinusoidal distribution and it is also the watermark signal. For a color image, the watermark is embedded into the blue channel. While we take pictures (256×256 and 512×512, 567×390 pixels, respectively), an invisible mark is embedded directly into magnitude coefficients of Discrete Fourier transform (DFT) at exposure moment. Both optical and digital correlation is suitable for detection of this type of watermark. The decoded watermark is a set of concentric circles or sectors in the DFT domain (middle frequencies region) which is robust to photographing, printing and scanning. The unlawful people modify or replace the original photograph, and make fake passport (drivers' license and so on). Experiments show, it is difficult to forge certificates in which a watermark was embedded by our projector-camera combination based on analogue watermark method rather than classical digital method.

Automatic seal imprint identification is an important part of modern financial security. Accurate segmentation is the basis of correct identification. In this paper, a DSP (digital signal processor) based identification system was designed, and an adaptive algorithm was proposed to extract binary seal images from financial instruments. As the kernel of the identification system, a DSP chip of TMS320DM642 was used to implement image processing, controlling and coordinating works of each system module. The proposed algorithm consisted of three stages, including extraction of grayscale seal image, denoising and binarization. A grayscale seal image was extracted by color transform from a financial instrument image. Adaptive morphological operations were used to highlight details of the extracted grayscale seal image and smooth the background. After median filter for noise elimination, the filtered seal image was binarized by Otsu's method. The algorithm was developed based on the DSP development environment CCS and real-time operation system DSP/BIOS. To simplify the implementation of the proposed algorithm, the calibration of white balance and the coarse positioning of the seal imprint were implemented by TMS320DM642 controlling image acquisition. IMGLIB of TMS320DM642 was used for the efficiency improvement. The experiment result showed that financial seal imprints, even with intricate and dense strokes can be correctly segmented by the proposed algorithm. Adhesion and incompleteness distortions in the segmentation results were reduced, even when the original seal imprint had a poor quality.

The enhanced transmission spectra and reflection spectra of sub-wavelength fractal structure named Sierpinski fractal structure are presented by means of finite-difference-time-domain (FDTD) simulation. It is found that there are several transmission peaks in the transmission spectra and several reflection peaks in the reflection spectra. The transmission peaks appears red shift and increases with increasing of side length of center square holes when keeping the period of array as a constant. To investigate the physical mechanism of the enhanced transmissions, we simulated the incidence and transmission of THz radiation field at certain transmission peak and show the propagation and distribution of the interior electromagnetic field by the electromagnetic design software named CONCERTO. It is found that different transmission peaks are caused by the different level of square holes. Further analysis reveals that the transmission enhancement is from the interaction of the complicated waveguide coupling effect and the local resonance of electric field. Our simulation is helpful for the understanding of THz wave propagation and THz transmission through the fractal structures of the metal foil.

A chaos secure communication system of mutual coupling lasers ring based on incoherent optical injection is proposed, in which fine tuning of optical frequency is not required compared with other schemes based on coherent optical injection. Therefore the secure communication scheme is attractive for experimental investigation. The dynamics of semiconductor lasers in the coupling ring are examined. Numerical investigations indicate that zero lag synchronization can be achieved under equal coupling time and strength of mutual coupling. Furthermore, by chaos shift keying (CSK), secure communication is simulated with a random bit stream of 1.0Gbit/s. The results confirm the possibility of applying incoherent schemes of mutual coupling lasers ring to realize chaotic secure communication.

Gallic acid is natural polyphenol compound found in many green plants. More and more experiments have demonstrated that the gallic acid has comprehensive applications. In the field of medicine, the gallic acid plays an important role in antianaphylaxis, antineoplastic, antimycotic, anti-inflammatory, antivirotic, antiasthmatic and inhibiting the degradation of insulin. It also has a lot of applications in chemical industry, food industry and light industry. So it is important to study the terahertz time-domain spectroscopy of gallic acid. Terahertz time-domain spectroscopy (THz-TDS) is a new coherent spectral technology based on the femtosecond laser. In this work, the spectral characteristics of gallic acid in the range of 0.4 THz to 2.6 THz have been measured by THz-TDS. We obtained its absorption and refraction spectra at room temperature. The vibration absorption spectrum of the single molecule between 0.4 THz and 2.6 THz is simulated based on the Density Functional Theory (DFT). It is found that the gallic acid has the spectral response to THz wave in this frequency range. The results show the abnormal dispersion at 1.51 THz and 2.05 THz. These results can be used in the qualitative analysis of gallic acid and the medicine and food inspection.

THz emission characteristics of the low-temperature grown GaAs photoconductive antenna under the various types of biased electrical fields are investigated. The biased electric fields including DC (direct current) and AC (sine wave and square wave) are applied on the antenna to reveal the evolution of THz wave. At the condition of effective voltage kept as same and the various frequencies lied between 1 kHz and 9 kHz, we confirmed that the optimized frequency of the biased electrical field is 6 kHz for the sine wave and square wave, respectively. For the case of same effective voltage or biased electric field, the experimental results show that THz signal generated by the sine wave is more efficient than the DC and square wave; this is attributed to the sine wave with higher amplitude of biased electric field. Whereas the experimental results show that the intensity and the signal-to-noise ratio of the THz radiations generated by the square wave are stronger than that of sine wave under the same amplitude of biased electric field, this is caused by the higher effective voltage for the square wave. Therefore, our results indicate that the frequency and type of biased electric fields take an important effect on the intensity and signal-to-noise ratio of the generated THz radiations.

The paper presents a method for the optical storage based on the principle of grating diffraction .The information coding system has included these contents, such as the encoding information, constructing a tow array of grating cells and coding them. The information coding into an array is called the Star-Array Code, because those information as like the flashing stars in the sky sometimes bright or sometimes dark. These information are encoded a group of grating cells with the various space frequency. In the array these grating cells are formed orthogonally each other. There are two methods for designing the encoding, and discuss the foreground of the Star-Array Code is applied.

The angle arc method is proposed firstly to analyse the transmission line angle problem of physics. Linear segment approach is used to deal with boundary integral equation. With this method, nodes on the angle location take on discontinuity boundary condition is solved ,which result in solution is difficult. A general computer program based on angle arc method of the linear boundary element method(LBEM) is programed,and several represented computational examples are given to validate the method. The calculation results are well in agreement with that of the previous published data. It has been shown that this method is provided with a great deal of merits such as simple operation,convenient calculation and can valid to overcome the difficulty in angle problem, so it will have fine general availability.

The paper is mainly concerned with the study of the PBG (Photonic Band Gap) in 2D photonic crystal which consists of a hexagonal lattice of circular dielectric rods with Polyethylene. The result indicates that its PBG is very narrow. According that, a narrow band filter has been obtained by choosing certain parameters of the photonic crystal.

The sensing of the explosive is very important for homeland security and defense. We present a nine-wavelength continuous wave (CW) Terahertz (THz) spectroscopy for identification of explosive compounds (2,4-DNT, RDX and TNT) using three Backward Wave Oscillator (BWO) sources, which emit radiations from 0.2 THz to 0.38THz, 0.18THz to 0.26THz and 0.6THz to 0.7THz, respectively. To identify the target materials, only the transmitted THz power through the explosive pellets are measured at the nine discrete wavelengths. A hole, which is the same size as these pellets, is used as references to normalize the transmitted THz power. The measured discrete spectra was successfully identified and classified by using self-organizing map (SOM). These results prove that the backward wave oscillator is a convenient and powerful solution in future development of a standoff THz sensing and identification unit.

Femtosecond optical pump-terahertz probe studies of carrier dynamics and transport characteristics in semi-insulating GaAs have been investigated under different pump powers at room temperature. The transmission of the terahertz pulse is monitored as a function of delay time between pump and probe pulse, we found that because the more optical generated carriers under the higher power, the terahertz transmission decreased with the increase of the optical pump power. Using a simple thin-film Drude model, carrier relaxation times and carrier mobilities were obtained by fitting the differential transmission curves. The time-dependent and frequency-dependent conductivities also have been studied.

We present a continuous-wave (CW) terahertz (THz) standoff scanning imaging system at 0.2 THz. This system works at reflection geometry and the imaging distance is 30 m. A Gunn oscillator is utilized as emitter and an unbiased Schottky diode operated at room temperature is employed as detector. A polyethylene Fresnel lens is used to collimation terahertz wave for standoff propagation. five aluminum mirrors are employed to increase distance. The sample is placed on an X-Y two-dimensional stage which is controlled by a computer. The collimated THz wave propagates in air and is focused to the sample by another polyethylene Fresnel lens. The back scatted THz wave from the sample surface is collected by the detector alone the same path. The two-dimensional image of sample is obtained by a raster scanning fashion. An aluminum plate with holes, an airplane model and a toy gun contained in a box are imaged at 30 m from the imaging unit. The results show that this standoff imaging system has a wide potential to be applied in the area of security inspection and screening.

Biometric identification is an important guarantee for social security. In recent years, as the development of social and economic, the more accuracy and safety of identification are required. The person identity verification systems that use a single biometric appear inherent limitations in accuracy, user acceptance, universality. Limitations of unimodal biometric systems can be overcome by using multimodal biometric systems, which combines the conclusions made by a number of unrelated biometrics indicators. Aiming at the limitations of unimodal biometric identification, a recognition algorithm for multimodal biometric fusion based on hand vein, iris and fingerprint was proposed. To verify person identity, the hand vein images, iris images and fingerprint images were preprocessed firstly. The region of interest (ROI) of hand vein image was obtained and filtered to reduce image noises. The multiresolution analysis theory was utilized to extract the texture information of hand vein. The iris image was preprocessed through iris localization, eyelid detection, image normalization and image enhancement, and then the feature code of iris was extracted from the detail images obtained using wavelet transform. The texture feature information represented fingerprint pattern was extracted after filtering and image enhancement. The Bayesian theorem was employed to realize the fusion at the matching score level and the fusion recognition result was finally obtained. The experimental results were presented, which showed that the recognition performance of the proposed fusion method was obviously higher than that of single biometric recognition algorithm. It had verified the efficiency of the proposed method for biometrics.

Phase-shifting interferometry (PSI) has proved to be an effective way in recording complex amplitude information with intensity recording devices, especially for the field of optical information security, PSI has shown its great potential. The recent research, development and progress on optical information security by PSI were systematically reviewed and analyzed. Finally the conclusion and further focus in next steps were also demonstrated.