Aimed at active weak IR detection, how to get the stable high gain from Avalanche Photodiode (APD) circuits and its opto-electronic matching characters are researched. The methods are relation with APD exponent gain and linear noise with its reverse bias voltage. It gets closed to temperature coefficient by serial Zener diodes and always-stable bias voltage to APD near break voltage at real PN junction temperature, and is over 100 times gain with temperature complement circuits. Transistor cut-off frequency and its response are increased by NPN type transistor with an improved a.c. couple low noise and low voltage supplier negative feedback circuits. The system voltage gain enhances 2 to 3 times,and opto-electronic sensitivity rises over 23 dB. Because PN junction temperature of power LD changes causes wavelength drift, it is very difficult to match extremely narrow bandwidth interference filters. So the interference filter bandwidth between 10 and 15 nm is available for background radiation depression.Avalanche Photodiode/APD; low noise amplifier circuit; temperature complement circuit; narrow bandwidth interference filter; IR background radiation

In order to realize laser lighting for a small moving target in a region, a design solution of laser light system which consists of rotary mirror and point laser lighter was proposed. The relationship between laser light curtain and rotary mirror parameters which include sides, circumscribed circle diameter and rotate speed was deeply discussed. Using this laser light model, the average laser power density on the target is related to laser power, laser scanning speed, laser beam degree, camera exposure time and distance between target and laser light. The formula which reveals the internal relations above-mentioned was deduced. The results of simulation and experiment show that the above-mentioned solution of laser light system is feasible and the formula is correct. The laser light system can be used to light for vision measurement system and can meet the expected results.

High power diode laser vertical stack’s collimated beam pointing error and the influence of the pointing on the laser beam are introduced. The experimental device is built, and single anastigmatic far field lens are adopted to collect the light spot of the vertical stacking. By combining the centroid arithmetic measured continuous work 2 kW vertical stacking diode laser, the results of collimation beam's pointing accuracy was ±1.7 mrad. The errors of the metrical method are analyzed and some routes are optimized to improve the metrical method.

When the current anti-radiation technology and anti-radiation missile technology developed rapidly, active antiaircraft warning system can be easily found and attacked. Passive warning system is designed based on real-time scan-image processing by the optical imaging method to achieve region-wide early warning. A new parallel image processing structure is proposed to achieve real-time recognition of early warning air targets. At the same time, a new iterative identification algorithm is proposed based on Rough Sets (RS) and Support Vector Machine (SVM). The training data sets are separated into some blocks and their samples in sort-subjection are arranged to speed up the selection for support vector and the construction of the optimal interface. Therefore, training time of the sample set was greatly reduced and the recognition rate, generalization, realization performance of its recognition function was increased. Experimental results show that the system reached real-time early warning of air requirements while target recognition reaction time was about 15.1 ms and recognition rate was as high as 93%.

A dim-small target detection algorithm based on the classification of the background is presented to reduce the influence of the complexity of the background. The classification of the background is based on the complexity of the background. The complexity of background is estimated by the entropy of the image. And the lower-resolution wavelet transform idea is introduced in order to simplify the algorithm. Then the entropy of the image is mapped to the fuzzy plane as a background factor image by the fuzzy membership function. The complex background is separated from the flat sky background to realize the background classification through thresholding the background factor image with the maximum entropy threshold segmentation. Next the target is separately segmented by using the Robinson filtered image based on the two type of background characteristics to reduce the influence of the complexity of the background. The experiments show that this algorithm can reduce the interference of complexity of background for small objects, and it can improve the probability of the point target detection.

Heavy load has two main impacts on the shipborne optical-electric platform. The first one is the decrease of the resonance frequency, narrowing the bandwith of the system, and the second one is the increase of the disturbance. To ensure the precision of stabilization, it needs to improve the torque rigidity of the system and compensate the disturbance. A method is proposed which adds the current loop into the closed speed loop formed by the tachometer, and uses the gyro to get the feedforward compensation of the angular speed, and uses an observer to restrain the disturbance. The theory and simulation results demonstrate that the current loop can enlarge the torque rigidity of the system, the gyro feedforward can improve the isolation of the ship-sway, and the disturbance observer can greatly compensate the disturbance. The method enhances one magnitude for the stability, and provides an instruction for the engineering practice.

In order to estimate longitude and latitude shafts rigidity and resolve conflict between shaft error test result and actual work performance of the 40 cm alt-alt telescope, vibration modes and gravity deformations at the different angles of the shaft were analyzed respectively by Finite Element Method (FEM). Frequencies and the max deformations of longitude and latitude shafts indicated that shaft rigidity satisfied the design requirement. From 0° to 180° longitude angle, longitude shaft shake error caused by gravity deformation was calculated. The shake error caused by structure deformation has the same sinusoidal variation pattern with the shaft error test result. The longitude shaft precision amendment is obtained by the compensation method that subtracting the calculated results from the test result. The shaft precision PV value is improved from 7.2″ to 2.6″ and the RMS value is improved from 0.7″ to 0.3″. The corrected shaft shake error is consistent with actual work performance state, and represents actual performance of the alt-alt telescope longitude shaft.

The ground-based telescope is traditionally tested by autocollimation against a flat mirror. As the aperture of telescope goes larger, the testing can not be performed any more because of the more severe limitation of unstable environment and impracticably flat mirror. The solution of testing wave-front by sub-aperture stitching technique based on Shack-Hartmann wave-front sensor is introduced. This paper begins with a simple description of Sub-Aperture Test (SAT) theory, and explores the methods aiming at more accurate Shack-Hartmann sub-aperture test result. A new trick, that put a plane with holes in the parallel light path, can make sure the location of sub-aperture hit the target. A 32 units Shack-Hartmann wave-front sensor and a 40mm flat mirror is used for testing a optical system 1.8 times larger than the flat mirror and the sub-aperture test results are stitched by two different ways. The experimental results show that error averaging method is superior in error propagation property to stitching one-by-one method, and Peak-to-Valley of the difference between the direct measurement and SAT result is 0.5 wavelength. It is concluded that the technique is useful and has a good application future in practically testing the wave-front error of great telescopes.

A metallic grating structure which can enhance Second-harmonic Generation (SHG) based on exciting Surface Plasmons (SP) is studied. By designing the structure parameters of the metallic grating with quasi phase matching condition, the SP of the fundamental mode and the second-harmonic mode can be excited simultaneously, which considerably enhance the efficiency of SHG emission. Numerical simulation for SHG behaviors of designed structures were performed by using the Finite Difference-time Domain Method (FDTD) and the results showed that the quasi-phase-match condition and the excited SP mode made a key role for enhancing the efficiency of SHG. Moreover, the effect of the structure parameters of the metallic grating on SHG emission was analyzed.

A Fiber Bragg Grating (FBG) is increased in the optical cables, which can be used for monitoring the cable real-time temperature. Finite-element method is used to establish the temperature field model of optical cables. The tunable laser was used as source, and some fiber Bragg gratings with same center wavelength were used as system temperature sensor. In optical cable lines when the temperature is abnormal, the reflected grating center wavelength will shift. By detecting the center wavelength offset of the reflected light, the size of the grating temperature change can be determined. Grating at different positions reflected optical signals needs different time. By detecting and calculating the interval time of reflected light, the location and the temperature of the grating whose temperature has changed will be obtained. Experimental results show that grating temperature sensitivity reaches 11.4 pm/℃. The deviation between the measured temperature and the actual temperature is within 3% range.号处理等方面的研究。成像系统研究”(F2010001268）；河北省科学技术研究与发展计划项目“传感光电缆的开发与应用”资助(10213509D)

A new measurement trace gas concentration system of Continuous Wave (CW) Cavity Ring-down Spectroscopy (CRDS) based on the effects of Sagnac and the measurement principle of cavity ring-down is proposed. Thefiber loop based on the Sagnac effects served as a reflector and formed a resonator with a high-reflectivity reflector. It can achieve the reflectivity of the resonator tunable, therefore, the requirement of the intensity of incident light is decreased and condition of the signal processing is provided. On this basis, the theoretical analysis and derivation of fiber loop’s Sagnac effect and the measurement principle of cavity ring-down are proposed. Meanwhile, we can obtain: the relationship between the reflectivity and fiber loop rotational speed, the formula of measurement of the trace gas concentration based on CWCRDS, and the influence of the fiber loop rotational speed on the measurement system of trace gas concentration. Finally, the various performance indexes of the system are proved via the simulation experiments.(20070216004)

In order to realize early design of constant-temperature water jacket of lithography lens, a downscaling model test for constant-temperature water jacket is designed with similarity principle, and the method of this downscaling model test design is proved to be correct by numerical simulation. First, governing equations of heat transfer are given based on structure of the constant-temperature water jacket. Then, the governing equations are analyzed, and the similarity criteria of model test design under steady-state heat transfer are derived. Thirdly, a 1:4 downscaling model of a constant-temperature water jacket of lithography lens is designed with the similarity criteria. Finally, thermal distribution in the 1:4 downscaling model and its prototype are analyzed by numerical simulation, and results show that the thermal distribution between them are similar to each other. It can be concluded that the downscaling model test design for constant-temperature water jacket of lithography lens should meet the criteria as follows: geometric similarity, Reynolds number similarity, Prandtl number similarity, Biot number similarity and boundary conditions similarity.

The design of CORBA distributed network management interfaces for an OADM equipment is introduced. The Equipment Management System (EMS) framework for the equipment, based on SNMP and coded in Java, as well as its Management Information Base (MIB) is described in detail. To make the OADM equipment capable of being managed conformably in a distributed network, the implementation processes of CORBA naming service interface and notification service interface using Open ORB kit are developed. The result shows that, by providing these interfaces, the equipment can be well managed in a network following TMF814. This example is of help to those who want to deploy a kind of equipment in small quantity with low-cost distributed network management interface.

As the laser interference microscope testing technology is only suitable for the measurement of relative altitude in surface topography testing and is not available for absolute measurement, the method by using white light interference microscope testing technology is presented. The measuring instrument based on the white light interference theory is developed, and the calibration between the pixel of CCD and PZT is carried out. The topography of the testing surface is calculated with the micro-displacement of the center of zero class white light fringe, which is located through spatial frequency-domain algorithm. The experiment is carried out, and the result shows that the method is available for measuring the topography of plane surface, bench surface, film surface and sphere surface.

Determining pose parameters for space target based on optical sensors and computer vision theory is full of both practical value and theoretical significance. An efficient point-based pose estimation algorithm is proposed to improve the precision and real-time ability of the pose estimation system. In our method, we first get the initial value for target pose through the classical Perspective-3-Point (P3P) method, then introduce the Orthogonal Iteration (OI) optimization method to make a accurate solutions. This pose estimation approach can be applied in any situation with feature points non-coplanar and the number larger than three. Practical experimental results indicate that when the feature point number is up to eight, the RMS error is less than 3 milliradian (0.17°) and the refresh rate achieves 200 frame/s.

The modulation efficiency is an important character in swinging interfernence spectrometer. From the principle of swinging interference spectroscopy, a theoretical analysis about influence of curve error of mirror, performnce change of beam splitter and tilt error of moving mirror on modulation efficiency is presented. Based on analysis results, some expressions of modulation efficiency are provided. Furthermore, the relationship between modulation efficiency and performance parameters is pointed out.

When the Millimeter-wave (MMW) radiometric imaging is carried out indoors, the radiometric temperature contrast between the target and the background decreases sharply, which leads to degradation of MMW radiometric images and difficulty in recognizing targets. Based on the realistic problem of MMW radiometric imaging for detecting contraband concealed on personnel indoors, the radiometric temperature transfer model was put forward. At the same time, both the apparent temperature distribution and radiometric temperature contrast between target and human body were deduced. Combined with the specific parameters of some typical targets, the reason for low indoor radiometric temperature contrast was analyzed. Then, the method of noise illumination was adopted in the application of indoor radiometric imaging, and the contribution of this method to the improvement of indoor radiometric temperature contrast was emphatically investigated. Moreover, from the perspective of radiation power density, it was proved that noise illumination was safe to human body. Both the theory analysis and simulation results are presented to demonstrate the feasibility and significance of noise illumination.

To meet the high accuracy optical testing requirement, the absolute measurement technologies instead of traditional testing techniques are more and more used in optical testing. However, the traditional absolute measurement technology has its own scope and complexity of the experimental process which required experimental equipment with high precision. In the filed of only rotationally asymmetric surface error required, rotating average method is a simple absolute measurement technology. Rotating average method is applied to rotationally asymmetric surface error testing of plane, spherical and aspheric. The principle of rotation averaging method was introduced. Then optical design software was used to simulate the testing process of rotation averaging method. By simulation test, the shape of the rotation asymmetric error and the kNθ rotation error were analyzed, simulation results in good agreement with theoretical results. Simulation experiment results show that rotating average method can effectively improve the testing precision of rotational asymmetric surface shape and the experimental simulation model can effectively simulate the actual testing process.

The compensation method for the error of diamond tool’s cutting edge is a bottle-neck technology to hinder the high accuracy aspheric surface’s directly formation after single diamond turning. Especially to the big relative aperture aspheric, influence is bigger. Traditional compensation was done according to the measurement result from profile meter, which took long measurement time and caused low processing efficiency. A new compensation method was firstly put forward in the article, in which the correction of the error of diamond tool’s cutting edge was done according to measurement result from digital interferometer. First, detailed theoretical calculation related with compensation method was deduced. Then, the effect after compensation was simulated by computer. Finally, φ50 mm , radius 50 mm, work piece with big relative aperture finished its diamond turning and new correction turning under Nanotech 250. Testing surface achieved high shape accuracy PV=86 nm and RMS=7 nm, which approved of the new compensation method agreeing with predictive analysis, high accuracy and fast speed of error convergence.

YbF3 films were prepared under three different vapor incidence angles with special technics. Micro- surface roughness and transmissivity of the film were measured by Atom Force Microscopy (AFM) and infrared spectrophotometer, respectively. Its refractive index was calculated using envelope method and the stacking density was evaluated according to the calculated refractive index. The experimental results indicate that surface roughtness of the film deteriorates with the increment of the vapor incidence angle, while the refractive index and the stacking density decreases with the increment of the vapor incidence angle.

A new method for detection of Volatile Organic Compounds (VOCs) is studied by using an optical waveguide sensor. The sensitive element was synthesized by Sol-Gel method and characterized with XRD pattern. The sensor was fabricated by coating the In2O3 thin film over a tin-doped glass OWG. The OWG sensor was fixed on the gas sensor system to detect the VOCs gases. The results show that the thin film has high sensitivity towards xylene gas at room temperature .This sensor responds significantly to 1×10-6(volume ratio) of xylene vapor.

In order to solve the problem that image interpolation based on adaptive steering kernel regression results in whole gray deviation and some empty pixels in interpolated images, an improved adaptive kernel function for image interpolation is proposed. The improved kernel function was constructed by merging the function of the geometry distance of pixels in neighborhood into adaptive steering kernel, which is produced according to the principle of self-similarity of image. Experimental results show that the proposed method for irregularly and regularly sampled image has a much better effect than interpolation methods based on classical kernel and adaptive steering kernel.

Global modeling is adopted in existing Constant False Alarm Rate (CFAR) algorithms, and the same distribution model is used which estimates the background clutter to detect the whole area. But practical ground covers complex types, and different ground area has its most suitable backgrounds model. The used model is not fit in some regional, making higher loss of CFAR, bringing down the test performance. So an algorithm is presented which judged the areas according to the different characteristics of background, such as statistical variance and mean ratio. In this way, CFAR detector could select the distribution model on the basis of the regional type automatically and get the best detection results: that is, choosing Gaussian distribution in an uniform region. Weibull distribution is used to eliminate the influence while in a clutter edge, and G0 distribution is used to eliminate the obstacles targets while in a multiple targets interfering region, avoiding mutual shielding effects of adjacent targets.

A super-resolution method based on sparse dictionary is presented. The method efficiently builds sparse association between high-frequency components of HR image patches and LR image feature patches, and defines the association as a prior knowledge to guide super-resolution reconstruction based on sparse dictionary. Compared with overcomplete dictionary, sparse dictionary is more compact and effective to express the prior knowledge. We choose the high-frequency component of the HR image patch as its feature for dictionary training, which builds the sparse association between LR image patches and HR ones with better efficiency and less training examples. Sparse K-SVD algorithm is adopted as optimization method to improve the computation efficiency. Experiments with natural images show that our method outperforms several other learning-based super-resolution algorithms.

Through simulating contrast sensitivity function, multi-channel effects and stereoscopic perception of human visual system, a quality assessment method of stereoscopic images based on human visual system is proposed. In the quality evaluation of left and right images by computing Canberra distance, wavelet transform was used to simulate multi-channel effects and wavelet coefficients of different spatial frequency were weighted according to the contrast sensitivity function. The proposed method calculated similarity of the absolute disparity images of the original and test stereoscopic images to assess the stereoscopic perception. Then regression analysis was used to integrate the two evaluation results into an equation as our quality assessment model of stereoscopic images. Experimental results show that the proposed objective method achieves consistent stereoscopic image quality evaluation results with subjective assessment.

Because of the difference response among the detectors in the pushbroom satellite, striping is an obvious phenomenon in the remote sensing image along the scanning direction. A relative radiometric correction algorithm is put forward based on the adaptive filtering pattern. Firstly, the suitable 1-D nonlinear filter is chosen to remove the obvious striping according to the image striping distribution. Then, the 1-D smoothing filter is used to calculate the gain and offset coefficients. At last, the thin stripping is destriped with the obtained coefficients. The comparison experiment proves that the algorithm can effectively improve the image quality, and remove the stripping along the scanning direction, at the same time it preserves the image detail.

Aimed to improving the performance of iris matching, a new method for the coarse classification of iris images using Histogram statistics features is proposed. First, the iris image is segmented into eight blocks. Then, we calculate the Histogram ratio of these image blocks and take them as the class feature of iris image type. Finally, the iris images are classified into five categories in accordance with the similarity of blocks. The proposed method has been tested and evaluated on 500 iris cases from CASIA iris database. The experiment results shows that the proposed method classifies iris types with an accuracy of 98.2%. Compared with the initial Daugman iris matching method, a modified matching method, the proposed method with Daugman method, has lower equal error rate and decreases 29.4% matching time.海南大学2009 年度科研项目(hd09xm82)