The deformable aspheric polishing lap based on Piezoelectric(PZT) actuator can change the lap surface continuously to fit the surface of middle aperture aspheric optical mirrors at any location. In this paper,a 100 mm diameter and deformable aspheric polishing lap consisting of 19 PZT actuators was designed and manufactured to polish a Φ350 mm hyperboloid mirror in k＝－1.112 155, R=840 mm. In order to analyze the influence of PZT actuator hysteresis on surface error, the output characteristic of each PZT actuator was measured and the mathematical model of displacement output of each PZT actuator was established by means of Radial Basis Function(RBF) neural network. By finite element method, the surface errors of the deformable aspheric polishing lap were calculated before and after PZT actuator hysteresis compensation. The results show that the surface residual error and RMS are 1.910 μm and 0.342 μm respectively. By PZT actuator hysteresis compensation, the surface error of the deformable aspheric polishing lap reduces by 82%.

High-power laser diodes based on GaAs semiconductor bars are well established as reliable and highly efficient laser sources. As increasing applications of semiconductor lasers in the laser processing, the single laser diode optical power has not satisfied for the actual requirements. In this paper,the improving laser output methods to couple several diode laser beams into one beam or to couple laser beams by an optical fiber to output directly to improve the brightness were researched and the principle and key technique for wavelength coupling in inherent coupling were introduced. The wavelength coupling technology was used to couple two laser beams with wavelength of 808 nm and 980 nm together, the beam splitter cube and optical focusing lens were designed for the experiment.Experimental results show that the overall efficiency is about 70% and spot size about 3 mm×3 mm,which can satisfy the system application requirements for metal cladding and welding directly.

An infrared CO2 gas sensor was developed based on space-double-beam structure. First,the structure and working principle of the optical probe were introduced.A new-type gas cell was presented and the optimal size of the gas cell were calculated in detail. Then, the linear mathematical model of the sensor was established based on Lambert-Beer Law, the principle of space-double-beam optical structure and the working model of an infrared light source in turning on and off periodically. Finally, the unknown coefficients in the mathematical model were calculated with Least Squares Method. The characteristics of the infrared sensor were tested in static state, tested results show that the values obtained from the experiment is close to the true values and the accuracy of the sensor is 0.024 2% when measurement range is 0~3%. The system can work continuously more than 30 days without the disturbance from the temperature signal and background optical signal, it also can work at 5~40 ℃ and on different background conditions. These results conclude that the sensor can satisfy the system requirements of lower-power-consume, higher-precision and stability.

To study the effect of spectral curvature on the acquired radiant signal by imaging spectrometer with prism dispersion, the errors of acquired signal between with spectral offset 0.01, 0.05, 0.1d (d is pixel dimension) and without spectral curvature was calculated by combining with the dispersive characteristics of composite prism in Visible-Near Infrared VNIR (400~1 000 μm). The experimental results indicate that the scene radiant signal acquired by imaging spectrometer with spectral line bend exhibits distinct errors at the edges of atmospherical absorption bands compared with no spectral curvature, and the normalized signal errors increase with the spectral offset. When spectral resolution increases, there are distinct signal errors near some weak atmospherical absorption peaks. These results reported here suggest that spectral curvature should be no more than 0.3 nm for imaging spectrometer with 10 nm resolution.

A Grazing Exit Micro X-ray Fluorescence (GE-MXRF) system involved with a polycapillary X-ray lens was established to analyze nanometer films. A polycapillary X-ray lens with spot size of 41.7 μm was applied to focus original X-ray and a slit of 50 μm was located in front of the detector to improve angle resolusion. In order to improve the working efficiency,a computer program was compiled to realize automatic control. With this system, a series of titanium and ferric layers deposited on GaAs single crystal by Metal Vapor Vacuum Arc(MEVVA) ion sources were measured. The results indicate that this system can analyze film samples effectively,and through grazing exit angle scan and surface two-dimensional scan, the density, thickness and the uniformity of film can be acquired. The spatial resolution of micro-analysis and the real spatial resolution of experiment are 41.7 μm and 50 μm,respectively. The conclusion is that this grazing GE-XRF system can realize the analysis of film sample automatically and quickly, also can acquire the overall information of sample and process these data effectivelly.

A Laminar grating with a 1 000 lp/mm rectangular Laminar groove profile, 13 nm groove depth and a 0.43 duty cycle is fabricated by holographic ion beam etching. The grating is coated by Au in thickness of 40 nm. When the work wavelength is 13.9 nm, the product of the zero order and the first order light diffractions is close to 8.1% at an incident angle of 81.2°, and the diffraction efficiencies of the zero order and the first order are approximately equal. Experimental results illustrate the potential of Laminar grating as a beam splitter at 13.9 nm and also show its efficiency can be higher than 7%.

The Separation of Interference Fringes of the Main Diffraction Maxima (SIFMDM) and the second maximum for Cross Segmented Wedge Array (CSWA) focus system were derived, and the change rules of the Small-scale Irradiation Non-uniformity(SSINU) were confirmed by numerical calculations based on the generalized Huygens-Fresnel diffraction integral theory. The two methods of reducing the SSINU, the Deviation of Wedge Angles (DWA) and the Off-focal Laser Radiation on the Target (OFLRT),were proposed.Theoretical study and experimental results show they agree quite well. By both the DWA and the OFLRT, the SIFMDM can be reduced by 6 times and the SSINU is also improved obviously,when the DWAS and off-focal variables are optimized to δpj=20%,ΔZ=2 mm.

In order to realize 3D shape acquisition for large free surface, a data registration method using optical location tracking technology was proposed. A planar target was fixed on the measurement system as the intermediate, the coordinates of some feature points provided by the target in the measurement coordinate system were obtained by a intermediary coordinate transformation method. A location tracking system was constituted by binocular stereo vision, then,the tracking coordinate frame was used as the global coordinate frame to obtain 3D global coordinate of feature points on planar target to derive the transformation matrix from the measurement coordinate frame to the global coordinate frame. All the 3D data of sub-areas obtained by the measurement sensor were unified in the global coordinate frame, and the global measurement for a large object was accomplished. The registration experiment was conducted using 100 feature points on the planar target, and the results show that the single measurement precision is 0.11 mm, and the RMS error of 3D data registration is less than 0.34 mm. The presented method is simple and flexible, and can satisfy the precision requirements.

In order to minimize volume, lighten the weight of a spaceflight camera effectively and satisfy the requirement of cold copy , the design for spaceborne absolute photoelectric encoder of dual numerical system is put forward in this paper. Based on the requirements of the spaceflight camera, the miniaturization design is applied to absolute optical code disc; Then, a dual numerical reading slit disc and a numerical reading system are developed according to the characteristic of code disc; finally, the precision test is implemented on the spaceborne absolute photoelectric encoder with dual numerical reading system. The experimental result shows that the photoelectric encoder in outline dimension of 50 mm×32 mm, weight of 150 g can offer its resolution of 20″and precision lower than 30″. The encoder has the function of cold copy for numerical reading system, and shows its advantages of small volume, light weight and high resistance,which can meet the requirements of spaceflight camera.

In order to improve the dynamic performance of the correlation tracker in a Space Solar Telescope, and to verify the feasibility and reliability of a beryllium mirror working in visible band,the tip-tilt mirror of the correlation tracker in the space solar telescope was studied. A Φ84 mm lightweight beryllium mirror was designed and fabricated. Beryllium powder was obtained by impact attrition technique, and the beryllium mirror blank was fabricated by hot isostatic pressing technique and mechanical processing. The nickel-phosphorus alloy layer was plated onto the substrate of beryllium mirror by electroless nickel plating, and the beryllium mirror was completed by optical processing. Surface testing results indicate that the surface figure errors of beryllium mirror are PV value of 0.114 λ and RMS of 0.012 λ (λ=632.8 nm), and the lightweight ratio is 43.68%. The results of surface figure error satisfy the technical requirements for the space solar telescope, which shows that beryllium can be used as mirror substrate materials of space astronomical instruments.

In order to improve the fabrication results of polishing off-axis aspheric in Computer Controlled Optical Surfacing(CCOS), a novel algorithm named adaptive programming model to generate a polishing tool-path is discussed based on the balance principle of particle system and the thought of averaging power. Considering the factors influencing the polishing results, the power values are composed of three elements including the constants, error distribution and the dwell distance of work-piece edge. The influence coefficients between the power elements are estimated and simply computed. And then, a groups of error data are simulated with actual parameters using the matrix-based algorithm by two different tool-paths. The first one is X-Y uniform spacing model in common use, and the other is adaptive programming model. The contrasted results show that most of error results of the adaptive programming model are much better than that of the common one, especially the rms convergence rate is improved from 0.36 to 0.62. In the end, several questions on the algorithm are discussed and explained briefly,result show that the theory of the algorithm is simple and exercisable, and can satisfy the practical requirement as well.

A transmission grating with an area of 1 mm × 1 mm, a pitch of 300 nm, and a gold thickness of 1 μm for X-ray imaging and microscopy is successfully fabricated by combining electron beam lithography, X-ray lithography, and electroplating. Firstly, a high-density mask in pitch of 300 nm and gold thicknes of 250 nm for transmission grating is originally patterned on the Si3N4 membranes by electron beam lithography and electroplating. Then, the X-ray lithography and electroplating are used to replicate the transmission grating with the profile thickness of 1 μm, aspect ratio of 7, and the duty cycle about 1∶1.Experimental results show that the fabrication method combining electron beam lithography,X-ray lithography and electroplating has advantages over other fabrication methods in big pitch,nanometer scale and straight side well for transmission grating.

A frequency response measurement method was proposed based on the digitization characteristics of O-E tracking servo system. The testing signal, data acquisition mode, the extraction of amplitude and phase,and hierarchical identification were investigated. The swept-sine signals were generated in the digital motion controller, and the response waveform was sampled and stored on disk automatically. After testing, the stored data were transferred to PC and preprocessed with Matlab software. The phase difference and amplitude ratio were estimated via correlation analysis. Finally, the measurement frequency-domain data were transferred into accurate transfer function with the hierarchical identification method. The experimental results show that the frequency band of the exciting signal is enough for measuring spectra of control systems, and the magnitude phase measurement accuracies of transfer function are ±0.5 dB and ±1° in middle frequency range,respectively, also the parameters of mechanical resonant frequencies can be identified with a bi-quadratic filter in high frequency range. These results confirm that the proposed method is effective and practical.

In order to explore the feasibility of the large lightweight SiC primary mirror, the different lightweight forms were compared and a supporting way for the primary mirror was determined. After theoretically calculating the light weighted structure parameters, a sandwich structure SiC primary mirror with sector holes was designed. With the finite element method, the self-weight deformation for the lightweight mirror upholded by a float support was analyzed. Under the two different conditions, the mirror surface figures were PV=9.43 nm,RMS=2.5 nm and PV=16.7 nm,RMS=3.2 nm, respectively. The results indicated that the influence of the self-weight deformation is smaller while the thermal deformation is larger because of the large coefficient of thermal expansion of SiC. At steady-state temperature field, when temperature changes 1 ℃, the mirror surface figure changes PV=40 nm,RMS=4.8 nm. These results reported here suggest that the thermal control must be applied to the mirror.

To meet the needs of detection of space faint objects for a telescope with large aperture and short focal,a binding drawtube telescope scheme to detect space object is presented to overcome the shortcomings that focal length grows and field of view shrinks with the increasing of aperture size in traditional telescope for space detection.The software methods are used to stack collected images to restrain background random noises and to improve image Signal to Noise Ratio(SNR) and the detecting ability of the whole system. In order to validate the above assumption,four stages of 110 mm telescopes is binded to establish a experimental platform.Through practical observation and post process, the assumption is validated and the analysis result is presented. Experimental results indicate that the image SNR is increased by 1.58 times and the detecting ability is increased by 0.5 magnitude as compared with those of traditional telescope. It is validated that the detecting ability can be improved when relevant focus length is maintained from reducing.

To realize the active control of each segment of a segmented telescope, the figure control equation of hexagonal mirrors was built up, and the impact of sensor location on figure control system was studied. A working manner of the active control system based on the measurement requirements of relative segment locations was confirmed. Then, a figure control system consisting of 3 segments was built up, and the influence of the sensor location on figure control was analyzed.And also, a sensor setting scheme in which sensor is perpendicularly away in centimeters was put forward. Finally, the applicability of this scheme to the extent of segmented mirrors was testified. The analysis results indicate that the change of location between the mirrors can be exactly measured in fixed two sensors with 0.02 m stagger along the same gap when the segment mirror has side length of 0.9 m and diagonal length of 1.8 m,also the control system can give out the correct adjusted information of actuators. These conclutions reported here show that proposed scheme can satisfy the requirements of real time and high precise control of the active figure of the segmented mirror.

By comparing of the research and development of optical system in a large telescope at home and abroad,a scheme for establishing error budge system was presented to determine the influential factors on optical system to ensure the expected precision in design,manufacturing and assembling of large aperture optical system. By taking a 1.2 m telescope optical system as an example, the conformation of error budget was introduced and a reasonable static error allocation was worked out. Firstly,a total error standard was determined, then, the number of error budgets was counted,finally,error budge result was given based practical ability of manufacture and assemblage.Experimental results show that the RMS wavefront error of this telescope optical system is less than λ/8.5, which matches the machining and assembling capacity.

The mechanical mode of an Half coated Metal core Piezoelectric Fiber (HMPF) actuator is established. According to the constitutive piezoelectric equations, the analytical expressions of the tip deflection, blocking force and the natural frequencies are derived. The effect of the metal core on those properties of HMPF actuator is investigated based on the numerical results of the equations and FEM. The experimental results indicate that the maximum tip deflection of cantilevered HMPF, maximum blocking force and the first resonance frequency are 589 μm,427 μN and 28 Hz,respectively, FEM results are coincident with theoretical values on the whole. The results show that the actuator can give a big deflection, a small block force, and a low resonance frequency.

On the basis of a new type of functionally gradient (FG) piezoelectric actuator proposed by the authors in their former study,the new actuator is designed, fabricated, modeled and experimentally studied. The material compositions are selected from Pb(Ni1/3Nb2/3)O3-PbZrO3-PbTiO3 family and they are used as the four layers in the new FG piezoelectric actuator.The piezoelectric constants and dielectric constants of the materials are gradated oppositely in the thickness direction, because this special structure of the FG piezoelectric actuator has an advantage over the traditional actuators in internal stress distribution. To optimize the structure of the FG piezoelectric actuator, an electromechanic model is derived from Classical Lamination Theory (CLT) and piezoelectric equation, and the static distortion and stress distribution of the actuator with different thickness ratios are computed when the voltage or concentrated force effects on it independently.The optimum thickness ratio is 1∶1∶1∶1, which is determined by optimizing the internal stress distribution.According to the optimizing result,the FG piezoelectric actuator is fabricated successfully,also the relation between the output displacement and output force at the free end of the actuator is measured. The experimental results indicate that there is a linear relation between the output displacement and output force of the actuator, moreover, the lower vibration frequency is, the greater output displacement and output force are.

Application of active vibration control system based on piezoelectric elements in real-world structures is limited by its requirement for complicated signal processing system and bulky energy supply system;the passive vibration control system is also difficult to implement its system paramenters of inductance.Moreover,the resistances in this system are sensitive to environment,so that it needs large inductance to control low frequency vibration. In order to overcome these drawbacks, a new method of semi-active vibration control based on a technique of synchronized switch damping has been developed recently. By using the processor of TMS320F2812 and the logic switch control algorithm,the polarity of the voltage on a piezoelectric element embedded in cantilever composite beam can overturn at proper time, so that the vibration controlling effect is achieved due to the opposite directions of the voltage-induced force and the strain rate. The experimental results show that the first mode of the cantilever beam can reduce by 3.164 1 dB.

To fabricate high-performance lead-free piezoelectric ceramics, both the solid-state reaction method and the hydrothermal method were used to synthesize the (KxNa1-x)NbO3 (KNN) lead-free ceramic powders in this work. The ceramic powders were shaped using press forming method at different pressures and the sintering properties of ceramics fabricated from different powders were investigated. Then,the relationship between the account of PVA and the density of ceramics was discussed. The piezoelectric constants of the KNN ceramics polarized at the different voltages, and the dielectric constants against temperatures were also measured. The results show that the powder prepared by hydrothermal method has better sinterability compared to that prepared by solid-state reaction method. Moreover,the addition of K content lowers the sinterability of ceramics. The density of ceramics is very sensitive to the sintering temperature. The K0.5Na0.5NbO3 ceramics fabricated at 1050 ℃ for 2 h has higher d33 (90 pC/N), and its Curie temperature is 410 ℃.

To ensure safety for a handling robot used in polymer microfluidic chip, a reliability design was presented by researching the collision protection between handling robot and objects around. A collision protection system mainly based on a relay and a electromagnetic brake was designed to distinguish collision signal and to complete protection for handling robot immediately. The position precision of the handling robot caused by the collision protection system was calculated and analyzed. The experimental results indicate that the inertial displacement can be controlled to less than 1 mm and the collision protection system has no affect on position precision. These results means that designed system is beneficial to reliability and automation of the microfluidic chip automated fabrication system.

A novel linear hydraulic motor driven by piezostack pump (piezohydraulic motor) was presented, and its structure and working principle were introduced. With establishing the static-state model, the influence factors of the piezohydraulic motor were picked up and analyzed. The theoretic results show that the output capability of the piezohydraulic motor depends on the structure and size of the piezostack/pump-chamber/check-valve/cylinder, the driving frequency and even the external load. The desired performance of piezohydraulic motor will not be achieved unless the relative parameters are matched well. Moreover,when an applied load is equal to half of the blocking force, the maximal output power can be obtained. A piezostack pump with 30 mm chamber-diameter was fabricated using a piezostack in 4 mm×4 mm×80 mm,and the experiments on the unattached pump and the overall piezohydraulic motor were carried out for comparison on their flowrates, pressures and output powers. Analyzed results show that the maximal thrust, velocity and the power of the piezohydraulic motor are 32 N, 12.5 mm/s and 93 mW, respectively,when a cylinder with chamber diameter of 15 mm are utilized.

In order to eliminate the vibration of Magnetically Suspended Flywheel(MSFW), the disturbing sources of MSFW are analyzed.Aimed at the suppression of main disturbing sources, the unbalance vibration, a new active vibration system based on TMS320C6713B+FPGA digital controller is presented. The active vibration control method, hardware constitution and functions of digital controller are discussed. The implement of control method in DSP, the organization of multi tasks in FPGA and the control of peripheral devices are provided. The experimental results demonstrate that the unbalance vibration has been reduced to 3.2％ by proposed system, which shows this system can eliminate the unbalance vibration of MSFW significantly and has great significance and value for increasing the stability of attitude control and for improving the resolution of earth observation.

A mechanical grating tiling device is designed by a macro-micro dual-drive parallel mechanism with a few Degrees of Freedom(DOF). The raster matching device is composed of a macro-moving part using a step-motor controlled ballscrew unit(a 5PTS-1PPS parallel mechanism)and a micro-moving part using a piezoelectric ceramics controlled flexure hinge(a 5TSP-1PPS parallel mechanism) in series. The DOFs for the macro-moving part and the micro-moving part have been calculated and the control algorithms are deduced through inversing dynamics of parallel mechanism. Then, the point-point controls of the macro-moving part and the micro-moving part are simulated subsequently. In order to improve positioning precision of this mechanism, system errors have been analyzed and modified. Finally, above control algorithms are applied to the grating tiling device and experimental results indicate that the maximum linear location error is 3.6 μm and the maximum rotation error is 4.4 μrad for the macro-moving part; the 0.06 μm and 1.2 μrad for the micro-moving part,obtained data can meet the precision requirement of grating tiling system.

In order to achieve smooth wet etching surface of silicon, ultrasonic technology is introduced in the wet etching of silicon. By improving the ultrasonic wet etching system, the temperature difference between top and bottom etching solutions can reach 0.5℃. Then, at 60℃(100), silicon is etched wetlly by KOH solution in mass ratio of 10%, ultrasonic frequency of 59 kHz and ultrasonic power ranging from 60 W to 180 W (every 10 W). Finally, the post-etched surface roughness is measured by Laser Scanning Confocal Microscope (LSCM), and the effect of ultrasonic parameters on the quality of etching surface is discussed. Experimental results indicate that the smooth etching surface can be obtained in roughness Rq of 0.02 μm at ultrasonic power of 120 W. The quality of etching surface is greatly improved in the ultrasonic wet etching system, also the etching surface of high quality can be obtained with suitable ultrasonic parameters in lower temperature and concentration of KOH solution.

In order to get geodetic coordinate and guide an aircraft to capture target,a measuring orientation method is proposed to obtain the location coordinates of aircraft and known target by GPS technology.Then,a homogeneous coordinate transformation method is used to transform coordinate in orientation guide process to obtain the target data of orientation guide process.The measuring orientation technology based on airbone GPS is validated by the experiment,the result shows that the position accuracy is 30 m,and the guide accuracy is 2°.In order to obtain the accuracy range of error,the experiment error is analyzed by Monte Carlo,and the experimental result is within the expected range of error.The experiment shows that measuring orientation technology based on airbone GPS has a certain promotional and practical values.

In order to improve the accuracy of iris recognition further, an iris recognition method based on the maximal responding orientation of phase congruency is proposed. Firstly,the normalized iris images are obtained by preprocessing eye images. Then, the maximal responding orientation of phase congruency for each pixel is extracted and the numbers of maximal responding orientation is encoded into a simple binary iris code that is easy to be processed. Finally, the difference of two iris codes is measured through weighted Hamming distance and the recognition results are given. The experimental results demonstrate that the proposed method has the equal error rate of 0.871 5% and the correct recognition rate of 99.851 8%. Compared with the classical methods, the proposed method has a higher accuracy.

In accordance with complicated object movement and changeable object environment, a multi-pattern fusion algorithm for target tracking is presented. Mean-shift and particle filter algorithms widely applied to target tracking are selected to get tentative locations and Weighted Composite Reference Function (WCRF) is adopted to establish reference model. Then, the distance difference of the tentative locations and the reference model is considered as a criterion to find correct location. Finally, the algorithm updates the reference model according to the distance between reference model and target model in current frame. The experimental simulation results show that the average tracking error of the proposed algorithm is reduced by 50% as compared with that of single target tracking method. If the reference model is updated incorrectly, the probability to find the correct location in the next frame is 67%. After updating the reference model three times, the influence on object tracking is less than 10%,which effectively reduces the tracking error and instability for model updating.

An autonomous predictive centroiding algorithm of unmatched stars is presented in this paper to obtain the real star centroidings of identified stars with star tracking algorithm. All the unmatched stars within Field of View(FOV) are searched from a guide star catalogue according to identified stars. Then, these ideal centroidings of unmatched stars are calculated through these identified stars. The algorithm can obtain the real centroidings of unmatched stars within some threshold scan windows of star image and can identify the centroidings of unmatched stars through the identified stars within FOV,so that recognition performance is improved. The algorithm is successfully demonstrated by real space experiments, experimental results show that the number of pixels of scanning star image by the proposed algorithm is only 0.12% of that by local obtaining star location algorithm,when unrecognized star locations are captured. The conclusions reported here prove that proposed method can improve the update rate of data.

The working principle of curtain type shutter in an aerial camera is introduced and the relationship between sensitive characteristics and resolution for a film is analyzed. Then, expression of the best exposure is deduced by the parameters of photosensitive material. Finally, expression of the slit width is worked out by calculated expression of the exposure time. According to mapping EK3412, the best exposure is 0.073,0.098,0.116 and 0.136 lx·s ,when the image speed is 10,15,20 and 25 frames/s. After flying experimental verification, the resolution of the film can be increased by 10%~20%,which is closed to the theoretical resolution of 130 lpm. By controlling exposure amount to the mid-point on straight line of the characteristic curve, the resolution of photo be can significantly improved to meet the requirements of image interpretation.

In order to obtain steady image sequence from unsteady camera and to realize object tracking based on image stabilization,a separating method of active scanning movement from random jitter of camera are presented. Mean Shift with Particle Filter (MSPF) algorithm is proposed to realize motion separation. This algorithm uses particle filter to forecast particles, and then move them to be close to the real position of object through single mean shift iteration,which can undermine the dependence of the calculation accuracy on the number of particles. To a complex background in reality,the MSPF algorithm can be used to separate active scanning movement from random jitter of camera, and then image difference and motion compensation can be used to detect moving object to realize the stability of image tracking. Experimental results show that the MSPF algorithm with 50% particles can achieve the same effect with traditional particle filter,which means proposed algorithm can shortens process time and can realize real-time image stabilization for vehicle-borne, ship-borne, air-borne and other stable tracking systems.

To realize color image segmentation, target identification, feature extraction, and other image processing projects, the image preprocessing methods are researched. Based on analysing characteristic of digital camera and human visual error and understanding data formats of color image,an octree arithmetic is applied to color quantization and a vector median filter is used to eliminate noise to realize preprocessing for color images. In combination with a experiment,this paper discusses and analyzes window parameters of vector median filter,and presents an effective evaluation methods by combining color information similarity theory. Finally,a reasonable color quantization method and window parameters are obtained for digital camera, and the chromatism can be controlled within 3 units. Experimental results show that octree color quantization and vector median filter can perform well in preprocessing of color image for digital camera.

In order to eliminate the interference of airborne environment and to improve the precision of decode and the EMC ability, the filtering of IRIG-B (AC) and the compensation of phase hysteresis caused by the filter are studied. A band-pass filter with a 1 kHz center frequency is designed, then the digital compensation is used for the phase hysteresis caused by filter. The results show that the ability of anti-jamming, anti-distortion and the decoding stability of the decoder are improved,and the useless frequency signals are depressed by -34 dB/10 octave. The digital compensation strategy can eliminate not only the phase hysteresis, but also the error caused by zero-crossing detector. The timing precision of 1 PPS is enhanced from better than 10 μs to better than 3 μs.The airborne system satisfies the decoding requirement of IRIG-B (AC), eliminates the noise interference and signal distortion,and enhances the decoding precision and stability.

To establish a more effective string pattern matching algorithm, a new improved star identification algorithm taking angular distances between main star and neighbor stars as recognition characteristics is designed. A guide star catalogue is constructed,and the angular distance values between main star and neighbor stars are encoded to quantized codes; then each code in characteristic character strings is rearranged from small to large in sequence. A string length code is appended to the end of the string to improve search speed of guide star catalogue, and so far the main star’s neighbor pattern is finished. Finally, an improved string matching algorithm based on KMP is proposed to identify the corresponding matches to the measured star in the whole guide star patterns. The identification rate of this algorithm is greater than 97.38% when the Gauss noise of position error is 2 pixels. 1 250 star maps are identified randomly on Pentium 1.6 GHz PC,and the average identification time is 42.78 ms. This algorithm has rotation invariability, good robustness and synchronization. The catalogue storage content is only 149.4 kB,so it can offer a higher retrieval efficiency.

In order to improve the speed of restoration algorithm, a parallel Wiener filtering method based on Graphic Processing Unit(GPU)platform is presented to restore motion-blurred aerial image degraded in a deterministic way by motion or vibration. The shortages of the original algorithm using Wiener filtering and original PC run-time platform are introduced. On the basis of the new General Purpose GPU (GPGPU) technology, the original algorithm is divided into thousands of single algorithm threads to be computed in parallel. According to the special simultaneous operating mode of GPU hardware, a way in which the algorithm threads access the data on the GPU global memory is specially configured to improve the accessing speed, the algorithm efficiency by the special configuration can even be improved roughly 3 times that by original configuration. With the parallel computing ability of GPU, the new algorithm can restore 1 024×1 024 gray image in 8 ms per frame. The experimental result shows the new algorithm based on GPU reaches approximately 20 times that of original algorithm based on CPU of personal PC, which can completely be applied to the real time restoration of high resolution motion-blurred aerial image.

In order to realize the ultra high-speed image storage in the high accuracy measurement of opto-electronic tracking and measuring system, an image storage scheme based on Double-data Rate Dual In-line Memory Module(DDR DIMM) array technology is put forward. By using the DDR DIMM memory as storage medium and the Field Programming Gate Array(FPGA) as memory controller, a storage system is established. The block diagram of overall design is introduced,then the modules of DDR DIMM array controller and the methods of image data input and output are discussed. The experimental results indicate that the image data storage rate has come to 1 000 MB/s. Actually, analysis show that the scheme can achieve a higher speed to 1 828 MB/s,which can satisfy the requirements of ultra high-speed image data storage of high frame frequency and high resolution image sensors in the high accuracy measurement of opto-electronic tracking and measuring system.