The observation of micro-jet flame shape and measurements of important radicals in micro-jet flame are of great significance to the research and development of micro energy and power system based on combustion characteristics of micro-jet flames. In this work, an optical measurement system of mcro-jet flames was established experimentally to study micro-jet flames using H2 and CH4 as fuels and to measure the spatial distribution of two important radicals, CH and OH. Firstly, the effect of exposure time of camera on images of the H2 micro-jet flames was explored, obtaining the variation of micro-jet flame shape under different flow velocities. Then, the Laser Induced Predissociative Fluorescence (OH-PLIF) technique was applied to obtain the distribution of OH radical in H2 and CH4 micro-jet flames under different fuel flow velocities, meanwhile, a Digital Single Lens Reflector (DSLR) plus a CH filter with a long time exposure (30 s) was employed to obtain the distribution of CH radical in CH4 micro-jet flame. The results showed that, the clarity of flame image is promoted as the exposure time increased and a clear image of H2 micro-jet flame is acquired when exposure time is 30 s; a clear image of distribution of OH radical in micro-scale flames is captured via an ICCD camera with a resolution of 2 048×2 048. The experimental results indicate that the numerical computation of micro-jet flame shape and important radicals is accurate and reliable.

A polarimetric calibration method based on non-polarized light source was proposed to solve the problem of polarimetric calibration of the multi-channel polarimetric imager. Through the study of the interaction between polarized beam and optics, the vector radiative transfer model of multi-channel polarimetric imager was deduced and the calibrated parameters were determined. The key parameters such as absolute radiometric calibration coefficients of center viewing field, polarization degree of optical lenses and relative transmittance with system low frequency were calibrated based on the vector radiative transfer model by application of polarimetric effects of the system with non-polarized light source. By analyzing the calibration result, the Mueller matrix of full field of view was solved. Furthermore, the accuracy of polarimetric calibration on typical field of view was verified with a light source with variable polarization degrees. The results show that the polarimetric calibration method based on non-polarized light source can effectively improve the polarization calibration efficiency of multi-channel polarimetric imager with the measured error of polarization less than 1% and the target degree of polarization less than 20%, thus meeting the requirements of measurement accuracy of atmospheric aerosol.

To realize automatic inspection of welded defects, a dynamic magneto-optical imaging non-destructive detection of weld surface and subsurface defects under alternating magnetic field excitation was researched. The welded defect magneto-optical imaging mechanism based on Faraday magneto optical effect was analyzed and employed to derive the relationship between excitation variation and dynamic magneto-optical imaging by combining with alternating magnetic field principle. The subsurface weld magneto-optical imaging feature test of low-carbon steel was investigated, verifying that the proposed method could be used to detect incomplete penetration defects of weld surface. Finally, dynamic magneto-optical image of high-strength steel weld feature was analyzed and weld defect classification model was constructed through Principal Component Analysis and Support Vector Machine (PCA-SVM) mode recognition method. The result shows that the proposed method can recognize weld features (penetration, crack, sag and perfectness) in high-strength steel weldment with the entire recognition rate of defect classification model reaches to 92.6%, subsequently the automatic inspection of weld surface and subsurface defects can be realized.

In order to measure lubricant film thickness of sliding bearing accurately, a fiber-based spectral-domain optical coherence tomography (SD-OCT) detection system was constructed. The detection system could perform high-resolution imaging to lubricant film with SD-OCT, and the lubricant film thickness was determined according to the relative location of lubricant film and bearing surface in one-dimensional depth image and two-dimensional tomography image. The measuring principle of the SD-OCT was detailed and performed in a film thickness measuring experiment, in which the interference spectrum decouple method was used to reduce the effect of noise on measurement results. Experimental result shows that the system with the measuring error lower than 2 μm exhibits good repeatability and reliability, thus realizing rapid and accurate measurement of lubricant film. The system is expected to be applied in on-line monitoring of bearing operation of mechanical equipment.

To realize the high-accuracy evaluation of adaptive capacity of laser communication terminal to satellite platform disturbance and orbit attitude changes on the ground, the satellite disturbance simulation technique and satellite following analogue simulation technique were researched, from which the ground verification scheme for laser communication system was proposed. Firstly, the effect of laser communication link following detection error on system following performance, as well as the feature of satellite disturbance vibration source was analyzed. Then the model of the vibration source was constructed. The key technology on satellite disturbance simulation and following simulation and countermeasure were analyzed. Finally, combining with current satellite laser communication and satellite platform technology level, the disturbance and following simulation was developed and the laser communication system test was finished via typical data. Experimental result verifies that high-accuracy beam pointing control based on double feedback loop can improve the control accuracy of beam pointing of satellite disturbance simulator greatly, and the beam control accuracy is superior to 0.1″. With the high-frequency and low-frequency joint satellite disturbance simulation method, the high-accuracy beam control of which control bandwidth superior to 1 kHz is realized. Moreover, the detection accuracy of high-accuracy following system to following performance of satellite photo-communication terminal within satellite operating range reaches to 0.1″.

To relieve the ill-posedness of single-view x-ray luminescence computed tomography (XLCT), a fast Bayesian matching pursuit (FBMP) method combined with iterative-shrinking permissible region (ISPR) strategy was put forward.In this method, Bayesian model was combined with the greedy algorithm to quickly and efficiently restore sparse signal from few observed values. To further improve the reconstruction accuracy, FBMP was combined with ISPR strategy to simplify the mesh generation and system matrix construction by self-adaptive finite element, downsizing the factor iterative-shrinking permissible region, meanwhile relieving the ill-posedness of XLCT in reverse solution. In order to verify the effectiveness of the method, a simulation and a real physical phantom experiment were performed. The simulation results show that the proposed method, while speeding up the reconstruction process, significantly improve the localization accuracy of nano luminescent target and quantitative result of luminescence yield, which are 0.73 mm and 0.79 μg respectively. The physical phantom experiment further verifies the feasibility of this method in actual XLCT.

Collection of light field and compression of data in light field imaging technology are urgent problems which need to be solved. In order to realize sparse sampling and restoration of the light field, a camera system to compress samplings based on low-rank structure of the light field was built for researching structural features of matrix of the light field and the reconstruction of light field images under compressive sampling. According to content similarities between each viewpoint image in static light field, those images were vectorized into a two-dimensional matrix by columns. The matrix presented a low-rank or approximated low-rank state. Low-rank decomposition of image matrix in the light field were finished, which shows that deflective low-rank parts emerge strong sparse properties, and low-rank and sparseness separately represented different data redundancies. Then, the camera sampling system fitted with the mask was measured through sparse random Noiselets conversion. Considering the reconstruction process was an optimization solution problem constrained by low-rank sparse correlation, the greedy iterative solution was adopted to separately reconstruct low-rank parts and sparse parts of light field matrix. The simulation result shows that the PSNR of reconstructed image that keeps disparity information among viewpoints of the light field maintains over 25 dB, thus meeting the requirement of sparse sampling for images of light field.

With the improvement of self output power and conversion efficiency, semiconductor lasers have been widely used in laser processing field. Aiming at current requirement for hardening light source of semiconductor laser in laser processing field, a continuous output hardening light source of semiconductor laser with a wavelength of 976 mm was developed. The light source reached higher beam combination efficiency by adopting space / polarization beam combination technique, and better homogenized inherent light intensity fluctuation along slow axis for laser bar by adopting array division of cylindrical micro lens combined with focusing lens, thus making light intensity of focus spots flatly distributed. Finally, the light source was adjusted and tested experimentally. The results show that when the working current is 93 A, the maximum output power of the light source is 5 120 W, the electro-optical conversion efficiency reaches 47%, the spot size is 2 mm×16 mm and the flatness of the spot distribution is over 90%, which meet the requirement for large-scale high efficiency laser hardening in industry.

In order to improve the luminous efficiency of GaN based LED, a novel type LED model which mainly includes Ag grating, transition layer of indium tin oxide and P-GaN grating was designed. The method that using the structure to stimulate surface plasma for improving luminous characteristics of LED was explored, and the processing technology and manufacturing process of the model was discussed. Based on COMSOL software, the LED model was simulated by finite element method, revealing the principle for the variation of normalized radiant power and normalized loss power with wavelength and electric field distribution under different structure parameters. The simulation result shows that when the thickness of the transition layer is 55 nm, period is 270 nm and duty circle is 0.5, the luminous intensity of the GaN based LED is increased nearly 30 times of the normal LED, which lays a reliable foundation for the research of GaN based LED with high performance.

In order to diagnose the inner distribution and movement process of pellet implosion target plasma for laser-driven Inertial Confinement Fusion (ICF) facility, an energy spectrum imaging system based on spherically bent crystal was built. The core element of the system was a spherically bent quartz crystal (1011) with bending radius of 200 mm, of which the lattice structure enabled reflection and the bent surface made focus. The energy spectrum imaging system was performed to first conduct X-ray energy spectrum imaging on SG Ⅲ prototype laser equipment at the Chinese Academy of Engineering Physics (CAEP). Clear X-ray energy spectrum of the high Z element Au plasma was obtained on IP imaging plate. The analysis on the energy spectrum information shows that the energy resolution ratio gained from spherically bent quartz crystal is approximately 1 380, and the error is 39% compared with the theory value of energy spectrum resolution model. The result shows that spherically bent quartz crystal has good energy spectrum resolution capacity.

In view of the nonuniformity of pipe wall thickness of the special pipe under special environments such as high temperature, high pressure, radiation, and others, a method for laser ultrasonic measurement and thickness feature signals processing based on the differential algorithm was proposed. The laser ultrasonic method was adopted with pulse laser excitation and laser interference detection for the experimental measurement of broad-band laser ultrasonic signals of the test piece of pipe. Then the broad-band laser ultrasonic signals were de-noised by average algorithm in order to increase the signal to noise ratio of the original laser ultrasonic signals. Furthermore, the feature of the de-noised ultrasonic signals was extracted by differential algorithm, outputting the laser ultrasonic feature signals of pipe wall thickness. According to the sound velocity of pipe material and the laser ultrasonic transit time, the thickness values for the test piece of pipe wall were deduced. The error between the measured and actual thicknesses was less than 5%. The result shows that the processing method for thickness feature signals based on differential algorithm can provide favorable signal to noise ratio, accurate signal feature quantity and higher measurement accuracy, thus can be used for online real-time measurement of wall thickness of pipe and the thickness nonuniformity leaded by erosion and stress.

For requirements of a high-resolution radar system for wider bandwidths, higher linearity and longer time delays in the echo simulation, a compact Microwave Fiber Delay Line (MFDL) was designed for measurement and calibration of X-band radars. The performance requirements of a radar echo simulator for the distance delay unit was analyzed. The key component, a directly-modulated Distribution Feedback( DFB) laser, was developed according to the system specifications to implement the linear electro-optic conversion of broadband radar signals. Then, a compact reflective delay line structure was designed and realized based on a fiber mirror. Finally, a vector network analyzer was utilized to measure and analyze the microwave transmission properties of the MFDL. Experimental results indicate that the -3dB analog modulation bandwidth of the DFB laser is up to 21 GHz. The MFDL based on the DFB laser provides the time delays by 40 μs, 80 μs, 120 μs for different targets on typical X-band radar test application, in which the in-band amplitude flatness and phase nonlinearity are less than ±0.5 dB and 10°, respectively, and the system dynamic range is larger than 60 dB. The designed MFDL meets the requirement of radar echo in simulation and calibration for additional amplitude errors and phase errors.

When larger aperture holographic plane gratings are fabricated by the holographic exposure method, the homodyne frequency-shifting interference pattern phase locking system usually is used to improve the holographic exposure quality. This paper focuses on the ultra-precision control of the system. Firstly, the principles and structures of a novel homodyne frequency-shifting interference pattern phase locking system were introduced. The high-order linear model was fitted for a nonlinear model of the system based on the theoretical modeling and system identification and a controller of the system was designed by combining the fitting model and the system vibration test result. Then, an actual controlling test was performed based on the design result of the controller to implement the ultra-precision control of the system. Finally, an analysis method on frequency domain was used to explore the effect factors on control precision for the ripple wave in the system. The experiment results demonstrate that the controlling error of the system has reached to ±0.046 1 rad(3σ) and it shows high frequency error ripple wave. The causes of the high frequency error were researched, and the results indicate that limited to the noise, delay of the system and controller parameters, the drift of the interference pattern caused by continuous micro-vibration with a wide frequency range can not be completely restrained by the controller.

An array piezoelectric plate harvester excited by pneumatic compressed air was proposed to implement gas energy conversion and to satisfy the demand of energy supplying for low-power wireless sensors. By converting the alternate high air pressure energy in a pneumatic system into the electric energy with piezoelectric plates, the structure of a prototype for the array piezoelectric plate harvester system was designed. Then, based on the normal working states of the presented harvester, its working principles were introduced and corresponding experiments were performed. The theoretical analysis results show that the array piezoelectric plate has high output voltage capacities and collects the compressed gas energy effectively. An experimental prototype was fabricated by combing a piezoelectric single chip with a diameter of 12 mm and a thickness of 0.2 mm and an air cylinder with a diameter of 63 mm and a travel of 150 mm. A test system was built to research the performance of array piezoelectric plate harvester in simulated gas conditions. In the test, the pressures, cycles and flows were adjusted, respectively. Experimental results at the alternate high air excitation show that the proposed harvester collects the load gas energy of alternate high pressure air, and its optimal load resistance is 600 kΩ and instantaneous power is 1 052 μW, which meets the demands of low power sensors for energy applying.

A current adaptive sliding mode control method based on a disturbance observer was proposed in consideration of the influence of disturbance on the performance of speed servo system in a Permanent Magnet Synchronous Motor(PMSM). An adaptive law was derived to estimate the internal parameter variations and to compensate the disturbance of the model uncertainty. Then, a Sliding Mode Disturbance Observer (SDOB)was designed to estimate the external load disturbance in real time. The estimated values were designed as a feed-forward to compensate the current adaptive sliding mode controller and to further increase the resist-disturbance capacity of the system. The experimental results demonstrate that the system based on the current adaptive sliding mode control and disturbance observer could track the speed command of 900 r/min rapidly and accurately without overshoot, the regulation time is 0.08 s, and the steady-state accuracy is ±5 r/min. When a 0.6 N·m load torque disturbance is added, the method based on current adaptive sliding mode control and disturbance observer gives a maximum speed fluctuation of 21 r/min. As compared with PI control, the speed fluctuation is reduced by 3.4%. The simulation and experimental results indicate that the proposed control method improves the dynamic response and robust performance of the speed servo system and alleviate the chattering of sliding mode control system effectively.

The surface errors in mounting process of a mirror used in the X-ray focusing telescope with a nested conical approximation Wolter-I type structure was simulated and analyzed for an X-ray Timing and Polarization (XTP) satellite. Firstly, the 2-D finite element model was established based on ANSYS. Then, by taking the actual jig and mounting process as loading and boundary conditions, the curvilinear relationship between surface error and loading on three bars was obtained through the analysis of mounting process of the mirror with different radii and the optimized loadings according to different mirrors were selected. Analysis results show that the minimum surface error is less than 0.1 μm according to the optimized loading and satisfies the accuracy requirement. Moreover, the maximum stresses in the mirror are less than the ultimate strength of glass and maintain the reliability in mounting process. A 3-D model was established to compare with the 2-D model for deviation analysis. Results show that the main calculating deviation is 2.3 μm at front and back sections of the mirror in length about 5 mm. The calculating deviation at middle of mirror is less than 0.03 μm. The research show that the 2-D model could be used in the fast surface error analysis and loading confirmation. According to the analysis of mirror mounting process, the accurate mechanics analysis could provide academic bases and references for improving mounting accuracy.

The different grinding characteristics of different crystal faces of a sapphire were compared. A precision grinding test of A-plane, C-plane, M-plane and R-plane for the sapphire was carried out from the grinding force, grinding force ratio, specific grinding energy and surface topography to research their grinding characteristics. Four crystal faces of the sapphire were grinded by a diamond grinding wheel on a precision surface grinder. The grinding forces were measured by a dynamometer, and the grinding force ratio and the specific grinding energy were calculated according to the measured grinding forces. The surface morphology of a workpiece was observed by a scanning electron microscopy. The results indicate that the different faces of the sapphire have different grinding forces, and the C-plane shows the maximum value, followed by the M-plane, A-plane, and the R-plane. The size orders of specific grinding energy are the same as the grinding force. However, the maximum value of grinding force ratio is for the M-plane, followed that by the A-plane and C-plane, and the R-plane is the minimum one. Under the same grinding conditions, the different crystal faces have different grinding material removal modes. The A-plane, M-plane and R-plane are mainly based on brittle fracture, fragmentation and dissociation removal, the crushing pit is larger, and the surface is rough. The C-plane is mainly based on part of the brittle fracture and part of powder removal, the broken crater is smaller, and the surface is relatively smooth. As a results, since the A-plane, C-plane, M-plane and R-plane of the sapphire have different grinding characteristics, they show different grinding mechanisms, grinding forces, grinding force ratios, specific grinding energies and material removal modes.

The way how to reduce the induced drag in an aircraft design was researched and an inverse design method of geometric twist for the aircraft design was proposed to optimize its ratio of lift to drag. By defining the target circulation distribution, the method designed the geometric twists for controlled sections along the wing spanwise to implement the target distribution. A matrix expression for the integro-differential equations of Prandtls lifting-line theory described by Fourier sine series was established. Then, the aerodynamic calculation, aerodynamic spanwise distribution calculation and geometric twist angle inverse design were programmed and a geometric twist wing was designed to achieve elliptical spanwise distribution. Finally, the optimized results were simulated by the forecast of program and Computational Fluid Dynamic (CFD). The simulation results indicate that the lift spanwise distribution of twisted wing is elliptic, the induced drag and total drag are decreased by 17.07% and 15.43%, respectively, and the ratio of lift to drag is improved by 6.5%. This method aims at controlled sections, shows better realizability, and gives out a reference for engineering applications.

For problems of poor linearity and too many inter-dimensional coupling errors of a four-point supporting piezoelectric six-dimensional force sensor, the decoupling algorithms based on Redial Basis Function (RBF) neural network were proposed. Main factors to produce coupling errors were analyzed and the RBF neural network was established. The six-dimensional force sensor was calibrated experimentally to obtain experimental data for decoupling, and the data were processed by the nonlinear decoupling algorithm based on RBF neural network. Then the mapping relation between input and output was acquired by decoupling and the decoupled data from the sensor was obtained. These data were analyzed, and the result shows that the biggest classⅠerror and classⅡerror by the proposed nonlinear decoupling algorithm based on RBF neural network are 1.29% and 1.56% respectively. The experimental analysis shows that it will effectively reduce the classⅠerrors and the classⅡerrors through nonlinear decoupling algorithm based on RBF neural network, and meets the requirements that the two kinds of error indicators of the sensor should be less than 2%.The proposed algorithm improves the measuring accuracy of sensors and overcomes the difficulty on decoupling.

A shoe-mounted piezoelectric energy harvester was designed to collecting energy from human walking. This energy harvester comprises of four piezoelectric cantilever beams magnetically coupled with a spring-mass system. The spring-quality system could sense the acceleration excitation along a radial bone shaft and generate electricity through the magnetic coupling driving a piezoelectric element. The expression of acceleration signals was obtained by fitting the experimental data. And then, a simulation model was established to simulate the power generation performance of the energy harvester. Finally, a prototype was also fabricated and its performance was verified by an experimental test. The results indicate that the four beams could be triggered several times by the spring-mass system within one step when the energy harvester is excited by the acceleration along the tibial axis, and several piezoelectric beam voltage outputs could be obtained. Furthermore, the power-generating capacity of the piezoelectric beam excited by the coupled accelerations is always better than that excited by the single direction acceleration. When walking speed ranges from 2 km/h to 8 km/h, the peak voltage output from each beam is as large as 10 V. The piezoelectric energy harvester collects the energy from human walking in low frequency and the superposition of voltage outputs generated by accelerations comes from two orthogonal directions, so that the power-generating capacity is improved greatly.

The effect of mass unbalanced moment under high-frequency vibration of a helicopter on the performance of a photoelectrical stabilized platform was discussed. A system model based feedforward compensation method for mass unbalanced moment was proposed on the basis of a three closed-loop control system with current feedback, velocity feedback and position feedback on the traditional photoelectrical stabilized platform. By calibrating the mass eccentricity of the platform, the acceleration signals of the platform were obtained by a acceleration sensor to perform the feedforward compensation to suppress the mass unbalanced moment of the platform. The experiment results show that the disturbance isolation increases at least 6.4 dB after inducing the feedforward compensation system as compared with that of the traditional three closed-loop control system. Moreover, as compared with that of compensation scheme using a disturbance observer, the proposed photoelectrical stabilized platform system with the feedforward compensation not only increases its compensation ability about 12.9 dB at low-frequency, but also overcomes the problems that disturbance observer can not compensate mass unbalanced moment at high-frequency. It increases greatly the disturbance isolation at full frequencies, allows the visual axis to better keep in an inertial space and shows high practical values.

For the lever arm translational motion and equivalent coning rotation of a ship-borne optical detection system under a great hull attitude, a compound Electronic Image Stabilization(EIS) method which brought inertial information was proposed to compensate the coupled disturbance. Firstly, the equivalent coning rotation existed in the LOS (Line Of Sight) stabilization process was analyzed based on a pitch-yaw optical stabilization system, and the relationship between LOS rotation angle and platform roll angle was deduced. Then, the influence of lever arm disturbance on weak spots was analyzed and a coupled disturbance model combined with the equivalent coning rotation was built. On the basis of the model, a compound image stabilization method by combing inertial information and the EIS method was proposed to realize the image stabilization under a low characteristic environment. Finally, the image stabilization and real time ability of the proposed method were verified through hardware-in-the-loop simulation under the low characteristic environment. The results demonstrate that the method compensates the coupled disturbance from the lever arm translational motion and equivalent coning rotation. It has higher image stabilization and real time ability, and motion estimation is at a sub-pixel level. After compensation, the peak signal-to-noise ratio (PSNR) of image stabilization improves by 4 dB on average. It satisfies the requirements of ship-borne optical imaging systems for strong instantaneity, high precision, strong anti-interference and stable and reliable characteristics.

In target detection on aerospace optical remote sensing, due to the interference of uncertain conditions on sea surface such as atmosphere, solar radiation, cloud and mist, islands and others, traditional ship detection methods always have some defects such as low detection efficiency, poor reliability. Therefore, the author proposed an unsupervised ship automatic detection method. In this method, visual saliency was combined with multi-saliency detection model for fast searching of sea-surface targets; after saliency map was generated, a rough segmentation was conducted on it, then extracted target slice was marked and fine segmentation was implemented, subsequently, improved Hough transformation was used to rotate principal axis of target for ensuring the symmetry of targets to Y axis; the characteristics of gradient direction was applied to recognize phony targets such as thick clouds layer, islands and others that may be detected, the gradient and amplitude statistical value of those targets in 8 intervals on all directions were judged to identify target ships and warships and eliminate phony targets. The experimental result indicates that the detection method of ships and warships can be used to successfully extract target ships and warships which are in different size and random distributed on sea surface for obtaining accurate quantity and location information about them. In test on a large number of authentic optical remote sensing pictures, the detection accuracy rate of proposed method is higher than 93%, while the false alarm rate is lower than 4% through target identification and treatment and phony target elimination, which has strong robustness.

Aiming at failure detection problems on subtle region caused by saliency differences of detected target in local region, under the framework of Bayesian theory, the author proposed a novel salient region detection method based on cellular automata multi-scale optimization. Firstly, the prior information about dark channel was integrated with regional contrast to separately construct original salient maps in five superpixel scale spaces on the same picture; and then the cellular automata was used to establish a dynamic updating mechanism and impact factor matrix and confidence matrix were applied to optimize influences of each cellular in next state. As a result, the saliency values of all cells will be renovated simultaneously according to the proposed updating rule, and five optimized salient maps were obtained; finally, under the framework of fusion algorithm in Bayesian theory, the final saliency map was obtained. The experiment on two standard image datasets with different complexity was conducted, and experimental result indicates that the performance of proposed algorithm is superior to other ten existing salient region detection algorithms both in visual effect and in objective quantitative comparison. Especially on the most challenging DUT-OMRON data base, the aggregative indicator F-measure value of proposed algorithm is 0.631 4, and mean absolute error (MAE) is 0.132 5 and ROC area under the curve (AUC) is 0.892 8, indicating that the algorithm has higher accuracy and robustness.

Aiming at problem that segmentation threshold value of a ferrographic image is difficult to select in oil monitoring, a self-adaptive ferrographic image segmentation algorithm based on difference quotient was introduced. Firstly, the ferrographic abrasive particle image was converted into three-dimensional grey histogram and then a slice analysis was made on it; then, by introducing Newton interpolation polynomial, the pixel number obtained from different slices was took as interpolating point of slice grayscale-frequency curve; the first kind of acceptable function and the second kind of acceptable function were established based on difference quotient, and two kinds of errors were identified by combination of experimental data. The minimum gray value which simultaneously satisfied the two kinds of errors was selected as segmentation threshold value. Finally, segmentation experiments on different types of ferrographic images and ferrographic images with Gaussian noise and salt & pepper noise were conducted to compare the performance of proposed algorithm and three classical algorithms including iterated thresholding method, Otsu algorithm and maximum entropy. The experimental result indicates that the proposed algorithm is rarely interfered by noise and its average false positive rate and average omission rate is overall superior to other three algorithms. Through conducting feature extraction on ferrographic image and identification by support vector machine, it can be found that the proposed method has the highest identification accuracy rate on three faulted abrasive particles, which reaches 82.86%. Although there are no obvious advantages on operation time, but the method has optimal comprehensive property and can meet the requirement for making a self-adaptive segmentation on ferrographic image in the process of oil monitoring.

To solve measurement problem of relative attitude and position for non-cooperative spacecraft in on-orbit capture, an autonomous measuring method for relative attitude and position of spatial non-cooperative spacecraft based on stereo vision was proposed. Main body of spacecraft and satellite-rocket docking ring were taken as recognition features in this method, and no staff was needed to participate in the recognition process; meanwhile, a feature matching method based on spatial geometry constraint was introduced. With the guidance of spatial geometry constraint, three-dimensional information of features was directly obtained at the time of completing matching to realize integration of feature matching and reconstitution; finally, the relative attitude and position of spacecraft were calculated according to spatial vectors, and calculation accuracy was improved via fully utilizing redundant information. Experimental result shows on condition of main body of spacecraft at 280 mm and relative distance at 2 m, attitude and position measurement error of the proposed method are less than 1.5° and 4 mm respectively, satisfying on-orbit capture measurement requirements of relative attitude and position for spatial non-cooperative spacecraft.

Due to the proximity of the optical diffracting limitation, the edges of the stripes in micrometer scale are blurred after magnification by the optical microscope. Together with the uneven illumination caused by coaxial lighting source, the stripe image quality is very poor. To effectively measure the stripe distance between two stripes in micrometer scale, a centerline extraction algorithm was proposed. First, a single scale Retinex model was adopted to enhance the original image to overcome inaccurate segmentation caused by uneven illumination. After that, binary segmentation was conducted on the enhanced image via optimal threshold value of Ostu. Then, directing at the phenomenon that there was much rag and hollow at the boundary of stripes after segmentation, a boundary collapse method based on fast marching algorithm was utilized to extract centerline accurately. Finally, least square fitting method was conducted to fit the extracted centerlines. Experimental results show that the proposed method can effectively realize accurate extraction of stripe centerline in microscopic image with micrometer scale; the maximum measured deviation of this method is less than 2% when it is used for measuring stripe distance between two stripes with standard width.

The imaging characteristics of an image with light spots and the grey-level distribution model of an ideal light spot were analyzed. A fast and accurate algorithm to detect simultaneously multiple light spot centers in a complex imaging environment was proposed for the image with multi-scale light spots. As the centers of light spots would not be changed after blurring the spot image with Gaussian kernels, the image with massive multi-scale light spots was blurred firstly with multilevel Gaussian kernels to fast establish a Gaussian scale-space of the spot image. Then an efficient non-maximum suppression algorithm was applied to find local extremums in multiple scales and to determine the pixel level coordinates of the light spot centers in the scale-space preliminarily. Finally, combined with the neighboring pixels of these pixel level coordinates, sub-pixel accurate locations of the spot centers were obtained by local surface fitting. The validity of proposed algorithm was verified by simulation and experiments. The results for an image of 640 pixel ×480 pixel show that the processing time is 50 ms, average detection time for per thousand light spots is only 23 ms and the detection accuracy is 89% in many complex situations. Moreover, the algorithm is sensitive to low-light spots and can process the images with different scale spots in low contrast scenes, usually offering a low error rate and miss rate. Due to the high detection speed and good stabilitiy, the proposed algorithm performs well in real vision measurement systems.

Optimization selection of test points is an important step of testability design for complex equipment, so a Discrete Firefly Algorithm(DFA) used for solving optimization selection problem of test points was proposed. First of all, the mathematical model of optimization selection problem of test points was built, then discretization improvement was conducted on the traditional firefly algorithm, and the implementation steps of the DFA were given, later the effect of different attraction functions and binarization functions (sigmoid and tanh functions) on the result of the algorithms was also analyzed. Finally, The DFA was applied to five real systems with different sizes to verify the effectiveness, and the computational efficiency of DFA was compared with particle swarm optimization (PSO) and genetic algorithm (GA). In premise of complying with fault detection rate and fault isolation rate the system requires, optimal value of test cost for 5 systems from proposed DFA respectively reduced by 10.1% and 14.6% compared with PSO algorithm and GA algorithm. The experimental result shows: DFA can quickly converge to the global optimal solution of higher quality, and it can avoid trapping into local optimal solution, so it has very good application prospect to solve optimization solution problem of test points for large-scale complex equipment.

Ground Wide Angle Cameras (GWAC) of the astronomy satellite SVOM contains 36 wide-angle telescopes, and its high-precision automatic observation of short exposure is established on real-time auto-focusing, in this paper, we focus on the research and realization of image definition evaluation for real-time auto-focusing on GWAC. At first, principles of image definition evaluation methods of common telescope and applicability on GWAC system were researched, thus two kinds of methods based on encircled energy of star image were obtained, namely radius of 50% energy of stars and the full width of half maximum (FWHM) of point spread function (PSF), were suitable for GWAC system. Different from time-consuming algorithm of common astronomy software package IRAF, method of calculating FWHM via PSF fitting calculation based on source intensity distribution was proposed, and further influence of key method parameters such as fitting model, star-choosing standard, centring precision, fitting radius, interpolation method, imterpolation interval, FWHM after-treatment, etc on calcu-lation precision and speed of FWHM was researched. A set of definition evaluation methods that are applicable to GWAC real-time automatic focusing were acquired in the last, and it is realized by C++ programming. Calculation error of FWHM method in the paper is 0046 pixel, the precision is equal to IRAF approximately and calculated focus location is the same; calculation time of single graph (about 300 stars after selection) is 0.67 s which is 1/20 of calculation time for IRAF. It satisfies precision and real-time requirements of automatic focusing for GWAC system. The research results havebeen applied in GWAC system and provide reference for other automatic observing system of telescope.

In order to provide effective foundation for retinal image registration, illumination adjustment and pathological detection of retina interior and other problems, a fully automatic method of detecting and recognizing blood vessel for color retina fundus images effectively was proposed. Aimed at the state with elongated tubular shape and preferably linear structure in local part of visible blood vessel, combinatorial shifted filter response model that is applicable to strip structure was used for feature extraction. Taking different features of blood vessel and the end of blood vessel into consideration, two types of filtering modes with symmetry and dissymmetry were configured for tracking, feature vector library was established by response acquired from combinatorial shifting filter response model (symmetry and dissymmetry) and G channel pixel value together and each pixel was classified and determined by AdaBoost classifier. The experimental result based on international public database DRIVE and STARE shows that the segmentation result of proposed method on two standard databases (DRIVE: Accuracy=0.948 9, Sensitivity=0.765 7, Specificity=0.980 9; STARE: Accuracy=0.956 7, Sensitivity=0.771 7, Specificity=0.976 6) is better than existing methods. It is applicable to computer-assisted quantitative analysis of color retina fundus images and can be used as clinical reference.

In astronomical image denoising, to improve denoising construction performance of iterative curvelet threshold (ICT)algorithm, a compressed sensing iterative reconstruction algorithm by combining cycle spinning and curvelet wiener filtering was proposed. Firstly, cycle spinning method based on curvelet threshold was used to adjust reconstructed images for inhibiting Pseudo-gibbs effect of reconstructed images; then, proposed curvelet wiener filtering operators were used to replace wavelet threshold for sieving image curvelet coefficient to further improve the quality of reconstructed image. The reconstruction experiment on Lena image and moon image with Gaussian white noise was conducted, and the result shows that compared with traditional compressed sensing ICT algorithm, the peak signal noise ratio of proposed algorithm increases by 2.6~3.2 dB approximately. So the proposed method can acquire better denoising performance, and can protect detail information of astronomical images effectively.

An experiment of ms laser pulse irradiation on monocrystal silicon was performed. The real-time stress damage from the interaction between ms laser pulse with monocrystal silicon was measured by Mach-Zehnder interferometry. A digital simulation model for ms laser pulse irradiation on monocrystal silicon was established by COMSOL Multiphysics finite element method. The evolution law of a stress field with time under the same pulse width and different energy densities was explored when the monocrystal silicon was irradiated by ms laser pulse from theory and experiments. The processing method for interference fringes was researched and the 45°projection method was proposed to calculate the stress values of materials in different directions based on the traditional x axis projection method. Based on the numerical simulation results, the experimental results of the two methods were compared and analyzed. It shows that the error from the experimental results of the x axis projection method is in 9.5%—29.3% and that from the 45°projection method is in 0.1%—22.6% as compared with that of numerical simulation results. It is verified that the method of 45°projection is more accurate for the processing of interference fringes in the experiment of measuring the real-time stress damage by the Mach-Zehnder. The experimental results provide the theoretical and experimental guidance for the study of the stress damage of monocrystal silicon.