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Issue 5 ， 2017
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Measurement of OH and CH radicals in micro-jet flames using planar laser induced fluorescence and CH filter
Abstract：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 H 2 and CH4 as fuels and to measure the spatial distribution of two important radicals, CH and OH. Firstly, the effect of exposure time of Keywords：optical measurement;laser spectrum;planar laser induced fluorescence;micro-jet flame;OH;CH- 115
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Published：2020-07-07 -
Polarimetric calibration of multi-channel polarimetric imager
Abstract：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 lense Keywords：polarimetric calibration;polarimetric imager;multi-channel;Mueller matrix;polarimetric effect- 169
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Published：2020-07-07 -
Dynamic detection and recognition of welded defects based on magneto-optical imaging
Abstract：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 Keywords：dynamic magneto-optical imaging;welded defect;alternating magnetic field;pattern recognition- 461
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Published：2020-07-07 -
Thickness measurement of lubricant film by optical coherence tomography
Abstract：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.Keywords：Optical Coherence Tomography(OCT);lubricant film;thickness measurement;spectral-domain;decouple- 86
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Published：2020-07-07 -
Highly precise ground certification system of satellite laser communication
Abstract：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 satel Keywords：laser communication;ground verification system;satellite platform disturbance;following error;beam pointing control- 69
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Published：2020-07-07 -
Single-view XLCT imaging based on fast Bayesian matching pursuit
Abstract：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 construct Keywords：optical molecular imaging;X-ray luminescence computed tomography;single-view reconstruction;Bayesian matching pursuit;iterative-shrinking permissible region- 176
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Published：2020-07-07 -
Sparse sampling and reconstruction of compressive light field via low-rank matrix decomposition
Abstract：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 Keywords：computational imaging;light field imaging;low rank and sparse decomposition;compressive sampling;images reconstruction- 187
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Published：2020-07-07 -
Development of 5kW diode laser hardening source with homogenized intensity distribution
Abstract：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 Keywords：laser processing;high power diode laser;laser source;laser hardening;beam combination- 71
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Published：2020-07-07 -
Improving LED luminescence properties by using Ag/P-GaN double grating
Abstract：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.Keywords：light-emitting diode;surface plasmon;luminous efficiency;grating;radiation power- 223
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Published：2020-07-07 -
X-ray spectral diagnosis for laser plasma
Abstract：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 spec Keywords：spectroscopy;spherically bent crystal;X-ray imaging;spectral resolution- 68
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Published：2020-07-07 -
Laser ultrasonic signal processing by differential algorithm in special pipeline thickness measurement
Abstract：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-b Keywords：laser ultrasound;special pipeline measurement;signal de-noising;differential algorithm;feature extraction- 69
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Published：2020-07-07 -
Compact microwave fiber delay line for radar echo simulation
Abstract：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 conver Keywords：radar echo simulation;fiber delay line;Distribution Feedback(DFB) laser;wideband;time delay;linearity- 64
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Published：2020-07-07
Modern Applied Optics
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Ultra-precision control of homodyne frequency-shifting interference pattern phase locking system
Abstract：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 b Keywords：holographic exposure;homodyne frequency-shifting interference pattern phase locking system;system identification;high order linear fitting;micro-vibration;PID control- 84
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Published：2020-07-07 -
Array piezoelectric plate harvester excited by pneumatic compressed air
Abstract：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 principle Keywords：piezoelectric plate harvester;pneumatic compressed air;array piezoelectric plate;pressure fluctuation;energy transmition- 68
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- 19
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Published：2020-07-07 -
Current adaptive sliding mode control based on disturbance observer for permanent magnet synchronous motor
Abstract：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 design Keywords：Permanent Magnet Synchronous Motor(PMSM);adaptive sliding mode control;disturbance observer;current control- 122
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Published：2020-07-07 -
Numerical simulation and analysis of X-ray focusing telescope in mounting process
Abstract：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 pr Keywords：X-ray focusing telescope;mirror mounting;surface error;loading analysis;finite element method- 93
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Published：2020-07-07 -
Comparison of grinding characteristics of different crystal surfaces for sapphire
Abstract：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 f Keywords：sapphire;crystal surface;grinding force;grinding characteristics;surface topography- 121
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Published：2020-07-07 -
Drag-reduction inverse design of wings based on lifting-line theory
Abstract：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 establi Keywords：wing design;inverse design;lifting-line theory;circulation distribution;geometric twist;induced drag- 91
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Published：2020-07-07 -
Decoupling algorithms for piezoelectric six-dimensional force sensor based on RBF neural network
Abstract：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 Keywords：six-dimensional force sensor;piezoelectric sensor;Radial Basis Function (RBF) neural network;decoupling algorithm- 103
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Published：2020-07-07 -
Shoe-mounted piezoelectric energy harvester for collecting energy from human walking
Abstract：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 mode Keywords：piezoelectric energy harvester;piezoelectric effect;human gait;energy harvesting;frequency up-conversion;bistable structure- 105
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Published：2020-07-07 -
Feedforward compensation of mass unbalance moment for airborne photoelectric stabilized platform
Abstract：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 plat Keywords：photoelectric stabilized platform;mass unbalance moment;feedforward compensation;high-frequency vibration;disturbance isolation- 116
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- 5
Published：2020-07-07
Micro/Nano Technology and Fine Mechanics
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Compound image stabilization for coupled disturbance in ship-borne imaging system
Abstract：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 ang Keywords：high precision imaging;ship-borne imaging;coning rotation;lever-arm translation;electronic image stabilization;compound image stabilization- 85
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Published：2020-07-07 -
Detection and identification of unsupervised ships and warships on sea surface based on visual saliency
Abstract：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; aft Keywords：computer vision;detection on ships and warships;visual attention mechanism;saliency area;characteristics of gradient direction- 112
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Published：2020-07-07 -
Salient subtle region accurate detection via cellular automata multi-scale optimization
Abstract：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 establis Keywords：cellular automation;visual saliency;multi-scale superpixel;dark channel;Bayesian theory- 86
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Published：2020-07-07 -
Self-adaptive segmentation of oil monitoring ferrographic image based on difference quotient
Abstract：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 gray Keywords：oil monitoring;ferrographic image;different quotient;image segmentation- 82
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Published：2020-07-07 -
Autonomous measurement of relative attitude and position for spatial non-cooperative spacecraft based on stereo vision
Abstract：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 in Keywords：on-orbit capture;measurement of attitude and position;non-cooperative spacecraft;spatial geometry constraint- 91
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Published：2020-07-07 -
Centerline extraction of stripe imaged by optical microscope
Abstract：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 seg Keywords：microscopic image;stripes;centerline extraction;fast marching method;retinex;boundary collapse- 67
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Published：2020-07-07 -
Fast and accurate detection of multi-scale light spot centers
Abstract：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 Keywords：machine vision;light spot center detection;Gaussian blur;accurate location- 83
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Published：2020-07-07 -
Optimization selection of test points on complex equipment for discrete firefly algorithm
Abstract：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 binar Keywords：testability design;pptimization selection of test point;firefly algorithm;metaheuristic algorithms- 96
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Published：2020-07-07 -
Definition evaluation method for real-time auto-focusing of wide-angle telescope
Abstract：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 Keywords：image resolution;automatic focusing;point spread function;wide-angle telescope;energy concentration degree- 80
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Published：2020-07-07 -
Automatic detection method of blood vessel for color retina fundus images
Abstract：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 ext Keywords：retinal image analysis;vessel segmentation;combinatorial shifting filter response model;AdaBoost classifier- 86
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Published：2020-07-07 -
Astronomical image denoising with compressed sensing and curvelet
Abstract：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.Keywords：thresholding denoising;pseudo-gibbs;curvelet wiener filtering;astronomical image- 78
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Published：2020-07-07 -
Measurement of real-time stress damage of monocrystal silicon by Mach-Zehnder interferometry
Abstract：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 Keywords：interaction of laser beam and material;monocrystal silicon;ms pulse laser;real-time stress damage;Mach-Zehnder interferometry- 95
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Published：2020-07-07
Information Sciences
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