Chinese Version Light学术出版中心
Latest Issue
Issue 8 ， 2009
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Numerical analysis and measurement method of stray light for UV ruled gratings
Abstract：As one of important technical specifications of diffraction gratings, stray light directly affects SNR; especially it is harmful to spectrum analysis in UV spectrum. In order to search stray light arising from applications of ruled gratings in the spectrometer, basing on classical Fresnel-Kirchhoff diffraction equation, we deduce equations of relative intensity of stray light and analyze forming causes of stray light in theory. The numerical simulation indicates that random errors in the spacing of the grating grooves and random errors in the depth of the grooves for UV ruled gratings are the main source of stray light; moreover, small-scale random surface roughness affects stray light slightly. Otherwise, we establish the concept of relative width of exit slit and find the relation between height and relative width of exit slit and intensity of stray light. This analysis method, as a theoretical reference, is used to reduce the stray light in the process of fabricating grating essentially and can be applied to reduce the stray light in practice. Finally, in order to compare theory results with experimental results measured by filter method, we present equation which solves the total stray light and measure stray light of four wavelengths by U.V.-visible spectrophotometer. It approves that the maximal relative error between theory results and experimental results is about 13%.Keywords：diffraction grating;stray light;analytical method- 40
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Published：2020-08-12 -
Theory Analysis and the Experiment of Crosstalk on Grating Light Modulator Array
Abstract：Grating Light Modulator (GLM) based on Micro-Electro-Mechanical Systems (MEMS) is applied in projection display. In order to discuss the influence of crosstalk on the GLM driven by passive matrix, operation principle of GLM is presented, and electrics model of passive matrix addressing GLM is established. According to Kirchhoff’s Current Law(KCL) and Kirchhoff’s Voltage Law(KVL), passive matrix addressing for the device is analyzed and simplified. The voltage relationship between half-select pixel, non-select pixel and total-select pixel is achieved. It’s indicated that half-select pixel is influenced greatly by crosstalk, and crosstalk is more serious by increasing the array. The relationship between the ±1 order diffractive intensity of those three kinds of pixels and driving voltage of total-select pixel respectively is gained by the experiment. The result of the experiment shows that the voltage of half-select pixel is approximately half of the voltage of total-select pixel, and is much larger than the voltage of non-select pixel. The result validates the correctness of the theory. It is proved that active matrix addressing is the optimal method for restraining crosstalk.Keywords：MEMS;Grating Light Modulator;crosstalk;passive matrix addressing- 36
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Published：2020-08-12 -
Study on characteristics of the liquid crystal variable retarder attached with the compensator
Abstract：In order to measure the retardation of the liquid crystal variable retarder(LCVR) attached with the compensator, a new method is presented in this paper, which is based on Stokes vector and Mueller matrix. This method is simple, precise and no mechanism rotating. A 2 kHz square wave of adjustable amplitude 0-10V is used to control LCVR and the retardation is measured at six wavelengths. The experiment results show that LCVR has the advantages of low voltage controlling, simple operation, wide adjustment range and no need rotating. The error of measurement is less than 0.6%. The fitting function is established based on the characteristics of the retarders. The method of the least-square curve fitting is used to obtain retardation of all wavelengths and all voltages in the working condition of the retarders. The standard error of curve fitting is less than 0.02λ. The measurement method, the experiment results and the fitting function are useful for the polarization device research.Keywords：liquid crystal variable retarder;compensator;Stokes vector;Mueller matrix;curve fitting- 42
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Published：2020-08-12 -
EPICS-Based Motion Control System of SSRF-X SAXS
Abstract：This paper describes the motion control system for SSRF-X SAXS station. The system is a distributed control system, which is recognized as the “standard model” in large accelerator laboratories in the world and is developed based on the large-scale software EPICS (Experimental Physics and Industrial Control System). The system implements the motion control of two four-jaw slits, two slit-bases, sample-stage and beamstop and their resolution test are implemented.Keywords：SSRF;SAXS;motion control;EPICS- 33
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Published：2020-08-12 -
Detection and simulation of multi-spectral TDI CCD signal for space optics remote sensing device
Abstract：A method of high speed and parallel CCD control signal detection and simulative sequential video signal output is presented in order to get a reasonable design and an application of space optics remote sensing system with high-performance multi-spectral TDI CCD image sensor. At the line readout and transfer period of 200µs, 48 clock drivers and 31 DC bias signals are analyzed and detected simultaneously. At the same time, the prepared image data are transmitted fast from disk array to video image generator which is composed of FPAG, D/A, amplifier and denoise circuit, through PCI-X and LVDS bus. Sequential and real-time output of diversified testing video images is realizes. It is shown with experiments that three simulative chromatic video signals at frequency of 6MHz and eight simulative panchromatic video signals at frequency of 12MHz are generated synchronously and reliably. The reference voltage of video signal is 8V and amplitude range is 0~1.7V. The design requests are met for the valid sampling time and signal stabilization.Keywords：space optics remote sensing;multi-spectral;TDI CCD signal;detection and simulation- 32
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Published：2020-08-12 -
Argon-puff Z-pinch implosion plasma temperature diagnostics
Abstract：The line ratios between dielectronic recombination satellites and the w-resonance are analyzed as a function of plasma temperature for temperature diagnostics. The n=2—1 spectral emission pattern of heliumlike argon, together with the associated satellite emission originating from lithiumlike argon have been measured with x-ray elliptical curved crystal spectrometer on Yang accelerator. Experimental results using curved Mica crystal analyzer are described and show spectrum of argon-puff Z-pinch plasma. Spectra showing the He-like resonance line w and the satellites j, k, q, the magnetic quadrupole M2 line, the intercombination line y, the forbidden line z and a cold Kα line of argon were recorded with X-ray film. The line ratios between dielectronic recombination satellites ( j+z, k) and the w-resonance line were found and a good agreement between the theoretical models and the experimental results, supporting the method of line-ratio measurement as a temperature diagnostic for plasmas.Keywords：Z-pinch;X-ray spectrum;plasma;electron-temperature- 43
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Published：2020-08-12 -
Ring cavity all fiber F-P interferometer used in detection of acoustic emission
Abstract：Proposed the ring cavity all fiber F-P interferometer used in AE (acoustic emission) detection. By welding the incidence and the exit of the 2×2 optical fiber coupler directly, structure the optical fiber ring cavity, it can be attached or embed in the measured solid to detect the AE signals. Determined the detection property of the optical fiber sensor through the theoretical derivation and the simulation of computer. PZT (Piezoelectric Ceramic) is powered by signal generator as the continuous known ultrasonic source, and the blast wave that is adopted to simulate the burst AE signal in marble slab, they were used to be detected by the optical fiber sensor, and then the characteristic frequency of acoustic emission signal is obtained by Fourier technique. The experimental results indicate that the system can detect acoustic emission signals that cause the optical fiber stretching to 10-8m in axial direction and identify the characteristic frequency of it, this optical fiber sensor works without the match of optical path and apply to monitor the large scale component. It provides a new method for the health examination and the monitoring for material structure.Keywords：acoustic emission detection;optical fiber sensor;F-P interferometer;characteristic frequency- 29
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Published：2020-08-12 -
A Study on the Dynamical Characteristics of Distributed Feedback Fiber Laser
Abstract：In the study on the application of DFB fiber laser to underwater sound detecting, it was found that the acoustic pressure sensitivity of the DFB fiber laser was higher than that calculated under hydrostatic boundary conditions, and its frequency response curve was not smooth. However, the reason and the mechanism were to be figured out. Accordingly, dynamical characteristics of the DFB fiber laser were investigated. Firstly, a DFB fiber laser, whose both ends were fixed, and the cavity was tensioned and placed in air and water respectively, was analyzed numerically. And then, with specially designed testing assemblies, experimental study on it was also conducted. And the results indicate that the first natural frequency of the DFB fiber laser is related to the length of the optical fiber between the two fixed ends, and the length increases, the frequency decreases. When the length has been specified as 50 mm, 55 mm and 60 mm respectively, the first natural frequencies have been found to be about 250 Hz, 200 Hz and 125 Hz in air, and 200 Hz, 160 Hz and 120 Hz in water, correspondingly. It shows that when vibration is taking place in the DFB fiber laser, fluctuation in its output will be resulted, and the first natural frequency is an important factor of it.- 50
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Published：2020-08-12 -
Selection of the efficient wavelength regions in FT-NIR spectroscopy for determination of free amino acid content in tea
Abstract：In determination of free amino acid content in tea by FT-NIR spectroscopy, in order to improve its precision and robustness, it attempted to build predictive model by the efficient spectral region selection and PLS algorithm. In this research, synergy interval partial least-squares (siPLS) and genetic algorithm partial least-squares (GA-PLS) were applied to select the efficient spectral regions. The number of PLS components and the number of intervals were optimized according to cross-validation in calibration set. The performance of the final model was evaluated according to root mean square error of prediction (RMSEP) and correlation coefficient (R) in prediction and calibration sets. Experimental results showed that the two methods were able to produce better prediction models in relation to the full-spectrum model, and the performance of siPLS model was better than GA-PLS. The optimal model was achieved with R= 0.9542 and RMSEP =0.2560 in prediction set. This study demonstrated that NIR spectroscopy with efficient selection wavelength regions algorithm could be used successfully to analyze free amino acid content in tea, and revealed superiority of siPLS algorithm in contrast with other multivariate calibration methods.Keywords：near infrared;efficient selection wavelength regions;partial least-squares;tea- 67
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Published：2020-08-12 -
Phase-Locking of Two Fiber Lasers Based On a Beam Splitter
Abstract：A phase-locking methold of two individual fiber lasers based on a beam splitter with reflectivity of 50% at 45° is proposed and the phase-locking principle is analyzed in detail. Phase-locking of two individual double clad fiber lasers is experimentally demonstrated, 360mW output power is achieved with the power combining efficiency is about 73%, and the on-axis power intensity is greatly enhanced. The phase-locking approach is simple and no power-limitation optical components were utilized, the output power can be further up scaled and it is one of the most promising phase-locking technologies in high-power fiber laser coherent combination field.Keywords：fiber laser;coherent combining;beam splitter- 26
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Published：2020-08-12 -
Measurement and Analysis of Diffuser Panel characteristics used for On-board Calibration for Satellite Optical Sensors
Abstract：The optical properties, including directional/hemisphere reflectance(DHR), bidirectional reflectance factor (BRF)and bidirectional reflectance distribution function(BRDF) of diffuser panel used for onboard calibration for satellite optic sensors ,were measured. And, in order to investigate the stability and the adaptability of the panel under on-orbit environment, series of environment simulation tests were performed . As the results indicated : The reflectance achieve 0.99 at VNIR,0.95 at SWIR; and the differences of the reflectance at VNIR are within 0.01.The variety of BRF(10°~60°) and BRDF (0°~60°) are less than 0.1,0.048,respectively，and this Lambertian property of diffuser panel is independence to spectral band and UV radiation. Atomic oxygen exposure or proton bombardment has little effect on diffuser panel’s optical properties; Some degradation of optical properties under UV radiation has been linked to degradation of organic contaminants, but this contaminants can be prevented by improvement of production protocol. The diffuser panel have gone through on-orbit level mechanical environment tests. So, high reflectance, spectral flatness, Lambertian characteristics and stability in orbit of the diffuser panel were tested, which can satisfy space application.Keywords：Remote Sensing;Diffuser used for on-board calibration;Measurement and Analysis;Reflectance factor;BRDF- 34
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Published：2020-08-12 -
Magnetorheological Finishing (MRF) for High-Precision Optical Surface
Abstract：Abstract: As a deterministic sub-aperture magnetically assisted polishing method, Magnetorheological Finishing (MRF) has the ability to produce optical surfaces with high accuracy on a wide variety of shapes. This paper mainly introduces fundamental principle of MRF and summarizes some key problems in MRF process. Using KDMRF-1000 MRF polishing machine and KDMRW-1 water based MR fluids, one K4 flat work piece (100 mm in diameter) and one K9 sphere work piece (200 mm in diameter) are polished. Finally, work piece one is 55.3nm peak-to-valley (PV) value, 5.5nm root-mean-square (RMS) value and work piece two is 40.5nm PV value and 5nm RMS. Also, surface roughnesses of two work pieces are improved obviously. Keywords: Magnetorheological Finishing (MRF), MR Fluids, High-Precision Optical SurfaceKeywords：Magnetorheological Finishing (MRF);High-Precision Optical Surfaces- 47
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Published：2020-08-12 -
Machine Vision Algorithm Based on the Weighted Least Square Method
Abstract：In order to improve the accuracy of the recovered object, this paper proposed a new algorithm. This algorithm tries to express the machine vision model by parameter equation. Based on this parameter equation, this paper proposed a kind of weighted least square method. It is well know that the recovered accuracy will be changed by the camera’s position. But the original algorithm neglects this, and uses the least square method to fit the point with the minimal error. Aim at this defect, this paper weighted the least square method according to different position, and use parameter equation to express the machine vision model. This algorithm improved the recovered accuracy. The crucial step of the weighted least square method is to evaluate the weight. At the end of this paper, the experiment verified the efficiency of the algorithm.- 27
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Published：2020-08-12 -
Design of a four-arm MEMS microgripper integrated with force sensor
Abstract：In order to realize the monolithically fabrication and control the gripping force, a novel four-arm structure single crystal silicon MEMS gripper integrated with force sensor is successfully developed using silicon bulk machining. Based on the technology of the piezoresistive detection, an effective technique of fabricating vertical sidewall piezoresistor in plane is used to fabricate the piezoresistor in the end of the end-effectors. Finite element analysis (FEA) is used to analyze the structure of the gripper and the flexible beams of the force sensors. The comb microactuator generates a linear horizontal motion, which is converted into rotational motion by an S-type flexible beam system to realize the gripping motion. Combined with the four-arm structure, the manipulating range is expanded. The bonding of the silicon and glass is used to realize the electrical isolation of the gripping arms. At the voltage of 80V, a deflection of the arm tip is 25靘 and the range of the operation is 30m-130靘. Testing results show that the maximum measurement range of the piezoresistive sensors is better than 1mN and the resolution is better than 3霳, which can be used effectively in the force feedback.Keywords：MEMS microgripper;sidewall piezoresistor;Micromanipulation- 32
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Published：2020-08-12 -
High Resolution Measurement of MEMS Rotation Angle Based on Phase Correlation Method
Abstract：High resolution measurement of rotation Motion was achieved to get characteristic and dynamic parameters of MEMS resonator in every moment. The results of measurement gave important reference to improve MEMS performance and reliability. In this paper, for the motion image sequence of microstructures collected by stroboscopic imaging technology, a method based on combination of Radon transform and phase correlation was designed. The motion in Descartes coordinates can be transform to parameters of polar coordinates so that rotation motion is projected to displacement of parameters. The displacement can be measured by phase correlation method to realize subpixel motion measurement. Experimental results achieved that the power of resolution of rotation angle is superior to 0.01°. MEMS motion process is analyzed using the method. The offered solution indicate that the influence of distortion caused by rotation are deceased, and repetition of measurement is increased by always employing the method.Keywords：MEMS resonator;Rotaion angle;Radon transform;phase correlation- 40
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Published：2020-08-12 -
The Application of BP Neural Network on the Multi-position Strap-down North Seeking System
Abstract：In order to fit the sin wave of Strap-down north seeking system and calculate the angle between the start position and the real north accurately, the principle of the system are introduced, and the factors that influence the precision are analyzed. Least square method and back-propagation neural network are adopted separately. Experimental results indicate that the back-propagation neural network is more precision than the least square method, the sum of errors is 0.06, the squared error of errors is 34.45, both of the method get the same average of phases in six measurements, the squared error of BP neural network is 8″, it’s more accurate than the result of the least square method. The back-propagation neural network can satisfy the system precision requirements of curve-fit.Keywords：Strap-down north seeking;curve-fit;back-propagation neural network- 36
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Published：2020-08-12 -
Kinematics analysis of a noval 6-(P-2P-S) parallel macro manipulator
Abstract：A noval 6-(P-2P-S) parallel macro manipulator is put forward, which is used as the macro system of the cutting equipment for chromosome, with the characters of some movement decoupling on the orthogonal posture. Based on the design feature, the position problem and the kinematic transmition performance of the parallel macro manipulator are analyzed. The velocity transmition evaluation indicators is defined. Considering the structure constraints, the distribution of speed transformation evaluation indicators in orientation workspace is analyzed, which can be used as the theoretical foundation of application.Keywords：6-(P-2P-S) parallel macro manipulator;cutting equipment for chromosome;inverse and forward displacement;velocity transmition evaluation indicators;orientation space- 40
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Published：2020-08-12 -
The Basal and Experimental Study of Dispensing Technology of Digitalization of Microfluids
Abstract：Dispensing technology of digitalization of microfluids can control the volume of a droplet precisely per dispensation, using the low viscosity liquids. The coefficient of variation (CV) for diameters of spots is clearly below the measurement error (8%). Different with the existing technologies, dispensing technology of digitalization of microfluids has some special advantages, such as: no heat resource, no movable parts, no pneumatic actuator, and no complicated configuration. The basal experiments are done, using the different low viscosity liquids and driven parameters. Finally, the medium-density microarray is accomplished, and the average diameter of spots is about 100μm.- 60
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Published：2020-08-12 -
One batch type real-time adjusting of drift angle of space camera
Abstract：Real-time adjusting of drift angle could decrease the influence on image quality caused by attitude change and prolong continuous photography time with more TDI integral progression, when space camera was photographing. First, the requirement on Real-time adjusting of drift angle was analyzed in detail and the real-time adjusting tactic was presented. Then the structure of drift angle adjusting system and the operating principle of real-time adjusting were introduced. Finally, a batch type real-time adjusting method was presented and experimented with it. Experimental results indicate that drift angle partial difference can be adjusted below 4.2′, adjusting error is no larger than 72.17″, adjusting time is less than 1s, MTF is 99.67％ on photographing. It totally satisfies the requirement that real-time and long period adjusting of drift angle is no essential influence on image in the process of photographing.Keywords：space camera;Drift angle;Real-time control;image motion compensation;MTF- 40
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Published：2020-08-12 -
A High Performance electromagnetic micro-machined vibrating ring gyroscope
Abstract：Mode matching and high quality factor (Q) are the keys to improve the performance of micro-machined vibrating ring gyroscope. In order to achieve high performance, a novel electromagnetic vibrating ring gyroscope was designed and fabricated, in which the centrosymmetric and enantiomorphous structure consisting of a ring and eight symmetric support springs was adopted to match the resonant frequencies of drive mode and sense mode. The theoretical models for the sensitivity and the mechanical noises of the gyroscope were deduced, moreover the effects of gyroscope parameters to the sensitivity and resolution were analyzed. Through the standard bulk MEMS processes, the gyroscope samples were fabricated with (100) silicon. All the processes are easy to achieve without bonding. Experiments show that the frequency split between the drive and sense modes is smaller than 0.5Hz, and the quality factor is about 500 in atmosphere and 14000 in vacuum with 1Pa. PLA (Phase Locked Amplifier) tests show that the resolution of the gyroscope is 0.05o/s and the sensitivity is 0.2uv/ o/s over a range of -200 ~200 o/s.Keywords：electromagnetic gyroscope;micro-machined gyroscope;vibrating ring- 31
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Published：2020-08-12 -
Design and Fabrication of a DC to 30 GHz DC-Contact Shunt RF MEMS Switch
Abstract：The design and fabrication of DC-contact shunt RF MEMS switch is reported. Au-Au direct contact is achieved by using low stress electroplated Au membrane. Borofloat™ glass is used as substrate. Inside resistance is used to isolate the crosstalk between radio-frequency signal and bias voltage. The distance between the Au membrane and CPW is optimized which make the switch low insertion loss. The contact resistance is 0.1 Ω under the pull-down voltage of 60 V. The insertion loss is -0.03 dB@1 GH, -0.13 dB@10 GHz, -0.19 dB@20 GHz, and in the frequency range from DC to 30 GHz, the insertion loss is less than -0.5 dB; the isolation is -47 dB@1 GHz, -30 dB@10 GHz and -25 dB@20 GHz, and the isolation is better than -23 dB in the frequency range from DC to 30 GHz. The fabricated RF MEMS switch is suitable for the application of frequency range from DC to 30 GHz.Keywords：MEMs;RF MEMS switch;DC-contact shunt- 37
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Published：2020-08-12 -
Hybrid-type MEMS microgripper
Abstract：This work is focused on design and fabrication of a hybrid-type electrostatic silicon microgripper integrated vacuum tool. Vacuum tools are integrated in this novel microgripper in order to improve its pick and place capability. Bulk micromachining technology is employed to fabricate the microgripper from single crystal silicon wafer. The gas circuit controlling and electrical subsystems are designed for the microgripper controlling. At a driving voltage of 80V, a deflection of 25μm at the arm tip of the gripper is achieved. Two different dimensions of the grippers are designed. One gripper is able to pick and place objects of a size ranging from 100μm to 150μm and the other is able to operate objects ranging from 150μm to 200μm.The objects ranging from 100μm to 200μm are picked and placed successfully in the experiment, the experiment indicate that this microgripper can realize the steady manipulation.Keywords：Micromanipulation;microgripper;electrostatic comb drive;vacuum tool- 44
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Published：2020-08-12 -
Study on DSP-based Image Motion Speed Calculation of the Space Camera
Abstract：In order to match image motion at focal plane produced by ground objects movement accurately, the image motion speed calculation method is realized, whose input parameters is the spacecraft location vector and velocity vector based on the WGS-84 coordinate system and spacecraft attitude angle and attitude angular velocity based on spacecraft orbital coordinate system. First of all, the inertial coordinate system is selected flexibly based on the original image motion speed calculation model, so the complexity of solving orbital inclined angel and descending node longitude is decreased. And the cosine value of central angel between spacecraft and descending node is solved by using cosine theorem of spherical Geometry, the cumbersome process of solving central angel cosine value between spacecraft and descending node is avoided by judging the flight direction of satellites and the latitude of sub-satellite point in original motion speed calculation model. Subsequently, the longitude and latitude of sub-satellite point and FLASH address are linked organically and skillfully, the cumbersome lookup process is avoided when elevation data is visited. Then the feasibility of image motion speed calculation model is evaluated by analyzing the impact of image motion speed residual on the camera MTF. Finally, the whole process which calculates the motion speed is realized on DSP from TI. Analyzing and experimental results indicate that the image motion speed calculation residual is 1.5‰, which result in a 1% decrease of the MTF. The time that is cost by Image motion speed calculation is less than 2ms. It can satisfy the system requirements of the camera on the calculation accuracy and computing time.Keywords：Image motion speed;MTF;DEM;WGS-84;DSP- 26
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Published：2020-08-12 -
Camera intrinsic and extrinsic parameters calibration based on rigid ball bar with free motion
Abstract：In this paper a novel approach of calibrating the intrinsic and extrinsic parameters of binocular is proposed. It is based on surveying a rigid ball bar carrying three markers on its middle and extremities moved inside the working volume and it does not require other complex calibration equipment. Firstly, the principal point is assumed at a certain location around the image plane center. the fundamental matrix is found out by Hartley’s eight-point-algorithm. the semi-calibrated fundamental matrix is solved and decomposed by singular-value-decomposition method, and then the focal length is obtained linearly. Secondly, the essential matrix is educed and decomposed by singular-value-decomposition method, then the rotation matrix and translation vector with scale factor are obtained. Thirdly, the coordinates and the distance of the ball bar are solved by triangulation method, and then the scale factor is found out through the true distance of the ball bar. Finally, the estimation of intrinsic and extrinsic parameters of binocular is formulated as a nonlinear minimization problem of a cost function. By using the improved simulated annealing evolutionary strategy algorithm the optimal principal points of two cameras are found out iteratively, and then all parameters of cameras are optimized. In comparison with traditional methods, the novel approach can find out the intrinsic and extrinsic parameters all together, and need not constrain the movement of the one-dimensional object--ball bar. The improved simulated annealing evolutionary strategy algorithm mends and accelerates the global convergence performance.Keywords：camera calibration;ball bar;free motion;semi-calibrated fundamental matrix;simulated annealing evolutionary strategy- 72
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Published：2020-08-12 -
Mechanism of in-band transmission loss in single layer bandpass FSSs
Abstract：The essence of in-band transmission loss of plane wave in infinite planar single layer frequency selective surfaces(FSSs) was illustrated with the distinctions of mismatch transmission loss and dielectric loss. The effects of some parameters on loss characteristics were studied based on modal analysis approach. The loss is high when FSS is illuminated with TE polarization and large incidence angle. The array parameters and aperture width affect the dielectric loss, which always runs in the reverse tendency with bandwidth. Whether the in-band transmission loss of one side dielectric loading is induced mainly by dielectric loss or by in-band reflection depends on the dielectric thickness, but the in-band reflection of FSS with dielectric superstratum is less than substrate. The loss of both sides symmetric loading is due to dielectric loss, which is lower than that of one side loading.Keywords：frequency selective surfaces(FSS);transmission properties;dielectric loss;dielectric loading- 38
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Published：2020-08-12 -
The test design of shape controlled with single electrode Electrostatic about the membrane mirror
Abstract：The membrane mirror stretched with electrostatic is the new technique developed in recent years, and membrane mirror is very light , good flexibility and Collapsible, it will be used widely in space. membrane mirror was sharped by coulomb force in field of electrostatic, which radius is decided by the distributing of electrostatic field. It is very complexity of membrane transfiguration force and the electrostatic field theory ,so there is much work to do about the control theory and technique on membrane mirror. Based on the Research of shaping Stretched Membrane with Electrostatic Curvature Mirrors, the support structure of membrane mirror and control circuit were designed , and the focus was measured by knife-edge. The result is membrane mirror was stretched in 10000V high voltage and it’s focus is about 2.1m, the PV value is 11.14λ, the RMS value is 11.14λ. The following work will be improving the holding structure and using better performance membrane in order to get better surface precision.Keywords：membrane mirror;controlled with single electrode;stretched with electrostatic- 40
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Published：2020-08-12 -
Fabrication of Flexible Hot Film Sensors Arrary and its Optimization
Abstract：Hot film sensors array with nickel as sensing material fabricated on a flexible substrate has been developed, which is flexible and can be attached upon curved surface, such as airfoil’ surface, for rapid distribution measurement of temperature or flow parameters with minimal invasion. The influence of magnetron sputtering and heat treatment parameters, including argon pressure, substrate temperature, sputtering power, and annealing temperature, on sensor’s temperature coefficient of resistance (TCR) has been studied for first time. Finally, high TCR of 4640ppm/℃ with good linearity has been obtained.Keywords：nickel;flexible hot film;sensors array;temperature coefficient of resistance;microfabrication- 36
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Published：2020-08-12 -
Flight parameter computing platform under wind field environments
Abstract：Flight parameter computing platform is the most important supporting technologies of the aircraft development process. This computing platform can be used for validating the design of subsystem and also it can provide the necessary data for the aircraft design. Wind is a key influencing factor of flight parameter. In order to accurately simulate the wind model and calculate the flight parameters, a simulation modeling method for flight parameter simulation platform under wind field environment is established. First, based on the several influence factors of the flight, some mathematical models of the flight parameter simulation platform is established. Second, it modeled on the Simulink toolbox in the Matlab which is based on the principles of hierarchy and modularity and using C MEX S-function for the complex kinetic equations. Then after the models are established, encapsulating this models for several subsystem and assemble them for the flight parameter computing platform based on the unified interface. The simulated tests (including the performance test of a certain gliding aircraft, the wind influence test of a certain uncontrolled aircraft) prove computing capability of the platform, and its calculating step can reach 1 ms. Through comparing with simulation and field test data of a certain uncontrolled aircraft, it shows that the relative deviation of range is 0.44% ，the relative deviation of maximal altitude is 1.8%. Taking QJ 1997-90 as a reference standard, it is demonstrated the platform is rationality and reliable, meets the engineering accuracy requirements.Keywords：Computing platform;Simulink;Flight parameter;Wind model- 36
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Published：2020-08-12 -
Study on device level vacuum packaging technologies of silicon microgyroscopes
Abstract：The high vacuum level and vacuum maintenance of device-level Vacuum packaging for silicon microgyroscopes are studied in order to increase the quality factor and its stability. First, the relationship between error signals and quality factor is analysed based on the dynamics equations of silicon microgyroscopes. The air damping of gyroscopes with high quality factor is analysed using rarefied gas dynamics theory. According the early continual test results of quality factor of vacuum packaged gyroscope, the reasons of vacuum level degrade are given. Temperature programmed desorption-mass spectrometry (TPD-MS) is used to measure the contents of the evolution gases for the ceramic packages and the lid. According to the contents of trapped gases, the reasonable getter is chosen to absorb the gases and keep the vacuum level of the cavity. Finally, the device-level vacuum packaging process is improved. The test results show that the quality factor of gyroscope packaged with new device-level vacuum packaging process is about 162660, which is about fourteen times of quality factor of previous vacuum packaged silicon microgyroscopes, and the change of quality factor is less than 0.05% within one year.Keywords：vacuum packaging;Vacuum maintenance;Getter;Silicon microgyroscopes- 77
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Published：2020-08-12 -
Research on disturbance isolation index and its test method of seeker servo system
Abstract：Angular disturbance isolation is a important function of seeker. The disturbance isolation performance of seeker is often evaluated by isolation index. The principle of disturbance isolation of seeker is analyzed, and the model of isolation index is deduced. By analyzing the structure of stabilization loop of seeker, a isolation index test method based on the dSPACE hardware-in-the-loop simulation system is proposed, which adapt to the stage of controller adjusting. According to add disturbance signal in the stabilization loop using this method, the isolation index is fast tested without simulating missile disturbance by the flight simulation turntable. Compared to the traditional method, this method has simple structure and fast test velocity. Using this method, the isolation index of stabilization loop of a infrared imaging seeker is tested, the results close to the results obtained by using traditional method. It indicates that this method is feasible to test isolation index of seeker or another optoelectronic platform on moving vehicle.Keywords：disturbance isolation;isolation index;dSPACE;seeker- 46
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Published：2020-08-12 -
Research on the Color-difference Detection Algorithm of the Image with Random Texture
Abstract：In order to solve the problem that detecting color-difference of the image with random texture in the actual production environment, based on the research and analysis results both at home and abroad, a color-difference detection algorithm based on the CIELAB color space is proposed in this paper. The algorithm is described in this paper. First, the number of cluster is calculated in the HSV color space. Then the initial cluster center is determined in the CIELAB color space. Finally, the color-difference is detected with fuzzy C-Means clustering. Take the pebble tiles for an example, some experiments in the environment of light, dust and vibration are done in this paper. The experimental results show that color-difference detection algorithm is consistent to the human eye and has anti-interference capability. The test result of color-difference detection algorithm isn’t affected by the dust and vibration interference. The color-difference value is less than 1.5. It is affected by the light interference. The color-difference value is greater than 1.5. So the stability of light power should be reasonable control in the practical application. The algorithm can be used to detect surface color of other random texture.Keywords：feature extract;color space;Color-difference detection- 40
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Published：2020-08-12 -
Hyperspectral Image Anomaly Detection Algorithm Based on Local Orthogonal Subspace Projection
Abstract：The orthogonal subspace projection (OSP) is a supervised classification method, which needs the information of the objects to be classified. To broaden its application fields, we propose the local orthogonal subspace projector (LOSP) and apply it in the anomaly detection of the hyperspectral image. The anomaly detection algorithms find the isolated man-made objects in the nature background, and the kind of the substances in the small local region is usually uniform. Based on the principle, the local projector is constructed through using the detected pixel as the interested object and the mean of its nearby pixels as the object to be suppressed. The experiments show that LOSP can detect the sub-pixel target whose content is greater than 30%, and the target that occupies more pixels can be detected by enlarging the size of the local region. It has been also been tested that LOSP is not affected by the Hughes phenomenon and it costs less than 10% of the RX algorithm when the image has 80 channels. LOSP is effective in both the precision and efficiency, and is applicable to the real-time detection of the hyperspectral image.- 47
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Published：2020-08-12 -
Design of Self-Check Figures Based on Linear CCD Imaging System
Abstract：To proof reliability of the complicated CCD imaging system and to debug it easily, self-check figures are indispensable as image data simulation source. These figures should have the characteristic of push-scan similar to linear CCD, and have variety in gray in column and row direction. As one of numerous figures, this paper elaborates on the distinguishing figure's design procedure, implement and significance. This design was implemented with VHDL language programming based FPGA. The author applied TEXTIO function to export figure data to a text through gate-level simulation with Modesim, then imported the text and showed the expected figure in MATLAB. These figures have been applied and proved out in a CCD imaging system.Keywords：Self-check figure;Linear CCD;Distinguishing figure;TEXTIO;MATLAB- 37
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Published：2020-08-12 -
Research on Properties and Application Technology of CMOS Image Sensor with Rolling Shutter
Abstract：In order to research the specific applications of CMOS image sensor rolling shutter ,this paper research with specific CMOS image sensor. First, this paper introduces the principle and characteristics of global shutter and rolling shutter of the CMOS imager, it analyzes the impact of rolling shutter on measurement precision of the imaging system based on CMOS imager .Imaging experiment is taken to test the analyses of the rolling shutter. Then, an original method for computing instantaneous 3D pose and velocity of fast moving objects using a single view is presented. It exploits image deformations induced by rolling shutter in CMOS image sensors. Finally, a general perspective projection model of a moving 3D point is presented. A solution for the pose and velocity recovery problem is then described. Results indicate that some aberrations appears in faith, and the aberration degree has close relations with some parameters of CMOS imager like integration. After experiments can minimize error in the case of moving objects by the pose and speed parameters, the calculation error is under 2.5 percent. Experimental results with real data confirm the relevance of the approach. The resulting algorithm enables to transform a CMOS low cost and low power camera into an original velocity sensor.Keywords：CMOS Imager Rolling Shutter Calibration of Camera- 47
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Published：2020-08-12 -
A New Method of Feature-level Fusion Recognition Based on Complex-valued Independent Component Analysis (ICA)
Abstract：Abstract: In our paper, we introduce the basic principle and algorithm of the Complex Valued ICA, and a new target recognition algorithm based on Complex Valued ICA is proposed. With our method, we must compose complex value training group matrix with two images from different cameras, secondly, the Fast ICA algorithm is performed on the matrix to get independent components (ICs), in the third step, we need extract the training set and testing set’s features based on ICs, then Fisher discriminant analysis is introduced to train target features’ pattern, at last, the classification of targets in testing set is performed. Our experimental data show that the method proposed in our paper is feasible and the target recognition rate is satisfied.Keywords：complex ICA;target recognition;multi-sensor image fusion;feature-level fusion- 59
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Published：2020-08-12 -
IR Small Targets Recognition in sky background Based on the Information Fusion
Abstract：In allusion to the difficulty of recognizing IR small targets in sky background and the lowness of recognition reliabilities, a new improved method of small targets recognition is proposed based on the previous methods. The information of the targets’ velocity and gray is regarded as the major basis of recognition, while the information of track of the targets is regarded as the additional basis. When the targets can not be recognized by only using the information of targets’ velocity and the gray, the information of targets’ tracks is added to the evidences to fuse using the unfair D-S evidence information fusion method. Simulation results show that recognition reliabilities are raised to previous 125% without adding new sensor.Keywords：Small target recognition;information fusion;D-S evidential theory- 39
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Published：2020-08-12 -
Iris Recognition Based on Zero-crossing Position of Wavelet Transform and Matching Using Variable-length Code
Abstract：Changing the variable-length code to equal-length code is required in feature match process of conventional algorithm based on the zero-crossing of the wavelet transform first proposed by Boles. But the factor for the variability of the code length is complex, so through the process of compulsively changing the variable-length code to equal-length code, the final recognition rate will be influenced. Aiming at the above problem, an iris recognition algorithm based on zero-crossing position of wavelet transform and matching using variable-length code is proposed. After the zero-crossing positions of the wavelet transform at each level from the 4th decompose level to the 8th decompose level are calculated, a sort of shift-matching algorithm is used to directly calculate the distance of the variable-length code, the detailed process is that, the distance of the two samples is calculated at each relative shift has occurred, then the minimal distance is chosen as the distance of the two sample. In iris database containing 800 images, experimental results show that the recognition rate of this method reaches 97.70％, about 5.16％ higher than that of Boles’ method, while the feature extracting time and the match time is only 0.2s. It can satisfy the system requirements of the capability of real time in iris recognition system.Keywords：biometrics;iris recognition;wavelet transform;zero-crossing;variable-length code- 25
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Published：2020-08-12 -
A Grade-based Unequal Clustering Algorithm for wireless sensor networks
Abstract：To deal with the ‘hot spot’ problem of ‘many-to-one’ traffic pattern in data gathering wireless sensor network, an grafe-based unequal clustering algorithm is proposed. First, based on the analysis of the data gathering traffic model, given the relationship between the hops to sink with the load of CHs. After that, we presents a grade-based load-balancing clustering algorithm for wireless sensor network, in which cluster size are based on node’s grade, cluster head selection using mulit-weight. Simulation results show that the stand deviation of CHs’ load with different grade are reduced 9 times. The algorithm effectively balances the load of CHs.- 49
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Published：2020-08-12 -
Fast classification of benign and malignant solitary pulmonary nodules in CT image
Abstract：Objective: In order to break through the bottleneck of low accuracy diagnosis with medical signs in medical imaging diagnostics, effective image features of solitary pulmonary nodules (SPN) need to be found for the computer-aided diagnosis system quickly and accurately differentiating benign and malignant SPNs in chest CT images. Method: First, SPNs are extracted from chest CT images using interactive segmentation. Second, the multi-resolution histograms of SPNs are directly calculated to receive a high-dimensional features sample set with spatial information of SPNs.Then the classifier for differentiating benign and malignant SPN is constructed with making full use the advantage of SVM which is good at dealing with high dimensional data sets. Finally, the performance of classification is evaluated by testing the trained SVM with the test sample set. Result: The test results by 214 cases show that it takes 4.83s for computing 768 dimensional features of 240 SPNs, 2.24s for training and testing the SVM classifier. Receiver Operating Characteristic (ROC) analysis of classification performance of the proposed approach shows that the sensitivity is 73.33%,specificity is 70%,accuracy is 71.67%,and the Area Under Curve (AUC) is nearly 0.7864. Conclusion: Image spatial information can effectively express the characteristics of SPN, the system classification accuracy of benign and malignant SPNs is up to 71.67% without medical signs, and the classification velocity is about 50 times than traditional texture methods. It provides a feasible, simple, objective method for solving the problem in medical imaging diagnosis of the SPN.Keywords：Solitary Pulmonary Nodule;CT Image;Benign and Malignant;multi-resolution histogram;Support Vector Machine- 27
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Published：2020-08-12 -
Study the effect on tip shape by changing mask direction
Abstract：The effect on tip shape by changing the mask direction is studied, in order to fabricate high aspect ratio nano-silicon-tips. This paper presents the fabrication processes for nano-silicon-tips using an (100) single crystal silicon wafer. The evolution of higher order {411} crystal planes during corner undercutting in anisotropic etching of (100) silicon and the effect on tip shape by the factor of mask direction are discussed, by experiment and the model of {411} crystal planes. Experimental results indicate that the profiles of silicon tip are constituted by {411} crystal planes at 76.37°and silicon tips of octahedron and tetrahedron are fabricated with changing mask directions. Nano-silicon-tips are formed by anisotropic etching in 40% KOH etchant at 78 ℃ and oxidation sharpening technique, high aspect ratio of the tips is greater than 2, as the square masks aligning to <110> direction.Keywords：silicon tip;anisotropic;oxidation sharpening;mask- 52
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Published：2020-08-12
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