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Issue 4 ， 2018
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Fabrication and testing of large aspheric system based on common reference
Abstract：A key technology for fabricating and testing three mirror astigmatism (TMA) was proposed based on a common reference, to overcome the difficulty of manufacturing and aligning large off-axis aspheric systems. The analysis and research of the basic principles involved were presented. When the Root Mean Square (RMS) of the surface error of the primary mirror and tertiary mirrors was better than λ/10 (for wavelength λ at 632.8 nm), the primary and tertiary mirrors were measured and aligned with the common reference and the same supporting back plate, with the two mirrors were then being polished by Ion Beam Figuring (IBF). A large TMA system with primary and tertiary mirror apertures of 724 mm×247 mm and 632 mm×205 mm, respectively was fabricated and tested based on the proposed method. The integrated mirrors were polished by IBF, and the RMSs of the surface error of the primary and tertiary mirrors are 0.019λ and 0.017λ, respectively.Keywords：optical fabrication;optical testing;aspheric surface;Three Mirror Astigmatism(TMA);common reference;Ion Beam Figuring(IBF)- 82
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Published：2020-07-05 -
Influence of polarization prism extinction ratio in rapid space angle measuring system
Abstract：In order to enable a rapid space angle measuring system to realize the required measurement function in a certain translation range, we have investigated the system angle error caused by the nonuniform distribution of the extinction ratio of an incident and azimuth beam after passing through a Glan-Taylor prism. First, the system coordinate model was established. The ray tracing method and Jones matrix description of polarized light were used to deduce the angle error caused by the extinction ratio of the G Keywords：polarization measurement;polarized light;azimuth measurement;extinction rate;Glan-Taylor prism- 72
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Published：2020-07-05 -
Optimal layout of calibration target in terrestrial laser scanning
Abstract：Deformation monitoring with terrestrial 3D laser scanner commonly uses fixed calibration targets to register point cloud data of multiple periods. Therefore, the accuracy of the target registration directly affects the measurement error. In order to improve registration accuracy, measurement errors of different calibration target layout were analyzed. First, the calibration target points (M1-M8) at different distances (25, 50, 100, 150, 200 m) are registered, and the differences in the coordinates of eight Keywords：Terrestrial Laser Scanning(TLS);calibration target;deformation monitoring;error analysis;target registration- 73
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Published：2020-07-05 -
In situ measurement of phytoplankton size class
Abstract：Size-fractionated filtration is a common approach for measuring phytoplankton size classes in marine observation. However, this approach is time-consuming and unsuitable for analysis of a large number of samples in profiling measurement. In this paper, an in situ measurement system was developed for retrieving the phytoplankton size classes using light absorption coefficient of seawater. The hardware system of this instrument consists of a light system, optical windows, sample cell, fiber optic cable, mini- Keywords：phytoplankton size class;in situ measurement;light absorption of seawater;spectral analysis- 70
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Published：2020-07-05 -
Ritchey-Common interferometry using unit-excitation influence matrix's numerical calculation method
Abstract：Calculating the influence matrix between surface error and wavefront aberration is a key step in the Ritchey-Common test. A method that uses unit-excitation operation to calculate the influence matrix with high accuracy was studied in order to improve the precision of the test. It retrieves the system wavefront aberration when the flat mirror concludes only one kind of Zernike aberration, and obtains the influence coefficient vector through Zernike fitting. The influence matrix is formed from the coefficien Keywords：optical inspection;unit-excitation method;numerical calculation;Ritchey-Common method;Zernike fitting- 71
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Published：2020-07-05 -
Optical target recognition based on optical path of Mach-Zehnder interferometric
Abstract：A new method has been proposed to improve the detection and recognition of optical targets using a laser active detection system. The proposed method uses the scanning interference field to transform the spatial distribution of the target into the time distribution of the detected light, and uses the characteristics of the time distribution of the reflected light for identifying optical targets in a complex background. Expressions giving the optical path difference of coherent beams at any point in the far- Keywords：laser active detection;coherent detection;Mach-Zehnder interferometer;optical target;diffuse reflection- 98
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Published：2020-07-05 -
Design and construction of real-time all-polarization imaging detector for skylight
Abstract：Researchers have been highly inspired by the bio-use of polarized light navigation, and increasing number of studies are being conducted at the same time. A precise sky polarization field map is one of the prerequisites for polarization navigation and many imaging polarization detectors have thus been developed for attaining a more accurate sky polarization field map. This study proposes a novel real-time all-polarization imaging detector that can obtain all the parameters of the Stokes vector, and can ther Keywords：polarization imaging detection;polarization navigation;sky polarization field map;image processing- 75
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Published：2020-07-05 -
High-sensitivty detection of space targets at close range
Abstract：In order to achieve high sensitivity space target imaging under the condition of close distance, the inertial space tracking and pointing model, terminal sliding mode control method which stabilize the image, imaging frequency independent matching technology were designed to achieve space target stable pointed and high signal-to-noise ratio imaging by high sensitivity CMOS camera. Finally, satellite three axis attitude control simulation system, space-based LED target display system and high sensitivity CMO Keywords：space surveillance;space target;high sensitivity;low illuminance;intelligent matching;Signal Noise to Ratio(SNR)- 100
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Published：2020-07-05 -
A objective function with measuring error uncertainty weighted for pose estimation in stereo vision
Abstract：In order to investigate the effect of anisotropic and correlated non-identical gray distributions of feature points on pose estimation, a novel objective function with error uncertainty weighted of feature points was proposed. In the method, the inverse covariance matrix was utilized to describe the directional uncertainty of feature points, and weighted contribution of uncertainty to the error objective function was analysed. By transforming the uncertainty into a covariance-weighted data space, the novel Keywords：stereo-vision;uncertainty;weighted measuring error;objective function;pose estimation- 91
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Published：2020-07-05
Modern Applied Optics
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Measurement of thoraco-abdominal surface using 3D Fourier transform
Abstract：This paper proposes a 3D Fourier transform measurement method for thoraco-abdominal surface. It has important applications in the 3D measurement of the motion of human thoraco-abdominal surface for accurate radiotherapy in the medical field. The method combines 3D Fourier fringe analysis (3D-FFA) with triple-frequency temporal phase unwrapping. It uses three primary colors that include three cosine fringe patterns with different frequencies to generate a composite pattern, and can achieve the corresponding Keywords：3D Fourier transform;wrapped phase;gaussian filter;temporal phase unwrapping;thoraco-abdominal surface- 87
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Published：2020-07-05 -
Effectiveness verification of attitude compensation for airborne LiDAR
Abstract：Airborne LiDAR scans a terrain surface to obtain a laser point cloud, which is used to reconstruct a 3-D image of the surveyed terrain. During the measurement procedure of airborne LiDAR, the attitude angles of the airborne platform always fluctuate, which has a significant influence on the point density distribution of the laser point cloud and on the accuracy of the reconstructed digital surface model (DSM). In order to compensate for the adverse effects of attitude fluctuations, an attitude compensation Keywords：airborne LiDAR;attitude fluctuation;point density;semi-physical simulation;compensation;digital surface model accuracy;point cloud- 99
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Published：2020-07-05 -
Estimation of albedo coefficient of Earth during LEO satellite falling
Abstract：In order to estimate the albedo coefficient of the Earth, one needs to investigate the change in solar array output current of a low Earth orbit (LEO) satellite caused by the sunlight reflected from the Earth while the satellite is falling to the ground. An LEO satellite orbiting along a sun-synchronous orbit at an altitude of 300 km with a local time of descending node (LTDN) of 10:30 A.M. is selected as the sample. Details of the semi-major axis degradation, inclination perturbance, solar incidence variat Keywords：low earth orbit satellite;earth albedo;least square estimation;solar array current;satellite telemetry- 73
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Published：2020-07-05
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Effect of ethanol solution on self-condition property of hydrophilic fixed abrasive pad
Abstract：Self-condition property is one of the most important parameters to evaluate the processing performance of hydrophilic fixed abrasive pad. In this paper, the ethanol solution with different concentrations was selected as the abrasive media, and the swelling rate and slurry wear rate were developed to characterize the property of the matrix for hydrophilic fixed abrasive pad. The processing properties were described with the quartz glass lapping experiment with those slurries. Material Removal Rate Variation( Keywords：lapping;ethanol solution;Material Removal Rate Variation(MRRV);hydrophilic fixed abrasive pad;self-conditioning- 73
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Published：2020-07-05 -
Integrated system of azimuth structure for extremely large telescopes
Abstract：In order to reconcile large deformations of the azimuth structure for the Extremely Large Telescope(ELT), an innovative mechanism based on hydrostatic bearings and linear drives was established and it combined both the bearing and drive functions. Placed motors close to hydrostatic bearings allowed a fairly constant air-gap to be maintained despite the dimensions of the structure. This allowed the motor to be designed with a relative small air-gap and consequently higher efficiency for a defined motor dimen Keywords：extremely large telescope;mechanism;hydrostatic bearings;linear motors;kinematical joint;ANSYS simulation- 66
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Published：2020-07-05 -
Experimental research on high-efficiency electrochemical machining of multi-stepped cylindrical microelectrode with high rotating precision
Abstract：In order to achieve the high-efficiency machining of multi-stepped cylindrical microelectrode with high rotating precision, the electrochemical etching process of multi-stepped electrode was studied and improved deeply. Firstly, according to the principle of electrochemical etching, the effect of machining current on the change of electrode diameter was deduced. Secondly, the experiments proved that the electrode rotation could improve the current change rate and the effective initial current and thus impro Keywords：multi-stepped cylindrical microelectrode;machining efficiency;rotating precision;electrode rotation;machining current- 82
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Published：2020-07-05 -
Electrocooling technology based on surface discharge of thin coplanar flat electrodes
Abstract：The DC surface high voltage discharge of thin coplanar flat electrodes was experimentally analyzed for the purpose of studying a cooling technology in radar filed. A series of samples including two symmetrical cathodes and one anode with a sharp tip were built to evaluate the effects on surface discharge of the separation between two thin coplanar flat electrodes and the flow resistance between ions and a flat substrate. A series of tests have been done for the surface discharge characteristics by changing Keywords：surface discharge;thin coplanar flat electrode;electrocooling;surface electrohydrodynamic;radar technology- 73
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Published：2020-07-05 -
A capacitive liquid level sensor interface application specitic integrated circuit for new carrier rocket
Abstract：In order to improve the capacitance detection performance of capacitive liquid level sensor in new aerospace carrier rocket, an interface (Application Specitic Integrated Circuit)ASIC of capacitive liquid level sensor in aerospace carrier rocket was designed. First, the system of the whole circuit was designed, which converted the output capacitance of capacitive liquid level sensor to voltage that had linear relationship with the output capacitance of the sensor. And then, the linearity, noise characterist Keywords：capacitive liquid level sensor;weak-capacitance detection;interface Application Specitic Integrated Circuit(ASIC);switched-capacitor circuits- 66
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Published：2020-07-05 -
Influences of local reinforcements on the snap-through characteristics of pre-compressed bistable structures
Abstract：For the bistable structures formed through compressing the strait beams into post-buckling modes, their bistable characteristics such as snap-through/maintain forces and snap-through distance are deeply related to the pre-stress distribution and the buckling mode. Thus, it is difficult to achieve a required specific bistable characteristic through only adjusting the pre-stress load. For this reason, one effective method was proposed for adjusting the critical buckling load and snap-through characteristics b Keywords：bistable structures;snap-through force;local reinforcement;pre-stress;adjustability- 106
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Published：2020-07-05 -
Wafer-level composite mold for large-area nanoimprint lithography
Abstract：In order to solve the problem of producing large-size and wafer-level composite flexible mold at low cost and high throughput for the large area NIL, this paper systematically investigated the theoretical model, numerical simulation and fabrication method for a large-size and wafer-level composite flexible mold with double-layer structures. Two models regarding the peel off demolding and the air bubble defects generated were proposed. Furthermore, the influence factors and laws of the peel demolding paramet Keywords：large area nanoimprint lithographt;composite flexible mold;anti-adhesion;peel off demolding;wafer-level- 84
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Published：2020-07-05
Micro/Nano Technology and Fine Mechanics
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Singular optimal control for three-axis reorientation of an agile satellite
Abstract：The possibility of singular optimal control in the time-optimal reorientation of an agile satellite with independent three-axis control was investigated in this paper. Generally, it is assumed that the switching functions take the value zero only at isolated points, which dictates that the controls are "bang-bang". However, some new results were found in this paper. An inertially symmetric rigid body was considered. Based on the optimum model, two propositions about the switching functions were derived. All Keywords：rigid spacecraft;agile satellite;timeoptimal;reorientation;singular optimal control- 73
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Published：2020-07-05 -
No-reference image quality assessment using joint color space statistical and texture feature
Abstract：In order to evaluate the image quality objectively, a no-reference image quality evaluation model, which combined color space statistical feature and weighted local binary model (LBP) texture features, was established in this paper. Firstly, the mean subtracted contrast normalized (MSCN) coefficients were obtained by applying MSCN to the luminance of the distorted image. Then, the statistical parameters and weighted LBP histogram features were extracted from the MSCN coefficients. The statistical parameters Keywords：no-referenceimage quality assessment;Mean Subtracted Contrast Normalized(MSCN) coefficients statistics;color components;weighted Local Binary Pattern(LBP) histogram- 92
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Published：2020-07-05 -
A small scale wind shear detection algorithm of modified F-factor for wind-profiling lidar
Abstract：Aiming at the problem that a small but strong clear sky wind shear induced by the complex terrain or geographical environment and other factors cannot be detected by the existing wind shear detection algorithm, a small scale wind shear detection algorithm of lidar's modified F factor was put forward. The vertical wind speed component that could not be directly measured by lidar in traditional F-factor was converted into radial wind speed gradient by theoretical model, thus the key point for solving the F-fa Keywords：radial wind speed gradient;small scale wind shear;glide-path scanning;lidar- 75
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Published：2020-07-05 -
Denoising of DSPI phase map using sine-cosine filtering and signal energy
Abstract：The speckle noise in digital speckle pattern interferometry (DSPI) results in difficulty in phase extraction and decreases measurement sensitivity. A denoising method using sine-cosine filtering and signal energy was proposed to smooth phase maps of DSPI. It exceeded traditional sine-cosine denoising method in adaptively and phase map quality. In the method, noise energy of DSPI phase map was estimated by energy of orthogonal wavelet packet. The phase map was transformed by sine-cosine method and was smooth Keywords：Digital Speckle Pattern Interferometry(DSPI);phase map;sine-cosine filtering;noise energy- 75
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Published：2020-07-05 -
HDR imaging method of overcoming full well limitation for push-broom remote sensing cameras
Abstract：In order to increase the dynamic range of push-broom remote sensing cameras, An imaging method which applied the DTDI (Digital domain Time Delay Integration) technology with fixed integral stages and display method of HDR (High Dynamic Range) image was investigated in this paper. Firstly, the principle of DTDI was introduced. Secondly, by adopting the DTDI technology with fixed integral stage, the full well limitation could be overcome. Thus, a picture with higher image bit depth and larger dynamic range co Keywords：Complementary Metal Oxide Semiconductor(CMOS);Digital domain Time Delay Integration(DTDI);overcome the limit of full well;push-broom remote sensing cameras- 72
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Published：2020-07-05 -
Deep convolutional autoencoder networks approach to low-light level image restoration under extreme low-light illumination
Abstract：LLL (Low-Light Level)/infrared image color fusion is an important development direction of night vision technology in the world. Under extreme low light level (environment illumination less than), LLL image has low signal to noise ratio and low contrast features, and the target is difficult to identify as imaging device limitations, which has been a key constraint to color night vision technology. In order to improve target detection and recognition rate, LLL image restoration method based on the deep convo Keywords：Low-Light-Level image(LLL);image restoration;convolutional neural network;image de-noise;sub-pixel convolution- 73
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Published：2020-07-05 -
Automated image segmentation based on pulse coupled neural network with partide swarm optimization and comprehensive evaluation
Abstract：Multi-parameter setting and single segmentation evaluation criterion are the problems in image segmentation based on Pulse Coupled Neural Network (PCNN). Through combining Particle Swarm Optimization (PSO) with comprehensive evaluation criterion, this paper presented an automatic image segmentation algorithm based on PCNN. The improved PCNN model with monotonically increasing threshold search strategy was utilized in this algorithm. The Comprehensive Evaluation Criterion(CEC) obtained by cross-entropy param Keywords：Pulse Coupled Neural Network(PCNN);Particle Swarm Optimization(PSO);comprehensive evaluation;parameter adaptive;image segmentation- 90
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Published：2020-07-05 -
Design and implementation of high speed and reliable transmission platform in fast view system
Abstract：Aiming at the problem of the high data rate of remote sensing satellite cameras and the insufficient transmission bandwidth of fast view system, a new high speed reliable transmission system based on 10 Gb/s Ethernet was proposed and performed. The front end of the transmission system adopted FPGA as the main control unit that constructed the reliable transmission protocol stack. The transmission system achieved the reliable transmission for high speed data stream by ack-resend algorithm and flow control in Keywords：fast view;high speed data transmission;reliable data transmission;FPGA;10 Gb/s Ethernet- 85
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Published：2020-07-05 -
Fusion of multi-scale feature using multiple kernel learning for hyperspectral image land cover classification
Abstract：In order to make full use of the spatial information and spectral information and improve the classification accuracy of hyperspectral imager, a fusion multi-scale feature with multiple kernel learning method was proposed in this paper. Firstly, multi-scale features were extracted by multi-scale spatial filtering and PCA whitening. Then multiple kernels were used to represent the multi-scale feature in the framework of kernel sparse representation classifier. The kernel weight was computed according to the Keywords：hyperspectral image;SRC;multi-scale;multiple kernel learning;land cover classification- 97
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Published：2020-07-05 -
Visual tracking algorithm based on the sparse-regularized subspace
Abstract：Aiming at the problem that the subspace representation tracking algorithm cannot deal with the occlusion problem effectively and the sparse representation tracking algorithm cannot meet the real-time requirements of the tracking, this paper proposed a sparse-regularized subspace visual tracking algorithm. The algorithm combined the advantages of subspace representation and sparse representation, improved the processing ability of the occlusion problem, and reduced the computational complexity. Firstly, the Keywords：sparse representation;visual tracking;subspace representation;particle filter- 97
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Published：2020-07-05 -
An atom scan strategy for OLED micro display
Abstract：An atom scanning system was established in order to improve scanning efficiency and achieve resolution better than 2K for flat-panel displays. The atom scanning strategy was analyzed using mathematical matrices based on fractal geometry. First, the existing PWM scanning strategies were analyzed. Next, we performed a comparative study of the performances of different scanning strategies, and illustrated that the atom scanning method exhibits the best performance. Our experimental results indicate that linearity is preferred when the weight value of 8 bits is converted to 128:64:32:16:9:4:2:1 for 256 level gray-scale images. For a resolution of 1600×1600 with a clock frequency of 50 MHz, the scanning frame frequency reaches 90 Hz, while the linearity and transmission efficiency are 99.8% and 100%, respectively. Thus, the requirements of extremely high resolution and frame frequency, low clock frequency, and high linearity are satisfied.Keywords：Organic Light-Emitting Diode(OLED);microdisplay;ultra-high resolution;fractal scan;atom scan- 89
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Published：2020-07-05
Information Sciences
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