Chinese Version Light学术出版中心
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Issue 2 ， 2019
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Scanning beam splitting and speckle reduction system for laser backlight TV
Abstract：Lasers demonstrate characteristics of high brightness and good monochromaticity. Moreover, the cost of liquid crystal display (LCD) planes are low as they have been developed extensively. Because of their excellent display performance, laser LCD televisions (TVs), which use lasers as their backlight, demonstrate strong market competitiveness and extensive market potential. The use of a light source array is a common technique for backlight system design. To limit the high power supplied by a single laser di Keywords：LC-TV;laser TV;galvanometer scanner;backlight;beam splitting;speckle suppression- 122
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Published：2020-08-13 -
Frequency drift error and its compensation in polarization modulation range-finding system
Abstract：To improve the accuracy of frequency measurement in a polarization modulation range-finding system, a method based on dual-directional frequency sweep was proposed. First, the principle of the ranging method and the relationship between frequency and ranging stability were analyzed. Then, factors influencing frequency drift, as well as the changing law of drift in the system, were discussed, and it was proved that modulation depth and thermally induced additional phase delay are important factors affecting frequency drift. Accordingly, a compensation method was proposed to compensate for the frequency drift caused by additional thermal phase delay, which can be realized with low modulation depth. Experimental results show that, for the target at 15.23 m, the standard deviation of frequency measurement decreased from 3.822 9×10 4 Hz to 5.807 5×103 Hz, the ranging error decreased from 7.513 7 mm to 0.866 7 mm, and the validity of the method was verified.Keywords：measurement;absolute distance measurement;drift error;error compensation- 149
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Published：2020-08-13 -
Application of tapered fibers to free-space optical communication coupling system
Abstract：Free-space optical communication has many advantages over traditional communication. Improving the coupling efficiency of free-space optical communication (FSOC) receivers is of great significance for the quality of communication. We used tapered fibers in optical coupling. Based on the simulation results using the BPM algorithm, tapered fibers with low loss transmission were prepared using a fusion taper method. First, the mode field transmission characteristics of the tapered fibers and double tapered fib Keywords：free-space optical communication;tapered fiber;mode field analysis;coupling efficiency;transmission efficiency- 97
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Published：2020-08-13 -
Location method for principal section orientation of KDP or DKDP frequency-doubling crystal
Abstract：A frequency-doubling crystal is one of the most important light components in the inertial confinement fusion (ICF) facility. The principal section is closely related to the phase-matching angle and the absorption coefficient of the frequency-doubling crystal. To orient the principal section accurately, an indirect measurement method is presented based on light intensity. A measurement system was established using a laser, power stabilizer, half-plate, crystal, polarizer, and analyzer. The position of extin Keywords：frequency-doubling crystal;principal section;jones matrix;the least square fitting- 140
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Published：2020-08-13 -
Polishing method for polyimide membranes based on reactive ion etching
Abstract：To improve the surface quality of polyimide (PI) optics, a polishing method for polyimide membranes based on Reactive Ion Etching (RIE) was proposed. The working principle and experimental research for the proposed method were discussed in this study. Owing to the low surface tension and mobility of the PR fluid, surface defects on the PI surface were required to be filled by a PR coating. In addition, owing to the highly anisotropic and identical RIE rates for PR and PI, the smooth PR surface could be prec Keywords：polishing;polyimide;photoresist;reactive ion etching- 90
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Published：2020-08-13 -
Microstructure and high-temperature oxidation resistance of laser cladding in-situ synthesis Ti-Al-Si composite coatings
Abstract：To improve the high-temperature oxidation resistance of titanium alloys. Two kinds of Ti:Al:Si=41:41:18 (at.%) and Ti:Al:Si=35:35:30 (at.%) composite coatings were fabricated by laser cladding in-situ synthesis on TC4 titanium alloy. The microstructure and phase composition of the composite coatings were characterized by X-ray Diffraction (XRD), Optical Microscopy (OM) and Scanning Electron Microscope (SEM). The oxidation resistance of the coatings and the substrate sample under 800 ℃×24 h×5 times cycle oxi Keywords：laser in-situ synthesis;titanium alloy;composite coating;microstructure;high-temperature oxidation resistance- 92
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Published：2020-08-13 -
On-board vicarious calibration of FY-3C UV total ozone unit
Abstract：Previously, ozone products could not be generated due to the abnormal solar irradiance for a total ozone unit (TOU) on FY-3C, because the instrumental degradation coefficient could not be measured. After investigating the irradiation measurement data and degradation trends of FY-3B/TOU and combining this with FY-3C/TOU radiance and irradiance data, methods for calculating instrumental degradation coefficients were explored based on clear ocean pixel data. An area in the atmosphere above the Pacific Ocean wa Keywords：on-board calibration;Ultra-violet(UV) remote sensing;total ozone amount;FY-3;Total Ozone Unit(TOU);validation- 96
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Published：2020-08-13
Modern Applied Optics
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Location method for principal section orientation of KDP or DKDP frequency-doubling crystal
Abstract：A frequency-doubling crystal is one of the most important light components in the inertial confinement fusion (ICF) facility. The principal section is closely related to the phase-matching angle and the absorption coefficient of the frequency-doubling crystal. To orient the principal section accurately, an indirect measurement method is presented based on light intensity. A measurement system was established using a laser, power stabilizer, half-plate, crystal, polarizer, and analyzer. The position of extinction, which was the principal section of the crystal, was obtained by rotating the polarizer and analyzer simultaneously. The Jones matrix model for the measurement system was deduced, and an expression formula for the relationship between light intensity, polarizer, and analyzer was derived. Through least squares curve fitting, the orientation of the principal section can be found. The validity of the model was verified using the simulation and experimental results. The test data show that the repeatability of orientation was better than 0.02°. The location accuracy of this method satisfies the requirements of KDP or DKDP frequency-doubling crystals in the ICF.Keywords：Frequency doubling crystal;principal section;jones matrix;the least square fitting- 56
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Published：2020-08-13 -
The polishing method for polyimide membrane based on reactive ion etching
Abstract：In order to further improve the surface quality of polyimide (PI) optics, the polishing method based on reactive ion etching (RIE) for polyimide membrane is proposed. The principle and experimental research for the method are discussed. With the low surface tension and mobility of the PR fluid, the surface defect on the PI surface will be filled by coating the PR on. Combined with the high anisotropic and equal etching rate RIE for PR and PI, the smooth surface of PR can be transferred to the PI precisely. Finally, the polishing of PI membrane can be realized. Experimental results indicate that the rough surface with PV and RMS of 1.347μmand 340nmcan be reduced to 75nm and 13nm after double polishing. The surface roughness of 61nmPV and 8nm RMS can be reduced to 9nm and 1nm. The polishing method based on RIE can improve the surface finish of PI membrane efficiently, which can provide a new ideas for the precision manufacturing of polymer flexible devices represented by PI.Keywords：polyimide;polishing;photoresist;reactive ion etching- 55
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Published：2020-08-13 -
Study on Power Failure Compensation Method for Magnetically Suspended TMP based on Average Power Balance Control
Abstract：High-speed magnetically suspended turbo molecular pump (TMP) have been widely used in the industrial-applications for high energy density, micro-vibration, and no lubrication requirements. However, the AMB system will lose magnetic force once the mains power fails, which may cause severe damage to the rotor and stator system. In this paper, an improved power failure compensation control (PFCC) method based on average power balance control (APBC) is proposed. Firstly, a motor energy feedback circuit is designed. Then, a nonlinear controller consisting of double control loops is proposed, of which the fast inner current loop uses sliding mode control (SMC) and outer voltage loop uses the APBC. The Lyapunov function is structured and analyzed to ensure the system stability; Finally, a platform based on high-speed magnetically suspended TMP is built. Several experiment results verify that the proposed PFCC method has fast response and robustness, meanwhile, the touchdown speed of rotor reduced to 3900 r/min from rated speed 21000 r/min with a higher energy conversion efficiency up to 96.6%, which greatly improved the safety of AMB system.Keywords：magnetic bearings;DC/DC converter;motor energy feedback;PFCC- 59
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Published：2020-08-13 -
The Optimization of the Layout of Warping Harness of Segmented-Mirror Telescope
Abstract：In order to reduce the high cost of mirror polishing and opto-mechanical assembly and correct the low-order aberrations caused by thermal and gravity deformation, so called “Warping Harness” has been used to apply moment to the pivot of whiffletree to achieve real-time correction of the mirror surface. This Warping Harness has been adopted in some large astronomical telescopes. This paper is intended to optimize the layout of actuators that may be applied to Chinese large optical telescope in the near future. In this paper, firstly, the correction ability of the Warping Harness is determined according to the actual engineering experience and reference paper. Secondly, the integrated modeling of the segment support assembly is carried out by the 3D drawing software. Finally, the layout of actuators is optimized by the finite element simulation and the least-square method. The results show that the design of 18-actuators can correct the aberration of focus, astigmatism, coma and trefoil well. The design of 18- actuators can not only meet the requirements of optical design, but also have lower cost and high efficiency.Keywords：segmented-mirror;warping harness;finite element method;reduction factor;mirror figuration analysis- 76
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Published：2020-08-13 -
Path planning of free-floating space robot based on control variable parameterization method
Abstract：In view of the problem that the traditional path planning method of free floating space robot has large disturbance to the base seat satellite, a path planning method based on the parameterization of control variables is proposed. The method transforms the path planning problem into an optimal control problem with the minimum of the base posture disturbance as the objective function and a series of constraints. The control variable parameterization method is used to discretize the problem, and the optimal control problem is transformed into a nonlinear programming problem, and a complete theoretical convergence proof is given. Thus, the optimal path of the end effector of the free floating space robot can be accurately estimated. The simulation results show that, compared with the traditional method of decomposition acceleration, the attitude disturbance of the base satellite caused by the motion path of the method is 0.104rad, which is 17.53% lower than the traditional method, which verifies the effectiveness and the optimality of the proposed path planning method.Keywords：space free-floating robot;attitude disturbance;control variable parameterization;path planning- 44
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Published：2020-08-13 -
Design and implementation of combination cam-type Z-pin Pre-insertion device for aeronautical material
Abstract：In this study, a new highefficiency and highprecision Zpin preinsertion based on a combination cam was developed to solve the problems, such as low efficiency, easy breaking, and slipping of Zpin insertion. One of the aims is also to promote the application of the Zpin composite technology in both military and civil fields. First, the functional requirements of the preinsertion machine were analyzed according to the preinsertion technology requirements of laminated composite members of the rectangletype aviation. Second, the mechanism motion scheme of the “shear after implant” combined camtype program was proposed for the preinsertion machine. The cam mechanism of the preinsertion machine was designed using the analytical method, and the theoretical profile curve of the cam mechanism was deduced. Third, the elastic dynamics model, including the clearance cam mechanism, was constructed. Next, the rotational speed of the combined cam was optimized, and its virtual prototype motion simulation was performed. Subsequently, the experimental prototype was designed and manufactured, and the correctness and rationality of the combined cam design were verified by conducting the implant experiment. The implant motion scheme was optimized according to the problems found in the experiment. The experimental results showed that the scheme could greatly improve the efficiency of the Zpin implantation. Its efficiency reached 5 080 mm2/min, the implantation success rate was controlled above 99%, and the implant parameters such as the implant spacing, implantation depth, and fiber length were controlled within ±0.01 mm. Hence, the preimplanting machine is easy to operate, humanmachine interfacefriendly, stable in longterm operation, and there are no problems such as Zpin breaking, which can meet the current requirements of implant efficiency and implantation accuracy of Zpin implanted devices.Keywords：Z-pin pre-insertion devices;combination cam mechanism;rectangular composite laminated component- 97
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Published：2020-08-13 -
Stereo matching method based on the plane constraint for lunar rover
Abstract：To meet the requirements of timeliness and reliability of the lunar rover system for obstacle detection, a semi-global stereo matching algorithm based on plane constraint and adaptive penalty coefficient is proposed. Firstly, the SIFT feature extraction and matching algorithm is used for the two images of epipolar rectification, and meanwhile edges are extracted. Secondly, the matched SIFT feature points is used to fit the plane, and the disparity search ranges of all pixels are estimated respectively in left and right images. Finally, based on the traditional semi-global matching algorithm, the adaptive penalty parameter strategy is applied to the stereo matching of the left and right images. The experimental results show that the algorithm can effectively reduce the computational complexity which is only 19.9% that of the traditional methods, and this method can obtain the correct matching results for the disparity discontinuous region and the occlusion region. Compared with the traditional semi global matching method, the processing speed and the matching accuracy are obviously improved. The method can lay the foundation for the further application.Keywords：lunar rover;stereo matching;plane fitting;semi-global matching;disparity map- 50
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Published：2020-08-13 -
Research on the Extraction Algorithm of Projected Circular Centers of Marked Points on the Planar Calibration Targets
Abstract：The planar targets with circular marked points are widely used in the camera calibration and visual measurement. Due to the planar targets, to get the real circular center in the image and improve the calibration precision, one circular center extraction method based on the geometric characteristics of dual conic is proposed. The key of this method is that the dual conic matrix of the marked point, A, in the image has a generalized eigenvector associated with the dual conic matrix of the marked point, B, in the image, and this generalized eigenvector passes through the two center projections of both points A and B. As a result, after getting the sub-pixel edge points and fitting the ellipse conic function, a vector linking the two center projections can be computed by the dual conics matrices of two marked points. And the standardized interpoint of the eigenvectors will be the center projection. To test the extraction accuracy of the center projection with the proposed method, the center projection of a huge marked point with a diameter 90mm is extracted when the relative angle between the CCD and the target plane is 40°, and the errors are within 0.1~1 pixel. Then the cameras’ parameters of a handheld scanner are calibrated with these center projections. Moreover, a 3D workpiece and the planar target with known marked points are scanned by the handheld scanner, the distance errors are within 0.2mm. By contrast, the extraction accuracy of this proposed method is higher than elliptical center as well as the precision of the camera calibration.Keywords：planar targets;marked-points;dual conic;camera model;projected center errors- 48
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Published：2020-08-13 -
Auto-focusing method of push-broom hyperspectral camera
Abstract：Auto-focusing method has been widely used in various optical instruments. Aiming at the problem of auto-focusing of push-broom hyperspectral camera, a method is proposed to estimate the focus of a camera by using the spectral quality evaluation function based on quaternion wavelet transform. Firstly, the single-line spectral data of the push sweep line is arranged into a two-dimensional matrix, and the matrix is decomposed into four low-frequency and high-frequency subbands. The spectral quality evaluation function is constructed by using the low-frequency and high-frequency amplitude and phase information to realize auto-focus. In the process of focusing, the spectral quality metrics is calculated in different focuses by rotating the lens at a certain stride length by an auto-focus mechanism. A Gaussian distribution function is fitted between the spectral quality metrics and the amount of expansion and contraction of lens. Finally, the optimal focus is estimated. Our results have shown that the proposed evaluation function of spectral quality has better sensitivity, accuracy. The auto-focus method has good accuracy due to using only a single line of spectral data for focusing.Keywords：hyperspectralCameras;spectrum analysis;evaluation methods;focusing;wavelet transforms- 131
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Published：2020-08-13 -
An approach to cross-company spacecraft software defect prediction
Abstract：In order to improve the efficiency and quality of aerospace software testing, an approach to cross-company aerospace software defect prediction is proposed, especially for the scarcity of within-company software and the long cycle of development. Considering the complexity, large scale and independent function of aerospace software, the idea of building a defect prediction model based on static classification is proposed. In this paper, the transfer learning method is introduced. Using the nearest neighbor classifier and data gravity model, the distribution characteristics of training data are corrected to improve the similarity between training data and target data. In order to improve the generalization ability of the model to adapt to the diversity of target data, a small amount of target data is added to the training data for model training. The approach is applied on the test of aerospace software testing. The results of application show that, compared with the existing software defect prediction methods, the proposed method can effectively improve the recall rate (close to 0.6) ever with a low false alarm rate (not higher than 0.3). The overall credibility is effectively enhanced (G- measure is over 0.6), and the method has high stability and strong generalization ability. This method can control the test scale in practical project and improve the test efficiency.Keywords：defect prediction;transfer learning;nearest neighbor classifier;data gravity;naive Bayes- 61
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Published：2020-08-13 -
Tensor Representation Based Target Detection for Hyperspectral Imagery
Abstract：Target detection for hyperspectral image(HSI) is a hot topic, due to its important military and civilian applications. This paper proposes a novel target detection algorithm for HSI based on tensor representation. The algorithm employs tensor analysis including CP decomposition and tensor block decomposition to implement blind source seperation to the hyperspectral data. Effective spatial and spectral features of blocks of local image were extracted. And then the algorithm establishes a detection model based on sparse representation and collaborative representation. Experiments were conducted to evaluate the performance of our approach under multiple scenes with complex background. From the visual representation of the results, it can be concluded that the proposed approach effectively extracts the spatial-spectral features under scenes with strong noise and complex background. The approach has good ability to suppress the background and the target is salient. In addition, the performance of the approach is evaluated by quatitative metrics such as receiver operating curve (ROC) and area under the ROC curve (AUC). Taking the popular HSI image-Sandiego image as an example, the approach achieves 90% detection rate with the false alarm rate of 10% and the AUC is greate than 0.95. Our approach ourperforms the other popular ones.Keywords：target detection;hyperspectral imagery;tensor representation;feature extraction;collaborative representation- 69
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Published：2020-08-13
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Ultraviolet detection and location of power line corona in UAV track
Abstract：To detect and locate the corona discharge of insulators quickly in unmanned aerial vehicle (UAV) power line inspection, a corona detection and location method for power lines in a UAV's track was investigated. First, the corona discharge power detection model was analyzed and established, and a formula for ultraviolet radiation power from a discharge source was obtained. Then, a corona detection device with high sensitivity was designed, and a positioning method for finding insulator defects in a UAV's trac Keywords：unmanned aerial vehicle track;ultraviolet;corona detection;location- 135
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Published：2020-08-13
Optics and Precision Engineering
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Design and test of electrostatic driving MOEMS arming device
Abstract：To improve the state control safety of a fuze and enhance its ability to resist electromagnetic interference, this paper proposes a silicon-based Micro-Opto-Electro-Mechanical Systems (MOEMS) arming device used in the miniature safety and arming system of a fuze. The device adopts two optical fibers as the carriers of energy transmission, and their misalignment and alignment are controlled through an electrostatic driving mechanism, which determines the safety and arming state of the fuze. The overall struc Keywords：Micro-Opto-Electro-Mechanical System(MOEMS);fuze;arming device;micro electrostatic driving mechanism;optical path coupled- 112
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Published：2020-08-13 -
Power failure compensation method for magnetically suspended TMP based on average power balance control
Abstract：High-speed magnetically suspended Turbo Molecular Pumps (TMPs) have been widely used in industrial applications for their high energy density, micro-vibration, and no lubrication requirements. However, the Active Magnetic Bearing (AMB) system will lose magnetic force once the main power fails, which may cause severe damage to the rotor and stator systems. In this study, an improved Power Failure Compensation Control (PFCC) method based on Average Power Balance Control (APBC) was proposed. First, a motor ene Keywords：magnetic bearings;DC/DC converter;motor energy feedback;Power Failure Compensation Control(PFCC)- 126
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Published：2020-08-13 -
Design of air-bearing simulator for free-flying robot
Abstract：To build a ground simulation experiment system for an in-orbit assembly, based on cold gas propulsion, we design a three-degrees-of-freedom free-flying robot simulator, and analyze the structural design, gas path system, dynamic modeling, and control system of the simulator. First, we adopt a modular design to partition the main structure of the simulator for different functions. Second, according to the working principle, we analyze and verify the bearing capacity of the simulator through an experiment. Su Keywords：space robots;three degree of freedom;simulator;cold gas propulsion;force distribution;structural design- 103
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Published：2020-08-13 -
Layout optimization of warping harness for segmented-mirror telescope
Abstract：To reduce the high costs of mirror polishing and opto-mechanical assembly, and to correct low-order aberrations caused by thermal and gravity deformation, the so called "warping harness" has been used to apply moment to the pivot of whiffletrees to achieve real-time correction of the mirror surface. Indeed, warping harnesses have been adopted in some large astronomical telescopes. This study aimed to optimize the layout of actuators that may be applied to large optical telescopes in China in the near future Keywords：segmented-mirror;warping harness;finite element method;reduction factor;mirror figuration analysis- 90
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Published：2020-08-13 -
Path planning of free-floating space robot based on control variable parameterization method
Abstract：Traditional path planning methods of a free-floating space robot cause severe disturbance to the base satellite. To solve this problem, a path planning method based on the parameterization of control variables is proposed. This method transforms the path planning problem into an optimal control problem using minimum base posture disturbance as an objective function along with a series of constraints. The control variable parameterization method is used to discretize the problem, and the optimal control prob Keywords：space free-floating robot;attitude disturbance;control variable parameterization;path planning- 131
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Published：2020-08-13 -
Design and implementation of combination cam-type Z-pin pre-insertion device for aeronautical materials
Abstract：In this study, a new high-efficiency and high-precision Z-pin pre-insertion based on a combination cam was developed to solve the problems, such as low efficiency, easy breaking, and slipping of Z-pin insertion. One of the aims is also to promote the application of the Z-pin composite technology in both military and civil fields. First, the functional requirements of the pre-insertion machine were analyzed according to the pre-insertion technology requirements of laminated composite members of the rectangle Keywords：Z-pin pre-insertion devices;combination cam mechanism;rectangular composite laminated component- 121
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Published：2020-08-13 -
Influence of driving forms on servo bandwidth in fast steering mirror
Abstract：To improve the servo bandwidth of fast steering mirrors with large stroke, a fast steering mirror with linear driving mode was proposed. Voice coil actuators were used to drive the fast steering mirror, and ball splines were used to constrain the direction of the drive, which transforms the traditional arc drive into a linear drive. First, the structure of a fast steering mirror driven by linearity was designed. Subsequently, the composition and characteristics of linear driving were analyzed. Subsequently, Keywords：fast steering mirror;linear driving;ball spline;servo bandwidth;mechanical resonance frequency- 109
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Published：2020-08-13 -
Variable stiffness characteristic analysis of a novel micro-nano probe with wire constraint suspension
Abstract：To address the problem that the stiffness of the probe support mechanism cannot be changed during the measurement process using a traditional micro-nano measuring device, a micro-nano probe with variable stiffness was designed based on the constraint support of the suspension wire. A piezoelectric device was employed to drive the compliant guide mechanism, which produces a displacement. Thus, the axial tension of the suspension wire changed. Based on the principle of stress stiffening, the transverse stiffn Keywords：variable stiffness;suspending wire support;compliant mechanism;stress stiffening;stiffness model- 81
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Published：2020-08-13 -
Multi-constrained intelligent trajectory planning for gliding missiles
Abstract：The terminal flight of the gliding missile involves high complexity, strong uncertainty, and many constraints. It is difficult to model and solve the corresponding trajectory planning and guidance problems. To increase the maneuvering range of the gliding missile and reduce the difficulty of trajectory planning, a multi-constrained trajectory intelligent planning method was proposed. This method included waypoint design and maneuverability prediction using the Continuous Deep Belief Network (CDBN). The CDBN Keywords：gliding missile;maneuverability prediction;continuous deep belief network;maneuvering trajectory planning- 112
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Published：2020-08-13
Micro/Nano Technology and Fine Mechanics
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Hyperspectral image restoration via weighted Schatten norm low-rank representation
Abstract：Hyperspectral Image (HSI) always suffers from various noises such as Gaussian noise, impulse, stripe noise, etc. To ensure the performance of subsequent applications, a new method for HSI restoration was proposed based on weighted Schatten norm Low-Rank Representation (LRR). The proposed method introduced the LRR model into the HSI restoration. It can accurately approximate rank using the weighted Schatten norm instead of the nuclear norm. Furthermore, the initial noiseless image was utilized as the diction Keywords：hyperspectral image;image restoration;low-rank representation;Schatten norm;Laplacian- 106
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Published：2020-08-13 -
Stereo matching method for lunar rover using the plane constraint
Abstract：To meet the requirements of timeliness and reliability of the lunar rover system for obstacle detection, a semi-global stereo-matching algorithm based on the plane constraint and adaptive penalty coefficient was proposed. First, the Scale Invariant Feature Transform (SIFT) feature extraction and matching algorithm was used with two images of epipolar rectification from which edges are extracted. Second, the matched SIFT feature points were used to fit the plane, and the disparity search ranges of all pixels Keywords：lunar rover;stereo matching;plane fitting;semi-global matching;disparity map- 109
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Published：2020-08-13 -
Research on extraction algorithm of projected circular centers of marked points on the planar calibration targets
Abstract：Planar targets with circular marked points are widely used in camera calibration and visual measurement. To obtain the real circular center in the image of a planar target and improve calibration precision, a circular center extraction method based on dual conic geometric characteristics was proposed. The key to this method was that the dual conic matrixCA* of the marked point A in the image has a generalized eigenvector associated with the dual conic matrix CB* of the marked point B in the image, and this Keywords：planar targets;marked-points;dual conic;camera model;projected center errors- 128
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Published：2020-08-13 -
Auto-focusing method of push-broom hyperspectral camera
Abstract：The auto-focusing method has been widely incorporated in various optical instruments. To address the issue of auto-focusing for push-broom hyperspectral cameras, a method was proposed for estimating the optimal focus of a camera by employing a spectral quality evaluation function based on quaternion wavelet transform. A single line spectral data of the push sweep line was transformed into a two-dimensional matrix, and the matrix was subsequently decomposed into four low frequency and high frequency sub-band Keywords：hyperspectral cameras;spectrum analysis;evaluation methods;focusing;wavelet transforms- 123
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Published：2020-08-13 -
Annealing analysis to long term SEUs for LEO satellite
Abstract：To examine the annealing effect of Single Event Upsets (SEU), a single device from a Low Earth Orbit (LEO) satellite running in sun-synchronous orbit for more than nine years was selected as a sample. The working temperature from satellite telemetry data was investigated, and details of the SEU nadir and time were discussed in relation to the geomagnetic field, F10.7, neutrons monitoring data, etc. By averaging the SEU time intervals, a model was developed to estimate the annealing characteristics, and this Keywords：space environment;Low Earth Orbit(LEO);Single Event Upset(SEU);annealing effect;estimation- 101
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Published：2020-08-13 -
Approach to cross-company spacecraft software defect prediction based on transfer learning
Abstract：In order to improve the efficiency and quality of aerospace software testing, an approach to cross-company aerospace software defect prediction was proposed, especially for the scarcity of within-company software and the long cycle of development. Considering the complexity, large scale, and independent functions of aerospace software, the idea of building a defect prediction model based on static classification was proposed. In this paper, the transfer learning method was introduced. Using the nearest neig Keywords：defect prediction;transfer learning;nearest neighbor classifier;data gravity;naive Bayes- 127
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Published：2020-08-13 -
Attitude accuracy analysis of PnP based on error propagation theory
Abstract：Based on the error relation of a group of typical characteristic points, the most favorable function relation between indirect measurement and direct measurement was established, and the error influence of other characteristic points was synthesized according to the error propagation theory. Finally, a new method of error step-by-step analysis of the PNP problem with complete azimuth, pitch, and tilt angle error analysis model was proposed. Taking the P4P problem as an example, the analytical formulas of th Keywords：monocular vision measurement;perspective-n-points problem;accuracy analysis;error propagation theory;indirect attitude measurement- 152
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Published：2020-08-13 -
Tensor representation based target detection for hyperspectral imagery
Abstract：Target detection for Hyperspectral Images (HSIs) is gaining importance owing to its important military and civilian applications. This study proposed a novel target detection algorithm for HSIs based on tensor representation. The algorithm employed tensor analysis including CP and tensor block decompositions to implement blind source separation on hyperspectral data. First, effective spatial and spectral features of the blocks of local images were extracted. Then, a detection model based on sparse and colla Keywords：target detection;hyperspectral imagery;tensor representation;feature extraction;collaborative representation- 87
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Published：2020-08-13 -
Underwater image restoration with adaptive background light estimation and non-local prior
Abstract：It is significant to realize effective single underwater image restoration for acquiring clear image in underwater exploration and underwater environment monitoring field. Most existing algorithms use dark channel priors to restore images, which lead to inaccurate estimates of the background light and transmission map. Hence, a novel method with adaptive background light estimation and nonlocal prior was proposed. Firstly, the candidate water light regions could be obtained by a threshold segmentation algor Keywords：underwater imaging;machine vision;non-local prior;guided filter;image restoration- 147
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Published：2020-08-13
Information Sciences
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