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Issue 12 ， 2018
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Reflective shearing point diffraction interferometer for phase defect measurement
Abstract：In order to realize a large field, high resolution, and dynamic measurement of phase defects of optical components, a Reflective Shearing Point Diffraction Interferometer (RSPDI) was proposed. A lateral shear amount was introduced between the test and reference light to generate a high-density linear carrier frequency, and the information of the wavefront under the test was extracted from a single interferogram by an fast Fourier transform algorithm to determine the simultaneous measurement of the defects. Keywords：interferometry;simultaneous measurement;point diffraction;phase defect;lensless imaging- 87
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Published：2020-07-05 -
Haze and transmittance real-time tester for curved-surface and transparent samples
Abstract：In order to realize the real-time measurement of haze and light transmittance for large-surface transparent samples, a haze and transmittance tester using LED as the light source and a double integrating sphere as the signal measurement part was designed. First, the theoretical derivation of the light transmittance and haze was completed on the basis of the system scheme. Second, simulation analysis of the light source spectral distribution affecting measurement, optical design, integrating sphere parameter Keywords：photometry;haze;transmittance;double integrating sphere- 108
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Published：2020-07-05 -
Spectral compression of XeF(C-A) excimer laser using grating resonator with an intra-cavity etalon
Abstract：In order to improve the signal-to-noise ratio for laser applications underwater, a grating resonator with an intra-cavity etalon was designed to compress the spectrum of XeF blue-green laser. First, a grating resonator was used to obtain a sub-nanometer laser linewidth, and then, a further spectral compression was performed by inserting an etalon into the grating resonator. The experimental results show that a linewidth of 0.14 nm can be obtained by using a 1 200 line/mm grating, and the linewidth can be further compressed to 39 pm by inserting an etalon, with a reflectivity of 50%, in the grating resonator. The final laser pulse energy is about 65 mJ and the pulse duration is 1 μs. Although the gain coefficient of the XeF (C-A) laser is low, the optical loss of the resonator can be reasonably controlled by optimizing the working parameters of the grating and the etalon, thereby a 10 pm-level laser linewidth can be realized.Keywords：laser technology;XeF laser;low gain coefficient;spectral compression- 142
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- 12
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Published：2020-07-05 -
Solution of liquid crystal phased array director and its beam deflection
Abstract：To analyze the relationship between the spatial light modulation characteristics of a liquid crystal phased array and the driving voltage using the liquid crystal continuous elastic deformation theory, in this paper, a method for solving the spatial distribution of a differential iteration liquid crystal director was proposed based on nonlinear least squares. Based on the electro-optical properties of the liquid crystal material, the distribution of the liquid crystal director at the threshold voltage was u Keywords：liquid crystal phased array;phase delay;Nonlinear Least Square(NLS);director;beam steering- 83
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Published：2020-07-05 -
Optical measurement of mass transfer between gas and liquid phases in hydraulic circuits
Abstract：In order to study the mass transfer between the free gas and oil in a fluid power system and realize bubble mass measurement in oil, the radius limit of the bubble during measurement was derived from steady state and zero temperature gradient conditions. A high-pressure gas-oil mass transfer optical measurement system was designed, and the key algorithms for bubble identification and tracking were studied. First, the radius limit of a bubble during measurement was derived from the Biot number and Newton's L Keywords：optical measurement;fluid compressibility;gas-oil mass transfer- 76
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Published：2020-07-05 -
Forward measurement of submarine gas hydrates by active remote sensing technology
Abstract：In this paper, an optical imaging interferometry system was proposed for the accurate detection of the temperature, pressure, and concentration of gas hydrates. As part of this system, laser light with a wavelength of 1.65μm, was transmitted across the sea surface through a fiber to excite gas hydrates on the sea bed. Ten spectral lines close to the 1.65μm waves emitted by CH4 were collected and transmitted to the sea surface through another fiber. Five image interference fringes for CH4 were obtained on a Keywords：optical remote sensing;gas hydrate;temperature;concentration;pressure- 86
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Published：2020-07-05 -
GaN based metalens for micro imaging
Abstract：A metalens consisting of GaN nanopillars as basic cells was designed for subwavelength focusing at visible wavelengths, which provided an improvement over bulky and low-efficiency conventional imaging systems, and the possibility of its application to micro imaging. The metalens is composed of a GaN nanopillar array, which maintains the same height but gradually varying width. An analysis of the capacity and reasons for GaN nanopillars controlling the phase of incoming light was performed. In addition, base Keywords：metalens;subwavelength focusing;GaN;finite-difference time-domain simulation- 105
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- 23
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- 1
Published：2020-07-05
Modern Applied Optics
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Fast trajectory-orbit unified design for spacecrafts
Abstract：To improve the rapid response of a spacecraft and ensure that its trajectory-orbit unified design meets the requirements of speed, accuracy, and reliability, a rapid trajectory-orbit unified design method for spacecrafts was studied. First, the dynamic model of a spacecraft was constructed. The process and terminal constraints required for a spacecraft's trajectory-orbit unified design were analyzed and its flight procedure was given. Then, the traditional trajectory design numerical solution was improved. Keywords：trajectory-orbit unified design;spacecraft;numerical method;multi-level iterative- 96
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- 16
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Published：2020-07-05 -
Six-degree-of-freedom displacement and angle measurement system based on two-dimensional position-sensitive detector
Abstract：A Position-Sensitive Detector (PSD) was used to measure two-dimensional displacement with high precision. A combination of three two-dimensional PSDs can implement measurements of six-degree-of-freedom relative displacement and angle. The measurement system mainly comprises three PSD sensors (including PSD photosensitive surface and light-emitting tube), low noise signal conditioning, and an Analog to Digital(AD) acquisition circuit. Three PSD orthogonal layout schemes were used to calculate the displacemen Keywords：position sensitive detector;three-dimensional displacement measurement;movement measurement;reliability evaluation- 105
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Published：2020-07-05 -
Mechanism design and kinematic analysis of deployable solid reflector mechanism
Abstract：To solve the problems of low accuracy and folding rate of the main reflective surface of a traditional solid reflector mechanism, a deployable solid reflector mechanism was designed in this paper. First, the configurations of four types of deployable units were proposed, and their degrees of freedom were analyzed. After comparing and analyzing the advantages and disadvantages of the configuration schemes, configuration scheme 4 was defined as the basic configuration of the deployable unit, and its structure Keywords：solid reflector mechanism;deployable unit;kinematic analysis;rotation angle;structure size;folding rate- 142
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- 15
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Published：2020-07-05 -
Application of neural network-based nonlinear intelligent control in electro-optical tracking systems
Abstract：A neural network-based nonlinear intelligent control method was proposed for electro-optical (EO) tracking systems to overcome the performance reduction caused by the complex nonlinearity existent in real systems. A radial basis function neural network supervisory control structure was employed, and the associated advantages and characteristics were expatiated in the proposed study. Furthermore, a tracking experiment was conducted for performance evaluation. The obtained experimental results demonstrate tha Keywords：electro-optical tracking system;neural network;nonlinear control;intelligent control- 102
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- 19
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Published：2020-07-05 -
Development of focusing mechanism for space camera
Abstract：A small amount of defocus is generated in the optical system of high-resolution space cameras owing to the harsh mechanical environment of the launch section and the complex temperature environment of the orbit. To ensure the image quality of the camera and correct the defocus, a new high-precision focusing mechanism, consisting of a worm gear and a cam slider, was designed. The first stage of deceleration was achieved through the worm gear in this design. The drive's rotary axis was orthogonal to the optic Keywords：space camera;focusing mechanism;environmental test;error analysis;worm gear- 99
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- 19
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- 4
Published：2020-07-05 -
Automatic comprehensive noncontact measurement and solution method for cylindrical workpieces without targets
Abstract：During the automatic docking of cylindrical workpieces, it may be necessary to measure the orientation of workpieces accurately without targets. For this reason, a precision scanning method without targets was utilized. The point cloud data was obtained by a laser profile sensor, and the postures were determined by a comprehensive method. Based on Monte-Carlo simulation, the accuracies of the axis fitting method and bus section fitting method were compared, and a new comprehensive method was proposed furthe Keywords：noncontact measurement;laser profile sensor;precision scanning measurement- 70
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Published：2020-07-05 -
Forward kinematics of Stewart parallel manipulator based on step-adjusting Newton method
Abstract：Forward kinematics of the near singular position of the Stewart parallel manipulator based on the Newton method or quasi-Newton method are not converge; Newton downhill method is time-consuming, sometimes. To resolve the situation, a method of applying the step-adjusting Newton method to a parallel manipulator is proposed. Firstly, the process of forward kinematics of the Stewart parallel manipulator based on the step-adjusting Newton method was designed. Then, the fewest iterative steps in the forward kine Keywords：forward kinematics;Stewart parallel manipulator;step-adjusting newton method;step-matrix- 79
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Published：2020-07-05 -
Magnetostrictive tactile sensor for texture detection
Abstract：Texture is the embodiment of the distribution of surface microstructure. Tactile texture is a crucial factor to consider for improvement of the perception and exerting control over the environment of the material. In this study, a highly accurate and responsive tactile sensor was designed and fabricated using the inverse magnetostrictive effect of Galfenol to detect the surface microstructure of different objects and determine their roughness and fine density. Based on the Euler-Bernoulli beam dynamics theo Keywords：Galfenol;magnetostrictive inverse effect;texture detection;roughness;fine density- 189
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Published：2020-07-05 -
Analysis of roughness and morphology of metal surface grooves by micro milling
Abstract：In order to improve the surface quality of micro machined parts, micro milling experiments were designed to study the variations of surface roughness and sidewall residual burrs of micro grooves. First, from a theoretical point of view, the model of processed surface formation and micro machined surface roughness theory were introduced for the purpose of proposing changes to the sidewall for tool run-out. Then, typical parts were selected to process the micro straight grooves by the developed 3-axis linkage Keywords：surface roughness;milling parameters;milling thickness;tool run-out- 146
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- 15
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- 4
Published：2020-07-05
Micro/Nano Technology and Fine Mechanics
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S-curve trajectory planning and high-precision control of precision servo turntable
Abstract：Trajectory accuracy is an important performance indicator for precision turntables. To improve the motion accuracy, this study improves the traditional control algorithm from the perspective of trajectory planning and motion control. For trajectory planning, the S-curve trajectory planning equations are deduced, and the trajectory planning parameter values are given in combination with the dynamic constraints of the turntable. This provides the motion control algorithm with trajectory commands that meet the Keywords：precision turntable;motion accuracy;S-curve trajectory planning;dynamic constraints;DOB;feedforward compensation- 111
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- 7
Published：2020-07-05
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On-orbit modulation transfer function measurements based on lunar limb for FY-2G
Abstract：The modulation transfer function (MTF) is an important indicator that describes the performance of an optical imaging system. To avoid the effect of atmosphere on the measurement readings obtained by the on-orbit MTF on a meteorological satellite, the calculation method considering the lunar limb is investigated. First, we select the moon image obtained by FY-2G/VISSR as the input for the Knife-edge method. Then, we separate the image into sub-images according to different pixels of the detectors. Finally, based on different sets of sub-images, we obtain different results, which can improve the comprehensiveness of the MTF results. The experiments indicate that the result calculated by the Moon image is better than the result from the Earth image, which are 0.320 1 and 0.216 4, respectively. The standard deviation of MTF results from continuous sub-image is 0.013 31, which indicates the stability of performance of the system.Keywords：knife-edge;lunar limb image;remoting optical system;modulation transfer function- 119
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Published：2020-07-05 -
Design of high-sensitivity EMCCD navigation camera
Abstract：The navigation camera is a sensitive component that is crucial for deep space exploration. This report describes a method for the comprehensive improvement of the performance of such a camera by increasing their sensitivity. In particular, the approach improves the temporal resolution of this instrument and simultaneously solves the target detection problem under high dynamic conditions. Firstly, the imaging quality of a navigation camera is analyzed according to the operating mode and the performance chara Keywords：deep-space exploration;navigation camera;Electron-Multiplying Charge-coupled Device(EMCCD);high dynamic;small celestial bodies- 78
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- 19
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- 4
Published：2020-07-05 -
Median filtering algorithm for adaptive window shape
Abstract：While removing noise, the loss of useful information is inevitable, especially the edge information of linear images. To maximize the image and minimize the loss of useful information according to the edge features of the testing image, a window with appropriate size and shape was selected to perform median filtering and other operations. It is innovatively proposed to apply a Hough transform to the filtering window shape selection of the wheel crack CT image, aiming at the image of the single direction con Keywords：median filtering;shape of filter window;targeted filtering;Hough transform;pixel gradient- 156
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Published：2020-07-05 -
Pedestrian intruding railway clearance classification algorithm based on improved deep convolutional network
Abstract：Objects intruding railway clearance pose great threat to normal railway operations. Identifying intruding pedestrians within the railway clearance limit was of great significance to ensure the safety of railway operations. The existing railway intrusion detection system only detected the intrusion, but did not distinguish whether it was a true alarm of pedestrian intrusion or false alarm caused by light interferences. To reduce false alarms, a training and test set of the alarm image samples were establishe Keywords：railway objects classification and identification;pedestrian detection;deep convolutional network;HOG combined features- 104
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- 14
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- 7
Published：2020-07-05 -
High-dynamic range scenes reproduction based on hybrid mapping
Abstract：High dynamic range (HDR) scene reproduction has been widely used in consumer electronics, virtual reality, photography, and computer vision. An HDR scene reproduction algorithm based on hybrid mapping was proposed to address the problem of poor overall appearance and local details of an existing work. First, HDR scenes were transformed from the RGB to HSV color space, which converts the color information to hue, saturation, and luminance value components. Second, the luminance values were transformed into a Keywords：high dynamic range scenes;hybrid mapping;guided filter;single-scale Retinex;HSV colour space- 82
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Published：2020-07-05 -
Elemental image array coding combining imaging geometry features
Abstract：To solve the problems of storage and transmission of elemental image arrays in the integrated imaging system, an elemental image array coding and decoding algorithm that combines imaging geometry features was proposed. First, the offset of the corresponding image points in different elemental images were determined according to relevant physical parameters in the process of collecting the elemental image arrays. In addition, adjacent elemental images of each row in the element image arrays were grouped, and Keywords：elemental image array;geometric feature;corresponding image points;High Efficiency Video Coding (HEVC);coding- 86
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Published：2020-07-05
Information Sciences
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High-confidence correlation tracking algorithm based on PSR and objective similarity
Abstract：To prevent over-deformation and to solve occlusion problems that are difficult to solve for correlated filtering tracking algorithms in the tracking field, an improved multiscale target tracking algorithm based on PSR and objective similarity was proposed in this paper. The proposed method combined a traditional correlation operation, peak side lobe ratio, with a perceptual hashing algorithm to tackle problems such as target occlusion, over deformation, and other complex scene judgments. Experimental results using the OTB-2015 demonstrate proposed algorithm's reliability and integrity of the target trajectory. The accuracy and robustness of our algorithm is better than that of Kernelized Correlation Filter (KCF) tracking algorithms. This paper presents a novel idea for occlusion detection in the target tracking field.Keywords：computer vision;target tracking algorithm;accuracy judgment;anti occlusion- 126
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Published：2020-07-05 -
Signal processing algorithm of a single-track absolute encoder for photoelectrical theodolite
Abstract：To realize a fast and high-precision angular measurement method, this study focused on the signal processing algorithm of a single-track absolute encoder, which can be easily applied to photoelectrical theodolites. Using this algorithm, the grating line center and pulse width could be quickly estimated with only two sampling points of the rising and falling edges, by setting a threshold for the observed grating data. To improve the existing subdivision method, a high-resolution subdivision algorithm for ang Keywords：precision measurement;single-track absolute encoder;signal processing;photoelectrical theodolite- 87
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- 12
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Published：2020-07-05 -
Automatic fault recognition algorithm for key parts of train based on sparse coding based spatial pyramid matching and GA-SVM
Abstract：A general automatic fault recognition algorithm based on sparse-coding-based spatial pyramid matching and Genetic Algorithm Optimized Support Vector Machine (GA-SVM) was proposed for fault detection of the bogie block key, dust collector, and fastening bolt in the Trouble of moving Freight car Detection System (TFDS). First, the image of a sample was divided into patch areas in different scale spaces, and the Scale-Invariant Feature Transforms (SIFT) of each patch area was extracted. Sparse coding was then Keywords：Trouble of Moving Freight Car Detection System(TFDS);sparse coding;space pyramid;Scale-invariant Feature Transform(SIFT);genetic algorithm;Support Vector Machine(SVM)- 104
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- 16
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Published：2020-07-05 -
Scene classification of remote sensing images based on multiscale features fusion
Abstract：To solve the low accuracy problem of remote sensing image scene classification due to small sample sizes, a classification method was proposed based on Multiscale Features Fusion (MSFF). First, the remote sensing images were scaled to obtain several different scale images of the same remote sensing image. Thereafter, they were inputted into a Deep Convolutional Neural Network (DCNN) for convolutional operation, and the different scale features of the convolutional and the fully connected layers were reduced Keywords：remote sensing image;scene classification;deep convolutional al neural network;features fusion;multi-kernel support vector machine- 114
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Published：2020-07-05 -
Ultrasonic detection method of micro defects in thick-section CFRP
Abstract：To detect micro defects in thick-section carbon fiber reinforced composite (CFRP), the recurrence analysis method was used to analyze ultrasonic signals of tested CFRP. First, small holes were made to simulate micro defects, and an ultrasonic pulse echo method was adopted to test these simulated defects of different sizes. Then, the signal segments around the defect position were selected, and recurrence analysis was performed after proper parameters like embedding dimension(m), time delay(τ), and threshold Keywords：thick section CFRP;micro defects;pulse echo method;recurrence plot;recurrence quantification analysis- 74
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Published：2020-07-05
Information science
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