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Issue 2 ， 2018
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Effects of wavelength shift and energy fluctuation on inversion of NO2 differential absorption lidar
Abstract：To evaluate the effect of the stability of the laser on the inversion of the NO2 distribution in differential absorption based on the NO2 absorption spectrum and the lidar equation. The relative errors caused by wavelength shift and energy fluctuation in the range resolved differential absorption lidar were analyzed. Two Nd:YAG lasers are used to pump into two dye lasers to produce two wavelengths, λon (448.1 nm) and λoff (446.6 nm), respectively. In the absence of frequency and power stability conditions, Keywords：lidar;differential absorption spectrum;NO2;wavelength drift;energy fluctuation- 109
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Published：2020-07-05
Modern Applied Opitics
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Influence of space charge effect on temporal-spatial performance of pulse-dilation framing tube
Abstract：X-Ray framing cameras are an important two-dimensional ultrafast diagnostic tool in inertial confined fusion experiments. Although the temporal performance of framing cameras is further improved by the long drift area, the space charge effect (SCE) is increased as well. In order to study the influence of SCE on the framing tube, similar to the magnetic focused framing tube, for example, the temporal dispersion and spatial dispersion of SCE are studied using the mean field model, electron trajectory, and ima Keywords：optoelectronics and laser technology;space charge effect;mean field model;pulse-dilation framing tube;temporal resolution;spatial resolution- 101
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Published：2020-07-05 -
Difference field scattering properties between multiple inlaid redundant particles and slightly rough optical surface
Abstract：In order to provide a theoretical basis for nondestructive examination, a calculation model for the difference scattering fields between a slightly rough optical surface and multiple inlaid defect particles is established by the finite difference time domain (FDTD) method. The Monte Carlo method is used to solve the problem of the optical surface with roughness. Moreover, the difference radar cross section is added into the half-space model to analyze the selected calculations for the effects of sizes, separation distances, numbers, and incident angles of the defects. The numerical results are analyzed in detail to determine the best position to find the defects in the optical surface by detecting in fixed steps of 20° for the incident angle. The work done in this paper will provide a theoretical basis and technological support for the fields of nondestructive examination, optical film, optical performance design of micro-/nano-structures, among others.Keywords：difference scattering field;multiple inlaid particles;half-space finite difference time domain(FDTD);slightly rough optical surface- 63
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Published：2020-07-05 -
Experimental demonstration of differential synthetic aperture ladar imaging at very low return level
Abstract：Weak echo signal and motion errors are the features of differential synthetic aperture ladar (DSAL) that should be addressed in its future application scenarios. To achieve this, a laboratory DSAL demonstration of random piston motion target at very low return level is reported. Using 1 550 nm laser source, a DSAL imaging setup is built, with receiving apertures spacing of 188 μm and target distance of 2.4 m. The transmitted laser power is attenuated by adding a polarizer to the transmitter and random pisto Keywords：ladar;differential synthetic aperture;experimental demonstration;weak echo;random piston motion- 157
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Published：2020-07-05 -
Balanced amplified photodetector with low phase noise and large area
Abstract：In order to achieve accurate phase detection of diverging and rapidly modulated light signals in optically pumped atom magnetometer systems and to solve the problems of existing commercial balance photodetectors in terms of small optical sensitive area, small gain, small bandwidth, and poor phase performance, the balanced differential detection method based on Kirchhoff's law is adopted in this paper. The mechanism for system common mode noise suppression is analyzed and a low phase noise balanced amplified Keywords：balanced photodetector;optically pumped atomic magnetometer;phase detection;low phase noise;phase drift;large area- 84
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Published：2020-07-05 -
Single longitudinal mode TEA CO2 laser based on transmissive unstable resonator
Abstract：In order to obtain a high-quality single-longitudinal-mode output from a TEA CO2 laser, a study on a TEA CO2 laser with seed injection locking is carried out. A virtual confocal resonator with transmission coupling is proposed. The evolution of the cavity mode is simulated by Prony's method of the Glad software. The near-field and far-field intensity distributions are recorded experimentally. The results demonstrate that the simulation results are in good agreement with the experimental results, which verif Keywords：TEA CO2 lasers;unstable resonator;injection-locked;single longitudinal mode- 99
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- 19
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Published：2020-07-05 -
Measurement of infrared refractive index based on angle location automatic recognition
Abstract：In order to determine the refractive index of bulk glasses in the infrared band, a refractive index measurement system based on the optical auto-collimation principle is proposed. We use a liquid-nitrogen-cooled mercury telluride detector and a special optical architecture to collect high-resolution light intensity information. The angle information is converted to digital information by a data acquisition card. A precision stepper motor drive control system is used to synchronize the light intensity signal Keywords：infrared optical materials;chalcogenide glass;refractive index measurement;autocollimation refractometric method- 85
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- 12
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Published：2020-07-05 -
Solar simulator based on LED array light source
Abstract：Addressing the deficiencies of solar simulators, such as low radiation intensity and poor spectral matching, an LED solar simulator consisting of an LED array light source module, Fresnel focusing lens, optical integrator, and collimator lens is proposed. Firstly, according to the principle of multispectral fitting, 15 LED light sources with different wavelengths are optimally selected in the spectral range of 400-1 100 nm, and their light source power is calculated to realize an exact match of the solar sp Keywords：solar simulator;LED array light source;optical system;Fresnel lens;optical integrator- 142
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- 15
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Published：2020-07-05 -
Panoramic imagers with two fields of view and non-blind area
Abstract：Aiming at the well known drawback of the catadioptric panoramic imaging technology, which has an observation blind area in front of the optical system, a new panoramic imager which has dual observation modes was designed in this paper. Compared with the traditional catadioptric panoramic imager, the instrument proposed could observe the forward 360°×(0°-55°) field of view and ring 360°×(55°-95°) field of view simultaneously. The forward field of view was a good complement to the central observation blind spot in ring field of view, which increased the utilization of CCD detector. The imaging instrument optical system consisted of a front lens group, a panoramic annular lens and a relay imaging system, and all surfaces of the optical system were spherical. The mechanical structure of the new optical system was designed as well. This paper provides a new design method for the catadioptric panoramic imaging technology.Keywords：optical system design;two fields of view;non-blind area;forward field of view;ring field of view;panoramic annular lens;mechanical structure- 75
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Published：2020-07-05 -
Three dimensional in-situ stress sensor based on optical fiber sensing technology
Abstract：In order to realize the effective monitoring of the spatial stress state of the underground rock formation and its variation. A monitoring method combining plane strain and fiber grating sensing technology was proposed, based on the principle of fiber grating sensing and plane stress state measurement. The strain sensor unit was composed of two sets of strain sensor, which were composed of two sets of right angle strain flower and a group of equiaxed strain flower. The three sets of strain flowers were plac Keywords：optical fiber sensing;Fiber Bragg Grating(FBG);spatial stress of subsurface rock;carbon fiber material;strain flowers;strain sensor unit- 236
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- 18
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Published：2020-07-05
Modern Applied Optics
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Design and simulation of morphing nose cone for umbrella guide-rod mechanism
Abstract：The morphing nose cone for aerospace vehicle will provide a novel way for improving aerodynamic performance of reentry vehicle. In order to realize adaptability of the aerospace vehicle to the complex environment, a morphing nose cone of aerospace vehicle was presented by using a series of umbrella guide-rod mechanisms, and its kinematic characteristics and system stability were analyzed. Kinematic simulation analysis of the morphing nose cone under different driving modes was carried out to find out the influence of the main factors on its operation performance and system stability. Simulation results showed that the elongation and the deflection of the morphing nose cone were 1 499.6 mm and 500.7 mm, respectively, which meet the requirements of design. Comparing with driving mode of the constant speed, driving mode of the sinusoidal motion can makes the morphing nose cone running more stable.Keywords：aerospace vehicle;morphing nose cone;guided-rod mechanism;kinematic analysis- 77
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- 15
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- 2
Published：2020-07-05 -
Hartley eddy current sensor used in maglev molecular pump
Abstract：For the displacement sensor used in maglev molecular pump in the industrial field, in addition to good static characteristic and high dynamic characteristic requirements, its volume also affects the pumping speed, the vacuum and the compression ratio of the maglev molecular pump. Aiming at the high-vacuum maglev molecular pump, a design method of the eddy current displacement sensor (ECDS) based on the Hartley oscillator was proposed. The symmetrical probes were connected into the same oscillation circuit a Keywords：maglev molecular pump;Eddy Current Displacement Senor(ECDS);Hartley;volume;dynamic characteristic- 83
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- 14
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Published：2020-07-05 -
Evaluation and test of self-locking ability for focusing mechanism of space camera
Abstract：Focusing mechanisms in space camera needs to possess self-locking ability to resist the shock and vibration in the process of launching. Therefore, a self-locking analysis on the mechanism is the key of ensuring the space optics remote sensors work properly. This paper studied the sliding mechanism of thread contact surface under environments of vibration, and built a engineering models of the focusing mechanism of certain space camera with two types of screw pitch (1 mm, 1.5 mm). Contact stress, shear stre Keywords：space camera;focusing mechanism;self-lock;screw thread;random variation- 88
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- 31
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Published：2020-07-05 -
Position measurement of linear electric motor rotor based on restoration of motion blur speckle
Abstract：Image measuring technique is more and more applied to the double secondary permanent magnet linear motor rotor position detection because of the advantages of non-contact and anti-interference. Aiming to the motion blur problem of image acquisition process, an accuration identification method of motion blur parameters was proposed to realize the precise measurement of linear electric motor rotor position. By using digital speckle image as the original photo surface, the motor rotor position information of s Keywords：linear electric motor;position measurement;parameter identification;Singular Value Decomposition(SVD);Principal Component Analysis(PCA)- 104
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- 14
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- 3
Published：2020-07-05 -
Aluminum nitride Lamb wave piezoelectric resonators based on ultrathin silicon substrates
Abstract：In order to achieve the performance requirements of piezoelectric acoustic Lame wave sensor with high quality factor (Q factor), low limit of detection (LOD) and easy integration, a method was presented in the paper. First, an ultrathin and uniform 2 μm-thick silicon substrate was obtained by dry etching of handling silicon layer and automatic stopping of boxing layer based on SOI (Silicon-on-insulator) wafer, and then a 2 μm-thick Aluminum Nitride (AlN) piezoelectric thin film with high C axis oriented was Keywords：piezoelectric resonator;thin film Lamb wave;AlN;SOI silicon wafer;quality factor;trace moisture detection- 116
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Published：2020-07-05 -
Three-phase abrasive flow polishing and distribution characteristics of bubble collapse
Abstract：To resolve the low processing efficiency of softness abrasive flow method (SAF) for hard brittle materials, a gas-liquid-solid three-phase abrasive flow processing method (GLSP) was proposed. Through injecting the micro bubbles into processing flow field and by means of the bubble collapse energy, the processing capability of abrasive flow could be strengthened. The fluid mechanics model of GLSP was established based on computational fluid dynamics-population balance model (CFD-PBM) coupled method. The simu Keywords：hard brittle materials processing;softness abrasive flow;gas-liquid-solid three-phase abrasive flow;bubble collapse- 80
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- 11
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Published：2020-07-05 -
Novel internal Lorentz magnetic bearing for magnetic bearing gyrowheel
Abstract：To remedy the limitations of external Lorentz magnetic bearing with poor gas flux density uniformity, an internal Lorentz magnetic bearing for magnetic bearing gyrowheel was presented. The three dimensional finite element method was used for analysis of the gas flux densities of two schemes. The gas flux density rates of internal scheme in circumferential and longitudinal directions were 0.8% and 8.4%, less than that of extern scheme of 15.0% and 23.7%, respectively. The integration method was applied to ac Keywords：magnetic bearing gyrowheel;magnetic bearing;Lorentz force;finite element analysis;space application- 79
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Published：2020-07-05 -
Study on boresight stabilized technology of vehicle photoelectric reconnaissance platform
Abstract：In order to improve the ability of anti-disturbance of the servo control system for photoelectric platform, an improved velocity loop based on ADRC method was presented. Firstly, the analyses of boresight stability loop of the photoelectric platform were conducted to simplified its mathematical model. Then the general disturbance was introduced by analyzing the disturbance mechanism in servo control system. Secondly, a new controller based on a reduced-order ESO was designed, and was applied to the improved Keywords：photoelectric platform;reduced-order ESO;improved velocity loop;feedforward compensation;disturbance resistance capacity- 96
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Published：2020-07-05 -
Polar radius moment invariants criterion for identifying bearing early failure by chaotic oscillator
Abstract：The existing methods for detecting bearing faults based on chaotic oscillators have been successfully applied. The key step of the method is to distinguish the phase transition of chaotic oscillators. Lyapunov exponents are usually used to judge the transformation, which is complicated and time-consuming. Starting with image recognition, an identification method based on polar radius invariant moment parameter for phase transformation was proposed. The Duffing chaotic oscillator was constructed, and the rel Keywords：early fault diagnosis;chaotic oscillator;polar radius invariant moment- 96
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Published：2020-07-05
Micro/Nano Technology and Fine Mechanics
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An accurate analytical expression for predicting the performance of piezoelectric cantilever based actuators and sensors
Abstract：The deformation of the three-layered piezoelectric beam in the electric field will arise the induced potential, and then change the distribution of the whole structural electric potential. Considering the coupling effect of the deformation and potential, the accurate analytical expressions, based on the Euler-Bernoulli beam theory, for predicting the performance of three-layered piezoelectric cantilever actuators and sensors, were derived. In the derivation process, the governing equation of three-layered p Keywords：piezoelectric beam;actuator;sensor;analytical solution- 112
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Published：2020-07-05
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Adaptive hyperspectral image classification using region-growing techniques
Abstract：Aiming at the problem of segmentation parameters setting in object-oriented hyperspectral classification method, an adaptive hyperspectral classification algorithm based on region-growing techniques was proposed in this paper. Firstly, a constrained region-growing method was proposed, which used the spatial information of the training samples to provide effective constraints, thus reducing the error propagation rate of the region markers in the region-growing process, and improving classification performanc Keywords：hyperspectral;classification;object-oriented;region-growing;adaptive- 90
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Published：2020-07-05 -
Calibration parameters of long focal aerial mapping camera by means of calibration field
Abstract：A two-step method was proposed to estimate parameters of long focal mapping camera by means of calibration field. The direct linear transform formulation(DLT) was used to obtain initial values for the hybrid LMQN iterative speed method by giving the feature points and the images taken from several positions and attitudes, and the whole process of calculating and experiment was described in detail. Compared with precise angle measurement method, operation and recording of accurate equipment are dispensable. Keywords：focal aerial mapping camera calibration;calibration field;camera parameters;Hybrid LMQN method- 98
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Published：2020-07-05 -
Rectification of 3D Lying Craniofacial Model Based on Geodesic
Abstract：The three-dimensional craniofacial soft tissue shapes in the upright and lying postures are different due to the gravity. In order to rectify the three-dimensional craniofacial model from the lying posture to one from the upright posture, a rectification technique of three-dimensional craniofacial models based on geodesic was proposed. Firstly, the correspondences of the craniofacial feature points under two postures were established by using the intrinsic geometric invariance of geodesic distance; Secondly Keywords：craniofacial reconstruction;geodesic;model rectification- 174
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Published：2020-07-05 -
Spatial-spectral discriminant analysis for hyperspectral image classification
Abstract：The traditional hyperspectral image classification methods consider only spectral information while spatial information is ignored. To address this problem, a semi-supervised spatial-spectral global and local discriminant analysis (S3GLDA) algorithm for hyperspectral image classification was proposed. The method firstly made use of a few labeled samples to preserve the linear separability and global discriminant information of the data set, then the local discriminant information and nonlinear manifold was Keywords：hyperspectral image classification;feature extraction;discriminant analysis;spatial-spectral;semi-supervised learning;spatial neighbors- 101
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Published：2020-07-05 -
A fast and robust method for fundamental matrix estimation
Abstract：In this paper, a new fast and robust fundamental matrix estimation method was proposed to solve the problem that the estimation of fundamental matrix leads to lower estimation accuracy and lower stability due to outliers. The method removed outliers into the computation of the fundamental matrix instead of taking it as an independent processing step. The potential error corresponding points were eliminated by iteration to achieve the stable estimation of the fundamental matrix. Then, the epipolar geometry e Keywords：computer vision;fundamental matrix;epipolar geometry;robustness- 106
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Published：2020-07-05 -
High speed CMOS imaging electronics system for ultraviolet remote sensing instrument
Abstract：For ultraviolet remote sensing instrument, a CMOS spectral imaging system based on the CMOS image sensor GSENSE400 produced by Gpixel company and Virtex-4 FPGA produced by Xilinx company was realized, including driving circuits, bias and the timing control unit. When receiving the high-speed data, the conventional LVDS training method only take into account the random jitter and ignore the sample error caused by deterministic jitter. Therefore, a new training algorithm was established to improve the accurac Keywords：ultraviolet remote sensing instrument;CMOS spectral imaging system;driver circuit;data eye;real-time window monitor- 119
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Published：2020-07-05 -
Mechanism and calibration of non-uniformity for IR polarization imagery obtained with integrated micro-polarizer array
Abstract：For an infrared imaging system integrated with a micro-polarizer array (MPA), DoLP (degree of linear polarization) images are extremely sensitive to non-uniformity. Therefore, large error will occur when the non-uniformity is not calibrated. In order to calibrate the non-uniformity, a polarized-pixel model for optoelectronic conversion process was constructed by taking the incident light as a Stokes vector, and the non-uniformity generation mechanism under the combined effect of a micro-polarizer array (MPA Keywords：infrared polarization imaging;micro-polarizer array;non-uniformity calibration- 91
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Published：2020-07-05 -
Improved SRDCF object tracking via the Best-Buddies Similarity
Abstract：Aiming at the failure of tracking via spatially regularized discriminant correlation filter (SRDCF) algorithm caused by occlusion, scale change and deformation, an improved SRDCF algorithm based on Best-Buddies Similarity was proposed. Firstly, the proposed algorithm based on SRDCF, locating target and estimating scale in the process of object tracking were complemented by using bi-level search strategy. Secondly, a novel robust template matching technique was used to estimate the candidate object position Keywords：object tracking;Best-Buddies Similarity;discriminative correlation filter;spatial regularization- 219
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Published：2020-07-05 -
Rapid calibration for multiple cameras with arbitrary attitude in field space coordinate measurement
Abstract：In view of the complex terrain and the field coordinate measurements in multiple monitoring areas, a rapid calibration method based on the principle of binocular stereo vision for simultaneous calibration of three camera attitude angles and focal length was proposed. This method improved the traditional calibration method, so that it could be used for the situation that the camera focus and attitudes were all unknown, and had low requirement for field environment conditions. It avoided the problem of camera Keywords：binocular vision;camera rapid calibration;arbitrary attitude;large field of view;coordinate measurement- 97
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Published：2020-07-05 -
Noise reduction of independent component analysis based on NLmeans noise prediction
Abstract：It is well known that multiple observed signals are required for image denoising with ICA(Independent Component Analysis). In this paper, a method that multiple observations were generated by making the reduntant imformation of a single image sparse was presented. Firstly, made the only one noisy image to be sparse by using the dictionary compression algorithm of K-SVD (Kernel Singular Value Decomposition). Secondly, obtained the first-time denoised image by using the redundant information. Finally, made bo Keywords：image denoising;BSS;noise prediction;K-SVD;Nlmeans- 95
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Published：2020-07-05
Information Sciences
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