Journals >Laser & Optoelectronics Progress
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2017
Volume: 54 Issue 9
53 Article(s)
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Atmospheric Optics and Oceanic Optics
Simulation on Solar Ground-Layer Adaptive Optics System Based on YAO Software
Liu Sizhen, and Ren Deqing
The observation of solar activity has problems of small field of view and low resolution. The field of view corrected by a single-conjugated adaptive optics system is small, and a multi-conjugated adaptive optics system based on the method of three-dimensional reconstruction is time-consuming and complex. However, a soThe observation of solar activity has problems of small field of view and low resolution. The field of view corrected by a single-conjugated adaptive optics system is small, and a multi-conjugated adaptive optics system based on the method of three-dimensional reconstruction is time-consuming and complex. However, a solar ground-layer adaptive optics system, which corrects ground-layer turbulence, can achieve high efficiency and large field of view, and obtain high-resolution images. In the case of the distribution of four star array and with the average algorithm, the YAO software is used to the numerical simulation of the solar ground-layer adaptive optical system with 40″ and 60″ optimized field of view in J and H bands, and the simulation results are compared with that of single-conjugated adaptive optics system simulation under the same conditions. The results show that Strehl ratio of the ground-layer adaptive optics system increases 130%-210% compared with that of single-conjugated adaptive optics system within imaging field of view of 60″-120″, which is consistent with the results obtained by other softwares in solar adaptive optics..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 90101 (2017)
Application of Wavelet Noise Reduction for Simulated Signals of Imaging Lidar
Sun Guodong, Qin Laian, Cheng Zhi, and Hou Zaihong
One-dimensional lidar signal is achieved by the simulation combining an atmospheric model and the design of parameters of imaging lidar. A two-dimensional light cross image is recovered based on measured beam widths and features of the Gauss distribution. The noised images similar to the real signals detected by imaginOne-dimensional lidar signal is achieved by the simulation combining an atmospheric model and the design of parameters of imaging lidar. A two-dimensional light cross image is recovered based on measured beam widths and features of the Gauss distribution. The noised images similar to the real signals detected by imaging lidar are obtained when we add Gauss white noise with different intensities and certain intensity of average background to the original image. The good de-noising effect is obtained when we denoise the noised lidar light cross image by the two-dimensional wavelet transform method. The relative error between echo signal after denoising and original echo signal is in the range of ±12%. The extinction coefficients of aerosol are retrieved with de-noising lidar signals. Comparing extinction coefficients under the input aerosol atmospheric model with retrieved extinction coefficients of aerosol, we find that the relative error is in the range of ±15% and their variation trends are coincident, which verifies the feasibility of the proposed method using wavelet transform in the de-noising for the noised images of lidar..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 90102 (2017)
Fiber Optics and Optical Communications
High Sensitive Elliptic Side Core Surface Plasmon Resonance Refractive Index Sensing Characteristics Based on Dual-Core Photonic Crystal Fiber
Liang Hongqin, Liu Bin, Chen Jia, Liu Yunfeng, and Hu Jinfeng
A model of refractive index sensing with high sensitivity elliptic side core surface plasmon resonance (SPR) based on dual-core photonic crystal fiber (PCF) is proposed. Properties of a sensor are analyzed by the full vector finite element method with the boundary condition of anisotropic perfectly matched layer. ResulA model of refractive index sensing with high sensitivity elliptic side core surface plasmon resonance (SPR) based on dual-core photonic crystal fiber (PCF) is proposed. Properties of a sensor are analyzed by the full vector finite element method with the boundary condition of anisotropic perfectly matched layer. Results show that SPR can be realized in elliptic side core coated with silver nano-layer, and the resonance peak is highly sensitive to the changing refractive index of inspection hole. Compared with that of the circular structure, the phase matching between the fundamental mode of fiber core and the metal surface plasmon polariton (SPP) mode of the elliptic side core structure is easier to implement. When the ellipticity is 0.7, a sensitivity of 10412 nm·RIU-1 in a refractive index range from 1.45 to 1.50 can be obtained, and the sensing curve has high linearity. In addition, the elliptic side core structure can effectively restrain the high-order SPP mode. The interference introduced by the coupling between fundamental mode and many SPP modes can be avoided..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 90601 (2017)
Fast and High-Precision Position Detection and Calibration for Tilt Mirror
Gao Yinan, Song Yansong, Zhang Lei, Dong Keyan, and Liu Yang
In a single detector compound axis system, the target will be out of field when the principal axis is in an open-loop state and the controlling for input is not proper after starting auxiliary axis tracking. In order to avoid this situation, it is necessary to feedback the accurate position of piezoelectric ceramics (PIn a single detector compound axis system, the target will be out of field when the principal axis is in an open-loop state and the controlling for input is not proper after starting auxiliary axis tracking. In order to avoid this situation, it is necessary to feedback the accurate position of piezoelectric ceramics (PZT) to the principle axis. When the PZT mirror is used independently in an open-loop system, the tilt angle of the PZT mirror cannot be controlled precisely. However, the control accuracy of the system can be greatly improved combined with detection and compensation systems. The detection of target position plays a significant role for mirror controlling, which can provide precise control information for servo system in open-loop state, so that it can ensure the target stay at the center of the optical axis. According to the physical structure characteristics of PZT mirror, the position detecting method for mirror in the single detector compound axis system is studied. The principle of the circuit design is present, and a new calibration method with optical autocollimator is proposed. The control formulas are given, and several repeating experiments are accomplished to verify these control formulas. The results show that the error can be controlled within 20 μrad. The study provides foundation for the design of the control system of single detector compound axis..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 90603 (2017)
Image Processing
Real-Time Pedestrian Reidentification Based on Enhanced Aggregated Channel Features
Huang Xinyu, Xu Jiaolong, Guo Gang, and Zheng Ergong
The pedestrian reidentification is still a challenging problem due to various pedestrian poses, camera viewpoints and illumination conditions etc. Most of the reported works focus on improving the reidentification accuracy without considering the real-time capability. We propose a real-time pedestrian reidentification The pedestrian reidentification is still a challenging problem due to various pedestrian poses, camera viewpoints and illumination conditions etc. Most of the reported works focus on improving the reidentification accuracy without considering the real-time capability. We propose a real-time pedestrian reidentification algorithm based on aggregated channel features (ACF). The ACF is applied to detect the pedestrian candidates, and the extracted ACF features are enhanced with histogram features and texture features and used as a pedestrian reidentification feature descriptor. Finally, based on the enhanced ACF features, we apply the metric learning to train the pedestrian identification model. The experimental results on four datasets show that the proposed feature descriptor obtains the higher recognition accuracy and much faster computation speed compared with the traditional reidentification features. The proposed pedestrian detection and reidentification framework has a running speed of above 10 frame·s-1, and it can basically meet the needs of real-time pedestrian reidentification tasks..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91001 (2017)
Image Matching Algorithm Based on SICA-SIFT and Particle Swarm Optimization
Zhang Xin, Jin Yanxia, and Xue Dan
In view of the problems of large matching calculation amount, too single constraints in the process of matching, and high rate of false matching in the extraction of image feature vector using the existing scale invariant feature transform algorithm, an improved matching algorithm is proposed. Considering the problem oIn view of the problems of large matching calculation amount, too single constraints in the process of matching, and high rate of false matching in the extraction of image feature vector using the existing scale invariant feature transform algorithm, an improved matching algorithm is proposed. Considering the problem of feature description, selective independent component analysis algorithm is adopted to reduce the dimensionality of the feature vector for the decrease of the number and the dimension of the feature vector. In order to solve the problem of higher mismatching rate, a direction constraint is added to the constraint conditions, namely matching twice through the direction of the feature vector and the Euclidean distance to reduce the mismatching rate. The particle swarm algorithm is used to find the extremum of the function to reduce time consumption of the algorithm. The experimental results show that the improved algorithm can effectively increase the matching accuracy..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91002 (2017)
Motion Blur Analysis of Liquid Crystal Display Based on Smooth Pursuit Eye Tracking
Xia Zhenping
To study the motion blur of liquid crystal display more precisely, the smooth pursuit eye tracking with sinusoidal patterns is investigated based on the eye movement tracking apparatus. The experiment tests the smooth pursuit eye tracking using nine kinds of sinusoidal images with different spatial frequencies at four To study the motion blur of liquid crystal display more precisely, the smooth pursuit eye tracking with sinusoidal patterns is investigated based on the eye movement tracking apparatus. The experiment tests the smooth pursuit eye tracking using nine kinds of sinusoidal images with different spatial frequencies at four kinds of motion velocities. The results show that the eye tracking velocity is always a little bit less than the moving velocity of the target image. Besides, the pursuit gain is significantly affected by the target moving velocity. The study puts forward an improved model which can simulate the eye perception results more precisely based on the pursuit gain. Simulation comparison results show that there is obvious difference between the proposed and traditional models when the product of spatial frequency and motion velocity is an integer while there is no big difference in other situations. The investigation results will play a guiding role in the optimization of motion blur and the improvement of visual comfort in liquid crystal displays..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91003 (2017)
Pedestrian Tracking Based on HSV Color Features and Reconstruction by Contributions
Liu Mengfei, Fu Xiaoyan, Shang Yuanyuan, and Ding Hui
It is a challenging task to track pedestrian accurately in complicated environment such as illumination, background variation, occlusion, noise and fast motion. Aiming at these problems, the tracing algorithm based on HSV color features and reconstruction by contributions is proposed. The proposed algorithm extracts thIt is a challenging task to track pedestrian accurately in complicated environment such as illumination, background variation, occlusion, noise and fast motion. Aiming at these problems, the tracing algorithm based on HSV color features and reconstruction by contributions is proposed. The proposed algorithm extracts the mixed color features of target in HSV space to generate the target template set within the particle filter framework. According to the influence of different regions on the tracking results, the contribution of the region is distributed. And it is introduced into the adaptive regularization model, and the region with the minimum reconstruction error is determined as the target to be tracked. In order to be more robust, the templates are updated in real time during the tracking progress. The average center error of tracking results and tracking success rate of 100 sequences tested in OTB are 0.6624 pixel and 0.4153, respectively, and the proposed algorithm has better performance than others. Experimental results show that the proposed algorithm can realize the continuous tracking for pedestrian in complex video scenes and is beneficial to be realized in the practice system with better robustness..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91004 (2017)
Geometric Calibration Data Processing and Software Design of Directional Polarization Camera
Tao Fei, Hong Jin, Song Maoxin, Li Shuang, Tu Bihai, and Wang Yi
Directional polarization camera (DPC) is a space remote sensor with multi-spectrum, multi-angle and multi-polarization data. The procedure of laboratory geometric calibration is complex and it needs to process a large amount of data. By analyzing the principle, model and flow of the DPC laboratory geometric calibrationDirectional polarization camera (DPC) is a space remote sensor with multi-spectrum, multi-angle and multi-polarization data. The procedure of laboratory geometric calibration is complex and it needs to process a large amount of data. By analyzing the principle, model and flow of the DPC laboratory geometric calibration and discussing the demand and framework of the software, we develop a flow-based data-processing software. The software is able to pre-process various calibration test data of the original image and calculate various scaling parameters rapidly. Compared with the manual calculation time of 40 min, the data processing software costs only 50 s. In conclusion, the software can meet the real-time requirement of laboratory calibration..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91005 (2017)
Object Tracking Algorithm Based on Hidden Markov Model and Block Feature Matching
Lu Bing, and Gu Suhang
In the process of moving object tracking, in order to solve the problems that the object is easy to loss because of the occlusion, illumination fluctuation, scale variation and other factors, and the tracking window of the traditional Camshift algorithm is easy to diverge, a moving object tracking algorithm is proposedIn the process of moving object tracking, in order to solve the problems that the object is easy to loss because of the occlusion, illumination fluctuation, scale variation and other factors, and the tracking window of the traditional Camshift algorithm is easy to diverge, a moving object tracking algorithm is proposed based on the fusion of optimized hidden Markov model (HMM) and the block feature matching. Firstly, the principal component analysis (PCA) combined with the feature position is used to reduce the dimension of the affine scale invariant feature transformation (ASIFT) features to generate PCA-ASIFT features which can retain the key information of the object. Then, the of the PCA-ASIFT features can be optimized by using the optimal feature positions of the particle filter. Finally, the object blocks are established by HSV histogram model and the different weights are assigned to different blocks and the integration block features matching, which can improve the Camshift algorithm to accomplish the moving object tracking. The experimental results show that the proposed algorithm can achieve better tracking effect of moving object in natural scenes, and it has bette robustness to occlusion, scale variation and so on..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91006 (2017)
Imaging Systems
Image Distortion Analysis and Correction Study of AOTF Camera Imaging Process
Lü Ze, Chen Youhua, Xue Peng, Wang Zhibin, and Chen Yuanyuan
Aiming at the problem of the imaging distortion caused by the acousto-optic interaction, which is inherent in acousto-optic tunable filter (AOTF), the distortion characteristic of AOTF camera is analyzed by AOTF analytic expressions and geometric aberration formulas. The image distortion model of the acousto-optic inteAiming at the problem of the imaging distortion caused by the acousto-optic interaction, which is inherent in acousto-optic tunable filter (AOTF), the distortion characteristic of AOTF camera is analyzed by AOTF analytic expressions and geometric aberration formulas. The image distortion model of the acousto-optic interaction is established, and the relationship between the distortion coefficient and the incident light propagation angle is showed. The two-step calibration method and the bilinear interpolation method are employed to correct and analyze the distorted image based on the constructed distortion model. The experimental results show that the maximum distortion pixel displacement of the image captured by the no-AOTF camera system is 1.6 pixel, while the maximum distortion pixel displacement of the image captured by the AOTF camera system is 9.0 pixel. The maximum distortion pixel displacement is 1.4 pixel after distortion image is corrected, which is better than the image captured by the no-AOTF camera system. The distortion model is introduced to describe the distortion mechanism and characteristics of AOTF camera. The distortion correction method can solve the problem of image distortion of AOTF camera imaging process effectively, and it has a good application prospect in the accurate measurement of AOTF spectrum camera..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91101 (2017)
Research on Dual-Mode Compound Eye Imaging System
Xu Meng, Wang Yanqin, Wang Changtao, Li Junhui, and Luo Xiangang
The compound eye imaging system, with such advantages as large field of view (FOV), small size, and light weight, has been extensively studied at home and abroad in recent years, and is one of the future development directions of optical imaging technology. Due to the smaller diameter of the sub-aperture, the existing The compound eye imaging system, with such advantages as large field of view (FOV), small size, and light weight, has been extensively studied at home and abroad in recent years, and is one of the future development directions of optical imaging technology. Due to the smaller diameter of the sub-aperture, the existing compound eye system with large FOV is difficult to obtain high resolution images, and therefore cannot meet the requirements in such fields as remote sensing and aerial reconnaissance. To solve these problems, a dual-mode compound eye imaging system is proposed in this paper. This system not only has the imaging capability of multi-aperture and wide FOV as in the conventional compound eye, but also can enhance the imaging resolution significantly while all sub-apertures point at identical direction and the captured sub-images are processed by high resolution reconstruction. The principle and implement method of the system are analyzed. The feasibility of dual-mode imaging is verified by constructing an experimental device, which provides an innovative idea for the development of compound eye imaging system..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91102 (2017)
Radial Eccentricity Error Detection of Primary Mirror of Large Aperture Telescopes
Li Min, Zhang Ang, Zhang Junbo, and Xian Hao
In order to achieve the radial tolerance requirement in the process of machining, coating and aligning of the primary mirror of large aperture telescopes, we present a method based on image processing to realize the real-time detection of the radial eccentricity error of the primary mirror. Using optical imaging systemIn order to achieve the radial tolerance requirement in the process of machining, coating and aligning of the primary mirror of large aperture telescopes, we present a method based on image processing to realize the real-time detection of the radial eccentricity error of the primary mirror. Using optical imaging systems to take pictures of the reference hole which is fixed to the base of the primary mirror support structure and the inner hole of primary mirror while it is moving along the axis, the radial eccentricity error of the primary mirror with respect to the support structure is calculated by the edge extraction and the centroidal algorithm. Experimental results show that this method can realize the real-time measurement of the radial eccentricity error of the primary mirror, and the accuracy satisfies the radial tolerance requirement..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91103 (2017)
Instrumentation, Measurement and Metrology
Influence of Support Deformation on High-Precision Curvature Radius Measurement
Li Zhenxing
When the high-precision measurement of the curvature radius is performed, the measurement error is introduced under three-point support. The theoretical analysis and the finite element simulation of the errors are carried out and the simulation results are verified by experiments. The results show that the rotationallyWhen the high-precision measurement of the curvature radius is performed, the measurement error is introduced under three-point support. The theoretical analysis and the finite element simulation of the errors are carried out and the simulation results are verified by experiments. The results show that the rotationally symmetric error of support deformation leads to the inaccurate radius. The compensation is less than 70 nm under the specific experimental conditions. Based on this, the measurement accuracy can be increased when the measured value of the curvature radius under three-point support is compensated..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91201 (2017)
Real-Time Calibration Technique for Phase Shift Shadow Moiré
Yan Jingjing, and Du Hubing
Phase shift shadow moiré profilometry technique has the characteristics of the high definition and automatic measurement, but it requires the calibration for the measurement sensitivity in advance, and the implementation process is complicated. In order to simplify the calibration process, a calibration technique Phase shift shadow moiré profilometry technique has the characteristics of the high definition and automatic measurement, but it requires the calibration for the measurement sensitivity in advance, and the implementation process is complicated. In order to simplify the calibration process, a calibration technique to measure sensitivity in real time based on three frame fringe patterns is proposed. A grating is shifted with vertical grating plane precisely and three frame phase shift fringe patterns are obtained. The fringe pattern background is removed by the subtraction between different frame fringe patterns. A phase shift algorithm based on the matrix norm is developed to extract the introduced phase shift. Rapid calibration of measurement sensitivity is obtained based on the relationship between phase shift and measurement sensitivity. Experiment results show that the proposed method is simple, flexible and can provide a closed-form solution for the calibration of measurement sensitivity. The calibration precision of the proposed method is better than that of the traditional Dirckx method..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91202 (2017)
Study on Night Vision Compatible Backlight Module of LED Liquid Crystal Display
Zhu Xiangbing, Cui Haitian, Qian Liyong, and Wang Yuanhang
In order to improve the effect of night vision compatible liquid crystal display (LCD), infrared LED is used on top of the RGB three-color LED as the backlight source, and different LEDs are arranged to form two sets of light sources at different modes. According to the brightness and uniformity requirements of the 10.In order to improve the effect of night vision compatible liquid crystal display (LCD), infrared LED is used on top of the RGB three-color LED as the backlight source, and different LEDs are arranged to form two sets of light sources at different modes. According to the brightness and uniformity requirements of the 10.4 in (1 in=2.54 cm) backlight source, backlight is used as a Lambert luminous body to select the type of LED by calculation, to determine the number and arrangement of LED, to select the optical films reasonably, and to design the structure of the backlight module. Because the luminous power of infrared LED is adjustable, in night vision compatible mode, the information can be seen on the LCD screen not only through night vision device but also with naked eyes. Simulation and analysis by TracePro software show that the designed backlight module meets the two requirements of the LCD screen of visible features under the bright light and night vision compatibility..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91203 (2017)
Influences of Different Aberrations on Focusing Performance of Laser Focusing System
Wu Pengfei
Based on optical design software ZEMAX and the Monte Carlo ray tracing method, a comparative study of three design methods of double-reflection focusing system under different angle aberrations are undertaken. And focusing performance parameters on the focusing plane are analyzed. The results show that any slight angleBased on optical design software ZEMAX and the Monte Carlo ray tracing method, a comparative study of three design methods of double-reflection focusing system under different angle aberrations are undertaken. And focusing performance parameters on the focusing plane are analyzed. The results show that any slight angle aberrations can lead to intense deterioration of the focusing performance and large deviation of the focusing location. When there is the angle aberration of the focusing system, different shapes of ignition areas appear for different design methods, which give rise to different flight trajectories and attitudes for the laser thrusters..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91204 (2017)
Lasers and Laser Optics
Temperature Field Simulation of Laser Transmission Welding of Polycarbonate Based on Three-Dimensional Real Surface Topography
Jiang Ning, and Wang Chuanyang
The laser transmission welding process is simulated based on the analysis of the real three-dimensional surface topography. The surface roughness of polycarbonate (PC) sample is measured by using a surface-roughness measuring instrument, the mathematical model of the surface roughness profile is built, and the solid moThe laser transmission welding process is simulated based on the analysis of the real three-dimensional surface topography. The surface roughness of polycarbonate (PC) sample is measured by using a surface-roughness measuring instrument, the mathematical model of the surface roughness profile is built, and the solid modeling is done. The laser welding of smooth surfaces and real rough surfaces are simulated with the software of ANSYS Fluent, and the fracture morphology of the weld is analyzed. The results show that the welding strength of the rough PC surface is lower than that of the smooth surface..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91401 (2017)
Geometric Modeling Methods for Cross-Sectional Profile of Welds in Tailored Blank Laser Welding
Zou Yuanyuan, Zuo Kezhu, Li Pengfei, and Cai Shang
A geometric modeling method for the cross-sectional profile of welds in the tailored blank laser welding is proposed. The edges of the cross-sectional profile are extracted based on the Laws texture filtering and the mathematical morphological closed operation. The curve fitting for these edges of the cross-sectional pA geometric modeling method for the cross-sectional profile of welds in the tailored blank laser welding is proposed. The edges of the cross-sectional profile are extracted based on the Laws texture filtering and the mathematical morphological closed operation. The curve fitting for these edges of the cross-sectional profile are done with the polynomial function model, the exponential function model and the Gaussian function model, respectively. The error analysis of the fitting results is also conducted. The analysis results show that the fitting precision for the upper edge of the cross-sectional profile of welds based on the exponential function model is the highest, however the fitting precision for the lower edge of the cross-sectional profile of welds based on the Gaussian function model is the highest. The geometric modeling experiments for the edges of the cross-sectional profile of welds in the tailored blank laser welding under different welding parameters are carried out and the experimental results demonstrate that the proposed method is effective to realize the geometric modeling for the cross-sectional profile of welds in the tailored blank laser welding..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91402 (2017)
Fabrication of Piezoelectric Ceramic Microstructure Based on Excimer Laser
Li Yigui, Cai Jindong, Huang Yuan, Lü Tong, Yan Ping, and Wang Huan
Plumbum (Pb)-based lanthanum doped zirconate titante piezoelectric ceramic (PZT), silicon (Si) and polydimethylsiloxane (PDMS) are fabricated with 248 nm KrF excimer laser. The processing effects of excimer laser on the above three materials are investigated. To solve the problem that the PZT diaphragm fabricated with Plumbum (Pb)-based lanthanum doped zirconate titante piezoelectric ceramic (PZT), silicon (Si) and polydimethylsiloxane (PDMS) are fabricated with 248 nm KrF excimer laser. The processing effects of excimer laser on the above three materials are investigated. To solve the problem that the PZT diaphragm fabricated with traditional dicing process is fragile, the processing performance of PZT microstructure with excimer laser is investigated. The processing parameters and the relationship among processing parameters, processing depth and processing width of PZT substrate are obtained when we adjust several parameters of excimer laser, such as laser pulse energy, pulse frequency, scanning speed and scanning times. Effects of auxiliary gas on the PZT surface roughness processed with excimer laser are studied. The PZT-Si cantilever and PZT-Si diaphragm are fabricated with excimer laser, and their piezoelectric properties are tested. Results show that the two PZT micro-piezoelectric structures fabricated by excimer laser have excellent piezoelectric performance, and the structures can be used as key devices of micro-piezoelectric actuator. The feasibility of processing PZT microstructure with excimer laser is proved..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91403 (2017)
Laser Tube Asymptotic Bending Correction Process Based on Layer Scanning
Li Pin, and Yan Zhang
The laser tube asymptotic bending correction is realized by the layer scanning. Based on the Perona-Malik edge extraction algorithm and the RANSAC linear feature extraction algorithm, the real-time online measurement of the laser asymptotic bending correction process is realized. The influences of process parameters onThe laser tube asymptotic bending correction is realized by the layer scanning. Based on the Perona-Malik edge extraction algorithm and the RANSAC linear feature extraction algorithm, the real-time online measurement of the laser asymptotic bending correction process is realized. The influences of process parameters on the pipe bending angles are analyzed. The results show that the bending angle nearly increases with time linearly. The position and shape parameters have little effect on the increasing rate of bending angles, while the axial feeding times are directly proportional to the variation of the single-layer bending angle. The curvature of the bending section can be changed by the axial feeding step length. The higher the average laser power, the faster the increasing rate of bending angles..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91404 (2017)
Selective Laser Sintering Process of Coated Sands
Bo Fuxiang, He Bing, and Zong Xuemei
Based on the selective laser sintering (SLS) technique, the influences of the process parameters including scanning speed, laser power, layer thickness, scanning spacing, and preheating temperature on the strength and dimensional precision of SLS prototype parts are analyzed under different process parameter combinatioBased on the selective laser sintering (SLS) technique, the influences of the process parameters including scanning speed, laser power, layer thickness, scanning spacing, and preheating temperature on the strength and dimensional precision of SLS prototype parts are analyzed under different process parameter combinations. The study results show that, all the sintering process parameters can affect the sintering strength and dimensional precision of prototype parts, and there exist interactions between various factors. When the laser power is 40 W, the scanning speed is 2500 mm·s-1, the scanning spacing is 0.15 mm, the layer thickness is 0.20 mm, and the preheating temperature is 60 ℃, the optimal sintering strength and dimensional precision can be obtained. Based on these results, by combining the traditional sand casting method, a new advanced-construction-machinery hydraulic valve is rapidly casted, which verifies the feasibility of rapid casting process of hydraulic components based on the SLS process..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91405 (2017)
Super-Hydrophobic Micro-Nano Structures on Aluminum Surface Induced by Nanosecond Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and Peter Bennett
One method to fabricate super-hydrophobic aluminum surfaces by using nanosecond fiber lasers is proposed. After the laser-processed samples are baked, a series of aluminum surfaces with different wetting properties are obtained. A super-hydrophobic surface can be obtained by increasing the laser fluence. The study resuOne method to fabricate super-hydrophobic aluminum surfaces by using nanosecond fiber lasers is proposed. After the laser-processed samples are baked, a series of aluminum surfaces with different wetting properties are obtained. A super-hydrophobic surface can be obtained by increasing the laser fluence. The study results show that, with the increase of laser fluence, not only the aluminum surface roughness increases, but also a clear micro-nano two-level structure is formatted. The area ratio between air and the total area of the super-hydrophobic aluminum composite contact surface is 90%. The super-hydrophobic surface induced by nanosecond laser is attributed to the coaction of micro-nano structures and chemical compositions..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91406 (2017)
Study on 532-nm Flattened Laser Beam for Silicon Wafer Grooving
Li Haiou, Wei Chunrong, Wang Xiaofeng, Zhang Zichen, and Pan Lingfeng
According to the diffraction principle, a flattened shaping element is designed and prepared, which converts a Gaussian distribution of laser energy to a flat-top distribution. The laser dicing test of silicon wafers is carried out by using the 532 nm pulsed laser and the influences of laser energy, dicing speed and foAccording to the diffraction principle, a flattened shaping element is designed and prepared, which converts a Gaussian distribution of laser energy to a flat-top distribution. The laser dicing test of silicon wafers is carried out by using the 532 nm pulsed laser and the influences of laser energy, dicing speed and focusing position on the wafer cutting effect are investigated. The results show that based on the laser dicing by flattened beams, a groove with a width of about 16 μm and a depth of about 18 μm can be obtained, whose bottom is flat and wall is steep. In addition, the heat affected zone under the flattened beam is obviously smaller than that under the Gaussian beam..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91407 (2017)
Application of Two-Lens Slit Spatial Filter in High Power Lasers
Xiong Han
Utilizing some parameters of national ignition facility (NIF), the two-lens slit spatial filter (SSF) replaces the pinhole spatial filter in main amplifier cavity for the high-power laser facility, and the application is studied preliminarily. Take NIF as an example, the far-field intensity decreases two orders of magnUtilizing some parameters of national ignition facility (NIF), the two-lens slit spatial filter (SSF) replaces the pinhole spatial filter in main amplifier cavity for the high-power laser facility, and the application is studied preliminarily. Take NIF as an example, the far-field intensity decreases two orders of magnitude due to the SSF, reducing the cavity spatial filter and the amplifier cavity by about 6.2450 m (27%) and 13.8707 m (30%) respectively. Basically there will be no pinhole (slit) closure problem in the main optical system since the reduction of far-field intensity and the absences of filter aperture in transport spatial filter. Additionally, based on the design of off-axis angle complanation combined with the characteristics of mutual imaging between the distorted mirror and the reflector in amplifier cavity, the off-axis multi-pass of cavity spatial filter composed with SSF is designed to avoid the amplified spontaneous emission, which lays the foundation for the practical application of SSF and the further development of high power lasers..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91408 (2017)
Research on Technology of Field Installation for Amplifier Optomechanical Components of NIF
Liu Xiaobo, Wei Xiaofeng, Yuan Xiaodong, Ni Wei, and Fan Naiji
Based on American National Ignition Facility (NIF), the spatial layout and structural features of optomechanical components of Nd∶glass laser amplifier are introduced. The field installation equipment and installation process parameters of optomechanical components are dissected. The field installation technologies areBased on American National Ignition Facility (NIF), the spatial layout and structural features of optomechanical components of Nd∶glass laser amplifier are introduced. The field installation equipment and installation process parameters of optomechanical components are dissected. The field installation technologies are studied, such as accurate alignment and rigid connection, guide rail escort during convey, grading lift based on CCD detection and flexible docking. At the same time, the situation of field installation of optomechanical components for similar facility in China is summarized. The results of this study are intended to provide technical support for China′s upcoming large-scale laser-driven inertial confinement fusion facility..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91409 (2017)
Machine Vision
Deep Learning Model Design of Video Target Tracking Based on TensorFlow Platform
Liu Fan, Liu Pengyuan, Li Bing, and Xu Binbin
Due to the complexity of training model and huge training set of deep learning, the development of deep learning is seriously hindered. We use an open-source platform called TensorFlow developed by Google to build deep learning model for video object recognition and tracking. Some basic theories are introduced includinDue to the complexity of training model and huge training set of deep learning, the development of deep learning is seriously hindered. We use an open-source platform called TensorFlow developed by Google to build deep learning model for video object recognition and tracking. Some basic theories are introduced including the principles of deep learning and TensorFlow′s properties. The framework of deep learning model developed by TensorFlow is outlined. Experiments are designed based on the standard data in VOT2015. Experimental results show that the model has high computational efficiency and recognition accuracy, and it can adjust network structure easily, find optimal structural model fast and complete video object recognition and tracking task well..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91501 (2017)
Camera Calibration with Narrow Field of View for Deep Space
Zhao Min, Zheng Xingchun, Huang Qiuhong, and Zhu Lingjian
Aiming at the calibration of camera with a narrow field of view for deep space, the simulation analysis method based on stereo target is built. The spatial distribution influence of the target points on the accuracy of camera calibration is analyzed thoroughly. The number and position distribution of the target points Aiming at the calibration of camera with a narrow field of view for deep space, the simulation analysis method based on stereo target is built. The spatial distribution influence of the target points on the accuracy of camera calibration is analyzed thoroughly. The number and position distribution of the target points are reasonably designed before camera calibration. The results show that spatial distribution scope of the target points has the greatest influence on the calibration accuracy while the number of target points has little influence. The calibration accuracy can be enhanced by arranging target points from the nearest measuring distance. A center location algorithm combining the region of interest with sub-pixel edge detection by the gray moment is proposed to locate the image target spot. The location accuracy and the processing efficiency of the image algorithm are improved effectively. The virtual stereo target is arranged to calibrate the intrinsic parameter of a camera quickly. The calibration precision is high and the method has practical application value. This method is also applicable to camera calibration without target stitching..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91502 (2017)
Image Comparison and Analysis of Trouble of Moving EMU
Lu Shengfang, and Liu Zhen
The trouble of moving electric multiple-unite (EMU) detection system (TEDS), can monitor comprehensively the status of China railway high-speed (CRH) train, by using the high-speed linear cameras located besides the railway. We fulfill the automatic identification and inspection of the target in the high-quality image The trouble of moving electric multiple-unite (EMU) detection system (TEDS), can monitor comprehensively the status of China railway high-speed (CRH) train, by using the high-speed linear cameras located besides the railway. We fulfill the automatic identification and inspection of the target in the high-quality image by using the machine learning and pattern recognition technology. However, the image taken by the linear camera is susceptible to the speed of vehicle, and there is a geometric deformation in the horizontal direction of image, which brings difficulties to the automatic recognition and detection of the subsequent target. To solve this problem, we set up a set of reference images, register and re-divide the images obtained in other time, according to the corresponding reference image, so as to minimize the influence of train′s speed on imaging deformation. Combined with TEDS, we use multi-resolution image fast registration method to achieve the rapid segmentation and alignment of subsequent target images. Hence, we propose an improved image subtraction technique, in order to quickly and automatically locate and detect the fault region by comparing and analyzing the aligned image pairs..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91503 (2017)
Visual Target Tracking Algorithm Based on Image Signature Algorithm
Zhang Bo, and Long Hui
Aiming at the problems of fast motion, scale variation, deformation and occlusion in visual target tracking algorithms, the visual target tracking algorithm based on image signature algorithm is proposed. The proposed algorithm is based on the correlation filtering algorithm. The target appearance model is constructed Aiming at the problems of fast motion, scale variation, deformation and occlusion in visual target tracking algorithms, the visual target tracking algorithm based on image signature algorithm is proposed. The proposed algorithm is based on the correlation filtering algorithm. The target appearance model is constructed with various features, and the precision and robustness of the proposed algorithm are improved. In order to solve the target relocation problem under the condition of severe occlusion, the image signature algorithm is used to calculate image sparse salient regions and to obtain the position of candidate target. The candidate target is re-ranked by the classifier, and the target is relocated. Scale pool strategy and adaptive model updating strategy are used to solve the problems of scale variation and tracking drift in tracking. Standard data sets are used to test the performance of the proposed algorithm, and the results show that the proposed algorithm is superior to traditional correlation filtering algorithms in terms of tracking success rate and precision. The proposed algorithm can solve the target tracking problems under the conditions of fast motion, scale variation, deformation and occlusion..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91504 (2017)
Materials
Influence of Annealing Temperature on Properties of Cu2ZnSnS4 Thin Films Prepared by Step Sputtering
Zhao Qichen, Hao Ruiting, Liu Sijia, Yang Min, Lu Yilei, Liu Xinxing, and Chang Faran
Cu2ZnSnS4 (CZTS) thin films are prepared by the step sputtering with three binary-sulfide compound targets of ZnS, SnS, CuS. The annealing is carried out at different temperatures. The influences of annealing temperature on crystal structure, element composition, surface morphology and optical characteristics of CZTS tCu2ZnSnS4 (CZTS) thin films are prepared by the step sputtering with three binary-sulfide compound targets of ZnS, SnS, CuS. The annealing is carried out at different temperatures. The influences of annealing temperature on crystal structure, element composition, surface morphology and optical characteristics of CZTS thin films are investigated. The results show that the secondary phases like Cu2S and SnS are found in the CZTS thin films at the annealing temperature of 400 ℃. With the increase of the annealing temperature, the variety of the secondary phases decreases. When the annealing temperature is 550 ℃, the thin film surface is smooth and compact and the variety of the secondary phases is the least. However, when the annealing temperature is 600 ℃, the film surface becomes rough and the variety of the secondary phases increases..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91601 (2017)
Novel Structure Design of Left-Handed Material with Broadband and Low Loss
Shen Chunchun, Li Minquan, Zhou Yongguang, Li Xuanxuan, Wang Shandong, and Pan Xu
Based on the theory of resonant-type left-handed materials, a novel structural unit of left-handed materials with broadband and low loss is proposed. By using the Nicolson-Ross-Weir algorithm and the Ansoft HFSS software, the equivalent permittivity, the equivalent permeability and the equivalent refractive index of thBased on the theory of resonant-type left-handed materials, a novel structural unit of left-handed materials with broadband and low loss is proposed. By using the Nicolson-Ross-Weir algorithm and the Ansoft HFSS software, the equivalent permittivity, the equivalent permeability and the equivalent refractive index of the structural unit are obtained. The results show that the proposed structural unit has a low loss characteristic. In the frequency range of 23-32.3 GHz, both the equivalent permittivity and the equivalent permeability of the proposed structural unit are negative, meanwhile, the real part of the equivalent refractive index is negative while the imaginary part is close to zero. The proposed structural unit can provide a certain reference for the design and application of left-handed materials in the Kα band..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91602 (2017)
Nonlinear Optics
Analysis of Output Characteristics of Intracavity-Frequency-Doubled Singly Resonant Optical Parametric Oscillator
Li Peng, Gao Xiaoxia, and Gu Yuzong
The threshold and stable operation of a continuous-wave singly resonant optical parametric oscillator (SRO) are closely related with the roundtrip loss of the resonant signal travelling in the resonant cavity. Under the plane-wave approximation, a theoretical model considering the linear absorption of the nonlinear cryThe threshold and stable operation of a continuous-wave singly resonant optical parametric oscillator (SRO) are closely related with the roundtrip loss of the resonant signal travelling in the resonant cavity. Under the plane-wave approximation, a theoretical model considering the linear absorption of the nonlinear crystal and the nonlinear loss introduced by intracavity-frequency-doubled (IFD) is proposed to describe the output characteristics of continuous-wave IFD-SRO. The analytical solution is also given. The theoretical calculation results are in good agreement with the experimental results. According to these results, the output characteristics of the 532 nm green laser pumped IFD-SRO with resonant signal at 780 nm and the 1064 nm infrared laser pumped IFD-SRO with resonant signal at 1560 nm are predicted. The model is simple and easy to calculate. It provides a guideline for optimizing the design of continuous-wave IFD-SRO..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 91901 (2017)
Optical Devices
Fourier Transform of 2D Moiré Fringe
Yang Xiaoming, Zheng Sanchao, Huang Gaokun, and Zhou Sumei
The Fourier principles of moiré fringes produced by the square aperture planar microlens array and micrographics array are studied. The square aperture planar microlens array is regarded as orthometric 2D grid lines. The analytic formula of Fourier transform for 2D moiré fringes of the square aperture planar The Fourier principles of moiré fringes produced by the square aperture planar microlens array and micrographics array are studied. The square aperture planar microlens array is regarded as orthometric 2D grid lines. The analytic formula of Fourier transform for 2D moiré fringes of the square aperture planar microlens array is derived based on the principle of Fourier transform of 1D grating moiré fringe. Moreover, the low frequency (1, -1) moiré fringe is analyzed in detail. The period and synchronization of moiré fringe with different angles are studied as key point. The experiments are carried out by using the 2D grid templates and micrographics arrays with different structural parameters. The results show that the experimental values agree well with the theoretical values, which provides theoretical basis for the application and research of the square aperture planar microlens array..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 92302 (2017)
Design and Experiment of LED Cylindric Sunflower Radiator
Tang Fan, and Guo Zhenning
In order to improve the cooling capacity of light emitting diode (LED), based on the principle of the chimney effect, the cylinder is added to traditional sunflower radiator to form a special chimney structure. We build a three-dimensional model by adopting Solidworks, and use its plug called Flow Simulation to simulatIn order to improve the cooling capacity of light emitting diode (LED), based on the principle of the chimney effect, the cylinder is added to traditional sunflower radiator to form a special chimney structure. We build a three-dimensional model by adopting Solidworks, and use its plug called Flow Simulation to simulate the model. The model with the number of fins of 12, the maximum diameter of 70 mm and the hight of radiator of 40 mm is optimized. Studies have shown when the number of fins is 20, the maximum diameter is 85 mm and the hight of radiator is 65 mm, LED cylindric sunflower radiator have the best cooling capacity. At the moment, the optimized highest temperature of LED is 48.98 ℃, which is reduced by 13.05 ℃. The temperature of the LED can meet the security requirements when the power of the LED chips are 8, 12, 16, 19 W. The LED radiator sample with the power of 8 W is experimentally tested. The results show that the average error between the actual temperature of the 4 monitoring points and the simulated temperature is 4.8%, which is within the allowable range. It confirms the correctness of the simulation steps. When the power is 32 W, the highest temperature of the LED chips still meet the technical requirements of less than 125 ℃. Which is 6.44 ℃ lower than that of the traditional sunflower radiator. In conclusion, the designed LED cylindric sunflower radiator can provide a new way to solve the heat dissipation problem of high power LED..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 92303 (2017)
Physical Optics
Research on Spatial Coherence of Light Source Based on Matlab Simulation Algorithm
Wang Fan, Zhang Yongan, Yang Sheng, Guo Yinchu, and Zhang Yaping
The influence of spatial coherence of light source on interference is explored on the basis of Young′s double-slit experiment. Firstly, the spatial broadening problem of light source is equivalent to the problem of double-slit with width illuminated by parallel light. Then the double-slit is approximated to multiple seThe influence of spatial coherence of light source on interference is explored on the basis of Young′s double-slit experiment. Firstly, the spatial broadening problem of light source is equivalent to the problem of double-slit with width illuminated by parallel light. Then the double-slit is approximated to multiple secondary light source point arrays with discretization in which the distance of adjacent points is extremely tiny. An algorithm is deduced based on the principle of wave vector superposition. In this algorithm, each pair of secondary light source points in double-slit is designed as an interference unit. The interference light intensity for each unit at each observation spot of view plane is calculated, respectively. Then, the interference intensity of all the units is linearly superimposed, and the total light intensity of the observation point is calculated. Finally, we use Matlab to simulate the light intensity distribution when the double-slit is vertically illuminated by monochromatic parallel light, Gauss spectrum and rectangle spectrum with different slit widths, respectively. Comparison of simulated results shows that the influence of the double-slit broadening on stripe contrast is much greater than that of the spectrum broadening. The proposed algorithm simplifies computed process and raises program operating speed remarkably..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 92601 (2017)
Quantum Optics
Exact Solutions of Energy Spectrum and Quantum Entanglement in Tavis-Cummings Model
Cong Honglu, and Ren Xuezao
The energy spectrum and the quantum entanglement in the Tavis-Cummings model are exactly solved, without the rotating wave approximation, and this exact solution of the energy spectrum is compared with the result under the rotating wave approximation. The influences of the atom state parameter θ and the atom-field coupThe energy spectrum and the quantum entanglement in the Tavis-Cummings model are exactly solved, without the rotating wave approximation, and this exact solution of the energy spectrum is compared with the result under the rotating wave approximation. The influences of the atom state parameter θ and the atom-field coupling intensity at the initial time on the quantum entanglement are discussed. The results show that, when the coupling intensity is relatively weak, the energy spectrum under the rotating wave approximation is consistent with the exact solution. When the coupling intensity is relatively strong, there exist obvious differences between them. With the increase of θ, the entanglement degree increases gradually. With the increase of the coupling intensity, the phenomenon of entanglement sudden death between two atoms occurs. Moreover, the first occurrence time of entanglement sudden death becomes short and the duration of the entanglement death increases gradually..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 92701 (2017)
Remote Sensing and Sensors
Impacts of Different Factors on Accuracy of Point Cloud Obtained from Terrestrial Three-Dimensional Laser Scanning
Cai Yue, Xu Wenbing, Liang Dan, Li Chong, and Chen Zuo
Many factors affect the accuracy of the point cloud obtained from terrestrial three-dimentional laser scanning. These factors exist together and influence each other. Therefore, it is useful to effectively improve the accuracy of the point cloud by studying the effect of each factor and their interaction on the number,Many factors affect the accuracy of the point cloud obtained from terrestrial three-dimentional laser scanning. These factors exist together and influence each other. Therefore, it is useful to effectively improve the accuracy of the point cloud by studying the effect of each factor and their interaction on the number, reflection intensity and standard deviation of point cloud. Set the target color, roughness and distance as the study objects. By using multi-factor variance analysis method and multiple linear regression method, the significance of the influence of the various factors and their interactions are analyzed, and regression equations between the standard deviation and reflection intensity of point cloud are fitted. Results show that distance of target object has a significant impact on the number of point cloud. The number of point cloud at 5 m is about forty times as much as the number at 30 m. Distance is inversely proportional to the number of point cloud. Color of target object has a significant impact on the reflection intensity of point cloud. The strongest reflection intensity of point cloud for white is 0.54, and the one for black is 0.18. The reflection intensity of point cloud from strongest to weakest is white, green, blue, red, black. Distance of the target object has greatest impact on the standard deviation of point cloud obtained from terrestrial three-dimensional laser scanning. The standard deviation of point cloud at 30 m is three times as much as the value at 5 m. And color is taken the second place, however the effect of the roughness is not obvious. There is a power function relation between the standard deviation and reflection intensity of point cloud..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 92801 (2017)
Low Resolution Metering Guide for High Resolution Imaging Adaptive Exposure
Cao Qilei, Dong Lili, Zhao Ming, and Xu Wenhai
At present, the space remote sensing camera still can not obtain the scene spectral radiance information in advance, so it can not adjust the exposure parameters according to the scene content. To this end, a method for adaptively configuring exposure parameters is proposed, which is realized by metering, calculating aAt present, the space remote sensing camera still can not obtain the scene spectral radiance information in advance, so it can not adjust the exposure parameters according to the scene content. To this end, a method for adaptively configuring exposure parameters is proposed, which is realized by metering, calculating and imaging. In order to reduce the influence of metering camera on space remote sensing camera weight in practical application, the paper presents the application of a large-scale metering camera for metering, and a method of high resolution imaging based on low resolution image is proposed. Firstly, the change rule between the statistical characteristics of exposure of typical scenes and the scale. Large-scale metering image is used to conduct scale merging, and the exposure time of each scale is calculated. The function relationship between scale and exposure time is established by polynomial fitting, and the exposure parameters corresponding to the original scale are determined, so as to realize the imaging of space remote sensing camera with large-scale metering camera. According to the statistical results of unmanned aerial vehicle, the method can be applied to several typical scenes, the exposure parameter error between the value determined by large-scale fitting and the value determined by original scale image is less than 4%. Satellite picture data show that the error between the exposure parameters determined by large-scale fitting and the exposure parameters determined by the original scale image is less than 6% when the metering scale ratio is more than 90 times, but it still can accurately guide high-resolution camera imaging..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 92802 (2017)
Segmentation of High-Resolution Remote Sensing Image Combining Phase Consistency with Watershed Transformation
Chen Yang, Fan Rongshuang, Wang Jingxue, and Wu Zenglin
In consideration of the problem of over-segmentation or under-segmentation in high-resolution remote sensing image segmentation that the noise leads to, a high-resolution image segmentation method with phase consistency and watershed transformation is proposed. Firstly, the phase-consistent model method with spectral sIn consideration of the problem of over-segmentation or under-segmentation in high-resolution remote sensing image segmentation that the noise leads to, a high-resolution image segmentation method with phase consistency and watershed transformation is proposed. Firstly, the phase-consistent model method with spectral similarity is adopted to obtain the edge response amplitude, and then the automatic marker watershed algorithm is adopted to segment the image. Based on the multiple restrictions for the features, such as spatial position, shape and area of adjacent segmentation objects, adjacent segmentation object merging cost function model is proposed to optimize the segmentation result and obtain the final segmentation result. Experimental images of the typical area are selected for the segmentation experiment. The effectiveness of the proposed method is verified by visual evaluation, supervision evaluation and comparison with the typical segmentation methods..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 92803 (2017)
Reviews
Progress in Detection of Circulating Tumor Cell by in vivo Photoacoustic Flow Cytometry
Yang Ping, Wei Dan, Pang Kai, Wang Qiyan, Zhou Quanyu, and Wei Xunbin
Tumor is a great threat to human health, the majority of tumor patients die from metastatic tumor rather than primary tumor. Circulating tumor cell (CTC) is an important indication of metastatic tumor, and its detection can be used for monitoring tumor metastasis and prognosis evaluation. Based on the difference of ligTumor is a great threat to human health, the majority of tumor patients die from metastatic tumor rather than primary tumor. Circulating tumor cell (CTC) is an important indication of metastatic tumor, and its detection can be used for monitoring tumor metastasis and prognosis evaluation. Based on the difference of light absorption between CTC and blood background, in vivo photoacoustic flow cytometry (PAFC) can realize CTC in vivo detection. Compared with the traditional CTC detection methods, the advantage of PAFC is that it can detect the number of CTC in the circulatory system, and the detection is noninvasive and high sensitive. This review summarizes the methods of the real-time and label-free detection of melanoma CTC and the real-time detection of breast cancer by nanoparticle targeting, and their application in evaluation of tumor metastasis and treatment effect..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 90001 (2017)
Research Status of Optofluidic Variable Aperture
Lü Hongyan, Cui Jianguo, Liu Shengxiong, Sun Zhongjie, Pu Shanshan, and Xie Liang
Optofluidic variable aperture has important application potential in image acquisition, target tracking, biological recognition and other portable electronic devices. Comparing with the mechanical aperture, the aperture is almost perfectly adjustable circle, and it has some advantages such as easy to process, compact sOptofluidic variable aperture has important application potential in image acquisition, target tracking, biological recognition and other portable electronic devices. Comparing with the mechanical aperture, the aperture is almost perfectly adjustable circle, and it has some advantages such as easy to process, compact structure, convenient driving and low power consumption, etc. So it has become one of the hot spots in the field of micro-nano optical research at present. This paper summarizes the development status of the existing optofluidic variable aperture technology at home and abroad, and looks forward to the future development direction of optofluidic variable aperture by summarizing the previous research methods..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 90002 (2017)
Research Progress on Adaptive Wide-Field Microscopic Imaging Technology with High Resolution
Xu Yang, Man Tianlong, and Wan Yuhong
Optical microscopic imaging technology makes it possible to observe the fine structure of tiny samples. However, in the field of microscopic imaging of biological samples, the aberration makes the imaging quality of any microscopic imaging technology unable to achieve the theoretical expectation. For the purpose of impOptical microscopic imaging technology makes it possible to observe the fine structure of tiny samples. However, in the field of microscopic imaging of biological samples, the aberration makes the imaging quality of any microscopic imaging technology unable to achieve the theoretical expectation. For the purpose of improving imaging quality, adaptive optics technology is applied to different types of microscopic imaging systems for aberration detection and correction. In this study, the research of adaptive wide-field microscopy imaging system is illustrated in detail. Furthermore, we demonstrate the characteristics, advantages and existing problems of the digital holography and incoherent digital holography adaptive optics technologies..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 90003 (2017)
Application and Progress of Laser Shaping Devices in Optical Tweezers
Guo Zhihe, Liu Zetian, Chen Qimin, Huang Haojie, and Ren Hongliang
Optical tweezer is an important technique that utilizes the interaction between momentum of light and matter to produce light potentials and then realize particle trapping. Optical tweezer is widely used in the field of nano- or micron-scale particle capture and manipulation. The development of today′s technology and dOptical tweezer is an important technique that utilizes the interaction between momentum of light and matter to produce light potentials and then realize particle trapping. Optical tweezer is widely used in the field of nano- or micron-scale particle capture and manipulation. The development of today′s technology and demands puts forward higher requirements for beam transformation of optical tweezers. Therefore, it is necessary to shape the light beam to obtain the required light field distribution of the optical tweezers. We follow laser beam shaping devices, and the applications of prism, diffractive optical elements, spatial light modulators, digital micro-mirror devices, optical fibers and other optical components in the optical tweezer system are introduced. Typical shaping optical paths of these devices are listed, and recent advances in beam shaping of these devices are presented. Characteristics of the methods mentioned above and their corresponding capture abilities in the shaping design of the capture light source are introduced as well..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 90004 (2017)
High Power Laser and Its Development
Wang Shiling, and Fang Fengzhou
High power lasers are widely used in the various areas such as industry and defense. They are essential components of modern laser in material processing, laser remanufacturing and defense security. With the development of laser technology, high power lasers have made much progress. Many new types of lasers are appeareHigh power lasers are widely used in the various areas such as industry and defense. They are essential components of modern laser in material processing, laser remanufacturing and defense security. With the development of laser technology, high power lasers have made much progress. Many new types of lasers are appeared in recent years. Compared with the traditional lamp pumped lasers, the semiconductor lasers play a more and more important role in the development of economy because of smaller sizes, higher efficiency, less weight, longer lifespan and lower cost. The characteristics and development of semiconductor lasers and all solid-state or not all solid-state semiconductor pumped by semiconductor lasers are summarized in details. The improvements on performance of high power semiconductor lasers, the development trend of high power laser diode and applications in intelligent manufacturing technology in the future are also discussed..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 90005 (2017)
Research Progress on High Birefringence Terahertz Photonic Crystal Fibers
Liu Mengnan, Li Mengxue, Jiang Chengyi, Yan Xu, and Wan Yong
With the development of terahertz techniques, terahertz waveguides have gradually become one of the research hotspots. Compared to the terahertz polymer waveguide, the terahertz photonic crystal fiber (PCF) has obvious advantages in the aspect of high birefringence. Based on the introduction of the research status of tWith the development of terahertz techniques, terahertz waveguides have gradually become one of the research hotspots. Compared to the terahertz polymer waveguide, the terahertz photonic crystal fiber (PCF) has obvious advantages in the aspect of high birefringence. Based on the introduction of the research status of traditional terahertz waveguide techniques, the high birefringence terahertz PCFs with different principles and different structures are mainly analyzed and summarized, and their advantages and disadvantages are compared. In addition, the application status and the future work directions of high birefringence terahertz PCFs are summarized and prospected..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 90006 (2017)
Research Progress of Perfect Vortex Field
Wang Yajun, Li Xinzhong, Li Hehe, Wang Jingge, Tang Miaomiao, Tang Jie, Wang Yishan, and Nie Zhaogang
The perfect vortex (PV) field has the advantage that the radius of bright ring does not change with the topological charge. The PV field has importance application value in the fields of micro-particle manipulation and quantum communication, and it is a research hotspot in the field of light field modulation in recent The perfect vortex (PV) field has the advantage that the radius of bright ring does not change with the topological charge. The PV field has importance application value in the fields of micro-particle manipulation and quantum communication, and it is a research hotspot in the field of light field modulation in recent years. Three typical methods of generating PV field are introduced. Moreover, the modulation techniques and characterization of PV field are summarized and the applications of PV field are reviewed..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 90007 (2017)
Fiber-Optic Surface Plasmon Resonance Sensing Technology
Wang Wenhua, Xiong Zhengye, Shi Wenqing, Huang Jiang, Tian Xiuyun, Fei Xianxiang, and Xie Yuping
Fiber-optic surface plasmon resonance (SPR) sensing is one of the research focuses in fiber-optic sensing filed. Various structures and merits of fiber-optic SPR sensors are discussed in detail, and influences of material and thickness of the metal film, the length of the coated optical fiber, the combination and the tFiber-optic surface plasmon resonance (SPR) sensing is one of the research focuses in fiber-optic sensing filed. Various structures and merits of fiber-optic SPR sensors are discussed in detail, and influences of material and thickness of the metal film, the length of the coated optical fiber, the combination and the thickness ratio of double-layer metal film on the performance of fiber-optic SPR sensors are analyzed. Research progresses and applications of fiber-optic SPR sensors are summarized, including multi-mode fiber-optic SPR sensors, single-mode fiber-optic SPR sensors, fiber Bragg grating SPR sensors, tilt fiber grating SPR sensors, long-period fiber grating SPR sensors, multi-channel fiber-optic SPR sensors, photonic crystal fiber-optic SPR sensors and nano-metal-particle fiber-optic SPR sensors. Research emphasis and development direction of fiber-optic SPR sensors are given..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 90008 (2017)
Scattering
Aerosol Concentration Measurement Based on Near-Forward Light Scattering Method
Ma Ying, Wang Longjiang, Yu Jie, Wang Kunjun, Yin Wangbao, and Dong Lei
Based on the near-forward light scattering method, the polydispersion sub-micron aerosol concentration measurement is realized. The tungsten halogen lamp is employed as the light source in the measurement device. The shaped annular beam is converged to the gas to be measured. After being collected by a lens, the scatteBased on the near-forward light scattering method, the polydispersion sub-micron aerosol concentration measurement is realized. The tungsten halogen lamp is employed as the light source in the measurement device. The shaped annular beam is converged to the gas to be measured. After being collected by a lens, the scattering light is detected by a photodetector. The aerosol concentration is inversed by analyzing the intensity variation of the detected light. The experimental results show that the detection sensitivity of the measurement method can reach to 10-4 μg·L-1 and the linear response range covers 6 orders of magnitude. This mothod can be applied to the fields of nuclear industry, medicine, microelectronics, and so on..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 92901 (2017)
Spectroscopy
Near Infrared Spectral Pre-Processing Algorithm Based on Histogram Layering Mapping
Wang Lijie, Yang Yuyi, Dai Min, and Gao Wei
In order to solve the pre-processing problem of spectral data in near infrared rapid detection analysis of content of milk components, a pre-processing algorithm for score resetting (SR) of principal components (PC) in the near infrared spectrum on the basis of histogram layering mapping technology is proposed. With glIn order to solve the pre-processing problem of spectral data in near infrared rapid detection analysis of content of milk components, a pre-processing algorithm for score resetting (SR) of principal components (PC) in the near infrared spectrum on the basis of histogram layering mapping technology is proposed. With glucose content in the three components samples consisting of glucose, NaCl and water, and lactose content in the fresh milk samples, as the detecting objects, cumulative contribution rates of the near infrared scattering spectral PC scores are pre-processed by means of mapping by layer and by piece. Furthermore, partial least squares (PLS) regression analysis method is used for modeling, thereby test and analysis of sugar content information in corresponding near infrared spectra are completed. The results show that after SR pretreatment, the predicted deviation of the calibration curve of the milk lactose content PLS model is reduced by 23.9%, the actual prediction deviation is reduced by 27.8%, and the actual prediction deviation of the verification set is reduced by 16.7%. This SR spectral preprocessing method takes into account multi-scale information such as spectra, reference content value and component correlation to realize spectral information denoising enhancement. Therefore, false deletion of useful information can be avoided, and inadequate fitting and overfitting can be prevented..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 93001 (2017)
Theoretical Study on High Spectral Sensitivity Interferometer Based on Superluminal and Slow Light Technology
Cai Yuanxue, Ming Chengguo, and Zhang Yundong
We analyze the normal and anomalous dispersion characteristics of optical materials, and prove that a kind of interferometer based on dispersion characteristics of optical materials can realize the combination of superluminal light and slow light. We also theoretically analyze the spectral sensitivity of Mach-Zehnder (We analyze the normal and anomalous dispersion characteristics of optical materials, and prove that a kind of interferometer based on dispersion characteristics of optical materials can realize the combination of superluminal light and slow light. We also theoretically analyze the spectral sensitivity of Mach-Zehnder (M-Z) interferometer based on superluminal and slow light technology. Compared with the conventional M-Z interferometer which has the same structure with the above interferometer and the M-Z interferometer based on slow light technology, the spectral sensitivity of the M-Z interferometer based on superluminal and slow light technology increases sharply..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 93002 (2017)
Analysis of Methanol/Ethanol Diesel Identification and Content Determination Based on the Mid-Infrared Spectra
Ouyang Aiguo, Zhang Yu, Tang Tianyi, and Liu Yande
In order to realize the identification and content determination of methanol/ethanol diesel, the methanol diesel and ethanol diesel are prepared in the laboratory and divided into two groups by principal component analysis. Based on the mid-infrared spectra method, the preprocessing spectra are produced by smoothing, bIn order to realize the identification and content determination of methanol/ethanol diesel, the methanol diesel and ethanol diesel are prepared in the laboratory and divided into two groups by principal component analysis. Based on the mid-infrared spectra method, the preprocessing spectra are produced by smoothing, baseline correction, multiplicative scatter correction and normalization of the spectral data. The least squares support vector machine (LSSVM) prediction model is used to predict methanol/ethanol content, and the error rate is lower than 7.1%. The simulated results show that the correlation coefficient and the mean square error of the LSSVM prediction for methanol content of methanol diesel are 0.9791 and 1.7201; the correlation coefficient and root mean square error are 0.9802 and 2.9563 for ethanol content of ethanol diesel, respectively. The experimental results show that the proposed model is a promising choice to identification and content determination of methanol/ethanol diesel..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 93003 (2017)
Ultrafast Optics
Noise-Removing Technology of Frequency-Resolved Optical Gating Traces
Sun Shang′ao, Zhang Liuyang, Qu Yuqiu, Yang Ying, and Zhang Xin
Based on the analysis of noise sources in the practical frequency-resolved optical gating (FROG) traces, a reasonable program to remove noises is designed. The direct reconstruction and the reconstruction after noise removing are conducted for the FROG traces with the analogue noises, respectively. The root-mean-squareBased on the analysis of noise sources in the practical frequency-resolved optical gating (FROG) traces, a reasonable program to remove noises is designed. The direct reconstruction and the reconstruction after noise removing are conducted for the FROG traces with the analogue noises, respectively. The root-mean-square error of the latter is lower by one order of magnitude than that of the former, which confirms that this noise-removing program is effective. The FROG system is set up and the FROG trace of a practical pulse is obtained. By analyzing and comparing the results obtained from these two reconstruction ways, it is found that the reconstructed pulse obtained by the noise removing way is much closer to the real pulse, which verifies the necessity of noise removing..
Laser & Optoelectronics Progress
- Publication Date: Jan. 01, 1900
- Vol. 54, Issue 9, 93201 (2017)
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