Journals >Opto-Electronic Engineering
Contents
2021
Volume: 48 Issue 10
8 Article(s)
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Research Articles
High dimensional stability polyimide membrane material for space optical imaging system
Yin Jiajia, Mao Danbo, Fan Bin, Bian Jiang, and Du Junfeng
Polymer membranes are attractive mirror candidate for the space large aperture lightweight optical imaging system. But there are strict requirements for mirror material because of the harsh space application environment and the high optical imaging quality requirement. The dimensional stability is one of the most imporPolymer membranes are attractive mirror candidate for the space large aperture lightweight optical imaging system. But there are strict requirements for mirror material because of the harsh space application environment and the high optical imaging quality requirement. The dimensional stability is one of the most important properties for optical mirror material. In this research, based on the molecular structure design, rigid molecular chain and hydrogen chain have been introduced to polyimide to improve the thermal dimensional stability. At the same time, the excellent mechanical, optical and thermal properties of the polyimide membrane have been guaranteed. The obtained optical grade polyimide has high dimensional stability, and the optical stability of the space environment and the excellent comprehensive properties are good candidates for the lightweight optical application..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 10, 210150 (2021)
Research on dispersion compensation technology for SD-OCT system
Jiang Panqiu, and Wang Pinghe
Dispersion compensation for the data processing of the spectral domain optical coherence tomography (SD-OCT) system is an important way to improve the imaging quality of the system. A dispersion compensation method for spectral domain optical coherence tomography based on numerical polynomial fitting analysis is proposDispersion compensation for the data processing of the spectral domain optical coherence tomography (SD-OCT) system is an important way to improve the imaging quality of the system. A dispersion compensation method for spectral domain optical coherence tomography based on numerical polynomial fitting analysis is proposed in this paper. This method obtains the dispersion factor by fitting the phase of the interference signal and removes the dispersion mismatch terms, which can significantly improve the system axial resolution compared with non-dispersion compensation. The SD-OCT system is used to measure the axial resolution and signal-to-noise ratio (SNR) at different positions of the optical path difference, and the effectiveness and reliability of the method are verified by analyzing the axial resolution and the SNR of the system before and after the dispersion compensation technology. Finally, we found that the third-order dispersion compensation has a visible optimization effect within the imaging depth of ~1.5 mm..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 10, 210184 (2021)
Video object segmentation algorithm based on adaptive template updating and multi-feature fusion
Wang Shuiyuan, Hou Zhiqiang, Wang Nan, Li Fucheng, Pu Lei, and Ma Sugang
In order to solve the problem that SiamMask cannot adapt to the change of target appearance and the lack of use of feature information leads to rough mask generation, this paper proposes a video object segmentation algorithm based on the adaptive template update and the multi-feature fusion. First of all, the algorithmIn order to solve the problem that SiamMask cannot adapt to the change of target appearance and the lack of use of feature information leads to rough mask generation, this paper proposes a video object segmentation algorithm based on the adaptive template update and the multi-feature fusion. First of all, the algorithm adaptively updates the template using the segmentation results of each frame; secondly, the hybrid pooling module is used to enhance the features extracted in the fourth stage of the backbone network, and the enhanced features are fused with the rough mask; finally, the feature fusion module is used to refine the rough mask stage by stage, which can effectively combine the spliced features. Experimental results show that, compared with SiamMask, the performance of the proposed algorithm is significantly improved. On the DAVIS2016 data-set, the region similarity and contour similarity of this algorithm are 0.727 and 0.696, respectively, which is 1.0% and 1.8% higher than that of the benchmark algorithm, and the speed reaches 40.2 f/s. On the DAVIS2017 data-set, the region similarity and contour similarity of this algorithm are 0.567 and 0.615, respectively, which is 2.4% and 3.0% higher than that of the benchmark algorithm, and the speed reaches 42.6 f/s..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 10, 210193 (2021)
Analysis of detection probability performance of SiPM LiDAR under sunlight
Chen Jianguang, Ni Xuxiang, Yuan Bo, and Yan Huimin
Silicon photomultiplier (SiPM) is an array composed of hundreds or even thousands of single photon avalanche diode (SPAD). It has the advantages of high gain, easy integration into the array and anti-interference, and has a wide range of application prospects in LiDAR ranging. We analyzed the laser radar ranging signalSilicon photomultiplier (SiPM) is an array composed of hundreds or even thousands of single photon avalanche diode (SPAD). It has the advantages of high gain, easy integration into the array and anti-interference, and has a wide range of application prospects in LiDAR ranging. We analyzed the laser radar ranging signal and noise model, simulated the output of SiPM under sunlight, and obtained the corresponding mean value through Gaussian fitting. On the basis that the probability of being excited after SPAD received photons obeys the Poisson distribution, the calculation formula of SiPM analog output affected by background light when the background photoelectron is 0.001 /ns~0.01 /ns and the detector dead time is 5 ns~50 ns was given. Finally, we derived the expression of target detection probability. The experimental results of laser ranging detection probability under outdoor ambient light are consistent with theoretical calculations..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 10, 210196 (2021)
Wavefront distortion prediction method based on motion estimation
Zhou Xin, and Li Xinyang
In the actual adaptive optics control system, the time delay causes the mismatch between the correction profile generated by the corrector and the actual wavefront distortion, which leads to correction lag error. Under the atmospheric frozen flow turbulence assumption, a wavefront distortion prediction method based on In the actual adaptive optics control system, the time delay causes the mismatch between the correction profile generated by the corrector and the actual wavefront distortion, which leads to correction lag error. Under the atmospheric frozen flow turbulence assumption, a wavefront distortion prediction method based on motion estimation is proposed to compensate for the time delay. The template matching algorithm is used to estimate the atmospheric turbulence motion direction, according to the wavefront restored images of the reference frame and the current frame, and then the current frame is moved to predict the next frame. The prediction method applicability is evaluated, and the influence of backtracking frames on the prediction effect is discussed by comparing the simulation data of different sampling frequencies and different transverse wind speeds. The residual error is calculated with the template matching algorithm and the least recursive squares (RLS) algorithm. The simulation results show that the method performs better when the variation tendency of wavefront restored images is obvious. Therefore, the prediction effect can be maintained better in severe conditions. Finally, the prediction method is verified by using the actual observation data of Sirius, and the algorithm still keeps the prediction effect..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 10, 210288 (2021)
Ghost convolution adaptive retinal vessel segmentation algorithm
Liang Liming, Zhou Longsong, Chen Xin, Yu Jie, and Feng Xingang
In order to solve the problems in retinal vessel segmentation, such as blurred main vessel profile, broken micro-vessels, and missegmented optic disc boundary, a ghost convolution adaptive retinal vessel segmentation algorithm is proposed. The first algorithm uses ghost convolution to replace the common convolution in In order to solve the problems in retinal vessel segmentation, such as blurred main vessel profile, broken micro-vessels, and missegmented optic disc boundary, a ghost convolution adaptive retinal vessel segmentation algorithm is proposed. The first algorithm uses ghost convolution to replace the common convolution in neural network, and the ghost convolution generates rich vascular feature maps to make the target feature extraction fully carried out. Secondly, the generated feature images are adaptive fusion and input to the decoding layer for classification. Adaptive fusion can capture image information at multiple scales and save details with high quality. Thirdly, in the process of accurately locating vascular pixels and solving image texture loss, a dual-pathway attention guiding structure is constructed to effectively combine the feature map at the bottom and the feature map at the top of the network to improve the accuracy of vascular segmentation. At the same time, Cross-Dice Loss function was introduced to suppress the problem of uneven positive and negative samples and reduce the segmentation error caused by the small proportion of vascular pixels. Experiments were conducted on DRIVE and STARE datasets. The accuracy was 96.56% and 97.32%, the sensitivity was 84.52% and 83.12%, and the specificity was 98.25% and 98.96%, respectively, which proves the good segmentation effect..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 10, 210291 (2021)
Experimental research on laser parallel processing of two-dimensional codes
Zhai Zhongsheng, Liu Chunli, Li Mengyu, Chen Bo, and Liu Dun
Aiming at the problem that most of the output energy of laser single-beam processing of two-dimensional codes is wasted and the processing efficiency is low, this paper adopts a multi-beam parallel processing method to improve the processing efficiency. The simulation studies the effect of the QR code processing fillinAiming at the problem that most of the output energy of laser single-beam processing of two-dimensional codes is wasted and the processing efficiency is low, this paper adopts a multi-beam parallel processing method to improve the processing efficiency. The simulation studies the effect of the QR code processing filling rate, and contrast on recognition rate, and recognition time, and obtains a QR code recognizable range. Then use the femtosecond laser based on the parallel processing technology of the spatial light modulator to conduct experiments, and analyze the contrast and processing fill rate of the experimental results. The analysis results show that within the range of the QR code reading evaluation standard, the greater the processing filling rate is, the lower the recognition rate and the longer the recognition time are; similarly, the lower the contrast is, the lower the recognition rate and the longer the recognition time are. At the same time, experiments were performed on the single-beam laser processing of two-dimensional codes. The comparison of processing time and other parameters of the parallel processing and single-beam processing was analyzed, and the efficiency of the parallel processing was about 10 times higher than that of the single-beam processing..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 48, Issue 10, 210293 (2021)
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