The liquid crystal spatial light modulator （LC SLM） is very suitable for wavefront correction and optical testing and can produce a wavefront with large phase change and high accuracy. The LC SLM is composed of thou...The liquid crystal spatial light modulator （LC SLM） is very suitable for wavefront correction and optical testing and can produce a wavefront with large phase change and high accuracy. The LC SLM is composed of thousands of pixels and the pixel size and shape have effects on the diffractive characteristics of the LC SLM. This paper investigates the pixel effect on the phase of the wavefront with the scalar diffractive theory. The results show that the maximum optical path difference modulation is 41μm to produce the paraboloid wavefront with the peak to valley accuracy better than λ/10. Effects of the mismatch between the pixel and the period, and black matrix on the diffraction efficiency of the LC SLM are also analysed with the Fresnel phase lens model. The ability of the LC SLM is discussed for optical testing and wavefront correction based on the calculated results. It shows that the LC SLM can be used as a wavefront corrector and a compensator.展开更多
Single pixel imaging is a novel imaging technique,and it becomes a focus of research in recent years due to its advantages such as high lateral resolution and high robustness to noise.Imaging speed is one of the criti...Single pixel imaging is a novel imaging technique,and it becomes a focus of research in recent years due to its advantages such as high lateral resolution and high robustness to noise.Imaging speed is one of the critical shortcomings,which limits the further development and applications of this technique.In this paper,we focus on the issues of imaging efficiency of a single pixel imaging system.We propose semi-continuous wavelet transform(SCWT)protocol and introduce the protocol into the single pixel imaging system.The proposed protocol is something between continuous wavelet transform and discrete wavelet transform,which allows the usage of those smooth(usually non-orthogonal,and they have advantages in representing smooth signals compressively,which can improve the imaging speed of single pixel imaging)wavelets and with limited numbers of measurements.The proposed imaging scheme is studied,and verified by simulations and experiments.Furthermore,a comparison between our proposed scheme and existing imaging schemes are given.According to the results,the proposed SCWT scheme is proved to be effective in reconstructing a image compressively.展开更多
电子轰击有源像素传感器(electron bombarded active pixel sensor,EBAPS)是一种新型的真空-固体混合型微光夜视器件,而调制传递函数(modulation transfer function,MTF)作为EBAPS的性能参数之一,能够反映成像系统对不同频率成分的传递...电子轰击有源像素传感器(electron bombarded active pixel sensor,EBAPS)是一种新型的真空-固体混合型微光夜视器件,而调制传递函数(modulation transfer function,MTF)作为EBAPS的性能参数之一,能够反映成像系统对不同频率成分的传递能力,但目前国内缺少相应的测试手段。因此,为了表征并评价EBAPS的成像质量,基于像增强器狭缝法测试MTF的原理,设计并搭建了一套EBAPS的MTF测试系统。通过驱动EBAPS器件,利用USB接口将采集到的数据传输至上位机进行图像分析,对狭缝图像进行处理获得线扩散函数(line spread function,LSF),经离散傅里叶变换后得到相应的调制传递函数曲线。在狭缝靶标处照度为2×10^(-2) lx时,一定范围内随着电压升高,EBAPS的MTF先升高后降低,且在外加-1 000 V时取得最大值。在光成像模式下,微调狭缝与传感器成像面的相对位置,连续5次测试得到几个重要频率点的MTF值的标准差均低于0.01,稳定性较好。展开更多
Background HEPS-BPIX is a prototype of photon counting pixel detector developed for the High Energy Photon Source.It consists of 16 silicon pixel modules which should be tested individually to ensure the function and ...Background HEPS-BPIX is a prototype of photon counting pixel detector developed for the High Energy Photon Source.It consists of 16 silicon pixel modules which should be tested individually to ensure the function and performance.Purpose Due to various factors such as the non-uniformity of the processes and voltage drop,the response of each pixel in the silicon pixel module is not identical completely.The response difference of pixels can be minimized by the threshold calibration.This system is developed for the quality test and calibration of the silicon pixel modules.Methods The system consists of a mother board,a control board and a data acquisition(DAQ)system.The mother board provides necessary resources including power supplies and the fanout of calibration signals.Besides,it can be used to test the connectivity by monitoring the power states.The control board reads data out and provides the clock,trigger and configuration data for the silicon pixel module.The DAQ system sends the control commands and receives the readout data through an Ethernet link.Results Compared with the previous readout system,this designed system has a lower noise level and better scanning curves making the calibration more accurate.And it has been successfully applied to the comparison experiments of the through silicon via and wire-bonding silicon pixel modules.Conclusion The results show that this test system can be used to the quality test and calibration of the silicon pixel modules.In addition,the system can be adapted to the measurement of different pixel array detector modules.展开更多
基金Project supported by the National Natural Science Foundation of China （Nos 60578035, 50473040） and the Science Foundation of Jilin Province （Nos 20050520, 20050321-2）.
文摘The liquid crystal spatial light modulator （LC SLM） is very suitable for wavefront correction and optical testing and can produce a wavefront with large phase change and high accuracy. The LC SLM is composed of thousands of pixels and the pixel size and shape have effects on the diffractive characteristics of the LC SLM. This paper investigates the pixel effect on the phase of the wavefront with the scalar diffractive theory. The results show that the maximum optical path difference modulation is 41μm to produce the paraboloid wavefront with the peak to valley accuracy better than λ/10. Effects of the mismatch between the pixel and the period, and black matrix on the diffraction efficiency of the LC SLM are also analysed with the Fresnel phase lens model. The ability of the LC SLM is discussed for optical testing and wavefront correction based on the calculated results. It shows that the LC SLM can be used as a wavefront corrector and a compensator.
基金the Natural Science Foundation of Jilin Province,China(Grand No.YDZJ202101ZYTS030)。
文摘Single pixel imaging is a novel imaging technique,and it becomes a focus of research in recent years due to its advantages such as high lateral resolution and high robustness to noise.Imaging speed is one of the critical shortcomings,which limits the further development and applications of this technique.In this paper,we focus on the issues of imaging efficiency of a single pixel imaging system.We propose semi-continuous wavelet transform(SCWT)protocol and introduce the protocol into the single pixel imaging system.The proposed protocol is something between continuous wavelet transform and discrete wavelet transform,which allows the usage of those smooth(usually non-orthogonal,and they have advantages in representing smooth signals compressively,which can improve the imaging speed of single pixel imaging)wavelets and with limited numbers of measurements.The proposed imaging scheme is studied,and verified by simulations and experiments.Furthermore,a comparison between our proposed scheme and existing imaging schemes are given.According to the results,the proposed SCWT scheme is proved to be effective in reconstructing a image compressively.
基金the State Key Laboratoryof Particle Detection and Electronics, SKLPDE-ZZ-202002.
文摘Background HEPS-BPIX is a prototype of photon counting pixel detector developed for the High Energy Photon Source.It consists of 16 silicon pixel modules which should be tested individually to ensure the function and performance.Purpose Due to various factors such as the non-uniformity of the processes and voltage drop,the response of each pixel in the silicon pixel module is not identical completely.The response difference of pixels can be minimized by the threshold calibration.This system is developed for the quality test and calibration of the silicon pixel modules.Methods The system consists of a mother board,a control board and a data acquisition(DAQ)system.The mother board provides necessary resources including power supplies and the fanout of calibration signals.Besides,it can be used to test the connectivity by monitoring the power states.The control board reads data out and provides the clock,trigger and configuration data for the silicon pixel module.The DAQ system sends the control commands and receives the readout data through an Ethernet link.Results Compared with the previous readout system,this designed system has a lower noise level and better scanning curves making the calibration more accurate.And it has been successfully applied to the comparison experiments of the through silicon via and wire-bonding silicon pixel modules.Conclusion The results show that this test system can be used to the quality test and calibration of the silicon pixel modules.In addition,the system can be adapted to the measurement of different pixel array detector modules.
