640×512帧转移EMCCD相机时序设计

640×512 Frame Transfer EMCCD Camera Timing Sequence Design

为了实现640×512分辨率的EMCCD(Electron-Multiplying CCD)在1×10^(-3)lx照度条件下25fps连续动态成像,设计了对应的相机。搭建了相机硬件平台,分析了EMCCD工作时序、AFE工作时序、BT.656编码和Camera Link编码时序。利用硬件描述语言在FPGA中产生了相应的驱动时序。实现了EMCCD曝光和读出控制,AFE相关双采样和光学暗电平钳位,模拟视频信号逐行变隔行和插值拉伸以及Camera Link协议的并串转换。通过实际测量和分析,相机在模拟夜天光1×10^(-3)lx照度,EMCCD增益1000倍,镜头焦距25 mm,F1.4的条件下,能同时输出模拟视频和数字视频,成像帧率25 fps,信噪比21.8 d B。

An EMCCD camera was introduced to realize 25 fps continuous dynamic imaging with 640×512 resolution under 1×10^(-3) lx illuminance.Through the construction of the camera hardware platform,as well as the analysis of the EMCCD working timing,AFE working timing,BT.656 encoding,and Camera Link encoding timing,the camera uses FPGA and HDL to generate the corresponding driver timing.This includes EMCCD exposure and readout,AFE-correlated double sampling and optical dark clamping,analog video progressive to interlacing and stretching,and Camera Link parallel to serial conversion.The camera operates under the following conditions:1×10^(-3) lx simulated night sky illuminance,1000×EMCCD gain,25 mm lens focus,and F1.4;the experimental results demonstrate the imaging frame rate of 25 fps and SNR of 21.8 dB.