高动态科学级CMOS相机设计与成像分析

摘要

In order to satisfy the demand of the imaging system under the global exposure mode of high dynamic range and high sensitivity, we designed a camera based on the CIS-2521 scientific CMOS image sensor, implementing the correlated quadruple sampling algorithm in the FPGA by analyzing the feature of CIS-2521's pixel readout structure and combining its built-in circuit of correlative double sample, and it denoises the vertical noise obviously.The imaging system has higher output dynamic range of the image data by designing a curve matching the double gain channels.The output image peak signal to noise ratio of the camera can reach 62.9 dB under the room temperature, and can reach 74.3 dB using the semiconductor refrigeration.The dynamic range of the camera can reach 78.2 dB according to EMVA1288 standard.The designed camera can realize the global exposed real time imaging output with high definition and high dynamic range for 2 560×2 160 and 16 bits images under 50 fps, and can satisfy the demand of the high frame frequency and high dynamic range under the low brightness.%为了满足高动态范围高灵敏度的全局曝光模式下成像系统的需求,基于CIS-2521科学级CMOS图像传感器设计了一个相机系统,通过分析CIS-2521芯片像素读出结构特点,通过芯片内部模拟相关双采样与FPGA片内数字域相关双采样完成相关四采样算法,列向噪声去除效果明显.通过设计曲线拟合双增益通道图像数据合成输出,保证了系统成像有较高输出动态范围.相机常温下输出图像峰值信噪比达62.9 dB,采用半导体制冷后输出图像峰值信噪比74.3 dB.根据EMVA1288标准实测相机动态范围达到78.2 dB,设计的相机系统实现了每秒50帧2 560×2 160像素,16 bit深度高清晰度高动态范围图像的实时全局曝光成像输出,能够满足低照度条件下的高帧频高动态范围成像的需求.