帘幕式CMOS全局曝光成像技术（英文）

Design on Global Imaging Mode Based on Electronic Rolling Shutter CMOS

为了消除面阵CMOS航空相机高速成像时帘幕快门效应对成像质量的影响,分析了CMOS成像原理,开展了基于高速中心式机械快门与面阵CMOS图像传感器协同工作的全局曝光成像模式研究.建立了该成像模式下的航空高分辨率成像系统的信噪比模型与前向像移模型,并基于信噪比模型与前向像移模型论证存在合理的曝光时间参数.设计了体积小、质量轻、电驱动、曝光时间可准确控制的高速中心式机械快门,最短曝光时间可达1/2000s,快门效率最高达80%.对采用自主研发的国产CMOS图像传感器的航空摄影相机参数进行验证计算,并进行直升机载人带飞拍摄实验.影像结果表明:该成像模式曝光时间参数论证正确,影像无拉伸、扭曲及拖尾现象,相机动态传递函数为0.21(奈奎斯特截止频率处),能够满足实际应用需求.

In order to eliminate the influence of rolling shutter on image quality in higher speed mapping by a CMOS airborne digital camera,the combination imaging mode of matrix array CMOS and high speed central mechanical shutter is emphatically studied based on CMOS imaging principle.The forward motion model and Signal-to-Noise Ratio(SNR)model of matrix array CMOS resolution imaging system based on the combination imaging mode are proposed and the existence of the corresponding range of exposure is proved under the condition of suitable forward motion and SNR of the airborne digital camera.A small-sized electric and exposure controlled accurately high speed central mechanical shutter is designed with the shortest exposure(1/2 000 s)and the highest efficiency(80%).Finally,the correctness of the right range of exposure is verified by the experimental results of the radiation calibration of an airborne digital camera based on a domestic CMOS image sensor.The experimental data indicates that the parameter proven of combination imaging mode is right and the camera's dynamic MTF at Nyquist frequency(91 lp/mm)is 0.21 which meets the practical application requirement.