TDI-CMOS图像传感器像移降质模型研究

Research of Image Motion Degradation Model for TDI-CMOS Image Sensor

根据TDI-CMOS图像传感器的工作原理和曝光时序,建立了像移作用下传感器的降质模型,并在此基础上,推导了传感器沿轨和跨轨方向线性非正常像移的MTF模型,着重分析了累加级数、行选时间、像素曝光时间和速度同步误差对线性非正常像移MTF的影响.为更好地分析不同像移形式对成像质量的影响,建立了TDI-CMOS图像传感器动态链路仿真模型,对传感器沿轨和跨轨方向存在线性非正常像移情况进行了仿真,并利用刃边法计算降质图像的MTF值.仿真结果表明,沿轨和跨轨方向线性非正常像移MTF不仅与速度同步误差有关系,还与累加级数、行选时间和像素曝光时间有关系.提出的传感器动态链路仿真模型能够用于仿真不同形式的像移对成像质量的影响.

According to the operation principle and exposure schedule of time delay integration CMOS image sensor (TDI-CIS), a degradation model under the influence of image motion was established. Based on this model, the corresponding modulation transfer function (MTF) model was derived when the linear abnormal image motion appears along the track or cross the track direction. Impacts of TDI stage, readout time, pixel integration time and speed synchronization error on the corresponding MTF were studied. In order to analyze the influence of different kinds of image motion on the image quality, a dynamic imaging simulation model of TDI-CIS was established. Simulations of TDI-CIS imaging process under different circumstances were carried out. Then knife-edge method was used to calculate the value of MTF. The simulation results show that MTF of the linear abnormal image motion is influenced by TDI stage, readout time, pixel integration time and speed synchronization error. The dynamic imaging simulation model proposed can be used to simulate the influence of different kinds of image motion on image quality.