Influence of image motion on TDI imaging camera by distortion effect

With the Time Delayed and Integration (TDI) technology continues to evolve, Charge Coupled Devices (CCD) with TDI feature has been widely applied to high-resolution earth imaging system. However, in the push-broom imaging process, imaging system using TDI technology would inevitably be affected by the image motion, finally leading to blur image. The reason of image motion caused by optical system distortion in the process of TDI imaging was analyzed, formula of the image motion value was derived, the influence of optical system distortion on Modulation Transfer Function was analyzed, and the relationship between image quality deterioration caused by image motion and distortion was studied. Degradation of National Imagery Interpretability Rating Scale (NIIRS) parameters 驻NIIRS caused by image motion that generated by distortion was calculated for the TDI imaging system of which focal length was 9 000 mm, integral stage was 96, grounding sample distance was 0.6 m, F/p was 1, SNR was 50:1. The results showed when the derivative value of distortion was 6.493, NIIRS would reach -0.162 4, and would affect the image interpretation requirements. Finally, for this space camera, the restriction value of D'() without affecting interpretation requirements was given. This research could provide a reference for optical TDI remote sensing system design.