嫦娥一号卫星CCD立体相机焦平面设计与辐射定标

Focal Plane Design of Chang′e-1 Satellite CCD Stereo-Camera and Laboratory Radiation Calibration

讨论了嫦娥一号卫星CCD立体相机的特殊焦平面设计与实验室辐射定标。嫦娥一号卫星CCD立体相机采用一个广角、远心和消畸变的光学透镜配以面阵CCD作为接受器,完成三线阵自推扫成像。由于快门污染的存在,造成前视、正视与后视间的曝光时间存在较大的差异,这给辐射定标带来困难。本文提出了在面阵CCD焦平面前方设置一个三狭缝面罩的方案,从而使三行CCD的曝光时间基本相同,其残差在实验室辐射定标中作进一步修正,取得了较好的效果。本文还介绍了辐射定标中的其他重要性能指标,包括最短曝光时间的预估、饱和辐亮度的配准、暗电流检测、输出对输入的线性度以及相对定标、绝对定标的不确定度。

The special focal plane design and radiation calibration of Chang′e-1 satellite CCD stereo-camera are discussed.A wide-angle,telecentric and orthoscopic optical lens coupled with an area array CCD is used as a sensor in Chang′e-1 satellite CCD stereo camera to complete the three-line array self-propelling-sweeping imaging.But with the existence of shutter smear,the exposure time has some great differences between the foresight,vertical sight and back sight.It brings difficulties to the radiometric calibration.This paper presents a solution of setting up a three-slit mask in front of the CCD focal plane,which makes the three line exposure time almost the same and after the residuals in the laboratory calibration are further adjusted,good result is obtained.This paper also introduces other performances in the radiation calibration including the estimation of the shortest exposure time,the registration of the saturation radiance,the dark current noise test,the linearity of CCD pixel response and the uncertainties of relative calibration and absolute calibration.