TDI CCD相机大姿态角推扫成像行频精确匹配

Exact matching for row frequency of TDICCD camera under the big attitude angle scanning imaging

针对大视场TDI CCD相机大姿态角推扫成像过程中像面上像点像速差异较大,行频匹配精度不高引起的相机传函下降等问题,提出一种可支持粗调和精调的高精度行频匹配方法。首先,阐述了大视场遥感相机像速场的主要特点及像速匹配的关键问题;其次,深入分析了大视场TDI CCD相机大角度侧摆和前后摆推扫成像的像速场特性;然后,根据像速场特性制定同速匹配模式和异速匹配模式,分析传函特性,确定各自模式的使用条件;最后,提出了一种可支持粗调和精调的高精度行频匹配方法,并分析已实现行频匹配方法的精度,最终满足给定行频匹配精度要求。实验结果表明:在积分级数为96级,粗调方法使行频精度达到0.999 425,精调方法使行频精度达到0.999 928,2种方法均能使相机传函MTF优于0.998,从而实现大视场TDI CCD相机在各种大姿态角推扫成像条件下高质量成像。

With wide field of TDI CCD camera at the push of the attitude Angle of image point in the process of scanning imaging like speed difference is bigger ,the row frequency matching precision is not caused by higher camera function to drop ,a kind of coarse and fine adjustment precision horizontal frequency matching method was put forward . First of all ,the large field of TDI CCD camera as the main characteristic of the velocity field and as the key problems of speed matching was expounded ;Secondly ,in the big field of TDI CCD camera Angle side swing and swing pushed sweeping imaging before and after in-depth analysis of the characteristics as velocity field ;Then ,according to the characteristics of the velocity field choose image speed matching mode of the same speed and the different speed , analysis the functional features ,the using condition of each mode ;Finally ,this paper proposes a support of coarse and fine adjustment precision horizontal frequency matching method ,and analysis of the accuracy of the implemented row frequency matching method , ultimately meet the requirements of a given row frequency matching accuracy . The experimental results show that the integral series for level 96 ,coarse adjustment method can make the precision of the row frequency 0 .999 425 ,fine adjustment method can make the precision of the row frequency 0 .999 928 ,two methods can make the camera pass letter MTF is better than 0 .998 ,thus realize the wide field of TDICCD camera under the condition of all kinds of big push attitude Angle scanning imaging with high quality imaging .