空间CCD相机高精度在轨调制传递函数估算  

High-Precision On-Orbit Assessment of MTF for Space CCD Camera

作　　者：李进[1,2] 邢飞[1,2] 王翀[1,2] 

机构地区：[1]清华大学精密仪器系,北京100084 [2]清华大学精密测试与仪器国家重点实验室,北京100084

出　　处：《光学学报》2015年第2期134-143,共10页Acta Optica Sinica

基　　金：国家863计划(2012AA121503;2012AA121603);国家自然科学基(61377012;60807004);中国博士后科学基金(2014M550720)

摘　　要：空间电荷耦合器件(CCD)相机在轨调制传递函数(MTF)估算由于噪声影响、边缘方向不够准确以及边缘扩展函数(ESF)构建精度低,而最终导致MTF估算精度低,针对此问题提出了一种适于空间CCD相机的高精度在轨调制传递函数估算方法。先根据CCD动态成像特点建立像移速度模型,求出精确的刃边方向,然后提取出满足要求的刃边图像。在考虑噪声情况下修正调制传递函数理论模型,并提出基于CCD相机传递函数参数模型的线扩展函数构建方法,对构建的线扩展函数进行求导和傅里叶变换得到估算的MTF。实验结果表明,此方法可以高效地在轨估算MTF,与传统方法相比,MTF估算的值提高了28.71%,有效性地提升了在轨MTF估算精度。Given that on-orbit modulation transfer function （MTF） for space charge coupled device （CCD） camera has the disadvantage of low assessing precision caused by noise in the process of image acquisition, a new high-precision assessment approach of MTF for space CCD camera is proposed. The accurate knife-edge direction is extracted according to the image motion velocity model which is built based on the characteristics of CCD dynamic imaging. The theory model of MTF is corrected when noise is considered. And the line spread function （LSF） is computed based on the parameter transfer function model of CCD camera. The LSF performs the derivative operation and Fourier transform to obtain the MTF. Experimental analysis denotes that the proposed method can efficiently estimate on-orbit MTF. Compared with the traditional knife-edge method, the assessment value of MTF has improvement of 28.71%. The proposed approach can effectively solve the problem of lower precision on-orbit assessment of MTF.

关 键 词：遥感 空间CCD相机 调制传递函数 在轨估算 

分 类 号：O436[机械工程—光学工程]