空间CCD相机辐射校正算法分析

Analysis of Relative Radiometric Calibration Algorithm of Space CCD Camera

空间CCD相机对均匀景物响应的不一致在图像中表现为条带现象,相对辐射校正可以减弱或消除条带效应。相对辐射校正可以使用不同的算法,但效果不同。文章选取了某空间CCD相机的实验室辐射定标数据,采用基准的归一化系数法和最小二乘法,分别计算该相机的3组相对辐射校正系数,并对实验室原始辐射定标数据进行相对辐射校正,验证3种算法的校正效果。通过相对辐射校正后的图像和3种算法的辐射校正残余误差分析,认为以所有辐亮度DN(digital number)均值为基准的归一化系数法的校正效果在多数辐亮度级下好于最小二乘法。最后分析了相机像元响应线性度和算法辐射校正残余误差的关系。

Striping and banding in the image caused by the non-uniformity response of space charge-coupled device（CCD） camera can be corrected by relative radiometric calibration. There are different rela-tive radiometric calibration methods which have different effects. In this paper, three groups of relative calibration coefficient are obtained through the methods of least-square and two kinds of normalized coefficient procedure. The original images are corrected by using the coefficients to validate its calibration effect. The result of normal-ized coefficient method based on the mean DN of all radiance levels is better than that of least-square method at most of the radiance levels. The relationship between linearity and calibration error is analyzed at last.