光学学报, 2020, 40(6): 0628002, 网络出版: 2020-03-01

基于太阳漫反射板线阵CCD相对辐射定标方法研究

A Relative Radiometric Calibration Method Based on Solar Diffuser Research for a Linear Array CCD Detector
作者单位

1中国科学院安徽光学精密机械研究所通用光学与表征技术重点实验室, 安徽 合肥 230031

2中国科学技术大学, 安徽 合肥 230026

3中国资源卫星应用中心, 北京 100094

4北京空间机电研究所, 北京 100094

摘要
针对推扫型光学遥感器成像光学系统中线阵CCD探测器各像元响应不一致的现象,提出一种基于太阳漫反射板星上相对辐射定标方法。该方法以实验室积分球定标数据作为参考标准,对星上太阳漫反射板定标数据进行平场校正,消除了相机视场内杂散光及双向反射分布函数(BRDF)分布对相对定标结果带来的影响;进而得到各像元的相对定标系数,最后将相对定标系数应用于海洋、戈壁滩、云层三种不同地物目标场景。结果表明:三种地物场景的原始影像中存在的各种垂直条纹噪声可以得到有效消除;相对定标后各场景影像条纹系数均优于0.0045;基于太阳漫反射板相对定标方法可对线阵CCD探测器进行大动态范围内相对辐射校正,具有较高的时效性和定标精度,以满足星上相对辐射定标需求。
Abstract
In this study, we propose an on-board relative radiometric method based on a solar diffuser to correct the non-uniformity of the pixel response of the linear array CCD detector based on the imaging optical system of the push-room optical remote sensor. The proposed method uses laboratory integrating sphere calibration data as a reference standard to perform flat-field correction on the onboard calibration data, and the influences of the stray light in the field of view of the camera and the distribution of the bidirectional reflectance distribution function (BRDF) on the relative calibration results are eliminated; further, we obtain the relative calibration coefficients of each pixel, which can be applied to three different objects, i.e., the ocean, the Gobi desert, and the cloud. The results prove that the various vertical striping noises in the raw image can be effectively eliminated and that the image streaking metrics with respect to each scene is better than 0.0045 after relative calibration. Based on the solar diffuser, relative radiometric calibration for the linear array CCD detector in the large dynamic range can be realized, exhibiting considerable timeliness and calibration accuracy.
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