天问一号高分辨率相机成像参数设置及定标测试  

Imaging parameter setting and calibration test of Tianwen-1 high-resolution camera

作　　者：刘文光[1] 王晓东[1] 董吉洪[1] 张帆[1] LIU Wenguang;WANG Xiaodong;DONG Jihong;ZHANG Fan(Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,China)

机构地区：[1]中国科学院长春光学精密机械与物理研究所,吉林长春130033

出　　处：《光学精密工程》2022年第2期178-184,共7页Optics and Precision Engineering

基　　金：国家自然科学基金项目(No.62005266)。

摘　　要：为了使天问一号有效载荷高分辨率相机在轨工作期间获取到高质量图像,对高分辨率相机成像参数的设置进行说明。结合实验室定标测试结果,给出了相机在轨工作默认参数以及不同地面反射率和不同太阳高度角下的成像参数。首先,根据大气辐射传输模型计算出各谱段在相机入瞳处的辐亮度。接着,利用光电转换模型计算出CCD探测器信号输出电荷值。然后,在满足图像信噪比大于100的系统要求下,计算出相机成像参数。最后,在实验室条件下进行相机光谱定标和辐射定标测试及定标误差分析。实验结果表明:高分辨率相机的视频响应曲线呈线性关系,图像灰度值和成像参数呈线性关系,线性拟合相关系数均在0.999以上,线阵CCD各谱段响应非均匀性均不超过1%,典型照明条件下信噪比不低于100倍,相对辐射定标不确定度优于3%,绝对辐射定标不确定度优于7%。理论计算与实验室定标测试结果基本符合,成像参数设计合理,定标测试结果满足系统要求。To obtain high-quality images during the operation of the Tianwen-1 payload high-resolution camera,the imaging parameter settings were investigated. Combined with the results of laboratory calibration experiments,the default parameters of the camera in orbit and the imaging parameters under different ground reflectivities and sun altitudes were determined. First,the radiance of each spectral segment at the entrance pupil of the camera was calculated based on the atmospheric radiation transfer model. Then,the output charge value of the CCD detector was obtained by applying the photoelectric conversion model. Furthermore,the imaging parameters of the camera were obtained,and were found to meet the requirement of SNR > 100. Finally,spectral calibration and radiometric calibration were conducted under laboratory conditions,and the calibration error was analyzed. The experimental results indicate that the video response of the high-resolution camera is linear,relationship between the gray value and imaging parameter is linear,correlation coefficients of linear fitting are all above 0. 999,non-uniformity of each spectral segment is less than 1%,and SNR is no less than 100 under typical lighting conditions. The relative radiometric calibration uncertainty is better than 3%,and the absolute radiometric calibration uncertainty is better than 7%.The results of the theoretical calculation and calibration are found to be basically consistent. Thus,the imaging parameters are designed reasonably,and the calibration results meet the system requirements.

关 键 词：天问一号 高分辨率相机 成像参数 定标测试 

分 类 号：V19[航空宇航科学与技术—人机与环境工程] V447.1