基于幂加权最小二乘拟合的红外相机辐射定标方法  

Radiometric Calibration Method for Infrared Camera Based on Power-weighted Least Squares Fitting

作　　者：金占雷[1] 晋利兵 张九双 徐丽娜[1] 鲍云飞[1] 李岩[1] JIN Zhanlei;JIN Libing;ZHANG Jiushuang;XU Lina;BAO Yunfei;LI Yan(Beijing Institute of Space Mechanics and Mechanics,Beijing 100094,China)

机构地区：[1]北京空间机电研究所,北京100094

出　　处：《光子学报》2024年第4期171-186,共16页Acta Photonica Sinica

基　　金：军科委基金项目。

摘　　要：分析了现有线性度计算方法的不足,提出基于偏差/测量值的新线性度评价方式,通过该方式最小二乘拟合的低端温度偏差比高端大一个数量级,并采用加权拟合提高系统响应线性度。在分析不同光谱的温度和辐亮度拟合函数基础上,提出一种基于辐亮度倒数幂加权最小二乘线性拟合的地面和星上辐射定标方法,确认最佳权重幂次,建立了幂次n=1的加权最小二乘拟合外黑体线性定标方程、内黑体线性定标方程、内外黑体辐亮度转换模型。针对星上内黑体高精度两点定标建立了基于加权最小二乘拟合内外黑体辐亮度转换模型;针对星上黑体发射率退化提出了基于恒星定标的红外相机星上内黑体辐亮度定标修正方法,建立了外黑体辐亮度、内黑体辐亮度和恒星辐亮度转换模型。采用加权线性拟合后,积分时间10 ms的低温端外黑体反演偏差由1.63 K下降到0.52 K,内黑体偏差反演温度偏差由0.83 K下降到0.39 K,系统响应线性度明显提升。Radiometric calibration is an important step in the high-precision quantitative application of infrared remote sensing camera,and in order to obtain uniform images,infrared cameras need to perform relative radiometric calibration.To obtain the true radiation value of the target,it is necessary to carry out absolute radiometric calibration to establish the quantitative relationship between the radiance of the entrance pupil and the DN value of the detector output,and then invert the true radiance value of the detection signal.In recent years,the requirements for radiometric calibration are getting higher and higher,so it is very necessary to deeply analyze and suppress the main influencing factors of infrared camera radiometric calibration accuracy to improve the radiometric calibration accuracy.There are many factors affecting the calibration accuracy of infrared system,and it can be seen from the analysis of the radiometric calibration accuracy of infrared camera that in addition to the non-uniformity of blackbody temperature,the nonlinearity of system response is an important source of radiometric calibration error,and improving the response linearity is an important means to improve the radiometric calibration accuracy of infrared camera.Least squares is the most commonly used method of data fitting and considers that all data are equally weighted to find the best matching function by minimizing the sum of squares of the error.The weighted least squares used by the Changchun optical machine of the Chinese Academy of Sciences reduces the linearity deviation caused by the temperature fluctuation of the calibration blackbody.For systematic errors such as the nonlinearity of the low-end response of the detector,how to use a better fitting algorithm to compromise has not been publicly studied.The nonlinearity of response is an important source of radiometric calibration error of infrared camera,and a terrestrial and on-orbit radiometric calibration method based on weighted least squares fitting is proposed to impro

关 键 词：红外遥感 辐射定标 线性度 幂加权 最小二乘拟合 

分 类 号：V447.1[航空宇航科学与技术—飞行器设计]