基于U形边框黑体光阑的红外成像动态辐射定标与校正技术

Dynamic infrared nonuniformity correction and radiometric calibration technology using U-shaped blackbody

针对传统的辐射定标与校正方法存在的问题,研究提出了一种基于U形边框黑体视场光阑的红外成像辐射定标与校正技术。该技术可在不遮挡中心视场的情况下完成动态非均匀校正,因为边框黑体的温度是可控的,所以在非均匀校正的基础上可以进行红外成像系统的动态辐射定标,以修正热成像系统出厂辐射定标的漂移。算法执行时,将边框黑体视场光阑分别在高、低温下伸入视场,与原始辐射定标数据进行对比,计算出辐射定标的修正参数,修正补偿原始辐射定标查找表,减小动态辐射定标器的体积和质量,并避免辐射标定时对成像视场的遮挡。设计并搭建了基于U形边框黑体光阑的实验平台,该平台上的成像实验表明:校正效果明显,辐射定标修正后的测温误差小于0.5 K。

A dynamic nonuniformity correction and radiometric calibration algorithm for infrared focal plane array was presented.Point to the problems of traditional radiation calibration and correction methods,a dynamic infrared calibration and correction technology using U-shaped blackbody was proposed which was a new conception.The temperature of the U-shaped blackbody was controllable,so dynamic infrared calibration could be done after nonuniformity correction so as to modify the drift of the original calibration table.The U-shaped blackbody diaphragm stretched out in high and low temperature respectively.After comparing that with the initial calibration data,the desired amended parameters were calculated to update the whole initial lookup table for radiometric correction.This algorithm could amend the drifts from initial radiometric calibration data,reduce the volume and weight of dynamic radiometric calibrator,and totally avoid the blocking of the FOV in traditional radiometric calibration.An U-shaped blackbody was designed and an experimental platform was built to evaluate the algorithm.It proves to get a satisfying correction effect after being tested by using real infrared images,and the error is less to 0.5 K after radiometric calibration modification.