Infrared nonuniformity correction and radiometric calibration technology using U-shaped blackbody

摘要

A nonuniformity correction and radiometric calibration algorithm for infrared focal plane array is presented, combined with two-point correction along the U-shaped blackbody rim. The format of Infrared Focal-Plane Array (IRFPA) is larger and larger now; however, due to technical limitations and material defects in production, the drift of the IRFPA response during their working is unavailable. It will leads to non-uniformity of the thermal imaging systems which has become an important affect element of the efficiency for the practical use of the thermal imaging equipments. Point to the problems of traditional radiation calibration and correction methods, we proposed a dynamic infrared calibration and correction technology using U-shaped blackbody. With the help of blackbody in low and high temperature, two-point correction is executed initially to perimeter detectors. Then based on the scene information and shift between adjacent frames, a special algebraic algorithm is proposed to transport correction parameters from perimeter detectors to those interior un-corrected ones. In this way, the correction parameters of the whole field of view (FOV) are calculated. The temperature of the U-shaped blackbody is controllable, so dynamic infrared calibration can be done after nonuniformity correction to modification the drift of the original calibration table. A U-shaped blackbody is designed and an experimental platform is built to evaluate the algorithm. The U-shaped perimeter blackbody is designed to be able to scale out periodically so as to continuously update the correction parameters. It proves to be able to achieve two-point correction for accuracy, without covering the central FOV.