Radiometric calibration algorithm for high dynamic range infrared imaging system

Abstract

The infrared imaging system with high dynamic range is one of the most prime candidates in the area of quantitative infrared radiometry and thermometry applications. As the foundation of the measurement processes, radiometric calibration is the inception procedure which will be studied emphatically in this paper. Conventional radiometric calibration algorithm is not suitable for high dynamic range infrared imaging systems that requires the flexibility of adjusting the integration time and transmittance according to characteristics of the detected target. Unfortunately, fixed calibration coefficients will inevitably arouse the deterioration of the calibration accuracy in the case of variable integration time or the transmittance. For the purpose of solving above issues, effects of integration time and transmittance on calibration are analyzed in detail. A modified calibration algorithm considering the integration time and transmittance is proposed to compensate the calibration error caused by the change of these two factors. Experiments confirm that the accuracy of the proposed calibration algorithm can reach about 1 % under the conditions of varying integration time and transmittance, which is effectively applicable to high dynamic range infrared imaging applications.