High dynamic range infrared thermography by pixelwise radiometric self calibration

A procedure is described where the response function of each pixel of an InSb detector is determined by radiometric self-calibration. With the present approach no knowledge of the spectral characteristics of the IR system is required to recover a quantity which is linear with the incident irradiance of the object. The inherent detector non-uniformity is corrected on the basis of self-calibrated scaled irradiance. Compared to the standard two-point non-uniformity correction procedure – performed with the detector signal – only two NUC-tables are required for arbitrary integration times. Images obtained at various exposures are fused to a single high dynamic range image. The procedure is validated with synthetic data and its performance is demonstrated by measurements performed with a high resolution InSb FPA.