Infrared HDR image fusion based on response model of cooled IRFPA under variable integration time

The multi-exposure fusion method is an effective way to extend the dynamic range of the infrared focal plane array (IRFPA), but the traditional method doesn't take into account the impact of the integration time on every pixel's response function, thereby introducing nonuniform noises and affecting the fusion quality. Based on the traditional response model of an infrared detector, this article derives the relationship between the response function and the integration time by introducing new influence factors, and conducts verification experiments with MW and LW thermal cameras. The experimental results are consistent with the proposed model, which shows that, within the linear response range of the detector, the gain parameters of the pixels are independent of the integration time, and the offset parameters are approximately inversely proportional to it when the ambient temperature is determined. Meanwhile, based on the results, an infrared HDR image fusion method under a variable integration time is studied. The resulting images retain more details of the bright and dark areas of the scene, and the nonuniformity can be corrected to some extent at the same time. This proves that the model proposed in this paper is effective for extending the dynamic range of the IRFPA and has theoretical significance and practical value for further HDR thermal imaging research.