Research on calculation of surface irradiance for infrared extended sources based on CUDA parallel speedup.

To correct the error caused by uneven distribution of target surface irradiance in the measurement of emissivity by the irradiation reflection method, a progressive method for calculating the surface irradiance for infrared extended sources was proposed, and its CPU-GPU heterogeneous operation speedup was realized based on the compute unified device architecture (CUDA). The proposed method calculated the radiation transfer at the scale of small surface sources while considering the multiple reflections between the sources, which better reflected the actual physical condition. The CUDA-based parallel speedup enabled calculation within a few seconds even for several data levels, which facilitated pixel-by-pixel analysis of surface emissivity measurements. In addition, the effectiveness of the proposed calculation method was analyzed by adjusting multiple scene parameters. The advantage of the proposed method was analyzed by comparing it with several irradiance calculation methods in terms of the result and correction effect on emissivity measurements. The speedup effect of CPU-GPU heterogeneous operation was analyzed by adjusting the calculation parameters. The results revealed that the proposed method could effectively calculate the irradiance distribution on the target surface regardless of the distance between the radiation sources, and the calculation consumed a very short time. It could correct the emissivity measurement errors caused by uneven irradiance and was of great significance to further improving the accuracy of emissivity measurements by the irradiation reflection method.