Research on temperature distribution of combustion flames based on high dynamic range imaging

The imaging-based three-color method is widely used in the field of non-contact temperature measurement of combustion flames. In this paper, by analyzing the imaging process of a combustion flame in detail, we re-derivate the three-color method by adopting a theory of high dynamic range imaging. Instead of using white balanced, gamma calibrated or other algorithms applied 8-bit pixel values, we use irradiance values on the image plane; these values are obtained by combining two differently exposed raw images into one high dynamic range irradiance map with the help of the imaging system's response function. An instrumentation system is presented and a series of experiments have been carried out, the results of which are satisfactory.