Color crosstalk correction for synchronous measurement of full-field temperature and deformation

Abstract

Synchronous measurement of temperature and deformation at elevated temperatures based on the noncontact optical method can be achieved through the allocation of channels R, G, and B for a color camera. Channels R and G are used for the radiation-based temperature measurement, while channel B is adopted for the deformation measurement. However, the existence of color crosstalk, which is mainly caused by the color camera's spectral response and the use of the narrow-band filtering technique, has a significant influence on the accuracy of temperature and deformation calculations. In this work, the color crosstalk effect in high-temperature optical imaging is analyzed, and a crosstalk correction algorithm based on grayscale calibration is performed on the different color channels (channels R, G, and B) of the color image. By solving the calibration equations, three corrected color channels are generated for a high-precision temperature and deformation calculation. A flame heating experiment of a C/SiC material up to 1100 °C is carried out to validate the applicability accuracy of the proposed method. The results show that the proposed method can effectively eliminate the color crosstalk between different channels and provide a non-contact, full-field, and synchronous measurement of temperature and deformation with higher accuracy than the existing methods.