Multispectral imaging and channel allocating for synchronous measurement of temperature and deformation over a wide temperature range.

Synchronous measurement of temperature and deformation over a wide temperature range at elevated temperatures is essential for evaluating material performance and guiding the design of high temperature structural material. However, the significant variations in radiation intensities across different temperatures present challenges in obtaining high quality experimental images, often compromising measurement precision or causing measurement failure. To address this issue, we propose a novel multispectral channel selection method, to our knowledge, based on sensitivity calculations, enabling synchronous temperature and deformation measurements using a multispectral camera over a wide temperature range. This method allows the selection of three channel combinations to accommodate temperatures ranging from 800 K to 2000 K. Additionally, we calibrated a compensating light source and characterized the spectral properties of a typical specimen. Validation experiments using oxy-propane flame heating of a C/SiC specimen confirmed the reliability and effectiveness of the proposed method, demonstrating its ability to maintain consistent optical parameters across the temperature range. Compared to traditional approaches, our method significantly enhances measurement accuracy and extends the measurable temperature range, providing a robust solution for performance testing and service life evaluation of materials and structures under extreme temperature conditions.