Multi-spectral light-field imager for ultra-high temperature measurement

We have developed a multi-spectral light-field (MSLF) imager for high-temperature measurements ranging from 973 K to 2973 K. By integrating an optical-filter-array (OFA) in front of the main lens, the MSLF imager can simultaneously capture both the spatial and spectral information of high-temperature objects. To achieve accurate measurements for ultra-high temperatures, we simulated the effects of wavelength selection on the intensity of MSLF images, so as to determine the optical parameters for different temperature ranges. An in-house MSLF imager was constructed and blackbody tests were conducted to verify the design. In blackbody experiments, 700-850 nm OFA was used for temperatures ranging from 973 K to 1673 K. And for temperature above 1673 K, the 500-650 nm OFA was employed. It is important to note that, except for the OFA, all other optical components remain unchanged. The experimental results indicate that the MSLF imager, equipped with 500-650 nm and 700-850 nm OFAs, can achieve a measurement accuracy better than 0.4% across a broad range of 973-2973 K. Furthermore, a 50% increase in measurement accuracy can be achieved with the proposed wavelength calibration method.