Focused light-field multispectral radiation thermometry with enhanced spatial resolution

Accurate temperature measurement in high-temperature environments is essential for applications such as combustion diagnostics and turbine systems. Visible-band multispectral thermometry offers improved robustness against gas absorption compared to infrared methods, but conventional approaches are limited by system complexity or low spatial resolution. In this work, we propose a focused light-field multispectral radiation thermometry (FLF-MRT) method that enables single-shot acquisition of spatial and spectral information. By reallocating the sampling budget between spatial and angular dimensions, the proposed system enhances spatial resolution while preserving high measurement accuracy. Experimental results over the temperature range of 1200–1600°C demonstrate that the spatial resolution is improved from 0.096 mm/pixel to 0.024 mm/pixel, corresponding to a fourfold increase, while maintaining a relative temperature error below 0.5%. The proposed approach provides a compact and robust possibility for high-resolution temperature measurement.