Applications of light field technology in temperature field measurement: A review

Temperature field measurement is essential for aero-engine diagnostics, metal processing, combustion analysis, and other high-temperature applications. However, conventional contact sensors and traditional radiation thermometry are still limited by sensor disturbance, emissivity uncertainty, restricted optical access, limited view information, and calibration complexity under transient or optically complex conditions. Light-field imaging provides a complementary route for temperature measurement because it can record spatial and angular radiance information in a single exposure and can be further combined with spectral encoding for multi-wavelength acquisition. This review summarizes recent progress in light-field-based temperature field measurement. The reviewed studies are organized around two measurement problems: emissivity-dominated surface thermometry of opaque objects and tomography-dominated volumetric thermometry of semitransparent participating media. For each category, the measurement model, inversion algorithms, application evolution, and application-oriented system and algorithm selection are critically discussed. Finally, the value of light-field thermometry is summarized, and the major challenges and future directions are discussed, including spatial-angular-spectral trade-offs, principal uncertainty sources, multimodal diagnostics, advanced microlens technologies, physics-guided learning, and industrial robustness and long-term stability. This review provides a reference for the design, selection, and optimization of light-field thermometry systems for complex high-temperature environments.