Fireball symmetry and its influence on perspective error from thermography data

Thermography uses high-speed color cameras to perform two-color pyrometry for measuring spatially resolved surface temperatures of condensed phases. One application is to investigate the thermal evolution of particles within fireballs, but data analysis is affected by emissivity and optical density. Fireball dynamics exhibit large variations in both properties across space and time, while diagnostics measure the line-of-sight radius of a maturing fireball, raising the question: does thermography accurately represent temperature distributions regardless of spatial perspective? Here, fireballs are observed at two 90° perspectives. Every frame of data is categorized based on symmetry, then compared using the median temperature difference. Symmetric flame profiles show higher congruity in global median temperature, whereas asymmetric flames produce varying optical density profiles leading to larger differences between perspectives. Methods to correct perspective errors are discussed.