Three dimensional temperature estimation of a fire plume using multiple longwave infrared camera views

In order to determine true radiometric quantities in intense fires a three dimensional (3D) understanding of the fire radiometric properties is desirable, e.g., for estimating peak fire temperatures. Imaging pyrometry with a single infrared camera view can provide only two dimensional path-averaged radiometric information. Multiple camera views, however, can form the basis for determining 3D radiometric information such as radiance, emissivity, and temperature. Analytically the fire can be divided into sub-volumes in which radiometric properties are assumed roughly constant. Using geometric and thermal equilibrium relationships between the fire sub-volumes, together with LWIR camera imagery acquired at multiple carefully defined camera views, radiometric properties of each sub-volume can be estimated. In this work, initial proof-of-principle results were obtained by applying this analysis to sets of LWIR camera imagery acquired during intense (2500 – 3000 K) fires. We present 3D radiance and temperature maps of the fires obtained using this novel approach.