3D thermal mapping of smoldering coal gangue pile fires using airborne thermal infrared data

Abstract

Smoldering coal gangue pile fires pollute the air, soil and groundwater severely. Physical and chemical explosions between water and fiery coal gangue may occur, resulting in a large number of casualties. Recognizing and delineating the scope of coal gangue pile fires is a precondition and top priority for firefighting efforts. The present study employs a 3D thermal imaging methodology based on Unmanned Aerial Vehicle (UAV) remote sensing data. Thermal infrared oblique photogrammetry is used to collect overlap-high thermal infrared images of smoldering fires. A batch preprocessing software is developed to standardize the temperature range, temperature distribution mode and color scale of all thermal infrared images, improving feature point identification accuracy. The elaborate delineation and accurate identification of 3D temperature field are realized by feature point matching and texture mapping. The method was used to build the 3D temperature model and visualize the scope of the coal gangue pile fires in the 1360 bench, viewing bench and belt corridor of the Anjialing Open-pit Mine in China. The 3D thermal models accurately characterize the distribution of the smoldering fires, providing firm support and guidance for the firefighting efforts.