Tempered point clouds and octomaps: A step towards true 3D temperature measurement in unknown environments

Abstract

Although the generation of 3D temperature maps has become a frequently used technique, not only in search and rescue applications but also during inspection tasks, the remote measurement of a surface's true temperature is still a huge challenge. In this work, we face the problem of creating corrected 3D temperature maps in unknown environments without prior knowledge of surface emissivities. Using a calibrated sensor stack consisting of a 3D laser range finder and a thermal imaging camera, we generate Tempered Point Clouds (TPCs). With the help of the TPCs, we show how to perform a basic material classification, i.e. to make a distinction between metal and dielectric surface areas. For this purpose, we investigate measurements taken from different viewing angles. With the help of this approach, it is also possible to estimate corrected surface temperatures. The presented methods are evaluated making use of the OctoMap framework.