An integrated thermal and visual camera system for 3D reconstruction

Abstract

In this article a new approach for 3D reconstruction of thermal scene is presented. The system consists of two cameras: thermal and visual. The reconstructed object is observed from at least two different viewpoints by the two cameras. The two images either from thermal camera or visual one constitute a stereoscopic set. By means of corresponding feature points extracted from the pair of either thermal or visual images, the relative position of the two viewpoints is evaluated. Then the images are rectified and the standard stereo reconstruction is performed on either thermal or visual images depending on the scene conditions, i.e. depending on the number and quality of feature points extracted from the thermal and visual pairs. The relative position of the two viewpoints is established only up to some scalar factor. To establish the relative position with respect to some metric value two approaches were applied: (a) based on a known distance between two points in 3D space and (b) based on an additional approximate 3D reconstruction of a given point by the thermal and visual camera pair treated as a stereoscopic set. The designed application which performs the calibration of the system and 3D scene reconstruction is described and the obtained results are presented.