Estimation of surface normal vectors based on 3D scanning from heating approach

The Scanning From Heating is a 3D scanning approach initially developed to realise 3D acquisition of transparent or specular surfaces. A laser source is used to create a local heating point. An infrared camera is used to observe the IR radiation emitted by the scene. The 2D coordinates of the heated point are computed in the 2D image of the camera. Knowing the parameters of the system (which are obtained by a previous calibration), the 3D coordinates of the point are computed using triangulation method. In this article we will present an extension of this technique. We propose here to analyse the shape of the hot spot observed by the IR camera, and, from the analysis to determine information on the local orientation of the surface at each measured point.