For the past two decades, the need for three-dimensional (3-D) scanning of industrial objects has increased significantly and many experimental techniques and commercial solutions have been proposed. However, difficulties remain for the acquisition of optically non-cooperative surfaces, such as transparent or specular surfaces. To address highly reflective metallic surfaces, we propose the extension of a technique that was originally dedicated to glass objects. In contrast to conventional active triangulation techniques that measure the reflection of visible radiation, we measure the thermal emission of a surface, which is locally heated by a laser source. Considering the thermophysical properties of metals, we present a simulation model of heat exchanges that are induced by the process, helping to demonstrate its feasibility on specular metallic surfaces and predicting the settings of the system. With our experimental device, we have validated the theoretical modeling and computed some 3-D point clouds from specular surfaces of various geometries. Furthermore, a comparison of our results with those of a conventional system on specular and diffuse parts will highlight that the accuracy of the measurement no longer depends on the roughness of the surface.
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.
Because of the difficulty of dealing with specularity of several surfaces, few methods have been proposed to measure
three-dimensional shapes of specular metallic objects. In this paper we present an application on this kind of material of
an approach called "Scanning From Heating". This approach has been developed initially for 3D reconstruction of
transparent objects. This article presents an application of the working principle of SFH method on material with high