Today, with quality becoming increasingly important, each product requires three-dimensional in-line quality control. On the other hand, the 3D reconstruction of transparent objects is a very difficult problem in computer vision due to transparency and specularity of the surface. This paper proposes a new method, called Scanning From Heating (SFH), to determine the surface shape of transparent objects using laser surface heating and thermal imaging. Furthermore, the application to transparent glass is discussed and results on different surface shapes are presented.

International audienc

International audienc

International audienceMany experimental techniques and many com- mercial solutions have been proposed to realize non-contact 3D digitization of industrial objects. Unfortunately, the per- formances of active 3D scanners depend on the optical prop- erties of the surface to digitize. That is why the results obtained by active 3D triangulation on specular or transparent surfaces are not as good as those obtained on diffuse surfaces. In this paper, we present the developments we have realized to address highly reflective metallic surfaces. These develop- ments are based on the extension of a technique, called "Scan- ning from heating" and initially dedicated to glass material. In comparison to conventional active triangulation techniques that measure the reflection of visible radiation, we measure here the thermal emission of a surface, which is locally heated by a laser source. We describe in this paper the successive steps we have followed to adapt Scanning From Heating to metallic materials, to evaluate the performances and finally to develop an operational prototype

In this Letter, a vision-based remote sensing methodology is proposed to measure the topography of weld pool surfaces from one single view. Thermal radiations emitted by the hot liquid metal at a wavelength within the arc plasma blind spectral window are acquired by a wavefront division polarimetric system. The refractive index of the liquid metal and the topography of the weld pool surface are inferred from the polarimetric state of the thermal radiations.

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. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE).

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