Adaptive lighting for inhomogeneous reflectivity compensation in applications for 3D shape measurements

Surface 3D reconstruction is a topic of great relevance and it has a wide range of applications in many fields such as mechanics, bioengineering and arts. Nowadays optical systems for 3D contouring such as those based on structured light projection are becoming more and more widespread. The possibility to get shape information without any contact with the object, in fact, is a great advantage in some fields such as, for example, cultural heritage. For this class of objects, however, the issue connected with inhomogeneous reflectivity must be taken into account. Due to the different level of reflectivity, in different areas of the object, it comes out that the contrast of the projected pattern changes and, as a direct consequence, the achievable accuracy can change from part to part. In this paper, a study on the possibility to implement an adaptive lighting algorithm is performed allowing to adapt illumination in order to compensate the local inhomogeneities in terms of surface reflectivity.