Active illumination for the segmentation of surface deformations

The segmentation of surface deformations like scratches or embossed patterns can be decisively supported by using several images taken under different illumination directions. To demonstrate this approach we present two applications-the segmentation of embossed letters and the detection of grains on grinding wheels-together with two illumination devices which aid in the development of such solutions. We address further the problem of (additive) shading and how at may be solved using conventional approaches based on `real´ or estimated reference images and as well as by artificial reference images obtained by a rendering approach using a model of the setup. Finally we give an outlook on the planning of illumination setups