A technical realization to inspect specular surfaces based on an imita
tion of the human visual inspection process is presented. The human ob
server does not look at the surface itself but at the environment refl
ected by the surface and analyzes the distortions. To automate this vi
sual approach and to extend it to a quantitative measurement method, a
CCD-camera looks at the reflected image of an illuminated, programmab
le LC-Display. With a sequence of patterns on the LCD and by means of
inverse ray tracing the surface relief can be reconstructed. In contra
st to the method of fringe projection, which is locally sensitive main
ly to the absolute topography, the reflexion method is particularly se
nsitive to the gradient of the surface.