Deflectometric Measurement of Specular Surfaces

The presented deflectometric method utilizes the surface under inspection as a mirror in a known surrounding and achieves a highly accurate measurement of gradient errors. The comparison of the measured imaging function with reference data allows a precise assessment of the surface quality. Since this approach mimics the inspection behaviour of humans, the results match the errors perceived by a human. However, it is often difficult to provide adequate reference data. A solution to this problem could be based on using CAD data of the part, which is often available from the product design process