Model-Based Deflectometric Measurement of Transparent Objects

The measurement of the entire 3-dimensional geometry of a transparent object like a lens is a challenging task for established measurement techniques. In addition to some process-specific drawbacks, like the long measurement time for scanning techniques or the small robustness for interferometric approaches, many optical measurement techniques suffer from the fact that they have to measure the front and rear surface of such a specimen in reflection, which implies some major drawbacks: