Modelling the influences of technical surfaces on Phase Measuring Deflectometry

Phase Measuring Deflectometry (PMD) is a geometrical optics based, non-coherent, full-field metrology technique used for measuring specular surfaces. In a PMD system, camera, display and the surface under test are the three main components. With regards to the measurement uncertainty in PMD systems, the camera is best described and most thoroughly modelled, followed by the display with its nonlinearity and flatness deviation. However, the influences of the properties of technical surfaces on the measurement deviation still lacks detailed investigation. Technical Surface can be any surface at different stages of manufacturing but in our work only the reflective surfaces with periodic structures are considered. Generally, these technical surfaces introduce errors due to the local structures into the phase measurement, contributing towards the subsequent slope and shape measurement errors. In this paper, we demonstrate the influence of these properties of surfaces manufactured by high precision diamond turning on phase measurement. A simulative approach for assessing these effects is presented.