High Precision Algorithms for 3D Objects Shadow Inspection in Partially Coherent Light

Abstract

As applied to the dimensional inspection the peculiarities of 3D objects image formation with clear shadow projection under their illumination by quasi-monochromatic partially coherent light based on the constructive theory of 3D objects formation using a model of equivalent diaphragms are studied. Two threshold algorithms for determining the position of 3D objects geometric boundaries under their inspection by optical shadow method according to their thickness as well as the light source angular size and the projection system aperture diaphragm are developed. These algorithms are based on the application of true (calculated) threshold or standard one using the corrective component to threshold. It has been shown theoretically and experimentally that their use can significantly improve the measurement accuracy of extended objects. The obtained results under the development of measuring systems for industrial inspection of ceramic details allowed us to reduce the measurement error.