Sensitivity vector map retrieval in digital holography used for shape measurement

Abstract

The freeform and aspheric measurement in the industry is rather cumbersome. This situation led us to the decision to start the development of the metrology tool offering the measurement of grinded (diffusive) and polished (specularly reflecting) surfaces with arbitrary geometries and with the necessary fiducials. We proposed digital multiwavelength multidirectional holographic contouring with phase shifting. Recently we redesigned our system heavily e.g we use 16 independent illumination directions, we use new PSI algorithm, etc. The factor strongly influencing the method precision is the sensitivity vector field knowledge over the whole measured area. We proposed the method of the sensitivity vector map retrieval based on controlled movement and recording of the measured part with the data evaluation. The proposed method has been tested recently. The method fundamentals, experimental setup and the results are presented in this paper.