Study And Application Of Key Knowledge In 3D Measurement System Based On Projected Grating Method

The purpose of blade measurement system is to measure 3D surface of all kinds of blades. Through the comparison of the theoretic data and the measured data, the windage between the measured blade and the designed blade is judged to direct the manufacture of blades.In measurement of three-dimensional object shapes using projected grating method, the height of each point of the measured object is obtained through the processing and analysis of the stripe images. In the article, we mainly study the phase-shifting technique and the phase unwrapping technique. In accordance with the phase-shift miscalibration and detector nonlinearity, the error-compensating phase-shifting algorithms based averaging technique are proposed. And in order to solve the problems brought by traditional linearity scanning unwrapping algorithm, which leads to incorrect phase unwrapping, a correlative region algorithm for phase unwrapping is developed. Finally, a kind of blade is measured to show that this system has high measurement precision.