Calibration method for angular measurement of moire patterns

In this paper, a high-accuracy calibration method for angular measurement of deformed and curved Moire patterns, based on template matching algorithm, is presented. We report a feasible and accurate method, based on Talbot interferometry and Moire deflectometry, to measure long focal-length lenses. Theoretical analysis indicates that the precision of this method is mainly influenced by the angle of Moire patterns. However, it's difficult to obtain high-accuracy angle of Moire patterns, since the Moire patterns derived from experiment are constantly deformed or curved. We demonstrate a method, based on template matching algorithm, to calibrate deformed and curved Moire patterns, thus their angle can be calculated fast and accurately in sub-pixel domain. Numerical analysis and simulation prove that the method mentioned above demonstrates high precision and stability, and experiment results show that the accuracy of the long focal lengths measurement is improved obviously.