Alignment of vectorial shearing interferometer using a simplerecognition algorithm

摘要

The vectorial shearing interferometer includes a pair of wedge prisms as a shearing system. Perfect alignment of theshearing system is crucial for the optimal detection and analysis of asymmetrical wave fronts. This paper describes arecognition algorithm for optical misalignment detection and prisms orientation based in the intensity pattern obtained inthe calibration process. The key of the present algorithm is the comparison of a reference intensity pattern, against asheared interferogram that depends on the wedge prism position. First, an optimum phase only filter is obtained from aset of reference images with the objective to discriminate between different phase changes. Then, the optimal filter isused in a digital correlator, which results in a simple and robust calibration system.