Evaluation of local spatial frequencies on fringe patterns using statistical fringe processing

Abstract

Ubiquitous in coherent metrology, fringe patterns are processed traditionally using tedious manual evaluation and the presence of noise critically hampers fringe processing. A statistical fringe processing algorithm has been reported to be sensitive to spatial frequencies and the technique was utilized in various applications.  In this work, the application of the statistical algorithm in locating and bounding regions of phase maps with different spatial frequencies is investigated.  Results show that the algorithm is successful for frequency-dependence along both one dimension and two dimensions and can also distinguish regions whose frequencies differ by only 1%. Furthermore, the algorithm is used in the analysis of experimentally obtained phase difference maps from a loaded refractive sample.  The localization of different spatial frequencies has applications in techniques that utilize non-global filters.