Adaptive algorithm for estimating fringe orientation of speckle patterns

Fringe orientation is important information for processing and analysis of interferometry fringe patterns. It is useful to estimate fringe orientation. However when the signal to noise ratio of speckle pattern is unity, it is difficult to extract signal from single speckle pattern. In this paper, an adaptive algorithm for estimating fringe orientation of speckle patterns is proposed. This algorithm includes three steps: computing the local fringe width in a low precision, estimating fringe orientation with curved surface fitting and smoothing fringe orientation map. The experimental result show that this algorithm is efficient for speckle interferometry fringe patterns. Of course, this algorithm is suitable to the others of interferometry, such as conventional holographic and moire techniques.