Detection of Optical Fringes Parameters with Global Direction Metric

摘要

A global direction metric method based on Fourier-polar transform is proposed in this paper, which calculates theglobal fringe direction according to the directional distribution of intensity from the power spectrum of fringe pattern. Byintroducing polar coordinate transform, the rotation of power spectrum is transformed into translation component, whichcan make the calculation process simple and fast. Then the original image is projected along the global fringe directionand the mean value of pixel gray is calculated. Also, the fringe pitch can be calculated from the projection curve close tocosine distribution. This detection method of optical fringe parameters uses overall information of the image, and holdsgood adaptability and robustness to noise and degraded image. Moreover, without any pre-processing operations such assmoothing filter and threshold segmentation is required in this method. It can directly detect two parameters of globalfringe direction and fringe spacing, which is of great significance for quantitative analysis of fringe image.