Method of Evaluating Image Correlation with Speckle Patter

摘要

An image correlation for images having speckle pattern is evaluated. Modulation transfer function (MTF) curves of speckle-pattern images captured at different times are figured out. Whether a correlation value between the MTF curves meets a threshold is checked. If the correlation value is smaller than the threshold, speckle-pattern images are re-selected for re-figuring out the MTF curves and the correlation value. Thus, error of strain and displacement for digital image correlation owing to blurring images of the on-moving target object is figured out; calculation time of the digital image correlation is reduced; and accuracy on measuring physical parameters of the target object before and after movement is improved for digital image correlation.

主权项

1. A method of evaluating image correlation with speckle pattern, comprising steps of:
(a) capturing a First Speckle-Pattern Image and at least one Second Speckle-Pattern Image of a target object at different times, separately; (b) obtaining a first modulation transfer function (MTF) curve of said First Speckle-Pattern Image and obtaining at least one second MTF curve of said at least one Second Speckle-Pattern Image; (c) obtaining a correlation value between said first MTF curve and said at least one second MTF curve; and (d) finishing evaluating said correlation value between said first MTF curve and said at least one second MTF curve when said correlation value meets a threshold.