Auto pick-up of fringe skeletons in ESPI displacement measurement

When the electronic speckle pattern interferometry (ESPI) is applied to the measurement of displacement fields, fringe skeletons are corresponding to the contours of displacement. Therefore, how to pick up fringe skeletons precisely is the key problem in ESPI displacement measurement. Based on fringe refinement algorithm, this paper puts forward a method to pick up fringe skeletons. After the skeletons are thinned, they are amended to eliminate bridgings and branches, and are fitted to a group of smooth, unit width lines. If methods in this paper are applied, the auto pick up of fringe skeletons can be done precisely and rapidly.