Digital speckle shearing interferometry use of linear CCD scanning

Abstract

Digital speckle shearing interferometry is an optical, non-contactive and non-destructive method widely used for the stress and strain analysis of objects. In this paper, linear CCD, instead of area CCD arrays, is presented to record large area speckle shearing interferogram. Digital speckle shearing interferometry by use of linear CCD scanning can be effectively used to measure the out-of-plan deformation of the objects and get a wide filed of view in continuous scanning imaging. Especially for the objects with a wide range, it's very convenient to get the whole speckle shearing interferogram in one time. In the paper, large area interferograms with 3.5cm×3.5cm (5000×5000 pixels) pre-and-past loading are recorded by using linear CCD and processed with correlation algorithm and median filter. The experimental results show that the proposed method is feasible in the digital speckle shearing interferometry and have a great advantage in the measurement of objects with large size compared with general area CCD.