Electronic Speckle Pattern Interferometry with Optimum Image Extraction for Deformation Measurement under Environmental Disturbance

Abstract

A method for extracting optimum images from a large amount of speckle images is proposed for ESPI measurement under environmental disturbance. During the measurement of static deformation under environmental disturbance, optimum images which can make interference fringes are extracted from the speckle images before the image subtraction. The extraction is performed based on the evaluation of the highest speckle contrast in time series value. The validity of the method is investigated by experiments under the environmental disturbance coming from the floor. Results indicate that the extraction method is effective and it is possible to measure static surface deformation by ESPI without a vibration isolator under environmental disturbance.