Electronic speckle pattern interferometry using digital image processing techniques

An application of digital image processing techniques to electronic speckle pattern interferometry (ESPI) is described. A special digital facility with a large frame memory for processing a TV image is developed, allowing one to perform precise and flexible operations such as subtraction, summation, and level slicing. As compared to analog techniques, digital image processing techniques facilitate the generation of high contrast fringes. The advantages of the special digital facility in ESPI are discussed on the basis of the experimental results.