Measurement of three-dimensional displacement fields and shape using electronic speckle photography

A stereoscopic electronic speckle photography system is presented that detects 3-D displacement fields or object shape with subpixel accuracy. The system is all electronic, and data are stored, results are presented, and calculations are performed in a PC computer. The expected standard deviation of measurements of small deformations are about 0.001% of the object size for in-plane measurements and about 0.006% of the object size for the out-of-plane component, when white light speckles are used.