MEASUREMENT OF THE DISPLACEMENT DISTRIBUTION BY SPECKLE PHOTOGRAPHY USING A BSO CRYSTAL

The use of Bi12SiO20 crystal plates for recording media of specklegrams in speckle photography enables one to measure the distribution of in-plane displacement on a rough surface of an object in situ and in quasi real time. For the purpose of measuring the distribution of any in-plane displacement in quasi real time by speckle photography using a BSO crystal plate, the dependence of the visibility of Young's fringes on the readout beam diameter for specklegram and the magnitude of the object displacement has been investigated. The fact is cleared that the visibility of Young's fringes depends on the number of speckles consisting of a Young's fringe, which is decided by the ratio of the displacement magnitude to the readout beam diameter. © 1990.