Fiber-optic measurement of the deformation field on a remote surface using numerically processed white-light speckle

Fiber optics provides a means of making optical measurements on remote or otherwise inaccessible surfaces by transmitting reflected light from that remote surface to an appropriate place and/or system for recording and analysis. In this study fields of artificially generated random speckle on the surface of a deformable test subject are transmitted at various magnifications through a coherent multimode fiber optic bundle (MMB) to a vidicon camera-digitizer system (VCD) where they are recorded for successive states of surface deformation. These results are then numerically correlated to provide a measure of that surface deformation at a number of different locations for each pair of recorded speckle fields.