Velocity Measurement with Speckle and Speckle-like Photography

Abstract

The criteria for image structure and film properties for velocity measurement by speckle-pattern photography are discussed. Even with low intensity light sources, holographic film is unnecessary, and Plus-X-Pan film will record sufficient detail (in multiple exposures if necessary) to form diffraction pattern fringes. Speckle photography techniques can also be applied to appropriately prepared, incoherently illuminated surfaces, so long as the camera image has the correct speckle-like granular structure. Experiments verifying these ideas are described.