Automatic data reduction of certain holographic interferograms.

An automated technique is described that uses holographic interferometry to determine the translation of a diffusely reflecting rigid body. The photographs of the reconstructed virtual image of a double-exposed hologram were digitized. The CDC 6600 computer was used to process the reconstructed virtual image data by recording the number of fringes that moved over specified image points as the viewing direction of the hologram was varied. Contours were made by connecting all image points over which an equal number of fringes passed. A surface resolution (distribution of image points interrogated) of 0.0368 cm was used. By using this technique a 6.35-microm linear displacement of a 3.68-cm diam aluminum object was verified with an error </=4.3% over the entire object. It appears this technique can be extended to three-dimensional objects.