Absolute shape measurements using high-resolution optoelectronic holography methods

Characterization of surface shape and deformation is of pri- mary importance in a number of testing and metrology applications re- lated to the functionality, performance, and integrity of components. In this paper, a unique, compact, and versatile state-of-the-art fiber-optic- based optoelectronic holography (OEH) methodology is described. This description addresses apparatus and analysis algorithms, especially de- veloped to perform measurements of both absolute surface shape and deformation. The OEH can be arranged in multiple configurations, which include the three-camera, three-illumination, and in-plane speckle corre- lation setups. With the OEH apparatus and analysis algorithms, absolute shape measurements can be made, using present setup, with a spatial resolution and accuracy of better than 30 and 10 mm, respectively, for volumes characterized by a 300-mm length. Optimizing the experimental setup and incorporating equipment, as it becomes available, having su- perior capabilities to the ones utilized in the present investigations can further increase resolution and accuracy in the measurements. The par- ticular feature of this methodology is its capability to export the measure- ments data directly into CAD environments for subsequent processing, analysis, and definition of CAD/CAE models. © 2000 Society of Photo-Optical Instrumentation Engineers. (S0091-3286(00)02601-5)