Absolute shape measurements using high-resolution optoelectronic holography methods

Characterization of surface shape and deformation is of primary importance in a number of testing and metrology applications related to the functional ity, performance, and integrity of components. in this paper, a unique, com pact, and versatile state-of-the-art fiber-optic-based optoelectronic holog raphy (OEH) methodology is described. This description addresses apparatus and analysis algorithms, especially developed to perform measurements of bo th absolute surface shape and deformation. The OEH can be arranged in multi ple configurations, which include the three-camera, three-illumination, and in-plane speckle correlation setups. With the OEH apparatus and analysis a lgorithms, absolute shape measurements can be made, using present setup, wi th a spatial resolution and accuracy of better than 30 and 10 mu m, respect ively, for volumes characterized by a 300-mm length. Optimizing the experim ental 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 particula r feature of this methodology is its capability to export the measurements data directly into CAD environments for subsequent processing, analysis, an d definition of CAD/CAE models. (C) 2000 Society of Photo-Optical instrumen tation Engineers. [S0091-3286(00)02601-5].