Fiber optic based laser optoelectronic holographic system for shape measurements

Abstract

Characterization of surface shape and deformation is of primary importance in a number of test and metrology applications related to the functionality, performance, and integrity of components. In this report, a unique, compact, and versatile state-of-the-art fiber optic based laser optoelectronic holography (OEH) method is described. This description addresses apparatus and analysis algorithms developed to perform measurements of absolute surface shape and deformation. The OEH can be arranged in a number of configurations, including three-camera, three-illumination, and in-plane speckle correlation setups. With the OEH apparatus and analysis algorithms, absolute shape measurements can be made, using present setup, with an accuracy of better than 10 µm for volumes with a length of 300 mm. Optimizing the experimental setup and incorporating equipment with superior capabilities (as it becomes available) can further increase accuracy. The distinguishing feature of this method is the capability to export data directly into computer aided design (CAD) environments for processing, analysis, and definition of computer aided engineering (CAE) models, including determination of differences between the CAD models and actual components.