This proposal will investigate the use of Moire' interferometry in conjunction with optical Fourier transforms in a machine vision system for application to inspection tasks. The suitability of Fourier sampling in the interpretation of Moire' fringes will be investigated and the robustness of the system using different test objects under different conditions will be tested. Current machine vision systems are primarily based on video signal processing by digital computer. The amount of information that must be digitally processed for each test object is large, thus processing is either slow or requires expensive hardware. The proposed method employs optical signal processing in both the Moire' and Fourier portions of the system, thus greatly reducing the digital processing requirements. The proposed techniques are inherently inexpensive and very fast, and should be robust in production situations. The research plan in this Phase I includes: Generation of well defined Moire' patterns and investigating these with the Moire'/Fourier system. Testing the system on good and bad versions of test objects, such as stamped metal part with dent or improper curvature, smooth metal part with scratches, turned metal part with nicks or out-of-roundness, and injection molded part with extraneous flashing. Investigate the discrimination capability for moving objects at typical production speeds. Investigate position tolerance by moving the test object in the field of view. This research should determine which applications are suited to Moire'/Fourier inspection and what kind of inspection discrimination can be realized, and will provide direction for further phases. Follow-on phases are planned which include investigating a table top set up of optimum hardware configuration to handle the largest range of inspection parameters, followed by commercial development of a system. This research should lead to an efficient machine vision system which is expected to contribute to reducing manufacturing costs, improving product quality and gaining competitive strength.
