Document Type

Conference Proceeding

Publication Title

Proceedings of SPIE - the International Society for Optical Engineering


A problem common to automated assembly in manufacturing or in automated docking of spacecraft is angular and lateral alignment of components. A hybrid video system utilizing both conventional imaging and 3-D video moiré has been developed to automatically align a test target with three translational and two rotational degrees of freedom. Alignment was demonstrated via computer controlled translation and rotation stages. The video moiré system is operated in an error map mode, in which a structurally illuminated reference surface is used to chromakey the image of an identical structurally illuminated alignment target. The output is a moiré image generated by the misalignment of the two surfaces; further processing indicates the degree and direction of the misalignment. The translation alignment error signals (x, z, zoom) are generated by conventional image processing operating on filtered or non-structurally illuminated images. In one design, translational and rotational alignments are handled by separate processors controlled by a single host, and might use synthesized images as reference: the off center and smaller image of a laterally misaligned and distant target can be zoomed and centered with respect to a synthetic image. In another design, the synthetic image is passed to the angular alignment program while translational alignment takes place, so that coarse angular alignment can proceed essentially in parallel with the lateral and range alignment. Thus both sequential and parallel processing can be utilized to solve the alignment problem.



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