1 February 1991 Image registration for automated inspection of 2-D electronic circuit patterns
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Proceedings Volume 1384, High-Speed Inspection Architectures, Barcoding, and Character Recognition; (1991) https://doi.org/10.1117/12.25305
Event: Advances in Intelligent Robotics Systems, 1990, Boston, MA, United States
An image registration approach for inspection of 2D electronic circuit patterns is described. The approach which coisists of an offline procedure and a runhime procedure has been validated on a prototype inspection system. The offline procedure selects and sorts registration features from CAD generated reference data according to a set of prespecified priority selection rules. Preference is given to features expected away from the center of the image since they represent potential distortions better. The size of windows searched during runtime to detect features is ohtamed from the maximum expected system errors and tolerances in part manufacture. To prevent spurious detection during runtime the ofiline procedure selects a feature if no other CAD feature intersects its window The runtime procedure detects edges and measures their image location to suhpixel accuracy within their respective search windows. Edges are detected by authenticating zero-crossings of a second-order differential operator applied to the profile of each search window. Registration is conducted on points composed by averaging the measured location of opposite polarity edges of the same object type and size. This reduces any bias introduced by the edge incasurement technique and prevents offsets that would otherwise be introduced by variations in circuit pattern dimensions. To minimize the likelihood of spurious edge detection (e. g. an edge detected on a defect) the dimension demarcated by the opposite polarity edge pair is monitored. After a significant number registration features have been detected the runtime procedure finds the parameters that transform pixels into CAD reference data coordinates and vice versa. Good results have been obtained in a prototype inspection system.
© (1991) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Arturo A. Rodriguez, Jon R. Mandeville, "Image registration for automated inspection of 2-D electronic circuit patterns", Proc. SPIE 1384, High-Speed Inspection Architectures, Barcoding, and Character Recognition, (1 February 1991); doi: 10.1117/12.25305; https://doi.org/10.1117/12.25305

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