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Proceedings Paper

Nonreference Optical Inspection Of Complex And Repetitive Patterns
Author(s): Warren M. Sterling
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Paper Abstract

A system designed for non-reference real time optical inspection and analysis of complex or repetitive patterns is described. The primary application of the system has been the inspection of etched and plated patterns. For printed wiring board (PWB) inspection, the system can inspect a 20 x 24 inch board in approximately four minutes, utilizing one mil ( .001 inch) imaging. resolution. Imaging resolution of 0.5 mil (.0005 inch) can be achieved. The system employs a. non-reference inspection technique in that it does not compare the article under test to an article known to be good. Rather, the acceptability criteria are based on design rules and material parameters. Video rate image analysis is attained by initial encoding of the video data, and utilization of analysis packages which operate directly on the encoded data. System implementation lends itself to easy modification for diverse patterns and testing criteria. This paper will discuss all aspects of the system including the linear CCD array based sensor and scanner assembly, hardware and firmware encoding of the video data, and the defect detection technique. Application examples are presented, including insection of inner layers of multi-layer PWB's, inspection of plated repetitive structures, and optical character recognition (OCR)

Paper Details

Date Published: 12 November 1981
PDF: 10 pages
Proc. SPIE 0281, Techniques and Applications of Image Understanding, (12 November 1981); doi: 10.1117/12.965746
Show Author Affiliations
Warren M. Sterling, Xerox Corporation (United States)

Published in SPIE Proceedings Vol. 0281:
Techniques and Applications of Image Understanding
James J. Pearson, Editor(s)

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