| 摘要 |
PURPOSE:To accurately extract a truly defective pattern only, by detecting candidate defective patterns from photographed patterns to extract a defective pattern from thereamong - double inspection structure. CONSTITUTION:A substrate pattern of a printed circuit board 1a is photographed by a camera means 1b and binary-coded with a binary-coding circuit 2. A feature extraction matrix circuit 3 defines a portion to be inspected of a printed circuit board pattern within a window and extracts candidates for defective pattern comprising singular patterns, corresponding to normal patterns included in the patterns available, and defective patterns. An output data of the feature extraction matrix circuit 3 is stored in a storage circuit and the stored data is applied to a detailed pattern inspection circuit 10 to perform precision detections of the patterns. Then, a defective pattern alone is extracted.
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