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Proceedings Paper

Moire image overlapping method for PCB inspection designator
Author(s): Rang-Seng Chang; Yeu-Jent Hu
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Paper Abstract

Computer pattern recognition has been expanding its application in various fields. Its application in printed circuit board (PCB) inspection, for example, will accordingly reduce the requirement of manpower as well as the error rate, if equipped with adequate accessories; real time processing can then be implemented with defect locating feature. The design philosophy of this system is focused on how to establish a complete PCB inspection methodology with an error indication for a more effective amending process. The algorithm of this system is as follows: first, use the CCD camera to scan the PCB under inspection, then compare it with the correct one, which has already been stored in the computer memory, and compare the results. If any error exists, then a `+' will be marked on the defect spot from the computer, and overlapping will be executed via a computer-controlled zooming LCD (liquid crystal display) overhead projector. The `+' mark can specify the defect spot clearly. The size and the position of the overlapping image with the tested PCB will be exactly one to one. The optical distortion error is corrected by computer program using the moire and optical analysis method.

Paper Details

Date Published: 1 December 1991
PDF: 4 pages
Proc. SPIE 1567, Applications of Digital Image Processing XIV, (1 December 1991); doi: 10.1117/12.50816
Show Author Affiliations
Rang-Seng Chang, National Central Univ. (Taiwan)
Yeu-Jent Hu, National Central Univ. (Taiwan)


Published in SPIE Proceedings Vol. 1567:
Applications of Digital Image Processing XIV
Andrew G. Tescher, Editor(s)

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