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Video Thresholding for Automated Card Inspection

IP.com Disclosure Number: IPCOM000040248D
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Kishi, GT: AUTHOR [+2]

Abstract

A video inspection tool automatically inspects printed circuit cards to verify correct component lead insertion prior to soldering the card. Video thresholding is a technique used in a series of software analysis routines that take grayscale image data and process the data to determine the presence or absence of leads in a hole. The example described is a dual thresholding technique (which could be expanded to more levels). Typically, a thresholding lead analysis routine will scan a set of pixels where the lead is expected and compare all the pixels against a threshold used to determine whether the lead is there or not. Based on this comparison, a pass or fail decision is returned by the routine. The routines on the video inspection tool use a dual threshold to determine lead presence.

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Video Thresholding for Automated Card Inspection

A video inspection tool automatically inspects printed circuit cards to verify correct component lead insertion prior to soldering the card. Video thresholding is a technique used in a series of software analysis routines that take grayscale image data and process the data to determine the presence or absence of leads in a hole. The example described is a dual thresholding technique (which could be expanded to more levels). Typically, a thresholding lead analysis routine will scan a set of pixels where the lead is expected and compare all the pixels against a threshold used to determine whether the lead is there or not. Based on this comparison, a pass or fail decision is returned by the routine. The routines on the video inspection tool use a dual threshold to determine lead presence. The higher threshold (brighter value) is used to make a "hard" pass decision on the set of pixels; if one of the pixels is greater than or equal to the higher threshold, then the routine says that a lead is present in the hole. A second, lower threshold is also used. If the higher threshold is not met (and, therefore, no "hard" pass decision on the lead), the pixels are measured against the second threshold. If one of the pixels is greater than or equal to the lower threshold, then the routine returns a "soft" pass (or a "maybe" decision.) If none of the pixels is greater than, or equal to, the lower threshold, the routine returns a...