Automatic Inspection for Printed Wiring
Original Publication Date: 1982-Oct-03
Included in the Prior Art Database: 2007-Mar-28
Software Patent Institute
Thibadeau, Robert: AUTHOR [+4]
Automatic Inspection far P tinted Wiring . o o z R 1 6
Automatic Inspection far P tinted Wiring .
o o z ~ R 1 6 ~ ~
k f;ricdlnan and John scto'
COMPUTER SClENCE DEF,4jqTa,l~jq~
The Robotics Institute Carnegie-Mellon University
Pittsburgh, Pennsylvania 15213
Copyright @ 1983 Carnegie-MelIon University
Paper presented at The Institute for Interconnecting and Package Electronic Circui Fail Mccting, San Diego, CA, October 3,1982. .
'westinghouse Defense and Electronic Systems
Table of Contents
2. Guidelines for an lnspection Station
3. Types of Inspection Stations
4. How Design Rule Systems Work, and Don't Work
5. What happened to Truly Automatic lnspection Stations?
6. Flexible if not Ideal Stations
Cooperation betwcen thc Robotics Institute and Wcstinghouse Corporation has resulted in the devclopmcnt of guidelines, or specifications, for a PWB inspection station. These gui clines are presented in
this technical report. Although PWB inspection stations primarily serve quality cont 01 functions, they hold great potential in serving functions of process control. Discussed in this rcport is hat can reasonably be expected from state-of-the-art P WB inspection aids, types of stations and how they wolk.
I. Int reduction 1
Twenty years ago academic literature on computer vision contained many \computer analyses of images of printed circuit boards. Even the most recent textbooks on image prbcessing will illustrate
several algorithms on pictures of printed circuits. The algorithm shows how detect a defect in a printed circuit from the visual image of it. Every time. (of course), the algorithm /Eucceeds in detecting the defect. But for all these twenty years, and all those examples of defect dete tian, there has yet to be a successful commercial product for the visual inspection of printed circuits machine. Perhaps the printed circuit industry lacked incentive for automated visual inspection. B now there is a need, and researchers are learning that automated printed circuit board inspectionlis a hard problem to solve.
Figure 1 provides an example of a printed circuit -- in this case an image taker( at low magnification to give the idea of the patterns on a printed circuit board. The pattern is in copp+, and the reader may note the image from the copper on the...