Gauging cylindrical parts

The way most people try to gauge shafts, screws and the like is with a collimated backlight and telecentric lens. At least I hope the backlight is collimated, because if it’s not the task gets even harder. But an article in Quality magazine, “When Quality Is a Matter of Life and Death” (August 6^th, 2012,) alerted me to another approach.

Now you might think this is yet another article about medical device inspection, but you’d be wrong. It is in fact about gauging bullets. And if you’re interested in such things, the Quality article has a lot to say about the development of more accurate rounds.

Of interest to us machine vision people though is the gauging technique. This was developed by General Inspection of Michigan and can be seen in an excellent video on their website.

If you watch the movie you’ll hear repeated references to the patented technology. Well patents are a matter of public record, so I did some searching.

This led me to US patent number 5,608,530, which discloses the details of General Inspection’s gauging technique, and I thought, “Well that’s clever.”

I’m not going to waste screen space regurgitating the patent here, so if you want the low-down, use the number that I have so kindly retrieved for you, and take a look yourself. Just remember though, that attempting to profit from this patent without entering into an agreement with General Inspection may open you up to legal action.