Reading Bar Codes

I suppose a “bar code” might be something like, “One finger in the air for a Bud Lite, two fingers for a Sam Adams, knock once on the counter for a Jack Daniels,” but in this case I’m referring to those zebra stripe motifs printed on just about everything we buy.

Bar code reading is one of the biggest application areas for machine vision, especially since the introduction of the 2D “datamatrix” codes. Unlike the zebra codes, “datamatrix” codes can’t be read by a laser scanner; instead, a camera system, (sometimes described as a “CCD scanner,”) is needed to do the decode.

Over on the Cognex/DVT Smartlist discussion board a poster recently asked where he could get information on barcodes. I know Cognex have info on their web site, (look under “ID Standards and Specifications,”) but someone else suggested the “Worth Data® Bar Code Primer.” I wasn’t familiar with the company, so of course I took a look. Turns out it’s a really good introduction to bar codes, with a lot of links for further reading, so if your boss has just placed you in charge of a part identification program, you might want to start there.