Bar code recognition in apps

I wanted to ask how does Bar code recognition apps works (like Goggles)? Where do they get the bar开发者_开发问答 code information?

There are a variety of standard formats for barcodes. Typically, a barcode app will (somehow) apply some image processing to determine which kind of barcode it's looking at, and then interpret the image accordingly. Figuring out which kind of barcode boils down to making an educated guess based on some set of heuristics.

Once you know which kind of barcode you're working with, it's much easier to process it.

See also: QR Code#Standards.

Google Goggles and Google Shopper use a (modified) version of the ZXing library for barcode scanning. Not surprising as it is all from Google. The barcode data comes from internal sources and from sites on the web.