Earlier quoted context omitted.
I think they're great too, but they don't hold more info (per unit area) than other types of symbology like, for example, datamatrix. If you really want to stuff tons of data in the symbol itself, you need PDF417. That can be scanned by a specialized line scanner (admittedly not convenient for phone cameras) QR codes often encode URL's/URI's and the application typically hits up a database upon scanning them just lik…
It is not clear whether these statements are true. * QR codes mandate a minimum of 15% area used for error correction and a maximum of 60%. * Data Matrix codes mandate a minimum of 0% area used for error correction and a maximum of 50%. * The amount of overhead in QR codes (finders, timing, alignment) is probably in the same ballpark as Data Matrix codes (black lines, checkered lines). * PDF417 codes demand low verti…
That said dense 2D barcodes read by dedicated imagers in controlled lighting scenarios, as far as I've seen, are always datamatrix. Not sure if that's merely historical or if there's a technical reason for that.