"But wait a minute," some of you may say. "I have downloaded and used a barcode for my airline ticket on my phone and used it to check in at the airport. That seemed to work OK . . . at least sometimes." That is true enough, but the 2D optical imager that reads your barcode is a completely different technology than the red laser scanners in use in the vast majority of retail stores and other locations today.
There are several different types of barcode scanners in use today. The majority of retail stores use laser scanners - either handheld or omni-directional (embedded in the checkout lane) or both. When laser scanners try to read a barcode image on a phone, they are foiled by the refraction effect of the glass, backlit displays, and polarizing filters on the phone. As a result, handheld laser scanners do a very poor job (hit or miss at best) and the ubiquitous omni-directional (embedded) scanners found in most point-of-sale checkout lanes are even worse at reading barcodes on phones. So in most retail environments, linear barcode mobile coupons on smartphones are virtually useless today . . . they practically never work.
