Tactile Graphics with a Voice is a joint project with the University of Washington and the DIAGRAM center (http://diagramcenter.org/57-tactile-graphics-with-a-voice.html). When VoiceOver is turned on, it gives feedback to users so that they can center and scan QR codes. It is part of a larger project to allow people who are blind to access text on tactile graphics using embedded QR codes.
This material is based upon work supported by the National Science Foundation Grant No. IIS-1116051. This work was supported by the U.S. Department of Education, Office of Special Education Programs (Cooperative Agreement #H327B100001).
The barcode scanning code we used was adapted from ZXing's open source library (https://github.com/zxing/zxing).