My previous blog talks about using RFID for navigation. The only problem is that the reader is not cheap and is hard to come by. This blog talks about an alternative for the RFID.
QR code is good because it can tolerate high margin of errors. QR code can be scanned using a hand phone. Thus the data and the reader is available cheaply. QR Code need not be read from a close proximity. Just enlarge it and it can be read from a distance.
I tried a two inch square QR code (1234-56) and it can be read from a meter away. Proportionally, a 5 inch (12.7 CM) should ideally be read from 5 meters away. In actual fact, it can be read at 3 meters distance only . However, that will be good enough otherwise it cannot fit the camera view at close distance.
The use of it is similar to RFID. There is a mapping of all the QR code within the area. They are placed 3 meters apart. 3 meter is used to ensure that the next QR code is within scanning distance. Using the same triangulation method of the RFID, the same navigation method can be done.
Obviously, the QR code should be hanging high enough so that human traffic will not obscure it. Since it is passive, Visual Handicapped may totally lost trace of it and wonders off course. Illumination is also a issue unless the place is perpetually lit.
See my post on RFID here.
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