Bokode: Imperceptible Visual Tags for Camera Based Interaction from a Distance
http://web.media.mit.edu/~ankit/bokode/

Could it be the next RFID+AR mashup? I can see it in pointer apps, tag a space etc.

"Current optical tags, such as barcodes, must be read within a short range and the codes occupy valuable physical space on products. We present a new low-cost optical design so that the tags can be shrunk to 3mm visible diameter, and unmodified ordinary cameras several meters away can be set up to decode the identity plus the relative distance and angle. The design exploits the bokeh effect of ordinary cameras lenses, which maps rays exiting from an out of focus scene point into a disk like blur on the camera sensor. This bokeh-code or Bokode is a barcode design with a simple lenslet over the pattern. We show that an off-the-shelf camera can capture Bokode features of 2.5 microns from a distance of over 4 meters." Annotated link http://www.diigo.com/bookmark/http%3A%2F%2Fweb.media.mit.edu%2F%7Eankit%2Fbokode