Bokode: Imperceptible Visual Tags for
Camera Based Interaction from a Distance
ACM Transactions on Graphics (Proceedings of SIGGRAPH 2009)
AbstractWe show a new camera based interaction solution where an ordinary camera can detect small optical tags from a relatively large distance. 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. We use intelligent binary coding to estimate the relative distance and angle to the camera, and show potential for applications in augmented reality and motion capture. We analyze the constraints and performance of the optical system, and discuss several plausible application scenarios.
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Application ScenariosBokodes open up a whole new range of applications in the areas of tagging, user interaction, machine vision and near field communication not possible with traditional barcodes. Here are mockup sketches of just some possible application scenarios for Bokodes. Please see the paper for more details.
|Street Mapping Services such as Google Streetview: Shops use Bokodes to provide meta information to the trucks as they drive down the street taking pictures.||Rear projected Microsoft Surface: Tiny Bokodes attached under physical objects placed on the table surface are used to decode position, identiﬁcation, and the angle the object (such as a stylus pen) makes with the surface.|
|Multi-user interaction with a large display in a classroom or conference: The participants use Bokodes with unique identifiers to interact with displays from a distance.||Crowd Gaming in Public Spaces: Participangs use Bokodes to control their characters on a shared display from a distance.|