Issue #202 | July 30, 2009 | by Andy Kowl

Those alchemists at the Massachusetts Institute of Technology are at it again.

The folks that brought you the new wave of RFID are once again introducing barcode replacement technology. Called Bokode, cameras around the world can already read them; no additional scanner required.

Dr. Ankit Mohan, one of the five scientists at MIT Media Lab who conceived of this invention, sees the ubiquitous nature of cameras as one of the strongest advantages to the new data-laden marks over RFID. In effect, everyone is carrying a reader/scanner already.

If your current cell phone cannot read a Bokode, your next one probably will be able to. This is not because the hardware manufacturers are adding Bokode standards, but because the tags are optical and can be read by optical readers—cameras to you.

Some uses projected for the Bokode are those touted for NFC technology, such as being able to extract information from signage with your cell phone about upcoming events and ticket information. They also suggest future apps may include "crowd gaming, smart whiteboards, and advertising."

Another application might be detailed nutrition information, or even suggested recipes, from scanning a tiny dot on food packaging. Its unobtrusive nature and universal read-ability allows for consumers to take advantage of the tag in new ways.

David L. Chandler reports in MIT News from an interview with another of the Bokode inventors, Assoc. Prof. Ramesh Rakar, "Until now, there have been three approaches to communicating data optically: through ordinary imaging (using two-dimensional space), through temporal variations such as a flashing light or moving image (using the time dimension), or through variations in the wavelength of light (used in fiber-optic systems to provide multiple channels of information simultaneously through a single fiber)."

Focusing on infinity
The key development upon which this technology hinges is using an angular dimension in encoding the image containing the data. According to Chandler, "Rays of light coming from the new tags vary in brightness depending on the angle at which they emerge."

"The Bokeh effect" is a recognized phenomenon on all cameras when they lens is set to a shallow depth of field, which the photographer's eye can't see. It is focused on everything (or nothing) or infinity. If you do focus a camera, the Bokeh is a group of light images, a "cone of rays," coming from an out-of-focus point creates a blur on the camera's sensor.




"You are now entering another dimension . . . of sight. . ."*
Get this: By using this out-of-focus dimension you can actually collect data without the tag being noticed by the human eye because, of course, in the everyday world we see in a dimension which is visually in focus. In fact, a camera focusing on a product containing a Bokode cannot pick it up, because it's out of focus! That is so cool, one step away from Frodo's elven cloak of invisibility. (*Rod Serling would have loved this.)

In other words, this tiny dot, about 3mm in the MIT experiments, on a package would not be much more noticeable to the eye than the trademark symbol on the brand name. I remember in the 80's being horrified when I was forced to add barcodes to the until-then unspoiled front cover of newsstand magazines I was publishing. These less than 0.1 inch marks would not detract from the overall graphics around a magazine cover or packaging or signage like their party-killing cousins, the 10x-larger barcodes, do.

This Bokeh area is hundreds of pixels in diameter, which can contain thousands of bits in a binary pattern of black dots, currently looking like crop circles of data. There is as yet no standard "language" to translate the data Bokodes can provide; but this technology is in its infancy.

Ankit Mohan sees the dot patterns used in their test just as the beginning. "These were printed using current commercial printing methods on films," he said. He pointed out that future, far more complex patterns will add richer content choices for tag users, possibly using holograms.

Line of site reads which offer positioning data
Like barcodes, these optical tags require line of site to be read, so they will never substitute for the most widely recognized advantages RFID offers. Nobody can fault the inventors for making overly-enthusiastic claims, like Bokodes offering greater security than RFID tags. But when pressed, Mohan admitted this is primarily due to the fact his tags can only be read in your camera's field of vision. "But if one were on a credit card," he added, "nobody could scan it inside your pocket." Touché.

Each pattern also provides angle and distance estimates from the pattern of the image, which Mohan sees as another plus for business users who gain positioning information unavailable with barcodes or single-reader RFID. Remember this is based on angles; and that angular information is read by a matrix in the dot pattern.

When asked if the unfocused nature of a Bokode was similar to those hidden-image illustrations, where you have to unfocus your eye to see the optical illusionary effect, Mohan said, "Not quite; the similarity, though, is in both cases you are focusing on infinity."

The other members of the MIT Media Lab team which developed this new visual tagging are Grace Woo, Shinsaku Hiura and Quinn Smithwick.