A Wave of the Hand

By Anna Lynn Spitzer

Majumder (foreground) uses multiple projectors, each containing a 
camera and a computer, and a distributed architecture in her
interactive displays. (Photo: Paul Kennedy.)

Irvine, CA, May 4th, 2012 - - Co-workers don’t have to be hundreds of miles apart to benefit from interactive collaborative tools. Sometimes, colleagues in the same room need to contribute input on a project simultaneously. 

Computer science associate professor Aditi Majumder is developing technology to support those co-located collaborative user interactions. Using either gestures or laser pointers, multiple users can move items around on a display, enlarge them, zoom in, open personal windows and create diagrams with multiple colors, working together and simultaneously at interactive speed. 

While interactive displays themselves are not groundbreaking, Majumder’s system is different because it uses a series of plug-and-play projectors, each containing a camera and computer; and a distributed architecture, which runs the same algorithm on every projector. This distributed approach is more efficient, accurate and responsive than systems that rely on a central processor because each projector handles only a small part of the data.

The algorithms on each projector can be easily downloaded, similar to an iPhone app, and the displays scale easily to allow any number of projectors. Regardless of display size, multiple users can interact with it simultaneously, with minimal latency.

The distributed architecture operates in much the same way as a social network, says Majumder. Instead of relying on one central source of information, each projector operates independently, yet shares necessary information with its neighbors.

“When a user opens a window, it may span four projectors so each has to communicate with the others to interpret the user’s intentions and react to it appropriately,” she says. “It’s how [co-located] people interact – they’re very local, yet together they achieve something very global.” 

Now Majumder is working to bring the distributed computing concept to pico projector-embedded cell phones. Picos are tiny projectors that are expected to become as common in mobile phones as cameras; they can create full-sized displays for viewing videos, photos and presentations, and displaying files. Because they’re so small, however, they are less powerful, projecting only 10-30 lumens of brightness (compared to 3,500 lumens in a full-size projector) with a resolution of .25 megapixels (full-size projectors have a resolution of 2 megapixels). 

But using the distributed architecture, the picos will be able to communicate with each other and combine to produce brighter, sharper displays. If two phones (or three, four or more) come close enough to each other, their displays will either overlap, providing brighter viewing, or tile, which increases the resolution.

She is also using the technology to move files from one phone to another with just a gesture, via a Bluetooth mobile network.
Soon, business associates will be able to view PowerPoint presentations on the fly or transfer files without using a USB connection. “As soon as their phones get close to each other they will detect each other,” Majumder says. “It’s a very easy interface.”