Students turn out robot that takes party shots

ST. LOUIS -- Here's a new one for Miss Manners: Is it proper etiquette to take your robot to a wedding reception? What if the bride insists?

For the next wedding Bill Smart attends, he'll bring along Lewis, a 300-pound robotic photographer that wanders around parties, detects faces and takes candid shots.

Lewis stands about 4 1/2 feet tall and looks like a red garbage can on wheels. Inside, two computers no more powerful than a desktop run on four car batteries, getting from five to six hours of power each.

Lewis made its debut at a recent New Horizons in Science Briefing, an annual event for scientists.

Photography wasn't the end goal, said Smart, an assistant professor in computer science at Washington University. But it happened to be a way to combine undergraduate student projects in navigation, interaction and looking at face composition through cameras.

"With a lot of robot stuff, it's difficult to get people enthusiastic," he said. "We're using photography as a framework. You can't show one piece of these applications on their own."

A year ago, Smart's wife, Cindy Grimm, also an assistant professor at Washington University, suggested a photographing robot as a tangible application.

The red frame was custom built by a robotics company, which Smart said has built between 100 and 150 of this particular model. But none that he knows of takes pictures.

Students wrote the programs.

Smart estimates the project cost between $50,000 and $70,000, all from funding for his lab.

Except for the occasional sonar ping, Lewis makes little noise and blends into parties. The robot is programmed to avoid hitting people, although a handler is always nearby to hit one of two manual shut-off buttons, as mandated by law.

Smart said Lewis makes the perfect candid photographer because guests relax and ignore him.

"We're very conscious of being watched. Lewis can't stare at you. Lewis doesn't have eyes," said David Laidlaw, a computer science professor at Brown University who met Lewis at a conference in July.

Guests can see and print Lewis' work on nearby computers linked to the robot through wireless Internet.

Lewis sees through two camera lenses and decides when to use the giant flash. Hardware inside is, in Smart's terms, shaken constantly, so drives are affixed with tape and rubber.

The robot moves along flat surfaces and scans for faces. The camera takes a single frame as lasers and sonar determine how far away the object is. Programs look at the composition of the shot and shape to determine if anything could be skin and a face. If the photographed object matches with how far away the laser says the object is, the picture is sent through the network.

Lewis does all of this between 10 and 20 times a second, slowing down sometimes to zoom in or pan out to minimize empty space.

Laidlaw, himself a photographer, said he generally found picture quality below average.

"None of them were spectacular, none of them were perfectly framed, some of them had the heads cut off," Laidlaw said.

Although he pointed out that Lewis' skills shouldn't be judged too harshly because even the best photographers don't show everything they take, which Lewis does.

Professional photographers have written Laidlaw's lab saying Lewis would never be as good as they are. Smart acknowledged Lewis' pictures could best be described as party shots, similar to ones taken by guests with disposable cameras.

"If you had this as the only photographer at your wedding, you'd be mad," Smart said.

On the Net:

www.cs.wustl.edu/~lewis