Computer has eye for suspicious behavior

Bryn Nelson Columnist

That guy meandering back and forth on a downtown street could be seriously lost. Or serious trouble. A computerized surveillance system in the works could help decide which, with its wide-angle panoramic shots, location tracking software and ‘smart’ video cameras that flag suspicious behavior.

Ultimately, the system could chart the normal walking trajectories of pedestrians to spot atypical movement and then seamlessly track people of interest as they travel across a city. The goal is an intuitive control system that allows security or law enforcement personnel to see “what people do, when they do it and where they do it,” said James Davis, an associate professor of computer science and engineering at Ohio State University.

“The best pair of eyes are still on a human,” he said, stressing that his research isn’t meant to procure a computerized replacement. With a new generation of intelligent surveillance systems promising to recognize relevant patterns amid all the clutter, however, human controllers may gain more control than ever before over the constellations of video cameras monitoring public streets and private companies.

At many surveillance centers, Davis said, workers face a bank of TV monitors showing tens or hundreds of video streams. “When they’re looking at one monitor, that means that 99 others are not being observed,” he said. Computers that filter each video stream for atypical content, on the other hand, could alert security personnel to those scenes that merit a closer look.

For the first phase of the project, the researchers expanded the narrow “soda straw” views of many security cameras into wide-angle panoramas. Each computer-guided camera snaps pictures from every angle within its field of view, Davis said, and software merges them into a seamless panoramic image resembling that of a large fish-eye lens.

Courtesy James Davis/Ohio State University A computerized surveillance system in the works could help security officers sort between lost tourists and plotting criminals, with wide-angle panoramic shots like this one, location tracking software and 'smart' video cameras that flag suspicious behavior.

The stitched-together view isn’t quite live, but a controller can click on any spot within it to capture live footage of the specified location or draw a line on the screen to indicate where the camera’s angle should align, like along a crime-prone alleyway.

But one camera can only see so much.

To expand the system’s utility, Davis and his team have designed software that maps the fish-eye panoramas onto an aerial view of an area. Click on a spot on the Google-like map, and any monitors displaying that area will pop up.

Tying the panoramas to map coordinates means every pixel can be assigned a latitude and longitude. Essentially, one worker could recruit multiple cameras to converge upon a street corner or city hall with a simple point and click of the computer mouse.

With each camera’s field of vision linked to geo-referenced coordinates, anyone who walks or drives across a scene also can be tracked. “Say you’re looking at someone through a particular camera, and you click on that person on your video screen,” Davis said. “The camera would latch onto that person and pan and zoom around them as long as it could.”

The task of tracking a suspicious pedestrian could be handed off to successive cameras within the network, while the walking trajectory is captured on the aerial map. “In real time, we could feed back where that person’s coordinates are in the real world, so someone at a remote location could go check it out,” Davis said.

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