Date: 11/4/07
Author:  Stephen Manning
Source: Sydney Morning Herald - Live Wire

Cameras are learning to interpret your moves, writes Stephen Manning.

THE next time you walk past a shop window, take a glance at your reflection. How much do you swing your arms? Is the weight of your bag causing you to hunch over? Do you still have a bit of that 1970s disco strut left? Look around - you might not be the only one watching.

Researchers and security companies are developing surveillance cameras that not only watch the world but also interpret what they see. The latest breed, known as "intelligent video", could transform cameras from passive observers to eyes with brains able to detect suspicious behaviour and potentially prevent crime before it occurs.

Soon, some cameras may be able to find unattended bags at airports, guess your height or analyse the way you walk to see if you are hiding something.

Surveillance cameras are common in many cities, monitoring tough street corners to deter crime, watching over sensitive government buildings and catching speeders. Cameras are on public buses and in train stations, building lobbies, schools and stores. Most feed video to central control rooms where they are monitored by security staff.

The innovation could mean fewer people would be needed to watch what they record, and make it easier to install more cameras in public places and private homes.

"Law enforcement people in this country are realising they can use video surveillance to be in a lot of places at one time," says Roy Bordes, who runs a Florida-based security consulting company. He is also a vice-president with ASIS International, a Washington-based organisation for security officials.

The advancements have already been put to work. For example, cameras in Chicago and Washington can detect gunshots and alert police while Baltimore installed cameras that can play a recorded message and snap pictures of graffiti sprayers or illegal rubbish dumpers.

In the commercial market, Mr Bordes says the gaming industry uses camera systems that can detect facial features. And casinos use their vast banks of security cameras to hunt known cheating gamblers.

In London, one of the largest users of surveillance, cameras provided key photos of the men who bombed the underground system in July 2005 and four more who failed in a second attempt just days later. But the cameras were only able to help with the investigation, not prevent the attacks.

Companies that make the latest cameras say the systems, if used broadly, could make video surveillance much more powerful at airports, ports, homes and at border crossings.

Intelligent surveillance uses algorithms to interpret what a camera records. The system can be programmed to look for particular things, such as people walking where they don't belong.

"If you think of the camera as your eye, we are using computer programs as your brain," says Patty Gillespie, branch chief for image processing at the US Army Research Laboratory in Maryland. Today, the US military funds much of the smart-surveillance research.

At the University of Maryland, engineering professor Rama Chellappa and a team of graduate students have worked on systems that can identify a person's unique gait or analyse the way someone walks to determine if they are a threat.

A camera trained to look for people on a watch list, for example, could combine their unique walk with facial-recognition and height-estimation tools to make an identification. A person carrying a heavy load under a jacket would walk differently than someone unencumbered, which could help identify a person hiding a weapon.

With two cameras and a laptop computer set up in a conference room, Professor Chellappa and a team of graduate students recently demonstrated how intelligent surveillance works.

A student walked into the middle of the room, dropped a laptop case, then walked away. On the computer screen, a green frame popped up around him as he moved into view, then a second focused on the case when it was dropped. After a few seconds, the frame around the case went red, signalling an alert.

IN ANOTHER video, a car pulled into a parking lot and the driver got out. A computer-generated frame was drawn up around him and tracked him as he went from car to car, looking in the windows instead of heading into the building.

In both cases, the camera knew what was normal - the layout of the room with the suspicious bag and the location of the office door and parking spots in the parking lot. Alerts were triggered when the unknown bag was added to the scenario and when the driver didn't go directly into the building after parking his car.

Similar technology is in use by US Marines in Iraq and in the subway system in Barcelona, according to ObjectVideo, aVirginia firm that makes surveillance software.

Still, industry officials say the technology needs to improve before it can be widely used. There are liability issues, such as if someone is wrongly tagged as a threat at an airport and misses a flight, Mr Bordes says.

Mr Troha also warns that humans are still essential to intelligent video to tell, for example, if a person in a restricted area is a danger or just lost. And the cameras can only see so much - they can't stop some threats, such as a bomber with explosives in a backpack. And they can't see what you are wearing under your jacket - yet.

"That is an eventual goal, but we're not there yet," Professor Chellappa says.

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