One of the most effective crime fighters these days never sleeps, can compare huge numbers of images in an instant and has a photographic memory. And thousands of them have been deployed to train stations across the nation.
Security cameras have played a key role in tracking individuals suspected of committing crimes. Yet further upgrades to the cameras will enable them to better identify individuals in blurry images and even detect specific patterns of behavior.
Although police are salivating at the opportunity for higher performance cameras and wider security networks, some are raising concerns about the idea of constantly being watched and recorded by strangers.
"Our society now is becoming more group-oriented, and (these security networks) could be put to arbitrary use to exclude people with opinions different from those of the majority,” said Tatsuya Mori, a filmmaker and writer who directed a documentary tracing the lives of Aum Shinrikyo followers. “We haven't had enough discussion on what we gain and lose from such surveillance."
After a man was stabbed at Shibuya Station in Tokyo, dozens of Metropolitan Police Department investigators went to major train and subway stations in suburban Tokyo and collected security camera footage. They stayed up all night looking for someone matching the suspect's description and determined his route.
Two days later, a 32-year-old part-time worker living in Asaka, Saitama Prefecture, was arrested on May 23 of suspicion of attempted murder.
Hitachi Kokusai Electric Inc., a subsidiary of Hitachi Ltd. in Tokyo, is developing a system that it says will improve the current setup.
Its technology analyzes faces picked up by a security camera, compares them to other images stored on a server and finds those that match.
The company says that even with an unclear image, the system can differentiate between ear and nose positions as well as facial contours to instantly narrow tens of thousands of images taken at other places and times down to a dozen or so.
It can also search for data on up to 36 million people in one second. By setting up an elaborate network of cameras and connecting it to the server, the system can show what a person was doing, as well as when and where, the company said.
Although faces recorded from the side or in the dark can hinder accuracy, Hitachi Kokusai Electric says it is in the final stages before commercial viability.
"We need more accuracy for criminal investigations," said Naoyuki Shimbo, the deputy chief engineer at the company's Video and Communication Systems Division.
Director Yasushi Yagi of the Institute of Scientific and Industrial Research, Osaka University, an expert on visual information processing, is now researching a system to distinguish between individuals by the way they walk.
He says that people walk in distinctive ways that we are not aware of, and his system will be able to recognize walking styles based on posture, hand movements, strides and other features, even at a distance of 100 meters.
He hopes to make a practical version within five years, but investigative authorities are already seeking his expertise.
"The day is not far off when we'll be able to take a single camera image and use a network to instantly figure out what the person was doing before and after," Yagi said.
According to the transport ministry, about 56,000 security cameras were operating in train stations nationwide as of March 2011, nearly triple the 20,000 or so in March 2004.
After the sarin gas attack on Tokyo subways in 1995, Tokyo Metro Co. installed security cameras in all 170 stations it operates. In fiscal 2010, it began installing new high-resolution cameras.
Tokyo Metro says it can store video for long periods and check footage at its operations center and company headquarters.
In the first year, the subway operator had a network of 6,542 cameras in place. But since then, for "security reasons," Tokyo Metro has not revealed the number of cameras or how they are used.
Seibu Railway Co. and Tobu Railway Co. also do not publicize how many cameras they operate or how long video is stored.
East Japan Railway Co. has around 12,000 cameras installed in its 1,689 stations and stores video for about a week.
There are 810 cameras installed in the 101 stations of the Tokyo metropolitan government’s Bureau of Transportation, which operates the Toei subway lines. The bureau says it stores video for seven days.
(This article was written by Koji Kitabayashi and Hiroko Saito)
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