if it's not one thing, it's another. Ariel Glenn ariel@columbia.edu ----- http://www.nytimes.com/library/cyber/week/101397patents.html Engineer Invents Computerized Surveillance System By TERESA RIORDAN Imagine that a city park were studded with discreetly placed cameras that fed images into computers programmed to keep a watchful eye. This may sound darkly Orwellian, but David Aviv, a former aerospace engineer, has patented exactly such a system as a way of combating crime. Aviv said his invention, which he calls the Public Eye, used pattern recognition to detect robberies or acts of violence. He said he had digitized and stored a library of physical interactions. "We employed actors to do re-enactments of muggings," he said. "We had 10 different sizes of muggers and 10 different sizes of victims." The camera sends to a computer the real-time images of a person getting money from an automated teller machine, for example. The computer then takes a snapshot and compares the image against the library of threatening interactions. "It takes another snapshot and then another snapshot and does a similar comparison over and over again to reduce false alarms," Aviv said. "I'm describing this in slow motion, but it actually takes place every fraction of a millisecond." If the computer detects a malicious act, an alarm promptly alerts the police or a paid guard. Aviv said he also used a type of pattern recognition, called word gisting, to detect aggressive verbal interactions. Muggers, according to Aviv's research, use a limited vocabulary. "Mostly they say, 'Give me your money,' and then use a lot of cuss words," he said. His word-gisting library contains about 20 basic words, spoken in a number of different dialects. How is Aviv's system different from having a human guard observe a bank of television monitors? "Guards get tired," Aviv said. "And they are expensive." Aviv estimated that it cost about $130,000 a year to have one site manned by guards 24 hours a day. "My system you could lease at $500 a month," he said. "You're not going to eliminate all guards, because you still need someone to run over when a hostile act is taking place." Aviv's company, ARC Inc., which is based in Las Vegas, is seeking financing for further development of the surveillance system. He received patent 5,666,157.