CHICAGO (AP) -- In the gang-ridden area where she works as a hairdresser, Renee Singletary has noticed a big change since police mounted a conspicuous video camera at a nearby intersection last summer.

"It's so much quieter now," said Singletary, 42, who has worked for 10 years at Gollies Barber Shop in the East Garfield Park neighborhood, about five miles west of downtown. "Before, there were kids hanging out doing whatever. It was unsafe to walk around."

The camera is one of 30 that Chicago police installed last summer as high-tech scarecrows to chase off gangs and street thugs. The remote-controlled cameras -- mounted on lamp posts high above intersections in rough neighborhoods -- can rotate 360 degrees and zoom tight enough to read a license plate, feeding video directly to squad-car laptops.

A batch of 50 upgraded cameras to be installed later this year will have sensors to detect bullets whizzing through the air, relaying the precise location of gunfire to dispatchers to alert nearby squad cars.

But as Chicago police expand their $3.5 million "Operation Disruption" -- one of the nation's most aggressive uses of surveillance cameras to curb violent crime -- residents and lawmakers are divided over whether the cameras are effective or an invasion of privacy that brands their neighborhoods as ghettos.

"It seems prejudiced to me," said Abdul Bucky, 40, who works within sight of a camera at Deal Beauty Supply and General Merchandise in East Garfield Park. "Why didn't they put them in all the neighborhoods?"

The cameras, which can film day or night, are protected in white bulletproof cases about the size of a small file cabinet and emblazoned with the Chicago Police Department seal.

State Sen. Rickey Hendon has sponsored legislation to limit the number of devices police install and to get rid of the small, constantly twinkling blue strobe lights on each camera. Hendon said the lights have led people to label the neighborhoods "blue light districts."

"I think they're a violation of people's civil liberties," said Hendon, who said he has received complaints from residents who fear the cameras can zoom into their windows. "People going about their everyday lives shouldn't be spied on by Big Brother."

City officials said the cameras are not used to peer into private homes and that they intend to protect people's privacy.

A spokesman for the American Civil Liberties Union in Illinois said the group considers the cameras constitutional as long as police use them solely to monitor street crime, although privacy questions likely will mount as more cameras go up.

"There really should be a societal public-policy debate, with an eye toward ensuring there are specific regulations in place that protect against an invasion of privacy," ACLU spokesman Ed Yohnka said.

Chicago, which led the nation in murders last year, is far more aggressive in using police cameras than many other major cities.

The New York Police Department for years has used cameras in housing projects but has not used any to target street crime. Detroit, Houston and Washington, D.C., have placed cameras in downtown areas during big events but have not used them in high-crime neighborhoods.

Los Angeles has been limited to a closed-circuit TV system installed last year in a large, gang-ridden park, which police said helped reduce shootings by 50 percent.

Chicago officials say crime has plummeted within a one-block radius of each camera. Narcotics calls dropped 76 percent over the first seven months, police said. Minor crimes such as property damage were down 46 percent.

But some residents said gang members simply moved their business to the side streets -- a phenomenon experts call "displacement."

"The displacement effects are real," said Dennis Rosenbaum, a criminology professor at University of Illinois at Chicago who has studied anti-violence programs in 10 cities for the National Institute of Justice. "But if the opportunities for crime aren't as easy to come by, you can successfully prevent crime in a certain area."

Chicago Police Assistant Deputy Superintendent Ron Huberman, who ran Operation Disruption until a recent promotion, said the cameras have resulted in a wholesale reduction in crime by moving drug dealers off their favorite street corners and into outlying areas, where police have beefed up their presence.

"We put officers in surrounding areas, so when dealers move out we can pick them off," Huberman said.

Chicago Alderman Ed Smith, whose ward includes several of the devices, said he has only heard one complaint about the cameras: There aren't enough of them.

"You can call the area whatever you want; just don't call us late for those cameras," Smith said. "I need more."

Chuck Benain, 54, who owns Ryerson Pharmacy on the city's West Side, said he can't wait for more to go up.

"I wouldn't be opposed to having one right there," said Benain, pointing to the intersection outside his storefront. "People aren't afraid to send their kid down the block to pick something up now."