CHICAGO -- Renee Singletary has noticed a big change since police mounted a conspicuous video camera near the West Side barbershop where she has worked for a decade.
"It's so much quieter now," said Singletary, 42. "Before, there were kids hanging out doing whatever. It was unsafe to walk around."
The camera is one of 30 installed last summer by Chicago police as high-tech scarecrows to chase off gangs and other street thugs. The remote-controlled cameras, mounted on lampposts high above intersections in rough neighborhoods, can rotate 360 degrees and zoom in tight enough to read a license plate, feeding video directly to squad car laptops.
Fifty 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.
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 legislators 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 at Deal Beauty Supply and General Merchandise, within sight of another camera in the East Garfield Park neighborhood, about 5 miles west of downtown. "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 carry the Chicago Police Department seal.
State Senator Rickey Hendon has sponsored legislation to limit how many devices police install and to get rid of the cameras' attention-getting blue strobe lights. 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. Officers are reminded that using the system for anything beyond viewing public places would violate the Fourth Amendment, police spokesman Pat Camden said.
"We give these guys basic discretion in life-and-death situations, and using these pods is no different," Camden said. "If an officer violates department policy, he would be disciplined."
He declined to say what that discipline could be, calling such a situation hypothetical.
The American Civil Liberties Union in Illinois said it considers the cameras constitutional as long as police use them only to monitor street crime, although a spokesman said privacy questions probably will mount as more cameras are installed.
"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 the number of 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 during big downtown events but not 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 the number of shootings by 50 percent.
Chicago officials say crime has plummeted within a block 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.
Some residents said gang members simply moved their activities to the side streets, a phenomenon specialists call displacement.
Chicago Police Assistant Deputy Superintendent Ron Huberman, who ran Operation Disruption until a recent promotion, acknowledged the effect but said police have beefed up their presence in outlying areas.
"When dealers move out, we can pick them off," Huberman said.