SAN FRANCISCO — San Francisco’s surveillance cameras in high-crime areas do not prevent violent crime, according to a new study by researchers at the University of California. The long-awaited study by the UC Center for Information Technology Research in the Interest of Society found the program is hurt by lack of training and oversight, a failure to integrate footage with other police efforts, poor quality cameras, and what may be a fundamental weakness of cameras as anti-crime devices. Mayor Newsom began the program four years ago, but out of concern for people’s privacy, police are not allowed to monitor cameras in real time. Investigators must wait until a crime is reported before looking at footage. Researchers reviewed only the cameras obtained by Newsom. It did not examine those used by the San Francisco Housing Authority in public housing developments. Though they did find no real effect on violent crime, researchers say they appear to have an impact on petty crime. Property crimes were down 24 percent in areas with cameras.