In a city where surveillance cameras are being sparingly used, the 17 cameras installed along the Bus Rapid Transit (BRT) corridor in South Delhi by the Delhi Multi-modal Integrated Transport System (DIMTS), primarily for traffic monitoring purposes, have regularly come to the rescue of policemen scouring for evidence in crimes where suspects have strayed on to these roads.

The cameras presently installed are basic-purpose pan-and-zoom ones that watch the traffic condition on the BRT corridor to suitably trigger the intelligent signalling system. They also help address traffic problems like spotting accidents and broke-down vehicles blocking traffic.

But DIMTS is in talks with a number of agencies to install high-end automatic number plate recognition (ANPR) cameras along the BRT corridor. These are high-resolution cameras that store video footage, perform optical character recognition to store the licence plate number in digital text format, and in some cases also separately stores photographs of the driver.

The ANPR cameras can either do real-time conversion of licence plate images to alphanumeric characters or they can send them to the server where this image-to-text conversion is done. The vehicle number so extracted is tallied with the database of vehicle owners to extract the details of the vehicle and the owner. High-resolution photographs of the vehicle, driver, and the street-level can also be extracted.

A pilot project using ANPR cameras installed by DIMTS near the airport about four months ago won the instant appreciation of the Traffic Department and was especially helpful in spotting and challaning of those over-speeding. The DIMTS hope to begin installation of the ANPR cameras by early 2013.

ANPR cameras are used in western countries to detect and penalise over-speeding and traffic rules violations. A photograph of the driver, number plate and vehicle shot by ANPR cameras are attached to traffic tickets that are mailed to traffic violators.

A DIMTS spokesperson said the video footage from the present camera system too is regularly sought by the South Delhi police to solve a number of crimes. While recordings are normally stored for seven days, on days when incidents occur the footage is stored for at least a year.

The Operational Control Centre at DIMTS was also in the news last year when after the Delhi High Court blast it began analysing footage from cameras installed at nearby Mathura Road for clues on those who planted the bomb. The footage was handed over to the National Investigation Agency.

On normal days the control centre staff watches the video feed for motorists other than buses which enter the bus lanes, captures images of such vehicles from the video feed, and pass them on the Transport Department which takes it up with the Delhi Traffic Police for prosecution of offenders.

More In: Delhi