Draw, you’re on camera

The video surveillance company behind London’s congestion charging scheme has announced trials in which CCTV technology will be used to provide real-time information both on board trains and at stations.

In two to three month’s time COE willl begin conducting a trial at Clapham Junction railway station in south London. Video surveillance cameras coupled with intelligent algorithms will be used to spot people engaged in graffiti activity at the station. While Clapham Junction may be the busiest station in the UK, COE’s chief technical officer, Mark Marriage, said that the problem is one that affects almost every council in the UK.

‘Graffiti is a tremendous problem for UK councils, particularly the expense of cleaning it up,’ he said. ‘Most councils now have budgets for graffiti cleaning, but the problem is that once it’s there it is very hard to get off.’

Marriage added that a particular problem was that once an area had some graffiti then it quickly spiralled out of control and whole walls would become covered within days. The key to stopping it was to nip it at the bud, he said. To do this councils need to know when and where graffiti activity is taking place. They need instant information when a station has been targeted so cleaners can quickly be deployed. This is where COE’s advanced algorithms come into play.

The system works by including these analytical algorithms with COE’s video codec — a device which converts an analogue camera signal into a digital signal and compresses it for transmission over a digital network. As well as this role, COE’s X-Net G3 codec also runs analysis software which can look for movement within the camera’s images.

‘It will analyse when people in a certain area are carrying out a certain kind of motion,’ said Marriage. ‘The aim is to put cameras around Clapham Junction that flag alarms when they spot something suspicious.’



False alarms

He added that most existing simpler motion detection CCTV systems trigger far too many false alarms to be really relied upon.

‘You often don’t know if it’s a person walking through, two people standing chatting or whatever. When false alarm rates are high the operators lose confidence in the system so they don’t take as much notice. This means the value of the system drops over time,’ he said. He claimed that COE’s systems, using more intelligent algorithms, have a far lower false alarm rate.

COE is also trialling video surveillance technology that is able to spot abandoned bags or suspicious behaviour and then pass that information on in real-time, from moving trains, on both underground and overground lines.

‘It is very hard to do, but the algorithms are getting better and better,’ said Marriage. As well as intelligent software, COE has also been trialling the wireless systems that pass on information from the trains, something that Marriage said was a really important part of the firm’s current work.

The company recently successfully trialled high-quality live security video streaming to and from a Capital Corridor train in Silicon valley in California. Using WiMAX radio technology the video was sent from the train while simultaneously sending a level crossing camera video stream back to it.

Until now this kind of system has not been possible because of poor wireless availability on moving trains. It will allow remote control centres to monitor what is happening on board a train in real-time — essential in any disaster or terrorism scenario.

COE has also installed transmission technology on the Singapore underground system, Delhi Metro, Hong Kong rail and the Düsseldorf and Valencia metro systems. On the Singapore North East Line the company developed a live security video system for in-carriage monitoring which is now in service along the 19-station route. The system provides video streams to station-based control centres from every carriage in the train.