Moving Images

The events 12 months ago in LONDON certainly underlined the vast improvement in the quality of CCTV evidence available to the police compared to that provided in past incidents. For example in the Jamie Bulger case a decade ago the limitations of the low contrast images collected are frequently referred to as an example of poor CCTV, not withstanding the tremendous assistance that this evidence provided to the police in locating the murderers.

By contrast the images captured on buses, trains and stations in London have been noted by the public and press alike as being of high quality and have proved invaluable to the authorities in apprehending suspects connected with the failed attacks on 21/7. Much of this change can be attributed to the advent of digital recording, improved camera technology and the extensive nature of the CCTV infrastructure we now have in the UK and shows how important it is that our industry continues to innovate.

Catalyst for change

Looking at the reaction to 7/7 both in the UK and Europe, the focus naturally has been to heighten vigilance at railway and bus stations and, on the move, in commuter trains and buses.

With the UK being a mature market, having an estimated 4.5 million CCTV cameras installed, the priority has been on upgrading the existing infrastructure from analogue to digital and ensuring that what is already in place is used to best effect.

For other countries, starting from a much lower base where CCTV is concerned, the events in London have served as a more dramatic catalyst for change. In France for example the Interior Minister announced plans to increase video surveillance in Paris which has 20,000 CCTV cameras compared to 500,000 in London. Measures across Europe are certainly likely to be concentrated on the transport infrastructure, the City of Berlin and the regional government of Brandenburg unveiled plans to add cameras to the existing network covering public transport, while Moscow is to install an extensive network of video cameras in its metro system and has set a target of installing cameras in every carriage.

The value of CCTV images was certainly demonstrated for both 7/7 where those obtained from Luton railway station showed clear, identifiable images of the perpetrators and for the aborted attack on 21/7 the police were able to rapidly issue images of the alleged culprits captured on buses, tube trains and stations. With the potential for images to also end up in court as evidence, it is important that consideration is given to best practice so that this footage can withstand scrutiny. This depends on a number of factors, including image quality and authenticity, storage, the method used to export images from the recording system, playback, operator/owner awareness, and the maintenance of a comprehensive audit trail. For more guidance on this issue please refer to the BSIA's Code of Practice for Digital Recording Systems which can be downloaded from www.bsia.co.uk/download.html.

From air to ground

In terms of the sort of systems that are now being specified across Europe, in the face of the ongoing threat, and also to help tackle more usual problems such as vandalism and assaults on staff, it is mobile digital CCTV recorders that seem to be to the fore. When fitted to trains and buses, for example, these compact, self-contained, systems are capable of continuously monitoring the inside of a carriage or bus. On trains there is even the potential to conduct remote surveillance on key routes, so complementing the existing permanently positioned CCTV infrastructure.

The origins of this technology can be traced back to the aviation sector where, since the mid-1990s, such systems have proven their worth on commercial passenger jets. Here digital recorders, linked to internal and external cameras, have been able to assist aircrew and attendants by providing critical monitoring of the cockpit door, passenger cabin, cargo hold and the undercarriage of aircraft. Now, spurred on by more sophisticated software, ever-increasing computing power and the advent of low cost, high capacity disk drives, the economics and refinement of these mobile multi-camera digital recorders is such that they are proving an attractive proposition for installation on the ground.

As well as the obvious potential of this technology to address the vulnerability of extensive public transport infrastructure in the light of events such as 7/7, by helping operators to spot unusual activity, it can also be adopted to tackle the day-to-day headaches of vandalism and assaults on passengers and staff.

Applied as an overt measure, with the cameras in public view, experience suggests that this provides a significant deterrent to criminal damage, delivering much needed reassurance to the travelling public. This positive benefit was underlined in a trial of our own TransVu system in the Netherlands by NS (Netherlands Railways) on eight Sprinter trains on the Zoetermeer Stadslijn (City Line) which found that 60 per cent of commuter train passengers felt safer with digital recorders and cameras installed, train staff also believed that their working environment had improved and damage due to vandalism plummeted by 45 per cent. During the test period video recordings were reviewed on several occasions, assisting the police and the train operator to solve a number of incidents.

When the trial ended it helped the authorities to apprehend arsonists, who had set fire to a train at Den Haag Central station, from the quality of images collected. Significantly, the success of the trial has lead to its expansion to every double train on the Dutch route, each featuring 14 cameras and 2 recorders.

Recording on the move

The French Interior Minister announced plans to increase video surveillance in Paris, which has 20,000 cameras compared to London’s 500,000...

So what should a typical multi-camera digital recording system be able to offer transport operators? Units ought to be capable of multiplexing and recording from up to eight video cameras per train carriage or bus. Further, multi-channel audio recording can be used to store relevant voice information and the associated images from multiple points in a vehicle, especially useful in incidents of staff or passenger abuse.

Storage is usually via one or two internal hard disk drives, although some operators may prefer a single removable drive which can be taken from a unit in the event of an incident.

Whilst to a user it may appear that this type of unit operates in a similar way to a multiplexer and VCR during standard recording, there are significant benefits beyond these more traditional approaches including, of course, the fact that everything is stored digitally. The latest units can for instance apply different record rates to specific cameras. As a result of this 'variable rate' recording, more important cameras can be prioritized in the recording sequence. Alarm inputs or system events can be used to trigger changes in the recording speed, making it possible to record incidents at a much faster rate than normal.

When making a selection, it is advisable to look out for solutions with an advanced go-to-time feature, supporting playback from a specified time and date to tie-in with particular incidents. It is also beneficial if the system software supplied facilitates visual searches of camera images at up to x1000 normal speed and even closer inspection at one quarter speed (slow motion) to allow for the rapid location and detailed study of incidents.

Power management

Auto power management is certainly becoming a more common feature in multi-camera digital recorders. Typically this stops a unit recording and closes down operation 15 minutes after a vehicle is taken out of service - a time period which can also be defined by the user. The unit will also conduct a controlled and timed power down sequence when the vehicle's voltage has fallen below a set level. Once the minimum operating voltage is reached this is immediate. With a pass through relay controlled power feature, during normal operation, voltage is supplied (the same as the input) to peripheral devices such as cameras. This is removed when the digital recorder itself is powered down.

Rugged construction

Undeniably, the passenger transport environment places rigorous demands on any electronic system so the solution selected for this type of application has to be extremely durable. Ideally the compact sealed recorder unit needs to be suspended via aerospace grade mountings to eliminate heavy vibration.

With wireless Internet access starting to become more commonplace on trains, consideration should be given to systems which, when combined with a broadband spectrum transceiver, have the capability to supply real-time information on a vehicle's operational environment back to a control station.

Where this facility is not available data, including speed, can be logged by for downloading later.

In some cases, to enhance protection for staff and passengers, digital recorders are linked to a panic button. In the event of an emergency, the panic button is simply activated by authorised personnel, such as drivers, so initiating an immediate call to a control station for assistance.

An eye on the future

Looking ahead, there is little doubt that multi-camera digital recorders are going to become an ever more common sight on the public transport network across Europe, not only in the face of new global uncertainties but also to deter and respond to vandalism, including arson and graffiti, and attacks on staff.