Closed Circuit TV (CCTV) has for years relied completely on developments in the broadcast TV industry for new products. However, in that business, new cameras typically cost in the region of £30,000 each or so and monitors £1000 each or more. CCTV as the poor cousin has therefore had to wait for significant cost reductions to be implemented before being able to take advantage of new techniques. Not any more though. It is increasingly going digital and becoming more closely associated with PC technology, offering both hardware and, increasingly, powerful software facilities at low cost. So what is the likely impact of these developments on the CCTV market and, not to put too fine a point on it, where are the ICT opportunities?

Out with the old

Traditional CCTV systems are mostly based on analogue video technology and usually used for some form of security – for a building or town centre for example – or for traffic surveillance. In this sort of system, cameras are connected to centralized switches and the pictures are displayed on screens and recorded on video recorders using a process where the system switches between cameras on a field or frame basis. Reduced size pictures from all the system’s cameras can be displayed next to one another on the screen but, because of the switching, the picture frequency for displaying and recording the pictures depends on the number of cameras connected. For a typical system with 16 cameras, one picture per second per camera is the result.

This kind of system has other disadvantages too. Because signals have to be transmitted to a central point, cabling is purpose built and often expensive. Transmission over long distances is also technically challenging – if not impossible in many situations. Should the system need to be expanded at a later date, this too is not straightforward. If the switch is fully loaded then a second switch is required, or a larger one to replace the first. If the switch fails, the whole video surveillance operation goes down. This type of system is also a heavy user of videotape – the vast majority of it recording nothing of interest whatever yet the only way to find a particular sequence is to play it all through. Further, it is extremely difficult to do anything with the pictures stored other than just view them.

Going digital solves a lot of these problems. Cameras can be connected through LANs and WANs in IP networks in the same way as PCs. Images can be stored on servers located anywhere in the network. The pictures too can be viewed anywhere on the planet, and in several different locations at once, all in real time if need be. More than that, though, the images can be processed – either at the camera end or in the network – to provide a whole new range of applications and search facilities. 

More than just security

When we think of CCTV, we tend to think of security. However, it already plays an equally important role in the areas of monitoring and control and each of these are set to gain from going digital.

Image processing lies at the heart of the Congestion Charge, which to the mixed views of Londoners is to be introduced from mid-February. This defines a charging zone in Central London where vehicles entering during daytime weekdays will be charged £5 for the privilege. It is being enforced using 230 CCTV camera positions throughout the zone which will provide high quality video-stream signals over a high speed digital network to an Automatic Number Plate Recognition (ANPR) computer system. The cameras will also use Sony X-wave technology to see better in poor light conditions. The captured images will then be sent back to the ANPR system where the number can be read and matched against a database of those who have registered to pay.

Although the system has cost a reported £200m to build, Transport for London reckons it will pay for itself within 18 months. If it works, that must rank as one of the fastest paybacks for a public project. 

Image processing can also be used for quality control in a factory setting. One company, for example, uses it to check the quality of baked food products. Cameras view newly-baked products as they emerge from the ovens. The images are then compared with reference images on a database (the perfect pie, cake, biscuit . . .) and only those that look good are passed. Another variation (biometric software) makes it possible to recognize people’s faces, perhaps in a crowd or at access control points. Increasingly relevant for combating terrorism for example.

Then there’s motion detection. Video traditionally uses up an awful lot of tape. By defining areas of the camera’s screen where motion being detected causes image recording to commence, new surveillance uses become more practical. Combating graffiti artists, for example, or detecting when a particular object is moved.

Machine talks to machine

These techniques may be carried out within the network or increasingly at the camera end, raising the option of reducing the bandwidth required in the network and making it more suitable for transmission over GSM and, later, 3G mobile networks.

A big winner using this approach could be home, and indeed office, security. The prospect of installing standardized equipment without the need for wires has obvious attractions and presents substantial cost reduction opportunities. Home security alarms have become so notorious for raising false alarms that police in the UK at least now require a secondary means of confirmation before they will respond. Video is an obvious secondary means but, using image processing techniques, could well become a new primary method.

Indeed, recent trials of mobile digital CCTV have demonstrated its worth. In one case, houses on an estate in Coventry plagued by petty burglaries were fitted out with miniature, mobile CCTVs. A small number of persistent thieves were identified and charged and break-ins have consequently plummeted.

An interesting consequence of introducing these techniques is also that it serves to create a new machine to machine environment where video systems automatically record, date stamp and catalogue events for subsequent retrieval across open networks and raise alarms as required. The need for constant human supervision with operators sitting in front of banks of TV screens where, more often than not, nothing is happening could become a thing of the past.

Snooper’s Charter?

It does raise concerns, though, about the possibilities of snooping. The UK is the most heavily CCTV-ed country in the EU with the majority of larger town centres and shopping malls now covered by an estimated 2 million cameras in use. Yet even here this has no more than scratched the surface of the potential market for low cost systems with sufficient picture resolution to stand legal scrutiny.

The UK’s Data Protection Act excludes from the provisions of the Act the use of cameras by individuals to protect their own property. No burglar’s rights there then. It is perhaps debatable whether having a notice in your home warning intruders of video surveillance by hidden cameras would have the desired effect in any case.

In public spaces, though, such notices are mandatory. Cameras in public places must also be positioned in such a way that they only cover the areas intended. No peeping into private gardens or through windows into private properties is allowed without permission (which one suspects would not be readily given). There are many other provisions too.

From the point of view of legal evidence, there is also an issue regarding image processing. No processing is allowed on pictures that will be used as evidence, and these must be stored unchanged, suitably date stamped, either at the camera or in the network. Clearly these issues are going to get more complex as image processing features become more sophisticated, costs continue to decline and systems become ever more portable.

 © e-principles 2003

Robin Duke-Woolley

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