Surveillance

CCTV in a safe city

21 May 2009

Mark Medwecki, Superintendent at Hong Kong Police’s Crime Prevention Bureau, shares his views on the territory‘s surveillance landscape.

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Use of CCTV is becoming more and more widespread in many parts of the world. In the UK, believed to be the most “watched” country in the world, it is estimated that there are more than four million CCTV cameras deployed in the country – in fact, no one knows the true figure as the estimate is based on an extrapolation of the number of CCTVs found in a small area in the UK capital. However, there is no doubt that CCTV deployment in the UK is widespread and major criminal and terrorist investigations rely on images from these cameras to identify suspects and secure convictions.

Hong Kong is no exception and CCTV deployment is widespread. There are few commercial premises of any size that do not have CCTV coverage of some kind and likewise, there are relatively few residential premises that do not have CCTVs installed somewhere. Recently, the Housing Authority of Hong Kong, which is responsible for housing about one half of Hong Kong’s total population, embarked on a project to upgrade all the CCTV systems in public housing estates, which provide accommodation for about half of Hong Kong’s population, to digital systems over a period of five years. This project is now well under way and not only will the quality of recorded images be far superior to those produced by the analog systems being replaced, the new system will use far more cameras in each building making coverage more comprehensive. Likewise, many commercial enterprises are now replacing existing analog systems with digital systems which all suggests that there is a convincing case for the effectiveness of CCTV.

But Hong Kong is different in one respect; unlike other jurisdictions such as the UK, Australia and, closer to home, Singapore, there is no surveillance of public places by the authorities for crime prevention purposes. In the UK many city centres now have CCTV surveillance systems monitored 24 hours a day and in the event of an incident the police are alerted and can therefore respond immediately with the result that there is no need for much investigation after the incident. In fact, it has been claimed that experienced operators are able to detect signs of impending trouble and alert police even before there is a full blown incident! Widespread deployment of CCTV systems enhances the feeling of safety in city centres and there is strong public demand for more such coverage. Hong Kong, the public has firmly rejected public surveillance of this type. In the nineties, following the Lan Kwai Fong tragedy on New Year’s Eve 1992 when over twenty people lost their lives, it was proposed that a CCTV system be installed to assist with police crowd management in the area. The proposal led to a public outcry and was shelved. However, recently there has been an initiative to install a surveillance system in Mong Kok following an incident where acid was thrown from a building onto passing members of the public. It looks as though this system will get the go ahead and Hong Kong willow other jurisdictions in this area.

As elsewhere, CCTV systems in Hong Kong are often marketed as prevention measures but the reality is that they are most useful as aids to criminal investigation. This has been the case in other jurisdictions as well. The investigation following the London terrorist bombing in 2005 was heavily reliant on video footage obtained from surveillance systems dotted around the capital and for many proved the usefulness of CCTV. But, at the same time, the bombings drew attention to the fact that being able to identify who was responsible for the bombings doesn’t help prevent such incidents. In addition, investigations such as that of the London bombings require a huge amount of police resources to view the video footage. These two issues as well as future directions of CCTV systems, were addressed at the Future CCTV 2008 Conference held at Raffles Hotel in Singapore in April this year and attended by the author.

One of the speakers, Graeme Gerrard, Deputy Chief Constable of the Cheshire Constabulary in the UK spoke about the desire for prevention and not just detection. He pointed out that even minor cases can require the review of hundreds of hours of video footage which is a huge drain on police resources. In the long run, this is not a sustainable approach and the emphasis must move to prevention rather than detection.

The issue of using CCTV to prevent rather than to detect was taken up by one of the key presenters at the conference, Professor Brian Lovell of the University of Queensland, who is involved in research into “smart” technologies. Such research has been driven mainly by the threat of terrorism and Professor Lovell pointed out that one of the main reasons for more extensive use of CCTV systems in many countries was the threat of terrorism, but if all that CCTV can do is help with post incident investigation, then this is not of much use. Governments worldwide want to prevent terrorist acts and not just be able to investigate them after they happen.

The quality of CCTV images has improved with the switch to digital recording, but the key to further progress is to make CCTV smarter so that it can help prevent incidents rather than just leave a visual record of what happened. There are now technologies available that can be used in conjunction with CCTV systems to leverage their usefulness in existing applications and in a number of new applications. The first of these involves the replacement a number of split screen monitors in control rooms to watch over a facility.

Systems now exist which use 3D modeling (similar to that used in video games) which enable integration of several – hundreds or more – CCTV cameras that provides a total view of a facility one a single monitor. An operator in a control room can then view any part of the facility by using a game controller like device to “move around” a facility. The computerised 3D model provides a framework while the cameras superimpose “reality” onto the model. So, at an airport, for example, it is possible to look at the monitor and, using the controller, view any part of the airport. Where an area is not covered by a camera, this will show on the monitor as a computerised graphic.

The advantages of such a system are that it gives an operator total orientation of the facility very quickly and provides the ability to follow any incident across the field of vision of several cameras intuitively, that is to say without having to remember which camera covers which area. All the operator needs to do is follow the action with the controller device and the switching between cameras will be automatic.

Another advantage of such a system, is that in the event of an incident, the images can be viewed anywhere as transmission is via broadband networks. This means that managers in remote locations can very easily take control of incidents. On top of such a system, video analytic technology could be used to detect suspicious behaviours. Most readers will be familiar with such applications, a common one being the detection of objects being left unattended in such places as railway platforms. The MTR Corporation has been looking at such systems for deployment in Hong Kong train stations. But as Professor Lovell pointed out during the conference, such systems could cover a multitude of situations. Software could detect “shop lifting” before it happens as research has shown that in virtually all cases persons about to steal in shops behave in a particular way which can be detected by video analytic software.

With the increasing threat of terrorism, facial recognition technology has offered the hope of a solution to problems of recognising suspects and detecting false identification documents. This technology has now developed to the extent where it works in situations such as passport control desks or access control systems in buildings. But what if it were possible to pick faces out of a crowd so to speak? Developments are going ahead in this area where the main problem is that facial recognition relies on high resolution images but transmitting the necessary amount of detail through a CCTV system would overload the system.

The approach under development in this area is to come up with a system that is able to pick out faces in a crowd and transmit those images in hi-resolution mode while transmitting the remainder of the image (over 75%) in low resolution mode. Lastly, this type of technology can be used to recognise vehicles but not only with a view to identifying vehicles used in criminal or terrorist contexts but also to help control traffic. For example, traffic flow could be controlled to allow priority for public transport or emergency vehicles.

These developments all point to greater automation and less need for human monitoring and will help prevent crime and terrorism in areas with public access such as transport centres, identify and track persons and/or vehicles of interest, detect persons performing dangerous acts before the act occurs.

Hong Kong stands out as having a low perceived terrorist threat and a low crime rate but this not mean that security doesn’t have to be of a high standard. In fact, Hong Kong has come a long way in its deployment of security systems and while the majority may be low tech, the reality is that they help keep our city safe. There is public antipathy to the notion of CCTV in public places and it is unlikely that this will change. However, large sums are spent both by the government and the private sector on security systems. It is important therefore that such systems are set up in a way to ensure maximum benefit for minimum long term cost.

Merely using CCTV systems as passive recording devices to be reviewed postincident no longer represents the best use of this technology.