CCTV operations in most CCTV operations around the world typically have a high camera–monitor–operator ratio. I am often asked questions on how operators can view so many cameras. The simple answer is that they cannot – it is physically impossible to look at so many cameras. Even if these multiple views were squeezed onto large monitors, they would probably be unusable for detection requirements. There are very few sites where operators have a manageable number of monitors in front of them which also represent the total number of cameras. On the positive side, such a high ratio definitely does lead to success. The Metro Police operations in Cape Town being an example of this.
CCTV operations in most CCTV operations around the world typically have a high camera–monitor–operator ratio. I am often asked questions on how operators can view so many cameras. The simple answer is that they cannot – it is physically impossible to look at so many cameras. Even if these multiple views were squeezed onto large monitors, they would probably be unusable for detection requirements. There are very few sites where operators have a manageable number of monitors in front of them which also represent the total number of cameras. On the positive side, such a high ratio definitely does lead to success. The Metro Police operations in Cape Town being an example of this.
There is no standard rule of how many camera views operators can view. Research conducted by the Home Office in the UK shows that the chance of picking up even a simple event such as a brightly coloured umbrella in the sunny streets of a town centre goes down appreciably as the number of monitors increase. Similar effects show in research by the TNO-FEL in Holland, showing even small increases in the number of monitors can lead to less detection. Certainly the conditions which the cameras are viewing will have an impact on how well operators can pick up incidents – see http://securitysa.com/article.aspx?pklArticleid=3313&pklCategoryID=3.
A further key issue is that while sites identify the fact that they need cameras in certain areas, the actual display of cameras on monitors is often unplanned, or simply put on a display cycle. In some cases, these cycles are not even coordinated and the operators see a bewildering set of constantly changing images in front of them. This brings into focus the importance of camera profiling and reviewing the risk and operational profile of each camera in the system. It is highly unlikely that all cameras are of equal importance all the time. If you can identify which cameras are particularly important during the course of the 24 hours, you can start defining which cameras can be looked at during what times of day. These cameras can then be placed into groups, and scheduled for viewing at the most crucial times. This will effectively give far more valuable coverage from the included cameras than if a random selection was being displayed.
As the risk models for the site are developed and refined, the camera coverage can also be refined so at any one time the best case surveillance is occurring. Despite optimising the viewing of cameras, there are still likely to be cameras that are seen as important, but cannot be included in the core group. These can be called up and patrolled on a regular basis on separate displays to maximise coverage.
While a risk analysis of each camera and a comprehensive camera profile will provide the right information to design an appropriate viewing strategy, there are more basic things one can do to start the process off. A few considerations are given below:
* Which cameras need to be viewed live, versus those for which recorded information is acceptable.
* Where can security personnel indicate if there is a need for viewing an area – if this kind of information can be provided, these cameras can be used only when a response is needed and regular patrols or inspections of the security presence can be substituted for continual viewing.
* When will viewing conditions make the camera usage almost impossible – for instance, when lighting conditions make situations almost unviewable. If the site is not willing to spend money on appropriate lighting or an appropriately specified camera, then it is probably not so important.
* How urgent is the response requirement – seconds, minutes or days and what does this mean for continual viewing needs.
* What motion detection or intelligent video analysis capabilities can be used to bring cameras to the attention of operators rather than requiring constant viewing – note the motion detection itself may need to be trained or adjusted to know differences in conditions, and when this movement detection is relevant is also going to have to be part of the camera profiling.
* Can access control be used to highlight viewing needs – ie, when certain people are entering an area and their status indicates that they need to be constantly monitored.
Optimising which cameras need to be subject to live viewing and balancing this with motion detection activated camera views is an important consideration. At any time, having continual and excessive switching of camera views in response to multiple false alarms is only going to make the viewing process worse. I have known operators to switch off monitors rather than have a constant distraction to their viewing because of an excess of motion detection alarms.
As indicated, these considerations are not a substitute for a comprehensive risk analysis. However, the more the viewing is optimised the more results one can get from the system, and the better the capital return on investment. This approach does require you to ensure that operators know and understand the reasons for those camera views being there, and what to look for in those areas. It also means that you need to have a CCTV system that is capable of allowing cameras to be grouped and displayed on request for viewing purposes. For service providers, a simple test is to ask the operators in a control room why particular camera views are being displayed. If they cannot answer in a satisfactory manner, the service being provided needs improvement.
Dr Craig Donald is a human factors specialist in security and CCTV. He is a director of Leaderware which provides instruments for the selection of CCTV operators, X-ray screeners and other security personnel in major operations around the world. He also runs CCTV Surveillance Skills and Body Language, and Advanced Surveillance Body Language courses for CCTV operators, supervisors and managers internationally, and consults on CCTV management. He can be contacted on +27 (0)11 787 7811 or [email protected]
For more information contact Craig Donald, Leaderware, +27 (0)11 787 7811, [email protected]
© Technews Publishing (Pty) Ltd. | All Rights Reserved.
printer friendly version