CCTV operational requirements
September 2009, CCTV, Surveillance & Remote Monitoring
New CCTV operational requirements manual reflects industry trends.
In 1996 the Police Scientific and Development Branch (PSDB) of the UK Home Office developed a document outlining Operational Requirements for CCTV. Under the guidance of Jim Aldridge, it was the first major thrust to professionalise CCTV installations and operations.
Mainly focused on the town centre operations in the UK, it had relevance to just about any CCTV operation. A somewhat controversial cover of the first edition had a thief wearing striped clothing and an eye mask creeping past a sleeping CCTV operator with his cap over his eyes and feet on the desk – it was designed as a wakeup call for the CCTV community. There have been a number of revisions to the Operational Requirements document since then and the covers have changed, but the Home Office still produce what is one of the defining documents on approaching CCTV installation and operation.
The most recent document, CCTV Operational Requirements Manual 2009 authored by N. Cohen, J. Gattuso, and K. MacLennan-Brown has been released. It has some interesting changes which reflect the underlying changes in the industry. There has been a general revision and upgrade of much of the content, but there are also some aspects that reflect newer developments in the industry. One of the key developments has been the changing of the Detect, Monitor, Recognition and Identification definitions that form an important part of describing expected figure size of personnel on screen. These have formed a guideline to many operations including those in South Africa. Indeed, the well recognised Consumer Goods White Paper on the use of CCTV highlights these in the document. These definitions have been changed to:
* Monitor and Control – A figure occupies at least 5% of the screen height and the scene portrayed is not unduly cluttered. From this level of detail, an observer should be able to monitor the number, direction and speed of movement of people across a wide area, providing their presence is known.
* Detect – At 10% of available screen height, after an alert an observer would be able to search the display screens and ascertain with a high degree of certainty whether or not a person is present.
* Observe – A figure should occupy between 25% and 30% of the screen height allowing characteristics such as distinctive clothing to be seen, while monitoring activity surrounding an incident.
* Recognise – At least 50% of screen height, viewers can say with a high degree of certainty whether or not an individual shown is the same as someone they have seen before.
* Identify – With the figure now occupying at least 100% of the screen height, picture quality and detail should be sufficient to enable the identity of an individual to be established beyond reasonable doubt.
These changes in figure size definitions seem to have come about as a result of reviewing police viewing strategies and needs. They have certainly caused debate in the UK, along with changes to the Rotakin camera evaluation tool which has been made more operational and includes more realistic test images. For example, newer Rotakin images of different ethnic head images are used not only to check whether a camera view can identify a face, but accurately describe gender and ethnic group.
Changes have also been highlighted as camera technology has developed. For instance, the Requirements manual highlights that “since the influx of digital systems to the CCTV market there is now variability in the capture, recording and display resolution. So a Recognise requirement can no longer be simply equated to a 50% screen height. For instance, through the use of megapixel cameras and high resolution displays it is now possible to provide the same image resolution as before using a much smaller physical percentage of the screen,” (p. 10). Conversion tables have therefore been devised which give equivalent percentage screen heights for different digital resolutions.
The Requirements document also highlights technology changes and implications in other ways. It comments, for example, on how video should be exported in its native file format (ie, without converting between formats) to maintain image quality. This has implications for some users of digital systems who have difficulty in exporting to alternative formats. The document also comments that no additional compression should be applied during the export process to preserve quality – again something that may be difficult for some systems where this is the only way in which evidence may be able to be generated and distributed.
The greater use of IP cameras has also been recognised with an additional section, as has transmission through networks, the Internet, and various forms of wireless including WiFi, WiMax, and 3G HSDPA. Control room ergonomics have also gained attention, for instance the authors note that, “however much time, effort and expense is put into the correct installation of the CCTV cameras and lighting, most of it will be wasted if the viewing area is poorly designed.” The number of monitors that an operator has to view and their relative size and distance from the monitoring station are key factors in effective monitoring of CCTV. While I disagree with the authors’ comment that operators can handle 16 monitors at a time, the content is nevertheless valuable.
The final section of the 2009 document expands on the Design and Commissioning area. It includes comments that, in particular, tests should be carried out to verify:
“* Camera’s field of view.
* Image detail.
* Live and recorded image quality.
* Storage time provided by the system.
* Operation of the alarms and motion detection features.” (p. 48).
The authors go on to state that some sample video should be recorded and exported from each camera, they emphasise the relevance of using a live target for testing, and highlight the review of recorded video to see that it lives up to quality.
The CCTV Operational Requirements Manual 2009 is a document that everybody involved in CCTV should read. It is an extensive review of the area and relevant issues. Those involved in CCTV may well have exposure to many of the concepts already, and it lacks some substance in areas that people have worked extensively on where lessons could have been included. Nevertheless, the manual provides a structured framework with which to design, install, and evaluate CCTV systems. It has been brought up-to-date on current issues, and remains a highpoint of the contribution that the PSDB and UK Home Office have made to the standards of CCTV implementation internationally.
The manual can be downloaded from: http://scienceandresearch.homeoffice.gov.uk.
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@example.com