Published on 9 Jun, 2010
When it comes to maximising the benefits of CCTV, a key priority, in the first instance, must be to look at the frontline where the all-important images are being captured.
Whether being used for commercial or public space surveillance, as the eyes of a solution, cameras must be both fit for purpose and positioned so they are able to see, at an appropriate level, what is actually going on in a designated area, with the right amount of illumination also a prerequisite.
This focus on how cameras are applied may seem logical, however the point is that where, in a minority of cases, common sense does not prevail a solution is liable to fall at the first hurdle, severely constraining its ability to detect crime and provide useful evidence. Certainly this is not a situation which is in the best interests of a specific user; what they are attempting to protect; the potential for authorities to secure convictions or, for that matter, the wider reputation of CCTV.
Given the technology now available, the multitude of standards and best practice guidance which refer explicitly to CCTV cameras - BS8418 being a case in point - and the options for illuminating the immediate area, there can really be no excuse today for poorly defined and implemented CCTV.
Paying regular attention to the status of CCTV cameras is essential for the long-term viability of a solution
Captured on Camera
Whilst not all CCTV applications mirror those of remotely-monitored, detector- activated CCTV, the recommendations of the BS8418 standard with regards to what a camera should be able to see to verify an event are particularly instructive. For a specific field of view it suggests that for verification purposes this should be set to a 1.6 metre high target filling a minimum of 10% of the picture height. When it comes to the actual recognition of an intruder then the suggestion is that larger image sizes are required where the target should, as a minimum, be more than 50% of the picture height.
Turning to camera positioning, of critical importance for detector-activated CCTV, is that the field of view coincides with the area being covered by a specific detector. If there is a disconnect between the two then, should a detector be activated, the mis-aligned camera view available to the RVRC (Remote Video Response Centre) will, in all probability, fail to show the cause of the alert so undermining the whole point of having the solution in the first place.
A Brighter View
With regards to illumination, this is undoubtedly a determining factor in the performance of CCTV cameras in areas, or at times, where natural light is not available. Where artificial illumination is being used it is important that it is not shining directly into a camera as this will have a negative impact on the clarity of the resulting images. As well as standalone illumination we are now seeing integrated units being brought to market which combine cameras and IR illumination. The advantage here is that the point of view of the camera is always illuminated whatever direction it is facing.
|Illumination is a crucial factor for optimal CCTV performance|
Advances in technology are certainly helping cameras to cope with more testing lighting conditions, for example, those which feature a WDR (Wide Dynamic Range) sensor are being increasingly deployed in reception/entrance areas where it is important to be able to correctly expose shadows and highlight so the right level of detail can be seen, even when backlit.
Setting the Boundaries
An additional point to be made in the context of CCTV cameras - alongside the imperative that they should effectively cover key areas - is the need to prevent monitoring outside of a site or cameras being used inappropriately.
Care needs to be taken with cameras to avoid their field of view overlooking public areas. As well as physically limiting what a camera can see it is also possible to adopt electronic methods such as privacy masking to block out portions of an image/scene. With the advent of Chip and PIN, at the BSIA, we produced guidance on the positioning of CCTV cameras in relation to Chip and PIN terminals. This highlighted best practice to prevent retail staff misusing CCTV in the Point Of Sale (POS) area to gather footage of customers keying in their PIN numbers during transactions.
Paying regular attention to the status of CCTV cameras, once everything is up and running, is essential for the long-term viability of a solution. In the event that a camera fails, steps should be taken at the earliest possible opportunity to plug the gap by replacing and/or repairing the unit. The message is that such failures should not be ignored and, certainly, the last thing anybody wants is to have a major incident adjacent to a camera which is not operational.
In Support of Best Practice
So to conclude, today's CCTV cameras are certainly extremely capable, however as we have seen above it is not just the technology built into them that is important to their ultimate success, but perhaps just as critical is how they are set-up and maintained on-site.