CCTV and surveillance: a security manager’s guide
CCTV expert Vlado Damjanovski, Managing Director of CCTV Labs outlines the issues and latest developments surrounding CCTV surveillance technologies and what security managers need to consider when installing a CCTV system.
While CCTV and surveillance technologies are advancing at a rate of knots, a lack of general understanding of the concepts involved and some unrealistic expectations have led to a misunderstanding of the potential of CCTV for the security industry.
When a security manager plans to acquire CCTV capability, the first requirement must be for them to understand the basic concepts of CCTV surveillance systems, which include light, lenses and cameras, followed by video signal transmission, encoding/digitising and then display.
Understanding CCTV requires thorough research into the systems available on the market and an appreciation that ongoing learning and self education are vital.
Security and CCTV technology integrate so many different disciplines that no matter what part of the industry a person comes from, and regardless of their experience prior to joining the industry, they have to be prepared to go through a very steep learning curve. This refers equally to an ex-policeman as well as an ex-IT guy.
If this commitment cannot be made, the security manager will not be able to catch up with the system design, product functionality, or any other wider aspect of a CCTV system design.
A common mistake security managers can make when choosing a CCTV system is to compare products based on price and paper specifications only, without testing them and without real consideration of the long-term investment.
Unfortunately the price is, and has always been, one of the prevailing factors in deciding which system goes in many tenders in Australia. Comparing products based on price and paper specifications is like buying a car without sitting in it and taking it for a spin.
The common and simple argument is a Hyundai that costs $15,000 is not, and cannot be, the same as an Audi that costs $65,000, although, admittedly, both will take you places. The difference is in safety, comfort, elegance, functionality, performance, and at the end of the day how long it will last, which is your long-term investment.
Downplaying Hollywood hype
One of the major misunderstandings of CCTV capabilities that can occur between vendor and customer stems from the trickery of Hollywood. The fact is that the capabilities of real CCTV cannot match what you see on weekly episodes of CSI.
Many customers expect to be able to ‘zoom in’ in the recorded footage an infinite number of times and be able to see number plates and people’s faces, no matter how small they are and where in the field of view. While using some megapixel cameras helps improve this false impression of what you can do with CCTV camera recorded footage, the majority of CCTV cameras are still analogue and of standard definition quality.
This means if a camera hasn’t seen certain details before compression and recording, it is impossible to have such details retrieved using any method, CSI or not-CSI.
The compression question
One of the more confusing issues of CCTV technology concerns compression. So many times I have been asked a question that says a lot about the understanding of compression – what is the file size of the MPEG compression used by so-and-so DVR? There is no such thing as file size when talking about video compression. You can only talk about file size when using image compression; you talk about streaming rate when using video compression.
Video compressions use three dimensions during the compression – the horizontal pixels, the vertical pixels and time as the third dimension. So in order to achieve efficient video compression, a DVR or encoder, needs to have continuous video presence without too many changes in its contents. Such compressions include MPEG1, MPEG2, MPEG4, and H264; these can only be expressed in kb/s (kilobits per second) or Mb/s (megabits per second).
The image compression techniques, on the other hand, are the ones where you can say, “the image file size produced by such-and-such DVR is 20kB, 30kB or 50kB or more”.
‘Decent’ quality requires at least 40kB-60kB. This is the same compression you have on
your digital compact camera, just in the case of CCTV we have many such images
multiple times each second (up to 25).
The uncompressed, but digitised, image (TV frame) of a standard CCTV camera is around 1.2 MB. So, when we say 40kB offers ‘decent’ quality, this is an image that has been compressed 30 times.
Video compression started back in the 1980s with MPEG1, around 1Mb/s streaming for a VHS quality (what we now call Common Interchange Format, or CIF) and includes compression of audio as well.
The popular MP3, for example, is the audio layer of the MPEG1 video compression.
Later on, video compression standards improved with MPEG2, which is used widely for
DVD movies.
Under the ‘hood’, the compression chips (sometimes called ‘encoders’) perform a lot of processing, mathematical discrete cosine transformation number-crunching, motion prediction and various video filtering. We do not see any of that, only the final result, a smooth playback of a footage, or movie, at 4Mb/s (if MPEG-2 DVD quality is the desired result).
Yet, many in CCTV want even more ‘squeezing’ of the signal.
Never forget that there is always a limit on how far you can go with the ‘squeezing’ of the video signal and there is a threshold after which the video compression produces visible artifacts. The trick is in finding a good compromise – compress it enough to save hard disk space when storing (or bandwidth when streaming) but not too much so that you don’t loose precious details in the video signal.
On the horizon
Looking ahead, the rapid developments in CCTV technology present new potential around every corner. One of the next major CCTV breakthroughs will come in the area of High Definition (HD) CCTV, which is more and more becoming a practical reality.
Cameras producing true HD signal at 1920x1080 pixels, in real-time streaming, are already becoming affordable and this will be the next big thing. I know, many would say we already have megapixel cameras which may have even more pixels than the HD resolution, but I am talking about practical real-time streaming, with sufficient quality and bandwidth to offer real time HD CCTV.
As well as HD CCTV, a breakthrough is also imminent with the implementation of intelligent and reliable video analysis in real-time as well as the ability to search and index incidents without human intervention.
I think people will eventually get sick of recording so many terra-bytes or peta-bytes of incidents and not being able to easily find a particular event, a person, or car, or whatever. This is in a way what the MPEG-7 standard is proposing, and time will come when this will be a reality in CCTV.
The CCTV road ahead: understanding and integrating
While a sufficient level of understanding of the ground-level concepts of CCTV has yet to permeate the security industry to the level experts believe is necessary, pathways exist for security managers to rectify this through education. A number of research avenues are currently available including seminars, publications, websites and associations such as the CCTV Certification and CCTV Standards of Australia, of which I am chairman of the CCTV sub-committee.
We are at this stage at the very beginning of this initiative, but so far we have been writing awareness articles in various publications, talking about it in various seminars and presentations, registering forum sites and making it known to the industry by controlled e-mailing and, of course, talking to all the people in the industry we know.
I have devoted quite a bit of my professional time towards education; there should be a bigger choice and this should be a more common knowledge. This is the reason we started talking about the need of CCTV Certification, which ultimately will suggest all known sources around the globe for expanding the knowledge.
But those not yet up to speed on CCTV should not drop their heads. Security managers may not necessarily have to understand it all inside out; this would be the job of their technical people. But it would be good for them to have at least heard, or read, about the topics. That way security managers can participate in discussions about system design and the way they operate.
If security managers are ignorant to all the technological revolutions we are going through they may be left out, dealing only with the time-sheets of their employees, and not the whole security operation of a business. It is also important to highlight here that the whole world is in the same boat – it is not just Australian security managers going through this evolution.
This whole scenario of ‘steep learning’ is not very different from when we first got PCs back in 1980s. There were a lot of people then that did not want to learn all that ‘high-tech’ stuff, but eventually they had to do it if they didn’t want to miss the boat.
And the longer people hesitate to get on board, so to speak, the harder it gets to jump on the band-wagon.
Additional reporting: Justin Grey, Associate Editor
About the author: Vlado Damjanovski is the Managing Director of CCTV Labs, as well as the Chairman of the CCTV sub-committee of CCTV Standards of Australia and a member of the group that coordinates the CCTV Certification initiative. He has published a number of books on CCTV and frequently holds CCTV seminars.