So quotes Prof. Martin Gill in his recently published 190 pages or so findings for the PSDB evaluating the effectiveness of CCTV.
Do we all agree with Martin's findings or do the studies make us all feel rather indignant and slighted? I suspect there is a strong degree of truth in the report and an obvious time for us all to get our house in order.
The domestic market
We practitioners in the CCTV industry have always followed in the footsteps of our polished uncle and his large entourage, that is, the television broadcast industry and the television domestic market.
VHS recorders, camcorders and DVDs were not pioneered for the CCTV industry; they were developed for the professional and domestic television sectors. What has always happened is that our special entrepreneurs have seen the emerging technologies and adapted them for our use in the surveillance industry.
Blu Ray is the up and coming technology that the major players (Sony, Sanyo, JVC, Panasonic, Thompson, et al) have adopted to provide even more recording time on our DVD recorders and to make them affordable for everyone at a quality most home viewers are very well satisfied with.
So, why are many CCTV systems in use today producing pictures of a quality far less than the users' expectations?
Fit for purpose?
Are the many hundreds of different DVRs flooding the market really fit for purpose?
Within the vast range of digital video recorders now available there is a range known as 'VCR replacement'. Not only do they take up the same space as a regular time-lapse videocassette recorder, but also they are designed to replace both this and the ubiquitous multiplexer that feeds it interleaved pictures from, for instance, 16 analog cameras.
Choosing which seemingly uncomplicated DVR is best for you can be as daunting as selecting the right mini-Hi Fi from the bewildering array of flashing lights and silver buttons on show at the local electrical supermarket.
Our independent testing of DVRs at the Tavcom evaluation workshops have shown how difficult it is to compare DVRs that are superficially very similar, because of personal preferences and the myriad of particular features and functions that are too numerous to investigate and draw comparisons. This is still true even where the innards have the same origin but are engineered into a different product (suppliers buy from the same source and put their logo on the front).
We feel that the most significant findings here are the unexpected cropping of images and the accompanying loss of raw information. Following this, the quality of electronic processing governs resolution of fine detail and the minimising of unwanted colours added to the picture. After this, the heavy compression of image data greatly affects the DVR's raison d'être; to provide satisfactorily clear CCTV pictures. The latter is often a disappointment, unless you are prepared to invest in voluminous primary storage, backup and export mechanisms. The colour, shape and number of flashing lights on your DVR will remain items of personal preference.
Is this a problem? Yes! Instead of the security CCTV industry taking a giant step forward in picture quality and update speed, most of the manufacturers have maintained the same inherent weaknesses of the multiplexer/VCR combination.
Weakness? A major issue resulting in the poor pictures retrieved from the traditional VCR/multiplexer is still mainly with us.
The weaknesses are:
* A/D (analog to digital) converters are basically the same as those used in the previous selection of CCTV multiplexers.
* The images are cropped vertically and horizontally by as much as 20% to enable picture update rates to be made acceptable. (The outcome of this is that what you see is not necessarily being recorded.)
* Limits the picture resolution by only not recording the full picture image; and many quote 25 images a second (IF only one camera is being used) but do not say that half of the vertical resolution is not captured.
Why can we not have the same quality picture reproduction as we get with DVDs?
Well you can! It is just that you have to search out the manufacturers that can provide images that may suit your needs.
Or do we have to accept that there is a two-tiered market in the CCTV industry - those cheap and cheerful systems and those with a more discerning need?
With time-lapse video cassette recorders (VCRs) the only thing you could vary was the time it would take to go from one end of the tape to the other and this was usually from 3 hours (realtime) through 24, 48, 72.... to 960 hours (40 days). If you needed to record more than one picture you would need more VCRs or a video multiplexer.
Digital video recorders (DVRs) have combined the functions of multiplexing and video recording, but not only that, they also have the flexibility in picture quality and video storage and the ease of retrieval management.
With DVRs the main variables are:
* The capacity of the hard disk for video storage, measured in gigabytes.
* The picture quality or image file size, measured in kilobytes.
* The number of pictures per second per video input.
* The number of inputs being used.
Hard disk
Most manufacturers offer a choice of disk size, but generally disks with larger capacities take longer to fill. Disk sizes vary depending on whom you to speak to and the latest that has just been released! Many gigabytes and several terrabytes are very common today.
Remember, the total capacity of the disk may not all be available for video recording, some may be set aside for audio or data.
Picture quality
The picture quality or image file size determines the rate at which disk storage space is taken up. High quality takes more space than low quality. Typical file sizes will vary from 5 Kb for very low quality to 50 Kb for higher quality pictures. Other factors that can affect the file size are the number of changes that occur in successive pictures and the type of compression used. On most recorders the file size can be adjusted according to the requirements of the system.
Pictures or images per second (pps) or (ips) or even (fps)
The number of pictures or images stored, per second, also affects the rate at which disk space is used. 50 pps takes more space than 1 pps. Where there is rapid movement or more detail in a scene more pictures per second may be required.
Number of inputs
The number of input channels being used has a direct effect on the rate that disk space is used. With 16 inputs taking twice as much space as eight inputs. Well that is what you may think, but some manufacturers allocate a finite number of pictures per second, say 50 pps, and then divide it between the number of inputs. So 50 pps divided by 2 will give 25 pps per input, but if there are eight inputs there will only be 6,25 pps.
Some DVRs do not allow you to set up all the defined parameters independently and often defaulted to what the equipment designers thought was the best compromise.
The weakest link in any CCTV surveillance system is the DVR (or Mux and VCR combo). A major consideration to deploying a DVR is to retrieve the information on another occasion to provide intelligence and evidential material in a court of law.
As Prof. Gill indicates in his report, the vast majority of systems installed totally fail to be fit for the purpose and are pretty useless for the police and criminal justice system.
As an old colleague put it recently, "the criminal fraternity are now fully aware that CCTV is so poor that the chances of most systems ever producing video footage fit for purpose and meeting the expectations of the user, is on par with winning the six numbers in the lottery!"
Let us raise the standards and successful prosecutions will begin. There is absolutely no reason why we cannot change the way we operate for the better.
So perhaps you need the CCTV consultant
What is the perfect pen picture of a CCTV consultant? Should the following points be the mandatory minimum skill level?
1) Technical ability to at least level 4 to guide users wisely and interpret installer's specifications and manufacturers data sheets as well as to commission a system correctly.
2) Legislative skills to guide and ensure the correct Codes of Practices, signage and operational procedures are in place.
3) Project management skills to bring together the many facets of a CCTV project.
4) Control room ergonomic and human factor skills.
5) Communications ability to facilitate meetings between user, installer and interested parties.
6) Understand lighting and emergency lighting parameters.
7) Able to determine planning and other officialdom.
Frustrated users
We have the technology, we have the experience and we have the need to provide equipment that is fit for purpose. Users will benefit from better picture information, vendors will increase their bottom line profits and the installers will not need to be kept hauled back to the site for tweaking exercises!
Associations and governing bodies should be working together to provide help for the many thousands of users wanting to use the technology but users are too frequently being sold the proverbial 'pup' the first time for the purse strings to open again to replace systems that were just not fit for purpose.
Will you be one of those that are willing to learn and willing to help teach others?
Then when we have it nearly right and fit for purpose perhaps then we can ask Prof. Martin Gill to review the use of CCTV in our professional world and trust fervently that the outcomes result in the statement 'CCTV is an excellent deterrent for criminals'.
For more information contact Mike Tennent, Tavcom Training, [email protected]
Mike Tennent is the founder and managing director of Tavcom Training, a UK-based provider of security systems training. Tavcom teaches the selection, installation, operation and maintenance of all electronic security systems including CCTV, network IP, access control, perimeter defence and intruder alarms. Its students include installation engineers, control room operators and security managers at all levels. Mike can be contacted at [email protected]
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