The Art Of CCTV Design

Gardner Security recently installed a CCTV camera system for a water utility in southern England. The system comprises of nearly 50 cameras, all of which are high definition colour monochrome type.

Click here to view a slide show of the CCTV installation.

Colour cameras will provide the best images during the daylight hours, however, not even the human eye can recognise colour when the light reduces beyond a certain level. So a monochrome (Black & White) camera is better for night time surveillance.

For this reason, Gardner Security Ltd installs cameras which will switch between colour and monochrome dependant on the light level. Where there is very little or no light, lighting has to be provided. In these instances the use of Infra-Red lighting is used.

This type of light is invisible to the eye but able to be picked up by the camera. You have to be sure that you have the correct camera and lens for this as some will not resolve an infra-red image.

The cameras used in this installation are of the highest quality and will not only resolve the image, will produce images in low or no lighting environments which would be superior to most daytime images produced by most other systems you would have seen.

Some of the cameras seen in this installation are speed dome cameras. Again the domes are of the highest quality with excellent image quality. A speed dome has the ability to pan, tilt, zoom and focus through 360° this can be either manually controlled or automatically controlled to cover a large area or to view and area of activity.

The camera will go to any position programmed within 1 second of receiving the command. When detection is used, person enters an area covered by detectors the camera will automatically look at that area and show the person on the screen. Where multiple detectors are used the camera or cameras will automatically track an individual around the whole site ensuring you don’t lose sight of the intruder.

Should this happen, the system will send video images of the intruder to a 24hour monitoring centre where there activity will be observed and the appropriate action taken. These systems will significantly reduce the cost of guarding on site and you can be assured that the system will not sleep and the detection will cover the required areas continually.

Where large areas need to be covered by surveillance cameras, thought has to be given to the type of cable used. Different types/grades of cable will reduce the video signal when run over certain distances. In this installation the cable used is Fibre Optic.

As you may know Fibre Optic cable is glass and will transmit video signals over significantly longer distances than copper cable without affecting the video signal. Fibre Optic cabling and termination is a specialist skill. If the cable is not terminated correctly it will reduce the video signal and if the cable has not been correctly installed it will break! If you are considering Fibre optic cable ensure that your chosen contractor has the required skills to install it correctly.

This site is split by a railway line, and building the wrong side of the line has no direct cable routs or telephony installed. So how do you get your cable across? The answer is simple, don’t! In these situations you may find that rather than cross over the top or under railway lines, roads or motorways it is better to install a microwave link.

This will transmit your video and telemetry signals over the obstruction without the need to physically connect cable from one side to the other. Microwave links have improved over the years and unless you are transmitting signals over a number of miles the links are quite small and unobtrusive.

If you are local to the south coast and want to see a small link of this type, there is one we installed at Gosport Ferry Ltd, This microwave links the Gosport pontoon with the nearby office. The local council had recently renewed the paving in this area and would not allow us to install a duct to pull the cable through so the only other guaranteed solution is microwave.

Our customer also has a requirement to monitor vehicle access and egress on the site so we installed two ANPR (Automatic Number Plate Recognition) cameras. These are linked to a database where each vehicle and its number plates are recorded 24 hours a day. This data base can be interrogated to find a vehicle and to then track its movements on site through the other cameras.

The recording of the images is an important aspect; you need to ensure that your recording equipment is capable of holding the information from each camera for the required amount of time. Please don’t guess, we have seen many people purchase recording equipment only to find when they need to find a recording it has been erased because the there was insufficient disk space for the system.

We would not recommend the use of video tape recording as it will wear out and you will have to continually change tapes. On this installation we have specified 6.5TB of video storage. This is distributed between the two control locations. This will provide the required recording for all cameras and will enable the customer to easily access the information.

All in all this is a very complex installation, but one which has been commended by all who have seen it.

In the pictures you will see the system from pre-build and bench test state through to the finished installation.

If you have any questions about any of the information provided in this article please feel free to send them to enquiries@gardnersecurity.co.uk