Welcome to the
"Coppers Corner"
section of
Doktor Jons

Guide to Closed Circuit TV

Doktor Jon does his bit to help
the Police with their enquiries.

So would you like to play "Spot the CCTV Camera?". Eagle eyed visitors may recognise the profusion of street furniture, surrounding a single heritage dome camera keeping watch over part  of Londons' prestigious Oxford Street shopping area.
Police999.com ... The information website for U.K. Law Enforcement professionals.
TRUSTED - Target Recognition Using Surveillance Technology for Evidence and Detection - A campaign to improve the effectiveness of existing video surveillance security systems.

A Crime Prevention Officers Top 10 CCTV Tips

To get the best out of a CCTV security system isn't really rocket science, but there are a number of common mistakes which if correctly addressed can make all the difference:-

1) What's the system for?
In order for the 'client' to make best use of their CCTV equipment, they must decide exactly what it's intended to achieve (have a look at CCTV
System Design).

The golden rule is to try and optimise each piece of equipment to a specific defined task; so in practice, trying to multi task a CCTV camera generally means it doesn't do anything properly.

2) Locating the cameras
Imagine the camera is looking at the target through a one metre long tube. The trick is to fix the camera in a position where the smallest diameter tube can be used (in other words, any targets will ideally be moving in a narrow zone towards the camera - a technique which
Doktor Jon loosely refers to as the "Cone of Containment".

3) Choice of lens
After inappropriate camera locations, the biggest single mistake made by installers is to fit the wrong lens on the camera. Most installers use wide angle lenses, which cover larger areas but do not generally provide recognisable images of suspects, for long enough on screen. Standard or Telephoto lenses are usually the prefered option
(info on lenses).

4) Camera mounting
Why oh why do installers insist on mounting CCTV cameras up with the gods. Unless the camera is particularly prone to attack, indoor mountings should ideally not exceed 2.75 metres (or 9 feet), and external units 4.25 metres (14 feet). Generally the higher you go, the less efficiently the camera performs.

5) Recording the pictures
Always try and set the Time Lapse Video to the shortest practical setting (normally 24Hour) and restrict the maximum number of cameras connected through a multiplexer; the more cameras, and the longer the record setting, the bigger the time gap between recorded images. If using a DVR, try and stick to the maximum recording resolution, at a minimum of 4 frames / second (per camera). With a larger hard disk, increase the frames / sec. setting to perhaps 12.5 fps ( or if particularly blessed with a large hard drive, set to real time at 25 fps for U.K./Europe, 30 fps for US standard equipment)

CPO's Top Ten CCTV Tips - continued >>

The unique "TRUSTED" National CCTV Improvement Campaign

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