The Camera System

To maximise the benefits of a video surveillance system, the camera set-up has to be right. The recording system can only record what the camera system gives it - a poor image from a camera will be stored as a poor image on a recorder. Minimal enhancement can be applied to video images, as a finite amount of picture information is captured and stored. For example, zooming in does not reveal any further information - it will only turn a small blob into a big blob. To get the best results from your system, consider the following:

Camera Placement

It is recommended that you assess your surveillance requirements to ensure adequate coverage. Where are the main entrances/exits? What are the main target areas? Where would best offender identification be obtained?

The best images for offender identification are front-on and close up. High angled cameras predominantly capture the tops of heads, and offender behaviour is such that hats, beanies or head dress are often worn to mask or obscure faces from these angles.

A wide image is good for viewing overall movement or action, but poor for offender identification, as offenders are placed at such a distance from the camera that only a small amount of the overall picture resolution is dedicated to their images. The installation of multiple cameras is a solution to the problem of coverage versus identification.

Cameras within easy reach can become targets for vandals. Cameras can't see through physical obstacles such as chewing gum, paint or dirt, so placement out of view and/or out of reach is ideal. Poorly placed banners, advertising, shelving, and decorations can also obstruct camera views, rendering the resultant images worthless.

Camera Set-up

Camera resolution, lens type, focus and exposure must be addressed to ensure a successful installation.

The minimum recommended camera resolution is 320 television lines. (This is roughly half the resolution of a broadcast television image).

The lens itself must be compatible with the camera, display minimum image distortion (i.e. bending/warping), display minimum image discolouration, and provide adequate coverage of the target area.

Focus is paramount. Nothing can compensate for a poorly focused camera system - it will produce blurry, unusable images.

The camera should be able to cope with the range of variable lighting conditions in its field of view over 24hours per day, 365 days of the year.

Camera viewing doors that open and close into the outside world must be able to quickly vary their amount of light intake in order to maintain a useful image.

Lighting Conditions

To ensure the correct exposure of an image, controlling the camera's environment is often necessary. The camera may need assistance through the addition of extra lighting - this is often the case after hours, or in poorly lit areas. Images lit predominantly from behind appear as silhouettes. In this situation, compensation from other lighting sources is required to produce neutral lighting and resolve picture information. Conversely, strong light sources (e.g. the afternoon sun) sometimes need to be shut out to preserve optimum lighting conditions.