Lighting is a critical aspect of surveillance.
Run through this quick 10-point check every time you specify or install a CCTV system.
1. Is white-light or infrared illumination required?
2. Ensure the horizontal angle of illumination covers the full field of view
To provide high quality images is essential. Simply match the illumination to the field of view of the lens using a lens calculator.
3. What is the maximum distance to illuminate?
Specify the illuminator model based on the illumination angle and distance required.
4. If white-light is needed, ensure that colour corrected white-light is used.
Check that red, green and blue colours can all be seen accurately during night-time operation.
5. If Infrared is needed specify the wavelength carefully.
Lower wavelengths such as 850 nm provide greater distances. Longer wavelengths such as 950 nm provide covert illumination but achievable distances are reduced and there is an increased risk of focus shift between day and night.
6. Consider the maintenance and running costs of the illumination system.
Ensure that long life, low consumption lighting is used.
7. Consider the positioning of the lighting.
It should be fitted so that no camera is looking directly at a light source. The best solution is mounting the illumination at the camera position. Also, consider any line of sight obstacles. As light travels in straight lines, any obstacles such as overgrown foliage will create shadows.
8. Consider the camera and lens.
A high performance camera and lens will provide higher quality images with CCTV lighting. Lower performance camera and lens combinations will require additional lighting to provide similar results.
9. If the illumination is being used with a fully functional dome camera then a choice must be made between wide angle illumination, local area illumination or target area illumination.
Wide-angle illumination is preferential as it can provide 360° lighting for the dome.
10. Is light pollution a critical factor?
Using white-light ensure that the illuminators are pointing down to minimise light pollution. If no light pollution is permissible then infrared lighting must be used.
If the exact field of view is unknown, adaptive illumination products can be used to provide vari-focal lighting.
Even illumination – every CCTV lighting system should provide even illumination.
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