Infrared illumination is an essential requirement for effective nighttime surveillance. The traditional pan and tilt approach to mounting infrared illuminators offers the distinct advantage of permitting the infrared beams to follow the movement of the camera. Despite their flexibility and aesthetic appeal this is not possible with fully functional dome cameras.
Basic Solution: Fixed Domes
Dome cameras can be divided into two categories, fixed domes and fully functional domes. Fixed domes are often vandal resistant and used for short-range surveillance purposes. Because the unit is fixed the low light issues are similar to those of other standard cameras. In low light, or zero lux conditions, fixed domes will require additional lighting. Typically, infrared provides the best, most practical and cost effective solution.
To ensure full coverage of the scene, the infrared illumination must be matched to the field of view of the camera/lens combination. Narrow beam illumination should be used to match a narrow field of camera view and wide beam illumination should be selected to match a wide field of view. Failure o match the camera field of view and the infrared beam can dramatically reduce system performance.
Many dome systems have optional “smoked” domes that can reduce the infrared illumination that reaches the camera by as much as 70%. When smoked domes are employed increased infrared illumination levels may be required to compensate for the infrared attenuation of the dome.
Advanced Solutions: Fully Functional Domes
The main challenge with a fully functional dome is the inability to mount infrared illuminators on the moving part of the dome. To overcome these problem mounting bracketry has been developed which fits around the dome pole and makes it simple to install infrared illuminators.
Solution One: 360-Degree Wide Area Illumination
One answer is to provide 360-degree infrared coverage so that so that there is sufficient infrared illumination to enable the camera to record the scene effectively. This requires a high level of investment since full 360-degree coverage would require locating eight 45-degree infrared lamps. Domes mounted on the corner of a building would require only 270-degree coverage (six 45-degree infrared illuminators) and domes mounted on walls would require only 180-degree coverage (four 45-degree infrared illuminators).
Solution 1A
Solution 1B
Solution 1C
Fully Functional Dome with 360 degree coverage
Fully Functional Dome with 270 degree coverage
Fully Functional Dome with 180 degree coverage
Bracketry System for use with Dome Cameras
The bracketry design fits right around the dome pole and makes it simply to install infrared illuminators. The system allows infrared illuminators to be targeted in any direction – 360 degrees - with pole mount applications, 270 degrees or 180 degrees with wall-mount applications.
Solution Two: Specific Target Illumination
An alternative solution to providing full coverage is to provide “target specific” infrared illumination. With this approach infrared is used to illuminate specific areas of risk rather than the whole area being viewed by the dome camera. During the full 360-degree rotation of the dome camera, there may be only two or three specific targets that need to be viewed. Infrared illuminators may be mounted on or around the camera pole to continuously illuminate these targets.
Solution 2
Distant Object
Door
Fully Funtional Dome with target specific IR coverage
Gate/Fence
Solution Three: Local Illumination
A third approach is to locate the infrared illumination above or near to the specific target. If the camera angle of view and the infrared illuminator beam angle are properly matched, local illumination is a viable alternative to locating the infrared illumination in the vicinity of the camera.
Solution 3
Fully Functional Dome
Target Area
<--- 100 metre --->
Infrared located close or near to target
For both target specific and local illumination it may be possible to trigger the infrared illuminator via a pre-set on the dome. In addition, when locating the infrared illumination above or near to the subject a PIR detector may be used to activate the infrared illuminator.
DWB4 Dome/IR Wall Bracket, 4 way "Technical Drawing" ,40kB pdf file.
DCB4 Dome/IR Corner Bracket, 4 way "Technical Drawing" ,40kB pdf file.
DPB4 Dome/IR Pole Clamp Bracket, 4 way "Technical Drawing" ,38kB pdf file.
DPB2 Dome/IR Pole Clamp Bracket, 2 way "Technical Drawing" ,37kB pdf file.
Bracket Dimensions "Technical Drawing" ,25kB pdf file.
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DWB4 Dome/IR Wall Bracket, 4 way "Technical Drawing" ,40kB pdf file. 