|
March 2014 |
This note discusses a new feature of video surveillance cameras called Adaptive Infrared (AIR). The camera must have built-in IR LED and is zoom-able as the pre-requisites.
- The IR LED has a finite strength to cover a pre-defined distance such as 20m within an angle of such as 50 degrees. The IR beam could be too weak mostly or too strong sometimes. Too weak- the camera cannot capture or identify any object at night. Too strong- the object in question may be washed out in the video due to over-exposure. For example, a traditional IR LED camera may capture an outline of a person 10 meters away but when that person moves closer to the camera, the person shape may be washed out due to strong IR intensity. We wish the IR LED can adjust its intensity by following the distance of the focused object. This capability requires some intelligence but if not all most cameras do not have it.
- Change the camera to one with zooming capability. When the camera zooms in, it will automatically adjust the IR LED intensity to focus on the area that it zooms into. The IR beam will be concentrated in one area to narrow down the beam angle and extend the range to cover the zoom-in area. When zooming out, the camera will re-adjust the illumination back to cover the wider area, making sure that there is enough IR illumination in either near or far view. This capability is called Adaptive Infrared.
- Compucon camera models CAB67 and CAB87 are among the first batch with this capability.
Other Varieties of IR LED Features
- Built in IR LED (without Adaptive capability)
- IR Filter Cut-off (to switch off the optical sensing capability in order to focus on IR sensing, and vice versa)
- Passive IR for detecting temperature of objects within a close distance (used for office security system). An Compucon model is equipped with PIR.
- IR Illuminators are external and not built inside the camera enclosure. They provide much stronger IR beams than built-in type because there is no constraint imposed by the camera on heat generated and physical size.
With Adaptive Infrared
|
Without Adaptive Infrared
|
 |
 |
|
END
|
