By: Arthur Cooper
Submitted: 2010-08-04 08:30:04 | Word Count: 664
A camera mounted infrared illuminator is used with most night vision infrared digital video surveillance and security cameras to provide invisible light that is used to create an infrared digital video. The illuminator is normally aimed in the exact same direction of the camera lens so that it can provide infrared light beams to illuminate the target area. Infrared illumination can be “seen” by the camera, but can not be seen by the human eye.
Let’s take a closer look at how a night vision infrared digital video security camera works in order to appreciate the need for the camera mounted infrared illuminator.
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A night vision infrared digital video security camera can produce high quality color video footage when there is enough visible light present. When there is not enough visible light present or when in total darkness, a sensor on the camera switches it into the infrared mode. Digital video recorded under the infrared mode is high quality video footage as well, but is monochromatic or black and white, since infrared light does not emit color.
These cameras create a video image by using one of two sensors that convert light energy into electrical energy that can be quantified and used to create a digital video picture. The sensors that are normally used are the Charged Coupled Device or CCD, or the Complimentary Metal Oxide Semiconductor or CMOS. The camera lens focuses the light from the image onto the sensor which then converts the light image into an electronic image which can be viewed on a monitor or stored as a digital video file.
Both the CCD and CMOS can be constructed with various sensitivities to light. Some cameras can produce full-color, high quality digital video with as little as .002 lux or less of light. These cameras are usually called day/night vision cameras and still require visible light to operate properly; they are infrared sensitive cameras.
A camera mounted infrared illuminator is required on night vision infrared digital video cameras to provide plenty of “light” to illuminate the subject. However, in this case the light is actually infrared radiation from the near infrared spectrum. This light or radiation has a similar effect as a flood light or spot light would on a normal visible-light digital video camera.
Most camera mounted infrared illuminators are created from several infrared Light Emitting Diodes or LEDs. The LEDs are able to create a sufficient amount of radiation that can be focused in the direction of the camera’s field of view. The advantage of using LEDs is that they use a relatively low amount of electrical energy and are small and compact.
The LEDS are normally arranged in an array that surrounds the outside of the camera’s lens or is in a grouping off to the side of the lens but aimed in the same direction as the camera. Generally the more LEDS used the greater the angle and the longer the distance of the effective infrared field of view. For this reason, every night vision infrared digital video camera has an effective target range. I
f you are considering the purchase of an infrared night vision camera, be certain that the camera matches the range that you need for the job. There are a variety of different cameras available based on their effective range. Range values for cameras usually begin around 20 to 30 feet with cameras that have ranges of up to 200 feet or more. Cameras are more expensive for higher ranges, because of the extra LEDs that are used for the camera mounted infrared illuminator.
Some cameras ranges and angle of field of view can be extended by using additional infrared LED illuminators. However, these are not camera mounted infrared illuminators; they are mounted separately on their own and must be manually adjusted to ensure that they are aimed properly at the field of view of the camera.
Camera mounted infrared illuminators are an integral and necessary component of any infrared digital video camera. They supply the infrared “light” or radiation that is needed to illuminate the target area for the camera. Normally, the source for this radiation is an array of infrared LEDs that surround the camera lens or are located on the camera. Additional LED illuminators can also be purchased as accessories.
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