Monday, September 6, 2010

Types Of Security Cameras







A security camera can act as a powerful deterrent for would-be intruders or vandals. There are many different types of security cameras on the market, ranging from high-end, high-tech cameras employed by the military and various industries to the more economical versions often seen in convenience stores or that come as part of many home alarm systems. These cameras are designed to meet different needs and environmental conditions.


Infrared Cameras


Infrared cameras are sometimes referred to as night vision cameras because of their ability to capture objects in complete darkness. Humans aren't able to see infrared light because it lies in a different range of the electromagnetic spectrum than visible light, which is discernible to the human eye. Infrared cameras operate using infrared LED lighting installed on the outside lens of the camera. This allows the camera to capture and record images in the absence of regular lighting. If the area is slightly lit, the image is clear as if it were daytime and the picture is captured in color. In complete darkness, images appear in black and white. All objects that have a temperature register in the infrared. Special thermal infrared cameras are often employed by the military to detect insurgents or enemy combatants from a distance.


Day/Night Cameras


These cameras are designed for use in outdoor areas; they can also be used indoors in areas with poor lighting. During the day, a day/night camera delivers color images. As night falls and the amount of light decreases, the image remains clear, although it's not as detailed or as crisp as during daylight hours. Bullet cameras, dome cameras and box cameras, among others, can come with night/day functionality.








Wireless Cameras


A wireless camera works via a transmitter and receiver device. A regular camera, on the other hand, requires two wires, one to connect it to its power source and another to transmit images. Wireless cameras are, by nature, more flexible; they can be placed anywhere. Images can be relayed to a portable DVR device for completely wireless recording. Analog wireless cameras, however, can receive interference from cell phones and even microwave ovens. Fluorescent lighting interferes with the signal as well.


Dome Cameras


These are the types of cameras used frequently in stores and shopping malls. The dome offers protection from both the elements and vandals. Many dome cameras are equipped with smoked or blackened coverings so people can't tell exactly where the lens is focused. There are two main types of dome cameras, fixed and PTZ. Fixed dome cameras stay in one single position, whereas PTZ cameras are more versatile as they can zoom, tilt and pan.


Network Cameras


A network camera is connected to a computer IP network. Cameras capture analog images that are then transformed into digital images and streamed over an IP network via an Ethernet cable. Network cameras are broadcast over the Internet; however, each camera has its own stream and IP address. To view and record a feed, separate software must be installed.

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