Closed circuit
TV has many uses.
Closed circuit television (CCTV) is useful in many different ways. Familiar uses include home security, casino surveillance, retail security and baby monitors. Consumers should take care when selecting a camera. While the device usage should be a major consideration when picking a unit, a careful survey of the device specifications is also necessary.
Color Specification
The first specification looked at should be whether you need a color camera or not. Color cameras can be more costly, but can also add a dimension of detail to what you are observing. If you need to identify items in the picture by their colors, a black and white camera is useless. Color cameras are often used in retail and casino security, where color of clothing is sometimes used to quickly identify someone.
Imaging Chip Specification
The type of imaging system also greatly impacts picture quality. Many security systems use complementary metal oxide semiconductor (CMOS) cameras. In a CMOS camera each pixel is converted to a digital format individually. This causes a CMOS camera to need the help of on-board amplifiers and noise correction circuitry. This circuitry is most often added to the CMOS imaging chip, which cuts down the overall size of the camera. Cameras that use a charge coupled device (CCD) chip output into an analog picture. While CCD cameras are often larger, they do tend to transmit a better image.
Light Level
Ambient light is important when picking a CCTV system. If the environment you are observing is dark, the lux specification becomes extremely important. The lower the lux number is, the better the camera is at recording in dark conditions. If you are only observing well-lit areas, lux is not an important specification. Specialized outdoor CCTV cameras will generally require a lux specification of 0.00003 to record on moonless nights. Most CCTV cameras are manufactured to a specification of .3 to .5 lux.
Resolution
Higher resolution cameras will present a sharper image than low resolution cameras Resolution is measured in lines. For example, a standard resolution television has a screen resolution of 480 lines, while high definition televisions (HDTV) have resolutions of 1,080 lines. Generally, most CCTV users don't need a HDTV resolution. Most CCTV cameras tend to resolve between 330 and 400 lines. Higher camera resolutions are available if additional picture detail is desired.
Digital Television Recorder vs. Videotape
What you are recording on is also an important specification. Some low-cost systems still output to a video cassette recorder. Using a VCR will require the changing and storage the physical tape. Use of a digital television recorder (DTV) will allow all of the surveillance to be saved on a computer hard drive. Using a DTV also makes scanning through the surveillance files much easier. All video footage can be viewed via a computer screen, and there is is no impact from lost or damaged videotape.
Tags: cameras often, cameras will, CCTV cameras, Closed circuit, CMOS camera, Color cameras, important specification