HOW TO CHOOSING SURVEILLANCE CAMERAS

In this Topic we discuss the surveillance cameras that are part of the CCTV system.

CCTV cameras consist of Charge Coupled Device (CCD). CCD change the image that comes through the camera lens into electronic impulses. This device provides a good combination of low price and image quality for security applications.

The format of the camera is measured in inches: that is the most surveillance cameras fall between 1 / 4 "and 1". depending on the size of images that can be used are made in the camera. To use the most security, the small size of the fine - 1 / 4 "or 1 / 3" cameras dominate CCTV sales. Larger format do not always produce a better picture, but it can be advantageous in dimly lit situations since they are able to gather more light.

Many newer surveillance camera using digital signal processing (DSP) to convert analog video streams into digital information, improving image quality and to add functionality. The series of DSP in the camera can have a huge effect on picture quality.

Color vs. black and white

Let us compare with black and white cameras, these cameras can operate better than in very low light situations, most small and medium-sized businesses use CCTV in the neighborhood in a bright room. so in pity Some vendors do not even sell black and white camera again.

Resolution refers to how detailed a picture the camera can see. Measurements should look for is the horizontal line TV (TVL). A surveillance camera image normal is around 350-400 TVL, high resolution to get to 480 or 500. Upgrade resolution camera can cost as little as $ 50.

You also need to consider the entire system, to support the resolution. If your VCR records 350 lines and display monitor 400, the money you spent to upgrade to a camera with 500 lines is really wasted. In the end, a small fee to upgrade your camera can be multiplied by the cost to upgrade other equipment.

Signal to noise (s / n) indicates how much "signal," or actual picture information, transmits camera, as opposed to "noise," which appear as static. A s / n ratio of 40dB indicates that the signal is 100 times the noise, which produces images that can be accepted with some fine grain or snow. 30dB results in poor image, and 60dB produces excellent pictures without seeming static. Keep in mind that the noise can be introduced by other components in addition to the camera.