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Surveillance Definitions AGC - Automatic Gain Control is an electronic circuit that keeps the video signal at a constant level (1volt peak-peak). Useful on cameras working at low light levels AI - Auto Iris is an automatic method of varying the size of a lens opening in response to changesin scene illumination. AWB - Auto White Balance is an electronic process used in video cameras to retain true colors.It is performed electronically on the basis of a white object in the picture. CCD - Charged Coupled Device: It is analog technology. The CCD camera has a little bit higherresolution than CMOS. The camera also functions better in low light. A CCD camera drains a little bit more power than the CMOS cameras. It uses 12v instead of 9v. CMOS - Complementary Metal Oxide Semiconductor: a lower resolution camera compared to a CCD model.The advantage of a CMOS camera is that it uses lower operation current. CMOS camera is smaller than a CCD camera and works longer with the 9v battery. HAD CCD - Hole Accumulation Diode is a type of CCD sensor with a layer designed to accumulateholes (in the electronic sense), thus reducing noise level. S to N Ratio - Signal to Noise Ratio is simply the ratio of the signal power and noise power,expressed in decibels (dB). Or measure of noise on a video signal. It is represented in Decibels as the level of the video signal compared to the level of noise present on that signal. The higher the signal to noise ratio the better. BLC - Balance Light Control is a method to compensate for bright spots in a picture. It is alsoimportant to consider whether there are bright spots in the picture such as car headlights which can make identification of the vehicle registration or model impossible. This can also be a major problem where it is necessary to identify a person who is moving from bright daylight into artificial light. This could result in the subject becoming an unidentifiable silhouette. OSD - On Screen Display is a method of displaying set-up information or instructions on to adisplay monitor. Resolution - Resolution measures the cameras ability to reproduce an image. The higher theresolution, the better the picture quality. LUX - LUX is the measurement of low light needed for the camera to view and record properly. FPS - Frames Per Second is the number of still frames (pictures) that give the illusion of motion,which appear in a single second of time.30fps is considered "real time". So for real time viewing of your cameras, you need at least 30 fps for each camera. IR - Infrared, IR LEDS are used on Day/Night cameras which allow the camera to see in the dark. Focal Length - the distance from the surface of a lens to its focal point. |
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