Surveillance camera is the front-end equipment for acquiring surveillance scene images. It uses area array CCD image sensor as the core component, plus synchronization signal generation circuit, video signal processing circuit and power supply.
In recent years, new low-cost MOS image sensors have developed rapidly, and cameras based on MOS image sensors have begun to be used in videophone or video conferencing systems that do not require high image quality. Since the resolution and low illumination of MOS image sensors are not as good as CCD image sensors until the main indicators, the cameras used in surveillance systems are still CCD cameras.
Cameras are divided into black and white and color. Because black and white cameras have the advantages of high resolution and low illumination, especially they can image under infrared light. Therefore, in TV monitoring systems, black and white CCD cameras still have a relatively high market share. By the way, the cameras in the list of CCTV surveillance equipment listed are usually without lenses (except integrated cameras). Therefore, in actual applications, the cameras should be equipped with appropriate cameras according to the actual environment of the surveillance site and user requirements. The use of the lens camera is very simple, usually as long as the lens is correctly installed, the signal cable is connected, and the power is turned on to work. However, in actual use, if the lens cannot be installed correctly and the state of the camera and lens can be adjusted, the expected use effect may not be achieved. It should be noted whether the interface between the lens and the camera is a C-type interface or a CS-type interface.
When installing the surveillance camera lens, first remove the camera and the protective cover of the lens, and then gently screw the lens into the lens interface of the camera and make it in place. For automatic iris lenses, the control line of the lens should also be connected to the automatic iris interface of the camera. For a motorized two-variable lens or three-variable lens, as long as the lens is rotated in place, there is no need to correct its balance temporarily (only in the rear After the focus adjustment is completed, it is necessary to finally calibrate its balance state).
Adjust the lens aperture and focus. Turn off the electronic shutter and backlight compensation switches on the camera, aim the camera at the scene to be monitored, and adjust the lens aperture and focus ring to optimize the image on the monitor. If the camera is used in a situation where the illuminance changes greatly, it is best to connect an auto iris lens and set the camera's electronic shutter switch to OFF. If manual iris is selected, the electronic shutter switch of the camera should be set to ON, and the lens iris should be opened as wide as possible when the application site is the brightest (the ambient light is the largest) and the image is still the best (not to make the image too light). White and overload), the lens is adjusted. Install the protective cover and mount the bracket. During the above adjustment process, if you do not pay attention to opening the lens aperture as wide as possible when the light is bright, but closing it as small as possible, the camera's electronic shutter will automatically be adjusted to a low speed , So it can still form a better image on the monitor; but when the light becomes dark, because the lens aperture is relatively small, and the electronic shutter is already at the slowest (1/50s), the imaging at this time may be Dim
