Common sense of surveillance cameras

The camera is a front-end device for acquiring images from the monitoring site. It uses an area array CCD image sensor as the core component, plus a 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 conference TV systems that do not require high image quality. Since the main indicators such as the resolution and low illumination of the MOS image sensor are temporarily inferior to the CCD image sensor, the camera used in the monitoring system is still a CCD camera.

The camera is divided into black and white and color. Because the black and white camera has the advantages of high resolution and low illumination, especially it can be imaged under infrared light, so in the television monitoring system, the black and white CCD camera still has a high market share. By the way, the cameras in the list of CCTV surveillance equipment listed are usually without lenses (except for integrated cameras), so in practical applications, the camera should be equipped according to the actual environment of the monitoring site and user requirements. The use of the lens camera is very simple, usually as long as the lens is properly 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 is adjusted, the expected use effect may not be achieved. It should be noted that the interface between the lens and the camera is a C-type interface or a CS-type interface (this point must be remembered, otherwise it is highly likely that the CCD chip of the camera will be damaged when the C-type lens is directly screwed into the CS interface camera).

When installing the lens, first remove the protective cover of the camera and the lens, and then gently screw the lens into the lens interface of the camera and make it in place. For the automatic iris lens, the control line of the lens should also be connected to the automatic iris interface of the camera. For the electric two-variable lens or three-variable lens, as long as the lens is rotated in place, there is no need to correct its balance state (only after Only after the coke adjustment is completed, it is necessary to finally correct 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 match the 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 when the application site is the brightest (the ambient light is the largest), the lens aperture should be opened as far as possible and the image is still optimal (the image should not be overly White and overload), the lens is adjusted. Install the protective cover and attach the bracket to the above adjustment process. If you do not pay attention to open the lens aperture as much as possible when the light is bright, but close it relatively small, the electronic shutter of the camera will automatically adjust to the low speed , So you can still form a better image on the monitor; but when the light is 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 It was dim.