Business: infrared camera HD camera dome camera
In the general security monitoring system installation, the installation and debugging methods of HD cameras and ordinary cameras are basically the same, but we must pay attention to the lens matching, because the quality of the lens is not good, or the matching is not good, will greatly affect To the clarity of the picture, for example, infrared night vision system camera is best to use infrared lens, and 1/3 inch CCD is generally equipped with 1/3 inch lens, 1/2 inch CCD is generally equipped with 1/2 inch lens, install The focus adjustment of the lens must be adjusted during debugging, especially the rear focal plane of the camera must be adjusted. In many cases, the unclear focus of the lens will cause the image to be blurred, and the high definition requirements cannot be achieved. In addition, the camera's protective cover can not be ignored, the front end of the gun-type protective cover glass can not use the general flat glass, but must use better optical glass, the general flat glass of the image of the analytical power of a very powerful weakening effect, use The spherical shell should pay attention to the fact that the curvature of the spherical surface must be smooth and smooth. It is better not to align the lens with the upper edge of the spherical shell, where the refractive power of the light is large, and even the sharpness of the image is seriously affected. It is important to note that no matter what type of housing, the light in the housing should be as low as possible, and the distance from the lens to the housing should be as short as possible. This can minimize the light pollution in front of the lens and improve the image. The clarity.
HD surveillance camera system must be HD
In addition to high-definition cameras must pay attention to the front-end installation and selection, but also must have the transmission system, the middle system and the terminal display system can be used in conjunction with the actual effect of high-definition.
For high-definition surveillance camera systems, the transmission of video images will generally choose the coaxial cable, twisted pair, UTP line (ie, network transmission), wireless transmission, optical cable transmission, etc. No matter which method is adopted, the image must be The bandwidth of each ring in the entire system transmitted from the front-end to the back-end is> 6M, so as to ensure that the image meets the requirements of high-definition and meets the engineering and technical inspection requirements. Under normal circumstances, when the coaxial cable exceeds 150 meters or 200 meters, the image quality will obviously drop. This is due to the characteristics of the coaxial cable itself. Therefore, various measures must be taken to ensure that the terminal bandwidth is not less than 6M. Video compensation amplifiers to solve, the role of the general video amplifier is not. The compensation index should ensure that the high-frequency compensation, amplitude-frequency characteristics, signal-to-noise ratio, common-mode rejection ratio, differential phase distortion, chroma brightness delay, and chroma width gain all make the relevant cable loss or attenuation. The defects are compensated to ensure the high definition of the images entering the system.
At present, as the price of copper cables continues to rise, the cost of transmitting video images using optical cables has been declining. In long distances or multiple image transmissions, the use of optical cables to transmit multiple transmissions is widely adopted. Due to the characteristics of large bandwidth, low attenuation, high anti-jamming, small size, and strong confidentiality of the optical cable, various indicators of image transmission can be better guaranteed. When using other methods to transmit images, the bandwidth of the channel must also be guaranteed.
High-definition images must also rely on a good terminal display device to present in front of human vision, so it is best to choose a progressive scan monitor. Because the image of the interlaced monitor flickers in actual use, it is easy to cause visual fatigue. If the clarity of the monitor is low, then the overall clarity requirements are also not achieved. Because the definition of the monitor is determined by the bandwidth of the monitor, the video channel, and the pitch and distance of the picture tube. According to the data, the theoretical upper limit of conversion between the channel bandwidth and the resolution is about 1M/80 lines. If the factor of the amplitude reduction of the video signal at high definition is taken into account, the display of the 400 lines of video images should be clear. The degree indicator should be based on experience using more than 600 lines of machinery. In order to make the HD camera system work properly, intermediate processing equipment, including matrix, hard disk recorders, video servers, various video encoders, and so on, must meet the requirements of bandwidth and image compression in order to make the high-definition camera fully play its intrinsic role. effect. The use of high-definition cameras and the neglect of the selection of other ancillary equipment is not a real goal.
With the rapid development of the industry, the demand of users is getting higher and higher, and the performance and parameters of high-definition cameras will also be high in the months to come, and the requirements for the entire monitoring system will also be more stringent.
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