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The key technology in the application of hd ip camera

   HD ip camera addition must pay attention to the front-end installation and selection, but also must have a transmission system, the actual effect of the intermediate and terminal system used in conjunction with the display system in order to achieve high resolution. Transmission system, the transmission of video images will generally choose coaxial cable, twisted pair UTP line (network transmission), radio transmission, cable transmission, regardless of the manner in which transfer the image from the front-end transmission access bandwidth to each ring in the back-end of the entire system greater than 6M, so as to ensure the image to achieve the requirements of high-definition, and comply with the requirements on the detection of Engineering and Technical Security. Coaxial cable over 150 meters or 200 meters, in the general case the image quality will be decreased significantly, which is due to the various measures must be taken to ensure that its terminal bandwidth not less than 6M, if necessary, through the coaxial cable's characteristics, increase video compensation amplifiers. Is not the role of the video amplifier, the compensation of the indicators should ensure that the high-frequency compensation amount, the amplitude-frequency characteristics, signal-to-noise ratio, common-mode rejection ratio, differential phase distortion, chroma luma delay, width chroma gain and so reach The related cable loss or attenuation caused by the defect to be compensated, in order to ensure a high-definition image into the system.
   Currently, due to rising copper prices, the cost of fiber optic transmission of the video image declining, the transmission of the longer distances or multiple images using optical fiber transmission has been widely used as a fully staffed program. Because of the large bandwidth of the fiber optic cable, attenuation, high anti-interference, small size, strong confidentiality, indicators of image transfer can be better guaranteed. When using other means to transmit images, you must also ensure that the bandwidth of the channel. High definition image must also rely on good terminal display equipment performance, so it is best to choose a progressive scan monitor. Because in the actual use interlaced monitor image flicker serious people are likely to produce visual fatigue. If the low-resolution monitor the same amounted to less than the overall clarity of the requirements. Because by the monitor when the monitor's sharpness, the bandwidth of the video channel and CRT dot pitch, the distance determined. According to information available, the translation between the theoretical upper limit in the channel bandwidth and clarity 1M/80 line further consider high-definition video signal amplitude factor was to reach the monitor display 400 lines of video image clarity indicators should be adopted by the experience of more than 600 lines of the machine. In line with the use of hd ip camera, the intermediate processing equipment, including matrix, DVR, video server, various video encoder and so must meet the requirements of bandwidth and image compression, to make high-definition network camera to give full play to its inherent role alone use the optional HD ip camera and to neglect other ancillary equipment is not up to the real purpose.
   Nominal horizontal resolution of high-definition ip cameras currently on the market, 500 lines, 520 lines, 530 lines, 540 lines, 550 lines, and the number of species. In fact, there 480TVL and 540TVL of the CCD of the camera is basically the same, the main video digital processing chip (DSP). Some manufacturers have a strong R & D capabilities, they developed a 15/16 (bits) digital video processing chip, enhanced data processing capabilities and faster image processing than 480TVL camera on the market 10 (bits) chip speed. The chip uses a 15/16-bit data bus, built-in sophisticated logic processing circuit and pixel enhancement units, has a powerful fast and accurate image processing capabilities, fully compatible with various CCD on the market, you can reach the ordinary high-definition CCD image capture 540TLV above high-definition, but also has the computing power of the ultra-high-speed data, and can carry a wide white balance compensation range and zero color rolling. The more popular these network cameras can guarantee to pass over 540TVL horizontal resolution color image, of course, more than 10 (bits) chip 480TVL camera market.
   HD ip camera is mainly reflected in the clarity of the screen to achieve the clarity of the screen, not just a horizontal resolution of 540TVL on the line, wide dynamic, automatic white balance, image sharpness adjustment, super digital noise reduction (SNR), intelligent digital automatic metering compensation, the luminance signal and the color signal edge correction, automatic adjustment and recovery of damaged pixel, color adjustment, wide dynamic range indicator epitomizes. Only these comprehensive requirements to be considered a high-definition network camera. Single on the terms of the resolution, 540TVL course better than 520TVL and 480TVL effect, higher-end HD ip camera must be dealt with the problem of gamma correction, gamma correction is an important technology to produce high-quality images According to related statistics, the majority of CRT tube only 1/0.45 = 2.22 gamma curve, LCD gamma curve only 1/0.3 = 3.33, we can see that a high-quality linear video signal to the CRT to display, because 80% of the lumens compressed into only 30% of the gray scale and the rest of the poor image blurred and dark scene, and the human eye can see is completely different. In order to overcome this natural physical characteristics of the CRT tube, monitoring the video must be sent to a CRT before gamma correction, must be amplified in the dark areas of the bottom line of the gamma curve to 0.45, while the 2.22x0.45 = 1, and only then can the CRT screen made a 1:1 image. Thus, in the gamma correction process, the digital signal processor must be provided is greater than 2.22 times the above information. Preferably gamma correction method is the use of 12-bit digital signal processor, 8 4 of the digital signal processing, as a correction, to produce a perfect image. Of course, the 15/16 of the chip will be more excellent, the conventional network camera using only the 10 digital signal processing chips, can only provide a 12-bit correction, results in dark areas of the image will be lost part of the gray scale and color conversion information, so the DSP chip One of the important indicators of processing capacity and the number of bits is our choice and to identify high-definition network camera.
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