At present, the "HD" has become a video security surveillance industry, the most popular vocabulary, but there is no specific criteria. The majority of projects and users is only to determine whether high-resolution high-definition cameras. In fact, the resolution is the "HD" and a necessary condition but not sufficient condition for high resolution can only say is similar to the static "high-definition." So, the real "HD" quality, in addition to high-resolution, we should also examine what areas? In this paper, from the engineering application point of view, and focus on usability, analysis of what works in security monitoring purchase high-definition cameras.
1. High-definition video camera main application in the financial system, road traffic monitoring, and other special requirements on the image place. These places are the high demands on the image to look at facial features, the vehicle registration numbers. Therefore, if you undertake the project is a place for these applications, then you can choose from a cost up to consider whether the product.
2. To understand the product
At present, the market put more than 480 line camera positioned as high-definition cameras, in fact, sold on the market for more than 500 lines of high-definition cameras and 480 lines, some CCD is essentially the same, mainly video digital processing chip (DSP) in different . Some vendors have a strong R & D capability, they developed 15 ~ 16-bit (bit) of video digital processing chip, compared to the market 480TVL camera SONY 10-bit (bit) chips have more data-processing capacity and faster access to images processing speed.
3. Target detection
In fact, more than 500-line high-definition surveillance cameras and 480 lines of resolution, a single is difficult to distinguish from the naked eye out. Therefore, first of all to use professional testing equipment to test, test the camera's clarity, color reproduction degrees, SNR, illumination, synchronization, color sync, sub-carrier frequency and other technical indicators. Second, it can simulate a number of scenarios for testing. Was mainly observed a static definition, dynamic clarity, color reproduction degrees. You can shoot scenery, landscape, flowers, moving objects, people, observe the screen is clean, noise, size, color is natural and realistic.
4. Functional
High-definition surveillance cameras are mainly reflected in the clarity of the screen, it is necessary to achieve the clarity of the screen, not just to achieve a horizontal resolution of 540TVL on the line, and preferably also has a number of wide-dynamic, auto white balance, image sharpness adjustment, Super Digital Noise Reduction (SNR), intelligent digital automatic light compensation functions. Detection of wide dynamic functions, the need to observe the bright areas and dark areas is a clear transition between the natural, wide dynamic range is automatically adjusted. A good camera in the light and dark areas, there will be rich in depth and delicate performance of the big lamp at night to see license plates, the headlight contours of the filament and the plate are very clear, and there are no bright-line vertical. The illumination will have to at night to observe the surveillance camera images are clear, what the size of the noise.
5. The operation set
Operation to set the camera parameter settings, mainly from convenience to examine. The current operation of high-definition cameras mainly through the menu and set the dial to adjust the code in two ways. Zexu camera with menu menu-oriented feature is rich, is it easy to be fine, can meet the complexity of the different monitoring environment. Chinese menu to debug than the English menu, intuitive, easy to use. At present, some of the camera menu, with standard daytime, day and night, night KTV entertainment, custom mode, you only need to select a model can easily deal with complex environmental needs, fast and convenient.
6. Data interface
In practical applications, surveillance cameras may be due to environmental or human damage, leading to not work correctly. Therefore, to purchase high-definition cameras, we should also note that it is rich in data interfaces. Observe whether there is alarm on the rear panel interface, audio interface and RS-485 interface. Some interfaces can improve the level of security monitoring, some of the menu interface for easy call to set up a remote.
7. Power supply wide range
In practice, engineering, often encountered in the unstable power supply burned camera phenomenon. Particularly in some remote mountainous areas, the voltage high and sometimes low, very easily lead to surveillance cameras can not function properly. At present, most of the camera's power DC24V and AC12V. Some, however, the camera manufacturers have the power redundancy features, such as the standard voltage AC12V, but the camera was able to work between 9 ~ 16V. The advantage of a wide range of power supply voltage is unstable and naturally, when highlighted.
8. Installation and commissioning
High-definition cameras and regular cameras basically the same method of installation and debugging, but must pay attention to a good camera matching, because the poor quality of the lens, or the matching is not good, will largely affect the clarity of the screen. Such as lens size, and surveillance cameras have to be considered matches. There are, after the lens focal plane to align, protective front cover glass to adopt good quality optical glass, which will affect the clarity.
9. Accessory products
To obtain high-definition video, in addition to front-end is a high-definition camera, the transmission system, intermediate system and the terminal display system must meet the requirements of bandwidth and compression in order to achieve the practical effect of high-definition. Including cable, matrix, DVR, video server, all kinds of video encoder. Large bandwidth of fiber optic cable attenuation is small, high anti-interference, can be better guaranteed to send the image of the target. Terminal displays the best choice for progressive scan monitors, but also more than 600 lines. Therefore, the light use of high-definition video camera while neglecting other supporting equipment used is not up to the real purpose.
10. Technical support
Finally, prior to purchase, do not forget to learn about the vendors on products technical support, whether they can provide specialized technical training, special features and operation of the product to conduct a detailed explanation of the menu, which is for the construction, are is the most practical. In addition, a problem if the product does not work, the vendor is able to provide appropriate technical services, in the shortest possible time, to maintain and repair products, this point is very important.
The above knowledge is provided by SecurityCamera2000.com, any reproduction, please specify the source.
Source:www.SecurityCamera2000.com
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