To be a good webcam you have to know these things
Network security cameras has been popular, but a lot of people still don't know webcam working principle and main parts of functions, select a camera is a hindrance, good and evil people mixed up market cameras, because many people do not understand the technical parameters and performance of yesterday. Today, shenzhen kungfu security co., LTD will tell you the main parts, parameters and importance of webcam.
A, lens,
The lens is very important in the video acquisition, the quality of the lens will naturally affect the effect of video, although there are many kinds of lens, a great influence on video effect, the price of the lens from a few yuan to tens of thousands of yuan. However, in the monitoring field, it is not enough to buy tens of thousands of yuan of lenses, so the lenses on the basic market are similar. But the focal length of the lens for video effect significantly, whether this means that you should consider when you choose products choose replaceable lens model, or considering whether to choose a zoom lens. I have to mention here that zoom means that the focal length of the lens can be changed. Some network cameras with the function of digital variable times, digital variable times mean video image can be amplified, doesn't change the sharpness of the image, the application of network cameras of little value. Be especially wary of unprofessional salespeople or JS changing concepts.
Image sensor
This is the key factor that affects the video effect. At present, there are two kinds of CMOS and CCD in the market. In terms of imaging, the imaging transparency and sharpness of CCD are very good under the same pixel, and color reduction and exposure can ensure basic accuracy. And ordinary CMOS products tend to appear a gender, color reduction of physical ability weak (monitored object itself is tonal and monitor to see large difference, or even completely change color), exposure is not so good, because of its physical properties, ordinary CMOS image quality and CCD still has certain gap. CMOS video image artistic effect is better, just like people as fine art, as we all know, xinmi city is very beautiful but not very realistic, people usually puzzled by its artistic effect and ignore the importance of clarity and fidelity, when in fact surveillance industry both is very important.
Video compression algorithm (also called video compression format)
This is the most important factor in webcams because it directly determines video clarity, video fluidity, and video storage space. However, as I have known for many years, this most important factor is always avoided by the seller intentionally or unintentionally. The reason may be that the seller himself cannot tell the truth, or he has the motive of subjugation. But as a savvy buyer you must understand. At present, there are mainly h. 264 and MPEG4 video compression algorithms for network cameras in the market. The former is more compressible, and video has less loss, so it is clearer and smoother. The former can support a frame rate of 25 frames per second, while the latter generally does not exceed 10 frames per second. This means the latter's video is not coherent and real-time; Because the compression rate of MPEG4 is not enough, if you do full real-time, the code flow is too large, the remote will be hard to get.
4. Image format
Image format is to decide the actual video image pixels, DVD format and VGA (640 * 480) format and CIF format (352 * 288) two, DVD image formats family contains D1, D2 (720 * 576 interlaced scanning) (1048 * 720), D3, D4 (1920 * 1080 interlaced scanning) (1280 * 1280 progressive scan) and D5 (1920 * 1080 progressive scan) five kinds of image formats, the current mainstream on the market for D1. Support for D3 and D4 megapixels are listed, just because of its bandwidth is more, It's not widely used.
Different format pixels and video file sizes are different. Without the same image format, we cannot determine the merits of a webcam just by the size of the hard disk needed for the video. A network camera image formats tend to adjust, this means that if your hard disk space is not big enough, but need to record a long time, can be used to reduce image formats.
Five, the frame rate
As is known to all, any video file is composed of continuous images, an image we call it as a frame, like a second video is composed of 25 Zhang Lianxu images, then the frame rate is 25 frames per second. In PAL mode, video of 25 frames per second can be very vivid. If it is less than 25 frames, the action in video will not be coherent enough, and the lower it is, the less coherent it will be, and even the jump action will appear. So frame rate is very important in video monitoring. This parameter will be displayed on the interface of video monitor. This parameter is also ignored by many unprofessional salespeople. You must pay attention to this when you buy a product, because there is a big difference in the cost of a 25 frame/second webcam.
Vi. Dual code flow
Some webcams are designed to support two video signals, known as a binary stream. The benefits of the double stream is viewed, code all the way along the stream flow than to watch and storage are used along the stream can more effectively prevent the network congestion, so as to better safeguard video on effective network bandwidth of fluency.
7. Front-end storage
Some webcams have an SD card slot or a USB mobile storage interface, which we call front-end storage. Front-end storage is often used in monitoring environments where bandwidth is not sufficient. Some environments are not convenient to install broadband, and use the function of front-end storage to save the monitoring video so as to achieve a certain monitoring effect.
Viii. Product line
In most large monitoring systems, multiple types of products are often used, because video management software of various manufacturers is difficult to be compatible with other brands of network cameras. Therefore, when selecting a brand for the monitoring system, it is necessary to consider whether the brand has a rich product line to meet the demands of various environments and system solutions. The support such as infrared, support WIFI, POE, support optical fiber access, if there is a video server supports braket, zoom, so that can be combined with some special analog cameras and video decoder can be connected to the TV wall, etc.
Software functions
Most monitoring systems require centralized management, so whether video management software is powerful and the interface is friendly is also a question that must be considered in product selection. The function of management software module is more, so the performance of video management software identified needs comprehensive consideration, a function cannot be overstated, also cannot ignore a certain function, to the actual requirement.
In addition to the above nine functions, infrared night vision capability, ultra-low illumination, wide dynamic performance and strong light suppression are also some important parameters of network cameras. To sum up, the selection of network camera requires certain professional knowledge and patience. Choose the right one instead of the expensive one. We hope you can choose your own suitable network camera.