The effects of network cameras are affected by many factors. The use of cameras in the market is already very extensive, but network cameras have become one of the most popular cameras. So what is it affected by?
What factors affect the performance of the network camera
First, the lens
The lens is the first hurdle of video collection. The quality of the lens naturally affects the effect of the video. Although there are many types of lenses, the effect on the video is greatly affected. The price of the lens ranges from tens of yuan to tens of thousands of yuan. But in the field of surveillance, it is not enough to buy a lens of tens of thousands of yuan, so basically the lenses on the market are similar. However, the effect of the focal length of the lens on the video effect is worth noting, which means that when you choose a product, you should consider whether to choose an interchangeable lens model or consider whether to choose a zoom lens. Speaking of which, I have to mention that zoom means that the focal length of the lens can be changed. Some network cameras have the function of digital zoom. Digital zoom means that you can enlarge the video image to see it without changing the sharpness of the image. It is of little value to the application of the network camera. Especially beware of some unprofessional salespeople or JS stealing concepts.
Image sensor
This is a key factor affecting the video effect. At present, there are two types of CMOS and CCD on the market. In terms of imaging, the CCD's imaging permeability and sharpness are very good under the same pixels. Color reproduction and exposure can be guaranteed to be basically accurate. However, ordinary CMOS products are usually of low permeability and weak color reproduction ability (the difference between the hue of the monitored object and that seen on the monitor is large, or even completely discolored), and the exposure is not very good. Due to its own physical characteristics, there is still a certain gap between the imaging quality of ordinary CMOS and CCD. CMOS video images have better artistic effects. Just like people take artistic photos, everyone knows that artistic photos are beautiful but not very realistic. People are often confused by their artistic effects and ignore the importance of clarity and fidelity. In fact, these two points are very important when monitoring the industry.
Third, the video compression algorithm (also called video compression format).
This is the most important key factor in the network camera, because it directly determines the video clarity, video fluency and video storage space. However, after many years of understanding, this most important factor is always avoided by the seller intentionally or unintentionally. The reason may be that it can't tell the truth or has a good motivation. But as a savvy buyer, you must understand it clearly. At present, the network cameras on the market mainly include H.264 and MPEG4 video compression algorithms. The former has more compression and less video 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 that the latter video is not consistent and not real-time; because the MPEG4 compression rate is not enough, if you do full real-time, the code stream is too large, and it is difficult to see it remotely.
Fourth, the image format
The image format determines the actual pixels of the video image. There are two formats: DVD format, VGA (640 * 480) format, and CIF (352 * 288) format. The DVD image format family includes D1 (720 * 576 interlaced), D2 ( 1048 * 720), D3 (1920 * 1080 interlaced scanning), D4 (1280 * 720 progressive scanning) and D5 (1920 * 1080 progressive scanning) five image formats, currently the mainstream on the market is D1. Support D3 and D4's megapixels are also on the market, but they are not widely used because they occupy a lot of bandwidth.
Different image formats have different pixels, and the video file size is also different. If it's not the same image format, we can't determine the pros and cons of a network camera based on the size of the hard disk required for recording. The image format of a network camera is often adjustable, which means that if your hard disk space is not enough, but you need to record for a long time, you can achieve it by reducing the image format.
Five, frame rate
As we all know, any video file is composed of continuous pictures. We call it a frame for a picture. For example, a one-second video is composed of 25 consecutive pictures. At this time, the frame rate is 25 frames / second. Under the PAL system, 25 frames per second of video can express motion very realistically. If it is lower than 25 frames, the motion in the video will be insufficiently coherent. So the frame rate is very important in video surveillance. This parameter will be displayed on the video monitoring interface. This parameter is also avoided by many unprofessional salesmen. Everyone must pay attention to this when purchasing products, because the cost of network cameras that support 25 frames per second varies greatly.
Six, dual stream
Some network cameras are designed to support two video signals, the so-called dual stream. The advantage of dual-stream is that using one stream to watch and one stream to store can prevent network congestion more effectively than watching and storing one stream, so as to better ensure the smoothness of video on effective network bandwidth.
Seven, front-end storage
Some network cameras have SD card slots or USB mobile storage interfaces, which we call front-end storage. Front-end storage is often used in surveillance environments where bandwidth is not sufficient. In some environments, it is inconvenient to install broadband, and use the front-end storage function to save the monitored video to achieve a certain monitoring effect.
Product line
In most larger surveillance systems, multiple models of products are often used, because the video management software of various manufacturers is currently difficult to be compatible with other brands of network cameras. Therefore, when choosing a brand for a monitoring system, it must be considered whether the brand has a rich product line to meet the needs of various environments and the system's ability to solve. Such as support infrared, support WIFI wireless, support POE, support fiber access, support PTZ, support zoom, whether there is a video server so that it can be combined with some special analog cameras, and whether there is a video decoder can be connected to the TV wall.
Nine, software functions
Most surveillance systems require centralized management, so whether the video management software is powerful and the interface is friendly is also a question that must be considered when selecting a product. There are many functional modules in management software. Therefore, the identification of the advantages and disadvantages of video management software requires comprehensive consideration. It is not possible to exaggerate a certain function or ignore a certain function. It must be based on actual needs.
In addition to the above nine features, infrared night vision capabilities, ultra-low illumination, wide dynamics, strong light suppression and other functions are also some important parameters of network cameras. In summary, the selection of network cameras requires certain expertise and patience. If you do n’t choose expensive, just choose the right one. Hope everyone can choose their own suitable IP camera.
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