Several technologies in the monitoring

Summary: monitoring principle - process - technology: video surveillance needs to be used in the three mainstream technologies outlined. The following content is organized by the understanding of the network. Provide you with reference. Several technologies in the application of monitoring

With the development of communications, computer, multimedia technology, and security, finance, education and other industries increasing customer demand, large-scale remote video surveillance system is rapidly building up across the country. Video surveillance in the analog monitoring, digital and analog combination of monitoring, all-digital monitoring of the development, is moving towards networked, platform, large-scale, integrated direction.

The traditional video surveillance technology has been unable to meet the new business needs and new business models. The development of video surveillance, more and more need for the synthesis of various technologies, and continuous innovation. The future video surveillance system will be a variety of advanced technology. The following is a brief description of the current video surveillance needs to be used in a variety of mainstream technologies.

One, streaming media technology

Real-time video surveillance and video playback is the video surveillance of the two important basic business, the essence of the video source of multimedia data transmission to the video receiver. Real-time video surveillance requires the completion of real-time transmission of video, with a strong real-time; video playback is similar to VOD business, with a certain degree of real-time (but not very strong), the requirements of the picture is clear and smooth, and can complete a variety of playback control operations.

We can see the front-end camera as a real-time A/V source, and the video file as a stored A/V file, then a good way to solve such problems is to use streaming media technology.

We know that streaming and streaming media (StreamingMedia) are developed to solve the problem of real-time information transmission. Streaming transmission mainly refers to the transmission of media through the network (such as audio, video, etc.) technology in general, the specific meaning of the network will be audio and video information transmitted to the user terminal playback, without waiting for all the files downloaded to play, but the continuous audio and video information compressed and placed on the server, the user terminal playback, as long as the beginning of the content of the part of the memory, the rest of the data stream from the user terminal in the background to continue to receive and play until the end of the playback. The rest of the data stream will be received and played by the user terminal in the background until the playback is completed or the user aborts the operation. In this way, the waiting time for the user to play the media will be significantly reduced and there is no need for a large cache. Streaming media refers to continuous time-based media using streaming technology.

Streaming is primarily proposed to distinguish it from download transfers. The traditional download transfer method has two basic conditions, one is file-based operation and the other is that the file has to be downloaded in its entirety before it can be used (played). For real-time video surveillance, there is no concept of file, so it can not be realized in the way of "download". For video services, video data can exist in the form of files, but if the video data must be completely downloaded before playback, it will bring a large delay, the user can not stand. Therefore, the more ideal way is to use streaming transmission.

There are two ways to realize streaming transmission: sequential streaming (ProgressiveStreaming) and real-time streaming (RealtimeStreaming). Video surveillance services mainly use real-time streaming.

The network camera can be regarded as a server that provides real-time A/V source, and when the user requests real-time monitoring, the network camera uses real-time streaming to transmit the monitoring screen to the user terminal. Considering that multiple users accessing the network camera at the same time will bring about traffic bottlenecks and other problems, a video server can be used for transit, allowing the video server to provide a strong load capacity.

The above is just a brief description of the principle. The above program can meet the small video surveillance system, but in the large video surveillance system, monitoring the number of front-end devices and user terminals are very large, in addition to increasing the consideration of multicast, broadcast and other programs, but also need a set of perfect media distribution, scheduling mechanism to ensure the efficient delivery of media. In this regard, there is no ready-made mature program, the China Communications Standards Association (CCSA) is actively studying this, in order to provide a standard media delivery mechanism for future video surveillance systems.

Two, Presence technology

Mention of Presence, the first thing that comes to mind is instant messaging (IM). The combination of Presence technology and video surveillance seems to be a relatively new reference. Thinking about it in a traditional way, it seems that the two don't have much to do with each other. In fact, Presence can serve video surveillance very well.

Presence, also known as "PresenceInformation," which is generally translated as "presentation," is used to convey a user's status and his or her ability to communicate through a set of devices. Presence is most commonly used in instant messaging tools, for example, in many IM programs there are states such as: online, busy, away, offline, etc. These are called "Presence". These are called "Presence states" and characterize the current state of the user. These states also reflect the ability of the user to communicate with other users, for example, if the user is "offline", other users cannot communicate with them using instant messaging.

One of the simplest Presence processes is as follows: a user (called a Watcher) subscribes (SUBSCRIBE) to the Presence state of another user (Presentity) in which he is interested, and Presentity accepts the subscription request. Presentity accepts the subscription request. After the state of Presentity changes, he will publish his new state, which will be notified to the Watcher.

From the system's point of view, there are many similarities between the front-end devices of video surveillance and the users of the IM system. devices: (1) whether they are logged into the system; (2) what capability sets they have (e.g., what encoding methods they support, whether they support encryption, whether they support remote PTZ control); and (3) whether they are being accessed by a user, and by what users, etc.

It's easy to see that the maintenance of these "states" is where Presence technology excels. It is clear that if Presence technology can be applied to video surveillance systems, it will bring great convenience.

Three, intelligent video technology

Intelligent video surveillance is one of the most cutting-edge applications in the field of networked video surveillance.

Intelligent video (IV, IntelligentVideo) from computer vision (CV, ComputerVision) technology. Computer vision technology is one of the branches of artificial intelligence (AI, ArtificialIntelligent) research, which can establish mapping relationships between images and image descriptions, so that computation can understand the content of the video screen through digital image processing and analysis.

Intelligent video technology as referred to in video surveillance mainly means, "the automatic analysis and extraction of key information from a video source." If you think of a camera as a human eye, an intelligent video system or device can be thought of as a human brain.

The purpose of building a video surveillance system is, first, to visually extend -- to "bring" the image of a place elsewhere to the eye through the network and equipment, so there is a remote monitoring; and second, to intellectually extend --Let the system automatically analyze and solve problems for us, so there is intelligent monitoring. Of course, the latter is a higher level of requirements, but also the inevitable requirements of the future development of video surveillance.

Traditional video surveillance systems lack intelligence and rely heavily on human judgment. However, human beings have their own insurmountable weaknesses, such as: (1) limited manpower, human reaction and processing speed is limited, resulting in a limited number of locations that we can monitor in a given time. This means that not all monitored points are under surveillance at all times. (2) The human being is not a completely trustworthy observer. Whether watching real-time video streams or watching video playback, we are often unable to detect security threats due to our own physiological weaknesses, leading to underreporting.