Characteristics and technical analysis of the hott

The development of video surveillance needs more and more technical integration and continuous innovation. Now let's talk about the characteristics of current video surveillance and various mainstream technologies that need to be used to reduce the dosage of toughening agent Poe; Art

video surveillance features

security technology is an application technology, which brings the technology of other disciplines to achieve its own security purpose. In this sense, security technology covers a wide range of fields. As long as it can be used to achieve security, it may be regarded as security technology. The early security system is like this, using all kinds of technologies and equipment to form a security system. As we all know, a complete security system should have the following three basic elements:

1 Detect and timely discover various abnormal phenomena in the prevention area. The objects detected by the security system are mainly people or human behaviors. Illegal behavior is called intrusion, so the detection of security system is also called intrusion detection. The equipment to realize detection is alarm (detector), and infrared detection and microwave detection are the most commonly used detection technologies. The design of early detectors is very simple, such as passive infrared detectors, which are no different from the infrared sensors used for door control and water saving. Therefore, the false alarm rate is very high. The same is true of some other alarms, so the high false alarm rate has become a major problem perplexing the early security system

2. The environmental monitoring and security system must be able to evaluate the detection results (judge their authenticity), control the process of the event and understand the results of the event disposal, and must have monitoring means. In the early security system, it is more to monitor with sound, and the cost is relatively low. With the maturity and popularization of television technology, image monitoring has become the main means. Due to the large amount of image information, good real-time performance, and the ability of active detection, it has gradually become the core technology of the security system, accounting for a large proportion in the security system. Nowadays, there must be video surveillance for security

3. The perimeter management, access control and security system should have a clear prevention area, that is, the perimeter (border). Through various physical and technical (Electronic) means, a closed perimeter is formed, and the access of people and things is managed and controlled through the entrance and exit combined with the perimeter. The security system should ensure the smoothness of people and objects entering and leaving the prevention area legally, and effectively detect and prevent illegal entry and exit. Obviously, access control is a common equipment suitable for access control. High strength doors with high security (anti-theft) locks are the oldest access control equipment. Electronic control and systems using feature recognition technology are typical ways of modern access control, but the constituent elements of the two are the same

presence technology

when it comes to presence, the first thing you think of must be instant messaging (IM). The combination of presence technology and video surveillance seems to be a relatively new formulation. Thinking in the traditional way, it seems that the two have nothing to do with each other. In fact, presence can serve video surveillance well

presence, also known as "presenceinformation", is generally translated into "presentation" in Chinese to convey the user's status and the user's ability to communicate through a group of devices. Presence is most commonly used in instant messaging tools. For example, in many IM software, there are online, busy, left, displayed offline and other states. These are called "presence states", which represent the current state of the user. At the same time, these states also reflect the ability to communicate with the user and other users. For example, if the user is in the "offline" state, other users cannot communicate with it with instant messages

the simplest presence process is as follows: a user (called watcher) subscribes to the presence status of another user (presence) he is interested in, and presence accepts the subscription request. After the state of presentity changes in the future, he will publish his new state, which will be notified to watcher. The following figure shows the presence model proposed by rfc2778

rfc2778presence model

from the perspective of the system, each monitoring front-end device in the video monitoring has many similarities with the users in the IM system. For example, the system should always know each monitoring front-end device: (1) whether it has logged into the system; (2) What kind of capability set does it have (such as which coding method is supported, whether encryption is supported, and whether remote PTZ control is supported); (3) Whether it is being accessed by users, and which users are accessing it, etc

it is not difficult to find that the maintenance of these "states" is what presence technology is good at. It can be seen that if the technological achievements of presence can be applied to the video monitoring system, it will bring great convenience

intelligent video technology

intelligent video surveillance is one of the most cutting-edge application modes in the field of networked video surveillance

intelligent video (IV) is derived from computer vision (CV) technology. Computer vision technology is one of the branches of artificial intelligence (AI). It can establish a mapping relationship between image and image description, so that computing can understand the content of video through digital image processing and analysis

the intelligent video technology mentioned in video surveillance mainly refers to "automatic analysis and extraction of key information from video sources." If the camera is regarded as human eyes, the intelligent video system or device can be regarded as human brain

the purpose and scope of application of the film pendulum impact testing machine in the construction of the video monitoring system: first, the purpose of the system is to extend the vision - to "bring" the pictures in other places to the eyes through the network and equipment, so it has remote monitoring with a variety of medalist formulas provided by teknor apex; Second, for the extension of intelligence - let the system automatically analyze and solve problems for us, so there is intelligent monitoring. Of course, the latter is a higher-level requirement, but it is also an inevitable requirement for the future development of video surveillance

traditional video surveillance systems lack intelligence and rely on human judgment to a large extent. However, human beings have their own insurmountable weaknesses, such as: (1) limited manpower, limited human response and processing speed, resulting in limited locations where we can monitor within a specified time. This means that each monitored point is not monitored all the time. (2) People are not completely reliable observers. Whether watching real-time video streams or watching video playback, we often fail to detect security threats due to our own physiological weaknesses, resulting in the occurrence of underreporting

streaming media technology

real time video surveillance and video playback are two important basic services of video surveillance. Their essence is to transmit multimedia data on the video source to the video receiver. Real time video monitoring requires real-time transmission of video, which has strong real-time performance; Video playback is similar to VOD business, which has certain real-time (but not very strong), requires clear and smooth pictures, and can complete various playback control operations

we can regard the front-end camera as a real-time a/v source and the video file as a stored a/v file. At present, a good way to solve this problem is to use streaming media technology

we know that streaming transmission and streaming media are developed to solve the problem of real-time information transmission. Streaming transmission mainly refers to the technology of transmitting media (such as audio, video, etc.) through the network. Its specific meaning is that when audio and video information is transmitted to the user terminal through the network, it can be played without waiting for all files to be downloaded. Instead, continuous audio and video information is compressed and placed on the server. When the user terminal plays, as long as the beginning part of the content is stored in its memory, Other data streams are 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 users to play media will be significantly reduced, and there is no need to cache too much. Streaming media refers to continuous time-based media using streaming transmission technology

streaming transmission is mainly proposed to distinguish from download transmission. The traditional download transfer method has two basic conditions, one is based on file operation, and the other is that the files can only be used (played) after all the files are downloaded. For real-time video monitoring, there is no concept of file, so it cannot be realized by "downloading". For the video recording business, the video data can exist in the form of files. However, if the video data cannot be played until it is completely downloaded, it will bring a lot of time delay, which users can't bear. Therefore, the ideal way is to use streaming transmission

there are two methods to realize streaming: progressivestreaming and realtimestreaming. Video monitoring business mainly adopts real-time streaming transmission

schematic diagram of video monitoring using streaming media technology

the above figure is the schematic diagram of the architecture of video monitoring system using streaming media technology. The network camera can be regarded as a server providing real-time a/v source. When the user requests real-time monitoring, the network camera uses real-time streaming transmission to transmit the monitoring image to the user terminal. Considering that multiple users accessing the webcam at the same time will bring traffic bottlenecks and other problems, we can use the video server to transit, so that the video server can provide strong load capacity

the above is only a brief description of the principle. The above scheme can meet the needs of small-scale video monitoring systems, but in large-scale video monitoring systems, the number of monitoring front-end devices and user terminals is very large. In addition to considering multicast, broadcasting and other schemes, a perfect media distribution and scheduling mechanism is needed to ensure the efficient transmission of media. In this regard, there is no ready-made mature scheme at present. China Communications Standardization Organization (CCSA) is actively studying this to meet the needs of social products and environmental protection, so as to provide a standard media transmission mechanism for the future video surveillance system. (end)