The security technology system has experienced the development and changes from simple to complex, from decentralized to combination and integration. It has developed from the early single electronic anti-theft alarm system to the alarm system linked with video monitoring, and then to the comprehensive prevention system connected with visual access / entrance control, until community management and the integrated anti-theft and fire control, video monitoring, access / control Visitor inquiry, security patrol, parking lot and gas station management, intelligent transportation, electronic newspaper, financial services, electric power, petrochemical, military, public security and party and government departments, etc.) and system integrated information tickets, important units (such as security technology system for control and management, etc.). As we all know, a complete security system should have the following three basic elements. 1) Intrusion detection That is, various abnormal phenomena in the prevention area can be found in time. The objects detected by the security system are mainly people and their behavior. Illegal behavior is called intrusion, so the detection of security system is also called intrusion detection. The equipment to realize detection is alarm (detector). Infrared detection and microwave detection are the most commonly used detection technologies. The design of early detectors was very simple. For example, there was no difference between passive infrared detectors and infrared sensors for gating and water saving, so the false alarm rate was very high. Other alarms are the same, so the high false alarm rate has become a major problem perplexing the early security system. 2) Video surveillance The security system must be able to evaluate the detection results (judge their authenticity), control the development process of events and understand the results of event disposal. It 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 monitoring 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 and occupies a large proportion in the security system. At present, as long as there is security, there must be video surveillance, which has become a fixed pattern. 3) Perimeter management and access control Perimeter (edge) is a clear prevention area for the security system, that is, a closed perimeter is formed through various physical and technical means, and the access / entry of people and things is managed and controlled through the access / entry combined with the perimeter. The security system shall ensure the smooth access of people and objects legally entering and leaving the prevention area, and effectively detect and prevent illegal entry / exit. Obviously, access control is a common equipment for access control. High strength doors equipped with high security (anti-theft) locks are the oldest access control equipment. Electronic control and system using feature recognition technology are typical ways of modern access control. However, the constituent elements of the two are the same.