With the progress of technology, video surveillance system has been widely used in various fields of national public security prevention, which makes people's security environment improved to a great extent. The present video surveillance system mainly adopts the combination of visible light camera, manual surveillance and video recording for daily security protection. However, it is difficult for visible light cameras to filter out the interference and obtain useful video images under bad weather or low illumination conditions, so the prevention capability of the whole security prevention system at night or under bad weather conditions is greatly reduced. In addition, the current video surveillance system must be continuously monitored by security personnel for 24 hours, and the video images should be analyzed and alerted manually. Otherwise, the system can only play the role of obtaining evidence after the incident without real-time alarm function. Therefore, on the whole, the current video surveillance system is still in the half-day, half-weather and semi-automatic state. Therefore, how to improve the ability of automatic alarm prevention in the period of high incidence of "dark night" has become one of the important issues that need to be solved urgently in the field of national public security prevention.

Infrared thermal imaging video alarm system, which is based on infrared thermal camera and visible light cameras and other hardware system, the use of infrared and visible light composite imaging, video image processing and automatic behavior analysis report to the police and other relevant software, and the existing video surveillance system of good lighting or artificial weather monitoring, forensics, later promoted to all-weather free of human care, under the condition of computer automatic real-time alarm function. Belong to the passive infrared thermal imaging technology of non-contact detection and recognition, good concealment, is not subject to electromagnetic interference, can remote hot target tracking precision, precision, detection capability, distance, intuitively display temperature field on the surface of the object, because the infrared thermal camera has concealment type detection function, because there is no need of light, so save the cost of making visible light, an intruder can't even know that they are being watched, and can penetrate smoke, fog, rain, smoke and such bad situation continuing work. The system can work at night or under severe weather conditions (such as heavy rain, fog, etc.), which can not only save a lot of manpower, but also realize all-weather real-time alarm all day. It not only makes up for the deficiencies of the existing video surveillance system, but also improves the automation degree of security system such as automatic identification and automatic alarm, which plays a very important social role and has a broad market.

1. Hardware System of Infrared Thermal Camera

Infrared thermal camera is a high-tech product used to detect the infrared radiation of target objects and convert the temperature distribution image of target objects into video images by means of photoelectric conversion and electrical signal processing. Its core components and technologies mainly include focal plane detector, follow-up circuit and image processing software. The focal plane detector is used to sense the temperature distribution of the target object and convert it into weak electrical signals. The subsequent circuit amplifies and logically processes the weak electrical signals so as to collect the temperature distribution of the target object clearly. The image processing software processes the amplified output electrical signal and presents the visible light image of the temperature distribution of the target object.

2. Video Alarm System

Based on digital and networked video surveillance, the video alarm system analyzes the video image content of the surveillance scene based on computer vision technology, extracts the key information in the scene, and forms the monitoring mode of corresponding events and alarms. It is a new generation of surveillance and alarm system based on video content analysis. It can automatically monitor, identify, track and analyze the targets in the video images, and filter out a large number of video surveillance videos that users do not care about through the automatic screening of computer programs. By analyzing and understanding the content of the video screen, it provides users with key information that is useful for monitoring and alarm. Thus it can be seen that the video alarm analysis technology has changed the passive receiving and feeling mode of traditional video surveillance from passive to active real-time analysis of the video recording on the monitoring site. The video surveillance system is mainly equipped with the functions of illegal intrusion alarm, reverse driving (walking) alarm, relic alarm, wandering alarm, infrared and visible image fusion, image enhancement, image de-jitter, target locking and tracking.