Infrared thermal imager application in the field of fire

With the development of photoelectric information, microelectronics, network communications, digital video, multimedia technology and sensor technology, security monitoring has evolved from traditional analog to digital, intelligent, and networked. Due to the advantages of digital signals such as strong anti-jamming capability, low distortion, limited distance transmission, easy storage and query, digital video technology has been rapidly developed and widely used.

The digitization of the image first converts the collected analog signal into a digital signal, which fundamentally solves the problem of data compression, and can be combined with the network, breaking the limitations of the traditional analog monitoring by the area and distance, and achieving the digital The seamless connection between video surveillance and other subsystems in the security system can realize centralized monitoring, storage, control and management on a unified operation management platform, and realize the sharing of information resources and hardware and software resources.

The following briefly introduces the application of infrared thermal imaging technology, digitalization and networked video recording and remote monitoring technology in the security system.

First, what is infrared thermal imaging?

Infrared thermal imaging Visible light wavelengths that the human eye can sense are 0.38-0.78 microns. Electromagnetic waves, which are usually longer than 0.78 microns, are called infrared rays. In nature, all objects radiate infrared light of different wavelengths, so it is possible to detect the infrared wavelengths between the monitoring target itself and the background using a special detection device, so that different infrared images can be obtained. Such infrared images are called thermal images. The same target of the thermal image and visible light image is different, the thermal image is the target surface temperature distribution map, or infrared thermal image is the target surface temperature distribution map can not be directly seen by the human eye, only through specialized equipment to convert adult eyes A thermal image that characterizes the temperature distribution of the target surface can be seen. Infrared thermography features In nature, all objects whose absolute temperature is above -273°C will emit infrared rays. Infrared rays (or thermal radiation) are the most widespread radiation in nature. Atmospheres, smoke clouds, etc., absorb visible light and near-infrared light, but are transparent to 3-5 micron and 8-14 micron infrared light. Therefore, these two bands are called infrared "atmospheric windows." Using these two windows, we can clearly observe the situation in front of us on a completely dark night or in the harsh environment of smoke clouds. Due to this feature, infrared thermal imaging technology can be used in security night surveillance and fire protection monitoring systems in various locations. The infrared thermal imager uses infrared thermal imaging technology to detect the infrared radiation of a target object, and converts the temperature distribution image of the target object into a video image through photoelectric conversion, signal processing, etc. The device is called an infrared thermal imager. Infrared thermal imagers can be divided into two major types of refrigeration type and non-refrigerated type. The refrigeration type has a high thermal sensitivity and a complex structure, and is generally used for military purposes. The non-refrigerant type has a lower sensitivity than the refrigeration type, but its performance can satisfy most military applications and almost all civil fields. Because it does not need to be equipped with refrigeration equipment, the reliability and cost-effectiveness of uncooled infrared thermal imagers are higher than those of refrigeration models.

Application of Infrared Thermal Imager 1. Target monitoring at night and in adverse weather conditions Equipment that requires visible light can no longer work properly. If artificial lighting is used, it is easy to expose the target. If low-vision night vision equipment is used, it also works in the visible light range and still requires external light illumination. The infrared thermal imager passively accepts the target's own infrared heat radiation, and can work normally both during the day and night, and it will not expose itself. Also in the harsh weather conditions such as rain and fog, due to the short wavelength of visible light, the ability to overcome obstacles is poor, so the observation effect is poor, but the infrared wavelength is longer, especially in the thermal imager working on 8-14um. The ability of rain and fog is strong, so at night and in bad weather conditions, infrared thermal imaging monitoring equipment can still monitor various targets normally.

2. Fire protection monitoring As infrared thermal imager is a device that reflects the surface temperature of an object and forms an image, it can be used as an on-site monitor in addition to nighttime. It can also be used as an effective fire alarm device. In the early stages of all firefighting hazards, disasters are often caused by No obvious hidden fire caused. With existing common methods, it is difficult to find such hidden fire signs. The use of infrared thermal imager can quickly and effectively find these hidden flames, and can accurately determine the location and scope of the fire, through the smoke found that the fire point, so that as early as possible to prevent early, extinguished as early as possible.

3, camouflage and covert target recognition camouflage is mainly to prevent visible light observations, criminals usually cover the grass and the forest when committing crimes, due to the harsh environment and human visual illusion, easy to produce erroneous judgments. The infrared thermal imager passively receives the target's own thermal radiation. The human body and the vehicle's temperature and infrared radiation are generally much larger than the temperature and infrared radiation of the vegetation. Therefore, it is not easy to disguise, and it is not easy to produce erroneous judgments.

Second, what are the characteristics of infrared thermal imaging? Objects around us emit visible light only when their temperature is above 1000°C. In contrast, all objects around us at absolute zero (-273°C) will constantly emit thermal infrared rays. For example, we can calculate that the thermal infrared energy emitted by a normal person is about 100 watts. Therefore, thermal infrared (or thermal radiation) is the most widespread radiation in nature. In addition to the universality of the existence of heat radiation, there are two other important characteristics.

1. Atmospheres, smoke clouds, etc., absorb visible light and near-infrared rays, but are transparent to thermal infrared light of 3 to 5 micrometers and 8 to 14 micrometers. Therefore, these two bands are called "atmospheric windows" of thermal infrared rays. The use of these two windows allows people to clearly observe the situation in front of them on a completely dark night or in a scene where smoke clouds are densely covered. Thanks to this feature, infrared imaging technology provides advanced night vision equipment for the military and an all-weather front-view system for aircraft, ships, and tanks. These systems have played a very important role in the Gulf War.

2. The size of the thermal radiation energy of an object is directly related to the temperature of the surface of the object. This feature of heat radiation allows people to use it to carry out non-contact temperature measurement and thermal state analysis of objects, thus providing an important detection method and diagnostic tool for industrial production, energy conservation, environmental protection and so on.

Third, infrared thermal imager According to the characteristics of the object can emit infrared, various countries competing to develop a variety of infrared thermal imaging equipment. In 1964, Texas Instruments first developed the first-generation thermal infrared imaging device called the infrared front-view system (FLIR). This type of device uses an optical component motion machine to perform thermal radiation on the target. Decompose the scan, and then use photodetectors for light-electrical conversion, and finally form a video image signal, and display on the screen, infrared front-view system is still an important device on military aircraft, ships and tanks. In the mid-1960s, AGA Sweden and the Swedish National Electric Power Bureau developed a thermal infrared imaging device with a temperature measurement function based on an infrared front view device. This second generation infrared imaging device is often called a thermal imager. In the 1970s, the French company Tom Hoe developed cold infrared TV products without cooling. In the 1990s, there was a refrigerating and non-cooling type of focal plane infrared thermal imaging product. This is the latest generation of infrared television products that can be used in large-scale industrialization to increase the application of infrared thermal imaging to a new stage. Infrared thermal imaging products can be classified into two types of refrigeration-based non-refrigerated types. Infrared television products and non-refrigerated focal plane thermal imagers are non-refrigerated products, and others are refrigeration infrared thermal imagers. The thermal imager can not only observe the target in real time, but also can perform dynamic analysis through the “hot trace” of its trajectory. Because the thermal divergence of the general object has a certain time, the heat divergence of some objects takes a long time. For example, the smoke ignited by troops, vehicles that have been launched, etc. can leave "hot traces."

Fourth, the role of infrared thermal imager in the fire. Forest fires In large areas of forests, fires are often triggered by unobvious hidden fires. This is the root cause of devastating fires. With the existing common methods, it is difficult to find such hidden fire signs. However, using an aircraft patrol with an infrared thermal imager, these concealed fires can be discovered quickly and effectively, eradicating the fire in the first place. The Canadian Forestry Institute began a forest fire test as early as 1975. From a plane, it inspected potential fire sources that had not yet ignited. The Canadian Forest Research Center used helicopters to use the AGA 750 Portable Thermal Imager. It found 15 times during a fire season. fire. Cereal granaries tend to self-ignite, and this spontaneous combustion often takes a long time, is swift, and has large losses. At present, thermometers are generally used to measure temperature changes in the grain store to prevent them. The use of thermal imaging cameras can accurately determine the location and extent of these fires, so that early warning can be prevented and extinguished early. The use of thermal imaging camera is simple, fast, and extinguished in time.

B. Electrical equipment fire detection infrared thermal imager can also be used to detect the bad contact of electrical equipment, as well as overheated mechanical parts, in order to avoid serious short circuit and fire. During the four years from 1980 to 1983, overheating inspections were performed on 20 electric power plants, 8 substations, and 24 high-voltage lines in the North China Electric Power Network using thermal imaging cameras. More than 500 abnormal heating points were found. Severe overheating was 100. No fire accident occurred due to timely handling. In foreign countries, statistics from US insurance companies indicate that more than 25% of all hidden dangers in electrical equipment are caused by fire due to poor contact with plugs. For all devices that can be seen directly, infrared thermal imaging products are able to determine the heat hazard of all connection points. For those parts that cannot be seen directly due to shielding, heat hazards can be found on the basis of the fact that heat is conducted to the outer parts. This is the case for traditional methods, except for body inspections and cleaning joints. There is no other way. Circuit breakers, conductors, busbars and other components are tested for operation and infrared thermal imaging products cannot be replaced. However, infrared thermal imaging products can easily detect loop overload or three-phase load imbalance. Most of the heat hazards are found on the motor control equipment, and some hidden dangers are found in the switchgear and power disk. For example, after a fire in a major motor control center within a federal government office building, a preventive maintenance of the equipment is performed every six months. After the fire, two repairs were carried out and an infrared thermal imaging product inspection was conducted. As a result, the number of serious hidden troubles before the repairs was three, and the number of three after preventive maintenance. So the necessity of infrared thermal imaging product inspection is obvious. In addition, the use of infrared thermography products instead of the traditional method of cleaning and fastening can save a lot of money. There are two reasons for this savings: first, the inspection of infrared thermal imaging products is performed very quickly, rather than the traditional method that takes a lot of manpower to clean and fasten the equipment. In addition, when infrared thermal imaging products are inspected,

The equipment is not required to be powered off. It is only after finding out the hidden danger that it requires a short power outage during the repair. And the power outage for repairing individual hazards is only partial, and the power outage time is very limited. It may even be scheduled to be repaired during planned power outages. Here are a few examples.

1. A U.S. asset management company implements a complete maintenance program that includes all motor control equipment, lighting, power disks, and switchgear (excluding breaker trip tests). The fees are based on workload. The average maintenance cost for a typical office building (250,000 square feet, 10 floors) is $6,500. The same building is inspected with infrared thermography products, and inspections of all motor controls, switchboards, and switchgear can be completed in one day (and includes various mechanical equipment). The inspection service fee for infrared thermography products is approximately 600 to 800 US dollars. . Therefore, the cost of infrared thermal imaging products is only 1/10 of the cost of traditional methods.

2. Before signing an infrared thermal imaging product inspection contract, an electronic equipment manufacturer uses a 4 day power outage, 3 groups of 5 electricians for traditional maintenance, and the workers work 12 hours a day to clean and tighten all switching devices. , motor control equipment and power disk connection points. The labor cost for these jobs is $30,000. The infrared thermal imaging product inspection for the same equipment was also conducted for four days and completed with the assistance of two factory workers, and its cost was only 3,000 US dollars.

3. A large office/inn/commercial commercial complex conducts traditional maintenance of high and low switchgears every three years. The cost of cleaning and fastening work during maintenance is at least US$20,000. The infrared thermal imaging product inspection of the same device took only 12 hours, costing only 2,000 US dollars, and found 12 hidden dangers, of which two were serious hidden dangers that could cause fire.

4, through the infrared thermal imaging product inspection and analysis, a small US factory will reduce the annual cost from 160 to 40 hours. If you calculate at a cost of $25 per hour (including overtime), you can save 120 hours per year, which means you can save $3,000. According to the above experience of the United States, the use of infrared thermal imaging products to replace the regular cleaning and fastening work in traditional maintenance can save 50% to 90% of the cost, and can effectively prevent the occurrence of fire. For example, during the July-August period of 1985, the Washington Post reported on the front page the fires, personal injuries, property damage, and loss of production and taxation caused by the accidents of many electrical equipment that occurred almost daily. . For example, a power outage at a local hotel caused a loss of 6.5 million U.S. dollars. In order to avoid the blackouts mentioned above, many commercial and industrial organizations often spend a lot of money to perform preventive maintenance work. Unfortunately, these jobs not only often fail to discover hidden dangers, but also cause new electrical hazards. Therefore, inspection of infrared thermal imaging products of electrical equipment can replace traditional preventive maintenance work in many aspects. According to the “Operations of Equipment and Production Control Technology” of the United States, No. 375, it is pointed out that both new and old buildings can benefit from the inspection of infrared thermal imaging products. Nearly 50 companies in the United States provide infrared thermal imaging product inspection services. All electrical equipment and power distribution systems for customers include high voltage contactors, fuse discs, main power circuit breakers, contactors, and all distribution lines. Motors, transformers, etc. are used for infrared thermal imaging inspections to ensure that all operating electrical equipment of the customer is free from potential thermal hazards and effectively prevent fires. Statistics from US insurance companies have also shown that the inspection of infrared thermal imaging products for all electrical equipment can greatly reduce unsafe factors and save a lot of insurance expenses.

Below are some facilities that need infrared thermal imaging inspections.

1, various electrical devices: can be found loose joints or poor contact, unbalanced load, overload, overheating and other hidden dangers. The potential impact of these hidden dangers is the creation of arcs, short circuits, burning, and fire.

2. Transformer: The hidden troubles that can be discovered are loose joints, overheating of the casing, poor contact (tap converter), overload, unbalanced three-phase load, and poor cooling pipe blockage. Its effect is to produce arcs, short circuits, burns, and fires. Rewinding costs 10,000 to 50,000 U.S. dollars, and it is replaced by 80,000 to 140,000 U.S. dollars. The duration is several weeks or months.

3, motor, generator: The hidden danger that can be found is the bearing temperature is too high, unbalanced load, the winding is short-circuited or open circuit, the carbon brush, slip ring and collector ring are heated, the overload is overheated, the cooling pipeline is blocked. The effect of a faulty bearing can cause damage to the core or winding, and a faulty carbon brush can damage the slip ring and the collector ring, thereby damaging the winding coil. It may also cause damage to the drive target. The motor rewinding (5000 hp) needs 50,000-100,000 US dollars, and the replacement needs 100,000-200,000 US dollars. The duration is several weeks to several months.

4. In addition to electrical equipment maintenance inspections, infrared imaging inspections are also very effective in detecting leaks on rooftops, energy-saving inspections, environmental protection inspections, security theft, forest fire prevention, non-destructive testing, quality control, and medical inspections.

C. Fire site search and rescue infrared application is a detection technology based on the infrared heat radiation properties of the object itself. The infrared search and rescue technology extended in the field of firefighting in this technology can greatly enhance the ability of firefighters to clearly display the shape of the object under heavy smoke, heat, and collapse of buildings. And each point of the temperature, to help firefighters quickly search for distressed personnel and valuables, but also timely detection of fire or the largest source of fire, thereby reducing the time of fire suppression, reduce the loss of goods, is a helpful tool for fire scene rescue work. Compared with traditional fire-fighting and rescue methods based on naked eye detection, infrared thermal imagers based on infrared technology can help firefighters avoid the interference of smoke and darkness, clearly observing, discovering, and mastering the real situation of the fire, and make scientific as soon as possible. Decision and correct deployment.

D. Firefighting accident investigations Similarly, infrared thermal imaging products are also useful in fire and explosion accident investigations. Infrared thermal imaging has become more and more important in the legal affairs of accidents such as fires, especially around complex technical issues related to loss of life or property. Because of the losses caused by fires and explosions, often involving heat hazards, heat transmission, etc., and these conditions can be quickly observed and recorded with infrared thermal imaging products, so infrared thermal imaging is a powerful image evidence that can make non- Professionals are also clear and can make fair decisions and trials of losses. The following are examples of the use of infrared thermal images in several fire and explosion accident investigations. U.S. local governments and insurance companies often require an analysis of the causes of personal and property damage. Corresponding investigations may not reveal criminal activities such as murder or arson. However, investigations can discover equipment failures and damages, and how to avoid these problems in the future. Thermal images on an already-burned building can often give people an idea of ​​how the fire or explosion actually occurred. And the process of fire, explosion or equipment damage is reproduced experimentally to supplement the understanding of the incident. Infrared thermography provides a very good visual measure of the analysis and reproduction of accidents caused by heat. Experimental infrared and video recordings of fire, explosion, and equipment damage allow people to have a deeper understanding of their causes.

Here are a few examples.

1. In a test car, a gallon of gasoline is placed in the driver's seat. A pound of explosive is placed under it. Explosives are detonated remotely using electronic equipment. Infrared thermal imaging records the test vehicle's condition approximately 0.04 seconds after the explosion, showing the fireball emitted from gasoline, and the range of radiation emitted after the accident, and the subsequent development of the explosion. This heat profile, which can only be obtained using infrared thermal imaging, shows the range of heat transfer during and after explosion. The ejection trajectories of the burned fragments are easily discernible by replaying the heat image video, and these trajectories are often not found in replaying visible light videos. The residual thermal image on the exterior of the vehicle can indicate the high temperature distribution area, which is often used as a clue to find the source of the accident.

2. Another similar test is to use abandoned houses as the test target. In this experiment, 0.25 pounds of C4 explosives were placed under a tank of one gallon of gasoline. The results showed the initial state of the experimental house, the initial thermal state and a series of subsequent conditions, including the 3 seconds of thermal state after the explosion, the residual heat from the explosion and its initial ignition source, and further expansion after a few minutes. It can be seen for the fire. In the United States, the analysis of the cause of fire and the source of fire is similar to the analysis of explosion accidents. The identification of thermal images can help people determine the cause of the fire and provide information on the cause of the accident for a detailed examination of the fire point. Here are a few examples. For example, infrared thermal imaging can show the process of a fire in a car. Acetone and polystyrene are mixed together to form a spherical plastic mass that is located near the steering column in the engine compartment and is ignited. Infrared thermal video can show about 3 minutes after the fire, local heat in the protective glass window is obvious. And it can show that hot gas enters the passenger compartment through the fire wall, and the higher radiation emitted from the window confirms this situation. In addition, infrared thermal image recording shows the leakage of volatile gases from the engine room, showing the process of leakage and combustion of volatile liquids. In addition, the infrared thermal image recording shows that the flame in the fire zone is extinguishing. The use of thermal images clearly describes the stages of the misfire process and it is being used in the training of fire investigators. An infrared thermal image of a misfire test in an abandoned house can show a firefighter placing a igniting liquid mixture and shaking a chloride powder stored in a cabinet, and the subsequent development of the fire, from top to bottom within the building The formation of hot air, from these infrared thermal images can be seen, the speed of heat conduction from the ignition point in the cabinet is very fast. Fires and explosions caused by mechanical or electrical equipment manufacturing problems are often of concern to investigators. For example, in a house, a fire was caused by a malfunction of a Heater, and a person inside died of smoke. When checking a floor heater, as long as it is exactly the same as the heater that caused the fire, to obtain the thermal image of the heater when working, you can see the hottest hot test point on the thermal image at the high temperature limit. Near the switch, it was determined that the fault was caused by the copper wire. This fault was enough to ignite the debris and powder inside the heater, and to protect the bottom box of the high-limit switch. The high temperature spot seen on the thermal image exceeds the temperature rating of the wire insulation. Wires In this environment, insulation aging will inevitably lead to a short circuit, causing a fire. Thermal images not only provide a quantitative temperature value, but also provide a clear and intuitive description of the way the fault was generated. An overheated belt traction wheel that attempts to drive a locked compressor. The question answered from this test is how high the temperature generated between the V-belt and the belt traction wheel can ignite the flammable gas near the device.

A flammable gas with a flash point temperature of 6000F was ignited and a nearby compressor exploded, causing serious damage and casualties to an oil processing plant. Using an infrared thermal image to measure the temperature at the outer edge of the wheel, the information obtained is used as a boundary condition for the finite element heat conduction analysis. The calculation results show that the temperature between the fan belt and the belt is above 8000F. This temperature is to ignite the flammable gas that was inadvertently leaked from the plant's oil processing plant equipment. After the fire broke out, U.S. investigators collected evidence from eyewitnesses, fire departments, police and the scene. In situations where mechanical or electrical equipment may cause a fire, infrared thermal imaging data obtained from past energy accounting or equipment analysis may be useful. For example, a thermal image of an air handler with an overheated motor and a fan belt traction wheel. The heat emitted from the belt and belt traction wheels quickly passes through the metal enclosure outside the device. Later, if an air delivery device is suspected of causing a fire, the near-infrared thermal image of the device can be an important basis for elucidating the cause of the fire.

V. Application of Infrared Thermal Imager in Safety Precautions External thermal imagers have been widely used in security systems because of their features and functions, and have become the stars in security monitoring systems. The infrared thermal imager has a concealed detection function. It does not require visible light, and it can make criminals not know their place of work and existence. As a result, misjudgments are made and criminal activities are exposed. In some very important units, such as: important administrative centers, bank vaults, confidential rooms, military sites, prisons, etc., are particularly used in this type of infrared thermal imager, which can be in operation 24 hours a day, and at any time Analyze the background data. Once it changes, an alarm can be issued in a timely manner, and the situation can be handled automatically through the processing of smart devices, and the situation can be reported at any time to obtain further processing advice. For these special important departments, the sensitivity of their prevention is much higher than that of other defense systems. For example, when these units are off-duty, as long as someone is hidden inside, the system will generate an alarm signal. As everyone knows, border defense is a very difficult thing. China’s borders are long and the oceans are vast. Because of the harsh environment, many systems cannot play a good preventive role. Especially in the days of rain, snow, fog, and windy weather, border patrol is also a very bitter task. . If personnel are patrolled and observed with a telescope, the wavelength of visible light is often short, so the effect of observation is poor, resulting in missed inspections, false positives, and missed inspections. The infrared thermal imager can detect infrared rays with a short wavelength, so it can be observed at a long distance, especially for weather.

According to Hong Kong’s “Oriental Daily” report, the Hong Kong police placed five sets of infrared thermal imagers in a certain border area. During the trial process, many illegal immigrants cases were successfully cracked and the efficiency was much higher than that of manual inspections. Therefore, the Hong Kong Police plan to purchase a new system this year to strengthen the prevention of illegal immigration cases. On the coast, infrared thermal imagers can be used to quickly track ships coming and going. Now smuggling by the sea, often using "big fly" to carry out, these "big fly" without light, high horsepower, strong mobility, often easy to get rid of our private officers and border guards to track, with infrared thermal imaging instrument, can be far Keeping track of these "big flies" is the dead end in the radar. This system can also operate normally, especially in the dark and bad weather, can fully display its good features. By the same token, infrared thermal imagers can be applied to the perimeter of the living quarters to prevent the perimeter of important areas from being able to achieve the effects that are not easily achieved by the general surveillance system. It is well known that the community's prevention mainly prevents the entry of criminals and the general surveillance system. It is easy to produce dead angle during installation, which is not conducive to full control of the monitoring surface. Another point is that it is prone to interference, such as the invasion of small animals. Installing an infrared thermal imager can overcome the above two shortcomings and reduce false positives. In China, with the expansion of urban transportation and the extension of various highways and railways, the normal operation of these systems has become a major problem. Especially during nighttime security inspections, it has become a problem. Today, infrared thermal imagers are installed. The aircraft can successfully complete these tasks. It can find obstructed vehicles, faulty cars, and targets that need to be locked. In foreign countries, many units have actually used these systems to conduct inspections. VI. Application of infrared thermal imager in remote monitoring Digital and networked video and remote monitoring technology The development of analog video surveillance has not been able to meet people's higher requirements. Digitalization is the only way. Digitization is a prerequisite for compression and image processing. Digital video surveillance system adopts digital processing, codec and network technology, which can overcome the limitation of analog system better. Its advantages are: the image can be transmitted on the network after being digitized, and it is not limited by distance, and is not easily affected by interference. Improve image quality and stability. Second, using existing networks eliminates the need for repetitive wiring. Once again, digital storage becomes possible. The compressed video data can be stored in a disk array or stored on a compact disc. The query is quick and easy. Network type embedded hard disk video recorder The network type embedded hard disk video recorder is a digital video monitoring equipment integrating digitization and network integration and built on embedded processor and embedded operating system. It integrates matrix switching, screen division, and video recording. Remote control, network transmission and many other functions. Its functions are mainly represented by real-time hardware-synchronized compression of video and audio signals, compressed data streams stored on hard disks, real-time video and sound previews, video and audio signal switching, camera and pan-tilt control, local video file playback, and real-time network transmission. Remote file playback and download, support for streaming protocols (RTP/RTCP, RTSP), support for IE browsing, and two-way voice intercom. Application Cases Here are two successful examples of the application of infrared imaging technology combined with digital network technology. The digital video surveillance system in the case is a monitoring platform that integrates infrared thermal imaging, digital and networked video, and remote monitoring technologies. The system consists of an infrared thermal imager, a network-based embedded hard disk recorder, network transmission equipment, and back-end management storage devices. It can use visible light and infrared technology to achieve all-day, all-weather monitoring, monitoring and monitoring through a variety of transmission means, so that the monitoring center can control the scene in an intuitive and real-time manner, even at night, fog, smoke, woods, etc. In the conditions, the conditions of the site can also be clearly displayed, and the front device can be manipulated at the monitoring center for key monitoring. At present, the system has been widely used in defense, public security, fire protection, forest fire prevention, traffic management, security of key facilities, beach protection monitoring, port management supervision, airport supervision, and fire warning of yards and warehouses throughout the day, all-weather monitoring.

Case 1: Forest fire prevention monitoring system in a city Forest fire is one of the most important disasters in forestry. Forest fires are characterized by suddenness, randomness of disasters, and huge losses in a short time. Therefore, once there is a fire, it must be taken at a very rapid rate to take measures to save the fire. Whether the fire is timely or not and whether the decision is appropriate depends largely on whether the discovery of the forest fire behavior is timely, whether the analysis is accurate and reasonable, and whether the decision-making measures are appropriate. Using advanced technology, using high-tech means to strengthen forest fire prevention work, making decisions and scheduling in the shortest possible time, so as to win valuable time for forest firefighting, minimizing losses is an inevitable trend in the development of forest fire prevention management. When a fire occurs, especially in the case of a forest fire, the smoke produced by the flame is large, often covering the real fire point and the spread of fire. The thermal imaging camera has a strong ability to penetrate the smoke and can effectively detect the real ignition point and the spread of fire. In the case of forest fires where ground fires have been extinguished, underground fires often exist underground, and as a result, they are often rekindled. The infrared thermal imager can monitor the temperature of the forest surface after a fire and timely discover the anomaly of the surface temperature to determine the possible location of the underground fire. The system design consists of two parts: the monitoring front end (monitoring point) and the monitoring center. The figure is a network structure diagram. The system is equipped with five fire monitoring front-ends, each of which is equipped with an infrared thermal imager and a low-illuminance long-focal-length visible light camera at each surveillance command point. The coverage radius is 1-5km. It uses city electricity and solar energy to power the front-end equipment and is equipped with an outdoor all-weather platform. And infrared thermal imager special protective cover, infrared thermal imager and visible light camera share a head. The task of the monitoring front-end is to take charge of the collection and control of video signals in various forest areas. The other devices in the monitoring front-end also include wireless image transmission equipment, wireless command receiver equipment, digital optical transceivers, solar power supply equipment, and lightning protection equipment. The monitoring center consists of monitoring workstations, matrix control hosts, video walls, and hard disk recorders. The image data of the monitoring workstations is connected to the branch office network. The system adopts the TCP/IP protocol. Any authorized computer in the network can monitor the front-end monitoring. The image of the point. The system adopts a modular structure, has good expandability, and can increase or decrease monitoring points at any time. The main functions of the monitoring center are early warning, display, control, video recording, and network transmission. See Figure 1 for the system structure diagram.

Case 2: Monitoring system of a border defense unit There are tens of thousands of kilometers of coastline and border line in China, and it is adjacent to many countries. Accurate and timely control of the military situation in the coastal and coastal defense areas is of great significance to effectively defending the territorial sea and territory of the motherland. The establishment of the Coastal Defence Remote Video Surveillance System and the monitoring of key ports, posts and sensitive areas will enable our military intelligence agencies to monitor the current situation of the coastal frontline in an intuitive and timely manner and improve the real-time and comprehensive processing capabilities of intelligence acquisition. It can effectively prevent illegal activities such as smuggling, flight, smuggling, and drug trafficking. Since the general disguise is based on the prevention of visible light observation, criminals committing crimes are usually hidden in the grass and forests, the harsh environment and human visual illusion, it is easy to produce missed judgments, misjudgment, and infrared thermal imager is passive Accepting the target's own thermal radiation, the human body and the vehicle's temperature and infrared radiation are generally much greater than the temperature and infrared radiation of the vegetation, not easy to disguise, nor easy to produce erroneous judgments.红外热成像系统能从杂乱的背景和树丛之中识别目标，并且还能透过灰尘、云层、烟、烟雾、薄雾、小雨看清目标，提供详细的环境信息。其监视的效率高于原来人工的巡查监视方式，可大大减少由人工巡查监视方式造成的漏查、误查和失查的现象。系统设计由两部分构成：前端监控点和监控中心。监控前端设在边防哨所，包括红外热成像仪及低照度长焦距可见光摄像头各一套，覆盖半径视监控区域而定，一般在1-5km。采用市电及太阳能给前端设备供电，红外热成像仪及可见光摄像头共享一个云台，负责所辖区域视频信号采集、存储及控制，其它前端设备还包含嵌入式硬盘录像机、数字光端机、太阳能供电设备、避雷设备等。监控中心由监控工作站、矩阵控制主机、电视墙、网络交换机等设备组成，监控工作站的图像数据接入军区网络，系统采用TCP／IP协议，网内经授权的任何一台计算机均可作为监控点。系统结构图参见图2。上述二例介绍的融合了红外热成像、数字化及网络化录像及远程监控技术的监控平台已被成功地应用在森林监控和边防监控的案例中，并取得了较好效果。