Video surveillance systems typically consist of various cameras such as dome cameras, bullet cameras, user-end devices like television walls and professional keyboards, and system devices like matrices, DVRs, and NVRs. Visible light video surveillance systems usually transmit video signals within a closed loop using optical fibers, coaxial cables, or microwaves. These systems form an independent and complete framework from capturing images to displaying and recording them, providing real-time, realistic depictions of monitored objects, while also offering real-time alerts for unauthorized activities.
As monitoring environments evolve and market demands increase, some limitations of visible light video surveillance systems become evident. For instance, the effectiveness of these systems greatly depends on the intensity of visible light and is compromised at night. Additionally, with the increasing prevalence of smog and haze in rapidly developing economies, visible light surveillance is severely impacted, with severe smog conditions rendering conventional security systems practically "blind." To overcome these limitations, a new security surveillance technology is quietly entering the field – infrared thermal imaging technology.
1. Effective Monitoring and Early Warning for Camouflaged and Concealed Targets
Conventional camouflage primarily aims to evade visible light observation. Criminal activities often take place at night, where perpetrators hide in vegetation or forests, making them hard to detect. Infrared thermal imaging devices passively receive thermal radiation emitted by the target, and human bodies and vehicles generally have higher temperatures and emit more infrared radiation than plants. As a result, they are difficult to camouflage, and the technology is less prone to false alarms.
2. Road Monitoring in Nighttime and Harsh Environmental Conditions
In recent years, smog and haze have become a frequent occurrence in many regions of China, significantly impacting transportation. Severe smog leads to highway closures, flight delays, and even cancellations. Traditional visible light security systems are rendered ineffective during such conditions. In contrast, infrared thermal imaging surveillance systems are not affected by smog and haze. An example in Figure 5a shows the results of capturing the same scene using a visible light camera and an infrared thermal imager when the PM2.5 level in Shanghai exceeded 530 in December 2013. The visibility with the visible light camera was only about 200 meters, whereas the long-wave infrared radiation, with wavelengths between 8 and 14 μm, can easily penetrate particles of 2.5 μm or less, ensuring visibility is unaffected and allowing for a clear view of buildings several kilometers away. Figure 5b demonstrates the detection of people and vehicles 800 meters away in smoggy conditions in Shanghai's Sheshan area. For larger targets like trains, the detection range can extend up to 10 kilometers.
3. Intelligent Front-End Image Recognition
Infrared thermal imaging systems, building on the existing intelligent recognition technology and algorithms of visible light systems, provide temperature information. Temperature data is unaffected by factors like light and color, leading to higher intelligent recognition capabilities and accuracy. For example, thermal imagers can be used for real-time people counting in public areas, providing more precise real-time data. Analysis can be conducted directly at the camera end to promptly raise alarms for crowd gatherings or other abnormal behaviors. Figure 6 illustrates a case where an infrared thermal imager is installed in a train station for people counting. Furthermore, thermal imagers can trigger alarms for individuals with elevated body temperatures, helping prevent the spread of diseases like avian flu.
In conclusion, infrared thermal imaging cameras, with their efficiency, intelligence, and stability in capturing images, have gradually become mainstream equipment in the security and surveillance sector. Their ability to work effectively in various environmental conditions, especially at night and in challenging climates, offers a new and vital tool for security surveillance. This technology is poised to make significant contributions to the field of security, addressing the limitations of conventional visible light systems and offering enhanced capabilities for various applications.
As monitoring environments evolve and market demands increase, some limitations of visible light video surveillance systems become evident. For instance, the effectiveness of these systems greatly depends on the intensity of visible light and is compromised at night. Additionally, with the increasing prevalence of smog and haze in rapidly developing economies, visible light surveillance is severely impacted, with severe smog conditions rendering conventional security systems practically "blind." To overcome these limitations, a new security surveillance technology is quietly entering the field – infrared thermal imaging technology.
1. Effective Monitoring and Early Warning for Camouflaged and Concealed Targets
Conventional camouflage primarily aims to evade visible light observation. Criminal activities often take place at night, where perpetrators hide in vegetation or forests, making them hard to detect. Infrared thermal imaging devices passively receive thermal radiation emitted by the target, and human bodies and vehicles generally have higher temperatures and emit more infrared radiation than plants. As a result, they are difficult to camouflage, and the technology is less prone to false alarms.
2. Road Monitoring in Nighttime and Harsh Environmental Conditions
In recent years, smog and haze have become a frequent occurrence in many regions of China, significantly impacting transportation. Severe smog leads to highway closures, flight delays, and even cancellations. Traditional visible light security systems are rendered ineffective during such conditions. In contrast, infrared thermal imaging surveillance systems are not affected by smog and haze. An example in Figure 5a shows the results of capturing the same scene using a visible light camera and an infrared thermal imager when the PM2.5 level in Shanghai exceeded 530 in December 2013. The visibility with the visible light camera was only about 200 meters, whereas the long-wave infrared radiation, with wavelengths between 8 and 14 μm, can easily penetrate particles of 2.5 μm or less, ensuring visibility is unaffected and allowing for a clear view of buildings several kilometers away. Figure 5b demonstrates the detection of people and vehicles 800 meters away in smoggy conditions in Shanghai's Sheshan area. For larger targets like trains, the detection range can extend up to 10 kilometers.
3. Intelligent Front-End Image Recognition
Infrared thermal imaging systems, building on the existing intelligent recognition technology and algorithms of visible light systems, provide temperature information. Temperature data is unaffected by factors like light and color, leading to higher intelligent recognition capabilities and accuracy. For example, thermal imagers can be used for real-time people counting in public areas, providing more precise real-time data. Analysis can be conducted directly at the camera end to promptly raise alarms for crowd gatherings or other abnormal behaviors. Figure 6 illustrates a case where an infrared thermal imager is installed in a train station for people counting. Furthermore, thermal imagers can trigger alarms for individuals with elevated body temperatures, helping prevent the spread of diseases like avian flu.
In conclusion, infrared thermal imaging cameras, with their efficiency, intelligence, and stability in capturing images, have gradually become mainstream equipment in the security and surveillance sector. Their ability to work effectively in various environmental conditions, especially at night and in challenging climates, offers a new and vital tool for security surveillance. This technology is poised to make significant contributions to the field of security, addressing the limitations of conventional visible light systems and offering enhanced capabilities for various applications.
