Get to know the power of infrared technology starting with thermal imaging cameras

　　Several years of the COVID-19 epidemic have made everyone familiar with temperature measuring equipment of various sizes and shapes (Figure 1). The most common sentence you hear is: “Come, let’s measure your body temperature.”
　　However, here The temperature measurement mentioned is completely different from the past. Compared with the temperature measurement method of clamping a mercury thermometer under the armpit, the current body temperature measurement method is more “advanced”. As long as you walk in front of the thermometer, they can measure people’s body temperature. How do these thermometers measure body temperature? How do they work? Let me give you a brief introduction.
The principle of infrared temperature measurement

　　First of all, we need to know a concept that any object with a temperature above 0K (-273.15°C) will emit thermal radiation, which is also called electromagnetic waves, and the higher the temperature of the object, the stronger the thermal radiation emitted. This means that as long as it is an object on the earth, it will emit thermal radiation. Infrared temperature measurement is based on this principle. It captures the thermal radiation emitted by the human body, and then displays the body temperature according to the intensity of the thermal radiation. The specific temperature measurement process of the infrared thermometer: first, the captured infrared radiation of the measured object is sent to the infrared detector through the optical system, and the detector converts the thermal radiation into a voltage signal, and then it is processed by the readout circuit , convert the voltage signal into a temperature value for output. Figure 2 shows an infrared thermal imaging picture.
　　Judging from the working principle and working method of the infrared thermometer, it has outstanding advantages such as fast measurement speed and non-contact. These advantages make the infrared thermometer play a huge role in the prevention and control of the new crown epidemic.
wide range of applications

　　In fact, the application of infrared technology is not limited to measuring body temperature, it has more and wider application fields. What is even more unexpected is that infrared technology appeared much earlier than people imagined.
　　As early as the 19th century, infrared imaging technology has appeared in the public eye. People at that time found that it was not only more convenient but also more effective to use infrared detectors to study the infrared radiation characteristics of astronomical stars. Later, infrared imaging technology showed strong application potential in the military field. For this reason, countries invested a lot of manpower and material resources in the development of infrared technology. Since then, infrared imaging technology has developed in full swing, and technologies such as infrared imaging, infrared tracking, infrared early warning, infrared countermeasures, and infrared guidance have been widely used in the military. After 1970, infrared technology gradually shifted from the military field to the civilian field. Various advanced infrared technologies, such as infrared remote sensing, infrared temperature measurement, infrared detection, infrared security, infrared anti-counterfeiting, etc., have shown their talents in all walks of life.
Powerful Application Technology

　　Ordinary people may feel a little unfamiliar with these proper nouns mentioned above. Next, the author will combine typical application cases around us to help everyone better understand the power and magic of infrared technology.
　　Infrared remote sensing technology uses infrared devices such as infrared cameras and infrared scanners to detect the infrared radiation of vegetation and other ground objects at a relatively long distance, and then determines the nature, distribution and status of the ground objects by analyzing the differences in infrared characteristics. . Infrared remote sensing technology is widely used, one of which we are more familiar with is the detection of air pollution in cities. During the detection, the spectral information of the city is first collected by infrared remote sensors, and then according to the characteristics of different spectra, the main pollutants and their spatial distribution in the city are inverted in real time by computer.

Figure 2 Infrared thermal imaging picture

Figure 3 Infrared thermal imaging image showing the heat from the chimney of the energy station

　　Infrared security at night or in bad weather conditions, ordinary visible light cameras cannot work normally, and the observation distance is greatly shortened. If artificial lighting is used, it is easy to expose the target; if low-light night vision equipment is used, external light is still required. Such equipment can still work in the city, but when working in the field, due to the greatly shortened observation distance, the observation effect of the equipment will deteriorate or even fail to work normally. At this time, infrared security equipment can show its talents.
　　The infrared thermal imaging camera can convert the invisible infrared energy emitted by the object into a visible thermal image, and different colors on the thermal image represent different temperatures of the measured object. Since the infrared thermal imaging camera can actively receive the infrared radiation emitted by the target, whether it can work normally has nothing to do with the surrounding weather conditions. In addition, the infrared thermal imaging camera has a good stealth effect, so it can be used in security monitoring such as night safety monitoring and fire monitoring. field has a wide range of applications.

Figure 4 night vision detection

Figure 5 anti-counterfeiting label

　　Take fire monitoring as an example. Large-scale forest fires are often caused by invisible hidden fires, and it is difficult to find the signs of such hidden fires with existing common methods. The use of infrared thermal imaging cameras can quickly and effectively discover these hidden fires, accurately determine the location and scope of the fire, find the ignition point through the smoke, and achieve early knowledge, early prevention, and early extinguishment.
　　Infrared anti-counterfeiting technology is usually used in the manufacture of anti-counterfeiting inks. Infrared anti-counterfeiting ink is usually made by adding one or several materials that absorb near-infrared light into the ink. In actual use, you only need to use anti-counterfeiting ink to draw the desired information on the printed matter. The information leaves no trace under visible light conditions, but can be decoded by infrared detection instruments.
　　The above-mentioned infrared technology has improved measurement accuracy, product quality, work efficiency and automation, and greatly promoted the prosperity and development of related industries. In recent years, with the rise of emerging technologies such as “smart +”, the development space of infrared technology has also been further expanded. For example, infrared technology has fully entered the field of automatic driving. Human safety escort.
　　It is conceivable that in the future, infrared technology will be more and more widely used in people’s lives. Although this is the convenience brought to us by scientific and technological progress, it is also inseparable from the assiduous research of generations of scientists.