How Does Thermal Imaging Work?


Constant technological development is a regularity of the functioning of modern society. This is what makes modern society fundamentally different from primitive or medieval society. Primitive society had a basic characteristic associated with the need to survive in difficult conditions without the necessary means of subsistence. At that time, there were the most primitive samples of weapons that could be made by yourself in a short period of time. This is, for example, a spear, a hammer, a scythe, etc. They were made from trees and stone, that is, from what was constantly available. If we analyze the effectiveness of their use, we can conclude that they were enough for hunting or farming. Later, in the Middle Ages, scientists made a significant contribution to the scientific field. Researchers understood that the subjugation of nature is possible only by applying reason along with skill. This contributed to the intensification of scientific research and, as a result, the wheel, telescope, compass, horseshoe, etc. were invented. Now people felt more confident in performing various tasks and used scientific achievements in various spheres of human activity.

The beginning of the 19th century was marked by the accelerated development of research in the field of optical devices. Optics became in demand in almost every profession, and the creation of better lenses with more powerful diopters became a prerequisite for the emergence of devices capable of bringing objects closer. Scientists have been actively developing devices that can be used not only during the day, but also at night, because some activities are more effective at night. This need led to the creation of the first devices with a thermal imaging method of operation, the features, and characteristics of which will be discussed below.

What Is Thermal Imaging?

Have you ever observed an image in which red spots in the form of people or other objects are clearly visible? This is called a thermal image. Its invention and research were carried out at the end of the 19th and the beginning of the 20th century. So, the researchers noticed that in the case of passing red light through a prism, you can observe prints on the surface that is behind the prism. In this way, the transmission of thermal infrared rays through a certain surface created a higher temperature and made it possible to notice such temperature jumps on another surface. Thermal imagers are not thermometers, but they record the temperature of certain objects and, depending on how high it is, display different objects in certain colors. For example, an object with the highest temperature in a specific environment will have a bright red color, those with a lower temperature will have a more orange image. Cooler objects will have a bluish or blue color. Another feature of the functioning of thermal imagers is that they scan the temperature of only those objects that have a temperature higher than that inherent in the specific environment in which the thermal imager is used.

How Does Thermal Imaging Work?

All objects that are in a specific environment emit a certain amount of heat. It cannot be seen with the naked eye but can be felt if the amount of heat generated is significant. Thermal reflection on the surface works in such a way that the heat captured by the thermal imager passes through a prism that absorbs this heat and reflects the radiation in the form of a thermal image on the surface. Thus, it is possible to observe different colors on the surface, depending on the intensity of heat release from each specific object.

It should be noted that thermal imaging cameras and their functionality are used not only in the most important industries, as it was before. So, earlier the use of these devices prevailed only for military needs. This was caused both by the high price of the materials from which the devices were made, and by their low demand in other industries at that time. At the end of the 20th century, there was a significant reduction in the cost of materials for the manufacture of thermal imaging devices, which allowed their use in other areas of human activity. Thus, the active use of thermal imagers is observed during hunting mostly at night. This helps the hunter to track an animal on “hot trails” or to track an animal that has already been wounded and is leaving a trail of blood behind. Thermal imagers, unlike flashlights, do not confuse traces of blood with paint or other liquid. Also, thermal imagers are actively used in medicine to make a more accurate diagnosis and prescribe more effective treatment. Thermal imaging devices are also used by guards, for whom it is important to keep the object and everything that happens around it under control. Ultra-sensitive cameras can record the movement of an object with an elevated temperature and make it possible to take appropriate measures to eliminate the danger that may threaten the object. Thermal imagers are also used in law enforcement and search-and-reconnaissance activities to search for people, because thermal imagers will be able to track a missing person if he is near the area where searches are being conducted. That is, we can conclude that thermal imaging devices have found wide use not only in strategically important industries, but also in industries that the average person encounters every day.

How Is It Different Than Night Vision?

There are also night vision devices that are also used during various types of work. How do such devices differ from thermal imagers? First, this is the mechanism of operation of each of them. Yes, night vision devices allow you to see certain objects in the dark. However, thermal imaging devices are equipped with an additional heat indicator, that is, a source of infrared radiation, which allows not only to see something in the dark, but also to recognize this object. That is why thermal imaging cameras are used more in search operations or in military affairs. They help to recognize the heat that comes from a person and thus help to achieve the result that is planned by a certain activity. Also, the difference between these devices is their price. Yes, night vision devices are more affordable to purchase than devices equipped with thermal imaging mechanisms. This is primarily due to the use of more expensive materials to produce thermal imagers, as well as high technologies and intellectual activity embedded in their functionality. The purpose of using these devices is also different, so you need to clearly understand the purposes for which one or another device is needed. Also, if night vision devices are used and are useful only at night, then thermal imagers can be used both during the day and at night. In addition, thermal imagers function autonomously longer, which allows the user not to worry about the possibility of using it when the need arises.

Therefore, the evolution of inventions that greatly facilitate human activity in various fields is a significant step forward in all senses. Thermal imagers, as technologically complex and expensive devices, are useful not only for strategically important purposes and tasks, but are also widely used in such fields as law enforcement, medicine, search, and rescue, automotive, etc. This makes them attractive for purchase by ordinary users and helps in the implementation of the respective tasks for which they are purchased.