How Does a Thermal Camera Detect Temperature?
If you’ve ever tried out the thermal camera on your phone or used a professional one, you know how fun they are to play around with. However, they are just as useful as they are fun. Did you know that many industries use them? From detecting fevers in viral outbreaks to finding problems in plumbing, thermal cameras detect what we cannot see with the naked eye.
How Does a Thermal Camera Work?
Basically what a thermal camera does is detect changes in temperature. Whether it be a thermal imaging camera or a body temperature measurement camera. They do this by detecting a type of light we cannot see ourselves — infrared (IR). To better understand this, we need to know how this light is in nature.
When the sun shines on the earth, it does so at different levels of light. The only level that humans see with their eyes is visible light. The rest can only be detected by special devices, such as the thermal camera. Some examples of this invisible light are x-rays, gamma rays, ultraviolet light, and more.
So what is it that thermal cameras can do that we can’t? Well, all objects — whether human or inanimate — give off infrared light. But we can’t see this. Although, in some cases, we can feel it as heat; like when a person has a fever. Thermal cameras come equipped with a special sensor that can specifically detect IR light or wavelengths. Normal cameras don’t have this feature. They can only detect visible wavelengths — the same things we can see with our eyes. In an IR camera, you can determine the intensity of the light by the colors that you see in a thermal image. Orange to red images is cold. White to blue images are hotter. Some thermal cameras can even show a temperature reading!
Types of Thermal Cameras
Thermal imaging cameras come in only two types. Cooled thermal imaging and uncooled thermal imaging cameras. The only difference is the range at which they work and how they perform their function.
A cooled thermal imaging camera comes built with a cryocooler. The cryocooler reduces the thermal noise to form an image. In simpler words, the cooler helps detect images from a medium to long distance. They can detect thermal images from 5km all the way up to 16km. The cryocooler also makes the camera very sensitive. This allows for better results and can even compare the contrast between temperatures. To add, a cooled thermal imaging camera is ideal for mechanical locations, as they have a high tolerance for these environments.
An uncooled thermal camera is ideal for short-range — less than a kilometer. It does not come equipped with a cryocooler, hence the name. So, it only works at room temperature and is a lot quicker and less fussy to use. It’s also a more cost-effective option.
At first glance, uncooled cameras sound like the way to go, but it depends on what you need them for. Unless you are completely sure of your requirements, this decision can prove to be a difficult task.
The Body Temperature Measurement Camera
A body temperature measurement camera is used to detect fevers in times of medical emergencies, just like one we are in now. They are installed in hospitals, airports, schools, offices, and wherever detection is needed for multiple people at once. However, can they detect a fever or a virus? The correct answer would be no. But it’s important to know how they help with the situation.
The first thing to understand is that a body temperature measurement camera can only detect surface temperature. And your surface temperature can change for many reasons. Could it be a fever? Yes, absolutely. But it could also be another medical condition or that it’s only a hot day. But the body temperature measurement camera already does something that one person can’t detect in multiple people at once — their temperature. One benefit is that it greatly reduces the workload. This way, it also makes it safer for users as it’s touch-free and low-maintenance. To add, it can rule out people from a crowd that has an elevated temperature than others. This makes it easier for us to know whom to look out for.
Even though it only detects surface temperatures, there are some key areas to view on the body that may suggest a fever. If a body temperature measurement camera shows elevated temperature in the upper part of the face, that individual should be further tested. The main spots to look out for are the corners of the eyes and the forehead.
The Thermal Imaging Camera
The body temperature measurement camera is just one way that a thermal imaging camera can work. But it also has other uses. For example, thermal imaging is used in agriculture to determine the temperature of crops. It’s used in plumbing to solve irrigation and other issues. Thermal imaging cameras are also used for home security, especially for night vision.
Night vision technology is incredibly important for security. Since normal cameras only see what you see, at night they can be inefficient if someone or something is sneaky enough. However, with a thermal imaging camera, you can easily tell when there’s an intruder. Remember how they can sense heat? This makes the task of finding an intruder a lot more simple. Cold-blooded creatures such as animals and humans are easy to see. They will record in a different light than their environment. This way, you can avoid false alarms and “see” past your visual limitations.
The best part about thermal imaging is that it’s super effective and helpful in situations you cannot control. Security is a top concern for many people in many industries, and this is one of those tools that make their job easier. Not only that, but thermal imaging cameras have become part of doing their jobs itself.
Summing Up
Regular cameras depend on light and reflection to produce images. But what most people don’t realize is that you need to have an image contrast. This is an important factor that directly affects what you do or don’t see. For example, a white figure standing in a dark background is a lot easier to see than a dark figure in a dark background. Just like humans, traditional cameras have limits on what they see. Thermal imaging cameras and body temperature measurement cameras do not have these flaws. First of all, they use heat to detect objects instead of light. And everything in our life has a heat signature. This factor makes them stand out when we see it in a thermal image. So, it’s better to rely on a result produced from thermal imaging than the one you can see with your own eyes or a regular camera.
