Even the most sophisticated cameras can’t compete with a thermal camera. Therefore, understanding the thermogram-producing device’s fundamentals is critical to unlocking its mysteries. And to find out if the nifty device is able to see through walls. Even further. One thing is for sure. The thermal imaging device has, without a doubt, produced groundbreaking results ever since its inception. It was initially utilized in the U.S. military (e.g., Korean War), law enforcement, and later in firefighting in 20th-century America.
It seems odd that a thermal camera with such impressive credentials would be used to see through walls. Home inspectors worth their salt would tremble in joy at such a fantastic ability. But is it possible?
There is one big question. Infrared’s unique properties provide us with the answer. Understanding the behavior of infrared light is essential to unlocking thermography’s potential.
Let’s get started. We use the word ‘see’ to refer to our eyes’ ability to view the world around us—for example, the mountains and leaves. Generally, old-fashioned cameras give us an exact – if not better – depiction of our surroundings. It’s a world of light-dependent creatures.
However, thermal cameras do not work this way. They see differently from our eyes. Heat signatures – individualized heat signals – are instead detected around the sensor. As a result, when you look at a thermograph, the picture produced by thermal imaging, you see various colors representing the thermal energy within the scene.
The thermal camera sees the scene differently than a normal camera would. An object’s heat value is used to define it in its world. The temperature can only be measured if heat bounces off an object directly in front of it.
Thermal cameras detect the heat reflected off a wall when scanning it. A perpendicular wall’s surface temperature changes when scanned. As a result, if something so hot, like fire, is behind that wall, the heat from the fire will be reflected on it. This will be visible to the thermal camera. As a result of that fire, a thermograph would show heat.
Specifically, infrared can detect only the heat signature of a surface. In response to this layman’s question, the answer is no. This is only due to the fact that the question is framed from the POV (point of view) of someone who would observe as a human would.
Although we can’t see through walls with the thermal camera, we can at least say that it can detect heat. Once again, here we are referring to the fact that heat is thermography’s language. We don’t look for the beautiful scenery in a traditional photograph.
Does infrared radiation not penetrate walls as X-ray vision does?
It is important to consider the range of thermal imaging systems as well. Not all thermal imaging cameras are created equal. The same is true for traditional cameras.
Commercially available thermal imaging cameras generally function in two ways:
In the electromagnetic spectrum, we are talking about wavelengths between 3µm and 14µm. The MWIR spectrum has wavelengths of 3 to 5µm, while the LWIR spectrum has wavelengths of 8 to 14µm. As a result, the planet’s heat is emitted in these ranges by most, if not all, objects.
As it gets hotter, an object is more likely to emit electromagnetic radiation, usually referred to as EM.
However, walls serve to block the wavelengths of these electromagnetic waves. As such, when you point a thermal camera at a nearby wall, the device measures the heat emissions that are given off by that wall. It does not measure the heat emissions from behind the wall.
When the heat affects the wall, you may be able to see its heat signature when that heat is affecting that wall.
The same analogy can be applied to glass, which will not register on a thermal camera. It’s simply because glass, especially most of those we come into contact with on a daily basis, transmits heat below 3µm wavelength. A range that is way below a standard thermal camera’s normal range.
Also known as black-body radiation, thermal radiation occurs within or around a body. A thermodynamic equilibrium refers to an object’s relationship with its environment.
Is it possible to see through walls using thermal imaging? This depends on what kind of image you want. It’s a matter of perspective. To produce a picture of the objects behind that wall, the type of picture you keep on your smartphone as a memory, that would be a NO.
However, it is important to note that infrared cameras see only heat signatures. A normal camera sees the light. Therefore, rephrasing the question to: Can a thermal imaging camera see the heat behind a wall? I believe it’s absolutely possible. Heat signatures can affect a particular wall’s surface temperature as long as they’re strong enough.
The above proves how thermal cameras have impacted our everyday lives – regardless of whether there is a wall or not.