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Can thermal imaging see through concrete?

Can Thermal Imaging see through concrete? The short answer to this question is, unfortunately no. This is so because thermal imaging relies on detecting the infrared wavelengths and temperature that is emitted from the surface of the object itself. The thermal imaging devices cannot see through thicker objects like concrete for example. Let’s dig deeper into this question and find out exactly why this is so.

To understand why a thermal imaging device cannot see through concrete, how exactly does a thermal imaging device work?

First and foremost, thermal imaging devices have a lens that focus the infrared light that is emitted from all objects in its view. The focused light that is detected by the lens is scanned by a specific phased array of infrared-detector elements. Those detector elements create a very detailed temperature-based picture which is also known as a thermogram.

Example of thermogram

It actually takes about one-thirtieth of a second for this detector to obtain enough information for the certain object and its temperature to deliver it to the user and make up this thermogram.

This further thermogram is created by the detector elements while it further translated into electric impulses. After that, those impulses are sent to a unit that processes those signals or impulses into data for the display.  The signal-obtaining unit sends the information to this display, where it is delivered to the user of the device under different colors depending on the intensity of the infrared emission. The synchronized combination of all those impulses from the elements are what creates the image.

Most thermal-imaging devices scan at a specific rate of 30 times/ second. They can sense temperatures starting from -20 degrees Celsius up to 2,000 degrees Celsius and can usually detect changes in temperature of about 0.2 degrees Celsius. With all that information taken into consideration, the thermal imaging devices obtain the said information from the surface of an object, living or not. Any obstacle between the object and the thermal imaging device makes it impossible for the device to make a proper reading. Thermal imaging devices cannot get past thick obstacles like concrete.

What thermal imaging devices can actually do although and what makes some people think that thermal imaging devices can possibly see through walls and concrete is to see how objects under the surface of specific items affect this item’s temperature. For a quick example, if you take a look at an indoor wall with a thermal camera, you can sometimes see where the studs are located. This is not possible because the thermal imaging device sees through the wall, but more or so because the studs are at a much different temperature than the air in the house or the insulation between them and this has a great effect on the detection of the surface of the temperature of the wall itself.

There are actually a few materials and visible obstructions that thermal imaging devices can see through although. Since thermal imaging devices rely on detecting infrared wavelengths and temperature, just think about a case where you would be able to feel heat from the other side of that wanted object. For example, if you had a campfire and put a wall in between yourself and that campfire, it would block the heat. But to some extent, this heat will be absorbed by the wall and this way the thermal imaging device will pick up the heat in the wall that is actually absorbed from the fire.

Example of headed wall in a house

So you are basically seeing the absorbed heat that is in the wall rather than seeing the temperature of the fire itself.

You will be amazed about those 25 Unbelievable Myths about Thermal Technology.

Related questions

  1. Can thermal cameras see through glass? – The detectors that are used in thermal imaging cameras receive any information and energy waves that directly come from the surface of different objects.  This means that a thermal imaging device cannot get past a surface like glass to get the information needed from the object that is beyond that glass, in order to deliver a thermographic image.
  2. Can Infrared Cameras see through fog? – Although thermal imaging cameras can see in complete darkness, different heaviness of fog, rain and snow narrow down the distance and lowers the ability for how far an infrared camera can see. The performance of an infrared camera is greatly affected under those conditions. Even in clear skies, different atmospheric absorption places limit out the possibilities of infrared cameras and how far the infrared camera can possibly see.

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