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Thermal Imaging Basics: 5 Critical Components of The Thermal Imaging Camera


George McNeil, BS, NR-P, LP, ISO

Captain Andy Starnes, AAS, FI-2, FO-3, NC-EMT

Technology is ever changing in the world today and the fire service is no exception. Since the late 90’s the Thermal Imager has emerged on the fire ground as a great tool. Like most tools that we use today it is often only as good as the person using it. And the person using it is only as good as the training they received. So let us ask ourselves: how much training have we really received on thermal imaging cameras?

A point to consider is this: If we lack experience with a TIC or lack experience and knowledge in firefighting; should we be interpreting the data on the TIC?

Thus inexperienced firefighters or those who lack experience with a thermal imager should not be the in charge of the TIC at the scene of a working

fire due simply to lack of experience and training.

Once a firefighter has been through a hands on class and worked with a camera in an IDLH environment then they can start using the TIC on fire calls. TIC training should be conducted in smoke conditions so the user will be used to the challenges of reading a TIC in an IDLH environment. This allows the firefighter to understand and interpret the images in the real world versus the classroom.

The next few tactical tips articles are going to focus on the the basics of thermal imaging. We are going to discuss how they are built; when and how to use them leading up to tactical TIC use on the fire ground.

Every camera on the market from the top of the line to the inexpensive camera’s all

have the same five components that work together to render infrared radiation in a visual display.

What are these components? The eyes, the nose, the brain, the mouth

1. Optic System-This can be compared to the eyes of the TIC.

The first part of the thermal imaging camera is the optic system. When you point a camera at a heat source the optic system picks the heat and infrared radiation and starts the rendering process to display. We need to be aware that our normal range of vision (Field of View) with our eyes is 270 degrees but with a TIC it will vary between 37-55 degrees Field of View. We also need to be aware that the optic system is going to be very prone to getting covered up with smoke and soot which will affect the TIC’s ability to accurately read the temperatures around us. As we work our way through the building and we wipe our face piece off we should take our finger and wipe the optics off. Also consider, keeping the charging points clean after use will help to insure it charges properly.

2. Detector: The second part of the camera is the detector. This can be compared to the nose of the TIC. The detector is what detects the heat signal from the infrared radiation signal that the optic system is picking up. This is the most critical part of the camera. There are two types of detectors: cooled and uncooled. Firefighting cameras are typically uncooled sensors due to they require less maintenance and cost less. Once it picks up a heat signal it will send that signal on to the third part of the camera.

3. Amplifier-The third part of the camera is the amplifierThis can be compared to the ears of the TIC. It takes the signal that has been received, detected, and it is strengthened. The signal amplifier takes the heat signal that optic system and detector picked up and amplifies it. Amplifying the signal makes it easier the end user to be able to differentiate between certain heat signatures.

4. Signal processing-This can be compared to our brain. How well do we understand and assimilate the information that we are seeing? The fourth part of the camera is where the signal is processed before the end user sees the visual display. This is made-up of a small computer it takes the data it receives and turns it to the display for the end user. Different cameras on the market will process the data at different speeds so you need to insure that your speed and abilities don’t exceed the thermal imager’s capabilities.

5: Display-This is the face of the camera. Our reactions are displayed upon our face and the ultimate picture is displayed on the display screen of the TIC. The end part of the thermal imaging camera is the visual display. When you raise the camera up and look at the screen you are seeing a visual representation of infrared radiation on the screen. The size of the screen makes a difference. Smaller screens, even with higher solutions, can be a deficit to the end user due to the smaller objects may be even more difficult to recognize such as a small child’s hand. The greater the resolution the better the image quality. The user needs to be aware that image quality can make a significant difference in locating victims and reading the thermal environment correctly.

We have discussed the five critical components of the TIC but in the next series we will discuss how we interpret the data on the display by understanding five more key attributes of the TIC. These key attributes or features are modes, field of view, resolution, distance to spot ratio, and color palette.