The Basics of Infrared Thermography
Infrared Thermography is a process in which a camera detects infrared energy emitted from objects, converts that information into a temperature and displays an image illustrating those temperatures. Infrared is a term that many might be familiar with, but do not fully grasp. We wanted to help people understand what infrared thermography is, how infrared cameras work, and various ways to use this technology.
What is Infrared?
To understand this, you need to know what electromagnetic energy is. Energy occurs in many forms, one of which comes from the rapid and constant movement of atoms. As these atoms move, they create electromagnetic energy in different wavelengths. Our eyes can detect a small range on this spectrum, visible light. This is how we perceive the color of objects. At the lower frequencies, there are radio waves and microwaves. In the higher frequencies, you get x-rays and gamma rays. Infrared refers to the range of frequencies on the electromagnetic spectrum just below the color red. Since the frequencies are too low, our eyes cannot see these waves. As an object heats the atoms that comprise the object move more rapidly. This increased movement increases the amount of infrared radiation emitted from that object. This makes detecting infrared waves among other uses a good indicator of how hot something is.
How an infrared camera works
So how does an infrared camera give us an image and temperature readings? Inside the camera is a detector that can measure the amount of infrared radiation coming from objects in front. Depending on the camera there will be a different number of measurement points each of these points correspond with a pixel displayed on the screen of the camera. The camera then displays the readings as a color assigned using the minimum and maximum readings on a color scale you choose in the camera settings. Since it displays the image on a relative scale, infrared cameras display temperature differences. It will display if the same color. It is good to understand that the camera does not measure temperature. The camera measures infrared radiation and converts that measurement into a temperature reading. This also means that the camera doesn’t use visual light to create the image, an infrared camera works in complete darkness.
Why do we want to see heat?
There are many reasons we would want to measure and visualize heat. First is in predictive and preventative situations. If you are working with equipment that has moving parts, it will produce heat because of the friction. As a piece of equipment ages, it deteriorates and becomes less efficient producing more heat. Because of this, you can use thermal imaging to monitor the health of equipment. This allows organizations to fix or replace equipment before it can break and disrupt production. Another reason can be quality control. In the creation of certain products, it needs uniform heat over a certain area. An infrared camera can identify cool spots that might affect the product. The most important reason is for safety. Firefighters will use infrared cameras to check if metals are hot and to see through smoke. Utilities also use infrared cameras before entering vaults or cabinets containing high voltage electrical systems. They do this to identify the risk of exposed live parts, loose connections or faulty insulation. This prevents preventing deadly incidents some examples would be grounding out or arc flashes.
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