Recently my job sent me through a Level-1 Infrared (IR) Thermographer course. To demonstrate the fundamentals of IR, the instructor used examples of infrared used in veterinarian medicine. A collection of images were presented that were captured using an IR camera. These images clearly showed various types of tissue inflammation. Because flesh has a high emissivity, you are able to see heat patterns on the surface of the skin which are radiating from within the tissue. Unlike flesh, animal fur restricts the transfer of heat and therefore has a low emissivity. Due to the low emissivity of fur the images used horses as an example. This type of diagnostic tool is important when the patient is unable to communicate as to where the trouble is. Insert Mr. Ed joke here.

Now let’s jump to people. IR cameras were used during the tracking of the H1N1 virus. By adjusting the span and level of the camera, it is easy to pick someone out of a crowd of people that has a fever. The span filters IR waves that are below a set point, in this case a normal human temperature of 98–100 °F. The level adjusts the heat signature, in this example black and white will work best as opposed to the rainbow color palette that you may be familiar with. If someone is sitting in a football stadium or walking in a crowd through an airport with a body temperature of 103 °F, that person will show up as a bright gray blob in a sea of black phantoms.

Finally, I’m going to wrap this up by giving an example of how thermal imaging can help with the early detection of breast cancer. To start thing off I’m going to let a Ph.D. do the heavy lifting.

Angiogenesis, or new blood vessel formation, is necessary to sustain the growth of a tumor. Digital Infrared Imaging may be the first signal that such a possibility is developing (M. Gautherie, Ph.D.; Thermobiological Assessment of Benign and Malignant Breast Diseases. Am. J. Obstet. Gynecol., 1983; V 147, No. 8: 861-869)

The images, which can be found around the Web, are amazing. In some cases you can clearly see the network of blood vessels that will eventually feed the cancer cells. The detection of angiogenesis using IR can be years prior to any cancer actually appearing in the patient. Initially this detection was so early that doctors thought they were seeing false positives, when in fact the patients did ended up with breast cancer many years after that first diagnosis.

I just wanted to share. I went to a class to learn how to perform preventative maintenance inspections on low to medium voltage electrical equipment using an IR camera, and ended up learning a pile of interesting stuff.

And because this is after all the Defcon forums…

IR cameras cannot see through clothing. But depending on the emissivity of the fabric and the focus of the camera, one could see the heat pattern on the surface of the clothing that’s being radiated from underneath.

After a user types a PIN onto a PIN pad, one could look at the pad using an IR camera to capture the user’s PIN. This is old news but an update to this concept would be to view the swipe patterns on the screen of a smart phone. See Newton's Law of Cooling for further details.

-rkill