The original post: /r/explainlikeimfive by /u/MCA1910 on 2024-07-23 04:15:13.

I’m a firefighter and we just bought new TICs (Thermal Imaging Cameras). We did a training to familiarize ourselves with the new equipment and simulated searching for people in the station gym. While using it, I noticed that the display would show a silhouette of my body in the mirror. The way these cameras work (as I understand it) is not to look for an image to repeat on a screen, but to look for heat. I understand that my body gives off heat, and that’s how it distinguishes people for the image. However, the “me” in the mirror isn’t me. It’s only a reflection. So, shouldn’t the camera just show no heat coming off the wall/mirror?