Infrared and the Narcissus Effect

• When recording an image with an infrared camera, stray reflections and temperature variations can cause distortions in the image. A reflection from a window, internal lens surface or other reflective object can result in the camera detecting and recording its own image. The result is either a dark (cold) spot or a bright (warm) spot on the image, depending upon how the camera detects the temperature of the object it captures. The narcissus effect can be eliminated by changing the viewing angle so that there is no stray reflection, by using antireflective coatings on optical elements and by ensuring that any internal reflective surface is out of focus and not detected by the camera.