When using an infrared camera, how can you identify hot reflections from spotlight sources?

• A. Use a Narrow Band Filter
• B. Increase Exposure Time
• C. Widen the Field of View
• D. Change the Viewing Angle

Answer: (D)

Hot reflections come from specular bounce of the spotlight off a surface, not from the surface’s actual heat. The key idea is that reflections depend on the viewing angle while true surface heat is tied to the material at that spot. By changing the viewing angle, you’ll see the bright spot move, disappear, or change intensity if it’s a reflection. If the hotspot stays in the same place with a similar temperature reading regardless of angle, that indicates a real temperature rise, not a reflection.

The other options don’t reliably distinguish reflections from heat. A narrow band filter might reduce some unwanted light but won’t consistently separate a broadband reflection from genuine emission. Increasing exposure time can wash out or saturate the image without clarifying the cause. Widening the field of view doesn’t test the directional nature of reflections and can just add more information without resolving whether the spot is reflective or actual heat.