This app is a realtime thermal camera effect that simulates a infrared camera.
Have fun with the Thermal Camera. Prank your friends and tell them your phone can detect heat !!
The quality of the images depends of your mobile photographic camera (lens,objetive, CCD, resolution, ISO sensibility...)
This app is only a simulation of thermal camera and it will not detect a real temperature.
Android phones don't have built-in infrared light sensor or thermal sensor, so they are unable to detect what is hot and what is cold.