FLIR has some cool toys. One of our clients sent us his crazy expensive FLIR unit that was HUGE, and required a laptop to run and 115 volts AC and about 6 minutes to "boot" because of the little cooling unit the sensor sat inside of. It used some fancy system to cool it to under -100 F and it was fantastically sensitive and B&W only. He had us flying over Cape Canaveral at night and all the lights were turned off on the ground. The two very experienced pilots hated ever second of flying in pitch black, knowing that the Atlantic ocean is pretty much endless to a Cessna 206.
This image is from a handheld 25 grand unit we used for a few jobs. The top image show me holding the camera, and the side of the head of my business partner. You can see the size of the camera in my hand. The bottom photo is shot at the same time and this is the view a human sees, just a stainless steel fridge and a hit of a reflection. If one walked across the room even wearing shoes it was clearly footprints in the thermal image.
I have wanted the phone version to play with but it is an expensive toy.