Thermal imaging... Just a few years ago, this infrared imaging technology cost tens of thousands of dollars for a low-end device. Now it's available as a teensy add-on to an iPhone or Android, for a couple hundred dollars. After some quick testing around the house, I can tell you that it works as least as well as those military-grade devices the last time I saw one of them in action. I haven't seen it in low light level situations yet (we'll try it tonight), but it looks very promising. Here are three shots I took around the house:
The first one shows Miki, watching Debbie eat her lunch (and hoping for some of it to drop down within his range). Note how his head – and especially his eyes – glow brightly. Those are the areas where his body is losing the most heat.
The middle photo is of our kitchen table top, without my hand in the photo. I made this by placing my left hand on the table top, counting to five, then taking my hand away and snapping the photo. The infrared camera is sensing the very slight temperature difference caused by my hand's presence a few seconds before I took the photo. My hand's image was still clearly present 20 seconds later, then rapidly faded away.
The last photo is a closeup of Miki's head (still sitting, waiting hopefully). The resolution isn't even close to the visible light camera, but it's plenty good enough to discern what you're seeing.
I'm looking forward to trying this tonight, to see if we can spot some wildlife...