thermal imaging

I have had an idea! If I can acquire a thermal imaging camera, I would show exactly where the hands of the person opening the door would be.

I'm beginning to think that they are far too expensive to buy so hiring one may be a better option of me.

However, with any luck, they'll be an iPhone app that does the same thing for a small cost and with any luck would be free.

I think that this would be amazing for what I want to look at. As well as it showing where the person has interacted with the door, it could also provide me with an interesting colour palette, ranging from blues and greens, right through to hot pinks, oranges and reds.