Infrared Camera

On the left is the lens housing from my cheapish RM50 Made-In-China webcam. I unscrewed the lens out, and took a knife to it.

In order to remove the small pinkish glass on the bottom. That's the InfraRed filter.

Then on the right, is a piece of fully exposed colour film negative. I cut a small circle of that out, and glued it to the lens, where I removed the IR filter.

Then put the lens back into the digital cam, and took the following picture.



That's my buffish fore arm. Under infrared, all the veins show up on the camera. Under normal lighting, none of those veins show through my well tanned complexion.

Theory of operation:

The electronic sensor in even a cheapish webcam is sensitive enough to pick up infrared light. Thus, an IR filter is put in to block some of the IR, or else the brightness will wash out the picture. When I pried out the IR filter, I let IR light back in. When I added a piece of exposed negative, that blocks out a lot of visible light. So now, the camera captures mostly IR light.

Why do I do this?

Cos I've got that kind of time in the office...