Saturday, 20 June 2009

Progress with Invisible White Light

The story so far...

I needed to get some measurements on the response of my camera to invisible light radiation. Here I took a photo of myself (in a mirror) illuminated by ultraviolet light. I could not actually see the light myself but the camera could, as you may see. If you grab a sample of my face and run it through a colour histogram tool (e.g. in PaintShop Pro) you will see that red and blue are very much in evidence and green scarcely at all (the tiny amount of green present is due to ambient light interference - I really should have done this experiment in the dark). So there you have it. That's what I call Ultra Magenta - the red and blue sensors in the imaging chip responding inappropriately but usefully to ultra violet light.

That's the red and blue sorted out. What about the green? That's where I need to infill with the infra red, which looks green to the camera.

I have tried but I cannot illuminate my face sufficiently using even a score of old TV remote control handsets. Here's the solution:
A large array of IR LEDs. Got to get it working first. Watch this space...

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