Explorations in the Infrared Spectrum

Me in false color IR
Me in false color IR

Okay, okay, this one is a bit geeky, but it’s fun so I had to try it. I don’t remember how I found this, but I saw somewhere that you can easily turn your $10 webcam into an infrared camera. Since I never ventured into the infrared spectrum with my film-based camera, this sounded like a great way to expand my photographic capabilities – at a rather low resolution, though.

Instead of lengthy instructions (which you can find here), I’ll just give you a short rundown on how to do this and leave you up to trying this for yourself. Here are the steps:

  1. Get a webcam. I believe anyone will do but I have found that the ball-shaped ones might be easier to work with than others due to their simplicity.
  2. Take it apart and look for the CCD chip. This is where the image gets acquired, so it’ll usually be in the center of the circuit board below the lens. (If you have a ball-shaped cam, then skip this step since you likely have a filter that’s attached to the underside of the lens, which screws out easily)
  3. Either below the lens or above the CCD chip is a glass plate that is coated with an IR-blocker. You need to get rid of that one. Either pry it out entirely or scratch off the coating. Try not to scratch the lens.
  4. Reassemble the camera and reconnect to your computer. At this point, you should see an image with colors that resemble the color shift you get with an old slide. You are now seeing visible and IR combined.
  5. Should have told you this earlier, but you need at this point an IR filter that blocks out visible light. Two ways to get one: 1) Take the blackened end of a color negative film and cut it to size to cover the lens on the outside or the inside. 2) Order a quite inexpensive (and more precise) plastic filter. I got mine from B&H Photo.
  6. Connect the camera and look at the incoming images. All visible light is now filtered out and you see infrared only.

The result is an image like this one:

pix_111934
Tree

Unfortunately the resolution and image quality is limited by what your camera can do, which is usually not much in terms of pixels and lens quality. If you need better quality, then feel free to modify your digital SLR (or video camera) in a similar (but more expensive) fashion.

Below is some of the fun you can have with this now. Be forewarned, this is not a thermal imaging camera – at least not for common household temperatures. The camera will, though, pick up heat above roughly 1400 degrees C (since the upper cutoff of these cameras is typically at a wavelength of 1700 nm). Check your oven heater coils for an example of this.

(click any image for a description)

It gets a bit more technical when we apply false colors to the video. This allows to distinguish a bit better between slight variations. In the example below, an inverted HSB scale was mapped to the black-and-white image:

False color lamp comparison
False color lamp comparison

And here is a video of another light source – a Christmas light chain:

The video above was made (video acquisition and color conversion) and captured using a small piece of software I wrote in processing.

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