Single Pixel Camera

I was on the bleeding edge of digital photography when I bought my one megapixel camera back in ’96. Now some physicists at Rice University in Houston have the nerve to build a ONE PIXEL camera. The camera produces images by recording thousands of single-pixel images one after the other, rather than simultaneously recording millions of pixels.

It’s not the greatest camera in the world, as you can tell from the pictures you see here. The image on the left is a conventional close up photo of a Mandrill and the photo on the right is a single pixel camera shot of the same image. What’s more, it takes about fifteen minutes to record a shot like this with a single pixel. So it’s not likely that you’ll be standing in line at Circuit City with a single pixel camera in your cart any time soon.

The key benefit of the experimental camera is that it needs much less information to assemble an image. Massive CCD arrays collect millions of pixels worth of data, which are typically compressed to keep file sizes manageable. It’s an approach the Rice researchers describe as “acquire first, ask questions later.” Many pictures, however, have portions that contain relatively little information, such as a clear blue sky or a snowy white background. Conventional cameras record every pixel and later eliminate redundancy with compression algorithms.

The single pixel camera, on the other hand, compresses the image data via its hardware before the pixels are recorded. As a result, it’s able to capture an image with only thousands of pieces of information rather than millions.

The compression is achieved with an array of tiny, movable mirrors. Various mirror arrangements encode information about the photographic subject as a whole, in lieu of the point-by-point image recording in a normal camera.

One potential payoff of this sort of research is that it may make conventional digital cameras much better. If a single pixel can do the job of an array of pixels, as the Rice University team shows, then you could potentially get each of the pixels in a megapixel camera to do extra duty as well. Effectively, you can multiply the resolution of your camera with the techniques developed in a single pixel camera.

The technology could make cameras much cheaper by letting us get by with fewer pixels, or perhaps lead (some day) to gigapixel resolution from megapixel cameras. In addition, the researchers say, the single pixel detector can be replaced with devices that register other wavelengths of light, potentially leading to images collected with light outside the ranges that CCD and CMOS detectors can handle.

You can peruse the paper that the researchers presented at the Optical Society of America meeting a few weeks ago in Rochester, New York, if you want all the details. For more readable information, visit their website or read the Physics News Update item my friends at AIP posted recently.

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