

Bill’s back! I am pleased beyond measure to present the first video in Engineer Guy Series #4, in which Bill Hammack and his Engineer Guy production team at the University of Illinois unravel the key technology of digital photography: the charge-coupled device. Most of you will probably have a sense of the CCD as a grid of very many, very tiny semiconductor sensors, each of which corresponds to a single pixel in a raster digital photograph. That’s essentially correct. But my intuition, at least, of the more subtle engineering aspects—How does the camera read information off the grid? How does it detect color?—turned out to be dead wrong on both counts. Watch the video, now, and you too may be delightfully surprised, and in any case delighted. Bill’s work is always a pleasure to behold, even if you already know this stuff. Or think you do. [Thanks, Bill!]

Sean Michael Ragan




  1. ChrisW says:

    A good introduction to CCD imagers. There are alternatives to the RGB mosaic filters. Foveon makes an MOS sensor with co-sited pixels. They are stacked on top of each other. The shorter wavelengths (blue) excite the first layer. Greens excite the middle layer. Reds excite the bottom layer.
    Many new professional video cameras still use three sensors with an RGB splitting prism.

    1. Indeed! There are a lot of these CFA (color filter arrays). We showed the Bayer Filter which is pretty common. While I said it works pretty well – and it does – if you search around on the web you’ll find fascinating articles that pictorial shows some of the issues with CFAs ….

  2. Jack S. says:

    Wait, how does the CCD shift the charges from row to row without wires?

  3. Ces says:

    Very instructive, but how much better would it be without the incessant music. If I attended a course or lecture would there be any music? No!

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