Nikon - CCD tricks with mirrors.

Discussion in 'Nikon' started by frederick, Aug 9, 2007.

  1. frederick

    frederick Guest

    This has been posted on DPReview.

    Interesting comments:
    "According to the second embodiment, as in the case of the first
    embodiment, since the red, blue, and green light passes through the same
    opening, the photon utilization efficiency of the light receiving
    element can be increased. In addition, the red, blue, and green light is
    in the same spatial position, so that false color does not appear."

    So, although photosite size is probably small, this is (at least
    partially) offset by not losing light through rgb filters. Patent was
    applied for in 2003.

    Canon also proposed a more conventional "foveon" type sensor in about
    2000, but it hasn't eventuated in a (Canon) camera yet.
    frederick, Aug 9, 2007
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  2. frederick

    Paul Furman Guest

    Reading the patent is an awkward way to figure out what they are talking
    about, has someone written an article about this thing in plain language?

    Also quicktime doesn't load the drawings properly, it would be helpful
    to see wtf this is.

    One thing I noticed is they talk about this Nikon invention being used
    in video cameras to avoid bayer filters not still cameras so I'm not
    sure it's relevant to still photography. I seem to recall this has been
    implemented in video cameras, though I'm certainly not sure, maybe that
    was something else.
    Paul Furman, Aug 10, 2007
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  3. frederick

    frederick Guest

    There's some comment on and a link to drawing on DPreview site.
    I think that the reference to video cameras was referring to use of 3CCD
    systems on video cameras. I haven't gone back and re-read the patent
    info but IIRC it refers to it as a related technology.
    frederick, Aug 10, 2007
  4. frederick

    acl Guest

    acl, Aug 10, 2007
  5. frederick

    Paul Furman Guest

    Ah, OK, I get it. If that's an accurate diagram, it's an awful lot of
    empty silicon & awfully small pixels. I don't think it has any
    application in DSLRs.
    3CCD, ah there's a name I can search with!
    "Three-CCD cameras are generally more expensive than single-CCD cameras
    because they require three times as many elements to form the image
    detector, and because they require a precision color-separation
    beam-splitter optical assembly."

    This looks like a variation on that concept with mirrors instead of a
    prism. That link links to a Canon 3CCD camcorder for pro use (expensive).


    "The Canon GL2 has three CCDs, delivering outstanding picture quality,
    highly accurate color reproduction and a wide dynamic range with
    virtually no color noise. On top of that, Canon has improved a broadcast
    technology to create a new form of Pixel Shift, producing greater
    picture quality than that of camcorders using CCDs with almost twice the
    number of pixels.

    Pixel Shift
    In the GL2, Canon uses Pixel Shift, a signal processing method used in
    broadcast TV cameras, to exceed the overall picture quality achieved by
    camcorders using nearly twice as many pixels.

    With the light coming into the camcorder split into three color
    components, each of the three CCDs then handles one of three primary
    colors: Red, Green and Blue. The green component of a video signal
    contains 60% of the picture detail, and the red and blue components only
    40%. The green CCD in the GL2 is shifted the equivalent distance of 1/2
    pixel from the red and blue CCD. The green signal is then sampled more
    frequently to extract the maximum picture detail from the video signal.

    In addition to outstanding clarity and natural color, Pixel Shift
    provides wider dynamic range, reduced vertical smear from bright light
    sources and sharper still images.

    Super High Resolution and Super Low Light

    There are 410,000 pixels on each of the three CCD image sensors in the
    GL2. With the new Pixel Shift technology, the GL2 rivals the resolution
    of camcorders using CCDs with 680,000 pixels."
    Paul Furman, Aug 10, 2007
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