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Video Processing

Discussion in 'Electronic Design' started by Tom, Aug 11, 2005.

  1. Tom

    Tom Guest

    Can anyone suggest a good cheap video processor IC that will take an input
    from a CCD camera and then store a signle shot to RAM. It doesn't need to
    compress the data or have a continuous feed as the system will mostly be
    used to take an optical sample every second or so for analysis. However, it
    would be nice if it could store the image in under a ms or so and then I can
    read it out for display by an LCD controller to give an occasional live
    feed.

    AdvThanksAnce

    Tom
     
  2. The majority of framegrabbers use the BT878 from Conexant.
     
  3. Tom

    Tom Guest

    I looked at Conexant's Website and they don't mention the BT878 but I've had
    a look at the BT829B and it looks to be in the region of what I'm looking
    for. However, I'm still quite new to video and I'm wondering how to store
    the Y/C data in RAM as an RGB bitmap. I suspect that an FPGA or CPLD is
    going to be required or are there devices available which will take care of
    everything for me?
     
  4. I suppose you have to translate Y/C to RGB if you want to display
    it. But that is just software ;) I agree, these chips are not trivial
    stuff to implement. Perhaps using a full digital CCD camera is
    easier to connect. Or look for frame buffers used in 100Hz TV sets.
    I don't think there is a converter chip that looks like an ordinary
    static ram chip with just address and data lines, that would be ideal
    of cource.
     
  5. Tom

    Tom Guest

    It's encouraging that Y/C to RGB is just software because I don't reckon it
    would be a huge problem to buffer streaming pixel data (famous last words).
    Do you know what the conversion process is?
     
  6. I'd suggest the ADI BlackFin. It's small, low-power, and cheap. You
    will however need an external PLD or otherwise to generate the CCD
    control signals. At least you would with any CCD I've used.

    If you need any help developing with the BlackFin let me know.

    Cheers,

    James.
     
  7. They take a group of 4 pixels and store luminance for all pixels, but
    for the color information R-Y and B-Y only twice per group of 4 pixels,
    or only once per group of 4 pixels. It's named YUV 4:2:2 or 4:1:1. Or
    something like that.

    To restore to 24 bit RGB, you have to add/subtract and multiply a
    lot, with crazy factors I don't remember. But you can use lookup tables
    to speed things up.
     
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