Sigma/Foveon Questions

Discussion in 'Digital Photography' started by Bubba, Apr 17, 2010.

  1. Consider printing a 3MP image at 10 x 8 inches, for example. You get
    print A. Now upsize the image to 12MP in your image processing software,
    and print it out again at 10 x 8 inches. Print B. Prints A and B are the
    same size, but the image has been increased in resolution in between. So
    an upsized image, but at the same size. "Size" can equally refer to the
    number of pixels as to the final print size.

    Cheers,
    David
     
    David J Taylor, Apr 28, 2010
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  2. David J Taylor, Apr 28, 2010
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  3. Bubba

    Ray Fischer Guest

    "No SIZE change need occur when you UPSIZE an image"
     
    Ray Fischer, Apr 28, 2010
  4. Bubba

    Ray Fischer Guest

     
    Ray Fischer, Apr 28, 2010
  5. Bubba

    Guest Guest

    upsizing doesn't add any detail so the resolution isn't going to be any
    different.
     
    Guest, Apr 28, 2010
  6. []
    Ray, rather reluctantly, as you appear unwilling to listen to what others
    are trying to explain to you, and as you persist in name calling rather
    than in reasoned argument, I will no longer engage in discussion with you
    on this topic.

    David
     
    David J Taylor, Apr 28, 2010
  7. Bubba

    Guest Guest

    the word pixel appears only once in the entire document and it says
    'image data' for 4 visible/near-infrared and 8 infrared channels, not
    pixels.

    it's a 13.7 megapixel sensor (3712 x 3712), with each pixel having 12
    components. it is *not* 165 megapixels.
     
    Guest, Apr 28, 2010
  8. I think that many people would see the difference between a straight 3MP
    image and an interpolated 12MP one, in a 10 x 8 inch print. Don't you?

    Cheers,
    David
     
    David J Taylor, Apr 28, 2010
  9. If you look at the physical sensor, there are (IIRC) three detectors for
    each of 11 channels, so does that make it a 33 pixel sensor?

    BTW: channel 12 actually has three times the resolution, and has 9
    detectors scanned.

    Where it differs from the Bayer sensor is that at each spatial location,
    11 different spectral bands are sensed. so that at each location there
    are 11 independent measurements. No interpolation involved. With the
    Bayer sensor there is only one measurement at each location, so in the
    12MP sensor, 3MP of red, 3MP of blue and 6MP of green, and yet in the
    final image there are 12MP of red, 12MP of green and 12MP of blue. These
    extra values are derived by spatial interpolation and other refinements.

    The SEVIRI more resembles the Foveon approach, but with far better
    filtering to separate the individual spectral components. For each
    channel, 3 detectors, and 3712 x 3712 pixels.

    Cheers,
    David
     
    David J Taylor, Apr 28, 2010
  10. Bubba

    Peter Guest


    You're wasting time trying to explain terms of art.
    He thinks a table of contents is a piece of furniture.
     
    Peter, Apr 28, 2010
  11. Bubba

    Guest Guest

    no. it might be slightly better than just letting the printer handle
    it, but do you really think there will be more detail in the upsized
    one?
     
    Guest, Apr 28, 2010
  12. Bubba

    Guest Guest

    no. fuji had a similar problem. if you had a single dot with a million
    layers or channels or whatever, would that be a megapixel sensor?
    that doesn't mean it has 11 times as many pixels.
    it may be a very accurate pixel, but it's still a *single* pixel and it
    differs from foveon because each measurement is independent.

    with foveon, the layers are tightly intertwined. unlike the pretty (and
    misleading) pictures in their ads, the layers do *not* measure red,
    green and blue, that's only a result of (here it comes), interpolation.
    in fact, there is more interpolation with foveon than there is with
    bayer which is comical, actually.
     
    Guest, Apr 28, 2010
  13. no. it might be slightly better than just letting the printer handle
    There is more apparent detail, but whether it is accurate or not is
    another matter. In satellite images we do find that providing a 2:1
    interpolation (e.g. from 3MP to 12MP) does make fine detail more easily
    discerned (than simple pixel replication).

    Cheers,
    David
     
    David J Taylor, Apr 28, 2010
  14. []
    Agreed.

    [Although I would prefer not use the term "interpolation" to describe the
    3 x 3 matrix processing to convert the three Foveon sensed values into
    three RGB values. Something like "colour correction", perhaps?]

    David
     
    David J Taylor, Apr 28, 2010
  15. Bubba

    Guest Guest

    well, it *is* interpolating the overlapping spectra to figure out the
    incident colour is (and not all that accurately either).
     
    Guest, Apr 28, 2010
  16. That's Ray's m.o. pretty much all the time. Moreover, he somehow feels
    it's "a good thing" to repeatedly call the angry pest an asshole while
    telling him to go away.
     
    John McWilliams, Apr 28, 2010
  17. Bubba

    Ray Fischer Guest

    I've presented the reasoned arguments. You refuse to listen.
    You haven't started. You've just be ferting your patently wrong crap.
    Now you're going to run away.
     
    Ray Fischer, Apr 28, 2010
  18. Bubba

    Ray Fischer Guest

    And you think it's fine to lie rather than deal with the facts.
     
    Ray Fischer, Apr 28, 2010
  19. Bubba

    Ray Fischer Guest

    Once again you confuse "pixel" with the data used to represent the
    pixel. Is a single RGB pixel really 24 pixels buecause it uses 24
    bits to represent the color? That seems to be your argument.
    Now explain why that is of any relevance at all.
     
    Ray Fischer, Apr 28, 2010
  20. Bubba

    Ray Fischer Guest

    Since the final image is the same size at the sensor then your statement
    cannot be true.
     
    Ray Fischer, Apr 28, 2010
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