Eyes Resolution & Monitor Pixel Size

Discussion in 'Digital Photography' started by Hughes, May 6, 2009.

  1. Hughes

    Hughes Guest


    I wonder if this is just a coincidence or design.

    Human eyes have a average resolution of 60 arcseconds for brightly
    illuminated target.

    My monitor has a pixel pitch of 0.264mm.
    When I view it at a distance of of 800mm (0.8 mtr). The 0.264mm pixel
    subtends at an angle of
    theta = 2 arctan (0.5 (0.264)/800) * 206265
    = 68.07 arcsec

    The angle of the pixel subtended at a viewing
    distance of 0.8 mtrs is 68 arcseconds close to
    human eyes resolution of 60 arcseconds. Is this
    just a coincidence or did they make the pixel
    size of the monitor to match the resolution
    specification of human eyes by design?

    Hughes, May 6, 2009
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  2. Hughes

    Ray Fischer Guest

    Higher resolution is expensive. It makes sense that people would a
    monitor that is as sharp as they can see but not more expensive than

    Evolution in action.
    Ray Fischer, May 6, 2009
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  3. Hughes

    whisky-dave Guest

    Not all monitors are the same.
    I view mine at about 500mm

    The 0.264mm pixel
    If you take your 800mm that's 31.49 inches.
    That's about 10 times pi . but so what.

    What makes you think 800mm has any meaning.
    If such a meaning was meant surely they'd set distance of 1 metre
    a true SI unit.
    Playing with numbers can prove anything, i.e Captain Kirk caused 911

    Well the numbers in 1701 add up to 9 the first and last are 1s 911
    The word Enterprise has 9 letters, and there's 11 in captain Kirk . 911

    Coincidence well some don't think so, but they are, or should be
    in specially padded homes and kept away from sharp objects ;-)
    whisky-dave, May 6, 2009
  4. Hughes

    mcescher Guest

    mmmmm, pi......
    mcescher, May 6, 2009
  5. Hughes

    Don Stauffer Guest

    If the monitor were designed for one specific application then it may be
    design. But for a general purpose monitor, it is somewhat a combination
    of coincidence and design.

    Say I were designing a cockpit display for a military aircraft with a
    night vision device such as a flir. Then the acuity of the operator
    WOULD be a design factor.

    However, for general commercial monitors there would be some effort to
    determine what normal viewing distances are, and to avoid too high a
    resolution that goes beyond the viewers acuity, but that would not be
    the main driver. More to the point would be a cost-quality tradeoff.

    In essence, many years ago, monitor resolution did not match- one could
    see the pixels plainly. As TV and monitor business grew and involved
    more money, there was a big effort to improve resolution, and of course
    in TV systems the advent of HD standards. Eventually the performance
    equaled or exceeded the needs based on acuity, and there is no longer
    such a push for finer and finer ppi. Rather, the other factors,
    brightness, contrast and color purity are now the big efforts.
    Don Stauffer, May 6, 2009
  6. Hughes

    Hughes Guest

    This may be why they say there is not much difference
    in watching 720P vs 1080P HDTV shows at home at a normal sitting
    distance because the 1080P pixels and
    their separations are so small that our eyes 60 arcsecond resolution
    can no longer detect them (maybe needing 20 arcsecond to see the
    pixels separations). So there may
    be no need for 2160P HDTV years from now unless
    people get to see TV the same distance as viewing

    Hughes, May 6, 2009
  7. Hughes

    Chris.Bee Guest

    History records that the flat screen computer monitor is merely a
    development of the common CRT TV from the infancy of computers. (ZX81
    and BBC and vast rooms full of (mostly) white coated men using punched
    card sorters and giant reels of tape)

    It is quite amusing now to see science fiction programmes and films
    displaying large numbers of B&W CRT screens in "futuristic" space
    ships. If each new generation's tools and toys are magic to the
    last.. what do we have in store in the next?

    I wonder whether there will ever be a general move towards displays
    attached to the head itself? I doubt that "special glasses" will take
    off. Too many negative social aspects. Perhaps a direct connection to
    the optic nerve or the brain itself by some means of inductance or
    skin conductance? A projected 3D hologram? A permanent brain implant,
    heads-up display with GPS, TV, film, radio, communication and
    broadband? It sounds quite stressful! ;-)
    Chris.Bee, May 6, 2009
  8. See "Richter 10" by Arthur C. Clark. He calls it "chipped" if I remember
    correctly. Written in 1996 he was pretty good at forecasting the
    proliferation of cameras everywhere, not implanted yet but many people
    indeed can't live without their cell phones and blogs and spaces and
    texting and sexting and ... any more.

    Jürgen Exner, May 6, 2009
  9. Hughes

    Ofnuts Guest

    Monitor resolution ranges, due to market constraints, from "barely
    readable" (around 50dpi) to "we can make it more expensive but noone
    will see the difference" (around 200dpi). Sometimes there are
    explanations for miracles or even mere coincidences.
    Ofnuts, May 6, 2009
  10. In sci.astro.amateur message <
    Never quote an author whose name you are unable to spell correctly.

    "Richter 10" was co-authored, and probably largely written, by Mike
    Dr J R Stockton, May 7, 2009
  11. God how I WISH you were right!

    As someone who designs the FLIRs that produce images on those monitors,
    I am sorry to say that you are very wide of the mark.

    The drivers for selection of those monitors are, in order:
    Direct sunlight visibility
    Power dissipation

    I think I might have underplayed the importance of cost. ;-)

    Seriously, you only have a limited amount of space in a cockpit to fit a
    video display and it will be further from the pilot than you would like,
    so its practical resolution to the operator is always going to be well
    below SD TV standards, even if the display itself is much higher. Then
    there is aircraft vibration to consider. By the time its all added up,
    most of the time they can't tell the difference between Q-VGA and 720p
    HD! There are a couple of exceptions, where the image is not presented
    to just the pilot, but that is generally the case.
    Kennedy McEwen, May 8, 2009
  12. Hughes

    Chris.Bee Guest

    "Never" was a bit strong, JR, and your tone quite unwarranted despite
    your hero-worship of said author.

    Notwithstanding the typo, Jürgen's information was both useful and
    included the source.

    Will a simple flogging do?

    Or shall we chop of his hands before relieving him of his head?

    Perhaps you were hoping for the head as your prize to show off at
    Stockton Towers?

    Dare I suggest a search for <tact & tone> ?
    Chris.Bee, May 8, 2009
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