hardware resolution and optical resolution?

Discussion in 'Photography' started by JethroUK©, May 23, 2008.

  1. JethroUK©

    JethroUK© Guest

    Whats the difference between hardware resolution and optical resolution?
    Which should i look for to make like for like comparison?


    E.g. Epson Perfection 1670:

    Photoelectric Device
    Epson MatrixCCDT line sensor
    Maximum Scan Area
    8.5" x 11.7" (216mm x 297mm)
    Optical Resolution
    1600 dpi
    Hardware Resolution
    1600 x 3200 dpi maximum with Micro Step DriveT technology
    Maximum Resolution
    13,600 x 18,720 dpi with software interpolation
    Color Depth
    48-bit internal/48-bit external
    Grayscale Depth.....................
     
    JethroUK©, May 23, 2008
    #1
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  2. JethroUK©

    ray Guest

    I could be wrong, since this is not really my area of expertise, but my
    interpretation would be:

    a scanner sensor is typically a string rather than an area - it's physical
    resolution is 1600 dpi. This sensor string is moved to cover the area -
    the step driver is capable of postioning at 3200 dpi.
     
    ray, May 23, 2008
    #2
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  3.  
    Blinky the Shark, May 24, 2008
    #3
  4. The term they are using, "hardware resolution" with Micro Step means
    that while the basic optical resolution is 1600, they can achieve a
    sort of hybrid "super-resolution" by stepping the scan half that
    distance and applying some rather old software analysis to achieve
    3200. This is a pretty good technique and better than purely software
    "sharpening."

    Radars do this a lot.
     
    Don Stauffer in Minnesota, May 24, 2008
    #4
  5. JethroUK©

    Marvin Guest

    I see it as "specsmanship". The pixel counts, assuming no
    signal-spreading between pixels, defines the possible
    resolution across the image in an image if the optics are
    good enough not to limit resolution. The step interval
    defines the possible vertical resolution, with a similar
    proviso. Software interpolation, by the scan software or by
    image editing software, cannot actually increase resolution.
    It would require having more information about the content
    of the image;where could that come from?

    The true test is from a scan (or photo) of a resolution chart.
     
    Marvin, May 24, 2008
    #5
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