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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.....................

On Fri, 23 May 2008 22:48:12 +0100, JethroUK© wrote:

> 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.....................

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.

JethroUK© wrote:

> Whats the difference between hardware resolution and optical resolution?

<chuckle> I just asked this in my reply to your reply about the V100's
resolution, where I pasted numbers for that one.

> 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.....................
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On May 23, 4:48 pm, JethroUK© <re...@the.board> wrote:
> 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.....................

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.

JethroUK© wrote:
> 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.....................

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.