RE: To David Soderman: A Little Test

["gary" <gsellani@xxxxxxxxxxxxx>]

You need to consider that the LED illumination could have variance. If you
have ever tried to design a dimmer for a CCFT, you would learn that they do
not dim very well, while a LED has an exponential element to its light
output versus current. You can send analog signals over led/phototransistor
setups, something commonly done in the PCMCIA modem cards.

I see no reason for the 3 line CCD to have more variance. The filter over
each line is stable, the CCFT light is stable and there is no effect on
position accuracy since the film is uniform in both dimensions.


> -----Original Message-----
> From: owner-scan@leben.com [mailto:owner-scan@leben.com]On Behalf Of
> Arthur Entlich
> Sent: Monday, April 08, 2002 4:24 AM
> To: scan@leben.com
> Subject: Re: To David Soderman: A Little Test
>
>
> I'm trying to understand the nature of this test and its value.
>
> Nikon scanners, and particularly the 8000ED in super fine mode, uses the
> same CCD sensor line for all three color scans.  The only thing that
> changes is the color of the LED lighting source.
>
> The Minolta, on the other hand, uses three distinct CCD lines, each one
> through a different colored filter, one red, one green and one blue.
>
> One would expect that the later system, as used on all scanners but the
> Nikon, would show more variation since each color uses a unique set of
> elements, and a unique filter.
>
> So, I guess I'm wondering what the results of such a test mean.
>
> What might be more interesting is testing the Nikon in normal mode
> rather than super fine to see how the three lines of elements respond
> when two are not calibrated, and repeat the test several times.
>
> Art
>
> East75th wrote:
>
> > David:
> >
> > You might try this to compare your Minolta to the LS-8000:
> >
> > http://www.marginalsoftware.com/Temp/scan_of_a_wratten_96_filter.htm
> >
> > I make no claims of superiority or inferiority.  This is simply a rough
> > test of how consistently your scanner reads an essentially monochrome
> > image *independent* of grain.
> > I'd really be interested in your results (the standard deviations of
> > each of the 3 channels).
> >
> > I hope you've been eating your chicken soup.
> >
> > Dane Kosaka
>
>
> -
> Turn off HTML mail features. Keep quoted material short. Use accurate
> subject lines. http://www.leben.com/lists for list instructions.
>
>

-
Turn off HTML mail features. Keep quoted material short. Use accurate
subject lines. http://www.leben.com/lists for list instructions.