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[filmscanners] RE: Density vs Dynamic range>AUSTIN (2a)



This is really getting pointless. You're bullheadedly insisting upon
arbitrary philosophical definitions for words, when in reality the original
issue (I thought) was whether scanners need frequency response down to DC.

> > If DC doesn't represent information,
> > then removing the DC component should have
> > no effect on the functioning of the scanner.
>
> Correct.  But scanners don't have DC components.

Of course they do. The DC component is the average voltage present during
the scan. Or in optical terms, if you do a 2D Fourier transform of the
image, it's the value of the (0,0) bin. If you throw that value away, your
image will not be reproduced correctly.

> > To make a scanner, you need a frequency
> > response down to DC.
>
> But to convey information, you need a non-zero frequency, and
> thus you need
> something _other_ than DC.

I never said that a scanner _only_ used DC. It uses frequency components
from zero up to half the sampling rate.

--

Ciao,               Paul D. DeRocco
Paul                mailto:pderocco@ix.netcom.com

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