Archived posting to the Leica Users Group, 2001/07/25

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Subject: RE: [Leica] Scanning
From: "Austin Franklin" <darkroom@ix.netcom.com>
Date: Wed, 25 Jul 2001 09:02:31 -0400

> > Which means you need a scanner of 5400 SPI
> > to reliably detect your 53 lp/mm...
>
> Nope.  53 lp/mm times two = 106 lp/mm, or 2692 dpi.

As I pointed out, that's completely wrong and shows your lack of
understanding of the subject.

> The whole field of digital image capture and workflow is based on
> information
> theory,

That's a load of crap.  Digital image capture is NOT based on "information
theory", there are certainly SOME aspects of it that are relevant.  It
sounds to me like you are trying to believe your knowledge is more important
and encompassing than it really is.

> The fact that a
> scanner you design might need more than 2x sampling to achieve
> some resolution
> does not mean that this is any kind of absolute rule.

Wrong.  I have shown, why that IS a rule.  It's such a basic rule of signal
processing, it is obviously you don't have any real background in this
field.

If you really believe yourself, then show me that you can design a scanner
that can reliably scan a line of .009mm with a sensor that is .009mm without
doing some technique to (effectively) increase the sample rate.  Moving
things does increase the sample rate, BTW.

My guess is, since you believe something that is entirely incorrect, you
would come up with something that you will just continue to claim works,
even when shown that it doesn't, then you'd change the criteria.  Either you
are too arrogant to admit you are mistaken, don't understand enough to
understand you are wrong, or are playing games...or some combination of the
three.

> > No better teacher than experience.
>
> Usually a blend of theory and experience is best, IMO.

And you, obviously, have no experience in this field, and also lack in the
related theory.

> > I have clearly shown, and I'd have to believe,
> > given your response here, that you agree, that
> > you need to sample at >2x to "reliably" RESOLVE
> > a line.
>
> Yes.  But at 2700 dpi, you are doing precisely that for a
> resolution of 53 lp/mm
> (2700 dpi is actually 53.14 lp/mm).

Er, wrong again.  If you don't understand why, then as I said, you just
don't comprehend the basics of digital signal processing, period.

You're a real cuss.  I'm done with either your ignorance, arrogance or
games, which ever it is, I really don't care.  What you believe IS wrong.
It does not make you right by constantly repeating a statement that is just
plain wrong.

Replies: Reply from "Mxsmanic" <mxsmanic@hotmail.com> (Re: [Leica] Scanning)