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Re: doc-view: Document quality and find-file


From: Amy Templeton
Subject: Re: doc-view: Document quality and find-file
Date: Mon, 17 Sep 2007 18:15:44 -0400
User-agent: Gnus/5.11 (Gnus v5.11) Emacs/23.0.50 (gnu/linux)

Peter Dyballa <Peter_Dyballa@Web.DE> wrote:
> Am 17.09.2007 um 20:59 schrieb Amy Templeton:

> >  article will be scanned

> So your PDFs are not generated by some text system, but scanned pages from
> books or magazines! This of course explains that the characters will look
> ragged: printing is not perfect and scanning is even farther away from
> perfection. I presume the corners of the characters might look better when
> you use a resolution that is one half, one quarter, or one eighth etc. of
> the original scan's resolution. This way small distortions will get
> averaged. And this effect allows to reduce the amount of anti-aliasing
> Ghostscript uses to create the PNG picture. 

Ah, of course. I guess that should've occurred to me. However, reduced sizes
just seem to make it worse, oddly, whereas larger ones make it easier to
read. I don't presume to have an explanation.

> And depending on the actual bit depth of the scan you might adjust the PNG
> device for which gs converts the PDF file. It's useless to expand an 8-bit
> image to 24 bits.

Fair enough. I'll look into it.

> You know that you can't search a text in such a scan?

Oh, you're right. I can do it in a lot of the articles I read, though,
because they're from academic journals' sites, which I guess do things
right.

> OTOH, an OCR software could improve the scans ...

OCR? I'm not familiar with that term. Also, I doubt I'd be able to convince
my school to switch to anything decent...I mean, the campus computer
repair/maintenance/IT people *brag* on their website that all the software
they use and that they provide for students is proprietary. This is extra
weird because in most other realms, my school is fairly activistic as these
things go and so actually does a surprising number of things *right* (for
example, working to provide handicapped access even to older buildings). But
all that's another story altogether. Thanks for the tip, though.

Amy

-- 
If you are honest because honesty is the best policy, your honesty is
corrupt.




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