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69 wiersze
3.2 KiB
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<!-- received="Fri Apr 23 00:59:10 1999 PDT" -->
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<!-- sent="Fri, 23 Apr 1999 09:59:11 +0200 (MET DST)" -->
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<!-- name="Ole W. Saastad" -->
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<!-- email="o.w.saastad@kjemi.uio.no" -->
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<!-- subject="Scanning and interpolation" -->
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<title>sane-devel: Scanning and interpolation</title>
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<h1>Scanning and interpolation</h1>
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<b>Ole W. Saastad</b> (<a href="mailto:o.w.saastad@kjemi.uio.no"><i>o.w.saastad@kjemi.uio.no</i></a>)<br>
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<i>Fri, 23 Apr 1999 09:59:11 +0200 (MET DST)</i>
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<p>
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<ul>
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<li> <b>Messages sorted by:</b> <a href="date.html#321">[ date ]</a><a href="index.html#321">[ thread ]</a><a href="subject.html#321">[ subject ]</a><a href="author.html#321">[ author ]</a>
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<li> <b>Next message:</b> <a href="0322.html">becka@rz.uni-duesseldorf.de: "Re: Scanner internals and SANE backends"</a>
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<li> <b>Previous message:</b> <a href="0320.html">Alex Belits: "Re: Star Office and scanner"</a>
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</ul>
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I have played some time with scanning software (AGFA and HP) and <br>
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especially tested the best way of scanning, 100, 200, 300 dpi, and <br>
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1200 dpi (interpolated). The file size differ a lot but they are reduced <br>
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afterwards to equal with jpg compression. Apparently it looks like the <br>
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interpolation routines (HP) do a good job. It looks like the picture <br>
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scanned with 1200 dpi have higher resolution than the one scanned with <br>
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only 300 dpi, which is the optical resolution of the scanner.<br>
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The best result is obtained by scanning in 1200 dpi and reducing the <br>
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file with jpg compression, even though I had expected scanning in 300<br>
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dpi to as good as 1200 dpi.<br>
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<p>
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SANE does no interpolation and will only deliver the optical resolution <br>
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of the scanner. Is the apparent enhancement of the picture only an<br>
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illusion?<br>
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It seems that the resolution is higher also when blowing the picture up<br>
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to see each individual pixel. Even if the illusion is only apparent to the<br>
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eye it could in many cases make the pictures look better.<br>
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<p>
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It might be a good idea to introduce interpolation into SANE ? Is the<br>
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algorithms behind this free ? Or are these routines known for all ?<br>
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How is the interpolation done ? Close to the hardware or on the picture<br>
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after scanning ? E.g. could it be done in GIMP ? - Or must it be a driver<br>
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routine ?<br>
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<p>
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None of the companies that make scanners have introduced Linux software<br>
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yet. Agfa has stated that it newer will. The other say they will wait<br>
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and see. With 10 million Linux users growing 25% a annum Linux support<br>
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will emerge.<br>
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<p>
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<p>
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Ole W Saastad <br>
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<p>
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<p>
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<pre>
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--
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Source code, list archive, and docs: <a href="http://www.mostang.com/sane/">http://www.mostang.com/sane/</a>
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</pre>
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<p>
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<ul>
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<!-- next="start" -->
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<li> <b>Next message:</b> <a href="0322.html">becka@rz.uni-duesseldorf.de: "Re: Scanner internals and SANE backends"</a>
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<li> <b>Previous message:</b> <a href="0320.html">Alex Belits: "Re: Star Office and scanner"</a>
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<!-- nextthread="start" -->
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</ul>
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