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<!-- name="Ewald R. de Wit" -->
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<title>sane-devel: Re: SANE V2 - again...</title>
<h1>Re: SANE V2 - again...</h1>
<b>Ewald R. de Wit</b> (<a href="mailto:ewald@pobox.com"><i>ewald@pobox.com</i></a>)<br>
<i>Tue, 31 Aug 1999 10:02:24 +0200</i>
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<li> <b>Next message:</b> <a href="0362.html">Dan Kegel: "Re: Newbie Q: Accessing Scanport SQ4800 via SANE"</a>
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abel deuring (<a href="mailto:a.deuring@satzbau-gmbh.de">a.deuring@satzbau-gmbh.de</a>) wrote:<br>
<p>
<i>&gt; I would like to extend the topic of colour correction: Having a quite</i><br>
<i>&gt; simple option for a linear transformation is of course fine in many</i><br>
<i>&gt; situations, but it is not enough for high quality scans. [OK, the</i><br>
<i>&gt; following mixes the topics of colour correction and calibration...] Look</i><br>
<i>&gt; for example into some documents of the ICC</i><br>
<i>&gt; (<a href="http://www.color.org/profiles.html">http://www.color.org/profiles.html</a> or</i><br>
<i>&gt; <a href="http://www.color.org/iccprofiles.html">http://www.color.org/iccprofiles.html</a>): The ICC profiles allow for</i><br>
<i>&gt; non-linear transformations in order to achieve better quality. A quite</i><br>
<i>&gt; complicated but perhaps useful approach to use ICC profiles within Sane</i><br>
<i>&gt; qould be a transformation </i><br>
<i>&gt; </i><br>
<i>&gt; raw</i><br>
<i>&gt; scan -----------------&gt; CIELab ------------------------&gt; output</i><br>
<i>&gt; data mapped using data mapped using an data</i><br>
<i>&gt; an ICC profile ICC profile for </i><br>
<i>&gt; for the scanner CRT tubes </i><br>
<i>&gt; (or whatever)</i><br>
<p>
Nearly all scanners use CCD or CMOS sensors which are inherently linear<br>
devices so there would be no practical need for doing non-linear color<br>
transforms. A 3x3 matrix followed by a tonemap would be good enough.<br>
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--
-- Ewald
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<li> <b>Next message:</b> <a href="0362.html">Dan Kegel: "Re: Newbie Q: Accessing Scanport SQ4800 via SANE"</a>
<li> <b>Previous message:</b> <a href="0360.html">Tom Martone: "Re: SANE V2 - again..."</a>
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