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<title>sane-devel: Re: Scanning and interpolation</title>
<h1>Re: Scanning and interpolation</h1>
<a href="mailto:becka@rz.uni-duesseldorf.de"><i>becka@rz.uni-duesseldorf.de</i></a><br>
<i>Fri, 23 Apr 1999 20:09:03 +0200 (MEST)</i>
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Hi !<br>
<p>
<i>&gt; The best result is obtained by scanning in 1200 dpi and reducing the </i><br>
<i>&gt; file with jpg compression, even though I had expected scanning in 300</i><br>
<i>&gt; dpi to as good as 1200 dpi.</i><br>
<p>
<i>&gt; SANE does no interpolation and will only deliver the optical resolution </i><br>
<i>&gt; of the scanner. Is the apparent enhancement of the picture only an</i><br>
<i>&gt; illusion?</i><br>
<p>
Yes. Interpolation does not add any "inormation". It just places a grey pixel<br>
between a black and a white one.<br>
<p>
<i>&gt; It might be a good idea to introduce interpolation into SANE ? </i><br>
<p>
No. It just adds useless data that carries no information to the output.<br>
<p>
<i>&gt; Is the algorithms behind this free ? </i><br>
<p>
I hope so. If someone patented this : <br>
<p>
interpolated_pixel(between_pixel_1_and_pixel_2)=<br>
( pixel_1*distance_to_1+<br>
pixel_2*distance_to_2) /<br>
( distance_to_1+distance_to_2 )<br>
<p>
he is definitely insane.<br>
<p>
<i>&gt; How is the interpolation done ? Close to the hardware or on the picture</i><br>
<i>&gt; after scanning ? E.g. could it be done in GIMP ? -</i><br>
<p>
Yes - choose "resample".<br>
<p>
CU, ANdy<br>
<p>
<pre>
--
= Andreas Beck | Email : &lt;<a href="mailto:andreas.beck@ggi-project.org">andreas.beck@ggi-project.org</a>&gt; =
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