sane-project-website/old-archive/1999-03/0227.html

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<title>sane-devel: Re: Scanner survey results</title>
<h1>Re: Scanner survey results</h1>
<b>Henning Meier-Geinitz</b> (<a href="mailto:hmg-ml@gmx.de"><i>hmg-ml@gmx.de</i></a>)<br>
<i>Wed, 24 Mar 1999 23:17:11 +0100</i>
<p>
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[mustek 600 II N ver. 1.01]<br>
<i>&gt; Yes, unfortunately I have one with firmware 1.01, and I have </i><br>
<i>&gt; problems with color scanning. Currently I have Sane-pre1.01-2 on </i><br>
<i>&gt; my system. What options should one set in mustek.conf to get the </i><br>
<i>&gt; best possible results with this scanner?</i><br>
<p>
Possibly a patch I posted some months ago can help a bit. It's against<br>
an older version of sane but I think it will work with your version,<br>
too. Perhaps you have to tweak it a bit.<br>
<p>
Something like patch -p1 &lt;patch.file in the sane directory should do<br>
it.<br>
<p>
Here is the old article describing the problem:<br>
<p>
------------------------ snip ---------------------------------------<br>
From: Henning Meier-Geinitz &lt;<a href="mailto:henningmg@gmx.de">henningmg@gmx.de</a>&gt;<br>
To: <a href="mailto:sane-devel@mostang.com">sane-devel@mostang.com</a><br>
Subject: line-distance correction and mustek 600 II N<br>
Sender: <a href="mailto:owner-sane-devel@mostang.com">owner-sane-devel@mostang.com</a><br>
<p>
I looked into the line-distance correction code for the mustek 600 II<br>
N in mustek.c. Some details are explained in an earlier article. With<br>
the patch color works somewhat, but there are missing lines at the<br>
end. The problem is: The scanner sends data one line after the other<br>
in the following manner (Example):<br>
<p>
R-R-R-R-B-B-R-B-G-R-B-G ... R-G-B-R-G-B<br>
<p>
If n is the distance between two CCD lines, sane loses 3*n data lines<br>
at the end of the scan. The line-distance code in sane asumes the<br>
following:<br>
<p>
R-R-R-R-B-B-R-B-G-R-B-G ... R-G-B-G-B-G-B-G-G-G<br>
<p>
If I understood correctly, mustek.c would have to scan n more lines<br>
then specified to get the full sized image. I don't know most<br>
internals of mustek.c so I can't do this.<br>
<p>
By the way: My 600 II N doesn't need the line-distance-fix, the<br>
line-distance values which it sends are correct. I don't know, if this<br>
applies for all 600 II N.<br>
<p>
The following patch corrects the color scanning problem with the 600<br>
II N as far as I can do it. It will (hopefully) fix the problem with<br>
not ignoring empty lines in mustek.conf. And I put a usleep in<br>
sanei_ab306.c. This will allow to run sane without turning on<br>
debugging (which was the only way to get sane with the 600 II N to<br>
work for me). I don't know, why it works, but it does.<br>
       <br>
<p>
---------------------------- snip ----------------------------------<br>
<p>
... and here is the patch (only the color correction, the rest should<br>
have been included in sane):<br>
<p>
---------------------------- snip ----------------------------------<br>
diff -ru sane-0.72.orig/backend/mustek.c sane-0.72/backend/mustek.c<br>
--- sane-0.72.orig/backend/mustek.c	Tue Mar  3 04:02:43 1998<br>
+++ sane-0.72/backend/mustek.c	Mon Apr 13 21:25:53 1998<br>
@@ -1394,7 +1394,7 @@<br>
 	}<br>
     }<br>
 <br>
-  num_saved_lines = s-&gt;ld.index[0] - s-&gt;ld.index[2];<br>
+  num_saved_lines = s-&gt;ld.index[0] - s-&gt;ld.index[1];<br>
   if (num_saved_lines &gt; 0)<br>
     /* restore the previously saved lines: */<br>
     memcpy (out, s-&gt;ld.buf[0], num_saved_lines * bpl);<br>
@@ -1404,10 +1404,10 @@<br>
       if (++s-&gt;ld.lmod3 &gt;= 3)<br>
 	s-&gt;ld.lmod3 = 0;<br>
 <br>
-      c = color_seq[s-&gt;ld.lmod3];<br>
+      c = s-&gt;ld.lmod3;<br>
       if (s-&gt;ld.index[c] &lt; 0)<br>
 	++s-&gt;ld.index[c];<br>
-      else if (s-&gt;ld.index[c] &lt; s-&gt;params.lines)<br>
+      else /*if (s-&gt;ld.index[c] &lt; s-&gt;params.lines)*/<br>
 	{<br>
 	  s-&gt;ld.c[c].Qk += s-&gt;ld.peak_res;<br>
 	  if (s-&gt;ld.c[c].Qk &gt; s-&gt;ld.max_value)<br>
@@ -1421,17 +1421,17 @@<br>
 		  DBG (1, "fix_line_distance_pp: lmod3=%d, index=(%d,%d,%d)\n",<br>
 		       s-&gt;ld.lmod3,<br>
 		       s-&gt;ld.index[0], s-&gt;ld.index[1], s-&gt;ld.index[2]);<br>
-		  num_lines = s-&gt;ld.index[2] - s-&gt;ld.ld_line;<br>
+		  num_lines = s-&gt;ld.index[1] - s-&gt;ld.ld_line;<br>
 <br>
 		  /* copy away the lines with at least one missing<br>
 		     color component, so that we can interleave them<br>
 		     with new scan data on the next call */<br>
-		  num_saved_lines = s-&gt;ld.index[0] - s-&gt;ld.index[2];<br>
+		  num_saved_lines = s-&gt;ld.index[0] - s-&gt;ld.index[1];<br>
 		  memcpy (s-&gt;ld.buf[0], out + num_lines * bpl,<br>
 			  num_saved_lines * bpl);<br>
 <br>
 		  /* notice the number of lines we processed */<br>
-		  s-&gt;ld.ld_line = s-&gt;ld.index[2];<br>
+		  s-&gt;ld.ld_line = s-&gt;ld.index[1];<br>
 		  /* return number of complete (r+g+b) lines */<br>
 		  return num_lines;<br>
 		}<br>
---------------------------- snip ----------------------------------<br>
<p>
<p>
hth, Henning<br>
<p>
<pre>
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<li> <b>Next message:</b> <a href="0228.html">Hugo van der Kooij: "Re: driver dev advice"</a>
<li> <b>Previous message:</b> <a href="0226.html">Henning Meier-Geinitz: "Re: xsane-0.18 available"</a>
<li> <b>In reply to:</b> <a href="0223.html">Johan Bengtsson: "Re: Scanner survey results"</a>
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