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<!-- received="Thu Mar 25 18:15:49 1999 PST" -->
<!-- sent="Thu, 25 Mar 1999 18:15:16 -0800" -->
<!-- name="Dean Martin Townsley" -->
<!-- email="townsley@physics.ucsb.edu" -->
<!-- subject="Re: Calibration problem on UMAX Astra 1220S" -->
<!-- id="199903260214.SAA05950@spacecase.physics.ucsb.edu" -->
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<title>sane-devel: Re: Calibration problem on UMAX Astra 1220S</title>
<h1>Re: Calibration problem on UMAX Astra 1220S</h1>
<b>Dean Martin Townsley</b> (<a href="mailto:townsley@physics.ucsb.edu"><i>townsley@physics.ucsb.edu</i></a>)<br>
<i>Thu, 25 Mar 1999 18:15:16 -0800</i>
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Hey Oliver, thanks for the quick response, sorry I'm slow, had exams.<br>
Comments below:<br>
<p>
<i>&gt; </i><br>
<i>&gt; From: Oliver Rauch &lt;<a href="mailto:oliver.rauch@Wolfsburg.DE">oliver.rauch@Wolfsburg.DE</a>&gt;</i><br>
<i>&gt; Dean Martin Townsley wrote:</i><br>
<i>&gt; </i><br>
<i>&gt; &gt; Hi all,</i><br>
<i>&gt; &gt; My problem with the calibration is simple: I can't get it to perform the</i><br>
<i>&gt; &gt; calibration. I'm using sane 1.00 with the build-1 patch for the umax drivers</i><br>
<i>&gt; &gt; and xsane 0.18 for the frontend (tried xscanimage too).</i><br>
<i>&gt; &gt; I stuck a debug message in the code to supplement the messages already</i><br>
<i>&gt; &gt; there and found that dev-&gt;do_calibration was zero when the scan process went</i><br>
<i>&gt; &gt; through the do_calibration() function even when the box for "Quality</i><br>
<i>&gt; &gt; Calibration" was checked in the interface. The code checks and to me seems</i><br>
<i>&gt; &gt; to only perform the calibration if this is nonzero. I don't know if this is</i><br>
<i>&gt; &gt; a problem in the driver itself or somewhere else but both xsane and</i><br>
<i>&gt; &gt; xscanimage exhibit the same problem. That's as far as I got, I have final</i><br>
<i>&gt; &gt; exams for the next two days (take homes) so I won't be able to fiddle again</i><br>
<i>&gt; &gt; until after that probably, but I figured I'd say something so someone with</i><br>
<i>&gt; &gt; better knowledge of the code can maybe investigate.</i><br>
<i>&gt; &gt;</i><br>
<i>&gt; &gt; oh, btw, /proc/scsi/scsi says</i><br>
<i>&gt; &gt; Host: scsi0 Channel: 00 Id: 05 Lun: 00</i><br>
<i>&gt; &gt; Vendor: UMAX Model: Astra 1220S Rev: V1.1</i><br>
<i>&gt; &gt; Type: Scanner ANSI SCSI revision: 02</i><br>
<i>&gt; &gt;</i><br>
<i>&gt; &gt; Which I presume means it's firmware 1.1, (out of a possible 1.5, ugh).</i><br>
<i>&gt; &gt;</i><br>
<i>&gt; </i><br>
<i>&gt; Hi Dean,</i><br>
<i>&gt; </i><br>
<i>&gt; like described in the sane-umax-docs the quality calibration does not work with</i><br>
<i>&gt; all scanners!</i><br>
<p>
I thought I remembered seeing this but still can't find it on the web page at<br>
least. So which ones does it work with?<br>
<p>
<i>&gt; What happens or does not happen if you enable quality calibration?</i><br>
<p>
Okay I'll let you know the story. I'm trying to scan a card that's basically<br>
an embossed white graphic on a slightly off-white background. Well, the<br>
scanner sees that the thing is almost totally white, and saturates the scan<br>
really bad. The histogram in xsane does not fall off at the high<br>
Luminosities, it just saturates. From looking at other stuff on the net,<br>
this appears abnormal, even for stuff on white backgrounds. I am under the<br>
ipression that this is what the "Quality Calibration" is for (though I could<br>
be wrong) is to set the white point so that it is not out of the scanner's<br>
sensing range, as it apparently is on mine since white and off-white come up<br>
as the same color -- ffffff white. I would assume it's just an impossible<br>
scan but someone else did it on another scanner and it came out fine, I'm<br>
just trying to match that (and not even coming close).<br>
Now for what happens when when I try to use the calibration. Nothing.<br>
There is no noticable difference in the scans or the activity performed by<br>
the scanner. I assume that even if the firmware is doing the calibration<br>
that it still has to DO something i.e. the lamp has to move prior to the<br>
actual scan. (Again I could be wrong let me know if I am) In my case I find<br>
no difference between having the button checked or not in the frontend.<br>
<p>
<i>&gt; Background:</i><br>
<i>&gt; There are some problems with calibration by driver. UMAX uses a different</i><br>
<i>&gt; kind of calibration for each scanner model and firmware. I only know the one of</i><br>
<i>&gt; the Umax Supervista S12 with firmware 2.0.</i><br>
<i>&gt; </i><br>
<i>&gt; If you set the quality calibration button, the driver requests a quality</i><br>
<i>&gt; calibration</i><br>
<i>&gt; from the scanner. If the scanner is not able to do the quality calibration on</i><br>
<i>&gt; its own,</i><br>
<i>&gt; it requests the driver to do this. In that case do_calibration is set in the</i><br>
<i>&gt; driver.</i><br>
<i>&gt; Then the scanner sends the calibration data, the driver does the calibration and</i><br>
<i>&gt; </i><br>
<i>&gt; sends back the calibration data.</i><br>
<i>&gt; </i><br>
<i>&gt; If the scanner does not request that the driver has to do the calibration, there</i><br>
<i>&gt; is</i><br>
<i>&gt; nothing what the driver can do.</i><br>
<p>
Hopefully I'm not totally off base here. I think my scanner is capable of<br>
doing calibration, since the starting of the driver says<br>
[umax] f/w support function:<br>
[umax] ---------------------<br>
[umax] quality calibration<br>
but it likely performs it in the firmware, since the<br>
"change" to firmware 1.5 for this scanner was to add software calibration.<br>
<p>
I think I could do better if I had an idea what I was looking for. What is<br>
the Quality Calibration supposed to work like? Should it happen at the<br>
beginning of each scan when the button is checked? Should the scan process<br>
be different? A two pass scan maybe? If it's not working is this because<br>
the driver is just not telling the scanner to do it properly? Is this<br>
documented anywhere or is this a trial and error type thing?<br>
<i>&gt; </i><br>
<i>&gt; Bye</i><br>
<i>&gt; Oliver</i><br>
<i>&gt; </i><br>
Thanks for the help, and thanks for your work on the driver, it scans<br>
photographs great!<br>
Regards,<br>
-Dean Townsley<br>
<p>
<pre>
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