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76 wiersze
3.6 KiB
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<!-- received="Mon Sep 1 06:36:39 1997 MST" -->
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<!-- sent="Mon, 01 Sep 1997 13:45:46 +0100" -->
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<!-- name="Jonathan A. Buzzard" -->
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<!-- email="jab@hex.prestel.co.uk" -->
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<!-- subject="Re: umax-backend" -->
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<!-- id="m0x5VrW-000J8HC@hex.prestel.co.uk" -->
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<!-- inreplyto="umax-backend" -->
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<title>sane-devel: Re: umax-backend</title>
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<h1>Re: umax-backend</h1>
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<b>Jonathan A. Buzzard</b> (<a href="mailto:jab@hex.prestel.co.uk"><i>jab@hex.prestel.co.uk</i></a>)<br>
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<i>Mon, 01 Sep 1997 13:45:46 +0100</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#119">[ date ]</a><a href="index.html#119">[ thread ]</a><a href="subject.html#119">[ subject ]</a><a href="author.html#119">[ author ]</a>
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<li> <b>Next message:</b> <a href="0120.html">Oliver.Rauch@Wolfsburg.DE: "umax-backend"</a>
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<li> <b>Previous message:</b> <a href="0118.html">Rogier Wolff: "Re: Backtracking in color scanning"</a>
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<li> <b>Maybe in reply to:</b> <a href="0120.html">Oliver.Rauch@Wolfsburg.DE: "umax-backend"</a>
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<!-- nextthread="start" -->
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<li> <b>Next in thread:</b> <a href="0121.html">Rogier Wolff: "Re: umax-backend"</a>
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<li> <b>Reply:</b> <a href="0121.html">Rogier Wolff: "Re: umax-backend"</a>
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</ul>
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<a href="mailto:R.E.Wolff@BitWizard.nl">R.E.Wolff@BitWizard.nl</a> said:<br>
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<i>> Yes, the q/a program will show "only noise" still, the doctors won't </i><br>
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<i>> allow you to trhow away that information. Maybe if you average 4 </i><br>
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<i>> pixels together that you get a little information. This IS visible to </i><br>
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<i>> the naked eye..... </i><br>
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<p>
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Never said the radiologist would let you throw the info away, but noise<br>
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is noise and averaging bits together will (should)<br>
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<p>
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<i>> How do you measure the "just noise" in a 12bit scanner? I'd try to </i><br>
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<i>> generate a perfect analog greyscale and scan that.</i><br>
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<p>
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Not that I was involved in the q/a program, (it was an M.Sc. project done<br>
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at the same time as mime, and I had to use the same scanner for some<br>
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radiotherapy films). Roughly their was a test film which had a large number<br>
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of squares of different (but uniform) optical density. Roughly a scan was<br>
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taken of the film, a template was placed over the image and some statistics<br>
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where done on the pixels of the different areas. As far as I understood<br>
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the analysis showed that on a uniform area the distribution of the values<br>
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in the lower two bits was more or less uniform. The conclusions drawn from<br>
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that it must be noise.<br>
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<p>
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<p>
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JAB.<br>
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<p>
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<p>
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<pre>
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--
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Jonathan A. Buzzard,
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34 Kepwell Road, Prudhoe, Email: <a href="mailto:jab@hex.prestel.co.uk">jab@hex.prestel.co.uk</a>
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Northumberland. NE42 6PD Tel: +44(0)1661-832195
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United Kingdom
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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.azstarnet.com/~axplinux/sane/">http://www.azstarnet.com/~axplinux/sane/</a>
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To unsubscribe: mail -s unsubscribe <a href="mailto:sane-devel-request@listserv.azstarnet.com">sane-devel-request@listserv.azstarnet.com</a>
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</pre>
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<!-- body="end" -->
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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="0120.html">Oliver.Rauch@Wolfsburg.DE: "umax-backend"</a>
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<li> <b>Previous message:</b> <a href="0118.html">Rogier Wolff: "Re: Backtracking in color scanning"</a>
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<li> <b>Maybe in reply to:</b> <a href="0120.html">Oliver.Rauch@Wolfsburg.DE: "umax-backend"</a>
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<!-- nextthread="start" -->
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<li> <b>Next in thread:</b> <a href="0121.html">Rogier Wolff: "Re: umax-backend"</a>
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<li> <b>Reply:</b> <a href="0121.html">Rogier Wolff: "Re: umax-backend"</a>
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<!-- reply="end" -->
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</ul>
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