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<base href="http://fiji.sc/bugzilla/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Possible error when down-converting from 32- or 16-bit-depth images (to 16- or 8-bit)."
href="http://fiji.sc/bugzilla/show_bug.cgi?id=931">931</a>
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<th>Summary</th>
<td>Possible error when down-converting from 32- or 16-bit-depth images (to 16- or 8-bit).
</td>
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<th>Product</th>
<td>Fiji
</td>
</tr>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P5
</td>
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<th>Component</th>
<td>ImageJ1
</td>
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<th>Assignee</th>
<td>imagej-bugs@imagej.net
</td>
</tr>
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<th>Reporter</th>
<td>leonardo.guizzetti@gmail.com
</td>
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<pre>I seem to have a problem down-converting 32-bit to 16- or 8-bit images, or from
16-bit to 8 bit. It appears that even if the image histogram fits neatly inside
an 8-bit image, down-converting causes a re-scaling of all pixel values. My
FIJI and ImageJ1 are up-to-date.
Steps taken to produce the problem:
1) SCIFIO is off.
2) Open Blobs sample (ctrl+shift+b)
3) Measure original image statistics. Pixel values range from 8-248 (originally
8-bit colour image).
4) Convert image to 32-bit, and measure image stats. Pixel values remain the
same.
5) Convert back to 8-bit, and measure image stats. Now, pixel values range from
0-255, and histogram has been stretched to fit entire 8-bit range.
This behaviour seems abnormal to me, as I wouldn't expect the scaling to occur,
and could be destructive for image manipulation.</pre>
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