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<p class=MsoNormal><span lang=EN-US>Hi,<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>I tried to load a DICOM MONOCHROME1 image
(MG) and resulting output values are outside the range specified in the DICOM
fields. The resulting image is shown in black with the W/L settings taken from
DICOM.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Debugging a bit and getting deep into ITK, it
seems like the problem lies in the GDCM library in gdcm::PixelReadConvert::ConvertFixGreyLevels()
and the interpretation of (0028,0120) Pixel Padding Value and (0028,0107)
Largest Image Pixel Value. For this image, the Largest Image Pixel Value is
32767 and the Pixel Padding Value 32767 (recommended to be 2^16-1 = 65535) but
not mandatory.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>In
gdcm::PixelReadConvert::ConvertFixGreyLevels() always pixels are converted in
the form:<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>value = 65535 - value<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>which results in pixels above the 5571 -
32767 range for this image.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>In my opinion, in this case it should be <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal>value = 32767 - value<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span lang=EN-US>which gives the correct values.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>I am not totally sure, but the image seems
to be following the standard. Could please someone confirm this?<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>We have several of these images and none is
loading correctly<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>I added a new bug entry in Mantis for this<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><a
href="http://public.kitware.com/Bug/view.php?id=8538">http://public.kitware.com/Bug/view.php?id=8538</a><o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Thanks in advance <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Iván<o:p></o:p></span></p>
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