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<DIV><SPAN class=289525212-17102002><FONT size=2>I spent a few hours last night
tracking down a problem with my use of ImageViewer2. Since ImageViewer2 uses the
3D rendering pipeline, I was tricked into thinking it would be trivial to use
the ImageViewer2 to show an intensity image and I could simple add another
actor to the ImageViewer2's renderer to display a segmentation overlaid on the
intensity image. The segmentation technique uses level sets so I used
Marching Squares to extract the zero set as PolyData to overlay on the
image. </FONT></SPAN></DIV>
<DIV><SPAN class=289525212-17102002><FONT size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=289525212-17102002><FONT size=2>Now, the output of Marching
Squares did not line up properly with the original image. I believe the
issue is that Marching Squares took into account the data spacing while the
ImageViewer2/ImageActor combination does not take into account the data
spacing.</FONT></SPAN></DIV>
<DIV><SPAN class=289525212-17102002><FONT size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=289525212-17102002><FONT size=2>I know that we have struggled
with this in the past, but should the ImageActor use the pixel spacing to
determine the "bounds" (and hence the projection) of the image? 'Course
sometimes you do want to view an image as if the pixels were isotropic or unit
size. Perhaps it could be a mode to turn on/off pixel
spacing.</FONT></SPAN></DIV>
<DIV><SPAN class=289525212-17102002><FONT size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=289525212-17102002><FONT size=2>I has a number of options to
get around this issue, scaling my polydata actor, using ImageChangeInformation,
etc. so it wasn't too hard to get around. However, it did take me awhile
to determine the use and lack of use of the data spacing was what was causing my
grief (I had assumed the problem was with my multi-resolution scale space, not
with the rendering...)</FONT></SPAN></DIV>
<DIV class=Section1>
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<P style="MARGIN: 0in 0in 0pt"><B><SPAN
style="COLOR: navy; FONT-FAMILY: 'Comic Sans MS'">Jim Miller</SPAN></B>
<BR><B><I><SPAN
style="FONT-SIZE: 10pt; COLOR: red; FONT-FAMILY: Arial">_____________________________________</SPAN></I></B><BR><EM><SPAN
style="FONT-SIZE: 7.5pt; COLOR: black; FONT-FAMILY: Arial">Visualization &
Computer Vision</SPAN></EM><I><SPAN
style="FONT-SIZE: 7.5pt; COLOR: black; FONT-FAMILY: Arial"><BR><EM>GE
Research</EM><BR><EM>Bldg. KW, Room C218B</EM><BR><EM>P.O. Box 8, Schenectady NY
12301</EM><BR><BR></SPAN></I><EM><U><SPAN
style="FONT-SIZE: 7.5pt; COLOR: blue"><A
href="mailto:millerjv@research.ge.com">millerjv@research.ge.com</A></SPAN></U></EM></P>
<P style="MARGIN: 0in 0in 0pt"><EM><U><SPAN
style="FONT-SIZE: 7.5pt; COLOR: blue">james.miller@research.ge.com</SPAN></U></EM><BR><I><SPAN
style="FONT-SIZE: 7.5pt; COLOR: black; FONT-FAMILY: Arial">(518) 387-4005, Dial
Comm: 8*833-4005, </SPAN></I><BR><I><SPAN
style="FONT-SIZE: 7.5pt; COLOR: black; FONT-FAMILY: Arial">Cell: (518) 505-7065,
Fax: (518) 387-6981</SPAN></I> </P>
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