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<DIV><FONT face=Arial size=2>Dear insight users,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I currently try to register two 3D images (CT
and MR)</FONT></DIV>
<DIV><FONT face=Arial size=2>by using mutual information as metric.</FONT></DIV>
<DIV><FONT face=Arial size=2>The images have a size of approx. 255 * 290 * 75
slices each (MR perhaps even more).</FONT></DIV>
<DIV><FONT face=Arial size=2>Although I use a very simple transformation
(translation) and a graddescent</FONT></DIV>
<DIV><FONT face=Arial size=2>optimizer, one iteration of the optimizer takes
more than 1.5h.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Is this a common time for images of this
size???</FONT></DIV>
<DIV><FONT face=Arial size=2>The metric uses 60000 spatial samples.</FONT></DIV>
<DIV><FONT face=Arial size=2>I thougt about using BSpline transform in the
next step of the registration</FONT></DIV>
<DIV><FONT face=Arial size=2>with MI metric too, but I think I can forget to do
this, if I have to deal with 3000 Parameters</FONT></DIV>
<DIV><FONT face=Arial size=2>to be optimized!</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Regards,</FONT></DIV>
<DIV><FONT face=Arial size=2>Markus</FONT></DIV>
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