<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
<META content="MSHTML 6.00.2800.1515" name=GENERATOR></HEAD>
<BODY>
<DIV><FONT face=Arial size=2><SPAN
class=472375612-30092005><STRONG>Tanya,</STRONG></SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=472375612-30092005><STRONG></STRONG></SPAN></FONT> </DIV>
<DIV><FONT><SPAN class=472375612-30092005><FONT face=Arial
size=2><STRONG>ImageRegistration8 uses MeanSquaresImageToImageMetric and
VersorRigid3DTransform for registration. This combination may work well for
images acquired for the same subject using the same modality, in which
case, two images can be aligned using a rigid transform (same
subject), and corresponding points in the moving image and the fixed
image have same intensity (same modality). For your application, you are
registering a PET image with an MRI image. You may want to try one of the
mutual information based image to image metric to get more accurate result, such
as </STRONG></FONT>
<P><FONT face=Arial><FONT
size=2><STRONG>itkNormalizedMutualInformationHistogramImageToImageMetri<SPAN
class=472375612-30092005>c </SPAN></STRONG><SPAN
class=472375612-30092005><STRONG>or </STRONG></SPAN></FONT></FONT><SPAN
class=472375612-30092005><FONT face=Arial
size=2><STRONG>itkMattesMutualInformationImageToImageMetric</STRONG></FONT></P>
<P><STRONG><SPAN class=472375612-30092005><FONT face=Arial size=2>There are a
few examples showing how to used these metrics.</FONT></SPAN></STRONG></P>
<P><STRONG><SPAN class=472375612-30092005><FONT face=Arial size=2>The
MeanSquaresImageToImageMetric is also one of the reasons that the program
takes long time to run, since at each iterattion, it transforms and interpolates
ALL points in the Fixed image region in order to compute the metric. When you
use itkNormalizedMutualInformationHistogramImageToImageMetri<SPAN
class=472375612-30092005>c </SPAN><SPAN class=472375612-30092005><STRONG>or
</STRONG></SPAN><SPAN class=472375612-30092005><FONT face=Arial
size=2><STRONG>MattesMutualInformationImageToImageMetric, you can always control
the running time by setting the number of samples in the fixed image region for
metric computation.</STRONG></FONT></SPAN></FONT></SPAN></STRONG></P>
<P><STRONG><SPAN class=472375612-30092005><FONT face=Arial size=2>If you still
want to use <SPAN class=472375612-30092005><FONT face=Arial
size=2><STRONG>ImageRegistration8, you can use the PET image (which has fewer
voxels than the MRI image) as the fixed image to cut down the running
time.</STRONG></FONT></SPAN></FONT></SPAN></STRONG></P>
<P><STRONG><SPAN class=472375612-30092005><FONT face=Arial size=2><SPAN
class=472375612-30092005>Xiaodong</SPAN></FONT></SPAN></STRONG></P></SPAN></SPAN></FONT><FONT
face=Tahoma size=2>-----Original Message-----<BR><B>From:</B>
insight-users-bounces+taox=research.ge.com@itk.org
[mailto:insight-users-bounces+taox=research.ge.com@itk.org]<B>On Behalf Of
</B>Tanya S<BR><B>Sent:</B> Thursday, September 29, 2005 11:34 PM<BR><B>To:</B>
Luis Ibanez; insight-users@itk.org<BR><B>Subject:</B> Re: [Insight-users]
ImageRegistration8 takes 2 hours 45 menit!<BR><BR></FONT></DIV>
<BLOCKQUOTE>
<DIV>Hi Luis,</DIV>
<DIV> </DIV>
<DIV>I have tried to run imageRegistration8 for Release version and it took 21
minutes :((. My machine spesification and the image size are the same as
what I wrote on my last email (email attached). </DIV>
<DIV> </DIV>
<DIV>Thanks beforehand for your answer.</DIV>
<DIV> </DIV>
<DIV>Best regards,</DIV>
<DIV>.Tanya.<BR><BR><B><I>Tanya S <tanya_lll@yahoo.com></I></B>
wrote:</DIV>
<BLOCKQUOTE class=replbq
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">
<DIV><BR>
<BLOCKQUOTE class=replbq
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">
<P>Hi Luis, thanks a lot for answering my question.</P>
<P>Below are the detail of my machine:<BR><BR><EM>1) In what type of
machine did you run this code ?</EM></P>
<P>Intel Pentium 4 2.4 GHz<BR><EM>2) What operating system ?</EM></P>
<P>Windows 2000<BR><EM>3) What compiler ?</EM></P>
<P>Microsoft Visual C++ 6.0</P>
<P><EM>4) Did you build it for "Release" ?</EM></P>
<P>No, it was Debug version.<BR></P>
<P>The size of the images are :<BR>- MRI image</P>
<P>Dimension:256, 256, 168</P>
<P>Voxel size(mm): 0.86,0.86, 1.5</P>
<P>The .img file is 21,500 KB</P>
<P><BR>- PET image</P>
<P>Dimension: 128, 128, 94</P>
<P>Voxel size(mm): 2.0, 2.0, 3.0</P>
<P>the .img file is 3,000 KB<BR></P>
<P>Maybe I should try for Release. I ll tell you how it works in
Release version.<BR></P>
<P>Thanks again,</P>
<P>.Tanya.<BR><BR>-----------------<BR>Tanya S wrote:<BR>> Dear
all,<BR>> <BR>> I would like to start doing registration using ITK.
I run the sample: <BR>> ImageRegistration8 for registering two Analyze
head images, i.e:<BR>> - MRI image(Dimension:256, 256, 168 and Voxel
size(mm): 0.86,0.86, 1.5)<BR>> - PET image(Dimension: 128, 128, 94 and
Voxel size(mm): 2.0, 2.0, 3.0)<BR>> <BR>> The registration process
takes around 2 hours and 45 minutes with <BR>> non-accurate result
:(.<BR>> <BR>> I would like to ask why does it take so long and how
to make it faster?<BR>> <BR>> Any hint would be really
appreciated.<BR>> <BR>> Best regards,<BR>> .Tanya.<BR>>
<BR><BR></P></BLOCKQUOTE></DIV>
<P>
<HR SIZE=1>
Yahoo! for Good<BR><A href="http://store.yahoo.com/redcross-donate3/">Click
here to donate</A> to the Hurricane Katrina relief effort.
_______________________________________________<BR>Insight-users mailing
list<BR>Insight-users@itk.org<BR>http://www.itk.org/mailman/listinfo/insight-users<BR></BLOCKQUOTE>
<P>
<HR SIZE=1>
Yahoo! for Good<BR><A href="http://store.yahoo.com/redcross-donate3/">Click
here to donate</A> to the Hurricane Katrina relief effort.
</BLOCKQUOTE></BODY></HTML>