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<DIV>Hi, Luis: </DIV>
<DIV> </DIV>
<DIV> Thanks for your reply. I attach the result for 3D registration for orginal resolution of images and the sub sample version. The sub sample image factor is 2 for x and Y, and 1 for Z. It means that the each slice is half copmared with the original slice. But the number of slices is not changed. </DIV>
<DIV> </DIV>
<DIV> Regarding your question about what components are you using ?<BR><BR> 1) Image modality ?<BR> 2) Transform ?<BR> 3) Optimizer ?<BR> 4) Metric ?<BR> 5) Interpolator ?<BR></DIV>
<DIV>I attach part of my code in python </DIV>
<DIV> </DIV>
<DIV><BR><FONT color=#0000ff>registration = itk.MultiResolutionImageRegistrationMethod[itk.Image[itk.F,3],itk.Image[itk.F,3]].New()<BR>imageMetric = itk.MattesMutualInformationImageToImageMetric[itk.Image</FONT></DIV>
<DIV><FONT color=#0000ff>[itk.F,3],itk.Image[itk.F,3]].New()<BR></FONT></DIV>
<DIV><BR><FONT color=#0000ff>transform = itk.VersorRigid3DTransform.D.New()<BR>finalTransform= itk.VersorRigid3DTransform.D.New()<BR>optimizer = itk.RegularStepGradientDescentOptimizer.New()<BR>interpolator = itk.LinearInterpolateImageFunction[itk.Image[itk.F,3],itk.D].New() <BR></FONT></DIV>
<DIV><FONT color=#0000ff></FONT> </DIV>
<DIV><FONT color=#0000ff> I also attach the result repsectively using the orginal volume and sub sample volume </FONT></DIV>
<DIV><FONT color=#0000ff></FONT> </DIV>
<DIV><FONT color=#0000ff> for orginal volume I get reasonably registered result. the result is </FONT></DIV>
<DIV><FONT color=#0000ff></FONT> </DIV>
<DIV><FONT color=#0000ff>Final Registration Parameters <BR>versor X = -0.001937<BR>versor Y = 0.003333<BR>versor Z = -0.002403<BR>Translation X = -0.250085<BR>Translation Y = -4.207276<BR>Translation Z = -782.659578<BR>Iterations = 45.000000<BR>Metric value = -0.124261</FONT></DIV>
<DIV><FONT color=#0000ff></FONT> </DIV>
<DIV><FONT color=#0000ff>for sub sample volume the registered result is empty, which means only defalut pixel values</FONT></DIV>
<DIV><FONT color=#0000ff>Final Registration Parameters <BR>versor X = 0.000695<BR>versor Y = -0.011173<BR>versor Z = -0.000622<BR>Translation X = -0.034234<BR>Translation Y = -2.751356<BR>Translation Z = -794.621228<BR>Iterations = 45.000000<BR>Metric value = -0.147362</DIV>
<DIV><BR> So I am wondering where goes wrong? Please let me know if there is anything unclear. Thx </DIV>
<DIV> </DIV>
<DIV>Wen </DIV>
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