<DIV>Hi Luis,</DIV>
<DIV>Thanks for your suggestion.</DIV>
<DIV>I noticed the difference between SPM and ITK.</DIV>
<DIV><BR> </DIV>
<DIV>I have another question</DIV>
<DIV>Do you think the transform parameter obtained from ITK by using different interpolators will be exactly the same or not?</DIV>
<DIV>for example use linear interpolator and B-Spline interpolator.</DIV>
<DIV> </DIV>
<DIV>Best regards,</DIV>
<DIV>Yu Qi</DIV>
<DIV> </DIV>
<DIV><BR><B><I>Luis Ibanez <luis.ibanez@kitware.com></I></B> 写道:</DIV>
<BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid"><BR>Hi Yu,<BR><BR>It seems that thanks to your detailed description, you<BR>provided the answer to your problem in your own message:<BR><BR><BR>"> But SPM integrates spacing info into the rotation 3X3 matrix."<BR><BR><BR>This seems to be the key to the problem that you are facing.<BR><BR><BR><BR>ITK *DOES NOT* incorporates the compensation for pixel spacing<BR>into the Transform that results from the registration. The<BR>reason is that image registration in ITK is done in physical<BR>units, not in the image grid.<BR><BR>You will find a detailed description of this issue in the<BR>ITK Software Guide<BR><BR>http://www.itk.org/ItkSoftwareGuide.pdf<BR><BR><BR>Section 8.3.2 "Registration is done in Physical Space"<BR>pdf-page 319.<BR><BR><BR><BR><BR>Regards,<BR><BR><BR><BR>Luis<BR><BR><BR><BR>----------------------------------<BR>Yu Qi wrote:<BR><BR>> Hi Luis,<BR>> <BR>> Thank
you!<BR>> <BR>> In SPM, the equations to transform the moving image is as follows<BR>> x1=R00*x+R01*y+R02*z+Trans0<BR>> y1=R10*x+R11*y+R12*z+Trans1<BR>> z1=R20*x+R21*y+R22*z+Trans2<BR>> <BR>> But SPM integrates spacing info into the rotation 3X3 matrix.<BR>> <BR>> I compared the result from ITK and the one from SPM,<BR>> I found ITKrotation*ITKspacing is very close to the Ratation matrix in <BR>> SPM and the translations are also very close.<BR>> <BR>> But I can not obtain a good transform in SPM using ITK result.<BR>> Do you think there will be other reasons for this? like the <BR>> interpolation method (default setting in SPM is linear and I use linear <BR>> in ITK)?<BR>> <BR>> Best regards,<BR>> Yu Qi<BR>> <BR>> <BR><BR><BR><BR></BLOCKQUOTE><p><br><hr size=1><b>Do You Yahoo!?</b><br>
<a href="http://music.yisou.com" target=blank>150万曲MP3疯狂搜，带您闯入音乐殿堂</a><br><a href="http://image.yisou.com" target=blank>美女明星应有尽有，搜遍美图、艳图和酷图</a><br>
<a href="http://cn.rd.yahoo.com/mail_cn/tag/1g/*http://cn.mail.yahoo.com/event/mail_1g/" target=blank>1G就是1000兆，雅虎电邮自助扩容！</a>