<div class="gmail_quote">On Fri, Jul 10, 2009 at 12:59 PM, Jochen Cammin <span dir="ltr"><<a href="mailto:jcammin1@jhmi.edu">jcammin1@jhmi.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Should I take the silence on this subject as a sign that it is not possible to initialize the parameters of an optimizer other than zero?</blockquote><div><br>You can initialize Demons registration with an initial deformation field. The API is as simple as :<br>
<br> demonsRegistrationFilter->SetInitialDeformationField( fieldImage );<br><br><br></div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<br>
<br>
Thank you,<br>
Jochen<br>
<br>
<br>
Jochen Cammin wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hello,<br>
<br>
I'm fairly new to ITK and want to use it for 4D image registration. I<br>
modified the example DeformableRegistration2 to my needs (changing the<br>
dimension from 2 to 4) and it works well.<br>
<br>
I assume that the initial deformation parameters are all set to 0. In my<br>
case, however, I do have an estimate for the initial deformation in<br>
terms of an initial motion vector field (a 3D image with vectors as<br>
pixel types). Is it possible to initialize the deformation with this<br>
vector field?<br>
<br>
I saw that other examples (like DeformableRegistration7) explicitly<br>
initialize the deformation parameters with zeros by calling<br>
parameters.Fill( 0.0 ). But it is not obvious to me how I would<br>
translate the vector field into deformation parameters.<br>
<br>
Thank you,<br>
Jochen<br>
<br>
<br>
<br>
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</blockquote></div><br><br clear="all"><br>-- <br>Karthik Krishnan<br>R&D Engineer,<br>Kitware Inc.<br>Ph: 518 881 4919<br>Fax: 518 371 4573<br>