<div dir="ltr">Hi has anyone any idea why I obtain this behaviour, is it a limitation of smoothing at every update?<div><br></div><div>Thanks in advance</div><div><br></div><div>Emma<br><div><br></div><div><br></div></div>
</div><div class="gmail_extra"><br><br><div class="gmail_quote">On Wed, Jul 31, 2013 at 9:26 AM, Emma Saunders <span dir="ltr"><<a href="mailto:emmasaunders123@gmail.com" target="_blank">emmasaunders123@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hi everyone,<div><br></div><div>I'm attempting some multi-resolution demons, as input I use an initial affine transform. When monitoring convergence however, I get peaks at every pyramid level (see attached diagram). Is this normal behaviour</div>
<div><br></div><div> my pseudocode looks something like:<br></div><div><br></div><div>//Define Demons filter</div><div><br></div><div> RegistrationFilterType::Pointer filter = RegistrationFilterType::New();<br>
</div><div><br></div><div>//Create initial Affine transform and convert to Displacement field, called AffineField</div><div><br></div><div><div> AffineField=converter->GetOutput();</div><div> </div>
</div><div><div><div> filter->SetInput(AffineField);</div><div> filter->SetStandardDeviations( 0.8);</div></div><div><br></div><div>//use multiResolution</div><div><br></div><div><div> MultiResRegistrationFilterType::Pointer multires = MultiResRegistrationFilterType::New();</div>
<div><br></div><div> multires->SetRegistrationFilter( filter );</div><div> multires->SetNumberOfLevels( 4 );</div><div> multires->SetFixedImage( FixedImage );</div><div> multires->SetMovingImage( MovedImage );</div>
<div> unsigned int nIterations[4] = {100, 100, 50, 50 };</div><div> multires->SetNumberOfIterations( nIterations );</div><div> multires->Update();</div><div><br></div></div><div>Am I correct in setting the initial affine field in this manner, does this set the affine field for the first stage of the pyramid? or is it a case of the affine field being re-applied at every pyramid value and hence peaks in the metric</div>
<div><br></div><div>Thoughts appreciated</div><div><br></div><div>Thanks</div><span class="HOEnZb"><font color="#888888"><div><br></div><div>Emma</div><div><br></div><div><br></div><div><br></div></font></span></div></div>
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