[Insight-users] mi registration problem

[Miller, James V (Research)]

The pattern intensity metric is supposedly robust to devices in the
field.  It uses a non-quadratic error term so the mismatch of the bar 
to CT should not affect the alignment. This metric allows the mismatch 
of intensities can be regional.  MI requires a globally consistent mapping
of intensities.

Jim



> -----Original Message-----
> From: Dill, John [mailto:john-dill at uiowa . edu]
> Sent: Wednesday, October 08, 2003 11:38 AM
> To: 'insight-users at itk . org'
> Subject: [Insight-users] mi registration problem
> 
> 
> I have been having a problem with registering portfilm and 
> drr images.  In
> my case, the algorithm registers the lateral projections just 
> fine, but in
> ap cases, I get mis-registrations.  The problem seems to be 
> from the fact
> that when the patient is on the treatment table, there is a metal bar
> attached to the table which is present in the portfilm, but 
> not in the CT,
> so the DRR doesn't have the corresponding bar in its 
> projection.  The bar
> shows up as roughly 10-15 pixels wide, and as tall as the 
> image.  I have
> tried some different filtering ideas, but can not come up with a good
> registration.  Does anyone have ideas on how to reduce this 
> bar's effects
> (automatically if possible)?
> 
> Thanks,
> John
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