[Insight-users] problems on deformable registration 8

[Sean lee]

Hi, Luis,
Thank you for your reply.
I have 2GB RAM. Here is the error message if I run more than 62 slices: Unhandled exception at 0x7c812afb in RegTest.exe: Microsoft C++ exception: itk::InvalidRequestedRegionError at memory location 0x0013fbbc..
My CT volumes are liver images from two different phases. 
I also did another test on these two volumes by switch them (switch fixed and moving volumes). If I run 62 slices,, it would come with same memory problem (see above error message). This time if I run 60 slices, it would reach "CONVERGENCE: REL_REDUCTION_OF_F <= FACTR*EPSMCH" after one iteration; but it seems 59 slices allow me to run 34 iterations and gave me a good result.
So, it seems the good results came with "reach Projected Gradient Tolerance". If it reaches "CONVERGENCE: REL_REDUCTION_OF_F <= FACTR*EPSMCH" first, it come with a "bad" result. How can I control this situation?
Thanks.
Sean
> Date: Wed, 8 Jul 2009 17:39:25 -0400
> From: luis.ibanez at kitware.com
> To: kevinseanlee at live.com
> CC: insight-users at itk.org
> Subject: Re: [Insight-users] problems on deformable registration 8
> 
> 
> Hi Sean,
> 
> This is very suspicious.
> 
> 
> A) your images do not seem to be that big...
> 
>     One image of:
> 
>       64 slices of 256 x 256 in 16bits
> 
>     will take 8 Mb
> 
> 
>     How much RAM do you have ?
> 
> 
> B) Just removing one slice (out of 60) from your
>     dataset shouldn't lead the registration to
>     behave differently.
> 
> 
>     Unless...
> 
>     There is some special content in that slice...
> 
>     Are any objects in Slice 60 that have very
>     different intensities to those objects visible
>     in slice 59  ?
> 
> 
> ...and...
> 
> 
> C) How are you removing that slice ?
> 
>     Are you using a region of interest extraction first ?
> 
> 
> 
> 
> Please let us know,
> 
> 
>      Thanks
> 
> 
> 
>          Luis
> 
> 
> 
> ---------------
> Sean lee wrote:
> > Hello,
> > 
> > I am trying to use the example of deformable registration 8 on two ct 
> > image volumes (64 256X256 slices). The problem is If i use more than 62 
> > slices, I would have memory problem; I run 60 slice, I got a perfect 
> > results with 20 iterations; but if I run 59 slices, it only run one 
> > iteration and reaches "CONVERGENCE: REL_REDUCTION_OF_F <= FACTR*EPSMCH". 
> > I tried to reduce the Cost Function Convergence Factor to 1e+1 and it 
> > still comes same results. What could be the problem and any suggested 
> > solutions? Thanks. Sean
> > > 
> > 
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