[Insight-users] Problem on PET-CT Registration - Help Needed!!!
cspl
affable@hd2.dot.net.in
Sat, 19 Apr 2003 18:06:06 +0530
Hi Luis,
Thanks for ur mail.
As u said i am printing the initial transform paramters. I get the
following values:-
[1, 0, 0, 1, 70.4192, 75.7447, -188.845, -146.701]
I used "CenteredTransformInitializer" class for initializing the
CenteredAffineTransform.
Even now i get the same error from itk. I tried with different values for
the paremeters but the error doesn't get any affect.
Error is:-
itk::ExceptionObject (0012FD38)
Location: "Unknown"
File:
G:\NEWITKFILES\NewVersionITK7_4_2003\itksrc\Code\Algorithms\itkMattesMutualI
nformati
onImageToImageMetric.txx
Line: 546
Description: itk::ERROR:
MattesMutualInformationImageToImageMetric(00302740): Too many sam
ples map outside moving image buffer: 52 / 1000
Not even one iterations are generated this time also...
What else i have to change the parameters...
Any estimate of suitable parameters...
My data sets are 512x512x1 (0.976562/0.976562 spacing) and 128x128x1
(3.906250/3.906250 spacing). Image type is short.
Please suggest me...
Thanks in advance.
-Regards,
Sateesh.
----- Original Message -----
From: "Luis Ibanez" <luis.ibanez@kitware.com>
To: "cspl" <affable@hd2.dot.net.in>
Cc: <insight-users@public.kitware.com>
Sent: Friday, April 18, 2003 07:11 PM
Subject: Re: [Insight-users] Problem on PET-CT Registration - Help Needed!!!
>
> Hi Sateesh,
>
> If the registration is not performing a single
> iteration then you certainly have an initialization
> problem.
>
>
>
> Things to check for:
>
>
>
> 1) Are you setting the Initial transform parameter ?
>
> Please print out the transform parameters as they
> are just before starting the registration...
> That will throw some light on the problem.
>
>
>
> 2) If you use the CenteredAffineTransform, it is
> important to also use the
>
> CenteredTransformInitializer
>
> Centered transforms are not as intuitive for
> initialization.
>
> Examples are available on the SoftwareGuide
>
> http://www.itk.org/ItkSoftwareGuide.pdf
>
> take a look at Section 7.5.3 starting in
> pdf-page 198
>
> The associated examples are in
>
> Insight/Examples/Registration
>
>
>
> Regards,
>
>
> Luis
>
>
> -------------------
> cspl wrote:
> > Hi Lius,
> > Thanks for ur reply.
> > As u said i added an Observer and tested the registration code. This
time
> > i started with a 2d images. My inputs are one CT (512x512x1) as fixed
and
> > one PET (128x128x1) to the registrations application. Both pixel type is
of
> > short. Pixel spacing of CT is 0.976562\0.976562 and of PET image is
> > 3.906250\3.906250.
> >
> > When i run the application, it is not performing atleast one
iteration
> > and it generates a itk error same as before.
> >
> > itk::ExceptionObject (0012FC2C)
> > Location: "Unknown"
> > File:
> >
G:\NEWITKFILES\NewVersionITK7_4_2003\itksrc\Code\Algorithms\itkMattesMutualI
> > nformati
> > onImageToImageMetric.txx
> > Line: 546
> > Description: itk::ERROR:
> > MattesMutualInformationImageToImageMetric(00302050): Too many sam
> > ples map outside moving image buffer: 0 / 1000
> >
> > I used the following settings:-
> > No. of iterations: 150
> > Translate Scale : 10000
> > Optimizer Scale : 1
> > Max Step Length : 4
> > Min Step Length : 0.01
> > Spatial Samples : 1000
> > Bins : 50
> > No. of levels : 5
> >
> > I am using "CenteredAffineTransform" for transformation. For this i
am
> > shifting the origin to the image center for both the images.
> >
> > I added shrinking factor of 4 for both the images but no change in
the
> > output.
> >
> > What could be the problem??? Is this because of the great change in
the
> > image dimensions?? But when we find the image dimensions in terms of
> > millimeters we get almost same dimensions of both of images (image
> > dimensions x pixel spacing). In this case both are of same size. Then
what
> > could be the problem.
> >
> > I could not able to find a proper values for registration parameters.
> >
> > Please suggest some settings for it.
> >
> > Thanks in advance.
> >
> > -Regards,
> > Sateesh.
> >
> > ----- Original Message -----
> > From: "Luis Ibanez" <luis.ibanez@kitware.com>
> > To: "cspl" <affable@hd2.dot.net.in>
> > Cc: <insight-users@public.kitware.com>
> > Sent: Thursday, April 17, 2003 08:45 PM
> > Subject: Re: [Insight-users] Problem on PET-CT Registration - Help
Needed!!!
> >
> >
> >
> >>Hi Cspl,
> >>
> >>1) Did you plug an Observer to your registration ?
> >>
> >> Are you printing out values of the transform
> >> parameters as the registration progesses ?
> >>
> >> Tracking the evolution of the transform will
> >> give you the indications you need for tunning
> >> parameters.
> >>
> >>2) Whenever you get the exception regarding the
> >> low number of samples, it simply means that
> >> the overlap between the two images is too small.
> >>
> >> In other words, that the transform parameters
> >> diverged and the current transform is mapping the
> >> image too far from the expected position.
> >>
> >> The action to take in this case is to track how
> >> long it took for the transfrom to diverge. For
> >> this you need to solve (1) [add an observer and
> >> print out the transform parameters].
> >>
> >>
> >>3) There is no point in using multiresolution if you
> >> dont set the shrinking parameters. You could in
> >> that case simply use a normal registration with
> >> more iterations.
> >>
> >>
> >>Please add an observer to the registration and track
> >>the evolution of the transform. You may want to take
> >>a look at the examples in
> >>
> >> Insight/Examples/Registration/
> >>
> >>
> >>Note that there are also Tcl versions for some of them.
> >>
> >>
> >> Regards,
> >>
> >>
> >> Luis
> >>
> >>
> >>----------------------
> >>cspl wrote:
> >>
> >>>Hi Luis and all,
> >>> Well back with the registration problem again.
> >>> Let me explain my problem.
> >>> I am using PET and CT images as input to registration. PET as fixed
> >>
> > and
> >
> >>>CT as moving images. Total number of images are 35 in each set. So my
> >>
> > data
> >
> >>>sets are 128x128x35 for PET and 512x512x35 for CT.
> >>>Pixel spacing for CT images are 0.976562\0.976562 and for PET images
are
> >>>3.906250\3.906250.
> >>>Now the parameters for registration are
> >>> No. of iterations: 150
> >>> Translate Scale : 10000
> >>> Optimizer Scale : 1
> >>> Max Step Length : 4
> >>> Min Step Length : 0.01
> >>> Spatial Samples : 1000
> >>> Bins : 50
> >>> No. of levels : 5
> >>> I am not using any shrinking factors in the registration.
> >>
> > SetMinimize()
> >
> >>>method is used in registration process.
> >>>
> >>> The above setting are working for other data sets like mri-mri
> >>>registration.
> >>> These parameters are working for single slice of above data set i.e.
> >>
> > if i
> >
> >>>give 1 PET as fixed and 1 CT as moving image with the above parameters
> >>
> > and
> >
> >>>perform registration it is working good with out any itk error.
> >>>
> >>> But if i give 35 slices it is giving the following error message:-
> >>> itk::ERROR:MattesMutualInformationImageToImageMetic(01A93ED0):
> >>
> > Two
> >
> >>>many samples map outside moving image buffer: 0/1000.
> >>>
> >>> I have tried with different values for the above parameters but still
> >>
> > this
> >
> >>>error is generated.
> >>>
> >>> If u have any idea of parameters for these data sets please suggest
> >>
> > me.
> >
> >>> Please help me in this regard.
> >>>
> >>> Thanks in advance.
> >>>
> >>>-Regards,
> >>> Sateesh.
> >>>
> >>>
> >>>_______________________________________________
> >>>Insight-users mailing list
> >>>Insight-users@public.kitware.com
> >>>http://public.kitware.com/mailman/listinfo/insight-users
> >>>
> >>
> >>
> >>
> >>
> >
> > _______________________________________________
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> > http://public.kitware.com/mailman/listinfo/insight-users
> >
>
>
>
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