Fw: [Insight-users] different spacing
Grace Chen
Grace.Chen at swri.ca
Fri Dec 30 16:45:57 EST 2005
Hi there,
After struggling for so long trying to make the multi-modality version of my
program to work using ITK, I think it's not working after all. Is it
because that I am using VersorRigid3DTransform and the
VersorRigid3DTransformOptimizer?
Grace
----- Original Message -----
From: "Grace Chen" <Grace.Chen at swri.ca>
To: "Luis Ibanez" <luis.ibanez at kitware.com>
Cc: <insight-users at itk.org>
Sent: Wednesday, December 28, 2005 2:36 PM
Subject: Re: [Insight-users] different spacing
> Hi Luis,
>
> Sorry, I should have explained a little more.
>
> My program has several levels. The input images were first stored as
> vtkImageData. I moved the fixed image using a vtkTransform object. Then,
I
> used a lower level program which converts these vtkImageData to ImageData
in
> ITK and perform registration using ITK.
>
> The ouput of the optimizer seems to improve the image. I use
> MattesMutualInformationImageToImageMetric. And the ouput of the first and
> last 10 interations are listed as followed:
>
> [optimizer->GetCurrentIteration() , optimizer->GetValue() ,
> optimizer->GetCurrentPosition()]
> 0 -0.180789 [-0.00372431, -0.00216522, -0.00342151, 0.0378279, -0.24234,
> 0.763643]
>
> 1 -0.188343 [-0.00466395, -0.0035364, -0.00456701, 0.158607, -0.401006,
> 0.778505]
>
> 2 -0.189109 [-0.00576653, -0.00498698, -0.00826052, 0.303473, -0.53851,
> 0.784736]
>
> 3 -0.191558 [-0.00700445, -0.00593562, -0.00978375, 0.433646, -0.690175,
> 0.790528]
>
> 4 -0.19593 [-0.0078935, -0.00709936, -0.0107574, 0.591992, -0.811806,
> 0.801494]
>
> 5 -0.197633 [-0.00820251, -0.00741444, -0.0104682, 0.728001, -0.955385,
> 0.831249]
>
> 6 -0.198881 [-0.00741882, -0.00554459, -0.0136817, 0.88545, -1.0598,
> 0.89643]
>
> 7 -0.200073 [-0.00726651, -0.0062833, -0.0140401, 0.985172, -1.22836,
> 0.936929]
>
> 8 -0.201326 [-0.00560797, -0.0076424, -0.0215794, 1.14407, -1.33802,
> 0.98674]
>
> 9 -0.203174 [-0.00389283, -0.00771673, -0.0122035, 1.06042, -1.38851,
> 0.996157]
>
> 10 -0.204234 [-0.00378966, -0.0086788, -0.0158924, 1.04266, -1.48046,
> 1.0304]
>
> ......
>
> 190 -0.211569 [0.00630339, -0.00207671, -0.00499892, 1.33912, -3.38962,
> 2.04202]
>
> 191 -0.211627 [0.00623288, -0.00207366, -0.00491154, 1.34527, -3.39987,
> 2.04566]
>
> 192 -0.211695 [0.0062031, -0.00205791, -0.00481467, 1.35246, -3.40914,
> 2.04997]
>
> 193 -0.211739 [0.00619409, -0.00206643, -0.00479264, 1.359, -3.41882,
> 2.05441]
>
> 194 -0.211778 [0.00619392, -0.00206125, -0.00470146, 1.36589, -3.42833,
> 2.05869]
>
> 195 -0.211825 [0.00620295, -0.00204558, -0.00465544, 1.37306, -3.43779,
> 2.06261]
>
> 196 -0.211863 [0.00621339, -0.00200221, -0.00454069, 1.37962, -3.44758,
> 2.06679]
>
> 197 -0.211899 [0.00622509, -0.00194811, -0.00455557, 1.38273, -3.45872,
> 2.07151]
>
> 198 -0.211928 [0.00621682, -0.0018781, -0.00455407, 1.38537, -3.47006,
> 2.07607]
>
> 199 -0.211961 [0.00616729, -0.00182871, -0.00457491, 1.3884, -3.48145,
> 2.08022]
>
>
>
> Grace
>
>
>
> ----- Original Message -----
>
> From: "Luis Ibanez" <luis.ibanez at kitware.com>
> To: "Grace Chen" <Grace.Chen at swri.ca>
> Cc: <insight-users at itk.org>
> Sent: Wednesday, December 28, 2005 2:11 PM
> Subject: Re: [Insight-users] different spacing
>
>
> >
> > Hi Grace,
> >
> >
> > * Did your registration converged ?
> >
> >
> > * Could you please post the output of the Command/Observer
> > class that you connected to the optimizer ?
> >
> >
> > * Why is that you end up with a vtkTransform
> > if you are doing registration with ITK ?
> >
> >
> >
> > Please let us know,
> >
> >
> > Thanks
> >
> >
> > Luis
> >
> >
> >
> > -----------------
> > Grace Chen wrote:
> > > Hi Luis,
> > >
> > > Thanx for the reply. I know the registration should have been done in
> the
> > > physical space. Even if the viewer I use is a naive viewer, after I
> apply
> > > the registration transform and then I scale the image, both images
(now
> look
> > > approximiatly of the same size) should look aligned too, am I correct?
> But
> > > that's not the case for me.
> > >
> > > By looking at the result of the registration, I notice that the
> translation
> > > is ( 1.3884, -3.48145, 2.08022) which is not the movement I simulated
> i.e.
> > > through the call transform->Translate(5, -25, 0).<'transform' is a
> > > vtkTransform.>
> > >
> > > Grace
> > >
> > > ----- Original Message -----
> > > From: "Luis Ibanez" <luis.ibanez at kitware.com>
> > > To: "Grace Chen" <Grace.Chen at swri.ca>
> > > Cc: <insight-users at itk.org>
> > > Sent: Wednesday, December 28, 2005 1:32 PM
> > > Subject: Re: [Insight-users] different spacing
> > >
> > >
> > >
> > >>Hi Grace,
> > >>
> > >>Please read with more attention the "Image Registration" Chapter
> > >>of the ITK Software Guide.
> > >>
> > >>
> > >>If the two images are taken from the same patient and the image
> > >>spacings are set correctly by the scanner, you *should not need*
> > >>to do *any scaling* when registering the images.
> > >>
> > >>
> > >>The fact that the images look of different sizes in your screen
> > >>just shows that you are using a poor image viewer.
> > >>
> > >>
> > >>You are probably comparing the images based on their number of
> > >>pixels instead of based on their physical extent in space.
> > >>
> > >>
> > >>
> > >>Please study Figure 8.7 in pdf-page 358.
> > >>
> > >>
> > >>The Transfrom that ITK compute is the one that maps the *physical*
> > >>space of one image into the *physical* space of the other image.
> > >>
> > >>
> > >>In that context, if the patient is the same, you shouldn't need
> > >>any scaling unless the head of the patient if physically shrinking
> > >>or expanding between the time of acquiring both scans. (hopefully
> > >>that doesn't happen in any hospital).
> > >>
> > >>
> > >>The transformations from the discrete image grid and the physical
> > >>space are done using the origin and spacing. (Transform T1 and T2
> > >>in Figure 8.7).
> > >>
> > >>
> > >>The transform that ITK computes for you is the "Space Transform".
> > >>
> > >>Please read Section 8.3, from the ITK Software Guide
> > >>
> > >>
> > >>and also read the Tutorial
> > >>
> > >>http://wiki.na-mic.org/Wiki/images/b/ba/Insight-Registration.ppt
> > >>
> > >>
> > >>
> > >> Regards,
> > >>
> > >>
> > >> Luis
> > >>
> > >>
> > >>
> > >>------------------
> > >>Grace Chen wrote:
> > >>
> > >>>Hi there,
> > >>>
> > >>>I am trying to perform multi-modality registration for two volumes.
> The
> > >>>two image data have different physical attributes, etc.
> > >>>different origin, spacing and dimension (so, on the screen, one looks
> > >>>bigger than the other). I simulated a movement (e.g. a translation
(5,
> > >>>-25, 0) in the fixed image. However, when the registration program
> > >>>returns, the final transform matrix is
> > >>>
> > >>>
> > >>> 0.999951 0.00912699 -0.00371374 1.3884
> > >>>
> > >>>-0.0091721 0.999882 -0.0123175 -3.48145
> > >>>
> > >>>0.00360089 0.0123509 0.999917 2.08022
> > >>>
> > >>>0 0 0 1
> > >>>
> > >>>This result is wrong, isn't it? Does the registration program scale
> the
> > >>>images before aligning them? What's going on?
> > >>>
> > >>>Thanx!
> > >>>
> > >>>Grace
> > >>>
> > >>>
> > >>>
> > >>>
> >
>
>>>------------------------------------------------------------------------
> > >>>
> > >>>_______________________________________________
> > >>>Insight-users mailing list
> > >>>Insight-users at itk.org
> > >>>http://www.itk.org/mailman/listinfo/insight-users
> > >>
> > >
> > > _______________________________________________
> > > Insight-users mailing list
> > > Insight-users at itk.org
> > > http://www.itk.org/mailman/listinfo/insight-users
> > >
> > >
> >
> > _______________________________________________
> > Insight-users mailing list
> > Insight-users at itk.org
> > http://www.itk.org/mailman/listinfo/insight-users
> >
>
> _______________________________________________
> Insight-users mailing list
> Insight-users at itk.org
> http://www.itk.org/mailman/listinfo/insight-users
>
More information about the Insight-users
mailing list