[Insight-users] Assign world coordinates to spatial objects

[Luis Ibanez]

Hi Patrik,

Please look at the examples:

    Insight/Examples/Filtering/
           SpatialObjectToImage1.cxx
           SpatialObjectToImage2.cxx

They illustrate the use of the GroupSpatialObject,
and how to setup the relative coordinates of
several SpatialObjects.

You should fines lines 230-250 to be very interesting.
In particular

  ellipse->SetObjectToParentTransform( transform1 );


BTW: You don't need to use the SceneSpatialObject.
The GroupSpatialObject should be enough for what
you are doing.


You may be interested, as well, in the examples:

   Insight/Examples/Registration/
            ModelToImageRegistration1.cxx
            ModelToImageRegistration2.cxx


    Regards,


         Luis


--------------------------------------------------------------
On Thu, Apr 29, 2010 at 4:47 PM, Patrik Brynolfsson
<patrik.brynolfsson at radfys.umu.se> wrote:
> Hello,
> I've been trying to figure this out but I can't seem to get it right, but I
> assume this is a very simple problem to solve. I am trying to evaluate noise
> in CT images using a phantom for which I know the dimensions and positions
> of 20 spheres of different sizes. My idea was to construct a group of
> spatial objects (EllipseSpatialObject) and connect it to a high dose
> reference image which I can use to register other images to, and then apply
> the transform to the spatial objects to find their positions i the new
> image.
> First I create the EllipseSpatialObjects and connect them to a
> GroupSpatialObject so that they have the correct positions to each other. I
> also know the world coordinates of the spheres in the reference image, but I
> wonder how I can place the GroupSpatialObject to match the spheres in the
> image. I have a couple of different reference image series, and when I apply
> the SpatialObjectToImageFilter and put in the reference image's direction,
> spacing and origin I get very different results for different images, which
> really confuses me. So, my two questions are:
>
> How do I assign world coordinates to the spatial objects?
> What is the difference between SceneSpatialObject and GroupSpatialObject?
> Which one do you recommend for this problem?
>
> Thanks in advance!
> ---
> Patrik Brynolfsson
>
>
>
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