[vtkusers] Surface registration of two data sets, are there any vtk algorithms?

[George Kamucha]

Thanks a lot Tim for the code, I am going to try it with my data. It would really be great if a vtk
class existed for this application and I really appreciate your efforts in this. I will inform you
of any progress I make with this code. Wish you a merry X-mas too!

Best regards

George

> Message: 16
> Date: Thu, 14 Dec 2000 11:41:59 +0000
> To: vtkusers at public.kitware.com
> From: Tim Hutton <T.Hutton at eastman.ucl.ac.uk>
> Subject: Re: [vtkusers] Re: Surface registration of two data sets, are
> there any vtk         algorithms?
>
> George, to save you some time, here are more details of the code I'm using
> at the moment. I'm mailing this to the group in the hope that someone will
> do the boring work of getting this into a new vtk class, I'm off on holiday
> tomorrow, if no-one has done it by the new year I guess I'll have to do it
> myself. ;)
>
> - Given 2 vtkPolyData's: 'mesh' and 'target', create a vtkCellLocator for
> the target:
>
> vtkCellLocator *locator = vtkCellLocator::New();
> locator->SetDataSet(target);
> locator->SetNumberOfCellsPerBucket(1);
> locator->BuildLocator();
>
> - Create the transform classes (will be reused on each iteration):
>
> vtkLandmarkTransform *matcher = vtkLandmarkTransform::New();
> vtkTransformPolyDataFilter *transformer = vtkTransformPolyDataFilter::New();
>
> - Create a replacement set of points for the vertices of the moving mesh:
>
> vtkPoints *points = vtkPoints::New();
> points->SetNumberOfPoints(mesh->GetNumberOfPoints());
>
> - Iterate through this loop:
>
> bool converged_yet=false;
> do {
>
>         // fill 'points' with the closest points to each vertex in the template mesh
>         int cellId,subId;
>         float dist2;
>         for(int i=0;i<mesh->GetNumberOfPoints();i++)
>         {
>
> locator->FindClosestPoint(mesh->GetPoints()->GetPoint(i),points->GetPoint(i)
> ,cellId,subId,dist2);
>         }
>
>         // move mesh to best match the target
>         matcher->SetSourceLandmarks(mesh->GetPoints());
>         matcher->SetTargetLandmarks(points);
>         transformer->SetTransform(matcher);
>         transformer->SetInput(mesh);
>         transformer->Update();
>         mesh->SetPoints(transformer->GetOutput()->GetPoints());
>         mesh->Modified();
>
>         // need some check for convergence here
>         converged_yet = ...
>         // (I'm just running 100 iterations for now)
>
> } while(!converged_yet);
>
> Of course there's lots missing but this is the basic core of the algorithm
> as might be implemented in VTK. The actual ICP algorithm has lots of nice
> ways of dealing with the bits of the surface that don't match but you might
> not need them.
>
> Merry Christmas one and all! - said Tiny Tim.
>
> At 09:31 14/12/00 +0300, you wrote:
> >Hi Tim,
> >Thanks a lot for your useful information,  I will try to apply the two
> classes.
> >
> >Best regards
> >George
> >
> >>
> >>
> >> Date: Wed, 13 Dec 2000 11:11:49 +0000
> >> To: vtkusers at public.kitware.com
> >> From: Tim Hutton <T.Hutton at eastman.ucl.ac.uk>
> >> Subject: Re: [vtkusers] Surface registration of two data sets, are
> >> there any vtk algorithms?
> >>
> >> Aha! Was wondering if anyone else needed this.
> >>
> >> The standard way to match two surfaces would have to be iterative closest
> >> point (ICP). The core of the algorithm is to match each vertex in one
> >> surface with the closest surface point on the other, then apply the rigid
> >> transformation that moves one surface to best match the other. This has to
> >> be iterated to get proper convergence of the surfaces.
> >>
> >> VTK is ideal for this kind of stuff, the two classes vtkCellLocator and
> >> vtkLandmarkTransform in particular do all the hard work for you. If there
> >> is a desire, I'd be happy to help with a vtkIterativeClosestPointTransform
> >> (or whatever) class - trouble is, it's not really visualization, more
> >> computational geometry; there's an issue of whether to keep bloating VTK
> >> with these things.
> >>
> >> Tim.
> >>
> >> At 10:13 13/12/00 +0300, you wrote:
> >> >I am wondering whether there could be a program written in vtk which can
> >> determine the transformation
> >> >between two surface data sets. I have two surface data sets of a bone
> >> which I have generated using different
> >> >
> >> >imaging modalities: one from CT-imaging and the other from laser radar
> >> imaging. I would like to obtain the
> >> >transformation (rotation and translation) between the two data sets using
> >> surface matching techniques.
> >> >Anybody out there who knows where I can obtain such surface matching
> >> algorithms? Your assistance will be
> >> >highly appreciated.
> >> >
> >> >Best regards
> >> >
> >> >George kamucha
> >> >Department of High Frequency Engineering
> >> >University of Kassel
> >> >Wilhelmshoeher Allee 73
> >> >34121 Kassel
> >> >Germany
>