[vtkusers] 3D image as N cubes

[Francisco Lopez de la Franca]

Hi everybody,
Once I retrieve the list of points (IDs) in an octree region/octant, by
coding

vtkIdTypeArray* points = octree->GetPointsInRegion(i);

I'd like to know the scalar voxel value (0 or 1 since the image is binary)
of every point in the "points" array.
I've tried with "points->GetValue(iterator)" and with "points->GetTuple1()"
but the result is not the expected.

Please, does someone know what I should I do or what am I doing wrong?

Sincerely, thank you very much.
Regards

2015-06-09 23:49 GMT+02:00 Francisco Lopez de la Franca <
franciscolopezdelafranca at gmail.com>:

> Hi again,
> Could anybody tell what is the difference between vtkoctreepointlocator
> and vtkhyperoctree? I am using the former for ceating an octree from an
> image, but i donot know which one is the best. My intention is mainly to
> know how many points there are per octant.
> Thank you very much.
> My best regards.
>
> El miércoles, 3 de junio de 2015, Francisco Lopez de la Franca <
> franciscolopezdelafranca at gmail.com> escribió:
>
>> Thanks a lot.
>> And is there an example on how to traverse the whole octree? I mean, i
>> would like to know how many points there are per octant.
>> And finally, independently on the image, if i create an octree with a
>> fixed level, will the representation be the same? I mean, the same number
>> of octants with the same distribution independently on the image?
>> Thank you very much.
>> My best regards.
>> El 03/06/2015 15:36, "Bill Lorensen" <bill.lorensen at gmail.com> escribió:
>>
>>> This example may help:
>>> http://www.vtk.org/Wiki/VTK/Examples/Cxx/DataStructures/OctreeVisualize
>>>
>>>
>>> On Wed, Jun 3, 2015 at 8:48 AM, Francisco Lopez de la Franca
>>> <franciscolopezdelafranca at gmail.com> wrote:
>>> > Hi.
>>> > I've created an example (see below) but everything is OK except that
>>> the
>>> > output image is not created. I'd be very pleased if someone can help me
>>> > (maybe with an explanatory example or whatever).
>>> >
>>> >     char* filename = new char[255];
>>> >     strcpy(filename, "nifti_image.nii");
>>> >
>>> >     vtkSmartPointer<vtkNIFTIImageReader> reader =
>>> > vtkSmartPointer<vtkNIFTIImageReader>::New();
>>> >
>>> >     reader->SetFileName(filename);
>>> >     reader->Update();
>>> >
>>> >     //Create the octree
>>> >     vtkSmartPointer<vtkOctreePointLocator> octree =
>>> > vtkSmartPointer<vtkOctreePointLocator>::New();
>>> >     octree->SetDataSet((vtkDataSet*) reader->GetOutput());
>>> >     octree->BuildLocator();
>>> >
>>> >     std::cout << "Number of cells in tree: " <<
>>> > octree->GetDataSet()->GetNumberOfCells() << std::endl;
>>> >     std::cout << "Number of points in tree: " <<
>>> > octree->GetDataSet()->GetNumberOfPoints() << std::endl;
>>> >
>>> >     char* outfile = new char[255];
>>> >     strcpy(outfile, "OcTree.vtp");
>>> >
>>> >     vtkSmartPointer<vtkXMLPolyDataWriter> writer =
>>> > vtkSmartPointer<vtkXMLPolyDataWriter>::New();
>>> >     writer->SetInputData((vtkPolyData*) octree->GetDataSet());
>>> >     writer->SetFileName(outfile);
>>> >     writer->Write();
>>> >
>>> >
>>> > 2015-05-29 12:40 GMT+02:00 Francisco Lopez de la Franca
>>> > <franciscolopezdelafranca at gmail.com>:
>>> >>
>>> >> Hi everybody,
>>> >> I'd like to represent a 3D image as a fixed number of cubes, I mean,
>>> >> something like a spatial occupancy matrix in 3D.
>>> >>
>>> >> Could you, please, recommend me a fast way to do it or does it exist
>>> a
>>> >> data structure in VTK to achieve this?
>>> >>
>>> >> I've found the OcTree structure but I donot know if it is valid for
>>> this.
>>> >>
>>> >> Thank you very much.
>>> >> My best regards.
>>> >> /Francisco
>>> >
>>> >
>>> >
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>>>
>>>
>>> --
>>> Unpaid intern in BillsBasement at noware dot com
>>>
>>
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