[Insight-users] WG: Origin in shrink image filter wrong?

[Lodron, Gerald]

Maybe that helps:

vtkImageData    image1; //Spacing: (8.5 8.5 4), Origin (-275 -275 -1285), Dimensions(64,64,64), Increments(0,0,0), Extent(0,63,0,63,0,63), Bounds(-275,266,-275,266,-1285,-1033)

vtkImageData    image2; // the same
...
Blabla
...
vtkImageData   shrinkedImage; //Spacing: (17 17 8), Origin (-270 -270 -1283), Dimensions(32,32,32), Increments(0,0,0), Extent(0,31,0,31,0,31), Bounds(-270,262,-270,262,-1283,-1035)

-----Ursprüngliche Nachricht-----
Von: insight-users-bounces at itk.org [mailto:insight-users-bounces at itk.org] Im Auftrag von Lodron, Gerald
Gesendet: Dienstag, 15. Dezember 2009 10:43
An: insight-users at itk.org
Betreff: [Insight-users] Origin in shrink image filter wrong?

Hi

I try to downsample a DICOM image with shrink image filter and i come to no sollution. The problem is that the origin of the result is wrong:

When i load the same DICOM 3D image with the same code and downsample one of them by factor two the images should be aligned, am i right? So when i use the checkerboard the only difference should be the ressolution, am i right? But the images are not aligned so what went wrong? I am really at the end of my vodoo.

I use ITK 3.16.0 with following settings on:
ITK_IMAGE_BEHAVES_AS_ORIENTED_IMAGE
ITK_USE_CENTERED_PIXEL_COORDINATES_CONSISTENTLY
ITK_USE_CONSOLATED_MORPHOLOGY
ITK_USE_OPTIMIZED_REGISTRATION_METHODS
ITK_USE_ORIENTED_IMAGE_DIRECTION
ITK_USE_PATENTED
ITK_USE_REGION_VALIDATION_IN_ITERATORS
ITK_USE_REVIEW
ITK_USE_SYSTEM_GDCM     (i installed and use gdcm 2.0.14)
ITK_USE_TEMPLATE_META_PROGRAMMING_LOOP_UNROLLING

The rest is off.

Here my pseudocode

vtkImageData    image1; //3D image of short
vtkImageData    image2; //the same

//Image1 is exactly the same as image 2, i use vtkCheckerboard to compare them and they are the same

//first i convert both to ITK
Itk::VTKImageToImageFilter<...>::Pointer connector1 = ...::New(); Itk::VTKImageToImageFilter<...>::Pointer connector2 = ...::New();

Connector1->SetInput(...)
...
Itk::OrientedImage<...>::pointer image1ITK; Itk::OrientedImage<...>::pointer image2ITK;

//now i use shrink image filter to downsample one of them

itk::ShrinkImageFilter<>::Pointer filter = itk::ShrinkImageFilter<>::New();
filter->SetInput(image2ITK);
filter->SetShrinkFactor(2);


Itk::OrientedImage<...>::pointer image2ITKSmall = filter->getOutput();


//and back to vtk
Itk::ImageToVTKImageFilter::Pointer c1 = ...::New(); Itk::ImageToVTKImageFilter::Pointer c2 = ...::New();

C1->setInput(image1ITK);
//C2->setInput(image2ITK);              //with that the images are aligned
C2->setInput(image2ITKSmall);           //with that not aligned

//back to vtk and visualize with checkerboard

vtkImageCheckerboard*   Checkerboard= vtkImageCheckerboard::New();

Checkerboard->SetInput(0, C1->getOutput()); SetInput(1, 
Checkerboard->C2->getOutput()); SetNumberOfDivisions(2, 2, 2);

//visualize Checkerboard->getOutput()
...







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