CODEWITHSUNDEEP
vtk
Yangfan Liu
Yangfan Liu

Reputation: 1

How to get the world coordinates using VTK voxel index?

I’m a beginner of ITK and VTK.Now I want to use the 3D region growing algorithms to segment specific tissues.I have finished the vulume rendering and could get the voxel index by using vtkImagePlaneWidget.But How to get the world coordinate of the index?

vtkImagePlaneWidget

Upvotes: 0

Views: 808

Answers (2)

gWERR
gWERR

Reputation: 1

Other way to do this: if you have a image volume or 3D image with index (i,j,k). You can get the world coordinates (x,y,z) with:

xo,yo,zo = vtk_volume.GetOrigin()
xs,ys,zs = vtk_volume.GetSpacing()
x = xo + i*sx
y = yo + j*sy
z = zo + k*sz

Upvotes: 0

Gabsha
Gabsha

Reputation: 71

vtkImageData exposes a method called TransformIndexToPhysicalPoint which converts voxel indices to world coordinate.

Called from python, it looks something like this

import vtk

img = vtk.vtkImageData()
img.SetDimensions([256,256,256])
img.SetSpacing([0.5,0.5,0.5])
img.SetOrigin([100,100,100])

physical_coord = [0,0,0] # Placeholder
index_coord = [128,128, 128]
img.TransformContinuousIndexToPhysicalPoint(index_coord, physical_coord)

assert tuple(phyiscal_coord) == (164,164,164)

Upvotes: 0

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