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applying transformations to points (implementation)

clintg6
2019-05-26
2019-05-27
  • clintg6

    clintg6 - 2019-05-26

    Hi,

    I'm trying to understand how transformations computed from images can be applied to a point located in the image space but not on the image grid itself. With an affine transform it's simple matrix multiplication with the point but what happens when there is also an inverse warp vector field?

    I guess I don't understand how the transformation itself is applied to floating points in the CSV file that are not in a discrete grid like an image/volume.

    Any help is appreciated!

     
    • Nick Tustison

      Nick Tustison - 2019-05-26

      Displacement fields are stored as ITK images where each voxel stores the displacement (dx, dy, dz) at that physically defined location (per the image header). Linear interpolation is used to define the displacement field at any non-voxel location within the image domain.

       
  • clintg6

    clintg6 - 2019-05-27

    Makes sense now, Thanks!