[Insight-users] registration question

[Ken Urish]

Luis

Thanks for your response. Ive always been impressed by the excellent
support in the itk community.

Indeed, you are right. My z-axis spacing and origin is getting lost.......
Im using dicom so I am surprised this is happening.

When I look at the output of the registered and resampled output of
the moving image - the spacing and origin is identical to the input of
he fixed image. This is expected. I am doing a mattes registration so
my code is similar to the example itk code. I am using the verser
transform.

When I take that identical output registered image and use it as input
for the checkerboard filter program the z-axis origin and spacing are
changed to 0 and 1 respectively.

My registration output image info is collected from the resampled
image just before it is sent to the image series writer using gdcmIO.
The checkerboard input image info is collected just after the input
reader. Thus my registration output writer is somehow loosing this
z-axis info. Im keeping it in dicom so Im stuck on how Im loosing it.

One solution would be to change the spacing and origin on my
checkerboard program. But I would be interested in having this fixed
on the initial registration program. Any thoughts on my error? I
appreciate the help. I included the specific output below.

Thanks
--Ken--


Registration Fixed input image:
  Spacing: [0.3125, 0.3125, 3.48]
  Origin: [-18.1241, -60.8059, 58.0112]
  Direction:
-0.0348995 0 -0.999391
0.999391 0 -0.0348995
0 -1 0

Registration Moving input image:
  Spacing: [0.364583, 0.364583, 0.7]
  Origin: [-3.39372, -70.4365, 70]
  Direction:
-0.0348995 0 -0.999391
0.999391 0 -0.0348995
0 -1 0

Registration OUTPUT Image of the resampled moving image:
  Spacing: [0.3125, 0.3125, 3.48]
  Origin: [-18.1241, -60.8059, 58.0112]
  Direction:
1 0 0
0 1 0
0 0 1


=====================================================================
Output of when the registered images are put straight through a checker filter:

Checker Input image of the registrated output moving image
  Spacing: [0.3125, 0.3125, 1]
  Origin: [-18.1241, -60.8059, 0]
  Direction:
1 0 0
0 1 0
0 0 1

Checker Input image of the fixed
  Spacing: [0.3125, 0.3125, 3.48]
  Origin: [-18.1241, -60.8059, 58.0112]
  Direction:
-0.0348995 0 -0.999391
0.999391 0 -0.0348995
0 -1 0


Checker Output with no resampling
  Spacing: [0.3125, 0.3125, 1]
  Origin: [-18.1241, -60.8059, 0]
  Direction:
1 0 0
0 1 0
0 0 1