[Insight-users] A few questions about the DigitallyReconstructedRadiograph1 example

[Chris Turner]

Hi,

i"m interested in the DigitallyReconstructedRadiograph. And have a few
questions:

1. Why is the image getting smaller with a smaller "sid" value. sid is
the distance and in my understanding the larger the distance the
smaller the output picture. (By smaller picture/image I don't mean the
picture itself but the object that is projected to the picture)

2. Rotation: I don't get it.....
I'm using this image: http://www.slicer.org/slicerWiki/images/4/43/MR-head.nrrd

origin:  86.64,-133.92,116.78
Pixels: 256 256 130
spacing: 1 1 1.3

so with:
./DigitallyReconstructedRadiograph1 -o DRR.png -t -214.645, -5.9286,
-32.29  -sid -500 MR-head.nrrd
I get a nice picture from the left.

Now I want to rotate the image to get a picture from his face
(anterior). So I set the center of rotation to: 128 128 68.5
(pixel*spacing/2) the Image center.

But if I change now the rotation angles I can't see anything - just a
black picture.



So maybe somebody can help me?

Thanks,
Chris