On Sunday, October 23, 2016 at 10:09:14 AM UTC-4, c.w.c...@gmail.com wrote:
> Hi Luca,
>
> I assume you mean Slice location as Slice position does not exist, Slice location has an open definition as it is the distance to a unspecified point, with this you could get differences. Even the one you describe I would say.
>
> Secondly why do you calculate the slice position if you have the image position?
>
> Regards,
> Wim
> On Friday, October 21, 2016 at 8:49:17 PM UTC+5:30, Luca Pamparana wrote:
> > I am implementing a method to spatially sort DICOM slices in a volume. The way I am doing it is to sort by the position along the slice normal. This is computed as:
> >
> > slice_normal = [0, 0, 0]
> > dir_cosines = ds[0x0020, 0x0037] # Direction cosines
> > slice_normal[0] = dir_cosines[1] * dir_cosines[5] - dir_cosines[2] * dir_cosines[4]
> > slice_normal[1] = dir_cosines[2] * dir_cosines[3] - dir_cosines[0] * dir_cosines[5]
> > slice_normal[2] = dir_cosines[0] * dir_cosines[4] - dir_cosines[1] * dir_cosines[3]
> >
> > image_pos = ds[0x0020, 0x0032] # IPP
> > distance_along_normal = 0
> > for i in range(len(slice_normal)):
> > distance_along_normal += slice_normal[i] * image_pos[i]
> >
> > Now this value distance_along_normal should be equal to the slice position, except in my case it has the opposite sign. So the slice ordering seems to be reversed than what it should be. So, I must need to take something else into account to correctly compute the slice position.
> >
> > Any ideas?
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