[Dcmlib] Re: [vtkusers] voxel's volume

[Jean-Pierre Roux]

Mathieu Malaterre wrote:

>
>> I do agree with Mathieu.
>> You cannot get the voxel Z Size reading just an image.
>> You need 2 images, get the Date Element 0x0020,0x0032 --> Image 
>> Position (Patient), and compute the Z spacing.
>> Mathieu :
>> Don't you think we (I) should add GDCM a method to do that (you pass 
>> the 2 "Image Position (Patient)", and it returns zspacing.
>> My question : I add it on *which* class (noy on File, not on 
>> FileHelper, not on Document ...?)
>
>
> I'll answer that on dcmlib
>
>> --> Probabely a misstyping : Image Position (Patient) is the right 
>> one, isn't it?
>>
>>> Image Orientation (Patient) 
>>
>
> Sorry I was not clear at all... So in summary to compute the zspacing 
> you need:
> * Image Position (Patient)
> * Image Orientation (Patient)  (to get the normal)
>
> The original email with plenty of details can be found at:
> http://www.itk.org/pipermail/insight-users/2003-September/004762.html
>
> And an implementation can be found in 
> gdcm::SerieHelper::ImagePositionPatientOrdering
> (gdcmSerieHelper.cxx)


OK.
As a side effect, gdcm::SerieHelper::ImagePositionPatientOrdering() 
computes now ZSpacing, using IPP anf IOP, according to Jolinda Smith's 
algorithm.
(It's not time consuming, the sorting *is*. And, anyway user would have 
to sort the FileList to compute ZSpacing,.
The pb of using it withing vtkgdcmReader is still pending)
JP

>
> HTH
> Mathieu
>