[ITK-users] Interpolation, Requested Region, and periodic signals

[Cyril Mory]

Hi ITK users,

I am computing 4D images of the breathing thorax. The first 3 dimensions 
are the spatial ones, the last one is the respiratory phase (breathing 
is considered periodic). At some point in the algorithm, I have to 
interpolate a 4D sequence of volumes along the phase dimension to create 
a 3D volume. I use a custom interpolation filter, not the ITK one, with 
the GenerateData implemented in CUDA (I work on RTK, a library based on 
ITK that has support for CUDA).

I would like to request only the required data for this interpolation, 
in order to avoid keeping the whole 4D sequence in GPU memory. Most of 
the time, the two 3D volumes between which I need to interpolate are 
consecutive in the 4D sequence, so it is easy to write a 
GenerateInputRequestedRegion() that requests a 4D region of size 2 on 
the fourth dimension.
But when interpolating between the last and the first 3D volumes of the 
sequence (remember : breathing is periodic), the only ITK::ImageRegion 
that contains them both is the whole 4D sequence. I would like to avoid 
loading the whole 4D sequence.

Any suggestions on how I could do that ?

Best regards,
Cyril