[Rtk-users] Volume error with fdkrtk backprojecting Polynomial corrected logged Projection Images.

[Steven Pollmann]

Hey RTK Users, 

I'm having an issue with rtkfdk output that I am trying to track down. I'm using logged projection images that have had a polynomial-based correction applied to them.  Every voxel in the output 3D mhd file (float) has a floating point value of 7FFFFFFF which, I believe is the largest 32bit float representation.  The input projection images look fine when I open them with VolView (having values ranging from -0.3(air) to 45.0 (metal screw)). The original non-corrected projections (having values ranging from -0.02(air) to 2.88(screw)) work with rtkfdk to produce a nice looking volume, so there is something I am missing.  Using in-house software, this polynomial corrected projection data reconstructs on a CPU-based implementation fine, however both CPU and CUDA backprojections from rtkfdk will not produce a valid 3d Volume for me.  If anyone has insight into what change in the projection data may cause this, that would be appreciated.  The dataset isn't proprietary (it is a scan of a 4x4x4 Rubiks Cube), and so I can send files to some online storage, if needed. (It is around 2GB of projection data...).

Thanks again,
Steve