Problem
I noticed stepping / stair artefacts along curved surfaces in helical reconstructions of Anatomical CTs. These artefacts were reproducible across several CTs and by several people using the codebase.
These artefacts were not present in the helical example provided with the codebase because the CT was a phantom with only straight edges along the Z-axis.
Fix
The fix for this artefact is to flip axis=2 of the re-binned projection data within the function helical_equiAngle as below:
Replace line 177:
Proj = PProj.transpose(1,2,0)
With:
Projflip = np.flip(PProj, axis=2) Proj = Projflip.transpose(1, 2, 0)
Function location:
https://github.com/xcist/main/blob/master/gecatsim/reconstruction/pyfiles/helical_equiAngle.py
Problem
I noticed stepping / stair artefacts along curved surfaces in helical reconstructions of Anatomical CTs. These artefacts were reproducible across several CTs and by several people using the codebase.
These artefacts were not present in the helical example provided with the codebase because the CT was a phantom with only straight edges along the Z-axis.
Fix
The fix for this artefact is to flip axis=2 of the re-binned projection data within the function
helical_equiAngleas below:Replace line 177:
Proj = PProj.transpose(1,2,0)With:
Projflip = np.flip(PProj, axis=2) Proj = Projflip.transpose(1, 2, 0)Function location:
https://github.com/xcist/main/blob/master/gecatsim/reconstruction/pyfiles/helical_equiAngle.py