Small diagonal artifact in BlocksOnCylindrical sinograms
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- Dominant language
- C++
- Stars
- 160
- Forks
- 113
- Avg merge
- 12d 15h
- Merged PRs (30d)
- 1
Description
When projecting a cylinder on a BlocksOnCylindrical scanner and comparing the first 90° of the sinogram with the next 90°, then there appears a thin diagonal artifact with approximately 0.1% of the amplitude of the projection data entries.
Code to reproduce:
blah = stir.ProjDataInMemory.read_from_file("scatter_tests/full_size_sino.hs")
bla = stirextra.to_numpy(blah.get_segment_by_sinogram(0))
diff = bla[15,:48,:] - bla[15,48:,:]
plt.figure()
plt.imshow(diff)
plt.colorbar()
where full_size_sino.hs can be created using the InterpolationTests::scatter_interpolation_test_blocks() test in test_interpolate_scatter.cxx by adding a forward projection on the full size scanner definition.
Contributor guide
First steps
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Research direction
Start with the InterpolationTests::scatter_interpolation_test_blocks() test in test_interpolate_scatter.cxx and reproduce the full-size sinogram described in the issue. Use the supplied Python comparison of segment 0 to inspect the diagonal artifact and determine its source. Done means the first and next 90° portions no longer show the reported discrepancy, with the relevant test still passing.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- cpp, python
- Domain
- computer-vision, testing-qa
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 30/100