scatter simulation/estimation recommendations for downsampling etc

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#1,405 opened on Apr 17, 2024 0 comments 0 reactions 0 assignees View on GitHub

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Assessment

Difficulty: 5/5
Estimated time: Over a week
Newbie friendliness: 35/100

Issue type: Bug
Clarity: Needs clarification
Activity status: Stale
Tech stack: cpp
Domain: computer-vision

Research direction

Read the referenced sections of src/scatter_buildblock/ScatterEstimation.cxx and ScatterSimulation.cxx, then inspect the voxel-sizing function near ScatterSimulation.cxx:920 and its call sites. Determine the intended defaults for downsampled detector resolution in scatter estimation and simulation, and define completion by applying or documenting consistent defaults with validation for both paths.

Written by the indexing model from the issue text.

Description

It looks like our default settings could lead to suboptimal scatter estimates (definitely simulations). I haven't checked the documentation yet.

A potential issue is that, as we use ray-tracing for computing the line integrals (through both emission and attenuation), the image resolution needs to match (downsampled) detector size. This seems currently not implemented by default. Some pointers

scatter estimation

https://github.com/UCL/STIR/blob/8ced2d73933420457e0bc76074964b7d4ff00f0c/src/scatter_buildblock/ScatterEstimation.cxx#L587-L588
https://github.com/UCL/STIR/blob/8ced2d73933420457e0bc76074964b7d4ff00f0c/src/scatter_buildblock/ScatterEstimation.cxx#L558-L563

scatter simulation

https://github.com/UCL/STIR/blob/8ced2d73933420457e0bc76074964b7d4ff00f0c/src/scatter_buildblock/ScatterSimulation.cxx#L320-L326
https://github.com/UCL/STIR/blob/8ced2d73933420457e0bc76074964b7d4ff00f0c/src/scatter_buildblock/ScatterSimulation.cxx#L328-L333

We do have this function which tries to set voxel sizes appropriately, but it seems it isn't called anywhere
https://github.com/UCL/STIR/blob/8ced2d73933420457e0bc76074964b7d4ff00f0c/src/scatter_buildblock/ScatterSimulation.cxx#L920

Dominant language: C++
Stars: 160
Forks: 113
Avg merge: 12d 15h
Merged PRs (30d): 1

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