UCL / UCL/STIR

direct parametric reconstruction objective function set_up and time-frame info

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Dominant language
C++
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Forks
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Avg merge
12d 15h
Merged PRs (30d)
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Description

Currently we set-up the single-time-frame objective functions always with the same density
https://github.com/UCL/STIR/blob/fe1af133aee5c44ce9fecd50993612f47d274b44/src/include/stir/recon_buildblock/PoissonLogLikelihoodWithLinearKineticModelAndDynamicProjectionData.txx#L388
This seems dangerous, as it should be a density with the correct time frame info. This seems fixable by using _dyn_image_template to construct an appropriate density. It's a bit wasteful to construct one just for this purpose, but best to be safe.

As the code currently doesn't break, it seems that our set_up functions don't check that proj_data and sensity time frame information is consistent, which seems unsafe. It's possible that they detect that the density time frame information is invalid, and then get on with things nevertheless.

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Research direction

Read the linked PoissonLogLikelihoodWithLinearKineticModelAndDynamicProjectionData.txx around line 388, then trace its set_up functions and uses of _dyn_image_template. Check how the objective-function density receives time-frame information and whether proj_data and sensitivity time frames are validated. Done means the density uses the appropriate frame information and inconsistent inputs are handled safely.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
data
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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