ENH: Fix Parker weighting to not discard first and last projections - #974
Open
axel-grc wants to merge 1 commit into
Open
ENH: Fix Parker weighting to not discard first and last projections#974axel-grc wants to merge 1 commit into
axel-grc wants to merge 1 commit into
Conversation
SimonRit
requested changes
Jul 23, 2026
SimonRit
left a comment
SimonRit
left a comment
Collaborator
There was a problem hiding this comment.
This is a quite technical problem to address. I'm pretty sure this won't work as there is does not fix the weight by GetAngularGaps in FDKWeightProjectionFilter. A simple test should immediately show a wrong reconstruction. It's a bit worrying that it does not show in the CI.
SimonRit
reviewed
Jul 23, 2026
| // the first and last projections receive non-zero Parker weights. | ||
| if (nProj > 1) | ||
| { | ||
| double angularStep = (lastAngle - m_FirstAngle) / (nProj - 1); |
Collaborator
There was a problem hiding this comment.
I would prefer to add half the first / last angular step on each side rather than an average angular step.
Extend the short scan range by half an angular step on each side so that the first and last projections receive non-zero Parker weights. Previously, these projections were at the ramp-up/ramp-down boundaries and received zero weight, effectively throwing them away. The acquisition actually starts half a step before the first projection and ends half a step after the last, so the weighting should reflect this.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Extend the short scan range by half an angular step on each side so that the first and last projections receive non-zero Parker weights. Previously, these projections were at the ramp-up/ramp-down boundaries and received zero weight, effectively throwing them away. The acquisition actually starts half a step before the first projection and ends half a step after the last, so the weighting should reflect this.
Fix #870