[PIPE2D-785] Add option to use tweaked detectorMap to define fiberProfiles Created: 17/Mar/21  Updated: 27/Mar/21  Resolved: 27/Mar/21

Status: Done
Project: DRP 2-D Pipeline
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Story Priority: Normal
Reporter: rhl Assignee: price
Resolution: Done Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Attachments: PNG File quiver-46188-fiberTrace.png    
Sprint: 2DDRP-2021 A3
Reviewers: hassan

 Description   

Looking at the discrepancies between the detectorMap and the fiberProfile centres shows that the Chebyshev fit to the x-centres is pretty good, but not perfect.  Using the detectorMap (probably with an affine distortion) would be better.  The figure shows every fifth fibre, and clearly some of the fits are a bit off (much worse in the dense-pack region).  Using the black spots will help here, of course, but a global distortion would probably be better.

 Comments   
Comment by price [ 17/Mar/21 ]

I think the default profiles.centroidRadius=5 is too large to work well in the dense fiber region. The other features look smooth, and could be fixed using a higher order polynomial (currently profiles.centerFit.order=9).

Comment by rhl [ 17/Mar/21 ]

Maybe we'd get away with that, but ignoring the detectorMap in favour of a per-fibre fit is the wrong thing to do.

Comment by price [ 26/Mar/21 ]

Ready for review.

Comment by hassan [ 26/Mar/21 ]

This looks fine. Minor comments in the pull request. One question: is the adjusted detectorMap persisted? I could not see that. May be useful for debugging to have that option.

Comment by price [ 26/Mar/21 ]

The detectorMap isn't adjusted: the trace positions are.

Comment by rhl [ 26/Mar/21 ]

I think Hassan's request is reasonable, but possibly a different ticket.  Currently only arcs can be used to adjust the positions of the traces in the DetectorMap, and this is a problem for e.g. the SuNSS blue arm where we have decent quartzes but only very sparse arcs (especially before we found out about "dome arcs").  Obviously you can only update the wavelengths directly by using the arcs, but in reality I suspect that you can do a pretty good job just off the traces (or will, once we understand the space of distortions in the cameras)

Comment by price [ 27/Mar/21 ]

Created PIPE2D-796: Allow adjustment of detectorMap in reduceExposure.

Comment by price [ 27/Mar/21 ]

Merged.

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