Details
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Type:
Story
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Status: Done
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Resolution: Done
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Fix Version/s: None
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Component/s: meas_base
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Labels:
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Story Points:5
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Epic Link:
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Sprint:DRP F16-3, DRP F16-4, DRP F16-5
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Team:Data Release Production
Description
The deblender sometimes gets into trouble with cluster galaxies, and the deblended fluxes aren't accurate. In that case it helps to have measurements on the image without any deblending having been performed. This is a feature used in HSC's mid-2016 production run afterburner, ticket HSC-1400. This feature should be ported for use in LSST.
Attachments
Activity
I've left some comments on the GitHub PR. Feel free to push back if you disagree or create a new issue for anything you think is a good idea but out of scope.
Jim Bosch, I believe I've addressed all your comments. Would you like to have a look at the result?
Paul Price
added a comment - Jim Bosch , I believe I've addressed all your comments. Would you like to have a look at the result? Looks good, merge whenever you're ready.
Thanks Jim.
Merged to master.
Paul Price
added a comment - Thanks Jim.
Merged to master. 
Jim Bosch, I've added a test and the aliases you requested. Would you please give this a proper review? It has passed Jenkins on python 3 and python 2.
price@price-laptop:~/LSST/meas/base (tickets/DM-6785=) $ git subcommit b64fe9448d2f86925f2e341d03af803dfd3c3413Author: Paul Price <price@astro.princeton.edu>Date: Wed Sep 7 15:58:04 2016 -0400provide option to measure on undeblended imageIn some cases, the deblender doesn't do a good job, or we want tocompare what's measured by our code with a different code thatdoesn't do deblending; so we measure on the undeblended image.Refactored the guts of the measurement (mainly the exception handling)in the BaseMeasurementTask to make that easy. SingleFrameMeasurementTaskwill now measure on the undeblended image using a new list of pluginsin SingleFrameMeasurementConfig.undeblended; the results will appearin the catalog with columns named after the measurement algorithms butwith the SingleFrameMeasurementConfig.undeblendedPrefix prepended.python/lsst/meas/base/baseMeasurement.py | 81 +++++++++++++++++++++++---------python/lsst/meas/base/sfm.py | 32 ++++++++++++-2 files changed, 89 insertions(+), 24 deletions(-)commit 0a5ef13cd73fd3519262fd4ffa7e9a87d19408ebAuthor: Paul Price <price@astro.princeton.edu>Date: Thu Sep 8 20:57:05 2016 -0400applyApCorr: allow proxy aperture correctionsAllow the aperture correction model for one measurement to be applied toanother. The aperture correction values are only recorded once.We will use this feature to apply aperture corrections to the undeblendedmeasurements.python/lsst/meas/base/applyApCorr.py | 66 ++++++++++++++++++++++++------------1 file changed, 45 insertions(+), 21 deletions(-)commit 8e729344cfe6a550fae03734ae1ad7d9ed3561bfAuthor: Paul Price <price@astro.princeton.edu>Date: Thu Sep 8 21:07:14 2016 -0400applyApCorr: correct undeblended measurements with proxy modelUse the aperture correction model from the deblended measurements as aproxy to correct the undeblended measurements. The mechanism used is abit more general, doing an aperture correction with a proxy model for anyprefix specified in the new config parameter.python/lsst/meas/base/applyApCorr.py | 11 +++++++++++1 file changed, 11 insertions(+)commit bd34fb788d675125ff28e4babb5f598c90fa4810Author: Paul Price <price@astro.princeton.edu>Date: Fri Sep 23 16:29:40 2016 -0400add test for undeblended measurement and aperture correctiontests/testMeasureSources.py | 119 ++++++++++++++++++++++++++++++++++++++++++++1 file changed, 119 insertions(+)