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  1. Data Management
  2. DM-12931

Ignore EDGE pixels in coaddition

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    Details

    • Type: Story
    • Status: Done
    • Resolution: Done
    • Fix Version/s: None
    • Component/s: obs_subaru
    • Labels:
    • Team:
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      Description

      In the HSC detectors, charge can pool at the top/bottom of the device. The level (~ 20k) is significantly under the saturation level, so it doesn't get masked and there's no simple way to identify it. Without ignoring EDGE pixels during coaddition (removed in DM-9953), these bad pixels leak into the coadds. We need to revert commit 5faadffd2f408b019280ea1c353f0ec787b092b9.

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          relates to

          Bug - A problem which impairs or prevents the functions of the product. DM-9953 Pixels rejected from coaddition and CCD are not masked on coadds

          • Done

          Story - Created by Jira Software - do not edit or delete. Issue type for a user story. DM-13576 Properly address charge pooling at edges of HSC sensors

          • Won't Fix

            Activity

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            price Paul Price added a comment - 

            price@pap-laptop:~/LSST/obs_subaru (tickets/DM-12931 $%=) $ git sub
            		 
            commit 42b43ff7eab451b469faa33b83eca4ef0d5a95db (HEAD -> tickets/DM-12931, origin/tickets/DM-12931)
            		 
            Author: Paul Price <price@astro.princeton.edu>
            		 
            Date:   Wed Dec 6 15:56:42 2017 -0500
            		 
             
            		 
                Revert "config: allow EDGE pixels to be coadded"
            		 
                
                This reverts commit 5faadffd2f408b019280ea1c353f0ec787b092b9.
            		 
                
                We've identified a reason to ignore EDGE pixels in the coadd:
            		 
                the charge from saturated sources can pool at the top/bottom
            		 
                of the detector. This charge is at a level (~20k) significantly
            		 
                below saturation, so it's difficult to identify cleanly. Tossing
            		 
                all pixels around the edge of the image is the easiest way to
            		 
                ensure these don't leak in.
            		 
             
            		 
             config/assembleCoadd.py         | 2 +-
            		 
             config/safeClipAssembleCoadd.py | 2 +-
            		 
             2 files changed, 2 insertions(+), 2 deletions(-)

            Show
            price Paul Price added a comment - price@pap-laptop:~/LSST/obs_subaru (tickets/DM-12931 $%=) $ git sub commit 42b43ff7eab451b469faa33b83eca4ef0d5a95db (HEAD -> tickets/DM-12931, origin/tickets/DM-12931) Author: Paul Price <price@astro.princeton.edu> Date: Wed Dec 6 15:56:42 2017 -0500   Revert "config: allow EDGE pixels to be coadded" This reverts commit 5faadffd2f408b019280ea1c353f0ec787b092b9. We've identified a reason to ignore EDGE pixels in the coadd: the charge from saturated sources can pool at the top/bottom of the detector. This charge is at a level (~20k) significantly below saturation, so it's difficult to identify cleanly. Tossing all pixels around the edge of the image is the easiest way to ensure these don't leak in.   config/assembleCoadd.py | 2 +- config/safeClipAssembleCoadd.py | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
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            jbosch Jim Bosch added a comment -

            Looks good!

            (I also took the time to re-make that coadd and check both that the feature were gone and that the SENSOR_EDGE masking isn't, so there's no need to do that yourself - I had 99% of the command-line ready to go from testing I did on DM-12933).

            Show
            jbosch Jim Bosch added a comment - Looks good! (I also took the time to re-make that coadd and check both that the feature were gone and that the SENSOR_EDGE masking isn't, so there's no need to do that yourself - I had 99% of the command-line ready to go from testing I did on DM-12933 ).
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            price Paul Price added a comment -

            Thanks Jim.

            Merged to master.

            Show
            price Paul Price added a comment - Thanks Jim. Merged to master.

              People

              Assignee:
              price Paul Price
              Reporter:
              price Paul Price
              Reviewers:
              Jim Bosch
              Watchers:
              Jim Bosch, Paul Price
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                Updated:
                Resolved:

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