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  1. Data Management
  2. DM-38777

LinearizeSpline linearity corrections do not anchor the spline at zero flux



    • Story
    • Status: Done
    • Resolution: Done
    • None
    • ip_isr
    • None
    • 1
    • Data Release Production
    • No


      A discussion on slack noted that images processed with linearity corrections had amp-to-amp offsets that were not seen in uncorrected images.  The most likely cause was the low-flux end of the correction not being anchored at zero, resulting in the sky levels being set from the extrapolation off the lowest flux value listed in the correction table.  As most of the development work with the spline linearizer was done for PTC improvements at high flux, this hasn't been noticed before now.

      The linearity correction calculation should properly fix the lowest-observered flux level to zero, ensure that there's a zero-flux anchor as well, and a similar fix added to the application code to allow existing linearity corrections to be used.


        Issue Links


            czw Christopher Waters created issue -
            czw Christopher Waters made changes -
            Field Original Value New Value
            Status To Do [ 10001 ] In Progress [ 3 ]
            czw Christopher Waters made changes -
            Attachment linearityComparison-20230419b.png [ 67587 ]
            czw Christopher Waters made changes -
            Link This issue relates to DM-38778 [ DM-38778 ]
            czw Christopher Waters made changes -
            Reviewers Dan Taranu [ dtaranu ]
            Status In Progress [ 3 ] In Review [ 10004 ]
            dtaranu Dan Taranu made changes -
            Status In Review [ 10004 ] Reviewed [ 10101 ]
            czw Christopher Waters made changes -
            Resolution Done [ 10000 ]
            Status Reviewed [ 10101 ] Done [ 10002 ]
            yusra Yusra AlSayyad made changes -
            Epic Link DM-32170 [ 779886 ] DM-32177 [ 779901 ]


              czw Christopher Waters
              czw Christopher Waters
              Dan Taranu
              Aaron Roodman, Adam Snyder, Christopher Waters, Dan Taranu, Eli Rykoff
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