Fix overscan statistics units in metadata

lsst · Oct 10, 2024 · 57d4a08 · 57d4a08
1 parent f1323ff
commit 57d4a08
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Showing 2 changed files with 9 additions and 4 deletions.
diff --git a/python/lsst/ip/isr/isrTask.py b/python/lsst/ip/isr/isrTask.py
@@ -2274,7 +2274,9 @@ def overscanCorrection(self, ccdExposure, amp):
         ampName = amp.getName()
 
         keyBase = "LSST ISR OVERSCAN"
-        metadata[f"{keyBase} UNITS {amp.getName()}"] = "adu"
+        # The overscan statistics units will always match the units of
+        # the image at the point they are calculated.
+        metadata[f"{keyBase} UNITS"] = metadata["LSST ISR UNITS"]
         # Updated quantities
         if isinstance(overscanResults.overscanMean, float):
             # Serial overscan correction only:

diff --git a/python/lsst/ip/isr/isrTaskLSST.py b/python/lsst/ip/isr/isrTaskLSST.py
@@ -888,9 +888,12 @@ def overscanCorrection(self, mode, detectorConfig, detector, badAmpDict, ccdExpo
 
                     metadata = ccdExposure.metadata
                     keyBase = "LSST ISR OVERSCAN"
-                    # The overscan is always in adu, and we will make this
-                    # explicitly clear
-                    metadata[f"{keyBase} UNITS"] = "adu"
+
+                    # The overscan is always in adu for the serial mode, but it may be electron
+                    # in the parallel mode if doApplyGains==True. If doApplyGains==True, then
+                    # the gains are applied to the untrimmed image, so the overscan statistics
+                    # units here will always match the units of the image at this point.
+                    metadata[f"{keyBase} {mode} UNITS"] = ccdExposure.metadata["LSST ISR UNITS"]
                     metadata[f"{keyBase} {mode} MEAN {ampName}"] = results.overscanMean
                     metadata[f"{keyBase} {mode} MEDIAN {ampName}"] = results.overscanMedian
                     metadata[f"{keyBase} {mode} STDEV {ampName}"] = results.overscanSigma