Add subtask to find and mask satellite trails

This commit adds a new subtask in findSatellites.py and a call to
that task in CompareWarpAssembleCoaddTask, where it is used to
detect satellite trails or other linear features in difference
images. This will only run if the config option
doFilterMorphological is set to True.

doc/lsst.pipe.tasks/tasks/lsst.pipe.tasks.findSatellites.FindSatellitesTask.rst

@@ -0,0 +1,26 @@
+.. lsst-task-topic:: lsst.pipe.tasks.findSatellites.FindSatellitesTask
+
+##################
+FindSatellitesTask
+##################
+
+.. _lsst.pipe.tasks.findSatellites.FindSatellitesTask
+
+Python API summary
+==================
+
+.. lsst-task-api-summary:: lsst.pipe.tasks.findSatellites.FindSatellitesTask
+
+.. _findSatellites.FindSatellitesTask-subtasks:
+
+Retargetable subtasks
+=====================
+
+.. lsst-task-config-subtasks:: lsst.pipe.tasks.findSatellites.FindSatellitesTask
+
+.. _lsst.pipe.tasks.findSatellites.FindSatellitesTask-configs:
+
+Configuration fields
+====================
+
+.. lsst-task-config-fields:: lsst.pipe.tasks.findSatellites.FindSatellitesTask

python/lsst/pipe/tasks/assembleCoadd.py

@@ -42,6 +42,7 @@
 from .scaleZeroPoint import ScaleZeroPointTask
 from .coaddHelpers import groupPatchExposures, getGroupDataRef
 from .scaleVariance import ScaleVarianceTask
+from .findSatellites import FindSatellitesTask
 from lsst.meas.algorithms import SourceDetectionTask
 from lsst.daf.butler import DeferredDatasetHandle
 
@@ -1742,6 +1743,11 @@ class CompareWarpAssembleCoaddConfig(AssembleCoaddConfig,
         target=SourceDetectionTask,
         doc="Detect sources on static sky model. Only used if doPreserveContainedBySource is True"
     )
+    findSatellites = pexConfig.ConfigurableField(
+        target=FindSatellitesTask,
+        doc="Detect satellite trails on difference between each psfMatched warp and static sky model. "
+            "Only used if doFilterMorphological is True."
+    )
     maxNumEpochs = pexConfig.Field(
         doc="Charactistic maximum local number of epochs/visits in which an artifact candidate can appear  "
             "and still be masked.  The effective maxNumEpochs is a broken linear function of local "
@@ -1810,6 +1816,12 @@ class CompareWarpAssembleCoaddConfig(AssembleCoaddConfig,
         dtype=float,
         default=0.05
     )
+    doFilterMorphological = pexConfig.Field(
+        doc="Filter artifact candidates based on morphological criteria, i.g. those that appear to "
+            "be satellite trails.",
+        dtype=bool,
+        default=False
+    )
 
     def setDefaults(self):
         AssembleCoaddConfig.setDefaults(self)
@@ -1991,6 +2003,8 @@ def __init__(self, *args, **kwargs):
             self.makeSubtask("detectTemplate", schema=afwTable.SourceTable.makeMinimalSchema())
         if self.config.doScaleWarpVariance:
             self.makeSubtask("scaleWarpVariance")
+        if self.config.doFilterMorphological:
+            self.makeSubtask("findSatellites")
 
     @utils.inheritDoc(AssembleCoaddTask)
     def makeSupplementaryDataGen3(self, butlerQC, inputRefs, outputRefs):
@@ -2172,6 +2186,7 @@ def findArtifacts(self, templateCoadd, tempExpRefList, imageScalerList):
         spanSetArtifactList = []
         spanSetNoDataMaskList = []
         spanSetEdgeList = []
+        spanSetBadMorphoList = []
         badPixelMask = self.getBadPixelMask()
 
         # mask of the warp diffs should = that of only the warp
@@ -2201,6 +2216,12 @@ def findArtifacts(self, templateCoadd, tempExpRefList, imageScalerList):
                     spans.setImage(slateIm, 1, doClip=True)
                 epochCountImage += slateIm
 
+                if self.config.doFilterMorphological:
+                    fitResult = self.findSatellites.run(warpDiffExp, slateIm)
+                    satMask = afwImage.Mask(coaddBBox)
+                    satMask.array[fitResult.mask] = 1
+                    spanSetSatellite = afwGeom.SpanSet.fromMask(satMask)
+
                 # PSF-Matched warps have less available area (~the matching kernel) because the calexps
                 # undergo a second convolution. Pixels with data in the direct warp
                 # but not in the PSF-matched warp will not have their artifacts detected.
@@ -2217,12 +2238,15 @@ def findArtifacts(self, templateCoadd, tempExpRefList, imageScalerList):
                 nansMask = afwImage.MaskX(coaddBBox, 1)
                 spanSetList = []
                 spanSetEdgeMask = []
+                spanSetSatellite = afwGeom.SpanSet([])
 
             spanSetNoDataMask = afwGeom.SpanSet.fromMask(nansMask).split()
 
             spanSetNoDataMaskList.append(spanSetNoDataMask)
             spanSetArtifactList.append(spanSetList)
             spanSetEdgeList.append(spanSetEdgeMask)
+            if self.config.doFilterMorphological:
+                spanSetBadMorphoList.append(spanSetSatellite)
 
         if lsstDebug.Info(__name__).saveCountIm:
             path = self._dataRef2DebugPath("epochCountIm", tempExpRefList[0], coaddLevel=True)
@@ -2233,6 +2257,8 @@ def findArtifacts(self, templateCoadd, tempExpRefList, imageScalerList):
                 filteredSpanSetList = self.filterArtifacts(spanSetList, epochCountImage, nImage,
                                                            templateFootprints)
                 spanSetArtifactList[i] = filteredSpanSetList
+            if self.config.doFilterMorphological and (spanSetBadMorphoList[i].getArea() != 0):
+                spanSetArtifactList[i].append(spanSetBadMorphoList[i])
 
         altMasks = []
         for artifacts, noData, edge in zip(spanSetArtifactList, spanSetNoDataMaskList, spanSetEdgeList):