Refactor ampOffset correction task

python/lsst/ip/isr/ampOffset.py

@@ -144,10 +144,24 @@ def run(self, exposure):
         ampDims = [amp.getBBox().getDimensions() for amp in amps]
         if not all(dim == ampDims[0] for dim in ampDims):
             raise RuntimeError("All amps should have the same geometry.")
+        else:
+            # The zeroth amp is representative of all amps in the detector.
+            self.ampDims = ampDims[0]
+        # Determine amplifier geometry.
+        # ampWidths = {amp.getBBox().getWidth() for amp in amps}
+        # ampHeights = {amp.getBBox().getHeight() for amp in amps}
+        ampAreas = {amp.getBBox().getArea() for amp in amps}
+        if len(ampAreas) > 1:
+            raise NotImplementedError(
+                "Amp offset correction is not yet implemented for detectors with differing amp sizes."
+            )
 
         # Assuming all the amps have the same geometry.
         self.shortAmpSide = np.min(ampDims[0])
 
+        # TODO: Double check that this is true.
+        assert self.config.ampEdgeWidth < self.shortAmpSide - 2 * self.config.ampEdgeInset
+
         # Fit and subtract background.
         if self.config.doBackground:
             maskedImage = exp.getMaskedImage()
@@ -193,13 +207,6 @@ def run(self, exposure):
                     "config to be 1 or less and rerun."
                 )
 
-            # Determine amplifier geometry.
-            ampAreas = {amp.getBBox().getArea() for amp in amps}
-            if len(ampAreas) > 1:
-                raise NotImplementedError(
-                    "Amp offset correction is not yet implemented for detectors with differing amp sizes."
-                )
-
             # Obtain association and offset matrices.
             A, sides = self.getAmpAssociations(amps)
             B = self.getAmpOffsets(im, amps, A, sides)
@@ -275,9 +282,14 @@ def getAmpAssociations(self, amps):
         ampAssociations = np.zeros((nAmps, nAmps), dtype=int)
         ampSides = np.full_like(ampAssociations, -1)
 
+        # Dictionary mapping side numbers to interface lengths.
+        interfaceLengthLookup = {i: self.ampDims[i % 2] for i in range(4)}
+        # interfaceLengthLookup = {i: 1 for i in range(4)}  # For no weights!
+
         for ampId in ampIds.ravel():
             neighbors, sides = self.getNeighbors(ampIds, ampId)
-            ampAssociations[ampId, neighbors] = -1
+            interfaceWeights = np.array([1 / interfaceLengthLookup[side] for side in sides])
+            ampAssociations[ampId, neighbors] = -1 * interfaceWeights
             ampSides[ampId, neighbors] = sides
             ampAssociations[ampId, ampId] = -ampAssociations[ampId].sum()
 

tests/test_ampOffset.py

@@ -82,6 +82,7 @@ def testAmpOffset(self):
         config = AmpOffsetConfig()
         config.doBackground = False
         config.doDetection = False
+        config.ampEdgeWidth = 12
         task = AmpOffsetTask(config=config)
         pedestals = task.run(exp).pedestals
         self.assertEqual(np.sum(exp.image.array), 0)
@@ -94,6 +95,7 @@ def testAmpOffsetWithBackground(self):
         config = AmpOffsetConfig()
         config.doBackground = True
         config.doDetection = True
+        config.ampEdgeWidth = 12
         task = AmpOffsetTask(config=config)
         pedestals = task.run(exp).pedestals
         nAmps = len(amps)
@@ -117,6 +119,7 @@ def testAmpOffsetWithRampBackground(self):
         config = AmpOffsetConfig()
         config.doBackground = True
         config.doDetection = True
+        config.ampEdgeWidth = 12
         task = AmpOffsetTask(config=config)
         pedestals = task.run(exp).pedestals
         nAmps = len(amps)