Merge pull request #415 from lsst/tickets/DM-51008

DM-51008: Ensure that fully vignetted pixels and variances are set to 0

Author: erykoff

python/lsst/ip/isr/isrTaskLSST.py

@@ -2239,6 +2239,7 @@ def run(self, ccdExposure, *, dnlLUT=None, bias=None, deferredChargeCalib=None,
 
                 noData = (ccdExposure.mask.array & ccdExposure.mask.getPlaneBitMask("NO_DATA")) > 0
                 ccdExposure.image.array[noData] = 0.0
+                ccdExposure.variance.array[noData] = 0.0
 
             ccdExposure.metadata["LSST ISR FLAT APPLIED"] = True
             ccdExposure.metadata["LSST ISR FLAT SOURCE"] = flat.metadata.get("FLATSRC", "UNKNOWN")

tests/test_isrTaskLSST.py

@@ -1174,6 +1174,9 @@ def test_isrFlatVignette(self):
         noDataExp = (result.exposure.mask.array & result.exposure.mask.getPlaneBitMask("NO_DATA")) > 0
         np.testing.assert_array_equal(noDataExp, noDataFlat)
         np.testing.assert_array_equal(result.exposure.image.array[noDataExp], 0.0)
+        np.testing.assert_array_equal(result.exposure.variance.array[noDataExp], 0.0)
+        self.assertFalse(np.any(~np.isfinite(result.exposure.image.array)))
+        self.assertFalse(np.any(~np.isfinite(result.exposure.variance.array)))
 
     def test_isrFloodedSaturatedE2V(self):
         """Test ISR when the amps are completely saturated.