Bin difference image

lsst · Oct 7, 2021 · 8c2b2de · 8c2b2de
1 parent 88fff79
commit 8c2b2de
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Showing 3 changed files with 15 additions and 7 deletions.
diff --git a/pipelines/measurePhotonTransferCurve.yaml b/pipelines/measurePhotonTransferCurve.yaml
@@ -40,3 +40,4 @@ tasks:
       ptcFitType: FULLCOVARIANCE
 contracts:
   - ptcSolve.maximumRangeCovariancesAstier == ptcExtract.maximumRangeCovariancesAstier
+  - ptcSolve.binSize == ptcExtract.binSize
diff --git a/python/lsst/cp/pipe/ptc/cpExtractPtcTask.py b/python/lsst/cp/pipe/ptc/cpExtractPtcTask.py
@@ -429,10 +429,6 @@ def measureMeanVarCov(self, exposure1, exposure2, region=None, covAstierRealSpac
             im1Area = exposure1.maskedImage
             im2Area = exposure2.maskedImage
 
-        if self.config.binSize > 1:
-            im1Area = afwMath.binImage(im1Area, self.config.binSize)
-            im2Area = afwMath.binImage(im2Area, self.config.binSize)
-
         im1MaskVal = exposure1.getMask().getPlaneBitMask(self.config.maskNameList)
         im1StatsCtrl = afwMath.StatisticsControl(self.config.nSigmaClipPtc,
                                                  self.config.nIterSigmaClipPtc,
@@ -464,6 +460,9 @@ def measureMeanVarCov(self, exposure1, exposure2, region=None, covAstierRealSpac
         diffIm -= temp
         diffIm /= mu
 
+        if self.config.binSize > 1:
+            diffIm = afwMath.binImage(diffIm, self.config.binSize)
+
         diffImMaskVal = diffIm.getMask().getPlaneBitMask(self.config.maskNameList)
         diffImStatsCtrl = afwMath.StatisticsControl(self.config.nSigmaClipPtc,
                                                     self.config.nIterSigmaClipPtc,
@@ -489,7 +488,7 @@ def measureMeanVarCov(self, exposure1, exposure2, region=None, covAstierRealSpac
         # calculations below.
         w = unmasked*wDiff
 
-        if np.sum(w) < self.config.minNumberGoodPixelsForCovariance:
+        if np.sum(w) < self.config.minNumberGoodPixelsForCovariance/(self.config.binSize**2):
             self.log.warn(f"Number of good points for covariance calculation ({np.sum(w)}) is less "
                           f"(than threshold {self.config.minNumberGoodPixelsForCovariance})")
             return np.nan, np.nan, None

diff --git a/python/lsst/cp/pipe/ptc/cpSolvePtcTask.py b/python/lsst/cp/pipe/ptc/cpSolvePtcTask.py
@@ -154,6 +154,11 @@ class PhotonTransferCurveSolveConfig(pipeBase.PipelineTaskConfig,
         doc="Use bootstrap for the PTC fit parameters and errors?.",
         default=False,
     )
+    binSize = pexConfig.Field(
+        dtype=int,
+        doc="Bin the image by this factor in both dimensions.",
+        default=1,
+    )
 
 
 class PhotonTransferCurveSolveTask(pipeBase.PipelineTask,
@@ -595,8 +600,11 @@ def errFunc(p, x, y):
                 parsIniPtc = [-1e-9, 1.0, 10.]  # a00, gain, noisei^2
                 # lowers and uppers obtained from BOT data studies by
                 # C. Lage (UC Davis, 11/2020).
-                bounds = self._boundsForAstier(parsIniPtc, lowers=[-1e-4, 0.5, -2000],
-                                               uppers=[1e-4, 2.5, 2000])
+                if self.config.binSize > 1:
+                    bounds = self._boundsForAstier(parsIniPtc)
+                else:
+                    bounds = self._boundsForAstier(parsIniPtc, lowers=[-1e-4, 0.5, -2000],
+                                                   uppers=[1e-4, 2.5, 2000])
             if ptcFitType == 'POLYNOMIAL':
                 ptcFunc = funcPolynomial
                 parsIniPtc = self._initialParsForPolynomial(self.config.polynomialFitDegree + 1)