CameraMapper: make header stripping optional

We have disabled (by default) the header stripping in construction of the
visitInfo, but perhaps someone wants that feature. This change allows
access to that feature through a keyword argument to
CameraMapper._standardizeExposure.

python/lsst/obs/base/cameraMapper.py

@@ -1047,7 +1047,7 @@ def _setFilter(self, mapping, item, dataId):
             self.log.warn("Filter %s not defined.  Set to UNKNOWN." % (filterName))
 
     def _standardizeExposure(self, mapping, item, dataId, filter=True,
-                             trimmed=True, setVisitInfo=True):
+                             trimmed=True, setVisitInfo=True, stripHeader=False):
         """Default standardization function for images.
 
         This sets the Detector from the camera geometry
@@ -1071,6 +1071,8 @@ def _standardizeExposure(self, mapping, item, dataId, filter=True,
             Should detector be marked as trimmed?
         setVisitInfo : `bool`
             Should Exposure have its VisitInfo filled out from the metadata?
+        stripHeader : `bool`, optional
+            Strip header keywords used in determining visitInfo?
 
         Returns
         -------
@@ -1079,7 +1081,7 @@ def _standardizeExposure(self, mapping, item, dataId, filter=True,
         """
         try:
             exposure = exposureFromImage(item, dataId, mapper=self, logger=self.log,
-                                         setVisitInfo=setVisitInfo)
+                                         setVisitInfo=setVisitInfo, stripHeader=stripHeader)
         except Exception as e:
             self.log.error("Could not turn item=%r into an exposure: %s" % (repr(item), e))
             raise
@@ -1308,7 +1310,7 @@ def _initWriteRecipes(self):
             self._writeRecipes[storageType] = validationMenu[storageType](recipes[storageType])
 
 
-def exposureFromImage(image, dataId=None, mapper=None, logger=None, setVisitInfo=True):
+def exposureFromImage(image, dataId=None, mapper=None, logger=None, setVisitInfo=True, stripHeader=False):
     """Generate an Exposure from an image-like object
 
     If the image is a DecoratedImage then also set its WCS and metadata
@@ -1320,6 +1322,17 @@ def exposureFromImage(image, dataId=None, mapper=None, logger=None, setVisitInfo
     image : Image-like object
         Can be one of lsst.afw.image.DecoratedImage, Image, MaskedImage or
         Exposure.
+    dataId : `dict`, optional
+        Data identifier: keyword-value pairs identifying the data. Used for
+        setting the exposureId.
+    mapper : `lsst.obs.base.CameraMapper`, optional
+        Butler's mapper for this particular camera.
+    logger : `lsst.log.Log`, optional
+        Logging object.
+    setVisitInfo : `bool`, optional
+        Set visitInfo in the exposure?
+    stripHeader : `bool`, optional
+        Strip header keywords used in setting visitInfo?
 
     Returns
     -------
@@ -1348,7 +1361,8 @@ def exposureFromImage(image, dataId=None, mapper=None, logger=None, setVisitInfo
                 logger.warn("I can only set the VisitInfo if you provide a mapper")
             else:
                 exposureId = mapper._computeCcdExposureId(dataId)
-                visitInfo = mapper.makeRawVisitInfo(md=metadata, exposureId=exposureId)
+                visitInfo = mapper.makeRawVisitInfo(md=metadata, exposureId=exposureId,
+                                                    stripHeader=stripHeader)
 
                 exposure.getInfo().setVisitInfo(visitInfo)