Index: trunk/ippconfig/recipes/ppSub.config
===================================================================
--- trunk/ippconfig/recipes/ppSub.config	(revision 24657)
+++ trunk/ippconfig/recipes/ppSub.config	(revision 24673)
@@ -44,4 +44,9 @@
 INTERPOLATION	STR	LANCZOS3	# Interpolation mode for bad pixels
 
+VARIANCE.RESCALE           BOOL FALSE	# empirically rescale the variance?
+VARIANCE.RESCALE.NSAMPLE   S32  100000	# number of pixels to select from image for measurement
+VARIANCE.RESCALE.MIN.VALID F32  0.66	# do not rescale the variance if the measured sigma less than this value (where 1.0 is expected)
+VARIANCE.RESCALE.MAX.VALID F32  1.50	# do not rescale the variance if the measured sigma more than this value (where 1.0 is expected)
+
 DUAL		BOOL	FALSE		# Dual convolution?
 INVERSE		BOOL	FALSE		# Generate inverse subtraction?