Index: trunk/psModules/src/imcombine/pmSubtractionMatch.c
===================================================================
--- trunk/psModules/src/imcombine/pmSubtractionMatch.c	(revision 14605)
+++ trunk/psModules/src/imcombine/pmSubtractionMatch.c	(revision 14606)
@@ -160,5 +160,5 @@
     psRegion *region = NULL;            // Iso-kernel region
     psString regionString = NULL;       // String for region
-    if (isfinite(regionSize) || regionSize != 0.0) {
+    if (isfinite(regionSize) && regionSize != 0.0) {
         xRegions = numCols / regionSize + 1;
         yRegions = numRows / regionSize + 1;