Index: trunk/psModules/src/imcombine/pmStack.c
===================================================================
--- trunk/psModules/src/imcombine/pmStack.c	(revision 31153)
+++ trunk/psModules/src/imcombine/pmStack.c	(revision 31203)
@@ -37,6 +37,6 @@
 # if (0)
 #define TESTING                         // Enable test output
-#define TEST_X 340                       // x coordinate to examine
-#define TEST_Y 938                       // y coordinate to examine
+#define TEST_X 3145                       // x coordinate to examine
+#define TEST_Y 2334                       // y coordinate to examine
 #define TEST_RADIUS 0.5                 // Radius to examine
 # endif
Index: trunk/psModules/src/imcombine/pmStackReject.c
===================================================================
--- trunk/psModules/src/imcombine/pmStackReject.c	(revision 31153)
+++ trunk/psModules/src/imcombine/pmStackReject.c	(revision 31203)
@@ -125,4 +125,10 @@
     PS_ASSERT_FLOAT_LARGER_THAN_OR_EQUAL(threshold, 0.0, NULL);
     PS_ASSERT_FLOAT_LESS_THAN_OR_EQUAL(threshold, 1.0, NULL);
+
+    if (!subRegions || !subKernels) {
+      psPixels *out = psPixelsCopy(NULL,in);
+      return out;
+    }
+    
     PS_ASSERT_ARRAY_NON_NULL(subRegions, NULL);
     PS_ASSERT_ARRAY_NON_NULL(subKernels, NULL);