Index: trunk/ppStack/src/ppStackReadout.c
===================================================================
--- trunk/ppStack/src/ppStackReadout.c	(revision 20711)
+++ trunk/ppStack/src/ppStackReadout.c	(revision 20883)
@@ -70,4 +70,9 @@
         }
         output = psPixelsConcatenate(output, input);
+    }
+
+    if (!output) {
+        // If there are no pixels to inspect, then just fake it
+        output = psArrayAllocEmpty(0);
     }