Index: trunk/psLib/src/imageops/psImageBackground.c
===================================================================
--- trunk/psLib/src/imageops/psImageBackground.c	(revision 15920)
+++ trunk/psLib/src/imageops/psImageBackground.c	(revision 15938)
@@ -66,4 +66,10 @@
         n++;
     }
+    if (n < 0.01*Nsubset) {
+	psLogMsg ("psLib", PS_LOG_INFO, "too few data points");
+	psFree (values);
+	return false;
+    }
+
     values->n = n;