Index: /trunk/ippTools/src/regtool.c
===================================================================
--- /trunk/ippTools/src/regtool.c	(revision 10403)
+++ /trunk/ippTools/src/regtool.c	(revision 10404)
@@ -951,4 +951,6 @@
         return false;
     }
+
+    // optional
     psF64 bg = psMetadataLookupF64(&status, config->args, "-bg");
     if (!status) {
@@ -956,8 +958,5 @@
         return false;
     }
-    if (isnan(bg)) {
-        psError(PS_ERR_UNKNOWN, true, "-bg is required");
-        return false;
-    }
+
     psF64 bg_stdev = psMetadataLookupF64(&status, config->args, "-bg_stdev");
     if (!status) {
@@ -965,8 +964,5 @@
         return false;
     }
-    if (isnan(bg_stdev)) {
-        psError(PS_ERR_UNKNOWN, true, "-bg_stdev is required");
-        return false;
-    }
+
     psF64 bg_mean_stdev = psMetadataLookupF64(&status, config->args, "-bg_mean_stdev");
     if (!status) {
@@ -974,8 +970,6 @@
         return false;
     }
-    if (isnan(bg_mean_stdev)) {
-        psError(PS_ERR_UNKNOWN, true, "-bg_mean_stdev is required");
-        return false;
-    }
+
+    // not optional
     psF64 alt = psMetadataLookupF64(&status, config->args, "-alt");
     if (!status) {