Index: /trunk/ippTools/src/regtool.c
===================================================================
--- /trunk/ippTools/src/regtool.c	(revision 10402)
+++ /trunk/ippTools/src/regtool.c	(revision 10403)
@@ -784,4 +784,6 @@
         return false;
     }
+
+    // optional
     psF64 bg = psMetadataLookupF64(&status, config->args, "-bg");
     if (!status) {
@@ -789,8 +791,5 @@
         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) {
@@ -798,8 +797,5 @@
         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) {
@@ -807,8 +803,6 @@
         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) {