From: cristy <urban-warrior@git.imagemagick.org>
Date: Wed, 15 Jan 2014 00:54:40 +0000 (+0000)
Subject: (no commit message)
X-Git-Tag: 7.0.1-0~2866
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=375bd90594d2371ee0f41f092886220c875d4ff7;p=imagemagick

---

diff --git a/MagickCore/segment.c b/MagickCore/segment.c
index 5f3d912e8..771eb1132 100644
--- a/MagickCore/segment.c
+++ b/MagickCore/segment.c
@@ -1186,15 +1186,18 @@ MagickExport MagickBooleanType GetImageDynamicThreshold(const Image *image,
         cluster=cluster->next;
       }
     }
-  threshold=(background->red.center+object->red.center)/2.0;
-  pixel->red=(double) ScaleCharToQuantum((unsigned char)
-    (threshold+0.5));
-  threshold=(background->green.center+object->green.center)/2.0;
-  pixel->green=(double) ScaleCharToQuantum((unsigned char)
-    (threshold+0.5));
-  threshold=(background->blue.center+object->blue.center)/2.0;
-  pixel->blue=(double) ScaleCharToQuantum((unsigned char)
-    (threshold+0.5));
+  if (background != (Cluster *) NULL)
+    {
+      threshold=(background->red.center+object->red.center)/2.0;
+      pixel->red=(double) ScaleCharToQuantum((unsigned char)
+        (threshold+0.5));
+      threshold=(background->green.center+object->green.center)/2.0;
+      pixel->green=(double) ScaleCharToQuantum((unsigned char)
+        (threshold+0.5));
+      threshold=(background->blue.center+object->blue.center)/2.0;
+      pixel->blue=(double) ScaleCharToQuantum((unsigned char)
+        (threshold+0.5));
+    }
   /*
     Relinquish resources.
   */