(no commit message)

[imagemagick] / MagickCore / segment.c

diff --git a/MagickCore/segment.c b/MagickCore/segment.c
index 99a95588040a1dccb5d103d16f2b947163edcd4b..771eb113261f851f50292b006ea17f2d0e68d37d 100644 (file)
--- a/MagickCore/segment.c
+++ b/MagickCore/segment.c
@@ -13,7 +13,7 @@
 %    MagickCore Methods to Segment an Image with Thresholding Fuzzy c-Means   %
 %                                                                             %
 %                              Software Design                                %
-%                                John Cristy                                  %
+%                                   Cristy                                    %
 %                                April 1993                                   %
 %                                                                             %
 %                                                                             %
@@ -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.
   */