diff --git a/MagickCore/compare.c b/MagickCore/compare.c
index a3914d6..8b2ce81 100644
--- a/MagickCore/compare.c
+++ b/MagickCore/compare.c
@@ -833,7 +833,7 @@
   progress=0;
   for (i=0; i <= MaxPixelChannels; i++)
     distortion[i]=0.0;
-  area=1.0/((MagickRealType) image->columns*image->rows);
+  area=1.0/((MagickRealType) image->columns*image->rows-1);
   image_view=AcquireCacheView(image);
   reconstruct_view=AcquireCacheView(reconstruct_image);
   for (y=0; y < (ssize_t) image->rows; y++)
@@ -1493,7 +1493,7 @@
   image_statistics=GetImageStatistics(image,exception);
   status=MagickTrue;
   distortion=0.0;
-  area=1.0/((MagickRealType) image->columns*image->rows);
+  area=1.0/((MagickRealType) image->columns*image->rows-1);
   image_view=AcquireCacheView(image);
   reconstruct_view=AcquireCacheView(reconstruct_image);
   for (y=0; y < (ssize_t) image->rows; y++)