diff --git a/analyzer/pgmtexture.c b/analyzer/pgmtexture.c

index b694219..e33bc5c 100644

--- a/analyzer/pgmtexture.c

+++ b/analyzer/pgmtexture.c

@@ -929,7 +929,7 @@ main (int argc, const char ** argv) {

     FILE * ifP;

     gray ** grays;

-    unsigned int tone[PGM_MAXMAXVAL];

+    unsigned int tone[PGM_MAXMAXVAL+1];

     unsigned int r0, r45, r90;

     unsigned int d;

     unsigned int x, y;