1 files changed, 3 insertions, 0 deletions
diff --git a/src/util.h b/src/util.h
index 4666b06..22d5587 100644
--- a/src/util.h
+++ b/src/util.h
@@ -32,4 +32,7 @@ frame_average(struct video_frame *frame);
 void
 print_time(int64_t msec);
 
+int
+sobel(struct video_frame *frame, unsigned char **d);
+
 #endif /* _UTIL_H_ */