diff --git a/y2023/vision/viewer.cc b/y2023/vision/viewer.cc
index 0af7e0e..e03680c 100644
--- a/y2023/vision/viewer.cc
+++ b/y2023/vision/viewer.cc
@@ -1,6 +1,5 @@
 #include "absl/strings/match.h"
-#include "opencv2/calib3d.hpp"
-#include "opencv2/imgproc.hpp"
+#include <opencv2/calib3d.hpp>
 #include <opencv2/highgui/highgui.hpp>
 #include <opencv2/imgproc.hpp>