diff --git a/aos/vision/blob/transpose.h b/aos/vision/blob/transpose.h
index 632f270..7ac6626 100644
--- a/aos/vision/blob/transpose.h
+++ b/aos/vision/blob/transpose.h
@@ -3,8 +3,7 @@
 
 #include "aos/vision/blob/range_image.h"
 
-namespace aos {
-namespace vision {
+namespace aos::vision {
 
 RangeImage Transpose(const RangeImage &img);
 inline std::vector<RangeImage> Transpose(const std::vector<RangeImage> &imgs) {
@@ -14,7 +13,6 @@
   return out;
 }
 
-}  // namespace vision
-}  // namespace aos
+}  // namespace aos::vision
 
 #endif  // _y2017_VISION_ROT90_H_