diff --git a/include/vision/processor/processor_visual_odometry.h b/include/vision/processor/processor_visual_odometry.h
index 49a5201efbcbde4c0da1401a155685ee334a9d68..ff9bda060ab30b66a0b50828d1876e4e53f93e54 100644
--- a/include/vision/processor/processor_visual_odometry.h
+++ b/include/vision/processor/processor_visual_odometry.h
@@ -209,7 +209,7 @@ class ProcessorVisualOdometry : public ProcessorTracker
 
         void setParams(const ParamsProcessorVisualOdometryPtr _params);
 
-        TrackMatrix getTrackMatrix(){return track_matrix_;}
+        const TrackMatrix& getTrackMatrix() const {return track_matrix_;}
 
 };