Is there a topic or service to know when visual odometry estimation is lost in RTAB-MAP?

edit

Hello,

I am using rtabmap to estimate odometry from visual slam. When odometry is lost, the rtabmapviz screen becomes red. I am looking for one way to know when I lose odometry in my code e.g. a topic to subscribe or something like that.

Thanks for your help

(Edit)

I am using ROS kinetic and the following launch files:

roslaunch freenect_launch freenect.launch depth_registration:=true

roslaunch rtabmap_ros rtabmap.launch localization:=true rtabmapviz:=false rviz:=true