Hi,
You can use parameter "Grid/MaxObstacleHeight" (in meters). This assumes that the camera is fixed on the robot and the robot is moving on the ground (filtering is done in "frame_id" frame).
For UAV or hand-held mapping, the robot/camera must first be aligned to ground (you can use "Odom/AlignWithGround" for that if rgbd_odometry is used), then set also "Grid/MapFrameProjection" to true so that filtering is done in /map frame. This approach cannot handle 3D terrain or multi-floor.
For car navigation, I would try first the standard navigation stack of ROS using 2D occupancy grid map and possibly an
ackermann planner. Another
post here.
cheers,
Mathieu