T265 relocalization conflicts with RTAB-Map relocalization

[matlabbe]

There is currently no way to disable relocalization feature from T265. The problem is that when realsense relocalizes, we cannot know how much the old poses have moved (assuming they optimize their map), so the map cannot be optimized on RTAB-Map side.

A workaround is to integrate linear and angular velocities like in this post: IntelRealSense/realsense-ros#779. Modifications would need to be done here. Linear and angular velocites can be fetched like this. EDIT: The problem is that there is always some velocity even when not moving, the resulting pose drifts and is not as accurate than the pose itself (their odometry approach seems to be a frame-to-map approach, not a frame-to-frame approach). An update to realsense API to disable relocalization is the best option.

Note that on ROS, one may use robot_localization package to integrate the twist coming from realsense odometry.

[matlabbe]

Realsense relocalization is now disabled, see the commit above.