Lost of of old map in orb slam

[vigneshwarvenkat]

Hi Thien,
we were using the orb slam 3 to map out the surrounding, we have encountered this new problem where, once the orb slam lost it's tracking with it's surrounding, it will start a new map with the previous points being deleted but the key frames are still kept intact. Do you know why this happens and how we can prevent it?

[thien94]

In this case, ORB-SLAM loses track because there were not enough features. You can see the line above the first "Fail to track local map", which states fewer than 15 features were being tracked.

You can try tuning the params in the yaml file and maybe that can improve the tracking performance. Regardless, this is one of the common failure cases for monocular VSLAM, besides fast rotation, motion blur, extreme brightness/darkness etc., which can only be fundamentally addressed if you change to stereo / add IMU sensor setup.

You can find various issues in the original ORB-SLAM2/3 repos such as this one raulmur/ORB_SLAM2#919 to learn more.

[vigneshwarvenkat]

Hi, this is a problem we face now, the orb slam view will freeze, previously for about 2 months, this doesnt happen no matter how much blurring or shaking it detect. do you know why it freezes?

[thien94]

Hi @vigneshwarvenkat , sorry for the late reply.

The window "ORB-SLAM3: Current Frame" shows the current tracked image. If this window freezes, it just means that ORB-SLAM3 has lost track and has not been able to recover / create a new map yet. It does not necessarily means the program has stopped working.