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UZ-SLAMLab / ORB_SLAM3

ORB-SLAM3: An Accurate Open-Source Library for Visual, Visual-Inertial and Multi-Map SLAM
GNU General Public License v3.0
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Fail to track local map! #929

Open dapao-0808 opened 2 months ago

dapao-0808 commented 2 months ago

Hi! When I use my own device in IMU+Stereo mode, I always encounter the message 'Fail to track local map!' after running for a period of time! Then reset the map, but this phenomenon does not occur in stereo mode. What are the reasons for this phenomenon? f0461041ebb72dc07833866dd9bc644b

boardd commented 3 weeks ago

I am having the same issue! Did you solve it?

dapao-0808 commented 3 weeks ago

My reason is due to excessive calibration errors between the camera and IMU

boardd commented 3 weeks ago

how did you make sure to calibrate it well?

dapao-0808 commented 3 weeks ago

Kalibr tool can be used for calibration to ensure that the reprojection error is within 0.5 pixels, preferably between 0.1 and 0.2.

boardd commented 3 weeks ago

hmm I used kalibr, that doesn't seem to be my issue. Do you know how we should synchronize the camera images and imu timestamps? I am guessing they are not synchronized properly maybe.

dapao-0808 commented 2 weeks ago

There are many factors that affect multi-sensor performance: 1. Whether the clock sources of the sensors are consistent; 2. The frequency of IMU should be at least twice as high as that of the camera, of course, the higher the better; 3. Some scenarios may have a significant impact on IMU, and it may be necessary to continue increasing the frequency of IMU or expanding its random walks and noise, etc. If you don't want to consider so much, you can try using a camera like D435i, which will save a lot of trouble