No time sync between imu messages and tracking camera image messages in ROS



  • I recorded a rosbag from M500 and looked closely at the timestamps (header.stamp in ros messages) of my imu messages [IMU0) and image messages (tracking camera). I see that they are not synced. I am attaching the files in drive link for your perusal. The timestamp I am providing in the files is directly obtained from ros messages. There is no post processing.
    https://drive.google.com/drive/folders/18PzGYlnwzXftc_U19rA7rDzj4ZeKoSEm?usp=sharing

    Please clarify if the ros messages should be time synced for IMU0 and tracking camera as expected for a good VIO stack or I am missing something.
    Another thing to note is I am seeing perfect time sync in the stereo images.


  • Dev Team

    The tracking camera and imu will not be time synced. The tracking camera samples at 30 hz whereas the imu samples at around 1khz. This allows for the vio algorithm to continue to estimate position between tracking camera frames and provide closer to real-time odometry.



  • ok. But in the ros-topics I am getting messages at ~220 hz only. Do I need to configure anything to record the ros imu messages at 1 Khz.

    Another clarification I will need is the mv-vislam library uses IMU from the modal pipes at 1 kHz with 30 Hz images from the camera server.


Log in to reply