Topics synchronization

[maekjuplease]

Hi,

Thank you for incredible work, I would like to ask how did you synchronize all the topics together since my record rosbag which includes semantic mask, rgb image and IMU are not able to synchronize and displayed "imu message in disorder". Thank you.

[karnikram]

Hi, for our experiments we used the rosbag API to create and add semantic mask messages into the original bagfile (containing RGB and IMU messages) such that they have the same timestamps as the corresponding RGB images.

[maekjuplease]

Thank you for your response. I actually did as the same method that my semantic and RGB image topics have the same timestamps. However, when I launch the VIO, IMU data seem did not fit with RGB and semantic data and return as the following:

Could you please tell me how to solve this issue, thank you.

[karnikram]

This is a warning thrown by VINS-Mono whenever the timestamp of your most recent IMU message is older than the previous one. This can happen because of time synchronization errors between the camera and IMU, or the IMU timestamps are simply incorrect.

However even with perfect synchronization (simulation), the warning still showed up occasionally in our experiments but it didn't affect tracking accuracy as long as the data rate of the IMU messages were fast enough.

[maekjuplease]

Thank you so much for your response.