[QUESTION] IMU topics and Image rgb raw topics are not synchronized

[robotsorcerer]

Hi there,

I am trying to use your rosbags from uHumans in a separate work.

I collected all the rgb image topics, lidars and imus in a message filters callback and I am subscribing to these using ApproximateTimeSynchronizer. With TimeSynchronizer the messages never really arrive for onward processing by the imu preintegrator. So we are stuck with the approximate synchronizer anyway.

(Pardon me, I am not all too familiar with GTSAM, so I am doing the preintegration on my own).

I found that the timestamps on the IMU publishers and Image publishers are so different that relying on the timestamp for data association among multiple sensor modalities is fruitless.

Is there a way you avoided this in your IMU preintegration with GTSAM?

[robotsorcerer]

Okay, so I think the IMU data were captured at a rate almost 1ms smaller than the images. Explains my problem. Best I can do is throttle the images on a different topic and call the synchronizer in my callback for throttled image and IMU topics. Thanks!