search

ZJU-FAST-Lab / ego-planner

GNU General Public License v3.0
1.31k stars 269 forks source link

Improper camera-IMU time synchronization on Realsense D435i with the driver modifications #25

Closed Pallav1299 closed 2 years ago

Pallav1299 commented 2 years ago

I tried using the modified realsense-ros driver to get input for Stereo-inertial SLAM using VINS-Fusion.

Although the projector dots were almost removed, I witnessed that the changes affected the IMU and camera timestamps.

I compiled the realsense-ros wrapper against the latest librealsense sdk since I was getting runtime errors while building with the suggested librealsense-2.30.0 version.

Open to suggestions.

bigsuperZZZX commented 2 years ago

I think this function will not affect the SLAM performance since we have been using it for a long time. You can adjust the frame rate in launch files so that the camera outputs at the same rate as not using such a feature. One minor difference is the time stamps between depth and gray-scale images since they are outputted alternatively. But this difference should not affect the mapping performance since the time deviation is very small (~16ms at 30fps setting).

bigsuperZZZX commented 2 years ago

It no more questions, I will close this issue.

Pallav1299 commented 2 years ago

@bigsuperZZZX, Sorry for the late reply and thanks for the clarification.

Pallav1299 commented 2 years ago

I noticed a difference in IMU and Camera timestamps. Please check the attached images for the same. I've faced this issue earlier as well. Setting the "initial_reset" flag to "true" acted as a workaround. But not this time.

This issue leads to degradation in SLAM preformance in VINS.

Camera timestamp: camera_timestamp

IMU timestamp: imu_timestamp

Pallav1299 commented 2 years ago

The problem still persists. Please reopen the issue.