Is RGB and depth data synced in the driver before publishing to ROS2 ?

yenle3997

I have an OakDLite (with IMU), and I want to input its RGBD data, A1M8 LiDAR, and encoders into RTABMAP for 3D outdoor mapping. In the RTABMAP guide, it mentioned an example of Intel Realsense already synced its depth and RGB data in the driver, so the approx_sync parameter in RTABMAP can be turned off for the depth camera. I wonder if this is the same for the depthv3 driver ? I am using Jazzy.

Oskar-Luxonis

Hey yenle3997 - the DepthAI v3 ROS driver can sync the OAK RGB and stereo depth streams when rgb.i_synced: true and stereo.i_synced: true are enabled. Internally it uses a DepthAI Sync node and republishes the grouped image messages with matching timestamps.

That said, for RTAB-Map I would keep approx_sync:=true in your case. The DepthAI ROS driver’s own RTAB-Map launch file does this by default, even with RGB/depth sync enabled. This is especially important because your setup also includes an external A1M8 LiDAR and encoders, which are not automatically synchronized by the OAK driver.

So: for only the OAK RGB+depth pair, exact sync may work if you verify matching timestamps on /oak/rgb/image_raw and /oak/stereo/image_raw. For the full outdoor mapping setup with LiDAR and encoders, use approximate sync.

Thanks,
Oskar