Unusual patterns and colors and bad quality mappings coming from RTabMap

[FeriBolour]

Hey Guys,
So I've been using RTabMap for a while now and I used to get high-quality mappings with it using an Intel D435i for our purposes. Like this one



But about a month ago I started to get very weird results without changing anything in my launch files. I would see very unusual color patterns in my mappings.  For example:

 




And also I would see that straight lines are sometimes warped or curved. For example:





But the main thing that I have been worried about is unusual coloring patterns. At first, I thought it might be the cameras that I have been using. But I have three D435is and they all give me the same kind of results on different computers. Here's a snapshot of the result of a multi-camera configuration that I was working on while the cameras are static and not moving.



You can see how the coloring is completely off.  
So I think one thing that can give more insight into this problem is that when I am using RViz for visualization and I'm looking at the mapping being done online, I can't see any of those coloring patterns and everything seems to be fine. But as soon as I download the map, all those patterns appear on the final point cloud. I don't know if this was helpful but that's the closest I got to finding where the problem is coming from.
Has anyone else recently experienced such a thing as well?
I would appreciate any kind of help and guidance!

Thank You
Farshad Bolouri

[matlabbe]

Hi Farshad,

For the colors, it is because the overlapping clouds don't have the same color. The reason why they don't have the same color is often that auto-exposure or auto-white-balance are enabled on the camera. Are you using rtabmap standalone or on ROS? With ROS, it seems we can fix the exposure: https://github.com/IntelRealSense/realsense-ros/issues/1786

cheers,
Mathieu

[FeriBolour]

Thank You Mathieu for the quick response!
I am indeed using RTabMap with ROS. I will check out the links you sent me and report back my results.