Re: rtabmap_ros outdoor 3D mapping

Posted by acp on
URL: http://official-rtab-map-forum.206.s1.nabble.com/rtabmap-ros-outdoor-3D-mapping-tp6104p6249.html

Mathieu wrote

The outdoor database is empty, but I did take a look at the indoor one. The artifacts under the floor are caused by reflexions on the surfaces. I think you would see similar behavior with zed depth estimation (in particular on reflective floors). Lights reflecting on the ground can also create points under the ground. Note that reflective surfaces are quite an issue with almost all kind of sensors (stereo, rgb-d, lidar).

So this more an issue of the zed driver, right? there is nothing to do, right? or how can avoid these underground points?

Mathieu wrote

For the double wall effect indoor (as well as the door shifted), it looks caused by some odometry drift. For outdoor, it seems that the depth estimation was not that accurate on that kind of surface or some reasons (are there windows?).

I have used the zed odometer as well as the rtabmap_odometer but the same result with multiple walls. Yea when I tried outdoor, there are windows.

I was suggested by stereolabs:

stereolabs wrote

 The idea will be to use a very sensible edge detection, so most of the color variations in the image are considered as an edge. Then apply a dilate (or erode) (those are OpenCV functions) operation to make the edges bigger in the mask, covering the major part of it. Don't hesitate to make them really bigger as pixels around an edge should be correctly estimated in the depth. The remaining black areas in the image are the ones without any details, the homogeneous ones.

The next step is to take the depth image and modify it so that all the black pixels in the edge-mask are set to NAN in the depth map. Then re-publish the depth map on another topic and you should have a filtered depth ready to be used in RTAB-Map.

I have done what stereolabs suggested using cv_bridge. When I created the depth image with nan values and then I converted cv-image to ros-image with cv_bridge, the nan values were converted to black and I tried with that image but I got the same result.

To be sincere, I do not know what can I do to have a good 3D indoor as well as outdoor maps using rtabmap_ros.


I am looking forward to your replay.