Introduction
Purpose
Uniformed structures are a difficult environment for scanning devices. The SLAM can get lost due to the structure uniformity no matter how careful the scanning style is.
This article includes some tips and tricks that tested to be helpful in such environments.
1 Use cardboard boxes to create unique objects
The idea is to create some unique objects in the uniform environment, and collapsible cardboard boxes are a good material for creating cubic or triangular objects. They can be stuck to the wall or ceiling, or can be placed on the ground. The boxes used in this example are 50x40x30 cm.
Note: the unique objects that aid SLAM could also be barrels or traffic cones.
2 Place the unique structures every 10-15 meters
Place objects every 10-15m, so one or more unique structures can always be detected while mapping. In the quality map, the objects should show up like this:
3 Take multiple mapping runs without noticeable SLAM issue and use control points
Map slowly and steadily. Observe the live map and see if there are noticeable SLAM drift / lost behaviors. If SLAM is lost even after adding structures, then try placing more unique structures and mapping more steadily. Take at least two successful mapping runs without noticeable SLAM errors, and use control points.
Note: the extra objects used to aid the SLAM in the tunnel will be present in the final data Point cloud. One needs to decide beforehand where to put those objects to not block important tunnel features.
FAQ
What is the purpose of this article?
The article provides tips and tricks for using scanning devices in uniformed structures, where SLAM can struggle due to the lack of unique features.
How can I create unique objects in a uniform environment?
You can use collapsible cardboard boxes to create cubic or triangular objects, which can be placed on walls, ceilings, or the ground.
How far apart should unique structures be placed?
Unique structures should be placed every 10-15 meters to ensure they can be detected while mapping.
Is it necessary to take multiple mapping runs?
Yes, it is recommended to take at least two successful mapping runs without noticeable SLAM errors and to use control points.
Will the extra objects used to aid SLAM appear in the final data point cloud?
Yes, the extra objects will be present in the final data point cloud, so it's important to place them thoughtfully to avoid blocking important features.