97
20. Save both point clouds in case you run into issues in the next step and need to start
over.
MERGING POINT CLOUDS
21. Load the .ply files you want to merge into CloudCompare.
22. Apply a unique color to each point cloud. To do this, select the point cloud and press
Alt+C. Select a unique color. Do this for each point cloud.
23. Select the two point clouds on the DB Tree box. Go to Tools>Registration>Align. This
will require that you select 4 equivalent points in each of the point clouds.
24. Alternatively, you can use the Edit>Translate/Rotate to visually and manually get the
point clouds close. If you level each point cloud, you can select to rotate about z and
translate in x and y using the check boxes in the Translate/Rotate option box that
pops up.
25. Next, use the Tools>Registration>Fine Registration (ICP) Process to do fine
registration: These steps require some practice and are the most time-consuming
part of this process. Please see the next section on ICP Matching Instructions using
CloudCompare.
26. After you have fine registered both point clouds, merge them into one. Edit>Merge.
27. If you still want to merge more files into this point cloud, use this result to merge with
the next one and repeat it.
Please note that manipulating very large point clouds in a graphical way may be a very
performance-intensive task. You could experience some lags on CloudCompare.
ICP MATCHING IN CLOUDCOMPARE
This section shows how to use the Iterative Closest Point (ICP) matching function in
CloudCompare to merge point clouds. As you might know, the ICP matching can generate
problematic results if not used correctly.
We will use a dataset from a Carnegie Mellon University Campus building as an example. A
ground map was built by walking around the building. An aerial map was made by flying over the
building.
There are three key points for aligning the two maps. Please keep these points in mind when you
read.
1. Downsize point clouds before ICP matching
2. Trim aerial map to better overlap with the ground map before ICP matching
3. Repeat ICP matching multiple times to make sure of convergence
To Next Page
Loading...
