Registration in CloudCompare using Fine Registration (ICP) tool
Here are videos of the following registration steps.
Open CloudCompare, then drag & drop your scans to load (.las or .ply both work).
We’ve opened 3 scans (Scan 034, 035 & 037) from the same project. You can access all of your opened scans on the left sidebar.
Goal: register 3 scans together for a final aligned point cloud.
Registration is done in pairs. Unselect the box to hide the view of one of the scans so you can work with the other two.
Know which scan will be the (R) reference scan. (Reference scans do not move). Scan 35 will be the (R) scan in our example.
Select scan 34 and click Translate/Rotate.
Unselect the ‘Tz’ box and under Rotation click on ‘Z.’ This prevents rotation & translation along the Z axis so you can easily bring into rough alignment.
Drag the scan to align with the (R) scan. A right click is used to drag the scans, while a left click rotates.
Top View mode found on the left sidebar, can be make alignment easier to see from a top down view.
Once scans are ‘roughly’ aligned then you can use the ICP tool to do a ‘fine’ registration. Rough alignment should look decent to the human eye. That is close enough for the ‘fine’ registration.
Select both Scan 34 & Scan 35 and then click on ICP.
Make sure the reference scan (35 in our example) is correctly marked. If not click ‘swap’ to switch places.
Select how much percentage the ‘aligned’ scan overlaps with the ‘reference’ scan. (It’s better to underestimate than overestimate)
Follow the same steps to register Scan 37 and register it to Scan 35. This can be done by using Translate/Rotate and ICP.
Use the Translate/Rotate tool for a ‘rough’ alignment.
Use ICP tool for ‘fine’ registration.
Final Registration - Three scans registered together
Select each scan and save it individually. Each scan is still a separate file, but registered together.
To save all 3 scans as a single point cloud, select all the scans and save them in a single file.
You may also crop unnecessary regions using the Segment tool.
Other tips for CloudCompare