Missaligned clusters/scans

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[email protected]
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Missaligned clusters/scans

Post by [email protected] »

Hello everyone!

Recently I have encountered a problem with a point cloud that seems very
difficult to be registered correctly ( the critical issue is at some sets of scans
with a small ovelap ). Tried to merge the clusters with recap 2022 and scene
2021.4.0 but had no luck. The rotation of the scans is wrong at the side view
all the times even thought i tried to enchance the scans with additional points
or after registering with the inclinometer off. Tried to place them correctly in
the visual registration of scene but I could only rotate it in the top view.
( If i remember correctly in old versions of scene after turning off the
inclinometer the visual registration allowed the scans/clusters to be rotated
at all axes ).In recap, it can be merged correctly till some point but
there is always a set of scans that doesn't cooperate at all. Tried to reimport
the scans, import some scans from scene and register together but still nothing.

Thanks in advance.
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Tanguy Nédélec
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Re: Missaligned clusters/scans

Post by Tanguy Nédélec »

Hello,

About your levelling problem: you should be able to right-click a scan/cluster, go to properties->transformation tab, and manually change the rotation values here. My version of Scene (2019.2) allows me to rotate a scan/cluster around all axes if inclinometers are turned off, that's not the case with 2021.4.0?
Alternatively, you could probably define 3-4 well distributed points on the floor, export them, edit the Z in the csv so that it's the same, re-import the csv, and register using the target method, with inclinometer disabled. Of course, you would then assume that the ground is level...

About your registration mismatch, you would have to identify where exactly is the problem. To do so, create a thin clipping box, and visually inspect the registration in correspondence view (do an horizontal one and a few vertical ones). If you notice a particular spot where scans are not tightly fit together, try to sub-cluster that area, and see it gives better results. Cleaning up the scans beforehand might help (mirrors, glass, vegetation, etc.).

If it's a lack of overlap problem, your only solution might be to go back and do a few additional scans.

PS: how big is your project? Maybe you could post an overall screenshot?
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