Detecting a bump/depression on surface

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mcivie
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Joined: Tue Jan 11, 2022 10:21 am

Detecting a bump/depression on surface

Post by mcivie »

Hello CC community, hello Daniel;

I'm working with scans of pavement surface, my aim is to detect the surface unevenness: I mean the presence of bump and/or depression.
Up to now I used the Roughness tools but, as I learnt, the roughness value is always positive, since CC consider the absolute value to the best fitting plane. Therefore, I can't deduce the correct 'sign' of the distance, distinguishing the fact that it is a bump or a depression.

Now my questions:
1. Is there a way to assess if the point cloud is above or below the best fitting plane?
2. In your opinion, is there a better tool to be used in order to assess if the surface (limited to the Kernel size area) is convex or concave?

I hope I'm clear enough.
Thank for your help
daniel
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Re: Detecting a bump/depression on surface

Post by daniel »

Yes, that's an interesting application.

And there's currently no way to do what you want...

We could add an optional parameter to define the 'vertical' direction. Then, the algorithm would be able to sign the value after making sure the fitted plane is in the right orientation. It would not work in the general case, but for a 2.5D cloud such as a road, it should work I guess.
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daniel
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Re: Detecting a bump/depression on surface

Post by daniel »

Here's what the prototype looks like (with a radius of 4):
Signed_Rouhgness.JPG
Signed_Rouhgness.JPG (326.67 KiB) Viewed 1702 times
Daniel, CloudCompare admin
daniel
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Re: Detecting a bump/depression on surface

Post by daniel »

For information, this is now available in the latest 2.12.beta version!
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daniel
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Re: Detecting a bump/depression on surface

Post by daniel »

Here's another example:
Signed_Rouhgness_2.JPG
Signed_Rouhgness_2.JPG (276.91 KiB) Viewed 1673 times
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mcivie
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Joined: Tue Jan 11, 2022 10:21 am

Re: Detecting a bump/depression on surface

Post by mcivie »

Perfect, thanks.
I'll try immediately.
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