Remove vegetation in agricultural field

[anagellerramser]

Hello,
So, I have two questions:
1st: I have a soybean area and I flew the drone 6 times on different dates (using only the drone's RTK), and I would like to know if the soil z in all these flights is the same (z near zero)
To do this, I thought about removing the vegetation from each of the flights and leaving the ground bare so I could make the flight cloud on date x - the flight cloud on date y (I can't leave the vegetation because I would have the noise from the difference in height of this vegetation).
Does it make sense to check the z value?

That said, 2nd question:

There is no tutorial on the internet on how to remove vegetation from an agricultural area using point clouds.
What I did:
->I imported my point cloud into cloud compare and created a mesh
->I used the Canupo tool to try to classify soil and vegetation, but in the end, there was a lot of vegetation noise.
What can I do?


This is one of the photos of my area.

Thank you in advance

[HeadLess]

Well there are ways to remove vegetation, but are you sure that you only wants to use rtk positions on the drone?

Photogammetry models can be in wrong scale easily. Always use rtk or higher precision ground control points, especially if you want to compare different dates.

1st way to remove vegetation via CSF plugin
https://www.cloudcompare.org/doc/wiki/i ... F_(plugin)

2nd you can use rasterize tool using lowest point in each raster.

3rd hidden point removal
view from bottom and apply hidden point removal.

Ui: you can remove nois by an outlier filter. (Tools - clean -statistical outlier)

[anagellerramser]

Thank you, I will try these. Do you know any tool that uses point color classification? Or if cloud compare allows you to insert a classification equation?

[anagellerramser]

Actually my professor is the one that choose to use only RTK, he is convinced that is enough

[HeadLess]

Thank you, I will try these. Do you know any tool that uses point color classification? Or if cloud compare allows you to insert a classification equation?

You can use coloric segmenter plugin to segment clouds based on color ranges.

https://www.laserscanningforum.com/foru ... hp?t=16106

After that you can assign classification number to the 2 different cloud.

For example for the green stuff set it to vegetation class and the rest to ground.

[anagellerramser]

Thank you so much for your help.
Do you already have some kind of tutorial with more details? I am just beginning with the image processing, so I am very new in this area.
If it works for me, I am willing to record a video to show more people how it's done.

[daniel]

To remove vegetation, have you tried the CSF plugin? (https://www.cloudcompare.org/doc/wiki/i ... F_(plugin))

You can use this 2.13.1 preview version, where it has been improved: https://www.cloudcompare.org/release/Cl ... up_x64.exe (the 2.13.1 version should be released very soon)