Tree point Cloud Segmentation

[Tasiyiwa Priscilla Muumbe]

Hi,

I am relatively new to LAStools and I wanted to find out if it is possible to segment trees from a Terrestrial LiDAR point clouds.

[Paul Manley]

Sure. And welcome. 

Is your data classified already? 

Paul

On Tue, Feb 16, 2021, 3:33 AM Tasiyiwa Priscilla Muumbe <tasima...@gmail.com> wrote:

Hi,

I am relatively new to LAStools and I wanted to find out if it is possible to segment trees from a Terrestrial LiDAR point clouds.

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[Tasiyiwa Priscilla Muumbe]

yes, data is classified.

May you shed more light on the actual segmentation process.

Thanks.

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[Paul Manley]

If you just want a LAS file with vegetation only, you can use 

las2las -i input.las -keep_class x -o output.las

Where 'x' is the classification number of the vegetation you want to isolate.

Does that help, or are you looking for something else?

Paul

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[Tasiyiwa Priscilla Muumbe]

I want to do individual tree segmentation.

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[Paul Manley]

Hi Tasiyiwa,

Did you get further help on this yet? If not, can you send a screenshot or explain how dense the vegetation is that you're interested in?

Regards,

Paul Manley

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[Daniel Andrade]

I believe that she needs the individual delimitation of the trees. I saw something about it with mean shit segmentation. 

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[Karol K.]

Hi,

LAStools will not help you much with ITD (Individual Tree Detection) as it does not have tools for either detection or segmentation of tree crowns. What you should look into is a separate algorithm, that either takes classified LiDAR point cloud data, or perhaps already pre-processed CHM (like the pit-free algorithm described here: https://rapidlasso.com/2014/11/04/rasterizing-perfect-canopy-height-models-from-lidar/)

Here are some tools available that will help you:

https://github.com/manaakiwhenua/pycrown

https://github.com/redfoxgis/tree_segmentation

https://github.com/mparkan/Digital-Forestry-Toolbox/blob/master/scripts/tree%20metrics/treeWatershed.m

Hope it helps

K

[Tasiyiwa Priscilla Muumbe]

yes, I want individual delimitation of trees. I got help on this matter.

Thank you

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[Daniel Andrade]

How did you manage to solve this problem? Did you use Mean-shift?

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[erik....@gmail.com]

Hej,

I agree with Karol. I've been working on individual tree detection / segmentation using LAStools to transfer my point-clouds to clean data, which I can then use to analyze further with R.

Take a look at the R-package lidR which can be used to do the further steps:

        introduction: https://github.com/Jean-Romain/lidR

        https://jean-romain.github.io/lidRbook/index.html 

        detailed description of its ITD/S capabilities: https://jean-romain.github.io/lidRbook/itd-its.html

Maybe this helps!

Regards,

    Erik

[Daniel Andrade]

In R, mean shift segmentation is implemented for ITD and ITS. 

Thank you very much, Erik. We hope to solve this problem in LiDAR data. 

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[Paul Manley]

Yeah, this is why I was asking how dense the area is with trees. If they're pretty sparse, then you can easily output las/shapefiles showing just where that class of vegetation is. If it's a forest, that's another issue.

Paul

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[Julia Tatum]

I’m not sure about terrestrial lidar (never worked with it), but the lidR package in R does a really good job of individual tree segmentation for aerial lidar.  The package is pretty easy to work with and has really good documentation.

 

Julia

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[Tanvir Ahmed Shovon]

Please read this article. Here you will find a package uses Terrestrial lidar data.

https://www.sciencedirect.com/science/article/pii/S0034425720304314

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Regards,

Shovon

Tanvir Ahmed Shovon

Postdoctoral Fellow

Department of Renewable Resources 

Faculty of Agricultural, Life and Environmental Sciences

University of Alberta

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