[pdal] Extract terrain from TLS point cloud
Luigi Pirelli
luipir at gmail.com
Mon May 13 00:23:48 PDT 2019
we had similar problems with TLS in urban context regarding first part pf
the cars
you can see our strategy to clean the first PMF effect in slides from
http://slides.com/darango/deck-10-11-12-11-12#/11
to
http://slides.com/darango/deck-10-11-12-11-12#/1
<http://slides.com/darango/deck-10-11-12-11-12#/11>5
the main idea is to do noise cleaning, PMF, filter on normal, filter on
kdistance, PMF again
not clear to me if you can have a good discrimination of the ground part of
the threes using normals due to nature of these surfaces.
cheers
Luigi Pirelli
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On Sat, 11 May 2019 at 10:01, Silvia Franceschi <silvia.franceschi at gmail.com>
wrote:
> Dear all,
> I am trying to extract the ground points from a point cloud of a
> terrestrial laser scanner (TLS) in a forestry environment, but the result
> is not so good as the one I got using data from ALS.
> What I did is:
> 1. denoise the dataset using the filter.outlier and a filter.range for Z
> ranges:
> "type": "filters.outlier",
> "method": "statistical",
> "multiplier": 3,
> "mean_k": 8
> 2. apply a filter.elm and a filter.smrf to the cleaned dataset
> For the SMRF filter I used these parameters:
> "type": "filters.smrf",
> "slope":0.2,
> "window":16,
> "threshold":0.45,
> "scalar":1.2
>
> Unfortunately the resulting ground points contain also the first part of
> of the trunks of the trees, how is it possible?
>
> I am doing some testing changing the values of the SMRF parameters but the
> results are almost the same.
>
> Do some of you have experience with such kind of data? Am I missing some
> operation for filtering? Could you please help me understanding at least
> where to focus the attention to try to obtain something...
>
> Thank you in advance.
>
> Silvia
>
>
> --
> ing. Silvia Franceschi
> Via Roma, 64
> 38030 Castello di Fiemme (TN)
>
> tel: 0039 -3384501332
> _______________________________________________
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> pdal at lists.osgeo.org
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