1 - On my theses which is about extraction of poles at mobile laser scanner point cloud, First point cloud should be separated to ground points and non ground points which pole points are inside of non-ground point section. for doing that, 2D Dimension of point cloud at XY plane is gridded(m*m). then at each square, minimum height is calculated and those points elevation of them are less than total minimum elevation and a threshold height, are consider ground points. with this simple method, ground points are denoted.
2- for extraction of traffic signs at lidar data, simply with intensity(almost maximum intensity) and a shape filter, they are could be extraction.
Hi Dinesh, I use the Point Data Abstraction Library (http://pdal.io) for tasks like ground extraction. Check filters.pmf (https://pdal.io/stages/filters.pmf.html) and filters.smrf (https://pdal.io/stages/filters.smrf.html), there are links to the research papers describing the methods also. They’re pretty robust and can be used for mobile LIDAR applications.
I see you like MATLAB (based on tags) - you can expose MATLAB functions to PDAL as well (https://pdal.io/stages/filters.matlab.html#filters-matlab), although I prefer the Python API (PDAL can be called as a Python library as well as calling Python functions inside PDAL pipelines).
The neat thing about either approach is that you can use any object-finding methods developed in MATLAB or Python directly in the processing pipeline.
…and you can take advantage of point cloud library tools as well (https://pdal.io/stages/filters.pclblock.html#filters-pclblock).
I like PDAL because it’s easy to create recyclable processing pipelines pretty easily, especially messing around in automating processes, treating the JSON pipelines as templates which can have parameters passed in; or mixing JSON configurations and command line over-rides. And I don’t have to write my own file readers and writers (yet) :D
Extracting street signs seems like a cool project - keep posting updates; and good luck!
Adam Steer It's my pleasure to see this one of the powerful answers I've seen, thank you for the suggestion of PDAL.
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