In the Terrain from octree dialog windows - "resolution in cm" meaning??
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Hi,
I want to understand
Terrain from octree diaglog windows - resolution in cm.
I read the below explanation on the right side of the window
*The automated method segmenting input base cloud into vegetation and terrain points.
The method of octree is based on recursive dividing base cloud into smaller subset of 8 cubes
until the size of the cube reach the resolution.
For terrain points only the lowest cubes area used.
The method has two pass system.
In the first pass is created rough octree with 10 resolution.
From this cloud is made a fine octree with given resolution in the second pass.
The purpose of this it to remove noise points from result.
When any noise points are preseneted in result.
It can be modified by manual administrator.
*
And also read related part in 3DFroest UserGuide.
*In the dialog window select the base cloud from which you want to extract the terrain, enter a name of the new terrain cloud, a name of the cloud where the rest of data (usually vegetation) will be stored, and set the resolution (edge length of cubes in cm).
*
Let you click below link , you see the octree cubes
https://docs.google.com/document/d/1wmCUIoJ_vaKCYvC23eW63c_MhZk7MA_mp-j64eAZreM/edit?usp=sharing
From there
the edge length of the smallest cube is same as resloution in cm.
Did you get it right?
It would be annoying, but I would appreciate it if you could explain it with a picture.
Thank you in advance.
Hi
the resolution is as you said the length of the smallest cube. The algoritm divide cloud into cubes, selects lowest and those lowest again divide and select the lowest, and againand again... and stops when cube size is equal to given resolution. After selecting the lowest cubes it takes all points that lies inside the lowest cubes with with edge size of resolution.
This is made in first pass on whole cloud, where resolution is coarse (10 * resolution) - that removes majority of tree branches etc. and the second pass use only reduced cloud from the first pass and use fine resolution to get the right terrain points.
Hope it help how it works.
the size of resolution (in cm) have assumption that cloud is in meters. so if your cloud is in mm, you should set resolution 10000.
Jan