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Subject: Re: 3D surface recon from point cloud
Date: Wed, 26 Mar 2008 13:38:02 +0000 (UTC)
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Can you send me a reference to this paper?
I have a bunch of 2-D data points of a hallway in my 
building (laser scanner mounted on robot with SLAM).   And 
I want to plot it as a wireframe model of the hall way.

Is this the type of algoirthm you would have to use?   or 
is there an easy way to do this? 

"Ashish A" <aashi6uf@mathworks.com> wrote in message 
<fnqvbu$mvm$1@fred.mathworks.com>...
> Hello
> 
> I have been working on a project to do a surface 
> reconstruction from a point cloud.  I am writing my code 
> in Matlab and using the algorithm described by Hoppe et 
> al.  
> 
> Step 1: finding k neighbors and using principal 
component 
> analysis to find a center and a normal for the plane.
> 
> Step 2: Orienting the normals: this is where I am having 
> some difficulty.  I am generating a Euclidean minimum 
> spanning tree in 3d based on the algorithm described at 
> wikipedia.  Basically, first calculating Delaunay 
> triangulation to calculate edges (distance between 
> points).  Then starting from the point with highest z, I 
> am using prim&#8217;s algorithm to generate the EMST.  Once, I 
> have the EMST, I am orienting the normal&#8217;s to point 
> outward.  
> 
> Step 3:  Surface Contouring:  I am planning to use the 
> marching cube algorithm but haven&#8217;t written the code yet.
> 
> The step 2 seems to work fine for small set of data 
points 
> (sample data points up to 100-200) but when I try it 
with 
> the actual data set (~20000 points), it seems to take it 
> forever.  I have let it run for over 8 hours without 
> getting any results.  Even if it is working, I don&#8217;t 
think 
> it is acceptable.  I am sure the surface contouring part 
> will be computationally long as well.  So, my question 
is 
> that are there any tricks that other have been using for 
> orienting the normals of the tangent planes.  Or are 
there 
> any already existing functions for this?
> 
> My other question is about surface contouring.  I feel 
> confident that if I can get the normal orientation 
right, 
> I should be able to do this by a brute force marching 
cube 
> algorithm.  But, I would like to use the iso-surface 
> function of the matlab instead of writing the whole new 
> code to generate facets information.  Any helpful 
pointers 
> there?
> 
> Many thanks,
> Ashish
>