'Find geometry (shapes) from node cloud
I am working on some code that needs to recognize some fairly basic geometry based on a cloud of nodes. I would be interested in detecting:
- plates (simple bounded planes)
- cylinders (two node loops)
- half cylinders (arc+line+arc+line)
- domes (n*loop+top node)
I tried searching for "geometry from node cloud", "get geometry from nodes", but I cant find a nice reference. There is probably a whole field on this, can someone point me the way? i already started coding something, but I feel like re-inventing the wheel...
Solution 1:[1]
To complement Josiah's answer -- since you didn't say whether there is a single such object to be detected in your point cloud -- a good solution can be to use a (generalized) Hough transform.
The idea is that each point will vote for a set of candidates in the parameter space of the shape you are considering. For instance, if you think the current object is a cylinder, you have a 7D parameter space consisting of the cylinder center (3D), direction (2D), height (1D) and radius (1D), and each point in your point cloud will vote for all parameters that agree with the observation of that point. Doing so allows to find the parameters of the actual cylinder by taking the set of parameters who have the highest number of votes. Doing the same thing for planes, spheres etc.., will give you the best matching shape.
A strength of this method is that it allows for multiple objects in the same point cloud.
Sources
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Source: Stack Overflow
| Solution | Source |
|---|---|
| Solution 1 | nbonneel |