curvature analysis

[riveryeti]

This is interesting. I was trying to compute curvature for points using 8 of their neighbors after thinning a .las file that's not dense enough for most ground-finding algorithms to work - it ends up leaving a lot of "spikes" where the trees are. I was trying to figure out why I couldn't partition the convex and concave features with the curvature calculations (if all the "spike" points have the highest positive curvature values it makes them easy to filter out). Then I read in this thread that curvature is unsigned. darn. There goes my chance of using it.

[dylan]

I have a question regarding the curvature analysis. Is it possible to set a normal direction in order to determine a sign for the Gaussian curvature?

A positive Gaussian curvature implies that the surface is synclastic/spherical. In some applications it is useful to know if the Gaussian curvature is negative or positive.

[daniel]

Not sure about this. I'll have to review how the algorithm works...

[Dimitri]

Indeed, that would be super useful to know if the curvature is positive is negative with respect either to the local normal (if known), or to the vertical direction (e.g., a +Z orientation). You could do much more advanced point cloud segmentation with this info.