Access Eigenvalues / Eigenvector

[RauchLukas]

I am trying to compute speciffic Point Cloud Point Features, like e.g. Omnivariance.

like in Weinmann 2014, these features can derived the 3 Eigenvalues of every Point in the Point Cloud.

I was wandering, if there is a easy way to access / compute the Eigenvalues directly API build in functions?
with this question I imply, that open3D calculates the eigenvalues at some point anyway. not least because the eigenvalues are also used in e.g. a simple PCA for plane fitting.