Function and scripts I haven't found anywhere and I had to write them myself...
This repository contains:
ncart2sph.m - function that computes N-dimensional transformation from Cartesian to Spherical coordinates (simple implementation)
ncart2sph_fast.m - same as above, but faster.
wccn.m - performs within-class covariance normalization.
desa1.m - Instantaneous frequency using Discrete Energy Separation Algorithm.