  We use the mathematical toolbox of the inverse scattering transform to study
quantitatively the number of solitons in far from equilibrium one-dimensional
systems described by the defocusing nonlinear Schr{\"o}dinger equation. We
present a simple method to identify the discrete eigenvalues in the Lax
spectrum and provide a extensive benchmark of its efficiency. Our method can be
applied in principle to all physical systems described by the defocusing
nonlinear Schr{\"o}dinger equation and allows to identify the solitons velocity
distribution in numerical simulations and possibly experiments.
