Optoelectronic measuring apparatus comprising emitting means suitable, in use, to generate and modulating the optics power of a plurality of trains comprising a plurality of first electromagnetic pulses presenting a first given frequency and a first duration which can be determined substantially at- will; an optical transmission group for the first electromagnetic pulses comprising a waveguide; a detecting group suitable, in use, to sample the time-variation of at least an optical feature of at least an electromagnetic radiation; each radiation having interacted with at least a said train through given Brillouin scattering phenomena at least one portion of said waveguide.