Fuente: Wipo "precision farming" A process for real-time classification of materials, the process including: conducting laser induced breakdown spectroscopy on the material (LIBS), wherein at least one second laser pulse is directed to the plume so as to selectively energise only a portion of the plume; measuring optical emissions from the energised portion of the plume; and assessing the elemental composition of the material on the basis of the optical emissions from the excited portion of the plume; wherein the energised portion of the plume is substantially smaller than the entire plume so that the measured optical emissions are relatively independent of the size of the entire plume and hence are relatively independent of the optical absorption and vaporisation characteristics of the material, thereby allowing a more accurate assessment of the elemental composition of the material than if the assessment was based on the optical emissions from the entire plume.