The waveform digitizer (produced by Optech, Canada) is an instrument that allows to digitize the signals recorded by the ALTM receiver. By reconstructing the waveform of the recorded impulses and using special software and algorithms, it is possible to get further information regarding the nature of the surveyed objects, therefore improving the quality of the product (for instance, the classification of the laser points). In particular, complex vertical structures can be analyzed, typically vegetation forms for forestry studies.