1. Volume recognition method comprising the steps of: a) capturing three-dimensional image data using a 3D imaging system ( 3 ), wherein said image data represent a plurality of points ( 5 ), each point ( 5 ) having at least a set of coordinates in a three-dimensional space; b) grouping at least some of the points ( 5 ) in a set of clusters ( 6 ); and c) selecting, according to a first set of parameters such as position and size, a cluster ( 6 ) corresponding to an object of interest ( 1 ) located in range of said imaging system ( 3 ); and characterised in that it further comprises the steps of: d) grouping at least some of the points ( 5 ) of the selected cluster ( 6 ) in a set of sub-clusters according to a second set of parameters comprising their positions in the three-dimensional space, wherein each sub-cluster has a centroid ( 11 ) in the three-dimensional space; and e) associating a volume ( 12 ) to each of at least some of said sub-clusters, wherein said volume ( 12 ) is fixed to the centroid ( 11 ) of said sub-cluster.