1. A method for characterizing ultrasound scatterers in a medium, the method comprising: providing ultrasound data representing a region of interest comprising a plurality of scatterers in a medium, the plurality of scatterers including clusters of scatterer sub-units, the scatterers having a physical property value to be estimated and the scatterer sub-units having at least one known physical parameter value; modelling the ultrasound data using an at least second order function of a spatial organization parameter defining the spatial organization of the scatterers; and estimating the physical property value of the scatterers from the modelled ultrasound data and the at least one known physical parameter of the sub-units by a regression of the spatial organization parameter as a function of frequency.