Abstract: An imaging method using shear waves for observing a viscoelastic medium, comprising: several successive excitation steps j during which elastic shear waves are generated respectively at different excitation loci (Lj) in the viscoelastic medium by an imaging device, the different excitation loci being separated from one another by a maximum distance Dm, an imaging step corresponding to each excitation step j, in which a set j of successive raw images Imj(tk) of the viscoelastic medium at times tk are determined during propagation of the shear wave, the raw images having a resolution R which is larger than the maximum distance Dm, an averaging step in which raw images Imj(tk) corresponding to the same relative time tk are averaged to determine an average image Im?(tk).

Abstract: Method for rheological characterization of a viscoelastic medium, with the following steps: (a) an excitation step during which a vibratory excitation is generated in the viscoelastic medium leading to a deformation of the medium, (b) a deformation measurement step during which the deformation of the medium caused by the excitation is observed, (c) and a characterization step during which at least one non-zero power parameter y is determined such that a rheological parameter of the medium x is equal to x(f)=a+b·fy, where f is the frequency, a is a real number and b a non-zero scale parameter. It is thus possible to obtain mapping of the power parameter y.

Abstract: The invention concerns an image method for observing the propagation of low-frequency shearing pulse wave simultaneously in multiple points of a diffusing viscoelastic medium. The method consists in transmitting at a very high rate ultrasonic compression waves enabling to obtain a succession of images of the medium; then in delayed processing of the resulting images by intercorrelation to determine in each point of each image the movements of the medium while the shearing wave is being propagated.