Abstract: Method for measuring a physical parameter in soft tissues of a mammal, in which a mechanical shear wave is propagated through the soft tissues and observation of the propagation leads to determine values of a shear wave propagation parameter. The physical parameter is computed on the basis of these values.

Abstract: The invention relates to a method of generating a predetermined objective wave field in a medium using a first network of transducers T1-Tn). The inventive method consists in first using each transducer i of the first network to emit an approximation of the signal ei(t). Subsequently, each transducer of a second network of transducers (T?1-T?m) is used to emit an error signal corresponding to the time reversal of the difference between the signals captured from said first emission and objective signals. Finally, approximation ei(t) is corrected by subtracting the time reversal of the signal captured by each transducer i using the error signal.

Abstract: A Method for measuring heart contractility of a patient, in which a mechanical shear wave is propagated through the heart and observation of the propagation leads to determine a shear wave propagation parameter representative of the elasticity of the heart is disclosed. The value of the propagation parameter at the end of a systole is sampled, which leads to a parameter representative of the end systolic elastance.

Abstract: A non-invasive method of obtaining a target soundwave field in the brain by means of an array of transducers positioned outside the skull, the method comprising a training stage during which, on the basis of a three-dimensional image giving the porosity of the skull at all points, digital simulation is used to determine individual sound signals to be emitted by the transducers in order to obtain the target soundwave field in the brain. After the training stage, the array of transducers is used to locate the position of the array of transducers relative to the skull by echography and to ensure that the array of transducers is accurately positioned.

Abstract: For locating a touch on a tactile surface belonging to an object (7), mechanical waves are made to propagate in the object and these mechanical waves are picked up.

Abstract: The invention relates to a method for measuring a mean visco-elasticity value for a soft material. Said method using a single probe carrying at least one transducer comprises the steps of: a) inducing, in a constraint zone, at least one burst of mechanical vibrations in order to generate internal shear waves in the tissue propagating from said constraint zone into the tissue, b1) measuring, with said transducer, the transient tissue displacements in at least one first measurement zone in the tissue, said first measurement zone being located away from said constraint zone, c) estimating a mean visco-elasticity of the region of the tissue situated between the constraint zone and the first measurement zone from said measured transient tissue displacements of the tissue in the first measurement zone.

Abstract: A method of exploring by wave propagation, in which method an incident wave is emitted a plurality of times towards the same target zone (r0) in a diffusing medium, and then the backscattered signals generated by the waves are averaged.

Abstract: An ultrasound imaging method including an emission step during which an array of transducers is caused to emit at an ultrasound wave focused in a target medium by causing the excitation wave to pass through a reverberant solid object prior to reaching the target medium.

Abstract: According to the invention, a wave, corresponding to a signal s(t) may be temporally inverted by application of a first transformation to lower the central frequency thereof to produce a first set of transformed signals Ki(t) then a second set of transformed signals K?i(t) is produced representing the temporal inversion signal s(?t) and a third transformation is applied to said second set to generate the temporally-inverted signal s(?t)

Abstract: Electrical impedance tomography method comprising: an electrical measurement step during which pre-determined electrical conditions are imposed on the surface of a medium to be imaged, while generating a mechanical disturbance at predefined points of the medium by locally modifying the impedance of the medium and an electrical parameter is measured at several points on the surface of the medium; and a calculation step during which the electrical impedance is determined at several points in the internal volume of the medium, taking into account the measurements carried out during the disturbance, as a function of a law for modification of the electrical impedance by this disturbance.

Abstract: Method for focusing an electromagnetic or acoustic wave on a point near which one or more diffusers are placed, comprising a learning step in which the pulsed responses hij(t) between the focus point and each antenna of the network are determined. Waves corresponding to signals Sji(t)=Si(t)hij(?t), where Si(t) is a function of time and hij(?t) is a temporal inversion of the pulsed response hij(t), can then be transmitted form said antennas of the network.

Abstract: Method for ultrasound imaging comprising at least the following steps: a) a transmission step in which a plurality of ultrasonic waves are transmitted into an imaged region and a set of raw data is acquired by an array of transducers in response to each ultrasonic wave, the ultrasonic waves having different spatial frequency content; b) a coherence enhancing step in which, for each of a plurality of virtual transmit focal zones in the imaged region, at least one set of coherent data is synthesized from the sets of raw data; c) a beamforming step in which, for each of a plurality of locations included in each of the virtual transmit focal zones, an image pixel is computed by beamforming, using the set of coherent data.

Abstract: The inventive imaging method consists in generating a mechanical wave having shearing and compressional components in a viscoelastic medium and in determining the movement parameter of said viscoelastic medium at different points during the propagation of said mechanical wave. Said method comprises a correction stage when the movement parameter is processed for eliminating errors caused by the compressional component of the mechanical wave.

Abstract: The invention concerns a method for optimizing the focusing of waves in a zone of interest of a medium, with the waves being emitted by a network of sources to the medium through an aberration-inducing element that introduces an initially indeterminate phase shift. The method according to the invention proposes to use M?1 successive modifications of the emitted wave, each giving rise to a perturbation. According to the invention, the M perturbations are measured in the zone of interest at each modification of the phase and/or amplitude distributions, and these measurements are used to deduce optimal focusing characteristics to maximize the perturbation induced in the zone of interest.

Abstract: Apparatus and methods for locating an impact point on a surface of an object. The object is provided with an acoustic sensor that senses the impact from the acoustic waves that are generated when the object is subjected to the impact. The location of the impact on the surface of the object is determined by a recognition step that includes a comparison of the sensed signal to one or more predetermined signals. Each predetermined signal represents an active zone on the surface of the object. A predetermined signal corresponds to the sensed signal when the impact causing the sensed signal is generated in the active zone represented by the predetermined signal. The impact is associated with the active zone represented by a predetermined signal when the sensed signal and the predetermined signal sufficiently correspond to each other.

Abstract: Apparatus and methods for locating an impact point on a surface of an object. The object is provided with an acoustic sensor that senses the impact from the acoustic waves that are generated when the object is subjected to the impact. The location of the impact on the surface of the object is determined by a recognition step that includes a comparison of the sensed signal to one or more predetermined signals. Each predetermined signal represents an active zone on the surface of the object. A predetermined signal corresponds to the sensed signal when the impact causing the sensed signal is generated in the active zone represented by the predetermined signal. The impact is associated with the active zone represented by a predetermined signal when the sensed signal and the predetermined signal sufficiently correspond to each other.

Abstract: An ultrasound imaging method including an emission step during which an array of transducers is caused to emit at an ultrasound wave focused in a target medium by causing the excitation wave to pass through a reverberant solid object prior to reaching the target medium.

Abstract: According to the invention, a wave, corresponding to a signal s(t) may be temporally inverted by application of a first transformation to lower the central frequency thereof to produce a first set of transformed signals Ki(t) then a second set of transformed signals K?i(t) is produced representing the temporal inversion signal s(?t) and a third transformation is applied to said second set to generate the temporally-inverted signal s(?t)

Abstract: An imaging method for observing the propagation of a shear wave simultaneously at a multitude of points in a diffusing viscoelastic medium. The shear wave is caused to be generated by firing at least one focused ultrasound compression wave into the viscoelastic medium by means of an array of transducers, and then emitting at a fast rate and using the same array of transducers, unfocused ultrasound compression waves serving to obtain a succession of images of the medium, and processing the images obtained in this way in deferred time in order to determine the movements of the medium during the propagation of the shear wave.

Abstract: The invention concerns a method for focusing acoustic waves useful for obtaining an image of a field to be observed in a dissipative heterogeneous medium (2, 3) around which acoustic transducers (T1–Tn, T?1–T?m) forming an imaging network and a target network. The method consists in following a training step during which pulse responses from the medium are measured between each transducer (Ti) of the imaging network (5) and several transducers (Tj) of the target network (6); deducing therefrom reference signals to be emitted by the transducers of the imaging network to produce a focused acoustic pulse in each transducer of the target network, then cumulatively, in determining reference signals to be emitted to focus an acoustic pulse on predetermined points in the medium. Said reference signals are stored and used subsequently to generate an acoustic image of the medium.