Abstract: Device for the representation, in a frequency-wave number reference frame f-k, of the propagation of an ultrasound wave in a dihedral guide (1), which comprises ultrasound emitters (2) referenced by “Ej” with j an integer varying between 1 and N, N a strictly positive integer and ultrasound receivers (3) referenced by “Ri” with i an integer varying between 1 and M, M a strictly positive integer, the receivers being disposed spatially over a first segment of a straight line according to a regular pitch “A”, which comprises means for processing the signal received by the receivers, originating from the emitters, and in which the processing means comprise means for calculating a modified discrete spatial Fourier transform, for a spatial integration variable “x”, centered in the middle of said first segment and running through the receivers in the direction of increasing x, and for a wave vector k(x) equal to a product k.

Abstract: Device for the representation, in a frequency-wave number reference frame f-k, of the propagation of an ultrasound wave in a dihedral guide (1), which comprises ultrasound emitters (2) referenced by “Ej” with j an integer varying between 1 and N, N a strictly positive integer and ultrasound receivers (3) referenced by “Ri” with i an integer varying between 1 and M, M a strictly positive integer, the receivers being disposed spatially over a first segment of a straight line according to a regular pitch “A”, which comprises means for processing the signal received by the receivers, originating from the emitters, and in which the processing means comprise means for calculating a modified discrete spatial Fourier transform, for a spatial integration variable “x”, centered in the middle of said first segment and running through the receivers in the direction of increasing x, and for a wave vector k(x) equal to a product k.

Abstract: A probe including NE ultrasonic emitters and NR ultrasonic receivers is applied on the medium to be characterized. Each emitter is activated successively and each time signals are detected on the set of receivers during a time window. Each of the NE×NR signals detected is converted by temporal Fourier transformation to a sum of vibrational components each having its temporal frequency. For each frequency, a matrix NE×NR of complex amplitudes of vibrational components having this frequency is extracted. These matrices are decomposed into singular values, the smallest are eliminated, and the singular vectors associated with the singular values retained, a base of the space of the reception signals is formed, for each frequency. The contribution of each plane wave, characterized by its velocity, in this base is calculated. This contribution is represented in the form of a grey level in a frequency-propagation velocity reference system.

Abstract: A probe including NE ultrasonic emitters and NR ultrasonic receivers is applied on the medium to be characterized. Each emitter is activated successively and each time signals are detected on the set of receivers during a time window. Each of the NE×NR signals detected is converted by temporal Fourier transformation to a sum of vibrational components each having its temporal frequency. For each frequency, a matrix NE×NR of complex amplitudes of vibrational components having this frequency is extracted. These matrices are decomposed into singular values, the smallest are eliminated, and the singular vectors associated with the singular values retained, a base of the space of the reception signals is formed, for each frequency. The contribution of each plane wave, characterized by its velocity, in this base is calculated. This contribution is represented in the form of a grey level in a frequency-propagation velocity reference system.

Abstract: A method for displaying scanned ultrasound images of tissue employs an apparatus including an ultrasound probe mounted to a mechanical head. A three-dimensional positioning system mounts the head for positioning the probe in proximate orthogonal relation to the tissue. A computer controls the three-dimensional positioning system thereby moving the probe during a scan. The probe transmits high frequency ultrasound waves whose nominal frequency is included within the range from 30 to 100 MHz and with a large pass band, adapted to frequencies reflected by the tissue. The beams of ultrasound transmission are focused in a given zone of the tissue over a vertical penetration distance of between 20 and 30 mm. Reflected signals are acquired and processed for display.

Abstract: A method for displaying scanned ultrasound images of tissue employs an apparatus including an ultrasound probe mounted to a mechanical head. A three-dimensional positioning system mounts the head for positioning the probe in proximate orthogonal relation to the tissue. A computer controls the three-dimensional positioning system thereby moving the probe during a scan. The probe transmits high frequency ultrasound waves whose nominal frequency is included within the range from 30 to 100 MHz and with a large pass band, adapted to frequencies reflected by the tissue. The beams of ultrasound transmission are focused in a given zone of the tissue over a vertical penetration distance of between 20 and 30 mm. Reflected signals are acquired and processed for display.

Abstract: The scanning system of the invention includes a structure driven in rotation around a first axis, a structuremounted rotating on the structure around an axis parallel to the first axis, a structure for supporting an echographic probe mounted rotating on the structure around a third axis parallel to the axis, a coupling element between the structure and the structure and a coupling element between the support structure and the structure. This system being able to move the probe along a variable band arciform trajectory.

Abstract: The scanning system of the invention includes a structure driven in rotation around a first axis, a structuremounted rotating on the structure around an axis parallel to the first axis, a structure for supporting an echographic probe mounted rotating on the structure around a third axis parallel to the axis, a coupling element between the structure and the structure and a coupling element between the support structure and the structure. This system being able to move the probe along a variable band arciform trajectory.

Abstract: Catheter for echographic imaging within a cavity, comprising a proximal end situated to the outside of the patient, a distal end situated close to the tissues which are to be investigated, and a body connecting these two ends, the distal end comprising a guide wire and a capsule which is transparent to ultrasound and in which are accommodated a fixed piezoelectric transducer and a mirror for deflecting the ultrasonic wave and driven by means of rotation accommodated in the said capsule, this catheter being characterized in that the said mirror (30) is placed directly, without torque transmission shaft, on the surface of the rotor (34) of a microactuator constituting the said means of rotation.

Abstract: A method for the in vivo evaluation and characterization of the mechanical or architectural properties of bones relies on the propagation of an ultrasound wave through the bone and subsequently studying the interaction of this wave with the bone. The bone is scanned using an ultrasound beam obtained from focused transducers. Then, the signals transmitted through the bone and/or reflected by the faces of the bone and/or scattered by the internal structures of the bone are collected. The signals obtained are stored in memory. The signals thus stored are processed for measuring: the propagation velocity of the ultrasound beam in the bone; the thickness of the bone; the transmission attenuation coefficient of the ultrasound beam; and the reflection parameters for estimating the backscatter and attenuation coefficients.