Surf Technology As

Other

Eagle Ultrasound As

Angelsen, Bjorn A. J.

Johansen, Tonni F.

Bjorn A J Angelsen

Tonni Franke Johansen

Johannes Kvam

Stian Solberg

Thor Andreas Tangen

Ola Finneng Myhre

Jarle &Oslash;stg&aring;rd

Tonni F Johansen

Estimation and imaging of linear and nonlinear propagation and scattering parameters in a material object where the material parameters for wave propagation and scattering has a nonlinear dependence on the wave field amplitude. The methods transmit at least two pulse complexes composed of co-propagating high frequency (HF) and low frequency (LF) pulses along at least one LF and HF transmit beam axis, where said HF pulse propagates close to the crest or trough of the LF pulse along at least one HF transmit beam, and where one of the amplitude and polarity of the LF pulse varies between at least two transmitted pulse complexes. At least one HF receive beam crosses the HF transmit beam at an angle, to provide at least two HF cross-beam receive signals from at least two transmitted pulse complexes with different LF pulses.

Methods and instrumentation for estimation of wave propagation and scattering parameters

Estimation and imaging of linear and nonlinear propagation and scattering parameters in a material object where the material parameters for wave propagation and scattering has a nonlinear dependence on the wave field amplitude. The methods comprise transmitting at least two pulse complexes composed of co-propagating high frequency (HF) and low frequency (LF) pulses along at least one LF and HF transmit beam axis, where said HF pulse propagates close to the crest or trough of the LF pulse along at least one HF transmit beam, and where one of the amplitude and polarity of the LF pulse varies between at least two transmitted pulse complexes. At least one HF receive beam crosses the HF transmit beam at an angle &#x3e;20 deg to provide at least two HF cross-beam receive signals from at least two transmitted pulse complexes with different LF pulses. The HF cross-beam receive signals are processed to estimate one or both of i) a nonlinear propagation delay (NPD), and ii) a nonlinear pulse form distortion (PFD) of the transmitted HF pulse for said cross-beam observation cell.

Methods and instrumentation for estimation of nonlinear bulk elasticity parameters (NEP) of a material through measuring nonlinear propagation delays (NPDs) at a set of multiple range cells along at least one transmit beam axis, and adapting said NEPs to minimize a functional of the NEPs. The method calculates a distance between a model of the NPDs with the NEPs as input and the measured NPDs, and estimated NEPs are obtained at the minimum of the functional. The NPDs are measured by transmitting at least two pulse complexes comprising a low frequency (LF) and a high frequency (HF) pulse with differences in the LF pulse, along at least one common LF and HF transmit beam axes, and gating out HF receive signals from a multitude of depth ranges along said at least one HF transmit beam axis, and comparing the HF receive signals from two pulse complexes with difference in the LF pulse for each depth range.

Ultrasound estimation of nonlinear bulk elasticity of materials

An acoustic matching layer where the thickness is defined by a single layer of defined mono-disperse particles. The layer comprises a polymer base in which mono-disperse particles are embedded. The mono-disperse particles can be coated with a solid material that participates in the definition of the acoustic impedance of the layer. The polymer base can include smaller solid particles that participates in the definition of the acoustic impedance of the layer. The invention also provides a method of manufacturing.

Ultrasound transducer matching layers and method of manufacturing

The invention presents methods and instrumentation for measurement or imaging of a region of an object with waves of a general nature, for example electromagnetic (EM) and elastic (EL) waves, where the material parameters for wave propagation and scattering in the object depend on the wave field strength. The invention specially addresses suppression of 3order multiple scattering noise, referred to as pulse reverberation noise, and also suppression of linear scattering components to enhanced signal components from nonlinear scattering. The pulse reverberation noise is divided into three classes where the invention specially addresses Class I and Class II 3order multiple scattering that are generated from the same three scatterers, but in opposite sequence.

Nonlinear imaging with dual band pulse complexes

An ultrasound transducer array with at least one composite material layer. The layer having a polymer base in which polymer particles are embedded. The polymer particles are coated with a material that has a thermal conductivity that is higher than the thermal conductivity of the polymer base and the polymer particles.

Ultrasound transducer and method of manufacturing

A design and a manufacturing method of ultrasound transducers based on films of ferro-electric ceramic material is presented, the transducers being particularly useful for operating at frequencies above 10 MHz. The designs also involve acoustic load matching layers that provides particularly wide bandwidth of the transducers, and also multiple electric port transducers using multiple piezoelectric layers, for multi-band operation of the transducers over an even wider band of frequencies that covers &tilde;4 harmonics of a fundamental band. A transceiver drive system for the multi-port transducers that provides simple selection of the frequency bands of transmitted pulses as well as transmission of multi-band pulses, and reception of scattered signals in multiple frequency bands, is presented. The basic designs can be used for elements in a transducer array, that provides all the features of the single element transducer for array steering of the focus and possibly also direction of a pulsed ultrasound beam at high frequencies and multi-band frequencies. The manufacturing technique can involve tape-casting of the ceramic films, deposition of the ceramic films onto a substrate with thick film printing, sol-gel, or other deposition techniques, where manufacturing methods for load matching layers and composite ceramic layers are described.

High frequency and multi frequency band ultrasound transducers based on ceramic films

Ultrasound bulk wave transducers and bulk wave transducer arrays for wide band or multi frequency band operation, in which the bulk wave is radiated from a front surface and the transducer is mounted on a backing material with sufficiently high absorption that reflected waves in the backing material can be neglected. The transducer is formed of layers that include a high impedance section comprised of at least one piezoelectric layer covered with electrodes to form an electric port, and at least one additional elastic layer, with all of the layers of the high impedance section having substantially the same characteristic impedance to yield negligible reflection between the layers. The transducer further includes a load matching section comprised of a set of elastic layers for impedance matching between the high impedance section and the load material and, optionally, impedance matching layers between the high impedance section and the backing material for shaping the transducer frequency response. For multiband operation, the high impedance section includes multiple piezoelectric layers covered with electrodes to form multiple electric ports that can further be combined by electric parallel, anti-parallel, serial, or anti-serial galvanic coupling to form electric ports with selected frequency transfer functions. Each electric port may be separately transceiver-connected to obtain parallel, anti-parallel, serial or anti-serial port coupling for multi-band transmission, and extremely wide-band reception.

Wide or multiple frequency band ultrasound transducer and transducer arrays

An annular ultrasound bulk wave transducer array for electronic depth steering of symmetric focus from a near focus F to a far focus F includes elements that are divided into k groups with different fixed prefocusing. The central group participates in beam forming from F to F , the next outer group in beam forming from F >F to F , and the kth outer group in beam forming from F >F to F . The fixed focus for the kth group is selected at F between F and F . In this manner, beam formation close to F is performed only by the central group. By steering the focus outward from F , the focal diameter increases and, at a depth where the focal diameter exceeds a limit, the next outer group of elements is included in beam formation. This increase in aperture area reduces the focal diameter with subsequent increases in diameter as the focus is further steered toward F . In the same manner, the kth group of elements is included in beam formation for steered foci deeper than F , presenting a growing aperture that enables maintenance of the diameter below limits with a low total number of elements and avoids impractically small widths of the annular elements. The elements may also be subdivided in the angular direction, allowing for phase aberration correction.

Multi pre-focused annular array for high resolution ultrasound imaging

An advantageous combination of preamplifier electronics and circuits for acoustic beam forming with ultrasound transducer arrays permits integration of the electronics and transducer(s) at close distances in a compact arrangement and is operable from an ultrasound imaging or measurement system using only a minimal number of connecting electric wires. To achieve dynamic focusing of the receive beam with a transducer array, an integrated electronic circuit mounted in close proximity to the transducer array provides preamplifiers for the individual elements and delay circuits that are automatically switched in a predetermined time sequence after transmission of an imaging pulse. When a high voltage pulse is transmitted via the cable, a breakthrough circuit connects the cable to the transducer for transmission of the ultrasound pulse, while in receive mode the low level signal on the transducer is amplified and fed as a higher level signal via the same cable to the imaging or measurement instrument.

Ultrasound transceiver system for remote operation through a minimal number of connecting wires

A method of correcting for phasefront aberrations in ultrasound imaging uses highly spaced apart point scatterers artificially placed in the tissue being imaged. The point scatterers reflect the transmitted sound and are individually differentiated to provide singular reference points for correction of signals reflected from the surrounding tissue. The differentiation is performed by comparison of the third or fourth harmonic frequencies of the reflected signals. To ensure the necessary high dispersal of the point scatterers, high amplitude pulses of the transmitted signal destroy point scatterers in selected image regions. In an alternate embodiment, correction is performed by stochastic analysis of signals reflected from the highly dispersed point scatterers. A reference signal is compared to the second harmonic of the reflected signal to reduce noise.

Growing community of inventors

Trondheim, Norway

Bjorn A J Angelsen