Surf Technology As

Johannes Kvam

Bjorn A J Angelsen

Stian Solberg

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.

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Oslo, Norway

Johannes Kvam