Abstract: Methods and instruments for suppression of multiple scattering noise and extraction of nonlinear scattering components with measurement or imaging of a region of an object with elastic waves, where elastic wave pulse complexes are transmitted towards said region where said pulse complexes are composed of a high frequency (HF) and a low frequency (LF) pulse with the same or overlapping beam directions and where the HF pulse is so close to the LF pulse that it observes the modification of the object by the LF pulse at least for a part of the image depth. The frequency and/or amplitude and/or phase of said LF pulse relative to said HF pulse varies for transmitted pulse complexes in order to nonlinearly manipulate the object elasticity observed by the HF pulse along at least parts of its propagation, and where received HF signals are picked up by transducers from one or both of scattered and transmitted components of the transmitted HF pulses.

Abstract: Methods and instruments for suppressing multiple scattering noise and extraction of nonlinear scattering components with measurement or imaging of a region of an object with elastic waves, includes transmission of at least two elastic wave pulse complexes towards the region. The pulse complexes include a high frequency (HF) and a low frequency (LF) pulse. The HF pulse is so close to the LF pulse that it observes the modification of the object by the LF pulse at least for a part of the image depth. The frequency and/or amplitude and/or phase of said LF pulse relative to said HF pulse varies for each transmitted pulse complex to nonlinearly manipulate the object elasticity observed by the HF pulse along at least parts of its propagation, and received HF signals are picked up by transducers from at least one of scattered and transmitted components of the transmitted HF pulses. The received HF signals are processed to form measurement or image signals for display.