Measurement and Imaging of Scatterers with Memory of Scatterer Parameters Using at Least Two-Frequency Elastic Wave Pulse Complexes

An instrument for measurement or imaging of elastic wave nonlinear scatterers with a memory of scattering parameters in a region of a scattering object, the instrument comprising:

• a) at least one controller configured to:
• i) select LF pulses having characteristics to change the scattering parameters of the nonlinear scatterers with a memory that lasts for at least a time interval after the incident LF pulse has passed the nonlinear scatterer;
• and
• ii) determine transmit time relation between the LF and HF pulses so that at least in the measurement or imaging range the incident HF pulse propagates spatially behind the incident LF pulse and close enough to the incident LF pulse that the HF pulse hits the nonlinear scatterers while the effect of the incident LF pulse on its scatterer parameters is observed by the HF pulse;
• b) a transmitter configured to:
• transmit at least two elastic wave pulse complexes towards the region, each of the at least two elastic wave pulse complexes comprising a high frequency (HF) pulse in an HF band and a selected low frequency (LF) pulse in an LF band, wherein at least the LF pulse varies for at least two transmitted pulse complexes, the LF pulse of a pulse complex can be zero, the LF pulse for at least one pulse complex is nonzero, and in the pulse complexes comprising an HF pulse and a nonzero LF pulse, the transmit time relations have the selected transmit time;
• and
• c) a receiver configured to pick received HF signals from at least one of scattered and transmitted HF components from the at least two transmitted pulse complexes;
• wherein the at least one controller is further configured to combine the received HF signals from the at least two pulse complexes with different LF pulses to form nonlinear measurement or imaging HF signals that represent the local resonant scatterers, with suppression of received HF signals from other scatterers.