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

摘要

Measurement or imaging of elastic wave nonlinear scatterers with a memory of scattering parameters comprises selecting LF pulses having characteristics to change the scattering parameters of nonlinear scatterers. A transmit time relation is selected so that the incident HF pulse propagates sufficiently close to the LF pulse that the effect of the incident LF pulse on its scatterer parameters is observed by the HF pulse. At least two elastic wave pulse complexes comprising a high frequency (HF) pulse and a selected low frequency (LF) pulse are transmitted towards the region. Received HF signals are combined to form nonlinear HF signals representing the scatterers with memory, with suppression of received HF signals from other scatterers. At least one of the received HF signals may be corrected by time delay correction and/or speckle correction with a speckle correction filter, determined by movement of the scattering object. Systems are also disclosed.

主权项

1. A method for measurement or imaging of elastic wave nonlinear scatterers with a memory of scattering parameters in a region of a scattering object, comprising:
a) selecting LF pulses having characteristics to change the scattering parameters of at least certain 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; b) selecting a transmit time relation between the LF pulses and HF pulses so that at least in the measurement or imaging depth range the incident HF pulse propagates spatially behind the incident LF pulse of the same pulse complex, but sufficiently close to the 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; c) transmitting at least two elastic wave pulse complexes towards the region, the 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 non-zero LF pulse, the transmit time have the selected transmit time relation; d) picking up received HF signals from at least one of scattered and transmitted HF components from the at least two transmitted pulse complexes; and e) combining the received HF signals from the at least two pulse complexes to form nonlinear measurement HF signals representing the nonlinear scatterers with memory of scattering parameters, with suppression of received HF signals from other scatterers.