ACOUSTIC IMAGING BY NONLINEAR LOW FREQUENCY MANIPULATION OF HIGH FREQUENCY SCATTERING AND PROPAGATION PROPERTIES

摘要

New methods of acoustic imaging are presented that provide images with reduced reverberation noise and images of nonlinear scattering and propagation parameters of the object, and estimation methods of corrections for wave front aberrations produced by spatial variations in the acoustic propagation velocity. The methods find use in a variety of applications such as acoustic imaging of geological structures, SONAR imaging of sub-sea objects, and medical ultrasound imaging. The methods are based on processing of the received signal from transmitted dual frequency band acoustic pulse complexes with overlapping high and low frequency pulses. The high frequency pulse is used for the image reconstruction and the low frequency pulse is used to manipulate the nonlinear scattering and/or propagation properties of the high frequency pulse.