Patent ID: 7862508

Claim:
An ultrasound apparatus, comprising: a plurality of transmitters configured to transmit acoustic energy to a tissue of an animal having an anatomy through a coupling medium, such that said acoustic energy becomes scattered by an object in said tissue; a plurality of receivers configured to receive said scattered energy and produce respective analog echo signals; a signal processing component configured to digitize said analog echo signals so as to produce respective digitized signals; a processing module configured so as to: calculate a plurality of first indices, each of said plurality of first indices representing a travel time of said acoustic energy along an assumed path from a transmitter to a voxel in a proposed image plane and from said voxel to a receiver; produce a first set of object data by combining first selected portions of said digitized signals, each of said first selected portions determined based on said plurality of first indices; determine a location of a skin surface of said anatomy, said skin surface representing a scattering interface; calculate a plurality of second indices for said voxels in said proposed image plane, said voxels being located on the opposite side of said skin surface with respect to said plurality of transmitters, each of said plurality of second indices determined by an adjustment to at least one of said plurality of first indices due to refraction of said acoustic energy at said scattering interface, said adjustment determined based on assumed sound speeds in said coupling medium and in said tissue between said scattering interface and said object; and produce a second set of object data by combining second selected portions of said digitized signals, each of said second selected portions determined based on said plurality of second indices; wherein said processing module is further configured to repeat the calculation of said plurality of second indices and producing said second set of object data while varying the assumed speed of sound in said tissue between said scattering interface and said object.