Modified X waves with improved field properties.
A method to obtain a good compromise between the depth of field and the lateral resolution of "X waves" is proposed. The original X waves are theoretically nondiffracting beams generated by a specially phased infinite transmit aperture. When generated by a finite aperture, X waves are diffracting beams but have a large depth of field, maintaining uniform lateral field profiles. The proposed modification of the wave equation solution for X waves replaces a constant parameter representing the propagation angle of ultrasound with a function of radial distance at the aperture surface, and results in modified X waves that have a larger depth of field than the original X waves. Computer simulations show that a proper choice of the modification function can produce a new beam with improved field properties compared with the original X waves, promising images with higher lateral resolution and increased contrast over a large depth of field in high frame rate medical imaging. Experimental results are presented to verify the simulation results of the proposed method.
Song
T K
TK
Department of Physiology and Biophysics, Mayo Clinic/Foundation, Rochester, MN 55905.
Lu
J
J
Greenleaf
J F
JF
D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D008953:Models, Anatomic; D012542:Scattering, Radiation; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation*