CO-KR-3 Shape optimization of acoustic lens beamformers

抄録

Shape optimization of an acoustic lens system is presented by using the hybrid approach that employs geometric acoustics as well as wave acoustics.Geometric acoustics is used to obtain the rays of acoustic wave from the wave source to the exit plane that is placed right after the final lens.Snell's law is used to calculate paths of rays and transmitted pressures through lenses are calculated by multiplying the incident wave with transmission coefficients.Diffraction of the wave is not considered in the geometric acoustics.Two methods are used to obtain the acoustic pressure distribution at the pressure field.The first and second method uses the Kirchhoff integral theorem and the Boundary Element Method(BEM) to calculate the acoustic pressure distribution from the exit plane to the image plane,respectively; the pressure magnitude at the focal point as well as those at side lobes can be calculated.A lens design problem is formulated as the optimization problem that maximizes the pressure magnitude at the focal point.The effectiveness of the proposed approach is verified by showing a design example for a spherical lens system.