聚焦换能器自由场互易校准的冲击响应积分法衍射系数计算

Computation of diffraction loss coefficient of free field reciprocitycalibration for focusing transducers by use of impulseresponse integral method

在聚焦换能器的会聚球面波自由场互易校准法中,衍射损失修正系数是获得互易常数的一个关键参数.本文利用冲击响应函数积分法系统地计算了超声治疗头、机械扫描B超探头以及多普勒诊断探头的衍射损失系数,得出了一些典型参数下的计算曲线,可供不同类型的聚焦换能器会聚球面波互易校准时引用.与传统的瑞利积分法分析比较显示,本文中所采用的冲击响应函数积分法显著地提高了运算速度,同时基本保持了与瑞利积分算法计算结果的一致性.

During free field reciprocity calibration for a convergent spherical acoustic wave of a focusing transducer, the diffraction loss correction coefficient is a key parameter of obtaining the reciprocity coefficient. In this paper, we use the so-called impulse response integral method instead of the Rayleigh integral method to calculate the diffraction loss coefficients of various therapy transducers such as the mechanical-scanning B-Mode transducers and the Doppler transducers. Some numerical graphs with typical parameters are given. Compared to the Rayleigh integral method, the impulse response integral method greatly reduces the computational time while at the same time maintaining the accuracy of the computation results to certain extent.