毫米级弹性散射子半径的超声定量检测

Ultrasonic quantitative detection of millimeter-scale elastic scatterer radius

毫米或微米尺度散射体的超声定量是工业和医学诊疗领域的重要课题。笔者以毫米级球形弹性散射子为目标,采用数值方法研究其背散射波形态函数f_(∞)(π)和目标强度T_(s),分析了球体材料、半径a等参数的影响。由于散射波干涉会造成T_(s)与a存在多值问题,笔者提出利用差频叠加方法对散射信号强度进行处理以减弱或消除干涉,实现散射子半径定量。结果表明,在一定带宽范围内,对散射波信号进行差频叠加可有效减弱干涉。试验结果也证实采用目标强度可在一定精度范围内,对毫米级球形散射子半径进行定量。

Quantitative detection of scatters in millimeter or micron scale is an important topic in the field of industrial manufacturing,medical diagnosis and treatment.In this study,millimeter scale elastic spheres were regarded as the detection targets,the shape function f_(∞)(π)and the target strength T_(s)are numerically calculated,and the influence of material and radius are also analyzed.In order to solve the multi-value problem between T_(s)and the radius a,a solution is proposed by using the difference frequency superposition of scattering signal intensity to attenuate or even eliminate acoustic interference and realize the quantification of scattering radius.The results show that the superposition method can effectively attenuate the acoustic interference in a certain bandwidth,and the experimental results also confirm that the radius of millimeter spherical scatters can be quantified by measuring the strength within a certain precision.