阵元固体指向性补偿对超声全聚焦成像的 优化研究*

超声全聚焦成像中,声波的传播受到阵元指向性的影响,位于阵元不同方位的缺陷成像幅度不同。缺陷相对阵列中心偏角越大,回波幅度越低,容易造成漏检。为提高超声全聚焦算法对固体中大偏角缺陷的成像能力,该文引入了矩形阵元固体指向性函数,建立了基于固体指向性补偿的超声全聚焦优化算法,利用指向性系数对不同角度区域的成像进行幅值补偿。实验结果表明,相对于基本超声全聚焦和传统指向性补偿的超声全聚焦算法,该文固体指向性优化算法对大偏角缺陷的成像幅度补偿效果更好,检测灵敏度更高,有效避免了缺陷漏检,扩展了超声全聚焦算法检测范围。

The optimization for ultrasonic total focusing method of solid directivity compensation of array element

The propagation of sound waves is affected by the directivity of the array element, and the total focusing imaging amplitude of defects is different from different angles. The larger the relative angle with the array center, the lower the amplitude of the echo is, which is easy to cause the defects being missed. To improve the inspection effect of TFM to defects with large angles relative to array center, the far field directivity function in solid medium of a single element is applied to the TFM algorithm in this paper, to compensate the amplitude of defects in large angle area. Experimental results show that compared with the basic TFM algorithm and the traditional directional compensation TFM algorithm, the optimized TFM algorithm in this paper based on solid directivity has higher detection sensitivity for defects in large angles, and the effective detection range of TFM is expanded.