The post-processing of ultrasonic array data using the total focusing method
The post-processing of ultrasonic array data using the total focusing method
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DOI：
10.1784/insi.46.11.677.52285
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发表时间：
2004-11-01
期刊：
影响因子：
1.1
通讯作者：
Wilcox, P
中科院分区：
文献类型：
--
作者：
Holmes, C;Drinkwater, BW;Wilcox, P
近年来，超声阵列在无损检测中的使用显着增加。这是由于阵列系统的灵活性，可以通过电子方式配置来产生平面、聚焦、转向和转向聚焦光束。这样，一个阵列传感器就可以完成许多标准单元件传感器的工作。目前，该方法是将独立控制的并行脉冲发生器-接收器通道连接到多个阵列元件。这些通道允许在传输和接收时将定时延迟应用于每个元素。通过这种方式，一组特定的发射-接收延迟被应用于阵列以创建特定的波束轮廓。本文描述了一种替代方法，其中收集、存储和后处理来自每个发射器-接收器对的时域信号的完整原始数据集。理论上，获取该数据所需的时间与使用阵列执行 B 扫描所需的时间大致相同。主要优点是，对完整原始数据集进行后处理可以重新创建任何光束轮廓。此外，这种方法允许执行新颖的检查，这对于单元件传感器来说是不可能的，并且使用传统的相控阵控制器方法也是不切实际的。本文涉及一种这样的后处理算法，即全聚焦法（TFM）。在 TFM 中，创建的图像中光束聚焦在视场内的每个点。这优化了给定阵列的聚焦性能。然后，TFM 的使用在许多测试结构上进行了演示，并被提议作为传统阵列测试技术的更好替代方案。
The use of ultrasonic arrays for NDT has increased significantly in recent years. This is due to the flexibility of array systems which can be electronically configured to produce plane, focused, steered and steer-focused beams. In this way, one array transducer can do the job of many standard single-element transducers. Currently, the approach is to have independently controlled parallel pulser-receiver channels connected to a number of array elements. These channels allow timing delays to be applied to each element on both transmission and reception. In this way a specific set of transmit-receieve delays are applied to an array to create a specific beam profile. This paper describes an alternative approach in which the complete raw data set of time domain signals from every transmitter-receiver pair is collected, stored and post-processed. Theoretically, the time taken to acquire this data is approximately the same as that taken to perform a B-scan with the array. The key advantage is that post-processing of the complete raw data set enables any beam profile to be recreated. Additionally, this approach allows novel inspections to be performed which would be impossible with single-element transducers and impractical using the traditional phased array controller methodology. This paper concerns one such post-processing algorithm, the Total Focusing Method (TFM). In the TFM, an image is created in which the beam has been focused on every point within the field of view. This optimises the focusing performance of a given array. The use of the TFM is then demonstrated on a number of test structures and is proposed as a superior alternative to conventional array test techniques.