Experimental array data, 1 mm hole at 20 mm depth, Full Matrix Capture from Strategies for data acquisition using ultrasonic phased arrays

Ultrasonic phased arrays have produced major benefits in a range of fields, from medical imaging to non-destructive evaluation. The maximum information, which can be measured by an array, corresponds to the Full Matrix Capture (FMC) data acquisition technique and contains all possible combinations of transmitter–receiver signals. However, this method is not fast enough for some applications and can result in a very large volume of data. In this paper, the problem of optimal array data acquisition strategy is considered, that is, how to make the minimum number of array measurements without loss of information. The main result is that under the single scattering assumption the FMC dataset has a specific sparse structure, and this property can be used to design an optimal data acquisition method. An analytical relationship between the minimum number of array firings, maximum steering angle and signal-to-noise ratio is derived, and validated experimentally. An important conclusion is that the optimal number of emissions decreases when the angular aperture of the array increases. It is also shown that plane wave imaging data are equivalent to the FMC dataset, but requires up to an order of magnitude fewer array firings.

超声相控阵（Ultrasonic phased arrays）已在从医学成像到无损检测的诸多领域中带来了显著效益。相控阵可采集的最大信息量对应于全矩阵捕获（Full Matrix Capture, FMC）数据采集技术，该技术涵盖了所有可能的发射-接收信号组合。然而，该方法在部分应用场景下速度不足，且会生成体量极其庞大的数据。本文探讨了最优阵列数据采集策略问题，即如何在不损失信息的前提下，将阵列测量次数降至最低。核心研究结果表明，在单次散射假设下，全矩阵捕获数据集具有特定的稀疏结构，可依托这一特性设计最优数据采集方法。研究推导了最少阵列激发次数、最大转向角与信噪比之间的解析关系，并通过实验验证了该关系的有效性。一项重要结论为：阵列的角孔径越大，最优激发次数越少。此外，研究还证实平面波成像数据与全矩阵捕获数据集等价，但所需的阵列激发次数最多可减少一个数量级。