Rawashdeh Yazan, Kay Steven
IEEE Trans Ultrason Ferroelectr Freq Control. 2020 Aug;67(8):1679-1690. doi: 10.1109/TUFFC.2020.2978807. Epub 2020 Mar 6.
In this article, we construct a new physically motivated model for the grain scattering noise (clutter). We assume the clutter is the output of a random linear time-invariant (LTI) filter, the impulse response of which is considered to be a realization of a Gaussian wide sense stationary (WSS) random process, when the transmitted ultrasonic pulse is at the input. In an ultrasonic non-destructive testing (NDT) session, the clutter noise, which is signal-dependent and caused by the microstructure of the material, presents a substantial challenge in identifying defects in the material under testing. The model is used to aid in the detection of a defect in the material. The model incorporates, explicitly, many important physical characteristics of the generated clutter, such as the average grain size, the random shape, and orientation of the grains, and emphasizes the single scatterer assumption (Rayleigh region). The statistical properties of the model are formulated and derived. A comparison with the usual matched filter to indicate the model advantage is performed. An application to real ultrasonic data is conducted with excellent results. Furthermore, we explored the effect of the choice of the model parameters, and the model shows robustness toward parameter misspecification. We then tested the performance under a deviation from the single scatterer assumption, for a more complex target, using simulated noise and obtained promising results.
在本文中，我们构建了一个基于物理原理的新型颗粒散射噪声（杂波）模型。我们假设杂波是一个随机线性时不变（LTI）滤波器的输出，当发射的超声脉冲作为输入时，该滤波器的脉冲响应被认为是高斯广义平稳（WSS）随机过程的一个实现。在超声无损检测（NDT）过程中，由材料微观结构引起的与信号相关的杂波噪声，给检测被测材料中的缺陷带来了巨大挑战。该模型用于辅助检测材料中的缺陷。该模型明确纳入了所产生杂波的许多重要物理特性，例如平均晶粒尺寸、晶粒的随机形状和取向，并强调单散射体假设（瑞利区域）。对该模型的统计特性进行了公式推导。通过与常用匹配滤波器进行比较来表明该模型的优势。将该模型应用于实际超声数据，取得了优异的结果。此外，我们探讨了模型参数选择的影响，并且该模型对参数指定错误具有鲁棒性。然后，我们针对更复杂的目标，在偏离单散射体假设的情况下，使用模拟噪声测试了性能，并获得了有希望的结果。
