On the use of a Transformer Neural Network to deconvolve ultrasonic signals

Pulse-echo ultrasonic techniques play a crucial role in assessing wall thickness deterioration in safety-critical industries. Current approaches face limitations with low signal-to-noise ratios, weak echoes, or vague echo patterns typical of heavily corroded profiles. This study proposes a novel combination of Convolution Neural Networks (CNN) and Transformer Neural Networks (TNN) to improve thickness gauging accuracy for complex geometries and echo patterns. Recognizing the strength of TNN in language processing and speech recognition, the proposed network comprises three modules: 1. pre-processing CNN, 2. a Transformer model and 3. a post-processing CNN. Two datasets, one being simulation-generated, and the other, experimentally gathered from a corroded carbon steel staircase specimen, support the training and testing processes. Results indicate that the proposed model outperforms other AI architectures and traditional methods, providing a 5.45% improvement over CNN architectures from NDE literature, a 1.81% improvement over ResNet-50, and a 17.5% improvement compared to conventional thresholding techniques in accurately detecting depths with a precision under 0.5$\lambda$.