C1-a5 - Real-Time Adaptive Ultrasonic Plane Wave Imaging towards Online Automated Curved Structure Inspection
- Event
- 2025 ICU PADERBORN - 9th International Congress on Ultrasonics
2025-09-21 - 2025-09-25
Paderborn - Band
- Lectures
- Chapter
- C1-a - Acoustic Imaging and Beamforming Applications
- Author(s)
- Z. Chang, S. Wu, K. Yang, H. Jin - Zhejiang University, Hangzhou (China)
- Pages
- 186 - 189
- DOI
- 10.5162/Ultrasonic2025/C1-a5
- ISBN
- 978-3-910600-08-9
- Price
- free
Abstract
Phased array ultrasonic imaging is widely utilized in industrial non-destructive testing and evaluation (NDT&E). With advancements in robotics technology, phased array probes can be mounted on manipulators to autonomously inspect complex curved structures in water-immersed environments, enhancing both inspection capacity and efficiency. Conventional Delay-And-Sum (DAS) based imaging techniques require prior knowledge of the structure’s surface geometry and the relative position of the probe. The acoustic path with the shortest time of flight is then determined based on Fermat’s principle. However, the inspection Pulse Repetition Frequency (PRF) and the number of pixels are constrained due to the computational cost of the acoustic path searching and DAS operations. Although several optimization methods have been proposed to accelerate or bypass the searching process, inspection performance remains limited by DAS operations. Alternatively, recursive non-stationary phase shift migration based imaging method have been developed to eliminate DAS operations, but their efficiency remains unsatisfactory. In this paper, we propose an adaptive wavenumber domain plane wave imaging method that enables real-time online imaging with fine spatial resolution. Each imaging cycle contains a group of emission events. In the first imaging cycle, conventional wavenumber domain plane wave imaging is employed to reconstruct the surface geometry as an initialization step. From the second imaging cycle onward, the emission focal law is dynamically adjusted based on the reconstructed surface geometry from the latest previous cycle, enabling the generation of steered plane wavefronts beneath the curved couplant-specimen interface. Once the scattering echoes are captured, non-stationary phase shift migration techniques are applied to simultaneously reconstruct both the surface geometry and the scattering wavefield beneath the specimen surface. Finally, the wavenumber domain f-k migration method is utilized to reconstruct inspection images with high computational efficiency. Simulations were conducted to validate the proposed method. The real-time online imaging frame rate exceeds 45 fps, with about 200 thousands pixels in the ROI, demonstrating the potential of the proposed method for automated industrial online NDT&E.