Work

High resolution ultrasonic imaging of extended targets via combined match field and time delay beamforming

Year: 2024

Type: article

Abstract: • Combined match field and time delay beamformers enable accurate ultrasonic imaging of extended targets that are notoriously challenging in conventional imaging. • Broadband coherent white noise constraint algorithm achieves high azimuth resolution comparable to MUSIC type beamformers without subspace decomposition. • Dynamic range bias offers superior image contrast to track lateral extension of extended targets. • Wave mode reception consideration increases array gain in match field beamforming. Ultrasound imaging using an active sensing array has been extensively studied in both time domain and frequency domain. Subspace decomposition methods in match field beamforming such as the multiple signal classification (MUSIC) algorithm can achieve subwavelength resolution of distinct point scatterers. However, when the size of the target is on the order of one wavelength or larger, the MUSIC type algorithms suffer from poor performance due to a tangled eigen structure. This paper proposes an adaptive match field beamformer that does not require subspace decomposition to achieve high resolution imaging of extended targets. Specifically, the broadband coherent white noise constraint (C-WNC) algorithm is utilized to achieve high focusing ability of extended targets by exploiting the cross-frequency coherence in an active sensing scheme. The dynamic range bias in the adaptive beamformer benefits the C-WNC algorithm to achieve high contrast regardless of the SNR. Both simulations and experiments show that the C-WNC images retain their resolution cells on the tips of the extended target with sizes ranging from a wavelength to sizes as large as the physical aperture width. A robust imaging scheme is then proposed to obtain high quality images by combining C-WNC images with a statistically stable delay-multiply-and-sum (DMAS) algorithm to create high-contrast and high-resolution images of extended targets in both azimuth and axial range directions.

Source: Ultrasonics

DOI: 10.1016/j.ultras.2024.107464

Authors: Chengyang Huang, Francesco Lanza di Scalea

Institution: University of California San Diego

Language: English

Topic: Direction-of-Arrival Estimation Techniques

Subfield: Signal Processing

Field: Computer Science

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,560

Funder: Federal Railroad Administration