Cross Subaperture Averaging Generalized Sidelobe Canceler Beamforming Applied to Medical Ultrasound Imaging

Jin Yang,Jiaqi Xi,Xiaodong Chen,Yi Wang,Jiake Li,Huaiyu Cai

doi:10.3390/app11188689

Abstract

For adaptive ultrasound imaging, a reliable estimation of the covariance matrix has a decisive influence on the performance of beamformers. In this paper, we propose a new cross subaperture averaging generalized sidelobe canceler approach (GSC-CROSS) for medical ultrasound imaging, which uses the cross-covariance matrix instead of the traditional covariance matrix estimation. By using the more stable and accurate estimation of the covariance matrix, GSC-CROSS performs well in both lateral resolution and contrast. Experiments are conducted based on the simulated echo data of scattering points and a cyst target. Beamforming responses of scattering points show that GSC-CROSS can improve the lateral resolution by 76.9%, 68.8%, and 17.1% compared with delay-and-sum (DS), synthetic aperture (SA), and the traditional generalized sidelobe canceler (GSC), respectively. Also, imaging of the cyst target shows that compared with DS, SA, and GSC, the contrast increases by 101%, 32.6%, and 63.5%, respectively. Finally, the actual echo data collected from a medical ultrasonic imaging system is applied to reconstruct the image. Results show that the proposed method has a good performance on lateral resolution and contrast. Both the simulated and experimental data demonstrate the effectiveness of the proposed method.

Highlights

Medical ultrasound imaging has the characteristics of high transmission capacity and low harm to the human body, which plays an important role in medical diagnosis technologies [1,2,3]
We present several results including simulated and experimental data to compare the difference between the proposed method with DS, synthetic aperture (SA), and Generalized Sidelobe Canceler (GSC) in terms of lateral resolution, contrast, and sidelobe level
The experimental data is collected from a medthe experimental data is collected from a medical ultrasound imaging system with the ical ultrasound imaging system with the same parameters as the simulated one

Summary

Introduction

Medical ultrasound imaging has the characteristics of high transmission capacity and low harm to the human body, which plays an important role in medical diagnosis technologies [1,2,3]. The DS suffers wide main lobe and high sidelobe, which makes the lateral resolution and contrast of the image poor [5]. Though SA can improve the lateral resolution and contrast, the sidelobe is still at a high level [7]. We use adaptive beamformers to process ultrasonic data that has achieved transmitted and received focusing by SA. X(k) consists of M time-delayed echo data, X(k) =. Where S(k) represents the desired signal, which is reflected by the detection point, I(k) is the echo signal introduced from the sidelobe direction called interference signal, and N(k) represents the noise signal, including thermal noise and scattering noise. The weight vector ω(k) is equivalent to a spatial filter, which can suppress interference and noise signals while retaining the desired signal

Methods

Results

Discussion

Conclusion