Eigenspace-Based Generalized Sidelobe Canceler Beamforming Applied to Medical Ultrasound Imaging.

Jiake Li,Xiaodong Chen,Daoyin Yu,Wei Li,Yi Wang

doi:10.3390/s16081192

Abstract

The use of a generalized sidelobe canceler (GSC) can significantly improve the lateral resolution of medical ultrasound systems, but the contrast improvement isn’t satisfactory. Thus a new Eigenspace-based generalized sidelobe canceler (EBGSC) approach is proposed for medical ultrasound imaging, which can improve both the lateral resolution and contrast of the system. The weight vector of the EBGSC is obtained by projecting the GSC weight vector onto a vector subspace constructed from the eigenstructure of the covariance matrix, and using the new weight vector instead of the GSC ones leads to reduced sidelobe level and improved contrast. Simulated and experimental data are used to evaluate the performance of the proposed method. The Field II software is applied to obtain the simulated echo data of scattering points and circular cysts. Imaging of scattering points show that EBGSC has the same full width at half maximum (FWHM) as GSC, while the lateral resolution improves by 35.3% and 52.7% compared with synthetic aperture (SA) and delay-and-sum (DS), respectively. Compared with GSC, SA and DS, EBGSC improves the peak sidelobe level (PSL) by 23.55, 33.11 and 50.38 dB, respectively. Also the cyst contrast increase by EBGSC was calculated as 16.77, 12.43 and 26.73 dB, when compared with GSC, SA and DS, respectively. Finally, an experiment is conducted on the basis of the complete echo data collected by a medical ultrasonic imaging system. Results show that the proposed method can produce better lateral resolution and contrast than non-adaptive beamformers.

Highlights

Medical ultrasound imaging, with its characteristics of high transmission capacity and low harm to the human body has become one of the major medical diagnostic technologies nowadays, and imaging algorithms are the key technology of medical ultrasonic imaging [1]
We will provide several examples to compare the performance of the proposed beamformer with generalized sidelobe canceler (GSC), synthetic aperture (SA) and DS in terms of lateral resolution, contrast and sidelobe levels
Is a simulation tool widely used in the medical ultrasonic imaging field, and the simulation echo data obtained by Field II can be used as original data to verify the imaging performance of the algorithm

Summary

Introduction

With its characteristics of high transmission capacity and low harm to the human body has become one of the major medical diagnostic technologies nowadays, and imaging algorithms are the key technology of medical ultrasonic imaging [1]. SA can equivalently achieve focusing during transmission and reception for every point at the same time in the whole field, and it improves the SNR and lateral resolution of the system, it still has a high level of sidelobe energy. For adaptive beamformers the weight vector wpkq is calculated from Xpkq, and varies with the echo data. An ideal weight vector wpkq corresponds to a spatial filter, which can maintain the desired signal while suppressing the interference and noise signals of the echo data. It enhances the image quality of the medical ultrasound system

Methods

Results

Discussion

Conclusion