Forward-backward generalized sidelobe canceler beamforming applied to medical ultrasound imaging

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

doi:10.1063/1.4974247

Abstract

For adaptive ultrasound imaging, accurate estimation of the covariance matrix is of great importance, and it has a fundamental influence on the performance of the adaptive beamformer. In this paper, a new forward-backward generalized sidelobe canceler (FBGSC) approach is proposed for medical ultrasound imaging, which uses forward and backward subaperture averaging to accurate estimate the covariance matrix. And resulted from accurate estimating of covariance matrix, FBGSC can achieve better lateral resolution and contrast without preprocessing algorithms. Field II is applied to obtain the simulated echo data of scattering points and a circular cyst. Beamforming responses of scattering points show that FBGSC can improve the lateral resolution by 55.7% and 66.6% compared with synthetic aperture (SA) and delay-and-sum (DS), respectively. Similarly, the simulated results of circular cyst show that FBGSC can obtain better beamforming responses than traditional adaptive beamformers. Finally, an experiment is conducted based on the real echo data of a medical ultrasound system. Results demonstrate that the FBGSC can improve the imaging quality of medical ultrasound imaging system, with lower computational demand and higher reliability.

Highlights

Medical ultrasound imaging with characteristics of high transmission capacity and low harm to human body has become one of the major medical diagnostic technologies nowadays, and imaging algorithms are the key technology of the medical ultrasound imaging system.[1]
We put forward a new forward-backward generalized sidelobe canceler (FBGSC) approach for medical ultrasound imaging, which uses forward and backward subaperture averaging to accurate estimate covariance matrix, and by using the new more stable and accurate covariance matrix instead of the traditional forward subaperture averaging one leads to excellent echo images without preprocessing algorithms
We will provide several examples to compare the performance of the proposed beamformer with Generalized sidelobe canceler (GSC), GSC+time smoothing, GSC+diagonal loading (DL), synthetic aperture (SA) and DS beamformers in terms of lateral resolution and contrast

Summary

Introduction

Medical ultrasound imaging with characteristics of high transmission capacity and low harm to human body has become one of the major medical diagnostic technologies nowadays, and imaging algorithms are the key technology of the medical ultrasound imaging system.[1]. DS has characteristics of low signal-noise ratio (SNR), low contrast and wide mainlobe.[2] In order to improve the beamforming response, Jørgen Arendt Jensen[3] proposed synthetic aperture (SA) beamforming, SA will achieve focusing during transmitting and receiving for every point in the whole field, improves the contrast and lateral resolution of system, it still suffers from high level of sidelobe energy. The calculated weights are equivalent to spatial filter which will maintain the desired signal and suppress the interference and noise signal of the echo data. It improves the SNR of echo imaging. Equation for LRI will be (2), and xm(k) is the echo data of m’s element

Methods

Results

Conclusion