Beam domain adaptive beamforming using Generalized Side Lobe Canceller with coherence factor for medical ultrasound imaging

Abstract

As medical ultrasound (MU) signals are not stationary, the radiation pattern of the corresponding input data does not have a specific shape; thus, their reconstruction using Adaptive Beamformers (BF) becomes indispensable in order to improve the quality of the imaging system. Generalized Sidelobe Canceller (GSC) is a robust realization against clutter and interference, resulting from an elegant representation of Linearly Constrained Minimum Variance (LCMV) and Linearly Constrained Minimum Power (LCMP) BF. The MU imaging systems traditionally use larger array transducers which result in a larger element space. In this work, the beam domain GSC with coherence factor (BGSC-CF) was proposed in order to reduce the space dimension and consequently diminish computational complexity by exploring the transform matrix (T) properties. A Verasonics Vantage ultrasound system with a 6.25 MHz central frequency 128-element linear array transducer L11-4v was used to acquire the raw RF data from a multi-purpose tissue/cyst ultrasound phantom (Fluke model 84–317). For performance evaluation, the proposed method was compared with the techniques delay and sum (DAS), minimum variance (MV), GSC and eigenspace GSC (EGSC). Based on the obtained results it was possible to conclude that our proposed method BGSC-CF allows improvements in terms of array clutter suppression capabilities and it reveals to be robust in terms of anechoic cyst border definition when compared to the other techniques.