title: Sigma-delta receive beamformer based on cascaded reconstruction for ultrasound imaging application.
abstract: A pre-delay reconstruction sigma-delta beamformer (SDBF) was recently proposed to achieve a higher level of integration in ultrasound imaging systems. Nevertheless, the high-order reconstruction filter used in each channel of SDBF makes the beamformer highly complex. The beamformer can be simplified by reconstructing the signal after the delay-and-sum process with only one filter. However, this post-delay reconstruction-based design degrades image quality when dynamic focusing is performed. This paper shows that employing a simple pre-delay filter is sufficient to achieve similar performance as conventional pre-delay reconstruction SDBF, as long as the pre-delay filter provides the required pre-delay signal to-quantization noise ratio (SQNR). Based on this finding, we proposed a cascaded reconstruction beamformer that uses a boxcar filter as the pre-delay filter in each channel. Simulations using real phantom data demonstrate that the proposed beamforming method can achieve a contrast resolution comparable to that of the pre-delay reconstruction beamforming method. In addition, the hardware can be greatly simplified compared with the pre-delay reconstruction beamformers.
authors.affiliation: Division of Circuits and Systems, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore. cheo0030@ntu.edu.sg
authors.forename: Jia Hao
authors.initials: JH
authors.lastname: Cheong
authors.forename: Yvonne Ying Hung
authors.initials: YY
authors.lastname: Lam
authors.forename: Kei Tee
authors.initials: KT
authors.lastname: Tiew
authors.forename: Liang Mong
authors.initials: LM
authors.lastname: Koh
mesh_terms: D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation*