Schneider Fabio Kurt, Yoo Yang Mo, Agarwal Anup, Koh Liang Mong, Kim Yongmin
Image Computing Systems Laboratory, Department of Electrical Engineering, University of Washington, Seattle, WA 98195-2500, USA.
Ultrasonics. 2006 Jul;44(3):265-71. doi: 10.1016/j.ultras.2006.02.004. Epub 2006 Mar 6.
In this paper, we present a new quadrature demodulation filter to reduce hardware complexity in digital phase rotation beamforming. Due to its low sensitivity to phase delay errors, digital quadrature demodulation is commonly used in ultrasound machines. However, since it requires two lowpass filters for each channel to remove harmonics, the direct use of conventional finite impulse response (FIR) filters in ultrasound machines is computationally expensive and burdensome. In our new method, an efficient multi-stage uniform coefficient (MSUC) filter is utilized to remove harmonic components in phase rotation beamforming. In comparison with the directly implemented FIR (DI-FIR) and the previously-proposed signed-power-of-two FIR (SPOT-FIR) lowpass filters, the proposed MSUC filter reduces the necessary hardware resources by 93.9% and 83.9%, respectively. In simulation, the MSUC filter shows a negligible degradation in image quality. The proposed method resulted in comparable spatial and contrast resolution to the DI-FIR approach in the phantom study. These preliminary results indicate that the proposed quadrature demodulation filtering method could significantly reduce the hardware complexity in phase rotation beamforming while maintaining comparable image quality.
在本文中，我们提出了一种新的正交解调滤波器，以降低数字相位旋转波束形成中的硬件复杂度。由于其对相位延迟误差的低敏感性，数字正交解调常用于超声设备中。然而，由于每个通道需要两个低通滤波器来去除谐波，在超声设备中直接使用传统的有限脉冲响应（FIR）滤波器在计算上既昂贵又繁琐。在我们的新方法中，采用了一种高效的多级均匀系数（MSUC）滤波器来去除相位旋转波束形成中的谐波成分。与直接实现的FIR（DI-FIR）和先前提出的二的幂次符号FIR（SPOT-FIR）低通滤波器相比，所提出的MSUC滤波器分别减少了93.9%和83.9%的必要硬件资源。在模拟中，MSUC滤波器在图像质量上的下降可忽略不计。在体模研究中，所提出的方法在空间和对比度分辨率方面与DI-FIR方法相当。这些初步结果表明，所提出的正交解调滤波方法可以在保持相当图像质量的同时，显著降低相位旋转波束形成中的硬件复杂度。
