Wang Yadan, Zheng Chichao, Wang Yuanguo, Feng Shuai, Liu Mingzhou, Peng Hu
School of Mechanical Engineering, Hefei University of Technology, Hefei, Anhui, China.
Department of Biomedical Engineering, Hefei University of Technology, Hefei, Anhui, China.
Technol Health Care. 2023;31(2):747-770. doi: 10.3233/THC-220450.
Pixel-based beamforming realizes dynamic focusing at the pixel level with a focused beam by assuming that the received signals are composed of spherical pulses. Far-focused pixel-based (FPB) imaging was proposed to avoid artifacts around the focal depth. However, the contrast improvement is limited.
We propose an adaptive weighting method based on dynamic phase coherence factor (DPCF) to improve the image contrast while preserving the speckle pattern.
The phase variation is dynamically estimated based on the noise energy proportion of echo signals and it is used to calculate phase coherence weights for suppressing interference and preserving desired signals. A depth-dependent parameter is designed for DPCF to enhance the performance of noise and clutter suppression in the far-field region. We further use the subarray averaging technique to smooth the speckle texture.
The proposed method was evaluated on simulated, phantom experimental, and in vivo data. Results show that, compared with the phase coherence factor (PCF) based method, DPCF respectively leads to average CR improvements by more than 60% and 24% in simulation and experiment, while obtaining an improved speckle signal-to-noise ratio.
The proposed method is a potentially valuable approach to obtaining high-quality ultrasound images in clinical applications.
基于像素的波束形成通过假设接收到的信号由球面脉冲组成，在像素级别实现动态聚焦并形成聚焦波束。提出了远场聚焦像素成像（FPB）以避免焦深附近的伪像。然而，对比度的改善是有限的。
我们提出一种基于动态相位相干因子（DPCF）的自适应加权方法，以在保留散斑图案的同时提高图像对比度。
基于回波信号的噪声能量比例动态估计相位变化，并用于计算相位相干权重，以抑制干扰并保留所需信号。为DPCF设计了一个深度相关参数，以增强远场区域的噪声和杂波抑制性能。我们进一步使用子阵列平均技术来平滑散斑纹理。
在模拟、体模实验和体内数据上对所提出的方法进行了评估。结果表明，与基于相位相干因子（PCF）的方法相比，DPCF在模拟和实验中分别使平均对比度分辨率提高了60%以上和24%，同时获得了改善的散斑信噪比。
所提出的方法是在临床应用中获得高质量超声图像的一种潜在有价值的方法。
