超声平面波同相正交信号频域波束形成算法

针对频域平面波波束形成算法尚不能直接应用于采用正交解调的超声成像系统中的实际问题,提出一种平面波同相正交信号频域波束形成方法。以平面波射频信号频域波束形成算法为基础,根据射频信号与同相正交信号波数空间变量之间的关系,推导了平面波同相正交信号与对应图像的频谱映射表达式,从而实现对正交解调后信号的频域超声图像重建。采用2016年Plane Wave Imaging Challenge in Medical Ultrasound (PICMUS)发布的仿真、仿体及在体原始回波数据对这一方法进行验证,并评估图像的分辨率和对比噪声比。仿真和仿体实验结果表明,相对于射频信号的频域波束形成算法,该算法可获得与之相同的图像质量,并将成像速度提高了约4倍。在体实验数据的成像结果也验证了该算法在实际应用中的有效性。 

Fourier-based ultrasound plane wave beamforming using in-phase and quadrature data

The Fourier-based plane wave beamforming methods were developed in Radio Frequency(RF) signal cannot be directly applied to the ultrasonic imaging system using quadrature demodulation.In order to tackle this problem,a Fourier-based plane wave beamforming method is extended to In-phase and Quadrature(IQ) data imaging.According to the spectrum relation between RF and IQ signal,the spectrum remapping function between the demodulated IQ prebeamformed data and the beamformed IQ image is derived.Thus the beamformed image could be directly reconstructed in frequency domain using IQ signal.The performance of the proposed approach was evaluated in terms of resolution and Contrast to Noise Ratio(CNR) using the data published in Plane Wave Imaging Challenge in Medical Ultrasound(PICMUS) in 2016.Numerical simulation and phantom experiment results show that the proposed IQ approach can increase the imaging speed by 4 times with comparable image resolution and CNR.In-vivo experimental results also confirm the validity of the proposed method in real applications.