Cincotti G, Cardone G, Gori P, Pappalardo M
Dipt. di Ingegneria Elettronica, Rome Univ.
IEEE Trans Ultrason Ferroelectr Freq Control. 1999;46(6):1450-8. doi: 10.1109/58.808869.
A high performance ultrasound imaging system requires accurate control of the amplitude of the array elements, as well as of the time delays between them, both in the transmit and receive modes. In transmission, conventional array aperture windowing implies a different driving voltage for each element of the array, an expensive solution for systems with a large number of channels. In this paper, we present a simple, versatile, and inexpensive beamforming method that operates the aperture windowing in the transmit mode, simply controlling the lengths of the electric pulses driving the array elements. Computer simulations and experimental measurements are presented for different types of arrays. They confirm that the proposed beamforming technique improves the contrast resolution of the imaging system, reducing the off-axis intensity of the radiated field pattern. Moreover, the axial resolution is slightly enhanced, because the overall length of the transmitted ultrasonic pulse is reduced.
高性能超声成像系统在发射和接收模式下都需要精确控制阵列元件的幅度以及它们之间的时间延迟。在发射过程中，传统的阵列孔径窗技术意味着对阵列的每个元件施加不同的驱动电压，对于具有大量通道的系统来说，这是一种昂贵的解决方案。在本文中，我们提出了一种简单、通用且廉价的波束形成方法，该方法在发射模式下操作孔径窗，只需控制驱动阵列元件的电脉冲长度即可。针对不同类型的阵列进行了计算机模拟和实验测量。结果证实，所提出的波束形成技术提高了成像系统的对比度分辨率，降低了辐射场模式的离轴强度。此外，轴向分辨率略有提高，因为发射超声脉冲的总长度缩短了。
