Montaldo Gabriel, Palacio Delphine, Tanter Mickael, Fink Mathias
Laboratoire Ondes et Acoustique, Paris, France.
IEEE Trans Ultrason Ferroelectr Freq Control. 2005 Sep;52(9):1489-97. doi: 10.1109/tuffc.2005.1516021.
The design of two-dimensional (2-D) arrays for three-dimensional (3-D) ultrasonic imaging is a major challenge in medical and nondestructive applications. Thousands of transducers are typically needed for focusing and steering in a 3-D volume. In this article, we propose a different concept allowing us to obtain electronic 3-D focusing with a small number of transducers. The basic idea is to couple a small number of transducers to a chaotic reverberating cavity with one face in contact with the body of the patient. The reverberations of the ultrasonic waves inside the cavity create at each reflection virtual transducers. The cavity acts as an ultrasonic kaleidoscope multiplying the small number of transducers and creating a much larger virtual transducer array. By exploiting time-reversal processing, it is possible to use collectively all the virtual transducers to focus a pulse everywhere in a 3-D volume. The reception process is based on a nonlinear pulse-inversion technique in order to ensure a good contrast. The feasibility of this concept for the building of 3-D images was demonstrated using a prototype relying only on 31 emission transducers and a single reception transducer.
用于三维超声成像的二维阵列设计在医学和无损检测应用中是一项重大挑战。在三维容积中进行聚焦和扫描通常需要数千个换能器。在本文中，我们提出了一种不同的概念，使我们能够用少量换能器实现电子三维聚焦。基本思想是将少量换能器耦合到一个混沌混响腔，该腔的一个面与患者身体接触。腔内超声波的混响在每次反射时都会产生虚拟换能器。该腔充当超声万花筒，使少量换能器成倍增加，并创建一个大得多的虚拟换能器阵列。通过利用时间反转处理，可以共同使用所有虚拟换能器在三维容积中的任何位置聚焦一个脉冲。接收过程基于非线性脉冲反转技术，以确保良好的对比度。使用仅依赖31个发射换能器和单个接收换能器的原型证明了该概念用于构建三维图像的可行性。
