【作者】 田勇；

【导师】 赵丽红；

【作者基本信息】 东北大学 ， 生物医学工程， 2017， 硕士

【摘要】 研究发现,在MATLAB算法仿真中可以同时形成两个或者多个超声聚焦点,因此利用电子系统控制各个阵元的发射延迟时间和激励幅度可以实时形成两个或者多个焦点。在传统一维线阵超声相控阵单焦点的研究中,需要改变各个阵元发射延迟数据以形成第二个焦点,在临床实际治疗中,单焦点模式治疗会花费较长的时间,延长患者不必要的疼痛。因此本论文的研究重点是在现有的理论基础上,采用超声相控阵聚焦技术,实现基于FPGA的超声相控阵一维线阵多聚焦点的硬件系统。首先,论文分析了超声相控阵聚焦技术的国内外研究现状,认识到要进行超声相控阵一维线阵多聚焦点的研究与设计,必须对超声相控阵发射聚焦和发射延迟时间精度有很好的掌握,所以论文首先对超声相控阵聚焦技术进行了研究,分析了现有的超声相控阵多聚焦点技术理论的可行性。本文在查阅大量文献基础上,提出了基于FPGA的超声相控线阵多聚焦点硬件系统的设计方案,利用超声相控阵聚焦技术同时形成两个或多个聚焦点进行研究。根据超声换能器内各个阵元的参数,利用MATLAB软件对特定位置及深度的两个聚焦点进行仿真得到64阵元的不同发射延迟时间和激励幅度的数据,存储在FPGA芯片的ROM IP核中,根据超声成像软件对待检测区域选取靶点,将得到的两个聚焦点的位置及其深度信息数据下发给FPGA处理,FPGA调取ROM中的数据发射驱动信号给高压脉冲芯片,最终在指定位置形成两个或者多个实时聚焦点。其次,论文提出了超声相控阵多聚焦点发射系统的总体设计方案,包括USB3.0转FPGA接口电路、控制电路、驱动电路、探头转换板和ACDC电源方案。并根据设计方案利用Cadence软件完成了硬件电路的设计与实现,重点是对控制电路与驱动电路的设计,接着利用Quartus Ⅱ软件完成了逻辑代码设计。为后续验证基于新方案系统的超声相控阵多焦点聚焦性能搭建起了硬件平台。最后,对设计的驱动电路进行了测试与分析,并搭建系统硬件平台,利用声场扫描仪对新系统进行了声场扫描验证。验证结果:新系统形成的超声多聚焦点与预期的理论值相符。更多还原

【Abstract】 It is found that two or more ultrasonic focus points can be formed simultaneously in the simulation of MATLAB algorithm,therefore,two or more focal points can be formed in real time by using the electronic system to control the emission delay time and excitation amplitude of each element.In the traditional one-dimensional linear array ultrasound phased array single focus study,the need to change the array of firing delay data to form a second focus in clinical practice,the treatment of single-focus mode will take a long time to extend the patient’s unnecessary pain.Therefore,the focus of this paper is to apply ultrasonic phased array focusing technology to realize the hardware system of one-dimensional linear array multi-focal point of ultrasonic phased array based on FPGA under the existing theory.First of all,this paper analyzed the research status of ultrasonic phased array focusing technology at home and abroad,and recognizes that the research and design of one-dimensional linear array multi-focal point system for ultrasonic phased array must be focused on ultrasonic phased array emission and the delay time.So the paper focuses on ultrasonic phased array focusing technology,and analyzes the feasibility of the existing multi-focus theory of ultrasonic phased array.In this paper,based on the large amount of literature,the design scheme of multi-focus system based on FPGA is proposed.Based on the parameters of each element in the ultrasonic transducer,MATLAB software is used to simulate the two focal points of the specific position and depth.The data of the different launch delay time and excitation amplitude of the 64 element are stored in the ROM IP core of the FPGA chip,according to the ultrasonic imaging software to select the target region to be detected,the location of the two focal points and the depth of the information sent to the FPGA processing,FPGA compared to ROM data transfer drive signal to the high-voltage pulse chip,the final respective designated positions form two focus points.Secondly,the paper presents the overall design of the multi-focus system of ultrasonic phased array,including USB3.0 to FPGA interface board,control circuit,drive circuit scheme,transducer conversion board and ACDC power supply.The design and implementation of the hardware circuit was completed by using Cadence software.The most important part is the design of control circuit and driver circuit.Then the logic code was designed by using Quartus Ⅱ software.The hardware platform was built for the follow-up verification of the performance of the multi-focus focusing of the ultrasonic phased array based on the new scheme system.Finally,the driving circuit of the system was tested and analyzed,and the system hardware platform was set up.The new system was verified by acoustic field scanning.The results show that the new multi-focus points of ultrasound system was consistent with the expected theoretical value.更多还原