超声阵列成像算法研究及实现

发布时间：2018-07-16 14:06

【摘要】：超声相控阵成像技术具有波束控制灵活、检测范围大、检测结果直观等特点,在工业无损检测领域具有广泛地应用。本文旨在研究超声相控阵声场与波束形成算法,在此基础上研制一台64通道超声相控阵检测系统。主要的工作如下:1.研究了超声相控阵基本原理、扫查方式。研究了单个矩形换能器和线性换能器阵列的声场计算方法,分析了延时精度对合成波束的误差旁瓣、偏转和聚焦精度的影响。2.研究了超声波束形成算法,基于数字波束形成技术研究了高精度延时的实现算法,包括基于分数时延滤波器和基于相位旋转的波束形成算法。3.研究了超声编码激励技术,分析了编码激励系统的性能指标。研究了常用的二进制编码序列,提出了编码激励的发射波形设计方法。4.提出了基于频域信道估计的超声信号检测算法,通过类比无线通信中的多径信道理论,在传统超声编码激励的基础上采用带循环前缀的Zadoff-Chu序列通过频域处理实现理想的脉冲压缩效果。5.设计了64通道超声相控阵检测成像系统,基于模块化的设计方案,完成了信号发射板、信号接收和处理板、系统控制板等板卡的硬件设计。在硬件平台的基础上,完成了超声发射波束形成、多通道高速LVDS信号接收、动态聚焦与接收波束形成、系统控制、总线传输等模块的FPGA设计。
[Abstract]:Ultrasonic phased array imaging technology has been widely used in the field of industrial nondestructive testing because of its flexible beam control, wide detection range and intuitive detection results. In this paper, the sound field and beamforming algorithm of ultrasonic phased array are studied, and a 64 channel ultrasonic phased array detection system is developed. The main work is as follows: 1. The basic principle and scanning mode of ultrasonic phased array are studied. The acoustic field calculation method of single rectangular transducer and linear transducer array is studied. The influence of delay precision on the error sidelobe, deflection and focusing accuracy of composite beam is analyzed. The ultrasonic beamforming algorithm and the high precision delay algorithm based on digital beamforming are studied, including fractional delay filter and beamforming algorithm based on phase rotation. The ultrasonic coding excitation technology is studied, and the performance index of the coded excitation system is analyzed. In this paper, the binary coding sequences are studied, and the design method of transmitting waveform with encoding excitation is put forward. An ultrasonic signal detection algorithm based on frequency domain channel estimation is proposed. The Zadoff-Chu sequence with cyclic prefix is used to realize the ideal pulse compression effect by frequency domain processing based on the traditional ultrasonic coding excitation. A 64 channel ultrasonic phased array imaging system is designed. Based on the modular design, the hardware design of signal transmitting board, signal receiving and processing board, system control board and so on is completed. Based on the hardware platform, the FPGA design of ultrasonic beamforming, multi-channel high-speed LVDS signal receiving, dynamic focusing and receiving beamforming, system control, bus transmission and so on has been completed.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB559;TP391.41

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