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用于消化道诊断的超声内镜成像系统设计
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Abstract:
针对消化道疾病的精准诊断需求,本文设计并实现了一种高集成度的超声内镜成像系统。采用中心频率20 MHz的PMN-PT单阵元聚焦超声换能器,实现超声信号与电信号的转换。以FPGA为系统控制和处理核心,负责超声波的发射、采集及数据处理功能。提出了一种结合了深度线性增益补偿与分段增益调节的TGC控制方案,以补偿深度衰减造成的回波信号能量损失。补偿后的回波信号经数字滤波处理后,通过希尔伯特变换与CORDIC算法进行正交解调和包络检波,经USB3.0接口传输至上位机进行实时图像显示。在MATLAB上分析回波数据以判断系统性能。实验结果表明,系统的脉冲发射与信号采集符合预设参数,回波数据无失真。在TGC处理后,深度方向的信号均衡性显著提升,背景噪声明显减少,成像更加清晰,能够精准反映被测物体的结构特征。系统设计合理、功能完善,分辨率达到50 μm,能够有效支持消化道疾病的高精度诊断,具有潜在的临床应用价值。
In response to the need for accurate diagnosis of gastrointestinal diseases, this paper presents the design and implementation of a highly integrated ultrasound endoscopic imaging system. The system utilizes a 20 MHz PMN-PT single-element focused ultrasound transducer to convert ultrasonic signals into electrical signals. An FPGA serves as the core control and processing unit, responsible for ultrasound wave transmission, reception, and data processing. A novel TGC control scheme combining depth-dependent linear gain compensation with segmental gain adjustment is proposed to compensate for the signal attenuation caused by depth. The compensated echo signals are digitally filtered, followed by orthogonal demodulation and envelope detection using Hilbert transform and CORDIC algorithm. The processed data is transmitted in real-time to a host computer for image display via USB3.0. Echo data is analyzed in MATLAB to evaluate system performance. Experimental results show that the system’s pulse transmission and signal acquisition meet predefined parameters, with no distortion in the echo data. After TGC processing, the signal uniformity in depth direction is significantly improved, background noise is substantially reduced, and the imaging becomes clearer, enabling precise reflection of the structural features of the measured object. The system is well-designed with complete functionality, achieving a resolution of 50 μm, which effectively supports high-precision diagnosis of gastrointestinal diseases and holds potential for clinical applications.
[1] | Yoon, S., Williams, J., Kang, B.J., Yoon, C., Cabrera-Munoz, N., Jeong, J.S., et al. (2015) Angled-Focused 45mhz PMN-PT Single Element Transducer for Intravascular Ultrasound Imaging. Sensors and Actuators A: Physical, 228, 16-22. https://doi.org/10.1016/j.sna.2015.02.037 |
[2] | Kidav, J., et al. (2021) Design of a 128‐Channel Transceiver Hardware for Medical Ultrasound Imaging Systems. IET Circuits, Devices & Systems, 16, 92-104. https://doi.org/10.1049/cds2.12087 |
[3] | Xu, J., Wang, N., Chu, T., Yang, B., Jian, X. and Cui, Y. (2022) A High-Frequency Mechanical Scanning Ultrasound Imaging System. Biosensors, 13, 32. https://doi.org/10.3390/bios13010032 |
[4] | 欧阳小龙. 医学超声成像的硬件系统设计[D]: [硕士学位论文]. 南京: 东南大学, 2022. |
[5] | 卢小星. 面向CMUT的超声成像电路设计与实现[D]: [硕士学位论文]. 太原: 中北大学, 2024. |
[6] | 陈谋, 何常德, 孟亚楠, 等. 面向电容式微机械超声换能器器件的32通道收发电路设计与测试[J]. 应用声学, 2022, 41(3): 436-446. |
[7] | 刘宝强. 高分辨率超声成像系统设计[D]: [硕士学位论文]. 赣州: 江西理工大学, 2014. |
[8] | 陆祖嘉, 邱维宝, 牟培田, 等. 基于现场可编程门阵列的高分辨率超声成像系统设计[J]. 中国医学物理学杂志, 2015, 32(6): 847-850. |
[9] | 周洁文, 李晓兵, 丁伟艳, 等. 皮肤囊肿成像用高频超声换能器及扫描方法[J]. 压电与声光, 2022, 44(1): 134-138. |