摘要
针对超声组织谐波成像中宽带射频回波信号的谐波分离问题,提出了一种基于逐次变分模态分解(SVMD)和经验小波变换(EWT)的信号滤波算法,简称SVMD-EWT。其对信号进行逐次变分模态分解,收集窄带模态的中心频率。结合经验小波变换中自适应频谱曲线局部极小值寻找方法对模态进行分类。将判定为基波成分与谐波成分相互混叠的模态的能量作为优化经验小波变换模态边界的参数,设计经验小波滤波器对超声射频回波信号做滤波处理。仿真和实验表明相比传统的人为给定截止频率的带通滤波器和将发射反相位信号得到的回波信号相加滤波的脉冲反转法,本文提出的方法具有更好的滤波性能和稳定性。带通滤波器和本文方法滤波后生成的乳腺肿瘤谐波B超图对比度分别为15.77 dB和20.78 dB。
A signal filtering algorithm(SVMD-EWT)based on successive variational mode decomposition and empirical wavelet transform is proposed to solve the harmonic separation problem of wideband RF echo signal in ultrasonic tissue harmonic imaging.The signal is decomposed by successive variational modes to acquire the center frequencies of narrow-band modes.The modes are classified according to the local minimum found by Scale-space in empirical wavelet transform.The energy of the modes aliasing in fundamental and harmonic components is chosen as the parameter to optimize the mode boundary of the empirical wavelet transform.Then the empirical wavelet filter is designed to filter the ultrasonic RF echo signals.Simulation and experiments show that the proposed method has better filtering performance than the traditional high-pass filter method with artificially given cutoff frequency and the pulse inversion method dealing with paired echo signals generated by transmitting the inverse phase signal.The contrast of the harmonic breast ultrasound images generated after bandpass filtering and the method proposed in this study are 15.77 dB and 20.78 dB,respectively.
作者
范淼淼
赖宁磊
晏张平
林伟军
刘晓宙
Fan Miaomiao;Lai Ninglei;Yan Zhangping;Lin Weijun;Liu Xiaozhou(Key Laboratory of Modern Acoustics,Collaborative Innovation Center of Advanced Microstructures,Institute of Acoustics and School of Physics,Nanjing University,Nanjing 210093,China;Chengdu HEUK Medical Equipment Co.,Ltd.,Chengdu 610041,China;State Key Laboratory of Acoustics,Institute of Acoustics,Chinese Academy of Sciences,Beijing 100190,China)
出处
《仪器仪表学报》
EI
CAS
CSCD
北大核心
2024年第6期231-239,共9页
Chinese Journal of Scientific Instrument
基金
国家重点研发计划项目(2020YFA0211400)
国家自然科学基金(12174192)
声场声信息国家重点实验室(SKLA202410)项目资助。
关键词
组织谐波成像
谐波分离
变分模态分解
经验小波变换
tissue harmonic imaging
harmonic separation
successive variational mode decomposition
empirical wavelet transform
