激光与光电子学进展, 2019, 56 (14): 141101, 网络出版: 2019-07-12
基于编码激励和相干系数的内镜超声成像算法 下载: 1199次
Ultrasound Endoscopic Imaging Algorithm Based on Coded Excitation and Coherence Factor
成像系统 内镜超声成像 编码激励 Golay互补序列对 相干系数 合成孔径 imaging systems endoscopic ultrasound imaging coded excitation pair of Golay complementary sequences coherence factor synthetic aperture
摘要
合成孔径算法可以实现超声波发射和接收的双向动态聚焦,从而提高成像分辨率,但仍存在图像信噪比低,旁瓣明显等问题。为进一步提高超声成像质量,提出一种基于编码激励和相干系数的合成孔径超声成像(CFCS)算法。首先采用Golay互补序列对作为激励信号,通过增加发射脉冲的编码长度提高图像的信噪比,同时利用序列对良好的自相关特性消除距离旁瓣,提高图像的轴向分辨率。在此基础上引入相干系数,对图像中的横向旁瓣加以抑制。仿真结果表明,相较于基于Barker编码激励的合成孔径算法,CFCS算法可以有效消除距离旁瓣,轴向分辨率提升了47.4%;相较于相干系数合成孔径算法,CFCS算法在轴向分辨率上提升了31%,信噪比提升约18 dB。
Abstract
The synthetic aperture algorithm can achieve bidirectional dynamic focusing of ultrasound transmission and reception, thus improving imaging resolution; however, some problems still exist such as low image signal-to-noise ratios (SNRs) and obvious side lobes. To further improve the quality of ultrasound imaging, this study proposes a synthetic aperture ultrasound imaging algorithm called coherence factor and complementary sequences (CFCS) based on coded excitation and coherence factor. First, a pair of Golay complementary sequences are adopted as the excitation signal, and the SNR of the image is increased by increasing the coding length of the transmitted pulse. Simultaneously, the good autocorrelation characteristics of complementary sequences are exploited to eliminate the distance side lobes; thus, the axial resolution of the image is improved. In addition, a coherence factor is introduced to suppress the lateral side lobes in the image. The simulations indicate that, compared with the synthetic aperture algorithm based on Barker coded excitation, the CFCS algorithm can effectively eliminate the distance side lobes; the axial resolution is also improved by 47.4% using the CFCS algorithm. Furthermore, compared with the synthetic aperture algorithm based on coherence factor, the CFCS algorithm's axial resolution and SNR increase by 31% and ~18 dB, respectively.
邓惟心, 陈晓冬, 杨晋, 吉佳瑞, 汪毅, 蔡怀宇. 基于编码激励和相干系数的内镜超声成像算法[J]. 激光与光电子学进展, 2019, 56(14): 141101. Weixin Deng, Xiaodong Chen, Jin Yang, Jiarui Ji, Yi Wang, Huaiyu Cai. Ultrasound Endoscopic Imaging Algorithm Based on Coded Excitation and Coherence Factor[J]. Laser & Optoelectronics Progress, 2019, 56(14): 141101.