Echography using correlation techniques: choice of coding signal
Echography using correlation techniques: choice of coding signal
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使用相关技术的回波描记术：编码信号的选择
DOI：
10.1109/58.308492
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
W. Urbach
中科院分区：
文献类型：
--
作者：
M. A. Benkhelifa;M. Gindre;J. Le Huerou;W. Urbach
20世纪80年代初，S的理论研究表明，利用相关技术的超声成像可以克服经典脉冲超声成像的一些缺点。实际上，通过发送连续的编码信号，然后在接收器将其压缩成短的、高分辨率的脉冲，总的信噪比(SNR)得到了改善。通过发射信号和接收信号的互相关来确定目标位置。通过提高SNR，频带压缩允许恢复隐藏在接收器噪声中的回波信号。因此，在医用类型的超声成像中，固定深度的信号衰减与频率成正比，信噪比的提高允许使用更高频率的信号，并导致分辨率的提高。本文报道了用经典脉冲回波和相关技术获得的简单回波B型图像的对比实验研究结果。由于编码信号的优化在相关技术的性能中起着至关重要的作用，因此我们还将对最常见的码(m序列和互补序列)的性能进行比较研究。我们将特别强调以下几点：与成像系统的动态直接相关的相关函数的旁瓣相比，中央叶的相对重要性，与系统的轴向分辨率直接相关的相关峰的宽度，实现的便利性。将讨论用编码信号获得的B模式图像的优点，表明只要使用信号调制，用周期m序列获得的效果最好。
Theoretical studies made in the early 1980's suggest that ultrasonic imaging using correlation technique can overcome some of the drawbacks of classical pulse echography. Indeed by transmitting a continuous coded signal and then compressing it into a short, high resolution pulse at the receiver the total signal to noise ratio (SNR) is improved. The target location is determined by cross correlation of the emitted and the received signal. The band compression allows, by increasing SNR, the retrieval of echo signals buried in the receiver noise. Thus in medical-type echography, where the signal attenuation at fixed depth is proportional to the frequency, the SNR improvement allows the use of higher frequency signals and leads to improved resolution. We report here the results of comparative experimental studies of simple echo B type images as obtained by the classical pulse echo and correlation techniques. Because the optimisation of the coded signal plays a crucial role in the performance of the correlation technique we will also present a comparative study of the performances of the most common codes (m-sequences and complementary series). In particular we shall emphasise the following points: the relative importance of the central lobe as compared to the side lobes of the correlation function, which is directly related to the dynamic of the imaging system, the width of the correlation peak which is directly related to the axial resolution of the system, the facility of the realisation. The merit of B-mode images obtained with the coded signals will be discussed showing that as far as signal modulation is used the best results are obtained with periodic m-sequences.<<ETX>>