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超声成像的帧频是影响超声成像应用的一个关键因素,成像系统的帧频决定了系统捕捉运动组织的能力,如3D成像、心脏成像、彩色多普勒等。传统超声成像采用延迟聚焦方法可获得较好的图像,但成像帧频较低。目前提高超声成像帧频主要有平面波成像和宽波束激励成像两种方法。平面波成像是通过激励所有阵元同时发射并同时接收超声波,虽在帧频上获得了显著提高,但由于它使用非聚焦技术,分辨率的提高仍然比较有限,特别是当要维持较高帧率而使用较少的扫描角度时,得到的图像质量仍然不高。宽波束成像技术利用多阵元同时发射超声波、远点聚焦、动态实现孔径变迹等方法可极大地提高图像的帧频、均匀性和空间分辨率。文章通过美国Verasonics公司V-1数据采集系统采集宽波束数据,进行波束合成建立宽波束超声图像,并与平面波成像和传统聚焦成像技术进行了对比和分析。实验结果表明,相较于平面波成像和传统聚焦成像方法,宽波束成像具有更好的横向分辨率和轴向分辨率,且可获得比传统聚焦方法更高的帧频。
The frame rate of ultrasound imaging is a key factor affecting the application of ultrasound imaging. The frame rate of the imaging system determines the ability of the system to capture the movement tissue, such as 3D imaging, cardiac imaging, color Doppler and so on. Traditional ultrasound imaging using delayed focus method can get better images, but the imaging frame rate is low. At present, there are two main ways to improve the frame rate of ultrasound imaging: plane wave imaging and wide beam excitation imaging. Although the enhancement of the frame rate has been achieved by stimulating all elements to simultaneously launch and receive ultrasound simultaneously, the increase of resolution is still limited due to its use of non-focusing techniques, especially when the high frame rate is to be maintained When using less scanning angle, the image quality is still not high. Wide-beam imaging technology using multiple elements simultaneously transmit ultrasound, far-focus, dynamic aperture apodization and other methods can greatly improve the image frame rate, uniformity and spatial resolution. The article collects wide-beam data through the V-1 data acquisition system of Verasonics Corporation in the United States and performs beam synthesis to establish a wide-beam ultrasound image. The comparison and analysis are made with plane wave imaging and traditional focus imaging. The experimental results show that wide beam imaging has better lateral resolution and axial resolution than the traditional method of plane wave imaging and traditional focusing, and can obtain higher frame rate than the traditional focusing method.