Study Of High-performance Synthetic Aperture Technique For Ultrasound Imaging

Synthetic aperture ultrasound imaging is a method of ultrasonic post-processing. It can synthesize small aperture imaging to large aperture imaging. And also by using the method of point by point focus, it makes the resolution of the image does not change with the change of location and depth. While using the same transducer, synthetic aperture imaging gets better resolution. As for the single-element transducers, the synthetic aperture technique can overcome some shortcomings, such as the restrictions in the depth of field in imaging and the low signal-to-noise ratio and low lateral resolution outside the range of the focus. The synthetic aperture technique can produce a depth independent lateral resolution, and improve the image quality of single-element transducers effectively.This major work of this paper is focusing on the synthetic aperture ultrasonic imaging method. They are divided into the following parts:(1)The synthetic aperture imaging algorithms has been researched, and some commonly used synthetic aperture imaging methods have been carried out with simulated data.(2)By using Field II simulation software, the scattering experiments and simulation experiments which use synthetic aperture focusing algorithm of the single-element focusing transducers and non-focusing transducers are achieved. And the lateral and axial resolutions of the scattering points are used to evaluate the image quality.(3)By using an FPGA-Based Open Platform for Ultrasound, the tungsten wire image data are collected by horizontal displacement platform, and the image is displayed directly in MATLAB, so as the images after processing by synthetic aperture focusing technology. By calculation the imaging resolution, experimental results are analyzed. Simultaneously, horizontal displacement of platforms collected ultrasonic echo data of intestines slice of a pig in vitro, then, displayed the image after processing by synthetic aperture focusing, and the results are used to compare with the image without using synthetic aperture focusing.(4)By using an FPGA-Based Open Platform for Ultrasound, the tungsten wire image data are collected by rotary platform, and image is displayed directly by MATLAB. And images which are processed by synthetic aperture focusing technology are also being displayed with MATLAB. imaging resolution are calculated and the results are being analyzed.(5)Ultra-fast ultrasonic imaging has been researched and simulation experiments of coherent plane-wave compounding have been completed by Field II. The simulation experiments of scattering points of plane waves and the simulation experiments of computer cyst phantom of plane waves are completed.