Abstract: Synthetic aperture ultrasound imaging is often used in modern digital medical ultrasound imaging for its high-resolution and high-contrast images with a small number of transducers. But the traditional synthetic aperture method is very complex and limited in real-time imaging. Contrast to the non-uniformly sampling data imaging from customized target area, a beam-forming algorithm of the uniformly sampling system applied to a multi-element synthetic aperture ultrasound imaging system using a high speed digital circuit was designed and implemented in a hardware circuit based on field programmable gate array(FPGA).The system was composed of one FPGA EP2C8Q208C8 of Cyclone Ⅱ series from Altera corporation and one synchronous dynamic random access memory (SDRAM) chip to store echo data, which were delay superimposed and weighted and sent to PC via USB. With the pipeline architecture and the parallel nature of FPGA, the beam-forming algorithm was implemented. The test results demonstrate that the system is accurate and effective and can be applied to real-time ultrasound imaging.

Key words: ultrasound imaging, beam-former, delay superimpose, field programmable gate array (FPGA)