Design And Realization Of Color Doppler Ultrasound Signal Process System Based On DSP Array And Gigabit Ethernet Interface

Ultrasonic diagnosis as a cost-effective, non-intrusive, rapid diagnostic method has seen wide applications in clinical medicine. High-end color Doppler ultrasound scanners combine multiple functions like B-mode, M-mode, pulsed Doppler and color Doppler blood flow to provide an intuitive and rapid imaging of blood flow and motion in addition to the traditional 2-D structural image for better diagnosis. The all-digital, compact and portable color Doppler ultrasound scanners have attracted much attention of the industry in recent years in that they play a significant role in boosting healthcare in the remote and underdeveloped regions of China.This paper presents a design of a signal process and image transmission subsystem based on DSP array and gigabit Ethernet interface for the color Doppler ultrasound scanner. The color Doppler ultrasound system is a signal process intensive system whereas the DSP array achieves high performance through a coordinated array of DSP chips to process that vast amount of data. The low-cost, high-performance gigabit Ethernet is a mature technology that has been widely deployed. Both techniques have laid a firm foundation for building low-cost portable ultrasonic scanners of various scales.The paper begins with a brief review of the principles of ultrasonic imaging, then elaborates by the process flow of the ultrasonic scanner the basic signal processing algorithms, including digital beam forming, digital envelope detection, B-mode and M-mode imaging, PW-mode imaging and CF-mode imaging, before delving into the two key techniques of the portable ultrasonic scanner– DSP array interconnection and gigabit Ethernet.The design of the system is centered on the TigerSHARC TS201 processor and the AX88180 gigabit Ethernet controller. The design uses point-to-point interconnection and distributed storage to achieve modularity and scalability. A logic implemented high-speed interface between the link ports of the TS201 processors and the front-end FPGA provides sustained throughput of 100MB/s. The design also implements an interface between the TS201 processor and the AX88180 Ethernet controller at the rear end, complete with low level device drivers for the Ethernet controller. Data is transmitted in real time through low-level MAC frames to provide a 65MB/s real-time image data transmission rate between the scanner and the PC, thereby overcomes the issue of latency uncertainties of TCP/IP transmissions. The subsystem comes with a signal processing program that realizes the B-mode and CF-mode imaging and verifies that the requirements of a color Doppler ultrasound scanner are met.