Proceedings Article | 28 January 2009
KEYWORDS: Ultrasonics, Field programmable gate arrays, Imaging systems, Data acquisition, Endoscopy, Ultrasonography, Human-machine interfaces, Control systems, LCDs, Signal processing
Endoscopic ultrasonic imaging system is an important component in the endoscopic ultrasonography system (EUS).
Through the ultrasonic probe, the characteristics of the fault histology features of digestive organs is detected by EUS,
and then received by the reception circuit which making up of amplifying, gain compensation, filtering and A/D
converter circuit, in the form of ultrasonic echo. Endoscopic ultrasonic imaging system is the back-end processing
system of the EUS, with the function of receiving digital ultrasonic echo modulated by the digestive tract wall from the
reception circuit, acquiring and showing the fault histology features in the form of image and characteristic data after
digital signal processing, such as demodulation, etc. Traditional endoscopic ultrasonic imaging systems are mainly based
on image acquisition and processing chips, which connecting to personal computer with USB2.0 circuit, with the faults
of expensive, complicated structure, poor portability, and difficult to popularize. To against the shortcomings above, this
paper presents the methods of digital signal acquisition and processing specially based on embedded technology with the
core hardware structure of ARM and FPGA for substituting the traditional design with USB2.0 and personal computer.
With built-in FIFO and dual-buffer, FPGA implement the ping-pong operation of data storage, simultaneously
transferring the image data into ARM through the EBI bus by DMA function, which is controlled by ARM to carry out
the purpose of high-speed transmission. The ARM system is being chosen to implement the responsibility of image
display every time DMA transmission over and actualizing system control with the drivers and applications running on
the embedded operating system Windows CE, which could provide a stable, safe and reliable running platform for the
embedded device software. Profiting from the excellent graphical user interface (GUI) and good performance of
Windows CE, we can not only clearly show 511×511 pixels ultrasonic echo images through application program, but
also provide a simple and friendly operating interface with mouse and touch screen which is more convenient than the
traditional endoscopic ultrasonic imaging system. Including core and peripheral circuits of FPGA and ARM, power
network circuit and LCD display circuit, we designed the whole embedded system, achieving the desired purpose by
implementing ultrasonic image display properly after the experimental verification, solving the problem of hugeness and
complexity of the traditional endoscopic ultrasonic imaging system.
