Key Technologies Of Digital Ultrasound Imaging Optimization Design And Realization

B-mode ultrasonic apparatus is playing a very important role in the modern clinic. And now, research and manufacturing full-digital B-mode ultrasonic apparatus is becoming the inevitable trend. The key to realize full-digital is DSC, which directly determines the parameters of the apparatus. At present, the level of our country has great disparities compared to the international advanced technology in the field of digital medical imaging technology. Therefore, the research of the digital B-mode ultrasonic imaging has great significance.A high reliability and signal noise ratio (SNR) digital B-mode ultrasonic gather card based on FPGA (EP2C35F484C8) was designed in this paper, combined with USB2.0 interface and other circuits. The methods of digital ultrasonic imaging were well researched based on FPGA, focusing on the optimized design and implementation of the key technology of the ultrasonic imaging, such as beam forming, dynamic filter, coordinate transformation and time gain compensation (TGC), and the results of their programs were simulated and verified.In the design of beam forming, the accuracy of delay superposition was improved by refining delay reference clock, the imaging resolution and contrast were improved by segmented dynamic focusing, the side lobe peak was suppressed effectively and the imaging contrast was improved by variable magnitude using window function, and the maximum time delay and the TGC range were decreased, as the same time the focus depth of the near-field was increased by changing the aperture with different focusing depth. During the design of filter, the frequency of the echo signal becomes smaller when the depth of the focus increased, so an effective dynamic filter with changing coefficients was designed and realized by the distributed arithmetic (DA). In the realization of coordinate transformation, the design with better real-time, faster response, higher precision and less source was realized by using dual-clock control of Coordinate Rotation Digital Computer (CORDIC) algorithm and timing output. In the design of TGC, the method of fixed curve compensation on the full-digital B-mode ultrasonic gather card and veriable, controllable compensation on the host computer was designed for TGC, which led to a high gain, easy control and good real-time compensation effect.During the trial period in hospital, the full-digital B-mode ultrasonic apparatus, which is mainly composed by the hardware of full-digital B-mode ultrasonic gather card and the soft system of the digital ultrasonic image, has showed its superiorities, stability, well imaging effect, rich image content. Therefore, the design of the full-digital B-mode ultrasonic gather card in this paper is correct. The optimized methods of the imaging, which were used in this full-digital B-mode ultrasonic apparatus, are efficient.