Design And Implementation Of The Velocity Estimation Module In The Color Flow Imaging System

Color flow imaging(CFI) can display human’s flow velocity magnitude, direction and distribution hemodynamic parameters real time in a wide range. In additional, it has some advantages which are including the organization information, no-damage, no-invision, low ionizing radiation, well real-time and very popular for detecting cardiovascular disease in the clinical.In this paper, the main work is as follows. All works have been done through the platform of field programmable gate array(FPGA) and the software environment of Quartus II. This paper designed and implemented the module o f velocity estimation in the CFI system by Verilog HDL. Firstly, this paper takes full advantage of the signal write-back, serial-parallel combination and pipeline thoughts to complete the demodulation, clutter suppression and the autocorrelation functions. Secondly, according to intensity characteristics and time-domain characteristics, an improved clutter suppression algorithm based on dynamic region partition, the non-stationary clutter rejection method and the polynomial regression method is proposed.What’s more, we simulated this module through Modelsim SE and proved that the logic is correct, reational and reliable. By building a simple analog blood flow device to test the entire system, the list of dissipative resources shown the system had been low dissipative, high integration density and extensible; the clear non-color-encode image indicated the system basically achieved blood flow velocity detection. Simulation results of the new algorithm in Field II toolkit show that the clutter-to-blood ratio after filtering is about 6.120 d B, indicating that this method can better reject the clutter, the estimated blood flow velocity profile maintains the integrity and the achieved blood flow velocity map illustrates higher image quality; in addition, the runni ng time of the algorithm is about 0.3414 s, the execution speed is three times as much as the non-stationary clutter suppression method’s, the real-time characteristic is provided.