1.A new MTI scheme in ultrasonic color flow mapping systems.
Naizhang FENG ; Jianqiu ZHANG ; Yi SHEN
Journal of Biomedical Engineering 2006;23(2):413-418
In color flow imaging systems, the ultrasound Doppler signal scattered from blood is heavily corrupted by the strong clutter signal reflected from the slow-moving muscular tissue. Moving target indicator (MTI) is a key technique of rejecting the clutter signal and detecting blood flow. To improve the performance of detecting blood flow, a new MTI scheme is proposed in this paper. It consists of a pre-filter, a clutter weak-rejector and a 2-order AR estimator. After the processing of pre-filtering and clutter weak-rejection, the strong clutter signal is effectively eliminated and its strength is comparable with blood flow. Under such condition, the optimal performance can be attained by the 2-order AR estimator. It is illustrated in the simulation that, compared with the data from traditional methods, the blood flow parameters are estimated with smaller deviation and the lower speed flow is detected.
Blood Flow Velocity
;
Equipment Design
;
Humans
;
Image Interpretation, Computer-Assisted
;
instrumentation
;
methods
;
Ultrasonography, Doppler, Color
;
instrumentation
;
methods
2.Study on the method of testing the wall filter performance.
Naizhang FENG ; Jianqiu ZHANG ; Yi SHEN
Journal of Biomedical Engineering 2006;23(1):196-199
In order to test the performance of wall filters, we propose a method for simulation of Hybrid Doppler testing signal, which adopts a rectangular power spectrum. In the method, the parameters of clutter, blood flow and system noise can be adjusted with flexibility. The problem about choosing model parameters is discussed as an emphasis. Several reasonable and typical parameter combination patterns are presented. Furthermore, an example is given to explain the process of choosing the parameters and testing the wall filter performance.
Blood Flow Velocity
;
physiology
;
Computer Simulation
;
Humans
;
Rheology
;
instrumentation
;
methods
;
Signal Processing, Computer-Assisted
;
Ultrasonography, Doppler, Color
;
instrumentation
;
methods