多普勒彩色血流成像中流速估计方法的研究

目的：探讨多普勒彩色血流成像中流速估计的方法。方法：对多普勒彩色血流成像中流速估计的两种算法-相域自相关和时域互相关进行了理论分析，在FieldII软件平台上对两种算法进行仿真。分别在中心流速为0．5m／s（中低速）和0．5m／s（高速）时进行血流速度仿真，得出了各自不同中心流速的血流速度分布曲线，并对其进行了对比分析。结果：相域自相关方法对中低速血流进行流速传计的精确度和稳健性都强于时域互相关方法；对于高速血流相域方法估计结果产生了混叠，但时域方法可以通过加大最值的搜索范围仍然能够得到正确的估计结果。结论：两种方法各有优缺点，互为补充。在实际应用中可以考虑结合使用两种方法，充分利用二者的优点。

The Study of Flow Velocity Estimation in Ultrasonic Medical Color Flow Mapping System

Objective： To explore the flow velocity estimation in ultrasonic medical Color flow mapping system. Methods： The theory of autocorrelation and crosscorrelation algorithms for color flow mapping was analyzed, and the two algorithms were simulated in Field II software enviroment. Respectively when the central speed of flow is 0.5m/s （low speed） and 0.5m/s （high speed） carries on the blood stream speed simulation. Then we get the flow velocity curve for each algorithm in different core flow velocity, and compare them. Results： Phase domain auto-correlation method for low blood flow velocity estimation are stronger than time-domain cross-correlation method in accuracy and stability; For high-speed blood flow phase-domain method resulted in aliasing, but the time-domain method can increase the value of the scope of the search will still be able to obtain accurate estimates. Conclusion： The two methods have their own advantages and disadvantages,and complement each other. In practice, we can consider a combination of two methods to fully utilize the advantages of both.