A new blood velocity estimator for suppressing frequency aliasing in color flow imaging

Blood flow velocity estimation is a critical technique in ultrasound color flow imaging. Existent flow velocity estimation methods include autocorrelation, cross-correlation and butterfly search technique. Among these estimators, autocorrelation estimator is the most commonly used technique in current medical ultrasound systems, due to its low computational complexity. But it's intrinsically a frequency domain estimator, and is limited by the sample theorem. While measuring high speed blood flow, frequency aliasing will occur, because the Doppler frequency shift exceeds the Nyquist limit. To solve this aliasing problem, a new blood velocity estimator is proposed, which incorporates the autocorrelation technique with the butterfly search method. Simulation results show that the frequency aliasing artifact can be eliminated without adding too much computational complexity.