Modified autocorrelation method compared with maximum entropy method and RF cross correlation method as mean frequency estimator for Doppler ultrasound

The modified autocorrelation method (MAC) incorporating two-dimensional temporal and spatial averaging for mean frequency estimation in ultrasound color/flow mapping is evaluated. The equivalence among the MA, the classic autocorrelation method (AC) and the RF cross-correlation method has been investigated. Recently, the maximum entropy method (MEM) has been applied to the ultrasound color flow imaging. The performance of the MA, AC, and the MEM methods is examined using computer simulations. Simulation results show that the MA method performs best in all of the cases especially for short and highly noisy signals. The MEM performs similarly with that of the original AC method in most cases but shows more accurate results than the AC method for short and extremely noisy signals