Adaptive estimation of the mean frequency of a Doppler signal from short data windows.

The color Doppler estimator (CE1), which is calculated from the phase of the first correlation lag of the Doppler signal, is compared to the general mean frequency estimator (CEn), which is based on a weighted summation of all the available correlation lags, for long and short Doppler data sets (typically 48 and 8 Doppler samples). A new estimator of the Doppler signal mean frequency is derived from the results of this study. It optimizes the compromise between the range of analyzable frequencies and the estimation variance for the characteristics of the Doppler signal. Demonstration is provided that the behavior of this estimator shifts from that of CE1 to that of CEn, according to the setting of a single parameter. An adaptive version of this estimator is implemented and applied to Doppler recordings. Applications can be contemplated for color Doppler imaging.