A Proposed Warped Choi Williams Time Frequency Distribution Applied to Doppler Blood Flow Measurement

摘要

One of the main goals in ultrasonic Doppler blood flow measurement is the estimation of the mean velocity. The Doppler signal's instantaneous frequency has traditionally been used to estimate the mean velocity. In this work, a non-uniform discrete time frequency distribution is proposed: the warped discrete Choi Williams distribution (WTFD_(CW)). The proposed procedure estimates the instantaneous frequency by concentrating the frequency resolution around the Doppler signal's instantaneous frequency. As a result, a better precision is obtained in the spectral estimation by using a WTFD_(CW) for noisy signals when compared to other methods such as the Discrete Choi Williams Time Frequency Distribution (DTFD_(CW)) with the instantaneous frequency calculated as the centroid of the spectrum.