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A simulation study on the performance of different estimators for two-dimensional velocity estimation

Techniques have been described in the literature to enable two-dimensional strain rate estimation. They are based on two-dimensional velocity estimation. One of the problems to obtain robust lateral strain rate estimates is the fact that lateral velocity estimates are intrinsically noisier than axial ones. The aim of this study was to find the optimal estimator for tracking of the radio frequency patterns both axially and laterally. Theoretical properties for the following estimators were investigated using simulations: cross correlation, normalized cross correlation, sum of absolute differences and sum of squared differences. Two-dimensional velocity estimation was not feasible using cross correlation. However, normalized cross correlation, sum of absolute differences and sum of squared differences showed accurate axial and lateral results.