Abstract
This article describes the general theory of the classical Doppler technique for flow mapping and show that its main assumptions do not generally hold for ultrasound imaging. It then develops a generalized model for frequency-domain flow mapping in practical ultrasound imaging situations. Using this model, it is shown that it is possible to compute the true velocity from single-aperture configurations. In addition, improving the resolution and velocity estimation accuracies is discussed and a novel approach is proposed based on a generalization of the radar-ambiguity function model. Also consider are the same problems for time-domain techniques. Further, a generalization of the correlation technique that takes into account the ultrasound field effect, is proposed and it is shown that it is theoretically possible to obtain true-velocity flow maps from single-aperture configurations. Finally, the relative advantages and disadvantages of both frequency-domain and time-domain techniques are discussed.