An ultrasound imaging system includes a transducer array, with an array of transducer elements that transmits an ultrasound signal and receives a set of echoes generated in response to the ultrasound signal traversing a flowing structure. The ultrasound imaging system further includes a beamformer that beamforms the set of echoes, generating a beamformed signal. The ultrasound imaging system further includes a pre-processor that performs basebanding, averaging and decimation of the beamformed signal and determines an autocorrelation of the basebanded, averaged and decimated beamformed signal. The ultrasound imaging system further includes a velocity processor that generates an axial velocity component signal and a lateral velocity component signal based on the autocorrelation. The axial and lateral velocity components indicate a direction and a speed of the flowing structure in the field of view.
