Physical factors affecting the performance of two-dimensional vector flow imaging

A two-dimensional correlation technique is capable of measuring target velocities in any direction in the imaging plane. The inaccuracy in the measurements is related to system parameters such as signal-to-noise ratios, correlation coefficients, and spatial frequencies, and it is shown how factors such as pulse bandwidth, stationary noise, and focal errors can introduce errors in the measurements. The effect of the anisotropic nature of speckle in the axial and lateral dimensions on the magnitude of errors in the two dimensions is discussed