Analysis of velocity estimation error for a multidimensional Doppler ultrasound system

The error characteristics of a single-transducer (one dimensional), dual-transducer (two-dimensional), and triple-transducer (three-dimensional) system for velocity estimation are examined. A velocity vector is completely characterized by the magnitude and the directional angles. For a single-transducer case, the velocity magnitude alone can be estimated. The variation in the directional angles for a single-transducer case cannot be accounted for in the estimation process, thus resulting in large errors. For a dual transducer, both the velocity magnitude and the angle on the x-y plane can be estimated. The use of an extra transducer provides added flexibility in the estimation process. Variation in one of the directional angles is accounted for in the estimation process, thus resulting in smaller error than the single-transducer case. For a triple-transducer case, if the normal angles between the three transducer axes are known, then the complete velocity vector with all the directional angles can be estimated.