Optimum beamforming for sidelobe reduction in ultrasound imaging

A constrained adaptive beamforming in a deterministic sense is considered for side lobe reduction, leading to an adaptive weighting of the uniform delay-and-sum beamformer; based upon this, the coherence factor and other similar methods are interpreted as beamforming methods. A generalized form of the weighting factor for the side lobe reduction is also established. It is shown through simulations that restricting the apodization vector to a parametric representation through a discrete Fourier transform or discrete cosine transform can result in higher quality images with fewer artifacts and enhanced contrast properties compared with images obtained through the coherence factor-like methods.