A new adaptive imaging technique using optimal aperture size [biomedical ultrasound imaging]

Focusing errors caused by sound-velocity inhomogeneities in human tissue, also known as phase aberrations, reduce coherence of the received signals. Low coherence results in high sidelobes in the radiation pattern and degrades contrast resolution. This paper proposes an efficient adaptive imaging technique using optimal receive aperture size. The technique determines the optimal aperture size based on the coherence factor, which quantifies coherence of the received array signals and a threshold can be set to distinguish a mainlobe signal from sidelobes. With the thresholding, the receive aperture size at each imaging position can be optimally determined so as to enhance the mainlobe signal and suppress the sidelobes. Thus, focusing errors can be reduced. The efficacy of the proposed technique was demonstrated by experimental array data. This technique effectively reduces sidelobes and decreases speckle variance. The characteristics of the proposed technique are also explored.