in a digital ultrasound imaging system , artifacts due to spurious ultrasound reflections from a highly reflective object outside the region of interest are reduced in magnitude by apparatus included in the beamforming system of the digital imaging system . a null is formed in a specified direction in the ultrasound beam patterns by perturbing the time delay on each receive channel . after estimating the direction of the highly reflective , interfering object and computing a time delay perturbation using a very fast algorithm , a null approximately 10 db deep is introduced into each beam in the direction of the interfering object . this null reduces the magnitude of artifacts in the image , thereby providing image enhancement .