Identification and impact of blocked elements in 1-D and 2-D arrays

In an attempt to characterize the signals on the blocked elements and to assess the image degradation they cause we collected the individual-channel signals from a clinical matrix array on a phantom through a layer of absorbing rubber and on the human liver intercostally. The signal amplitude and nearest-neighbor normalized cross-correlation exhibited significantly lower values for the blocked elements than for the remaining elements on the aperture. The channel-signals were summed coherently in the elevation dimension to create a synthetic receive 1-D aperture data-set. B-mode images of liver vasculature that were created for a growing synthetic 1-D aperture indicate that beamforming with the blocked elements turned off can reduce noise and improve visibility of targets.