A speckle suppression technique based on beam-space processing for medical ultrasound imaging

In the spatial frequency domain, a speckle suppression technique is proposed to reduce ultrasound speckle noise. The beam space is traced by using consecutive subapertures with very small angular diversity. The full array is synthesized by using two different types of subaperture. The element number of the second subaperture type is half of the first one. The number of A-scans is chosen according to the spatial Nyquist criterion of each subaperture. The small number of acquired beams is increased to the required beam number of the full synthesized array by using bilinear interpolation. Since beamforming is performed over two different numbers of beam lines the imaging space is divided into small angular diversity after the interpolation process. Finally the sub-images obtained from each subaperture are added coherently to form the speckle reduced final image.