An arrangement of transmitter and receiver arrays for synthesizing acoustical holograms

Abstract

AbstractA method is discussed for synthesizing acoustic holograms consisting of MN pieces of data with M transmitters and N receivers in an acoustic hologram imaging system. Several methods similar to the approach presented here for reducing the total number of transmitters and receivers are examined. the distinctive feature of the proposed method lies in the arrangement of transmitter and receiver arrays on separate planes. the point‐spread function of the synthesized holographic imaging system is computed and the arrangement of transmitter and receiver arrays is restricted so that the grating lobe providing narrower separation is eliminated. the arrangement obtained is a generalization of the well‐known multibeam method in that the transmitter and receiver surfaces are separated. Hence it is applicable not only to reflection holograms but also to transmission holograms. It is also shown that under these conditions the numerical image reconstructed from a hologram can be realized by a single application of the discrete Fourier transform of the MN data. Finally, the results of experimental and numerical simulations are shown and the validity of the proposed method is confirmed.