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Method and apparatus for random array beamforming

  • US 4,559,605 A
  • Filed: 09/16/1983
  • Issued: 12/17/1985
  • Est. Priority Date: 09/16/1983
  • Status: Expired due to Fees
First Claim
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1. Beamforming apparatus comprising:

  • (a) a plurality of transducers randomly distributed for receiving radiant energy, said transducers generating analog output signals indicative of the received radiant energy,(b) means for converting said analog transducer output signals at a predetermined sampling rate into digital signals,(c) means for storing a group of said digital signals for each transducer,(d) means for performing a discrete Fourier transformation of each group of digital signals to obtain Fourier frequency coefficients F.sub.ω

    (k) where ω

    identifies the frequency and k is an integer having values 1,2 . . . N identifying the transducer, N being the total number of distributed transducers,(e) means for spatially convolving said coefficients F.sub.ω

    (k) of equal ω

    to obtain a set of coefficients G.sub.ω

    "(D) where D is the spacing between pairs of transducers,(f) means for generating additional values of G.sub.ω

    "(D) by interpolation to obtain a substantially continuous function I107 "(D),(g) means for performing a spatial Fourier transformation of I107 "(D) to obtain a transform function T.sub.∫

    (F) where F is a parameter representing the different spatial frequencies in I107 "(D)(h) means for averaging a plurality of values of at least one of G.sub.ω

    "(D), I.sub.ω

    "(D) and T.sub.ω

    (F) from a plurality of said output signal groups, and(i) means, responsive to the averaged or average-derived value of T.sub.ω

    (F) for generating an output representative of the far field power of said radiant energy as a function of angle.

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