Weighted broadband time reversal operator resolution acoustic imaging method

Abstract

A weighted broadband time reversal operator resolution acoustic imaging method includes the steps of conducting fast Fourier transform on a signal received through a receiving and transmitting combined array, dividing the signal into multiple sub-bands through a narrow-band filter, resolving the time reversal operator singular value corresponding to each sub-band, relating the feature vector corresponding to the maximum feature value to the transmitting vector based on an acoustic propagation model so as to obtain an ambiguity function, extracting the maximum value of the ambiguity function of each sub-band and the two-dimensional sound field space corresponding to the sub-hand, designing a weighting coefficient according to the maximum feature value, weighting the ambiguity functions, and representing a three-dimensional image after accumulating the results of all the sub-bands in a coherent mode. The method has the advantages that the scattering properties of targets are applied to the broadband time reversal operator resolution imaging method in a weighted mode, broadband information is fully used, the spatial features of expansibility targets are truly displayed, and the effectiveness and the reliability of the scheme are verified through experiments.

Description

Technical field [0001] The invention belongs to the field of acoustic detection for the development and utilization of marine resources, and specifically is a method for acoustic imaging of point targets and expandable targets by using an array. Background technique [0002] Since sound waves propagate in water better than light waves and electromagnetic waves, the detection of marine resources is basically based on acoustic methods. At present, the space processing technology actually used in sonar systems is still the plane wave beamforming that emerged and developed in the 1950s and 1960s under the background of white noise and free-field propagation. However, in the shallow sea environment, the traditional processing method based on the plane wave model is no longer applicable. Because the propagation of acoustic signals in the ocean presents a multi-path / multi-normal mode state, it is easy to cause false targets or ghosting phenomena in the detection process. The detection ...

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Problems solved by technology

[0003] However, the current inverse operator decomposition method is that each frequency point corresponds to a target scattering matrix, and each frequency band is processed separately, which has the following disadvantages: (1) The processing of broadband signals usually only considers the center frequency or the entire frequency band As a result, the non-coherent accumulation method does not effectively use the information of the broadband signal; (2) Especially for the extended target in the waveguide environment, due to the scattering characteristics of the target itself, the waveguide propagation effect, and the relationship between the transducer and the frequency, etc. The impact of the final target scattering characteristics is a function of frequency, but the current processing process does not take into account and utilize this scattering characteristics

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