Multi-frequency emission beam formation method and application

Abstract

The invention discloses a multi-frequency emission beam formation method. The method includes: (1) the beam direction of an emission array of a crossed array is divided into a plurality of sectors, a series of sector sonar beam signals of different frequencies are emitted in sequence in each sector, and the sector sonar beam signals with each frequency point to a beam direction in the corresponding sector; and (2) after the sector sonar beam signals with all the frequencies in each sector are emitted, sonar echo signals are received by employing a reception array in the crossed array, frequency information corresponding to all the sector sonar beam signals in each sector is extracted via discrete Fourier transform, beam formation calculation is performed in frequency domains corresponding to the frequency information, and a beam intensity result is obtained. According to the method, the emission time of the crossed array can be reduced, the beam performance similar to a two-dimensional plane reception array is obtained, and the complexity of an underwater real-time three-dimensional acoustic imaging system is reduced. The invention also discloses the application of the method in the reconstruction of three-dimensional acoustic images.

Description

technical field [0001] The invention relates to the field of three-dimensional acoustic imaging, in particular to a multi-frequency transmit beam forming method and application. Background technique [0002] Underwater real-time three-dimensional acoustic imaging technology is a new type of underwater detection technology that has received widespread attention in recent years. It has broad application prospects in many fields. [0003] Currently, there are three main three-dimensional acoustic imaging methods: focused acoustic imaging / acoustic lens focused imaging, beamforming acoustic imaging, and holographic acoustic imaging. Among them, the digital beamforming technology has the advantages of flexibility and high efficiency, so it is more and more widely used in the acoustic imaging system. [0004] In an underwater real-time 3D acoustic imaging system, in order to obtain 3D information of the scene, a 2D planar transducer array is usually required to receive sonar echo...

AI Technical Summary

Problems solved by technology

Aiming at the huge hardware overhead and computational load of the underwater 3D acoustic imaging system, as well as the insufficient real-time performance of the cross-shaped array, this method takes reducing the number of shots of the cross-shaped array as the starting point, and effectively reduces the number of shots of the cross-shaped array from the vertical beam The number of directions is reduced to the number of divided sectors, which greatly shortens the time required to construct a frame of three-dimensional acoustic images, solves the problem of insufficient real-time performance of the cross-shaped array to a certain extent, and can obtain a DM algorithm similar to that of a two-dimensional plane receiving array Similar beam performance indicators (main lobe width, side lobe peak value), while greatly reducing calculation requirements

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