A multi-beam emission three-dimensional imaging method

Abstract

The invention provides a multi-beam transmission three-dimensional imaging method. A transmitting array and a receiving array are uniform linear arrays intersecting with each other perpendicularly. A transmitted signal is formed by overlaying a plurality of independent sub-pulses on the time domain, and transmission weighting is carried out on each sub-pulse before transmission, so that the sub-pulses point to corresponding strips respectively. Each transmission array element of the transmitting array transmits the same sub-pulses at the same moment. The receiving array collects echoes of each strip. A copy of each sub-pulse is used for carrying out matched filtering on the echoes on the receiving array, beam forming is carried out after the echo components corresponding to each sub-pulse are separated, and then a three-dimensional image of each strip can be obtained. The three-dimensional images of all the strips are spliced to obtain the three-dimensional image of a whole target area. According to the multi-beam transmission three-dimensional imaging method, the work efficiency is much higher than that of a traditional crossed-shaped array imaging system, and use of complicated quadrature coding signals is avoided.

Description

technical field [0001] The invention relates to an array imaging method. Background technique [0002] A three-dimensional imaging system usually uses an array such as a rectangular planar array to collect and process echoes (Murino V and Trucco A, Three-dimensional image generation and processing in underwater acoustic vision, in Proc. IEEE, 2000; 88(12): 1903-1948.). However, the use of a planar array will bring about the disadvantage of a large number of array elements, resulting in an extremely high cost of the 3D imaging system. In order to save the cost of array elements, a cross array composed of two mutually perpendicular linear arrays can be used for three-dimensional imaging (de Jong CD, Lachapelle G, Skone S. Multibeam sonartheory of operation. Delft: Delft University Press, 2002.). The cross array can obtain three-dimensional imaging capabilities similar to the rectangular planar array through its own movement, and can also perform three-dimensional imaging thro...

AI Technical Summary

Problems solved by technology

In order to suppress cross-correlation interference and auto-correlation sidelobe interference, these coded signals need to use a large number of subcodes to synthesize long pulse signals, which brings a large computational burden to the matched filter processing at the receiving end.

In addition, the waveforms of these quadrature-coded signals are too complex, and their robustness in harsh environments is not as good as traditional simple waveforms, such as continuous wave (CW: Continuous Wave) pulses and linear frequency modulation (LFM: Linear Frequency Modulation) pulses

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