A sonar target enhancement method based on a new image operator

Abstract

The invention discloses a sonar target enhancement method of a new image operator, which solves the problem of target trajectory enhancement of a passive sonar azimuth history map. The invention provides a new image detection operator, which detects and processes the multi-frame data after beamforming, thereby realizing the reduction of background noise, the suppression of lateral lines and the extraction of target trajectory edges. Adaptive segmented equalization of the detected row data increases the local data contrast, increases the contrast between the target and background, obtains a larger processing gain, significantly enhances the target, and the azimuth history map is clear. The invention does not need to set any parameters, has good compatibility, small calculation amount, simple programming realization and the like, and can be used for the processing of the dynamic history diagram and the static two-dimensional image, and has wide application range.

Description

technical field [0001] The invention belongs to the field of sonar signal and information processing, and mainly relates to a sonar target enhancement method of a new image operator. Background technique [0002] Passive sonar does not emit sound waves. It uses the noise emitted by the target ship and the signal emitted by the active sonar installed on the target ship to detect the target. Usually, the time and azimuth history map is used to detect and track the target trajectory. Due to the noise caused by the ocean environment And other disturbances, so that the target trajectory is not obvious or not displayed at all, affecting the correct detection and tracking of the target. [0003] At present, it is generally dealt with from the perspective of time or space. From the spatial aspect, there are mainly numerous beamforming and background equalization methods. Due to the space-time non-stationarity of the underwater acoustic channel, complex multi-path and reverberation...

AI Technical Summary

Problems solved by technology

Due to the space-time non-stationarity of the underwater acoustic channel, complex multi-path and reverberation signals, conventional beamforming is difficult to distinguish signal and noise subspaces at low SNR when the array shape and array aperture are fixed. Prone to false peaks, poor reliability in actual offshore applications

The MVDR algorithm can obtain higher resolution and noise interference suppression performance by imposing no distortion constraints on the output signal to the array pointing direction, but it needs to be loaded diagonally. Usually, there is no good way to determine the amount of diagonal loading. If the amount of loading is too large, it will Reduce array gain, etc.

Some of these algorithms and their improved methods have unsatisfactory performance, and some have high constraints.

Although some algorithms in the background equalization and improved algorithms can improve the overall visual performance of the azimuth history map and remove large-scale fluctuations, they need to manually set the parameters. Once the parameters are not set properly, the processing effect of the algorithm will be greatly affected, and the algorithm will be increased. Difficulty in practical application, no enhanced effect on the target

In terms of time, it is commonly used to increase the length of signal accumulation time in the algorithm processing process before processing, but in addition to increasing the amount of calculation, the accumulation gain of noise cannot be ignored in the accumulation process under low signal-to-noise ratio.

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