Spectrum seeking sub-band minimum variance ultrasonic imaging algorithm fusing alternating multiplier iteration

Abstract

The invention relates to a spectrum seeking sub-band minimum variance ultrasonic imaging algorithm fusing alternating multiplier iteration, and belongs to the technical field of ultrasonic imaging. The algorithm comprises the steps of carrying out delay focusing processing on sampling signals received by array elements to obtain ultrasonic echo data; converting the problem of solving each frequency domain sub-band of an ultrasonic signal into the problem of solving a least square of each time window frequency coefficient of the ultrasonic signal after short-time Fourier transform; introducinga penalty function, and obtaining a maximum posterior probability solution of an improved least square problem step by step in parallel; generating a new frequency domain signal of each array element;obtaining a sample covariance matrix of a frequency domain; calculating a spectrum search sub-band minimum variance beam forming weight fused with alternating multiplier iteration; and processing theobtained weight through inverse fast Fourier transform to obtain a final broadband time domain adaptive beamforming signal. According to the method, the resolution of ultrasonic imaging can be remarkably improved, and the contrast ratio and the robustness to noise can be improved at the same time such that the ultrasonic imaging quality can be improved on the whole.

Description

technical field [0001] The invention belongs to the technical field of ultrasonic imaging, and relates to an ultrasonic imaging algorithm for spectrum seeking sub-band minimum variance combined with alternating multiplier iterations. Background technique [0002] Ultrasound imaging has been widely used in the fields of non-destructive testing and medical diagnosis due to its advantages of safety, real-time, and low cost. The beamforming technology is the key technology of ultrasound imaging, which directly determines the image quality of ultrasound imaging. The traditional Delay and Sum (DAS) algorithm is the simplest beamforming method in ultrasound imaging, with low complexity, good robustness and fast imaging speed. However, it uses a fixed window function weighting that has nothing to do with the ultrasound signal, which leads to an increase in the width of the main lobe, and has inherent defects such as low resolution and severe artifacts. Therefore, some scholars hav...

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Problems solved by technology

[0006] In view of this, the object of the present invention is to provide a spectrum-seeking subband minimum variance ultrasonic imaging algorithm that combines alternating multiplier iterations, which breaks through the resolution limitation caused by the traditional minimum variance narrowband assumption, and solves the subband minimum variance frequency domain beam The resulting spectrum leakage problem improves the imaging resolution and contrast of the algorithm, and at the same time improves the robustness of the algorithm to noise, thereby comprehensively improving the quality of ultrasound imaging

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