Frequency domain passive cavitation imaging and frequency compound imaging method based on feature space adaptive beamforming

Abstract

The invention provides a frequency domain passive cavitation imaging and frequency compound imaging method based on feature space adaptive beamforming, including the steps: performing Fourier transform on a time domain cavitation signal and performs phase shift and array element apodization processing; constructing a covariance matrix and obtaining the weighting vector of adaptive beamforming according to the normalized steering vector and covariance matrix; decomposing the covariance matrix into the feature space, and projecting the weighted vector onto the signal subspace and then carrying out passive cavitation imaging in the whole frequency domain; constructing a cavitation artifact ratio index and selecting the optimal steering vector uncertain set parameters according to the resultsof passive cavitation imaging in full frequency domain under different steering vector uncertain set parameters, so as to realize passive cavitation imaging and frequency composite imaging in different sub-frequency domains. The invention can greatly suppress imaging artifacts, thereby improving spatial resolution of passive cavitation imaging in frequency domain, can carry out comprehensive characterization on any plurality of frequency components, and is suitable for real-time monitoring of multiple focused ultrasonic therapy applications.

Description

Technical field [0001] The invention belongs to the technical field of ultrasonic detection and ultrasonic imaging, and specifically relates to a frequency domain passive cavitation imaging and frequency composite imaging method based on characteristic space adaptive beam synthesis. Background technique [0002] In the field of biomedical ultrasound, ultrasound cavitation has always been a research hotspot, and it plays a vital role in focused ultrasound therapy such as tumor thermal ablation, extracorporeal lithotripsy, ultrasound thrombolysis, and drug release. In tumor thermal ablation, cavitation microbubbles will block the focused ultrasound beam and affect the focusing performance, resulting in unpredictable damage area and reducing the accuracy of treatment; on the other hand, cavitation can increase the efficiency of the acoustic-to-thermal conversion of the tissue, thereby Reduce treatment energy and shorten treatment time. In the crushed stone, physical phenomena such ...

AI Technical Summary

Problems solved by technology

However, the traditional frequency-domain passive cavitation imaging method is essentially a blind beamforming method that does not depend on the characteristics of the data itself, which will cause extremely serious imaging artifacts and poor imaging quality, and cannot improve the accuracy of cavitation spatial positioning. Accuracy, so it is not conducive to real-time monitoring of focused ultrasound treatment process

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