Orthogonal sparse dictionary design method based on Chirp code

Abstract

The invention relates to an orthogonal sparse dictionary design method based on a Chirp code, and belongs to the technical field of ultrasonic imaging. The method comprises the steps of S1, adopting aChirp code drive signal processed by a window function in an ultrasonic transmission signal; S2, processing a received ultrasonic echo signal, and describing the same in a matrix form once again; S3,constructing an orthogonal dictionary applied to ultrasonic echo sparse representation through combining with sparse representation of a frequency domain sparse signal; S4, measuring the spare signalby using a measurement matrix, and projecting an original signal from a high-dimensional space to a low-dimensional space; S5, solving an optimal problem via a reconstruction algorithm, thus acquiring a coefficient vector of the original signal; and S6, recovering the original signal by using the coefficient vector, so as to perform ultrasonic imaging. According to the method provided by the invention, the original signal with high precision can be reconstructed under the condition of relatively low sampling rate, and thus the storage space of the ultrasonic system and the implementation complexity of hardware can be reduced.

Description

technical field [0001] The invention belongs to the technical field of ultrasonic imaging, and relates to an orthogonal sparse dictionary design method based on Chirp codes. Background technique [0002] In the process of ultrasonic imaging, a large amount of echo data will be generated, which will bring great troubles to data storage and transmission, and increase the complexity of hardware implementation. In 2006, the compressed sensing theory proposed by Candes and Donoho is just a solution for high-speed data acquisition and large data storage. The theory shows that if the signal itself is sparse or sparse in a transform domain , then the original signal can be accurately recovered from a small amount of sampled data through a reconstruction algorithm. Since compressive sensing first needs to transform the signal to be restored into a certain sparse domain, a common reconstruction algorithm is to first reconstruct the sparse representation coefficients in the sparse dom...

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Problems solved by technology

[0005] In view of this, the object of the present invention is to provide a kind of orthogonal sparse dictionary design method based on Chirp code, this orthogonal sparse dictionary can carry out good sparse representation to ultrasonic signal, effectively overcome traditional sparse dictionary to the insufficient capacity of ultrasonic signal sparseness defects, the original signal can be reconstructed with high precision at a low sampling rate, thus ensuring the quality of ultrasound imaging

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