Echo signal separation method for ultrasonic flaw detection

Abstract

The invention discloses an echo signal separation method for ultrasonic flaw detection. The method comprises steps of: first, acquisition and synchronous uploading of an ultrasonic echo signal: an ultrasonic flaw detection device performs ultrasonic detection on a tested object, acquires an ultrasonic echo signal F(t) of the tested object, and synchronously transfers the acquired ultrasonic echo signal F(t) to a data processing device ,wherein the ultrasonic echo signal F(t) comprises ultrasonic echo signals of positions of K flaws of the tested object; second, signal sparse and decomposition;and third, echo signal separation: the data processing device separates the ultrasonic echo signal F(t) according to K optimal matched atoms in an iteration decomposition optimal atom set, and acquires K separation signals. The method has simple steps, is reasonable in design, is easy to realize, has good use effect, and conveniently, rapidly separates overlaid signals in multiple flaw positionsin the same ultrasonic echo signal through signal sparse decomposition.

Description

technical field [0001] The invention belongs to the technical field of ultrasonic flaw detection, in particular to an echo signal separation method for ultrasonic flaw detection. Background technique [0002] Ultrasonic flaw detection (also known as ultrasonic testing or ultrasonic testing) is a non-destructive testing method that uses the difference in acoustic properties of materials and their defects to reflect the reflection of ultrasonic wave propagation and the energy change of penetration time to test the internal defects of materials. The principle of ultrasonic flaw detection is that the transmission loss of ultrasonic waves in solids is very small, and the detection depth is large. Since ultrasonic waves will reflect and refract on heterogeneous interfaces, especially if they cannot pass through gas-solid interfaces, if there are pores, cracks, Defects such as delamination (gas in the defect) or inclusions, when the ultrasonic wave (also called ultrasonic signal or...

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Problems solved by technology

[0008] In addition, when using the sparse decomposition method for signal denoising (also called signal extraction), the essence is to use the matching pursuit algorithm for signal extraction. Because in the matching pursuit algorithm, firstly, the selection of Gabor atoms has no physical meaning, and secondly, if If a wrong Gabor atom is selected in a certain iteration, the subsequent iteration process has to correct this error, resulting in mistracking and poor algorithm performance.

Moreover, according to the sparse signal representation theory, when the size of dictionary atoms is smaller than a threshold, due to the cumulative consistency constraints, the sparse representation is unstable and unreliable

Therefore, the existing sparse decomposition methods have many defects

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