Method and system for enhancing ultrasonic guided wave signal based on multi-modal recognition and fusion

A system for enhancing an ultrasonic guided wave signal based on multi-modal recognition and fusion, comprising:

• an ultrasonic guided wave excitation probe and an ultrasonic guided wave receiving probe, configured to excite and receive an ultrasonic guided wave signal respectively;
• an excitation module, generating and amplifying an excitation signal and generating an ultrasonic guided wave propagation signal within a detected structure through the ultrasonic guided wave excitation probe;
• a collection-synchronous transmission module, collecting a detection signal through the ultrasonic guided wave receiving probe and synchronously transmitting the detection signal to a data processing platform;
• a detection control module, configured to control the excitation module and the collection-synchronous transmission module;
• and
• the data processing platform, comprising a frequency dispersion dictionary database generation module and a fusion and enhancement processing module of a multi-modal ultrasonic guided wave signal, wherein
• the frequency dispersion dictionary database generation module is configured to calculate a frequency dispersion curve of the detected structure, obtain dispersion signals of a modal number, a wave number, and a group velocity, and calculate, as an atomic signal, a signal of an ultrasonic guided wave excitation signal that propagates in a detected object through a target detection mode, and construct an ultrasonic guided wave frequency dispersion dictionary;
• the fusion and enhancement processing module of a multi-modal ultrasonic guided wave signal comprises a mode separation and recognition unit of an ultrasonic guided wave signal, a single modal sub-signal determining unit, a main mode conversion sub-signal determining unit, an interference signal removing unit, and a sub-signal resampling and half-wave envelope signal extraction unit, and an enhanced signal calculating unit for a target signal source;
• the mode separation and recognition unit of an ultrasonic guided wave signal uses the ultrasonic guided wave frequency dispersion dictionary to perform modal signal separation and recognition on the ultrasonic guided wave signal, to obtain a series of sub-signals;
• the single modal sub-signal determining unit performs first signal source distance conversion, and determines different modal sub-signals with a same or similar signal source distance as single modal sub-signals based on a modal recognition result and modal group velocity of the sub-signals, and divides the different modal sub-signals with a same or similar signal source distance into a same signal source target group;
• the main mode conversion sub-signal determining unit performs second signal source distance conversion and assumes that the potential mode conversion sub-signal is a modal conversion signal of a main modal signal at a signal source based on the signal source distance and modal group velocity of the signal source target group, and determines, as a main mode conversion sub-signal, a potential mode conversion signal with a signal source distance the same as or similar to a source signal distance of the signal source target group;
• and
• the enhanced signal calculating unit for the target signal source is configured to superpose half-wave envelope signals of the resampled sub-signals in a same signal source target group, to obtain an enhanced signal of the target signal source.