CN-122017856-A - Low-frequency ultrasonic imaging method, device, computer equipment and storage medium

CN122017856ACN 122017856 ACN122017856 ACN 122017856ACN-122017856-A

Abstract

The invention relates to the technical field of concrete detection, and discloses a low-frequency ultrasonic imaging method, a device, computer equipment and a storage medium; the method comprises the steps of collecting ultrasonic pulse echo signals, carrying out filtering treatment on the collected ultrasonic pulse echo signals, identifying the arrival time of direct waves based on a crest difference mutation criterion, inverting the propagation speed of transverse waves, generating a single-area scanning image by combining a synthetic aperture focusing technology, and finally, carrying out normalization, binarization and connected area decomposition and matching on a plurality of scanning images to realize automatic splicing and fusion of cross-area images and form a two-dimensional ultrasonic imaging diagram covering a long-distance structure. The invention can effectively inhibit noise interference, improve wave velocity inversion and defect identification precision, realize continuous and complete imaging of long-distance concrete structures, and is suitable for internal defect detection of engineering such as submarine tunnels.

Inventors

WEI SHUAISHUAI
ZHANG HUAN
FU JIANCUN
WEI MIN

Assignees

空天信息大学(筹)
山东省交通科学研究院

Dates

Publication Date: 20260512
Application Date: 20260204

Claims (10)

1. A method of low frequency ultrasound imaging comprising: An array transducer is adopted to collect ultrasonic pulse echo signals of a plurality of measuring positions in a single measuring area; Filtering the collected ultrasonic pulse echo signals; Identifying the arrival time of a direct wave in the ultrasonic pulse echo signal after filtering based on a crest difference mutation criterion; inverting to obtain a transverse wave propagation speed according to the arrival time of the direct wave at the measuring position; removing direct wave components from the ultrasonic pulse echo signals subjected to filtering processing based on the arrival time of the direct wave to obtain reflected signals; Imaging the reflected signal using a synthetic aperture focusing technique based on the transverse wave propagation velocity, generating a scanned image corresponding to the measurement region; And splicing the scanning images generated by the plurality of measuring areas to obtain a two-dimensional ultrasonic imaging chart.
2. The method of claim 1, wherein identifying a direct wave arrival time in the filtered ultrasonic pulse-echo signal based on a peak difference abrupt change comprises: performing wave crest detection on the ultrasonic pulse echo signals subjected to filtering treatment, and extracting the amplitude value and the corresponding time of each wave crest to form a wave crest sequence; Calculating the amplitude differences of adjacent peaks in the peak sequence to obtain an amplitude difference sequence; if the peak sequence contains a plurality of peaks, judging the peak time with larger intermediate amplitude corresponding to the maximum value in the amplitude difference sequence as the arrival time of the direct wave; if the wave crest sequence only comprises one wave crest, taking the time corresponding to the wave crest as the arrival time of the direct wave; If no peak is detected, the ultrasonic pulse echo signal is marked as invalid data.
3. The method of claim 1, wherein the inverting yields a shear wave propagation velocity comprising: Collecting the arrival time of the direct waves of all the measuring positions and the positions of the corresponding measuring points; Constructing a mapping relation between the arrival time and the space position; Performing linear fitting on the relation model by a least square method; The inverse of the slope of the fitting result is the transverse wave propagation velocity.
4. The method of claim 1, wherein stitching the scanned images generated by the plurality of measurement regions comprises: carrying out normalization processing on each scanned image; Performing binarization processing on the normalized image, and extracting a region with the reflection intensity higher than a threshold value to obtain a binarized image; decomposing the communication areas of the binarized image, and calculating the barycenter coordinates and the areas of the communication areas; matching the depth similarity and the area similarity of the corresponding communication areas between the adjacent images by comparing; and carrying out space alignment and pixel fusion on the plurality of scanning images according to the matching result.
5. The method of claim 2, wherein said calculating the difference in magnitudes of adjacent peaks in said sequence of peaks comprises: The amplitude difference between adjacent peaks is calculated by the following formula: ; ; Wherein the method comprises the steps of Representing the magnitude of the kth peak, Representing the magnitude of the k +1 peak, For its corresponding amplitude difference.
6. The method of claim 4, wherein decomposing the connected regions of the binarized image, and calculating centroid coordinates and areas of each connected region, comprises: Scanning the binarized image according to the adjacent relation of the pixels; Dividing pixels meeting connectivity conditions into the same connected areas, and assigning unique numbers to each connected area to form an area marking matrix; Determining the total number of pixels contained in each connected region as the area of the region based on the region marking matrix; and calculating the barycenter coordinates of each connected region based on the region marking matrix and the coordinates of each pixel.
7. A low frequency ultrasound imaging apparatus, the apparatus comprising: The signal acquisition module is used for acquiring ultrasonic pulse echo signals; the signal processing module is used for carrying out filtering processing on the signals; the direct wave processing module is used for identifying the arrival time of the direct wave and removing the direct wave component from the filtered signal; the parameter inversion module is used for inverting the transverse wave propagation speed according to the arrival time of the direct wave and the corresponding measurement position; The imaging module is used for generating a scanning image for the reflection signal after the direct wave is removed; And the splicing module is used for splicing the scanning images to obtain a two-dimensional ultrasonic imaging chart.
8. A computer device, comprising: A memory and a processor in communication with each other, the memory having stored therein computer instructions which, upon execution, cause the processor to perform the method of any of claims 1 to 6.
9. A computer readable storage medium having stored thereon computer instructions for causing a computer to perform the method of any one of claims 1 to 6.
10. A computer program product comprising computer instructions for causing a computer to perform the method of any one of claims 1 to 6.

Description

Low-frequency ultrasonic imaging method, device, computer equipment and storage medium Technical Field The invention relates to the technical field of concrete detection, in particular to a low-frequency ultrasonic imaging method, a device, computer equipment and a storage medium. Background In the major concrete engineering such as submarine tunnel, utility tunnel, etc., the pouring quality of secondary lining directly influences structure long-term safety and durability, if can't in time discover inside untight, cavity, crack or hidden defect such as reinforcing bar dislocation in the stage of setting up, these hidden dangers receive water pressure, load and chemical attack effect after the operation period, probably further expand, even cause serious result, cause huge security risk and economic loss. The detection of internal defects of concrete structures mainly depends on ultrasonic technology, however, in complex application scenarios such as tunnel lining, traditional ultrasonic detection faces multiple practical difficulties: Firstly, in the signal preprocessing stage, a common filtering method is easy to cause phase distortion or difficult to effectively extract weak defect signal characteristics in strong noise to influence analysis accuracy, secondly, automatic identification of arrival time of direct waves mostly adopts fixed threshold or simple envelope judgment, adaptability is poor in a complex signal environment of concrete and is easy to be interfered, inversion wave speed is inaccurate, wave speed deviation can directly cause synthetic aperture focusing imaging 'defocusing', resolution is reduced, and finally, imaging results are usually limited to small-range areas, and a plurality of B scanning images (two-dimensional sectional images) of independent areas are spliced into a continuous integral section without an efficient and reliable means, so that the actual requirement of continuous detection of long-distance tunnel lining is difficult to meet. Therefore, a complete ultrasonic detection method which is suitable for severe field conditions and can be extended from high-precision signal processing to continuous panoramic imaging is needed, so that the detection capability and the result reliability of hidden defects in a concrete structure are improved. Disclosure of Invention In view of the above, the invention provides a low-frequency ultrasonic imaging method, a device, computer equipment and a storage medium, which are used for solving the problems that the existing concrete ultrasonic detection method is low in imaging resolution and difficult to realize continuous seamless imaging in a long region due to poor signal quality, inaccurate direct wave identification and wave speed inversion in a strong noise and complex medium environment. In a first aspect, the present invention provides a method of low frequency ultrasound imaging comprising: An array transducer is used for ultrasonic pulse echo signal acquisition at a plurality of measurement positions. The signal acquisition adopts an operating mode of transmitting element by element and receiving element after the transmission, namely when the ith element transmits ultrasonic pulse, the ith+1th to 8 th elements are sequentially used as receiving elements to synchronously acquire echo signals, and the control unit amplifies and analog-digital converts the signals and stores the signals as a time domain signal data matrix. The acquired ultrasonic pulse echo signals are subjected to filtering treatment, and the process adopts a bidirectional zero-phase filtering technology, namely, the original signals are forward filtered, the result time is inverted and then are subjected to secondary filtering, and the secondary filtering result is inverted and then is subjected to time inversion, so that the filtering signals without phase distortion are obtained, out-of-band noise is effectively restrained, and main frequency energy is reserved. Identifying a direct wave arrival time in the filtered signal based on a peak difference discontinuity criterion, comprising: wave crest extraction, namely modeling a filtering signal, detecting and extracting wave crest through local maximum value, and recording amplitude values and corresponding moments to form a wave crest sequence; Peak detection may be formalized as a local maximum point set: ; Wherein the method comprises the steps of Representing the magnitude of the kth peak,For its corresponding time. Calculating the amplitude difference of adjacent wave peaks to form an amplitude difference sequence reflecting the energy change rate; for peak value sequence Constructing adjacent differential sequences: And judging the arrival time, namely taking the time when the peak value corresponding to the maximum value of the amplitude difference is larger than the central amplitude value when the total number of the peaks is more than or equal to 2, directly taking the time of the peak when only 1 pea