A method and system for dry casing defect detection based on ultrasonic phased array

Abstract

The present application relates to the technical field of ultrasonic defect detection, and particularly relates to a dry casing defect detection method and system based on an ultrasonic phased array, which comprises the following steps: obtaining the sound path between each pixel point in single plane wave imaging corresponding to each deflection angle and each transmitting array element and each receiving array element, obtaining the total flight time of each pixel point in single plane wave imaging to each transmitting array element and each receiving array element according to the sound path and the focusing delay of each transmitting array element; obtaining the superimposed signal intensity of each pixel point in single plane wave imaging corresponding to each deflection angle according to the total flight time and full matrix data, and obtaining a weighted composite image through weighting; performing post-processing and segmentation on the weighted composite image to obtain a plurality of new connected domains; and screening a bubble defect connected domain from all new connected domains through the area of the new connected domain. The present application improves the accuracy of dry casing defect detection.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic defect detection technology, and in particular to a method and system for detecting defects in dry sleeves based on an ultrasonic phased array. Background Technology

[0002] Dry bushings are widely used in the power industry due to their excellent insulation performance. However, their manufacturing process is complex, and defects such as air bubbles and gaps are easily generated inside the dry bushing during manufacturing, which leads to a decrease in insulation performance and threatens equipment safety. Therefore, in order to ensure that the dry bushings produced are free of defects such as air bubbles and gaps, it is necessary to randomly select individual dry bushings and perform defect detection by slicing and sampling.

[0003] When performing defect detection on dry bushings using conventional techniques, traditional ultrasonic phased array testing (PAUT) can be used. PAUT is an efficient and accurate non-destructive testing method that uses ultrasonic principles to detect defects in materials or equipment, and is commonly used for inspecting metals, welds, and composite materials. However, due to the influence of air bubbles and irregular gaps, conventional PAUT methods cannot accurately locate the specific position of air bubbles in dry bushings because air bubbles interfere with the ultrasonic signal reflection during defect detection. Therefore, an improved ultrasonic phased array testing method is proposed to perform defect detection on dry bushings. Summary of the Invention

[0004] This invention provides a dry sleeve defect detection method and system based on ultrasonic phased array, which solves the problem of signal interference caused by air bubbles in existing methods.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] The first aspect of this invention is to provide a method for detecting defects in dry bushings based on an ultrasonic phased array, comprising:

[0007] Obtain a plane wave deflection angle sequence consisting of several plane wave deflection angles; obtain the full matrix data corresponding to each deflection angle in the plane wave deflection angle sequence through an ultrasonic phased array detection system; obtain the focusing delay of each transmitting array element at each deflection angle;

[0008] Acquire single-plane wave imaging corresponding to each deflection angle in the deflection angle sequence; acquire the acoustic path from each pixel to each transmitting element and each receiving element in the single-plane wave imaging corresponding to each deflection angle; based on the acoustic path and the focusing delay of each transmitting element, obtain the total flight time from each pixel to each transmitting element and each receiving element in the single-plane wave imaging; based on the total flight time and the full matrix data corresponding to the single-plane wave imaging corresponding to each deflection angle, obtain the superimposed signal intensity of each pixel in the single-plane wave imaging corresponding to each deflection angle; based on the superimposed signal intensity of pixels at the same position in the single-plane wave imaging corresponding to all deflection angles in the deflection angle sequence, obtain the coherence factor of each pixel at each position; adjust the superimposed signal intensity of pixels at the same position in the single-plane wave imaging corresponding to all deflection angles in the deflection angle sequence using the coherence factor to obtain a weighted composite image;

[0009] The weighted composite image is enhanced to obtain an enhanced composite image; the enhanced composite image is segmented to obtain several new connected components; the bubble defect connected components are selected from all the new connected components by their area.

[0010] Furthermore, obtaining the focusing delay of each transmitting element at each deflection angle includes:

[0011]

[0012] In the formula, Indicates the first The launch deflection angle of each launch element This represents the speed of sound of a wave in a medium. Indicates the first Focusing delay of each transmitting element Indicates the first The distance between each transmitting element and the center of the array.

[0013] Further, the acquisition of single-plane wave imaging corresponding to each deflection angle in the deflection angle sequence; acquisition of the acoustic path from each pixel to each transmitting element and each receiving element in the single-plane wave imaging corresponding to each deflection angle; and obtaining the total flight time from each pixel to each transmitting element and each receiving element in the single-plane wave imaging based on the acoustic path and the focusing delay of each transmitting element, including:

[0014] Single-plane wave imaging corresponding to each deflection angle in the deflection angle sequence is obtained by using a plane wave composite imaging algorithm.

[0015]

[0016]

[0017] In the formula, This represents the coordinates of a pixel in a single-plane wave image. Indicates the launch array element coordinates Indicates receiving array element The coordinates; This represents the distance from each pixel in single-plane wave imaging to the transmitting array element. The distance between the two, This represents the distance from each pixel in single-plane wave imaging to the receiving array element. The distance between them;

[0018]

[0019] In the formula, Indicates the launch array element Focusing delay, Indicates the speed of sound of longitudinal waves. This represents the distance from each pixel in single-plane wave imaging to the transmitting array element. and receiving array elements Total flight time.

[0020] Further, the step of obtaining the superimposed signal intensity of each pixel in the single-plane wave imaging corresponding to each deflection angle based on the total flight time and the full matrix data corresponding to each deflection angle includes:

[0021]

[0022] In the formula, This represents the distance from each pixel in single-plane wave imaging to the transmitting array element. and receiving array elements Total flight time Indicates To find the corresponding signal strength in the full matrix data for the index; This indicates the total number of elements in the transmitting array. This represents the total number of receiving array elements. This represents the superimposed signal intensity of each pixel in single-plane wave imaging corresponding to each deflection angle.

[0023] Further, the step of obtaining the coherence factor of each pixel at each position based on the superimposed signal intensity of pixels at the same position in single-plane wave imaging corresponding to all deflection angles in the deflection angle sequence includes:

[0024]

[0025] In the formula, Indicates the first deflection angle in the sequence. The position coordinates in a single-plane wave image corresponding to each deflection angle are: The superimposed signal strength of the corresponding pixel This indicates the number of all deflection angles in the deflection angle sequence. Represents the absolute value symbol. The position coordinates are The coherence factor of the corresponding pixel.

[0026] Further, the step of adjusting the superimposed signal intensity of pixels at the same position in single-plane wave imaging corresponding to all deflection angles in the deflection angle sequence through the coherence factor to obtain a weighted composite image includes:

[0027]

[0028] In the formula, Indicates the first deflection angle in the sequence. The position coordinates in a single-plane wave image corresponding to each deflection angle are: The superimposed signal strength of the corresponding pixel This indicates the number of all deflection angles in the deflection angle sequence. The position coordinates are The coherence factor corresponding to the pixel. The position coordinates in the fused image are: The superimposed signal strength of the corresponding pixel;

[0029] A weighted composite image is formed by superimposing the signal intensities of corresponding pixels at all locations in the fused image.

[0030] Further, the process of enhancing the weighted composite image to obtain an enhanced composite image; segmenting the enhanced composite image to obtain several new connected components; and filtering out the bubble defect connected components from all new connected components by their area, includes:

[0031] The weighted composite image is enhanced using a linear enhancement algorithm to obtain an enhanced composite image; the enhanced composite image is then segmented using semantic segmentation to obtain several connected components; the neural network structure corresponding to the semantic segmentation is a U-Net network, and an SE Block channel attention module is embedded in the skip connections of the U-Net network;

[0032] A morphological closing operation is performed on several connected components to obtain several new connected components after processing; the area of ​​all new connected components is linearly normalized to obtain the normalized area of ​​the new connected components; all new connected components whose normalized area is less than a preset first reference area threshold and greater than a preset second reference area threshold are taken as bubble defect connected components.

[0033] A second aspect of the present invention is to provide a dry sleeve defect detection system based on an ultrasonic phased array, comprising:

[0034] Data acquisition module: used to acquire a plane wave deflection angle sequence consisting of several plane wave deflection angles; to acquire the full matrix data corresponding to each deflection angle in the plane wave deflection angle sequence through an ultrasonic phased array detection system; and to acquire the focusing delay of each transmitting array element at each deflection angle.

[0035] Image fusion module: This module acquires single-plane wave imaging corresponding to each deflection angle in the deflection angle sequence; acquires the acoustic path from each pixel to each transmitting element and each receiving element in the single-plane wave imaging corresponding to each deflection angle; obtains the total flight time from each pixel to each transmitting element and each receiving element in the single-plane wave imaging based on the acoustic path and the focusing delay of each transmitting element; acquires the superimposed signal intensity of each pixel in the single-plane wave imaging corresponding to each deflection angle based on the total flight time and the full matrix data corresponding to the single-plane wave imaging corresponding to each deflection angle; acquires the coherence factor of each pixel at each position based on the superimposed signal intensity of pixels at the same position in the single-plane wave imaging corresponding to all deflection angles in the deflection angle sequence; and adjusts the superimposed signal intensity of pixels at the same position in the single-plane wave imaging corresponding to all deflection angles in the deflection angle sequence using the coherence factor to obtain a weighted composite image.

[0036] Defect detection module: used to enhance the weighted composite image to obtain an enhanced composite image; segment the enhanced composite image to obtain several new connected regions; filter out the bubble defect connected regions from all new connected regions by their area.

[0037] A third aspect of the present invention is to provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the aforementioned method for detecting dry bushing defects based on an ultrasonic phased array.

[0038] A fourth aspect of the present invention is to provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the aforementioned method for detecting defects in dry bushings based on an ultrasonic phased array.

[0039] Compared with the prior art, the beneficial effects of the present invention are: obtaining the acoustic path from each pixel to each transmitting element and each receiving element in single-plane wave imaging corresponding to each deflection angle; obtaining the total flight time from each pixel to each transmitting element and each receiving element in single-plane wave imaging based on the acoustic path and the focusing delay of each transmitting element, thereby improving the accuracy of ultrasound time analysis; obtaining the superimposed signal intensity of each pixel in single-plane wave imaging corresponding to each deflection angle based on the total flight time and the full matrix data corresponding to single-plane wave imaging at each deflection angle, thereby improving the accuracy of superimposed signal intensity analysis; and obtaining the superimposed signal intensity of each pixel in single-plane wave imaging at each deflection angle based on the total flight time and the full matrix data corresponding to single-plane wave imaging at each deflection angle, thereby improving the accuracy of superimposed signal intensity analysis. The coherence factor of each pixel at a given position is obtained by superimposing the signal intensity of pixels at the same position in single-plane wave imaging corresponding to a deflection angle. Using this coherence factor, the superimposed signal intensity of pixels at the same position in single-plane wave imaging corresponding to all deflection angles in the deflection angle sequence is adjusted to obtain a weighted composite image, improving the accuracy of weighted fusion of multiple images. The weighted composite image is then enhanced to obtain an enhanced composite image. This enhanced composite image is then segmented to obtain several new connected components, improving the accuracy of image post-processing. Finally, bubble defect connected components are selected from all new connected components by their area, improving the accuracy of dry sleeve defect detection. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This invention provides a schematic flowchart of a method for detecting defects in dry bushings based on an ultrasonic phased array.

[0042] Figure 2 This invention provides a schematic diagram of the module flow of a dry bushing defect detection system based on an ultrasonic phased array.

[0043] Figure 3 A schematic diagram of the dry bushing defect detection process;

[0044] Figure 4 This is a schematic diagram showing the process before and after dry cannula imaging.

[0045] Figure 5 This is a schematic diagram of dry bushing defect detection. Detailed Implementation

[0046] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0047] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0048] To address the problems existing in the background technology, a dry sleeve defect detection method and system based on ultrasonic phased array has been designed, which has important practical significance.

[0049] like Figure 1 As shown, the first aspect of the present invention is to provide a method for detecting defects in dry bushings based on an ultrasonic phased array, comprising the following steps:

[0050] Step S001: Build an ultrasonic phased array detection system, obtain full matrix data of dry cannula slices through the ultrasonic phased array detection system, and obtain the focusing delay of each transmitting element at each deflection angle.

[0051] It should be noted that, in order to detect defects such as air bubbles and gaps that are prone to occur inside the dry bushing during the manufacturing process, it is necessary to collect initial images of the dry bushing sections for defect anomaly detection.

[0052] Specifically, firstly, surface oil and other impurities are removed from the dry sheath slice; then, an ultrasonic phased array detection system is built, which includes a phased array probe, a signal generator, a data acquisition module, and an imaging processing unit; water is used as an ultrasonic coupling agent and placed between the dry sheath slice and the ultrasonic phased array wedge to reduce wave loss.

[0053] A high-precision excitation pulse is generated using a signal generator to control the acoustic beam formation. A plane wave is then emitted into the dry sheath via a phased array probe. The data acquisition module collects the echo signal, performs digital processing, and obtains full matrix data of the dry sheath slice. The ultrasonic phased array contains 64 elements, a center frequency of 5 MHz, and a medium sound velocity of [missing information]. The coupling medium is water, and the scanning method is A-scan.

[0054] It should be noted that in order to optimize imaging quality, improve image resolution, and enhance the signal-to-noise ratio, multiple deflection angles are introduced during plane wave emission to improve image clarity.

[0055] Specifically, multiple deflection angles are introduced to form a plane wave deflection angle sequence; wherein, in this embodiment, the plane wave deflection angle sequence is as follows: ; Obtain the full matrix data corresponding to each deflection angle in the plane wave deflection angle sequence. The deflection angle at the time of plane wave emission is determined by the focusing delay of plane wave imaging; the formula corresponding to the focusing delay of plane wave imaging is:

[0056]

[0057] In the formula, Indicates the first The launch deflection angle of each launch element This represents the speed of sound of a wave in a medium. Indicates the first Focusing delay of each transmitting element Indicates the first The distance between each transmitting element and the center of the array.

[0058] Step S002: Obtain single-plane wave imaging through full matrix data, and fuse all single-plane wave images to obtain a weighted composite image.

[0059] A plane wave composite imaging algorithm is used to obtain single-plane wave images corresponding to each deflection angle in the deflection angle sequence; thus, single-plane wave images corresponding to all deflection angles in the deflection angle sequence are obtained. Then, a full-focusing algorithm is used to combine the single-plane wave images corresponding to all deflection angles in the deflection angle sequence to obtain a final full-focusing image. The specific process of obtaining the full-focusing image using the full-focusing algorithm is as follows:

[0060] Obtain the acoustic path from each pixel in the single-plane wave imaging to each transmitting element and each receiving element for each deflection angle; specifically expressed by the formula:

[0061]

[0062]

[0063] In the formula, This represents the coordinates of a pixel in a single-plane wave image. Indicates the launch array element coordinates Indicates receiving array element The coordinates; This represents the distance from each pixel in single-plane wave imaging to the transmitting array element. The distance between the two, This represents the distance from each pixel in single-plane wave imaging to the receiving array element. The distance between the sounds.

[0064] Based on the acoustic path between each pixel and each transmitting and receiving element in single-plane wave imaging for each deflection angle, and the focusing delay of each transmitting element, the total flight time between each pixel and each transmitting and receiving element in single-plane wave imaging is obtained; the total flight time is specifically expressed by the formula:

[0065]

[0066] In the formula, Indicates the launch array element Focusing delay, Indicates the speed of sound of longitudinal waves. This represents the distance from each pixel in single-plane wave imaging to the transmitting array element. and receiving array elements Total flight time.

[0067] Based on the total flight time from each pixel to each transmitting element and each receiving element in single-plane wave imaging, and the full matrix data corresponding to single-plane wave imaging, the superimposed signal intensity of each pixel in single-plane wave imaging corresponding to each deflection angle is obtained; the superimposed signal intensity of each pixel in single-plane wave imaging is specifically expressed by the formula:

[0068]

[0069] In the formula, This represents the distance from each pixel in single-plane wave imaging to the transmitting array element. and receiving array elements Total flight time Indicates To find the corresponding signal strength in the full matrix data for the index; This indicates the total number of elements in the transmitting array. This represents the total number of receiving array elements. This represents the superimposed signal intensity of each pixel in single-plane wave imaging corresponding to each deflection angle.

[0070] Based on the superimposed signal intensity of pixels at the same position in single-plane wave imaging corresponding to all deflection angles in the deflection angle sequence, the coherence factor of each pixel at each position is obtained; the coherence factor is specifically expressed by the formula:

[0071]

[0072] In the formula, Indicates the first deflection angle in the sequence. The position coordinates in a single-plane wave image corresponding to each deflection angle are: The superimposed signal strength of the corresponding pixel This indicates the number of all deflection angles in the deflection angle sequence. Represents the absolute value symbol. The position coordinates are The coherence factor of the corresponding pixel.

[0073] By adjusting the coherence factor of each pixel at each position, the superimposed signal intensity of pixels at the same position in the single-plane wave imaging corresponding to all deflection angles in the deflection angle sequence is adjusted to obtain the superimposed signal intensity of pixels at each position in the fused image; the superimposed signal intensity of pixels at each position in the fused image is specifically expressed by the formula:

[0074]

[0075] In the formula, Indicates the first deflection angle in the sequence. The position coordinates in a single-plane wave image corresponding to each deflection angle are: The superimposed signal strength of the corresponding pixel This indicates the number of all deflection angles in the deflection angle sequence. The position coordinates are The coherence factor corresponding to the pixel. The position coordinates in the fused image are: The superimposed signal strength of the corresponding pixel.

[0076] A weighted composite image is formed by superimposing the signal intensities of corresponding pixels at all locations in the weighted composite image. The schematic diagrams before and after dry cannula imaging are shown below. Figure 4 As shown. Among them, by Figure 4It can be seen that neither the TFM (Total Focusing Method) image nor the coherence factor image effectively suppressed the sidelobe signal; instead, it led to an expansion of the artifact range and a significant attenuation of the main lobe signal intensity, thereby weakening the discernibility of defect features. In contrast, the weighted TFM image, which intelligently suppresses the sidelobe signal and directionally enhances the main lobe signal, clearly presents the contour features of minute defects and accurately analyzes their spatial distribution parameters, achieving the best detection effect. The weighted TFM image is thus a weighted composite image.

[0077] Thus, the weighted composite image is obtained using the above method.

[0078] Step S003: Post-process and segment the weighted composite image to obtain several new connected components; filter out the bubble defect connected components from all the new connected components by their area.

[0079] It should be noted that, due to the presence of noise interference in the surrounding environment during the acquisition of the weighted composite image, it is necessary to enhance the weighted composite image in order to improve the accuracy of the image information.

[0080] Specifically, the weighted composite image is enhanced using a linear enhancement algorithm to obtain an enhanced composite image; the linear enhancement algorithm is a well-known technique and will not be described in detail here.

[0081] Then, the enhanced composite image is segmented through semantic segmentation to obtain several connected components. In this embodiment, the neural network structure corresponding to semantic segmentation is a U-Net network, and the loss function of the U-Net network (U-shaped network) in this embodiment is the cross-entropy loss function. Both the U-Net network and the cross-entropy loss function are well-known technologies and will not be described in detail here.

[0082] The U-Net network includes structures such as encoders, decoders, and skip connections. Among them, the skip connections embed SE Block (Squeeze-and-Excitation Block) channel attention modules to enhance the feature weights of defective regions.

[0083] In this method, edges, textures, colors, shapes, and gradients are used as channels to determine the corresponding convolutional kernels, and specific convolutional kernels are used to obtain the corresponding feature maps. Edges and gradients are obtained using the Sobel operator; the Sobel operator is a well-known technique and will not be described in detail here.

[0084] Thus, the U-Net network described above typically obtains several connected components in the enhanced composite image.

[0085] Morphological closing operations are performed on several connected components to obtain several new connected components after processing. The morphological closing operation expands the foreground region through dilation and restores the main structure of the image through erosion, which serves to fill small holes and remove small noise points.

[0086] Morphological closing operations are well-known techniques and will not be elaborated upon here.

[0087] It should be noted that, in order to prevent interference from the connected components corresponding to isolated noise points, it is also necessary to filter out the connected components corresponding to isolated noise points.

[0088] It should be further explained that since the connected regions corresponding to bubble defects and isolated noise points are both relatively small, they can be filtered out by the area of ​​the connected regions. Furthermore, since the connected regions corresponding to isolated noise points are smaller than the connected regions corresponding to bubble defects, two area thresholds are set to filter out bubble defects.

[0089] Specifically, the areas of all new connected components are linearly normalized to obtain the normalized areas of the new connected components; and the normalized areas of all new connected components are less than a preset first reference area threshold. And greater than the preset second reference area threshold The new connected component is used as the bubble defect connected component.

[0090] In this embodiment, a first reference area threshold is preset. Preset second reference area threshold In this embodiment, a preset first reference area threshold is used. and preset second reference area threshold No specific restrictions are imposed; implementers can decide based on the specific circumstances.

[0091] Thus, the connected domain of the defect bubble is obtained using the above method. A schematic diagram of the dry bushing defect detection process is shown below. Figure 3 As shown in the figure. The schematic diagram for dry casing defect detection is shown below. Figure 5 As shown. Among them, Figure 5 In the image, due to the multi-layered structure of the casing and the presence of other minor defects, it appears as small green clouds; blue indicates the basic low-amplitude echo signal with no defects; red indicates the high-amplitude ultrasonic echo signal, indicating the presence of various defects or inclusions.

[0092] like Figure 2 As shown, a second aspect of the present invention is to provide a dry sleeve defect detection system based on an ultrasonic phased array, comprising the following modules:

[0093] Data acquisition module 101: used to acquire a plane wave deflection angle sequence composed of several plane wave deflection angles; to acquire the full matrix data corresponding to each deflection angle in the plane wave deflection angle sequence through an ultrasonic phased array detection system; and to acquire the focusing delay of each transmitting array element at each deflection angle.

[0094] Image fusion module 102: Used to acquire single-plane wave imaging corresponding to each deflection angle in the deflection angle sequence; acquire the acoustic path from each pixel to each transmitting element and each receiving element in the single-plane wave imaging corresponding to each deflection angle; obtain the total flight time from each pixel to each transmitting element and each receiving element in the single-plane wave imaging based on the acoustic path and the focusing delay of each transmitting element; obtain the superimposed signal intensity of each pixel in the single-plane wave imaging corresponding to each deflection angle based on the total flight time and the full matrix data corresponding to the single-plane wave imaging corresponding to each deflection angle; obtain the coherence factor of each pixel corresponding to each position based on the superimposed signal intensity of pixels at the same position in the single-plane wave imaging corresponding to all deflection angles in the deflection angle sequence; adjust the superimposed signal intensity of pixels at the same position in the single-plane wave imaging corresponding to all deflection angles in the deflection angle sequence using the coherence factor to obtain a weighted composite image;

[0095] Defect detection module 103: used to enhance the weighted composite image to obtain an enhanced composite image; to segment the enhanced composite image to obtain several new connected regions; and to filter out the bubble defect connected regions from all the new connected regions by the area of ​​the new connected regions.

[0096] A third aspect of the present invention is to provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement a dry bushing defect detection method based on an ultrasonic phased array.

[0097] A fourth aspect of the present invention is to provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements a method for detecting defects in dry bushings based on an ultrasonic phased array.

[0098] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, optical storage, etc.) containing computer-usable program code.

[0099] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, systems, and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0100] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0101] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for detecting defects in dry bushings based on ultrasonic phased array, characterized in that, include: Obtain a plane wave deflection angle sequence consisting of several plane wave deflection angles; obtain the full matrix data corresponding to each deflection angle in the plane wave deflection angle sequence through an ultrasonic phased array detection system; obtain the focusing delay of each transmitting array element at each deflection angle; Obtain the single-plane wave imaging corresponding to each deflection angle in the deflection angle sequence; obtain the acoustic path from each pixel to each transmitting element and each receiving element in the single-plane wave imaging corresponding to each deflection angle; and, based on the acoustic path and the focusing delay of each transmitting element, obtain the total flight time from each pixel to each transmitting element and each receiving element in the single-plane wave imaging, including: Single-plane wave imaging corresponding to each deflection angle in the deflection angle sequence is obtained by using a plane wave composite imaging algorithm. ； ； In the formula, ( x , z ) represents the coordinates of a pixel in single-plane wave imaging. x t ,0) indicates the transmitting array element t coordinates, ( x r ,0) indicates the receiving array element r The coordinates; d t This represents the distance from each pixel in single-plane wave imaging to the transmitting array element. t The distance between the sounds, d r This represents the distance from each pixel in single-plane wave imaging to the receiving array element. r The distance between the sounds; ； In the formula, Indicates the launch array element t Focusing delay, v 1 represents the longitudinal wave speed. f t,r This represents the distance from each pixel in single-plane wave imaging to the transmitting array element. t and receiving array elements r Total flight time; Based on the total flight time and the full matrix data corresponding to the single-plane wave imaging at each deflection angle, the superimposed signal intensity of each pixel in the single-plane wave imaging at each deflection angle is obtained; based on the superimposed signal intensity of pixels at the same position in the single-plane wave imaging at all deflection angles in the deflection angle sequence, the coherence factor of the pixel at each position is obtained, including: ； In the formula, Indicates the first deflection angle in the sequence. i The position coordinates in a single-plane wave image corresponding to each deflection angle are ( x , z The superimposed signal strength of the corresponding pixel. M This represents the number of deflection angles in the deflection angle sequence, and || represents the absolute value sign. CF ( x , z ) indicates that the position coordinates are ( x , z The coherence factor of the corresponding pixel; By using the coherence factor, the superimposed signal intensity of pixels at the same position in single-plane wave imaging corresponding to all deflection angles in the deflection angle sequence is adjusted to obtain a weighted composite image, including: ； In the formula, Indicates the first deflection angle in the sequence. i The position coordinates in a single-plane wave image corresponding to each deflection angle are ( x , z The superimposed signal strength of the corresponding pixel. M This indicates the number of all deflection angles in the deflection angle sequence. CF ( x , z ) indicates that the position coordinates are ( x , z The coherence factor corresponding to the pixel. This represents the superimposed signal strength at the corresponding pixel coordinates in the fused image; A weighted composite image is formed by superimposing the signal intensities of corresponding pixels at all locations in the fused image. The weighted composite image is enhanced to obtain an enhanced composite image; the enhanced composite image is segmented to obtain several new connected components; the bubble defect connected components are selected from all new connected components by their area, including enhancing the weighted composite image using a linear enhancement algorithm to obtain an enhanced composite image; and segmenting the enhanced composite image using semantic segmentation to obtain several connected components; wherein the neural network structure corresponding to semantic segmentation is a U-Net network, and an SE Block channel attention module is embedded in the skip connections of the U-Net network; A morphological closing operation is performed on several connected components to obtain several new connected components after processing; the area of ​​all new connected components is linearly normalized to obtain the normalized area of ​​the new connected components; all new connected components whose normalized area is less than a preset first reference area threshold and greater than a preset second reference area threshold are taken as bubble defect connected components. The ultrasonic phased array has 64 array elements, a center frequency of 5 MHz, and a medium sound velocity of 2700 m / s. m / s The coupling medium is water, and the scanning method is A-scan.

2. The method for detecting defects in dry bushings based on ultrasonic phased array according to claim 1, characterized in that, The acquisition of the focusing delay of each transmitting element at each deflection angle includes: ； In the formula, Indicates the first j The launch deflection angle of each launch element c This represents the speed of sound of a wave in a medium. Indicates the first j Focusing delay of each transmitting element x j Indicates the first j The distance between each transmitting element and the center of the array.

3. The method for detecting defects in dry bushings based on ultrasonic phased array according to claim 1, characterized in that, The full matrix data corresponding to the single-plane wave imaging for each deflection angle based on the total flight time; Obtain the superimposed signal intensity of each pixel in single-plane wave imaging corresponding to each deflection angle, including: ； In the formula, This represents the distance from each pixel in single-plane wave imaging to the transmitting array element. t and receiving array elements r Total flight time Indicated by To find the corresponding signal strength in the full matrix data for the index; N 1 represents the total number of transmitting array elements. N 2 represents the total number of receiving array elements. I This represents the superimposed signal intensity of each pixel in single-plane wave imaging corresponding to each deflection angle.

4. A dry sleeve defect detection system based on ultrasonic phased array, characterized in that, It includes a data acquisition module, an image fusion module, and a defect detection module. When the data acquisition module, the image fusion module, and the defect detection module are executed, they implement the dry sleeve defect detection method based on ultrasonic phased array as described in claim 1.

5. An electronic device, characterized in that, The device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the dry sleeve defect detection method based on any one of claims 1-3.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the dry sleeve defect detection method based on ultrasonic phased array as described in any one of claims 1-3.

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