Cable lead sealing internal defect positioning method and system based on vector full focusing

Abstract

The invention provides a cable lead sealing internal defect positioning method based on vector full focusing, and the method comprises the steps: obtaining a transmitting array element, a receiving array element and an echo signal when a one-dimensional ultrasonic array scans a cable lead sealing in a full-matrix capture mode according to an array element combination mode; generating a signal intensity distribution image according to the echo signal by using a full-focus algorithm; selecting a defect signal and a position coincidence condition from the signal intensity distribution image to obtain a defect point and a position; constructing a vector coordinate system and registering the vector coordinate system with the signal intensity distribution image to obtain the vector length and direction of the defect signal; obtaining the defect type of the defect point according to the vector length, direction and position coincidence condition of the defect signal; and a three-dimensional model of cable lead sealing is simulated on the global coordinate system, and automatic positioning and labeling are performed according to the position and the defect type of each defect point. By implementing the method, the problems of directional information loss, high small defect omission ratio, poor complex structure adaptability and the like which generally exist in the existing mode can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of power cable detection, and in particular to a method and system for locating internal defects of cable seals based on vector full focusing. Background Art

[0002] Cable seals, as the core sealing structure of power cable joints, play a crucial role in isolating them from external environmental corrosion and maintaining internal insulation performance. However, due to the long-term influence of mechanical stress, thermal expansion, and chemical corrosion, the seal material is prone to internal defects such as cracks, pores, and delamination. If these defects are not detected in a timely manner, they can lead to serious accidents such as seal failure, insulation breakdown, and even cable explosion. Therefore, the development of high-precision and high-sensitivity seal defect detection technology is crucial to ensure the safe operation of power systems.

[0003] Among the current mainstream inspection technologies, eddy current testing, limited by the principle of electromagnetic induction, can only identify surface cracks but cannot detect internal or interfacial defects. While laser ultrasonic testing can adapt to curved structures, the equipment is bulky, expensive, and difficult to meet on-site environmental requirements. The DC resistance method, relying on the uniformity of material conductivity, is insensitive to submillimeter defects. Ultrasonic phased array technology improves imaging capabilities through dynamic focusing, but its imaging mode, based on single-directional beam synthesis, is insensitive to defect directionality and exhibits significant measurement errors for defect sizes smaller than the beam width, making it difficult to accurately characterize crack extension directions or the spatial distribution of complex-shaped defects.

[0004] However, the above detection methods generally have problems such as lack of directional information, high rate of missed detection of minor defects, and poor adaptability to complex structures.

[0005] Therefore, it is necessary to provide a new method for locating internal defects of cable seals, which can solve the problems commonly found in existing methods, such as lack of directional information, high rate of missed detection of minor defects, and poor adaptability to complex structures. Summary of the Invention

[0006] The technical problem to be solved by the embodiments of the present invention is to provide a method and system for locating internal defects of cable sealing lead based on vector full focusing, which can solve the problems commonly existing in existing methods such as lack of directional information, high missed detection rate of minor defects, and poor adaptability to complex structures.

[0007] In order to solve the above technical problems, an embodiment of the present invention provides a method for locating internal defects of cable lead seals based on vector full focusing, the method comprising the following steps:

[0008] S1. When a one-dimensional ultrasonic array sequentially scans the cable sealing lead according to multiple predetermined array element combinations and in a full-matrix capture mode, the transmitting array elements and receiving array elements activated each time in each array element combination are obtained, as well as the echo signal and sound wave transmission time received by each receiving array element, and the position of each transmitting unit and its corresponding receiving unit in each array element combination in a preset global coordinate system is further obtained; wherein each array element combination is obtained by extracting an equal number of array elements from the one-dimensional ultrasonic array and combining them, and there is some overlap between the array elements of the adjacent array element combination; the full-matrix capture mode is a method for traversing the preset transmitting-receiving combinations in each array element combination according to the excitation order predetermined in each array element combination to excite and receive ultrasound; the transmitting-receiving combinations in each array element combination are indexed by each array element as a transmitting array element, and are composed of a one-to-many mapping between each transmitting array element and all other array elements in the same array element combination except itself as receiving array elements; the number of receiving array elements in each transmitting-receiving combination is the same;

[0009] S2. Using a total focusing algorithm, perform phase compensation and signal superposition on all echo signals obtained in each array element combination, and combine the positions of each transmitting unit and its corresponding receiving unit in each array element combination in the global coordinate system to generate a three-dimensional signal intensity distribution image based on the scanning of the cable seal by each array element combination;

[0010] S3. Selecting defect signals that meet predetermined intensity matching conditions in each signal intensity distribution image, and determining each defect point and its position on the global coordinate system based on the position overlap of the defect signals in each signal intensity distribution image; wherein the position overlap of the defect signals includes the overlapping defect signals and the associated signal intensity distribution images;

[0011] S4. Constructing a vector coordinate system, and after registering each of the signal intensity distribution images with the vector coordinate system, determining the vector length and direction of each defect signal in each of the signal intensity distribution images; wherein the vector length of each defect signal indicates the intensity of the signal, and the vector direction indicates the direction of the signal toward the vector origin;

[0012] S5. Based on the vector length, vector direction, and position overlap of each defect signal in each signal intensity distribution image, perform unified vector calculation on the defect signals that overlap at the same position to obtain the defect type of each defect point; wherein the defect types include cracks and holes; if the vector length after the unified vector calculation of the defect signals that overlap at the same position is greater than any vector length before the calculation, the obtained defect type is a crack; if the vector length after the unified vector calculation of the defect signals that overlap at the same position is less than any vector length before the calculation, the obtained defect type is a hole;

[0013] S6. Based on the actual physical structure of the cable seal, a three-dimensional model of the cable seal is simulated on the global coordinate system, and each defect point is automatically located and marked on the three-dimensional model of the cable seal according to its position and defect type on the global coordinate system.

[0014] Wherein, the step S1 specifically includes:

[0015] Determine a plurality of predefined array element combinations of a one-dimensional ultrasonic array and their corresponding full-matrix capture modes; wherein each array element combination is obtained by extracting an equal number of array elements from the one-dimensional ultrasonic array and combining them, and there is partial overlap of array elements between adjacent array element combinations; the full-matrix capture mode is a mode for traversing the preset transmit-receive combinations in each array element combination according to the excitation sequence predetermined in each array element combination to perform ultrasonic excitation and reception; the transmit-receive combinations in each array element combination are indexed by each array element as a transmit array element, and are composed of a one-to-many mapping of each transmit array element with all other array elements in the same array element combination except itself as receive array elements; the number of receive array elements in each transmit-receive combination is the same;

[0016] When the one-dimensional ultrasonic array sequentially scans the cable sealing lead according to multiple array element combinations and in a full matrix capture mode, the transmitting array element and the receiving array element activated each time in each array element combination are obtained, and the echo signal received by each receiving array element and the sound wave transmission time are obtained;

[0017] Based on the initial position of the one-dimensional ultrasonic array, a global coordinate system is constructed, and according to the preset spacing between the array elements in the one-dimensional ultrasonic array, the position of each transmitting unit and its corresponding receiving unit in each array element combination in the global coordinate system is obtained.

[0018] Wherein, the step S2 specifically includes:

[0019] Acquire the echo signal s obtained by scanning the cable sealing lead based on each array element combination modeik (t); where i is the transmitting unit index, and i=1, 2, ..., N; k is the receiving unit index, and j=1, 2, ..., N-1; t is the time variable;

[0020] Determine each echo signal s ik (t) Compensated phase time t i,k (r); where and d i (r)=||rr i ||, d k (r)=||rr k ||; c is the predetermined sound velocity of ultrasound in the cable seal; d i (r) is the distance of the acoustic wave transmission path from the transmitting unit i to the imaging point r; d k (r) is the distance of the acoustic wave transmission path from the reflected echo of the imaging point r to the receiving unit k; r i and r k are the positions of the transmitting unit i and the receiving unit k in the global coordinate system respectively; ||·|| is the Euclidean norm;

[0021] Each echo signal s ik (t) at the corresponding compensation phase time t i,k The amplitudes at (r) are coherently superimposed to generate a three-dimensional signal intensity distribution image I obtained by scanning the cable sealing lead in each array element combination mode. j (r); where N is the total number of array elements in any array element combination, which is a positive even number.

[0022] Wherein, the step S3 specifically includes:

[0023] In each signal intensity distribution image, an echo signal having a predetermined intensity matching condition and a signal intensity greater than a predetermined intensity threshold is selected as a defect signal;

[0024] Based on the positions of the transmitting unit and the receiving unit corresponding to each defect signal in the global coordinate system and the acoustic wave transmission time of each defect signal, the position of the defect point generating the defect signal in the global coordinate system is simulated, and the position overlap of the defect signals is further determined; wherein the position overlap of the defect signals includes the overlapping defect signals and the associated signal intensity distribution images;

[0025] All defect signals overlapping at the same position are identified as echo signals of the same defect point, and a position on the global coordinate system is selected from all defect signals overlapping at the same position to output the position of the corresponding defect point on the global coordinate system.

[0026] Wherein, the step S4 specifically includes:

[0027] Construct a vector coordinate system;

[0028] Each of the signal intensity distribution images is aligned in the vector coordinate system, and the center point of each of the signal intensity distribution images is made to coincide with the vector origin on the vector coordinate system, and the vector length and direction of each defect signal in each of the signal intensity distribution images are further obtained; wherein the vector length of each defect signal is used to indicate the intensity of the signal, and the vector direction is used to indicate the direction of the signal pointing to the vector origin.

[0029] Wherein, the step S5 specifically includes:

[0030] According to the vector length, vector direction and position overlap of each defect signal in each signal intensity distribution image, the vector length and direction of the defect signal that overlaps at the same position contained in each defect point are selected to perform unified vector calculation;

[0031] If the length of the vector after unified vector calculation of the overlapping defect signals at the same position contained in a certain defect point is greater than any vector length before calculation, then the defect type of the defect point is obtained as a crack;

[0032] If the length of the vector after unified vector calculation of the overlapping defect signals at the same position contained in a certain defect point is less than any vector length before calculation, the defect type of the defect point is obtained as a hole.

[0033] Wherein, the step S6 specifically includes:

[0034] According to the actual physical structure of the cable seal, a three-dimensional model of the cable seal is simulated in the global coordinate system using simulation software;

[0035] According to the position of each defect point on the global coordinate system and the defect type, automatic positioning and marking are performed on the three-dimensional model of the cable lead seal.

[0036] The embodiment of the present invention further provides a cable lead seal internal defect location system based on vector full focusing, comprising:

[0037] The scanning and full-matrix capture unit is used to obtain the transmitting array elements and receiving array elements enabled each time in each array element combination mode, and obtain the echo signal and sound wave transmission time received by each receiving array element, and further obtain the position of each transmitting unit and its corresponding receiving unit in each array element combination mode on a preset global coordinate system; wherein, each array element combination mode is obtained by extracting an equal number of array elements from the one-dimensional ultrasonic array and combining them, and its Adjacent array element combinations have some overlapping array elements. The full-matrix capture mode is a method for traversing the preset transmit-receive combinations in each array element combination according to the excitation sequence predetermined in each array element combination to excite and receive ultrasound waves. The transmit-receive combinations in each array element combination are indexed by each array element as a transmit array element, and are composed of a one-to-many mapping between each transmit array element and all other array elements in the same array element combination except itself as receive array elements. The number of receive array elements in each transmit-receive combination is the same.

[0038] a TFM imaging data processing unit, configured to perform phase compensation and signal superposition on all echo signals acquired in each array element combination using a total focusing algorithm, and generate a three-dimensional signal intensity distribution image based on scanning of the cable seal by each array element combination in combination with the positions of each transmitting unit and its corresponding receiving unit in the global coordinate system;

[0039] The TFM image defect point screening unit is used to select defect signals that meet the predetermined intensity matching conditions in each signal intensity distribution image, and determine each defect point and its position on the global coordinate system based on the position overlap of the defect signals in each signal intensity distribution image; wherein the position overlap of the defect signals includes the overlapping defect signals and the associated signal intensity distribution images;

[0040] a defect point vector registration unit, configured to construct a vector coordinate system, and after registering each of the signal intensity distribution images with the vector coordinate system, determine the vector length and direction of each defect signal in each of the signal intensity distribution images; wherein the vector length of each defect signal indicates the intensity of the signal, and the vector direction indicates the direction of the signal toward the vector origin;

[0041] a defect point vector calculation unit, configured to perform unified vector calculation on the defect signals overlapping at the same position based on the vector length, vector direction, and position overlap of each defect signal in each signal intensity distribution image, to obtain a defect type for each defect point; wherein the defect types include cracks and holes; if the vector length after the unified vector calculation of the defect signals overlapping at the same position is greater than any vector length before the calculation, the obtained defect type is a crack; if the vector length after the unified vector calculation of the defect signals overlapping at the same position is less than any vector length before the calculation, the obtained defect type is a hole;

[0042] The defect positioning and marking unit is used to simulate a three-dimensional model of the cable seal on the global coordinate system according to the actual physical structure of the cable seal, and automatically locate and mark each defect point on the three-dimensional model of the cable seal according to the position of each defect point on the global coordinate system and the defect type.

[0043] The implementation of the embodiments of the present invention has the following beneficial effects:

[0044] 1. The present invention uses a one-dimensional ultrasonic array with partially overlapping elements and adopts a full-matrix capture mode to sequentially scan the cable lead seal to generate high-resolution total focusing function (TFM) images, thereby enhancing the ability to capture tiny defects. This solves the problems commonly encountered in existing methods, such as high missed detection rates for tiny defects and poor adaptability to complex structures.

[0045] 2. The present invention preliminarily realizes the extraction of spatial orientation characteristics of defect points by extracting the vector size and direction of overlapping defect signals at the same position, effectively improving the problem of missing directional information of tiny defects, and adopts unified vector calculation to obtain the defect type of each defect point, so that the morphology and directional characteristics of different types of defects can be clearly presented, thereby solving the problems of missing directional information and poor adaptability to complex structures that are common in existing methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying any creative work, other drawings obtained based on these drawings still fall within the scope of the present invention.

[0047] Figure 1 A flowchart of a method for locating internal defects of a cable seal based on vector full focusing provided by an embodiment of the present invention;

[0048] Figure 2A schematic structural diagram of a cable seal internal defect location system based on vector full focusing is provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be described in further detail below with reference to the accompanying drawings.

[0050] like Figure 1 As shown in FIG. 1 , a method for locating internal defects of a cable seal based on vector full focusing is provided in an embodiment of the present invention. The method includes the following steps:

[0051] Step S1: When the one-dimensional ultrasonic array sequentially scans the cable sealing lead according to multiple predetermined array element combinations and in a full matrix capture mode, the transmitting array element and the receiving array element activated each time in each array element combination are obtained, as well as the echo signal and the sound wave transmission time received by each receiving array element, and the position of each transmitting unit and its corresponding receiving unit in each array element combination in a preset global coordinate system are further obtained; wherein each array element combination is obtained by extracting an equal number of array elements from the one-dimensional ultrasonic array and combining them, and the array element combination is consistent with the adjacent array elements. There is some overlap between the array elements in the element combination mode; the full matrix capture mode is a mode for traversing the preset transmit-receive combinations in each array element combination mode according to the excitation order predetermined in each array element combination mode to excite and receive ultrasound; the transmit-receive combinations in each array element combination mode are indexed by each array element as a transmit array element, and are composed of a one-to-many mapping between each transmit array element and all other array elements in the same array element combination mode except itself as receive array elements; the number of receive array elements in each transmit-receive combination is the same;

[0052] The specific process is as follows: first, an ultrasonic array composed of a probe with array elements arranged in a single column or a single row is installed and fixed in position, and further multiple array element combinations for scanning the cable sealing lead and the echo signal capture method are formulated as a full-matrix capture mode; wherein each array element combination method is obtained by extracting an equal number of array elements from a one-dimensional ultrasonic array and combining them, and there is some overlap between the array elements and the adjacent array element combination methods; the full-matrix capture mode is a method for traversing the preset transmit-receive combinations in each array element combination method according to the excitation order predetermined in each array element combination method (such as a first-in-first-out arrangement order) to excite and receive ultrasonic waves; the transmit-receive combinations in each array element combination method are indexed by each array element as a transmit array element, and are composed of a one-to-many mapping method in which each transmit array element and all other array elements in the same array element combination method except itself are used as receive array elements; the number of receive array elements in each transmit-receive combination is the same.

[0053] In one example, the total number of array elements in a one-dimensional ultrasound array is 3N, the array element spacing is d, the number of array elements extracted in each array element combination is N, and N / 2 array elements overlap in two adjacent array element combinations, where N is a positive even number.

[0054] For example, a one-dimensional ultrasonic array includes five element combinations. The last N / 2 elements in any element combination overlap with the first N / 2 elements in the next adjacent element combination, or / and the first L elements overlap with the last N / 2 elements in the previous adjacent element combination. This enhances the ability to capture tiny defects. Similarly, the element combinations and overlaps in all element combinations can be known.

[0055] At this point, taking the second array element combination as an example, the full matrix capture mode is used to scan the cable lead seal to capture the echo signal for all array element combinations, as follows:

[0056] The last N / 2 elements in the second element combination overlap with the first N / 2 elements in the adjacent third element combination, and the first N / 2 elements overlap with the last N / 2 elements in the adjacent first element combination.

[0057] In the second array element combination mode, N array elements are used as transmitting array elements in turn, and the transmitting frequency is f c The ultrasonic pulse is generated, and each time all the remaining array elements except the transmitting array element are used as receiving array elements; thus, N transmitting-receiving combinations can be obtained. In this case, each of the N transmitting-receiving combinations includes a transmitting array element and its corresponding (N-1) receiving array elements.

[0058] Secondly, when the one-dimensional ultrasonic array scans the cable sealing lead in sequence according to the above-mentioned preset multiple array element combinations and in full-matrix capture mode, the transmitting array elements and receiving array elements enabled each time in each array element combination are obtained, as well as the echo signal received by each receiving array element and the sound wave transmission time.

[0059] In one example, the N transmit-receive combinations in any element combination can directly determine the active transmit and receive elements at each time. Furthermore, after the scan is complete, the number of echo signals obtained for each element combination is the same: (N-1)*(N-1). Furthermore, the time at which the transmit element is activated at each time is defined as the acoustic start time, the initial time of the echo signal received by the corresponding receive element is defined as the acoustic end time, and the difference between the two times is defined as the acoustic transit time.

[0060] Finally, a global coordinate system is constructed based on the initial position of the one-dimensional ultrasonic array. Based on the preset spacing d between the array elements in the one-dimensional ultrasonic array, the positions of each transmitting unit and its corresponding receiving unit in each array element combination in the global coordinate system are obtained. It should be noted that by using simulation software to construct a three-dimensional model of the one-dimensional ultrasonic array and a three-dimensional model of the cable seal based on the global coordinate system, the position coordinates of each array element in the global coordinate system can be quickly obtained, thereby determining the positions of each transmitting unit and its corresponding receiving unit in each array element combination in the global coordinate system.

[0061] Step S2: Using a total focusing algorithm, phase compensation and signal superposition are performed on all echo signals obtained in each array element combination. Combined with the positions of each transmitting unit and its corresponding receiving unit in each array element combination in the global coordinate system, a three-dimensional signal intensity distribution image is generated based on each array element combination scanning the cable seal.

[0062] The specific process is as follows: first, obtain the echo signal s obtained by scanning the cable sealing lead based on each array element combination mode. ik (t); wherein, i is the transmitting unit index, and i=1, 2, ..., N; k is the receiving unit index, and j=1, 2, ..., N-1; t is the time variable.

[0063] Secondly, determine each echo signal s ik (t) Compensated phase time t i,k (r); where and d i (r)=||rr i ||, d k (r)=||rr k ||; c is the predetermined sound velocity of ultrasound in the cable seal; d i (r) is the distance of the acoustic wave transmission path from the transmitting unit i to the imaging point r; d k (r) is the distance of the acoustic wave transmission path from the reflected echo of the imaging point r to the receiving unit k; r i and r k are the positions of the transmitting unit i and the receiving unit k in the global coordinate system respectively; ||·|| is the Euclidean norm. It should be noted that the surface of the three-dimensional model of the cable sealing lead can be divided into a finite element model, and each grid is used as an imaging point to quickly map the position of the imaging point r in the global coordinate system, and then d can be obtained according to the coordinate conversion. i (r) and d k (r), the specific conversion process is a common technical means in this field and will not be repeated here.

[0064] Finally, each echo signal sik (t) at the corresponding compensation phase time t i,k The amplitude at (r) is coherently superimposed to generate a three-dimensional signal intensity distribution image I based on each array element combination scanning cable sealing lead. j (r); where

[0065] It should be noted that if there is a defect at the imaging point r, the sound wave will be scattered there and the signal will be i,k The signal at (r) will be enhanced due to the consistent phase, while the noise will cancel each other out due to the random phase.

[0066] Step S3: selecting defect signals that meet predetermined intensity matching conditions in each signal intensity distribution image, and determining each defect point and its position on the global coordinate system based on the position overlap of the defect signals in each signal intensity distribution image; wherein the position overlap of the defect signals includes the overlapping defect signals and the associated signal intensity distribution images;

[0067] The specific process is as follows: First, in each signal intensity distribution image, echo signals with a predetermined intensity matching condition (signal intensity greater than a predetermined intensity threshold) are selected as defect signals. Of course, other conditions can also be set to filter defect signals, for example, selecting the top three echo signals by signal intensity as defect signals.

[0068] Secondly, the positions of the transmitting and receiving array elements corresponding to each defect signal in the global coordinate system are found. Combined with the acoustic wave propagation time of each defect signal, the positions of the defect points generating the defect signal in the global coordinate system are simulated through conversion, and the overlap of the defect signal positions is further determined. The overlap of the defect signal positions includes the overlapping defect signals and the associated signal intensity distribution images.

[0069] For example, by the formula Get the position (x, y, z) of the defect point of the defect signal in the global coordinate system; where t ik It is the acoustic wave transmission time of the defect signal; (x i ,y i ,z i ) is the position of the transmitting element i in the global coordinate system, that is, r i ;(x k ,y k ,z k ) is the position of the receiving unit k in the global coordinate system, that is, r k .

[0070] The positions (x, y, z) of the defect signals in the global coordinate system are grouped and compared. If the positions (x, y, z) of multiple defect signals in the global coordinate system fall within a predetermined first range, these defect signals are considered to have overlapping positions and are generated by the same defect point, and the signal intensity distribution images of these defect signals are further found. If the positions (x, y, z) of multiple other defect signals in the global coordinate system fall within a predetermined second range, these defect signals are considered to have overlapping positions and are generated by the same defect point, and the signal intensity distribution images of these defect signals are further found. This process is repeated in this way until the positions of all defect signals overlap. It should be noted that the remaining defect signals without any overlapping positions will be deleted and will not be considered as defect signals generated by the defect point.

[0071] Finally, all defect signals that overlap at the same position are identified as echo signals of the same defect point, and a position in the global coordinate system is selected from all defect signals that overlap at the same position to output the position of the corresponding defect point in the global coordinate system, that is, one defect signal generated by the same defect point is randomly selected, and the position corresponding to the selected defect signal is output as the position of the defect point.

[0072] Step S4: constructing a vector coordinate system, and after registering each of the signal intensity distribution images with the vector coordinate system, determining the vector length and direction of each defect signal in each of the signal intensity distribution images; wherein the vector length of each defect signal is used to indicate the intensity of the signal, and the vector direction is used to indicate the direction of the signal toward the vector origin;

[0073] The specific process is as follows: first, construct a vector coordinate system.

[0074] Secondly, each signal intensity distribution image is aligned in the vector coordinate system, and the center point of each signal intensity distribution image is made to coincide with the vector origin on the vector coordinate system, and the vector length and direction of each defect signal in each signal intensity distribution image are further obtained; wherein the vector length of each defect signal is used to indicate the intensity of the signal, and the vector direction is used to indicate the direction of the signal pointing to the vector origin.

[0075] For example, when defining the properties of a vector field, the magnitude of the vector is directly taken from the intensity value of the signal intensity distribution image (TFM image), that is:

[0076] |V j (r)|=I j (r)

[0077] The direction of the vector is from the imaging point r to the center C j , that is, the unit direction vector is

[0078]

[0079] Step S5: Based on the vector length, vector direction, and position overlap of each defect signal in each signal intensity distribution image, unified vector calculation is performed on the defect signals that overlap at the same position to obtain the defect type of each defect point; wherein the defect types include cracks and holes; if the vector length after the unified vector calculation of the defect signals that overlap at the same position is greater than any vector length before the calculation, the obtained defect type is a crack; if the vector length after the unified vector calculation of the defect signals that overlap at the same position is less than any vector length before the calculation, the obtained defect type is a hole;

[0080] The specific process is as follows: first, according to the vector length, vector direction and position overlap of each defect signal in each signal intensity distribution image, the vector length and direction of the defect signal that overlaps at the same position contained in each defect point are selected for unified vector calculation.

[0081] It should be noted that signal vector calculation is a conventional technical means in this field and will not be described in detail here. Of course, different weights can be assigned to different signals before vector calculation. The specific situation can be flexibly designed according to actual conditions and will not be described in detail here.

[0082] Secondly, if the vector length of the defect signals of a certain defect point that coincide with each other at the same position after unified vector calculation is greater than any vector length before calculation, then the defect type of the defect point is a crack; conversely, if the vector length of the defect signals of a certain defect point that coincide with each other at the same position after unified vector calculation is less than any vector length before calculation, then the defect type of the defect point is a hole.

[0083] Step S6: Based on the actual physical structure of the cable seal, a three-dimensional model of the cable seal is simulated on the global coordinate system, and each defect point is automatically located and marked on the three-dimensional model of the cable seal according to its position on the global coordinate system and its defect type.

[0084] The specific process is as follows: first, according to the actual physical structure of the cable seal, simulation software is used to simulate a three-dimensional model of the cable seal in the global coordinate system.

[0085] Finally, according to the position of each defect point in the global coordinate system and its defect type, it is automatically located and marked on the three-dimensional model of the cable lead seal.

[0086] like Figure 2 FIG. 1 shows a cable seal internal defect location system based on vector full focusing in an embodiment of the present invention, comprising:

[0087] The scanning and full-matrix capture unit 110 is used to obtain the transmitting array elements and receiving array elements enabled each time in each array element combination mode, and obtain the echo signal and sound wave transmission time received by each receiving array element, and further obtain the position of each transmitting unit and its corresponding receiving unit in each array element combination mode on a preset global coordinate system; wherein each array element combination mode is obtained by extracting an equal number of array elements from the one-dimensional ultrasonic array and combining them, and There is some overlap between the array elements of the adjacent array element combination. The full-matrix capture mode is a method for traversing the preset transmit-receive combinations in each array element combination according to the excitation order predetermined in each array element combination to excite and receive ultrasound. The transmit-receive combinations in each array element combination are indexed by each array element as a transmit array element, and are composed of a one-to-many mapping between each transmit array element and all other array elements in the same array element combination except itself as receive array elements. The number of receive array elements in each transmit-receive combination is the same.

[0088] The TFM imaging data processing unit 120 is configured to perform phase compensation and signal superposition on all echo signals acquired in each array element combination using a total focusing algorithm, and generate a three-dimensional signal intensity distribution image based on each array element combination scanning the cable seal according to the position of each transmitting unit and its corresponding receiving unit in the global coordinate system;

[0089] The TFM image defect point screening unit 130 is configured to select defect signals that meet a predetermined intensity matching condition in each signal intensity distribution image, and determine each defect point and its position on the global coordinate system based on the position overlap of the defect signals in each signal intensity distribution image; wherein the position overlap of the defect signals includes the overlapping defect signals and the associated signal intensity distribution images;

[0090] The defect point vector registration unit 140 is configured to construct a vector coordinate system, and after registering each of the signal intensity distribution images with the vector coordinate system, determine the vector length and direction of each defect signal in each of the signal intensity distribution images; wherein the vector length of each defect signal indicates the signal intensity, and the vector direction indicates the direction of the signal toward the vector origin;

[0091] The defect point vector calculation unit 150 is configured to perform unified vector calculation on the defect signals that overlap at the same position based on the vector length, vector direction, and position overlap of each defect signal in each signal intensity distribution image, so as to obtain the defect type of each defect point; wherein the defect types include cracks and holes; if the vector length after the unified vector calculation of the defect signals that overlap at the same position is greater than any vector length before the calculation, the obtained defect type is a crack; if the vector length after the unified vector calculation of the defect signals that overlap at the same position is less than any vector length before the calculation, the obtained defect type is a hole;

[0092] The defect positioning and marking unit 160 is used to simulate a three-dimensional model of the cable seal on the global coordinate system based on the actual physical structure of the cable seal, and automatically locate and mark each defect point on the three-dimensional model of the cable seal according to its position on the global coordinate system and its defect type.

[0093] The implementation of the embodiments of the present invention has the following beneficial effects:

[0094] 1. The present invention uses a one-dimensional ultrasonic array with partially overlapping elements and adopts a full-matrix capture mode to sequentially scan the cable lead seal to generate high-resolution total focusing function (TFM) images, thereby enhancing the ability to capture tiny defects. This solves the problems commonly encountered in existing methods, such as high missed detection rates for tiny defects and poor adaptability to complex structures.

[0095] 2. The present invention preliminarily realizes the extraction of spatial orientation characteristics of defect points by extracting the vector size and direction of overlapping defect signals at the same position, effectively improving the problem of missing directional information of tiny defects, and adopts unified vector calculation to obtain the defect type of each defect point, so that the morphology and directional characteristics of different types of defects can be clearly presented, thereby solving the problems of missing directional information and poor adaptability to complex structures that are common in existing methods.

[0096] It is worth noting that in the above system embodiment, the various system modules included are only divided according to functional logic, but are not limited to the above division, as long as the corresponding functions can be achieved; in addition, the specific names of the various functional modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of the present invention.

[0097] Those skilled in the art will understand that all or part of the steps in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a program, and the program can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc.

[0098] The above disclosure is merely a preferred embodiment of the present invention and certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for locating internal defects of cable seals based on vector full focusing, characterized by: The method comprises the following steps: S1. When a one-dimensional ultrasonic array sequentially scans the cable sealing lead according to multiple predetermined array element combinations and in a full-matrix capture mode, the transmitting array elements and receiving array elements activated each time in each array element combination are obtained, as well as the echo signal and sound wave transmission time received by each receiving array element, and the position of each transmitting unit and its corresponding receiving unit in each array element combination in a preset global coordinate system is further obtained; wherein each array element combination is obtained by extracting an equal number of array elements from the one-dimensional ultrasonic array and combining them, and there is some overlap between the array elements of the adjacent array element combination; the full-matrix capture mode is a method for traversing the preset transmitting-receiving combinations in each array element combination according to the excitation order predetermined in each array element combination to excite and receive ultrasound; the transmitting-receiving combinations in each array element combination are indexed by each array element as a transmitting array element, and are composed of a one-to-many mapping between each transmitting array element and all other array elements in the same array element combination except itself as receiving array elements; the number of receiving array elements in each transmitting-receiving combination is the same; S2. Using a total focusing algorithm, perform phase compensation and signal superposition on all echo signals obtained in each array element combination, and combine the positions of each transmitting unit and its corresponding receiving unit in each array element combination in the global coordinate system to generate a three-dimensional signal intensity distribution image based on each array element combination scanning the cable seal. S3. Selecting defect signals that meet predetermined intensity matching conditions in each signal intensity distribution image, and determining each defect point and its position on the global coordinate system based on the position overlap of the defect signals in each signal intensity distribution image; wherein the position overlap of the defect signals includes the overlapping defect signals and the associated signal intensity distribution images; S4. Constructing a vector coordinate system, and after registering each of the signal intensity distribution images with the vector coordinate system, determining the vector length and direction of each defect signal in each of the signal intensity distribution images; wherein the vector length of each defect signal indicates the intensity of the signal, and the vector direction indicates the direction of the signal toward the vector origin; S5. Based on the vector length, vector direction, and position overlap of each defect signal in each signal intensity distribution image, perform unified vector calculation on the defect signals that overlap at the same position to obtain the defect type of each defect point; wherein the defect types include cracks and holes; if the vector length after the unified vector calculation of the defect signals that overlap at the same position is greater than any vector length before the calculation, the obtained defect type is a crack; if the vector length after the unified vector calculation of the defect signals that overlap at the same position is less than any vector length before the calculation, the obtained defect type is a hole; S6. Based on the actual physical structure of the cable seal, a three-dimensional model of the cable seal is simulated on the global coordinate system, and each defect point is automatically located and marked on the three-dimensional model of the cable seal according to its position and defect type on the global coordinate system.

2. The method for locating internal defects of cable seals based on vector total focusing according to claim 1 is characterized in that: The step S1 specifically includes: Determine a plurality of predefined array element combinations of a one-dimensional ultrasonic array and their corresponding full-matrix capture modes; wherein each array element combination is obtained by extracting an equal number of array elements from the one-dimensional ultrasonic array and combining them, and there is partial overlap of array elements between adjacent array element combinations; the full-matrix capture mode is a mode for traversing the preset transmit-receive combinations in each array element combination according to the excitation sequence predetermined in each array element combination to perform ultrasonic excitation and reception; the transmit-receive combinations in each array element combination are indexed by each array element as a transmit array element, and are composed of a one-to-many mapping of each transmit array element with all other array elements in the same array element combination except itself as receive array elements; the number of receive array elements in each transmit-receive combination is the same; When the one-dimensional ultrasonic array sequentially scans the cable sealing lead according to multiple array element combinations and in a full matrix capture mode, the transmitting array element and the receiving array element activated each time in each array element combination are obtained, and the echo signal received by each receiving array element and the sound wave transmission time are obtained; Based on the initial position of the one-dimensional ultrasonic array, a global coordinate system is constructed, and according to the preset spacing between the array elements in the one-dimensional ultrasonic array, the position of each transmitting unit and its corresponding receiving unit in each array element combination in the global coordinate system is obtained.

3. The method for locating internal defects of cable seals based on vector total focusing according to claim 1 is characterized in that: The step S2 specifically includes: Acquire the echo signal s obtained by scanning the cable sealing lead based on each array element combination mode ik (t); where i is the transmitting unit index, and i=1, 2, ..., N; k is the receiving unit index, and j=1, 2, ..., N-1; t is the time variable; Determine each echo signal s ik (t) Compensated phase time t i,k (r); where and d i (r)=||rr i ||, d k (r)=||rr k ||; c is the predetermined sound velocity of ultrasound in the cable seal; d i (r) is the distance of the acoustic wave transmission path from the transmitting unit i to the imaging point r; d k (r) is the distance of the acoustic wave transmission path from the reflected echo of the imaging point r to the receiving unit k; r i and r k are the positions of the transmitting unit i and the receiving unit k in the global coordinate system respectively; ||·|| is the Euclidean norm; Each echo signal s ik (t) at the corresponding compensation phase time t i,k The amplitudes at (r) are coherently superimposed to generate a three-dimensional signal intensity distribution image I obtained by scanning the cable sealing lead in each array element combination mode. j (r); where N is the total number of array elements in any array element combination, which is a positive even number.

4. The method for locating internal defects of cable seals based on vector total focusing according to claim 3 is characterized in that: The step S3 specifically includes: In each signal intensity distribution image, an echo signal having a predetermined intensity matching condition and a signal intensity greater than a predetermined intensity threshold is selected as a defect signal; Based on the positions of the transmitting unit and the receiving unit corresponding to each defect signal in the global coordinate system and the acoustic wave transmission time of each defect signal, the position of the defect point generating the defect signal in the global coordinate system is simulated, and the position overlap of the defect signals is further determined; wherein the position overlap of the defect signals includes the overlapping defect signals and the associated signal intensity distribution images; All defect signals overlapping at the same position are identified as echo signals of the same defect point, and a position on the global coordinate system is selected from all defect signals overlapping at the same position to output the position of the corresponding defect point on the global coordinate system.

5. The method for locating internal defects of cable seals based on vector total focusing according to claim 4 is characterized in that: The step S4 specifically includes: Construct a vector coordinate system; Each of the signal intensity distribution images is aligned in the vector coordinate system, and the center point of each of the signal intensity distribution images is made to coincide with the vector origin on the vector coordinate system, and the vector length and direction of each defect signal in each of the signal intensity distribution images are further obtained; wherein the vector length of each defect signal is used to indicate the intensity of the signal, and the vector direction is used to indicate the direction of the signal pointing to the vector origin.

6. The method for locating internal defects of cable seals based on vector total focusing according to claim 5 is characterized in that: The step S5 specifically includes: According to the vector length, vector direction and position overlap of each defect signal in each signal intensity distribution image, the vector length and direction of the defect signal that overlaps at the same position contained in each defect point are selected to perform unified vector calculation; If the length of the vector after unified vector calculation of the overlapping defect signals at the same position contained in a certain defect point is greater than any vector length before calculation, then the defect type of the defect point is obtained as a crack; If the length of the vector after unified vector calculation of the overlapping defect signals at the same position contained in a certain defect point is less than any vector length before calculation, the defect type of the defect point is obtained as a hole.

7. The method for locating internal defects of cable seals based on vector total focusing according to claim 6, characterized in that: The step S6 specifically includes: According to the actual physical structure of the cable seal, a three-dimensional model of the cable seal is simulated in the global coordinate system using simulation software; According to the position of each defect point on the global coordinate system and the defect type, automatic positioning and marking are performed on the three-dimensional model of the cable lead seal.

8. A cable seal internal defect location system based on vector full focusing, characterized by: include: The scanning and full-matrix capture unit is used to obtain the transmitting array elements and receiving array elements enabled each time in each array element combination mode, and obtain the echo signal and sound wave transmission time received by each receiving array element, and further obtain the position of each transmitting unit and its corresponding receiving unit in each array element combination mode on a preset global coordinate system; wherein, each array element combination mode is obtained by extracting an equal number of array elements from the one-dimensional ultrasonic array and combining them, and its Adjacent array element combinations have some overlapping array elements. The full-matrix capture mode is a method for traversing the preset transmit-receive combinations in each array element combination according to the excitation sequence predetermined in each array element combination to excite and receive ultrasound waves. The transmit-receive combinations in each array element combination are indexed by each array element as a transmit array element, and are composed of a one-to-many mapping between each transmit array element and all other array elements in the same array element combination except itself as receive array elements. The number of receive array elements in each transmit-receive combination is the same. a TFM imaging data processing unit, configured to perform phase compensation and signal superposition on all echo signals acquired in each array element combination using a total focusing algorithm, and generate a three-dimensional signal intensity distribution image based on scanning of the cable seal by each array element combination in combination with the positions of each transmitting unit and its corresponding receiving unit in the global coordinate system; The TFM image defect point screening unit is used to select defect signals that meet the predetermined intensity matching conditions in each signal intensity distribution image, and determine each defect point and its position on the global coordinate system based on the position overlap of the defect signals in each signal intensity distribution image; wherein the position overlap of the defect signals includes the overlapping defect signals and the associated signal intensity distribution images; a defect point vector registration unit, configured to construct a vector coordinate system, and after registering each of the signal intensity distribution images with the vector coordinate system, determine the vector length and direction of each defect signal in each of the signal intensity distribution images; wherein the vector length of each defect signal indicates the intensity of the signal, and the vector direction indicates the direction of the signal toward the vector origin; a defect point vector calculation unit, configured to perform unified vector calculation on the defect signals overlapping at the same position based on the vector length, vector direction, and position overlap of each defect signal in each signal intensity distribution image, to obtain a defect type for each defect point; wherein the defect types include cracks and holes; if the vector length after the unified vector calculation of the defect signals overlapping at the same position is greater than any vector length before the calculation, the obtained defect type is a crack; if the vector length after the unified vector calculation of the defect signals overlapping at the same position is less than any vector length before the calculation, the obtained defect type is a hole; The defect positioning and marking unit is used to simulate a three-dimensional model of the cable seal on the global coordinate system according to the actual physical structure of the cable seal, and automatically locate and mark each defect point on the three-dimensional model of the cable seal according to the position of each defect point on the global coordinate system and the defect type.

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