Double-layer medium ultrasonic imaging method and related device based on tool center coordinates of one-shot and multiple-receiver wavefront trajectory common tangent point

Abstract

The present invention discloses a double-layer medium ultrasonic imaging method and related device based on the common tangent point of the wavefront trajectory of the tool center coordinate, belonging to the field of ultrasonic non-destructive testing technology. A workpiece coordinate system is established with a certain point on the workpiece as the coordinate origin, and a linear phased array probe is clamped by a multi-axis scanning system. Based on the tool center coordinates returned at each scanning position, the position and deflection angle of each array element at this scanning position relative to the coordinate origin are inverted; multiple groups of single-shot multiple-receiver ultrasonic echo signals in the full matrix data collected at this scanning position are used to establish several common tangent points between the wavefront trajectory and the curved workpiece, and then the workpiece surface contour line is constructed through interpolation processing; the workpiece surface contour line measured by the wavefront trajectory common tangent point method, the array element position under the tool center coordinates, and the single-shot multiple-receiver mode signal are used to construct an ultrasonic image of the curved workpiece through a double-layer medium delay superposition algorithm, thereby realizing ultrasonic imaging of complex curved surface workpieces under water immersion automated phased array testing conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of ultrasonic non-destructive testing, and in particular relates to a double-layer medium ultrasonic imaging method and related devices based on a common tangent point of a one-shot-multiple-receiver wavefront trajectory of a tool center coordinate. Background Art

[0002] Nondestructive testing (NDT) plays a crucial role in industrial production, ensuring that target workpieces or equipment are free of defects during manufacturing and use, thereby guaranteeing their quality and reliability. Currently, common NDT methods include ultrasonic testing (UT), radiographic testing (RT), magnetic particle testing (MT), and penetrant testing (PT), with UT playing a key role. Existing automated ultrasonic testing technology primarily utilizes water immersion ultrasonic testing, which is suitable for structures such as plates and bars with simple surface regularities. Existing algorithms are capable of rapid, real-time processing of dual-layer media imaging, where a simple, known, and unchanging interface is formed between a plate, bar, and water.

[0003] In recent years, the demand for automated ultrasonic testing of large, complex curved workpieces has increased and become a new trend. When using water immersion ultrasonic testing methods to inspect large, complex curved workpieces, the large, complex curved workpiece and water will form a double-layer medium imaging of a complex, unknown, and changing interface. Existing water immersion ultrasonic testing methods for simple rod and plate structures are unable to cope with double-layer medium imaging of complex, unknown, and changing interfaces. In addition, most existing research uses single-layer medium imaging, and then extracts the interface of the double-layer medium imaging from the single-layer medium imaging, converting the unknown interface imaging into a known interface imaging. However, this method takes a long time to extract the interface and has low interface accuracy. Therefore, in the automated ultrasonic testing of large, complex curved workpieces, quickly extracting unknown interfaces with high precision remains a challenge. Summary of the Invention

[0004] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a double-layer medium ultrasonic imaging method and related devices based on the common tangent point of the wavefront trajectory of one transmission and multiple reception based on the tool center coordinates, so as to solve the technical problem that the existing double-layer medium imaging method cannot quickly and accurately reconstruct the large-scale complex interface shape of the probe.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A first aspect of the present invention discloses a method for double-layer medium ultrasonic imaging based on a common tangent point of a single-shot and multiple-receiver wavefront trajectory based on tool center coordinates, comprising the following steps:

[0007] Acquire ultrasonic data and position information of array probe elements in the workpiece coordinate system;

[0008] A one-shot-multiple-receiver mode signal is obtained at the position information of the array probe element. The sound propagation distance corresponding to the maximum echo in the ultrasonic echo signal is obtained based on the one-shot-multiple-receiver mode signal, and the corresponding wavefront trajectory tangent point is constructed. The surface contour line of the large complex curved surface workpiece is constructed through the wavefront trajectory tangent point;

[0009] According to the surface contour of large and complex curved workpieces, the array element position under the tool center coordinates and the acquired one-transmit-multiple-receive mode signal, the ultrasonic image of large and complex curved workpieces is constructed through the double-layer medium delay superposition algorithm.

[0010] Preferably, the specific steps of obtaining ultrasonic data and position information of array probe elements in the workpiece coordinate system are as follows: scanning and detecting large complex curved workpieces by the probe of the water immersion ultrasonic system, collecting ultrasonic data and position information of array probe elements in the workpiece coordinate system at each scanning position, and calculating the position information of the array probe elements in the workpiece coordinate system according to the center distance between two adjacent elements. d , Number of phased array probe elements N As well as the position information of the array probe elements in the workpiece coordinate system, the coordinate positions of any transmitting array element and any receiving array element are obtained.

[0011] Further preferably, the ultrasound data is full matrix data {S11, S12...S ij …S NN}, the position information is the tool center coordinates (x0, y0, z0) of the scan position and the probe-horizontal deflection angle θ;

[0012] in, i and j are the transmitting element number and the receiving element number respectively, i= 1,2… N , j= 1,2… N , N is the number of probe elements.

[0013] Further preferably, the coordinate position of any transmitting array element is T i ( T xi , T yi , T zi ):

[0014]

[0015] The coordinate position of any receiving array element is:

[0016]

[0017] Where, Txi For any transmitting array element i The x-axis coordinate, T yi For any transmitting array element i The y-axis coordinate of T zi For any transmitting array element i The z-axis coordinate of R xj For any receiving array element j The x-axis coordinate, R yj For any receiving array element j The y-axis coordinate of R zj For any receiving array element j The z-axis coordinate of i For any transmitting array element, 1≤ i ≤ N , j For any receiving array element, 1≤ j ≤ N , the value range of θ is [-90°, 90°].

[0018] Preferably, the specific steps of constructing the surface contour line of a large complex curved workpiece from the position information of the array probe elements are as follows: first, extracting the sound propagation distance of the maximum echo of each transmitting-receiving array element from the ultrasonic data, and obtaining the propagation distance of the sound wave from the transmitting array element to the common tangent point of the wavefront trajectory and then to the receiving array element; second, combining the position information of the array probe elements in the workpiece coordinate system and the propagation distance of the sound wave from the transmitting array element to the common tangent point of the wavefront trajectory and then to the receiving array element, obtain multiple common tangent points of the wavefront trajectory that characterize the surface contour line of the large complex curved workpiece; finally, reconstructing the surface contour line of the large complex curved workpiece by interpolating the common tangent points of the wavefront trajectory.

[0019] Further preferably, the propagation distance of the sound wave from the transmitting array element to the common tangent point of the wavefront trajectory and then to the receiving array element is obtained by dividing the ultrasonic data into N A data set of one-transmit-multiple-receive mode signals is formed, and formulas (3) and (4) are used to calculate the N The transmitting array element number and the receiving array element number are selected from the signal data set of the one-transmit-multiple-receive mode to form k A set of one-transmit-multiple-receive signal data sets, each of which contains m Signals:

[0020] (3)

[0021] (4)

[0022] Where, i andj are the transmitting element number and the receiving element number respectively, i =1,2… N , j =1,2… N , N is the number of probe elements; k To select the number of transmission groups, k < N ; g is the transmission interval of the array element, m for k The number of receiving array elements selected for each data set in the group data set;

[0023] for k For any group of one-transmit-multiple-receive mode signals in the one-transmit-multiple-receive mode signal data set, according to the transmitting array element sequence number and the receiving array element sequence number, combined with the coordinate position of the transmitting array element and the coordinate position of the receiving array element, the sound propagation distance of the sound waves emitted by all the array elements in the group to the workpiece surface and back is calculated according to formula (5):

[0024] (5)

[0025] Where, T i Q For both the transmitted and received signals i The sound propagation distance when R j V + T i V The transmitting array element is i , the receiving array element is j The sound propagation distance when t ii For both transmitting and receiving signals i The sound propagation time corresponding to the maximum echo is t ij The transmitting array element is i , the receiving array element is j The sound propagation time corresponding to the maximum echo is i ≠ j , c 1 is the sound velocity of the first medium.

[0026] Further preferably, the common tangent point of the wavefront trajectory is obtained by constructing a similar triangle using the coordinate position of the transmitting array element, the coordinate position of the receiving array element, and the propagation distance of the sound wave from the transmitting array element to the common tangent point of the wavefront trajectory and then to the receiving array element, and using trigonometric functions, Heron's formula and the Pythagorean theorem to calculate the coordinates of the common tangent point of the wavefront trajectory, thereby obtaining all the common tangent points of the wavefront trajectory corresponding to the one-transmit-multiple-receive mode signal that represent the surface contour line of the large complex curved workpiece.

[0027] Further preferably, after obtaining the coordinates of the common tangent point of the wavefront trajectory, loop m receiving array elements, and we can obtain k The common tangent points of all wavefront trajectories corresponding to any group of one-transmit-multiple-receive mode signals in the one-transmit-multiple-receive mode signal data set, excluding the common tangent points of the wavefront trajectories obtained when the transmitting array element and the receiving array element are the same, are calculated in total. m -1 common tangent point of wavefront trajectory; further calculation k All the common tangent points of the wavefront trajectories corresponding to the one-transmit-multiple-receive mode signals are grouped, and the common tangent points of the wavefront trajectories obtained when the transmitting array elements and the receiving array elements are the same are removed, so as to obtain all the common tangent points of the wavefront trajectories corresponding to the one-transmit-multiple-receive mode signals representing the surface contour lines of large complex curved workpieces.

[0028] Preferably, the steps of constructing an ultrasonic image of a large complex curved surface workpiece based on the surface contour line of the large complex curved surface workpiece, the array element position at the tool center coordinates and the acquired one-shot-multiple-receiver mode signal through a double-layer medium delay superposition algorithm are as follows: using the horizontal range of the reconstructed surface contour line of the large complex curved surface workpiece to determine the horizontal range of the imaging area, and determining the vertical range of the imaging area based on the detection water path and the thickness of the surface of the large complex curved surface workpiece; combining the surface contour line of the large complex curved surface workpiece, the array element position at the tool center coordinates at the scanning position and the acquired one-shot-multiple-receiver mode signal, to construct an ultrasonic image of the large complex curved surface workpiece through a double-layer medium delay superposition algorithm.

[0029] A second aspect of the present invention discloses a double-layer medium ultrasonic imaging system with a common tangent point of wavefront trajectories based on tool center coordinates, comprising:

[0030] Position information acquisition module, used to obtain ultrasonic data and position information of array probe elements in the workpiece coordinate system;

[0031] A surface contour line construction module is used to obtain a multi-receiver mode signal at the position information of the array probe element, obtain the sound propagation distance corresponding to the maximum echo in the ultrasonic echo signal based on the multi-receiver mode signal, construct the corresponding wavefront trajectory tangent point, and construct the surface contour line of large and complex curved surface workpieces through the wavefront trajectory tangent point;

[0032] The imaging module is used to construct an ultrasonic image of a large and complex curved workpiece through a double-layer medium delay superposition algorithm based on the surface contour of the workpiece, the array element position under the tool center coordinates, and the acquired one-transmit-multiple-receive mode signal.

[0033] The third aspect of the present invention discloses a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the above-mentioned method for ultrasonic imaging of a double-layer medium with a common tangent point of a single-transmitter and multiple-receiver wavefront trajectory based on the tool center coordinates are implemented.

[0034] In a fourth aspect of the present invention, a computer-readable storage medium is disclosed, which stores a computer program. When the computer program is executed by a processor, it implements the steps of the above-mentioned double-layer medium ultrasonic imaging method with a common tangent point of the wavefront trajectory of one transmission and multiple reception based on the tool center coordinate.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The present invention provides a double-layer medium ultrasonic imaging method based on tool center coordinates using a multi-shot, multi-receiver wavefront trajectory common tangent point. First, a multi-axis scanning system and array probe in an immersion ultrasonic system are used to acquire ultrasonic data and the position information of the array probe elements in the workpiece coordinate system. In this step, the acquired ultrasonic data can be used to characterize the shape of the water-workpiece interface, and the acquired position information can be used to reconstruct large, complex interfaces. Second, a multi-shot, multi-receiver mode signal is acquired at the position information of the array probe elements. Based on the multi-shot, multi-receiver mode signal, the acoustic propagation distance corresponding to the maximum echo in the ultrasonic echo signal is obtained, and the corresponding wavefront trajectory common tangent point is constructed. The surface contour of the large, complex curved workpiece is constructed using the wavefront trajectory common tangent point. In this step, the acquired multi-shot, multi-receiver mode signal can be used to extract the ultrasonic echo distance corresponding to the maximum echo representing the water-workpiece interface. The acoustic propagation distance corresponding to the maximum echo in the acquired ultrasonic echo signal can be used to calculate the wavefront trajectory common tangent point. Using a large number of wavefront trajectory common tangent points, the actual shape of the water-workpiece interface can be characterized. Finally, based on the surface contour of the large complex curved workpiece, the array element position at the tool center coordinates, and the acquired single-transmitter-multiple-receiver mode signal, an ultrasonic image of the large complex curved workpiece is constructed using a double-layer medium delay superposition algorithm, thereby revealing defects in the target workpiece and quickly reconstructing the interface facing the probe. In this step, the surface contour of the large complex curved workpiece and the acquired ultrasonic data enable ultrasonic imaging of the large complex curved workpiece. The acquired array element position at the tool center coordinates and the calculated ultrasonic image of the complex curved workpiece can reveal the actual location of the defect being inspected in the large complex interface. This method has fast operation speed, high characterization accuracy, low computational complexity, a wide range of applicability, and can be combined with intelligent equipment, showing good prospects for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Flowchart of the method for double-layer medium ultrasonic imaging based on the common tangent point of the tool center coordinates and the one-shot-multiple-receiver wavefront trajectory;

[0038] Figure 2 Schematic diagram of the calculation principle of the common tangent point of the one-shot-multiple-receiver wavefront trajectory based on the target tool center coordinates of the present invention;

[0039] Figure 3 is a schematic diagram of an immersion ultrasound system used in the present invention;

[0040] Figure 4 is a schematic diagram of a workpiece to be inspected according to the present invention;

[0041] Figure 5 This is a double-layer medium ultrasonic imaging diagram of the common tangent points of the one-shot-multiple-receiver wavefront trajectory based on the tool center coordinates at three positions in the same workpiece coordinate system of the present invention.

[0042] Among them: 1- multi-axis scanning system; 2- water tank; 3- inspected workpiece; 4- ultrasonic phased array probe; 5- signal acquisition system; 6- host; 7- display screen. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0044] It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the numbers used in this manner are interchangeable where appropriate so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or inherent to these processes, methods, products, or apparatus.

[0045] The present invention discloses a double-layer medium ultrasonic imaging method based on a tool center coordinate system with a common tangent point of wavefront trajectories. Figure 1 As shown, the following steps are included:

[0046] S1, obtaining ultrasonic data and position information of array probe elements in the workpiece coordinate system;

[0047] Preferably, a certain point on the target workpiece in the water immersion ultrasonic system is used as the coordinate origin to solve the coordinates of each array element of the probe;

[0048] S1.1. First, fix the target workpiece in the water tank of the immersion ultrasonic system. Second, establish the workpiece coordinate system xyz with a certain point of the target workpiece as the coordinate origin. Third, plan the scanning path through the immersion ultrasonic system and drive the multi-axis scanning system of the immersion ultrasonic system. The number of clamping array elements is N The linear phased array probe scans the target workpiece and collects full matrix data {S11, S12…S ij …S NN}( i and j are the transmitting and receiving array element numbers respectively, where i=1,2… N , j =1,2… N ), return the tool center coordinates (x0, y0, z0) and the probe-horizontal deflection angle θ at the scanning position, and solve the position and deflection angle θ of each array element relative to the coordinate origin at the scanning position;

[0049] S1.2, based on the center distance between two adjacent array elements d , Number of phased array probe elements N , S1.1 Establish the tool center coordinates (x0, y0, z0) and the probe-horizontal deflection angle θ in the coordinate system, and calculate the coordinate position of any transmitting array element i by combining formula (1) T i ( T xi , T yi , T zi ), combined with formula (2) to calculate any receiving array element j Coordinate location R j ( R xj , R yj , R zj );

[0050] Any transmitting element i The coordinates are:

[0051] (1)

[0052] Any receiving element j The coordinates are:

[0053] (2)

[0054] Where, T xi For any transmitting array element i The x-axis coordinate, T yi For any transmitting array element i The y-axis coordinate of T zi For any transmitting array element i The z-axis coordinate of R xj For any receiving array element j The x-axis coordinate, R yj For any receiving array element j The y-axis coordinate of R zjFor any receiving array element j The z-axis coordinate of i For any transmitting array element, 1≤ i ≤ N , j For any receiving array element, 1≤ j ≤ N , the value range of θ is [-90°, 90°];

[0055] S2: Acquire a multi-receiver mode signal at the position information of the array probe element, obtain the sound propagation distance corresponding to the maximum echo in the ultrasonic echo signal based on the multi-receiver mode signal, construct the corresponding wavefront trajectory tangent point, and construct the surface contour line of the large complex curved surface workpiece through the wavefront trajectory tangent point;

[0056] Preferably, the full matrix data {S11, S12...S ij …S NN}, constructing the wavefront trajectory common tangent point used to characterize the workpiece surface contour line, and then reconstructing the workpiece surface contour line through the wavefront trajectory common tangent point;

[0057] S2.1, in the one-transmit-multiple-receive mode, the transmitting and receiving array elements of the probe are regarded as the two foci of an ellipse, and the motion trajectory of the ultrasonic wavefront is approximately an ellipse. ij …S NN}divided into N A data set of signals in a one-transmit-multiple-receive mode is denoted as {{S11…S1 j …S1 N}1…{S i 1…S ij …S iN} i …{S N 1…S Nj …S NN} N}, ( i and j are the transmitting and receiving array element numbers respectively, where i =1,2… N , j =1,2… N , which completely corresponds to the full matrix data number in S1), define k To select the number of transmission groups, g is the transmission interval of the array element, and then N Group data set selection k A data set of signals in a one-transmit-many-receive mode ( k < N ), the selected transmitting array element number refers to formula (3):

[0058] (3)

[0059] Assumptions k The number of receiving array elements selected for each data set in the group data set is m , then select the receiving sequence number of the signal according to formula (4):

[0060] (4)

[0061] After selecting the transmitting and receiving signals using formulas (3) and (4), we have k A set of one-transmit-multiple-receive signal data sets, each of which contains m A signal.

[0062] S2.2, for k Any group of one-transmit-multiple-receive mode signals in the group one-transmit-multiple-receive mode signal data set, according to the transmitting array element sequence number shown in S1 i and receiving element number j , combined with the coordinates of the transmitting array element and the receiving array element obtained by formulas (1) and (2) in S1.2, the sound propagation distance of the sound waves emitted by all the array elements in the group to the workpiece surface and back is calculated according to formula (5). Formula (5) is as follows:

[0063] (5)

[0064] Where, T i Q For both the transmitted and received signals i The sound propagation distance when R j V + T i V The transmitting array element is i , the receiving array element is j The sound propagation distance when t ii For both transmitting and receiving signals i The sound propagation time corresponding to the maximum echo is t ij The transmitting array element is i , the receiving array element is j ( i ≠ j ) corresponds to the sound propagation time of a maximum echo, c 1 is the sound velocity of the first medium.

[0065] S2.3, such as Figure 2 As shown, assuming that the interface normal is Q andV The slopes at can be considered to be approximately equal, then the line segment T i Q 、 R j V The extension lines intersect at point W ,triangle T i QV With triangle WQV congruent; line segments T i W The length of the line segment is twice T i Q Length, line segment T i V With line segment VW The lengths of the segments are equal, R j W The length of the line segment R j V With line segment VW Sum of lengths; line segments D ij is the distance between the transmitting array element and the receiving array element, and its length is d Integer multiples of T i WR j By using the cosine theorem, we can get α ij The specific calculation formula is:

[0066] (6)

[0067] S2.4, in triangle T i QV Through the line segment T i Q Length and α ij , we can get the line segment T i V The length of the line segment R j V length; V Point as the starting point to the line segment D ij Draw a perpendicular line that intersects the point F , in the triangle Ti VR j In the line segment T i V 、 R j V 、 D ij The length of the line segment and Heron's formula FV The length of the triangle T i VF Through the line segment T i V 、 FV Length and Pythagorean Theorem to solve line segments T i F The specific calculation formula is:

[0068] (7)

[0069] Where, l is a triangle T i VR j half of its circumference;

[0070] S2.5, over V Point to Point T i Draw a perpendicular line to the horizontal line at C , and line segments T i F Intersection point E ; In the triangle EFV Through the line segment FV Length, probe deflection angle θ and trigonometric function to solve line segments EF 、 EV Length; through line segment T i F Length of the line segment T i E The length of the triangle T i CE Through the line segment T i E Length and trigonometric functions to solve line segments T i C 、 CE and CV Length, the specific solution process is:

[0071] (8)

[0072] Finally, through the array element T i Coordinates and line segments CV 、 T i C Length solution common tangent point V The coordinates (x V ,y V , z V ); the specific solution process is:

[0073] (9)

[0074] S2.6, in any one of the k sets of one-transmit-multiple-receive mode signals in the data set, use equations (5)-(9) to solve the transmit array element i , receiving array element j The corresponding wavefront trajectory tangent point, cycle m receiving array elements, and we can obtain k The common tangent points of all wavefront trajectories corresponding to any group of one-transmit-multiple-receive mode signals in the one-transmit-multiple-receive mode signal data set, excluding the common tangent points of the wavefront trajectories obtained when the transmitting array element and the receiving array element are the same, are calculated in total. m -1 common tangent point of wavefront trajectory;

[0075] S2.7, using formulas (3)-(9), calculate k The common tangent points of all wavefront trajectories corresponding to the one-transmit-multiple-receive mode signal are calculated, excluding the common tangent points of the wavefront trajectories obtained when the transmitting array element and the receiving array element are the same. k ×( m -1) wavefront trajectory tangent point; finally k ×( m -1) wavefront trajectory common tangent points are interpolated to obtain the reconstructed target workpiece surface contour line.

[0076] S3, based on the surface contour of large complex curved workpieces, the array element position under the tool center coordinates and the acquired multi-receiver mode signal, constructs an ultrasonic image of the large complex curved workpiece through a double-layer medium delay superposition algorithm.

[0077] Preferably, the horizontal range of the target workpiece surface contour line reconstructed by S2 interpolation is used to determine the horizontal range of the imaging area, and the vertical range of the imaging area is determined according to the detection water range and the thickness of the target workpiece; the workpiece surface contour line measured by S2 is combined with the array element position under the tool center coordinates and the acquired one-transmit-multiple-receive mode signal, and the ultrasonic image of the curved workpiece is reconstructed through double-layer medium delay superposition, thereby realizing double-layer medium ultrasonic imaging of the measured scanning position of the target workpiece.

[0078] The following uses Figure 3 The water immersion ultrasonic system shown in the figure is used to detect Figure 4 The aluminum concave workpiece shown in the drawings is used to further illustrate the present invention. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0079] In the following examples, the water immersion ultrasonic system used is as follows Figure 3 As shown, the system comprises a multi-axis scanning system 1, a water tank 2, a linear ultrasonic phased array probe 4, an ultrasonic signal acquisition system 5, a host computer 6, and a display 7. The multi-axis scanning system 1 can hold the linear ultrasonic phased array probe 4 and immerse it in the water tank 2. The ultrasonic phased array probe 4 is a 5L64-0.6×10-10 type ultrasonic phased array probe with a center frequency fs = 5 MHz, 64 array elements, a center-to-center spacing of 0.6 mm, an element length of 10 mm, and an element width of 0.55 mm. The ultrasonic signal acquisition system 5 has two 32-channel ultrasonic transmit / receive interfaces on its panel. One end of the ultrasonic signal acquisition system 5 is connected to the linear ultrasonic phased array probe 4 via an adapter and the two 32-channel ultrasonic transmit / receive interfaces. The other end is connected to the host computer 6 and the display 7 in sequence.

[0080] In the following embodiments, an aluminum concave workpiece with three side drilling defects is used as the inspected workpiece 3. Figure 4 As shown in the figure, the aluminum concave workpiece with three edge drilling defects has a total of three edge drilling defects. The diameter of the leftmost edge drilling hole is 2 mm and the distance from the concave surface is 4 mm. The diameter of the middle edge drilling hole is 2 mm and the distance from the concave surface is 6 mm. The diameter of the rightmost edge drilling hole is 2 mm and the distance from the concave surface is 8 mm.

[0081] Example 1

[0082] Ultrasonic imaging of the workpiece 3 is performed using a double-layer medium ultrasonic imaging method with a common tangent point of the wavefront trajectory based on the tool center coordinate. The specific steps are as follows:

[0083] S1, taking a certain point on the target workpiece in the water immersion ultrasonic system as the coordinate origin, solve the coordinates of each element of the linear ultrasonic phased array probe

[0084] S1.1, first, in the Figure 3The water tank 2 of the water immersion ultrasonic system is filled with water, and then the workpiece 3 to be inspected is immersed in the water tank 2 and fixed using a clamping device. Figure 3 The experimental water immersion ultrasonic system is installed in the manner shown. The multi-axis scanning system 1 is controlled to move the linear ultrasonic phased array probe 4 to the top of three different defects of the workpiece 3 under inspection. The workpiece coordinate system xyz is established with the center of the leftmost linear ultrasonic phased array probe 4 as the coordinate origin, the horizontal direction as the x-axis, and the vertical direction as the z-axis. Next, the scanning path is planned by the water immersion ultrasonic system. The multi-axis scanning system 1 of the water immersion ultrasonic system is driven to clamp the linear ultrasonic phased array probe 4 with N array elements to scan the workpiece 3 under inspection. The full matrix data {S11, S12…S ij …S NN}( i and j are the transmitting and receiving array element numbers respectively, where i =1,2… N , j =1,2… N ), return the tool center coordinates (x0, y0, z0) of the scanning position and the probe-horizontal deflection angle θ, and solve the position and deflection angle θ of each array element at the scanning position relative to the coordinate origin. The tool center coordinates of the three defect scanning positions from left to right are: (0, 0, 0), (64.25, 0, 5.42), (124.39, 0, -2.97). Finally, in the workpiece coordinate system, the multi-axis scanning system 1 returns the tool center coordinates and inverts the position and deflection angle θ of each array element at the three scanning positions relative to the coordinate origin. The obtained deflection angles θ are: -13.01°, 2.82°, and 12.48° respectively;

[0085] S1.2, set the basic detection parameters in the system control program of display 7, such as sampling frequency fs = 62.5 MHz, the number of transmitting / receiving array elements is 64, the transmitting voltage is 15 V, and the signal acquisition mode is full matrix acquisition. After determining the acquisition parameters and acquisition mode, according to the center distance between two adjacent array elements, d , Number of phased array probe elements N , S1.1 Establish the tool center coordinates (x0, y0, z0) and the probe-horizontal deflection angle θ in the coordinate system, and calculate the coordinate position of any transmitting array element i by combining formula (1) T i ( T xi ，T yi , T zi ), combined with formula (2) to calculate the coordinate position of any receiving array element j R j ( Rxj ，R yj , R zj ), full matrix data collection is performed at three positions above the defect of the inspected workpiece 3.

[0086] S2, select the full matrix data {S11, S12…S ij …S NN}, construct the wavefront trajectory common tangent point used to characterize the surface contour line of the inspected workpiece 3, and then reconstruct the surface contour line of the inspected workpiece 3 through the wavefront trajectory common tangent point

[0087] S2.1, the full matrix data {S11, S12…S ij …S NN}divided into N A data set of signal from a transmitter-multiple receiver mode is formed, and then N Group data set selection k A data set of signals in a one-transmit-many-receive mode ( k < N ), the selected transmitting array element number refers to formula (3), the selected signal receiving number refers to formula (4), and in formulas (3) and (4) set k =10, g =6, m =9, that is, 10 groups of single-transmit multiple-receive signal data sets are formed, the transmitting array element spacing is 6, and each group has 9 receiving array elements, forming a total of 10×(9-1)=80 common tangent points; specifically: 1 transmit receives at 1-9 array elements, 7 transmits receives at 7-15 array elements, 13 transmits receives at 13-21 array elements, 19 transmits receives at 19-27 array elements, 25 transmits receives at 25-33 array elements, 31 transmits receives at 31-39 array elements, 37 transmits receives at 37-45 array elements, 43 transmits receives at 43-51 array elements, 49 transmits receives at 49-57 array elements, and 55 transmits receives at 55-63 array elements;

[0088] In step S2.2, in the workpiece coordinate system, the coordinates of the tool center, the coordinates of each array element, and the deflection angle θ at the three acquisition positions calculated in step S1.1 are combined and the coordinates of the 80 common tangent points of the wavefront trajectory are solved using equations (5)-(9). Finally, at the three acquisition positions, the above 80 common tangent points of the wavefront trajectory are interpolated with a spacing of 0.6 mm to obtain more common tangent points of the wavefront trajectory, thereby forming the surface contour line of the inspected workpiece 3.

[0089] S3, based on the surface contour of large and complex curved workpieces, the array element position in the tool center coordinates, and the acquired single-transmit multiple-receive mode signal to achieve double-layer medium ultrasonic imaging

[0090] In the workpiece coordinate system, the outermost horizontal coordinates of the surface contour of the inspected workpiece 3 at three locations in S2 were extracted to determine the horizontal range of the imaging area. The horizontal ranges were -22.9 mm to 15.9 mm, 45.1 mm to 84.3 mm, and 110.1 mm to 146.1 mm, respectively. The horizontal interval of the imaging area was set to 0.6 mm. Using the coordinates and deflection angle θ of each element of the linear ultrasonic phased array probe 4 calculated in S1 and the surface contour of the inspected workpiece 3 calculated in S2, the water path was calculated to be approximately 20 mm. The thickness of the inspected workpiece 3 was measured, and its maximum thickness was nearly 20 mm. Considering the thickness of the inspected workpiece 3, the water path + 1.25 times the thickness (i.e., 50 mm) is used as the detection depth. From S1, it can be seen that the vertical coordinate of the highest point of the linear ultrasonic phased array probe 4 during the scanning process is -2.97-[64-(64+1) / 2]×sin(12.48°), and the calculated value is -7.11 mm. Theoretically, the initial coordinate of the vertical range should be set to -10 mm. However, considering that the imaging time increases with the increase of the vertical range, and in the case of a 20 mm water layer, imaging with 0 mm as the initial coordinate is sufficient to reveal the surface contour lines of the inspected workpiece 3 at the three positions. Therefore, 0 mm to 50 mm is used as the common vertical range of the imaging area at the three positions, and the vertical interval of the imaging area is set to 0.1 mm. Combining the horizontal and vertical ranges of the imaging area, the number of grid points in the imaging interval at the three positions is obtained as follows: 64×500, 65×500, and 60×500, respectively.

[0091] Assume that the coordinates of any pixel point in the imaging area are P(x, 0, z), and the common tangent points of the wavefront trajectory after interpolation in S2 are all used as possible sound propagation incident points and exit points. The incident point is recorded as (x Vi ,y Vi , z Vi ), the exit point is recorded as (x Vj ,y Vj , z Vj ); the speed of sound waves in water and medium is 1480 m / s and 6300 m / s respectively; combined with any transmitting array element T i The coordinates of ( T xi , T yi , T zi ), receiving array element R j The coordinates of ( R xj , R yj , R zj) and the coordinates (x, 0, z) of any pixel point P in the imaging area, and solve the transmitting array element T according to formula (10): i The sound propagation time dataset from all common tangent points to pixel point P { t iP}.

[0092] (10)

[0093] Where c1 is 1480 m / s and c2 is 6300 m / s.

[0094] Similarly, the time it takes for the sound wave to travel from the pixel point P to the common tangent point of all wavefront trajectories and then to the receiving array element can be solved { t jP},right{ t iP}and{ t jP} take the minimum value and then sum it up to get the transmitting array element T i The acoustic propagation time from the common tangent point of the incident wavefront trajectory to the imaging area point P(x, 0, z), and then from point P(x, 0, z) to the common tangent point of the outgoing wavefront trajectory and then to the receiving array element Rj.

[0095] The delays are calculated cyclically for each of the 64 array elements and the 64×500, 65×500, and 60×500 grid points within the imaging area. The results are stored as three-dimensional matrices of 64×500×64, 65×500×64, and 60×500×64, respectively. Finally, a delay superposition operation is performed to obtain the amplitude I(x, z) of all points in the imaging area, completing ultrasonic imaging of the inspected workpiece 3.

[0096] Imaging results such as Figure 5 As shown, all images are within the dynamic display range of 0 to -30 dB. In the three SDH defect imaging images, the defect imaging amplitude is large, the focusing effect is good, and the interface position contour lines can be connected. These results demonstrate that this method can achieve ultrasonic imaging of large, complex curved surface workpieces under water immersion automated phased array inspection conditions and can clearly detect internal defects in the workpiece.

[0097] Example 2

[0098] Example 2 provided by the present invention is an embodiment of the double-layer medium ultrasonic imaging system with a common tangent point of wavefront trajectories based on the tool center coordinates provided by the present invention. The embodiment of the system includes: a position information acquisition module, a surface contour line construction module and an imaging module.

[0099] Position information acquisition module, used to obtain ultrasonic data and position information of array probe elements in the workpiece coordinate system;

[0100] A surface contour line construction module is used to obtain a multi-receiver mode signal at the position information of the array probe element, obtain the sound propagation distance corresponding to the maximum echo in the ultrasonic echo signal based on the multi-receiver mode signal, construct the corresponding wavefront trajectory tangent point, and construct the surface contour line of large and complex curved surface workpieces through the wavefront trajectory tangent point;

[0101] The imaging module is used to construct an ultrasonic image of a large and complex curved workpiece through a double-layer medium delay superposition algorithm based on the surface contour of the workpiece, the array element position under the tool center coordinates, and the acquired one-transmit-multiple-receive mode signal.

[0102] It can be understood that the double-layer medium ultrasonic imaging system with a common tangent point of the wavefront trajectories based on the tool center coordinate provided by the present invention corresponds to the double-layer medium ultrasonic imaging method with a common tangent point of the wavefront trajectories based on the tool center coordinate provided by the aforementioned embodiments. The relevant technical features of the double-layer medium ultrasonic imaging system with a common tangent point of the wavefront trajectories based on the tool center coordinate can be referred to the relevant technical features of the double-layer medium ultrasonic imaging method with a common tangent point of the wavefront trajectories based on the tool center coordinate. Specifically, the system includes the following steps:

[0103] Acquire ultrasonic data and position information of array probe elements in the workpiece coordinate system;

[0104] A one-shot-multiple-receiver mode signal is obtained at the position information of the array probe element. The sound propagation distance corresponding to the maximum echo in the ultrasonic echo signal is obtained based on the one-shot-multiple-receiver mode signal, and the corresponding wavefront trajectory tangent point is constructed. The surface contour line of the large complex curved surface workpiece is constructed through the wavefront trajectory tangent point;

[0105] According to the surface contour line of large and complex curved workpiece, the array element position under the tool center coordinates and the acquired one-transmit-multiple-receive mode signal, the ultrasonic image of the large and complex curved workpiece is constructed through the double-layer medium delay superposition algorithm.

[0106] Example 3

[0107] This embodiment provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the steps of the method for double-layer medium ultrasonic imaging based on the common tangent point of the single-transmitter and multiple-receiver wavefront trajectories of the tool center coordinate.

[0108] The method for double-layer medium ultrasonic imaging based on a common tangent point of wavefront trajectories of a single transmission and multiple reception wavefront based on the tool center coordinate comprises the following steps:

[0109] Acquire ultrasonic data and position information of array probe elements in the workpiece coordinate system;

[0110] A one-shot-multiple-receiver mode signal is obtained at the position information of the array probe element. The sound propagation distance corresponding to the maximum echo in the ultrasonic echo signal is obtained based on the one-shot-multiple-receiver mode signal, and the corresponding wavefront trajectory tangent point is constructed. The surface contour line of the large complex curved surface workpiece is constructed through the wavefront trajectory tangent point;

[0111] According to the surface contour of large and complex curved workpieces, the array element position under the tool center coordinates and the acquired one-transmit-multiple-receive mode signal, the ultrasonic image of large and complex curved workpieces is constructed through the double-layer medium delay superposition algorithm.

[0112] Example 4

[0113] This embodiment provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the steps of the double-layer medium ultrasonic imaging method based on the common tangent point of the single-transmitter and multi-receiver wavefront trajectory of the tool center coordinate.

[0114] The method for double-layer medium ultrasonic imaging based on a common tangent point of wavefront trajectories of a single transmission and multiple reception wavefront based on the tool center coordinate comprises the following steps:

[0115] Acquire ultrasonic data and position information of array probe elements in the workpiece coordinate system;

[0116] A one-shot-multiple-receiver mode signal is obtained at the position information of the array probe element. The sound propagation distance corresponding to the maximum echo in the ultrasonic echo signal is obtained based on the one-shot-multiple-receiver mode signal, and the corresponding wavefront trajectory tangent point is constructed. The surface contour line of the large complex curved surface workpiece is constructed through the wavefront trajectory tangent point;

[0117] According to the surface contour of large and complex curved workpieces, the array element position under the tool center coordinates and the acquired one-transmit-multiple-receive mode signal, the ultrasonic image of large and complex curved workpieces is constructed through the double-layer medium delay superposition algorithm.

[0118] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0119] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts 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, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0120] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0121] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0122] 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, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A double-layer medium ultrasonic imaging method with a common tangent point of wavefront trajectory based on the tool center coordinate, characterized by: include: Acquire ultrasonic data and position information of array probe elements in the workpiece coordinate system; A one-shot-multiple-receiver mode signal is obtained at the position information of the array probe element. The sound propagation distance corresponding to the maximum echo in the ultrasonic echo signal is obtained based on the one-shot-multiple-receiver mode signal, and the corresponding wavefront trajectory tangent point is constructed. The surface contour line of the large complex curved surface workpiece is constructed through the wavefront trajectory tangent point; According to the surface contour of large and complex curved workpieces, the array element position under the tool center coordinates and the acquired one-transmit-multiple-receive mode signal, the ultrasonic image of large and complex curved workpieces is constructed through the double-layer medium delay superposition algorithm.

2. The method for double-layer medium ultrasonic imaging based on a common tangent point of wavefront trajectories of a single transmission and multiple reception wavefront based on tool center coordinates according to claim 1, characterized in that: The specific steps of obtaining ultrasonic data and position information of array probe elements in the workpiece coordinate system are as follows: using the probe of the immersion ultrasonic system to scan and detect large complex curved workpieces, collecting ultrasonic data and position information of array probe elements in the workpiece coordinate system at each scanning position, and calculating the position information of the array probe elements in the workpiece coordinate system according to the center distance between two adjacent elements. d , Number of phased array probe elements N As well as the position information of the array probe elements in the workpiece coordinate system, the coordinate positions of any transmitting array element and any receiving array element are obtained.

3. The method for double-layer medium ultrasonic imaging based on a common tangent point of wavefront trajectories of a single transmission and multiple reception wavefront according to claim 2, characterized in that: The ultrasound data is full matrix data {S11, S12...S ij …S NN }, the position information is the tool center coordinates (x0, y0, z0) of the scan position and the probe-horizontal deflection angle θ; in, i and j are the transmitting element number and the receiving element number respectively, i= 1,2… N , j= 1,2… N , N is the number of probe elements.

4. The method for double-layer medium ultrasonic imaging based on a common tangent point of wavefront trajectories of a single transmission and multiple reception wavefront according to claim 3, characterized in that: The coordinate position of any transmitting array element is T i ( T xi , T yi , T zi ): The coordinate position of any receiving array element is: Where, T xi For any transmitting array element i The x-axis coordinate, T yi For any transmitting array element i The y-axis coordinate of T zi For any transmitting array element i The z-axis coordinate of R xj For any receiving array element j The x-axis coordinate, R yj For any receiving array element j The y-axis coordinate of R zj For any receiving array element j The z-axis coordinate of i For any transmitting array element, 1≤ i ≤ N , j For any receiving array element, 1≤ j ≤ N , the value range of θ is [-90°, 90°].

5. The method for double-layer medium ultrasonic imaging based on a common tangent point of wavefront trajectories of a single transmission and multiple reception wavefront based on tool center coordinates according to claim 1, characterized in that: The specific steps for constructing the surface contour of a large, complex curved workpiece using the position information of array probe elements are as follows: First, the acoustic propagation distance of the maximum echo of each transmitting and receiving element is extracted from the ultrasonic data to obtain the propagation distance of the acoustic wave from the transmitting element to the common tangent point of the wavefront trajectory and then to the receiving element; Secondly, combining the position information of the array probe elements in the workpiece coordinate system and the propagation distance of the sound wave from the transmitting element to the common tangent point of the wavefront trajectory and then to the receiving element, multiple common tangent points of the wavefront trajectory representing the surface contour of the large and complex curved workpiece are obtained; finally, the surface contour of the large and complex curved workpiece is reconstructed by interpolating the common tangent points of the wavefront trajectory.

6. The method for double-layer medium ultrasonic imaging based on a common tangent point of wavefront trajectories with a single transmission and multiple reception method based on tool center coordinates according to claim 5, characterized in that: The propagation distance of the sound wave from the transmitting array element to the common tangent point of the wavefront trajectory and then to the receiving array element is obtained by dividing the ultrasonic data into N A data set of one-transmit-multiple-receive mode signals is formed, and formulas (3) and (4) are used to calculate the N The transmitting array element number and the receiving array element number are selected from the signal data set of the one-transmit-multiple-receive mode to form k A set of one-transmit-multiple-receive signal data sets, each of which contains m Signals: （3） （4） Where, i and j are the transmitting element number and the receiving element number respectively, i =1,2… N , j =1,2… N , N is the number of probe elements; k To select the number of transmission groups, k < N ; g is the transmission interval of the array element, m for k The number of receiving array elements selected for each data set in the group data set; for k For any group of one-transmit-multiple-receive mode signals in the one-transmit-multiple-receive mode signal data set, according to the transmitting array element sequence number and the receiving array element sequence number, combined with the coordinate position of the transmitting array element and the coordinate position of the receiving array element, the sound propagation distance of the sound waves emitted by all the array elements in the group to the workpiece surface and back is calculated according to formula (5): （5） Where, T i Q For both the transmitted and received signals i The sound propagation distance when R j V + T i V The transmitting array element is i , the receiving array element is j The sound propagation distance when t ii For both transmitting and receiving signals i The sound propagation time corresponding to the maximum echo is t ij The transmitting array element is i , the receiving array element is j The sound propagation time corresponding to the maximum echo is i ≠ j , c 1 is the sound velocity of the first medium.

7. The method for double-layer medium ultrasonic imaging based on a common tangent point of wavefront trajectories of a single transmission and multiple reception wavefront based on tool center coordinates according to claim 1, characterized in that: The steps of constructing an ultrasonic image of a large complex curved surface workpiece through a double-layer medium delay superposition algorithm based on the surface contour line of the large complex curved surface workpiece, the array element position under the tool center coordinates and the acquired one-shot-multiple-receiver mode signal are as follows: using the horizontal range of the reconstructed surface contour line of the large complex curved surface workpiece to determine the horizontal range of the imaging area, and determining the vertical range of the imaging area based on the detection water path and the thickness of the surface of the large complex curved surface workpiece; combining the surface contour line of the large complex curved surface workpiece, the array element position under the tool center coordinates of the scanning position and the acquired one-shot-multiple-receiver mode signal, to construct an ultrasonic image of the large complex curved surface workpiece through a double-layer medium delay superposition algorithm.

8. A double-layer medium ultrasonic imaging system with a common tangent point of wavefront trajectory based on the tool center coordinate, characterized by: include: Position information acquisition module, used to obtain ultrasonic data and position information of array probe elements in the workpiece coordinate system; A surface contour line construction module is used to obtain a multi-receiver mode signal at the position information of the array probe element, obtain the sound propagation distance corresponding to the maximum echo in the ultrasonic echo signal based on the multi-receiver mode signal, construct the corresponding wavefront trajectory tangent point, and construct the surface contour line of large and complex curved surface workpieces through the wavefront trajectory tangent point; The imaging module is used to construct an ultrasonic image of a large and complex curved workpiece through a double-layer medium delay superposition algorithm based on the surface contour of the workpiece, the array element position under the tool center coordinates, and the acquired one-transmit-multiple-receive mode signal.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the double-layer medium ultrasonic imaging method based on the common tangent point of the wavefront trajectory of the tool center coordinates of any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the double-layer medium ultrasonic imaging method based on the common tangent point of the wavefront trajectory of the tool center coordinates of any one of claims 1 to 7 are implemented.

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