Tool center coordinate-based one-transmitting and multi-receiving wavefront trajectory common tangent point double-layer medium ultrasonic imaging method and related device

Abstract

The invention discloses a one-transmitting and multi-receiving wavefront trajectory common tangent point double-layer medium ultrasonic imaging method based on tool center coordinates and a related device, and belongs to the technical field of ultrasonic nondestructive testing. The method comprises the following steps: establishing a workpiece coordinate system by taking a certain point on a workpiece as a coordinate origin, clamping a linear phased array probe by using a multi-axis scanning system, and inverting the position and deflection angle of each array element relative to the coordinate origin on a scanning position according to a tool center coordinate returned by each scanning position; establishing a plurality of common tangent points between a wavefront track and the curved surface workpiece by utilizing multiple groups of one-transmitting and multi-receiving ultrasonic echo signals in the full-matrix data acquired at the scanning position, and further constructing a workpiece surface contour line through interpolation processing; a workpiece surface contour line measured by a wavefront trajectory common tangent point method, an array element position under a tool center coordinate and a one-transmitting-multiple-receiving mode signal are utilized, an ultrasonic image of a curved surface workpiece is constructed through a double-layer medium delay superposition algorithm, and ultrasonic imaging of the complex curved surface workpiece under a water immersion automatic phased array detection working condition is achieved.

Description

Technical Field

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

[0002] Nondestructive testing plays a vital role in industrial production. It can ensure that there are no defects in the target workpiece or equipment during the manufacturing and use process, thereby ensuring the quality and reliability of the target workpiece or equipment. At present, common nondestructive testing methods include ultrasonic testing (UT), radiographic testing (RT), magnetic particle testing (MT), penetrant testing (PT) and other methods. Among them, UT occupies an important position in nondestructive testing. The existing automated ultrasonic testing technology mainly uses water immersion ultrasonic testing method. This detection method is suitable for structures such as plates and bars with simple surface rules. For the double-layer medium imaging of simple known invariant interfaces formed by rods, plates and water, the existing algorithm can quickly process in real time.

[0003] In recent years, the demand for automated ultrasonic testing of large and complex curved workpieces has increased and become a new trend. When using water immersion ultrasonic testing methods to detect large and complex curved workpieces, large and complex curved workpieces and water will form a double-layer medium imaging of a complex unknown changing interface. The existing water immersion ultrasonic testing methods for simple structures of rods and plates cannot cope with double-layer medium imaging of complex unknown changing interfaces. In addition, most of the existing studies use single-layer medium imaging, and then extract the interface of the double-layer medium imaging in the single-layer medium imaging to convert the unknown interface imaging into known interface imaging, but this method takes a long time to extract the interface and the interface accuracy is low. Therefore, in the automated ultrasonic testing of large and complex curved workpieces, it is still a challenge to quickly extract high-precision unknown interfaces. 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 with a common tangent point of wavefront trajectories 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: The first aspect of 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 of one-shot and multiple-receiver wavefront trajectories, comprising the following steps: 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, and the sound propagation distance corresponding to the maximum echo in the ultrasonic echo signal is obtained according to the one-shot-multiple-receiver mode signal, and the corresponding wavefront trajectory common tangent point is constructed, and the surface contour line of the large complex curved surface workpiece is constructed through the wavefront trajectory common 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.

[0006] Preferably, 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 surface 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 array elements in the workpiece coordinate system, the coordinate position of any transmitting array element and any receiving array element is obtained.

[0007] 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; 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.

[0008] Further preferably, the coordinate position of any transmitting array element is T i ( T xi , T yi , T zi ):

[0009] The coordinate position of any receiving array element is:

[0010] In the formula, T xi For any transmitting array element i The x-axis coordinate of Tyi 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 of 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°].

[0011] Preferably, the specific steps of constructing the surface contour line of a large complex curved workpiece from the position information of the array probe array 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; secondly, combining the position information of the array probe array 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 wavefront trajectory common tangent points 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 wavefront trajectory common tangent points.

[0012] 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 formula (3) and formula (4) are used to calculate 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) In the formula, 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 transmitting 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) In the formula, T i Q For both the transmitted signal and the received signal 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.

[0013] Further preferably, the common tangent points of the wavefront trajectories are obtained by constructing similar triangles using the coordinate positions of the transmitting array elements, the coordinate positions of the receiving array elements, and the propagation distance of the sound waves from the transmitting array elements to the common tangent points of the wavefront trajectories and then to the receiving array elements, and calculating the coordinates of the common tangent points of the wavefront trajectories using trigonometric functions, Heron's formula, and the Pythagorean theorem, thereby obtaining all the common tangent points of the wavefront trajectories corresponding to the one-transmit-multiple-receive mode signals that represent the surface contour lines of large, complex curved workpieces.

[0014] Further preferably, after obtaining the coordinates of the common tangent point of the wavefront trajectory, loop m receiving array elements, we can obtain kThe 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 wavefront trajectory tangent point; 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.

[0015] Preferably, the steps of constructing an ultrasonic image of a large complex curved surface workpiece by using a double-layer medium delay superposition algorithm 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 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 by using a double-layer medium delay superposition algorithm.

[0016] The 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: A position information acquisition module is used to obtain ultrasonic data and position information of array probe elements in a workpiece coordinate system; A surface contour line construction module is used to obtain a one-shot-multiple-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 according to the one-shot-multiple-receiver mode signal, construct the corresponding wavefront trajectory common tangent point, and construct the surface contour line of a large complex curved surface workpiece through the wavefront trajectory common tangent point; The imaging module is used to construct an ultrasonic image of a large and complex curved surface workpiece through a double-layer medium delay superposition algorithm based on the surface contour of the large and complex curved surface workpiece, the array element position under the tool center coordinates and the acquired one-transmit-multiple-receive mode signal.

[0017] The third aspect of the present invention discloses a computer device, including 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 wavefront trajectories based on the tool center coordinates are implemented.

[0018] In a fourth aspect of the present invention, a computer-readable storage medium is disclosed, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, 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 receptions based on the tool center coordinates are implemented.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a double-layer medium ultrasonic imaging method based on the tool center coordinates of a one-shot multiple-receive wavefront trajectory common tangent point. First, the multi-axis scanning system and array probe in the water immersion ultrasonic system are used to obtain ultrasonic data and the position information of the array probe array element in the workpiece coordinate system. In this step, the acquired ultrasonic data can be used to characterize the information of the shape of the water workpiece interface, and the acquired position information can be used to reconstruct a large-scale complex interface. Secondly, a one-shot multiple-receive mode signal is acquired at the position information of the array probe array element, and the sound propagation distance corresponding to the maximum echo in the ultrasonic echo signal is acquired according to the one-shot multiple-receive mode signal, and the corresponding wavefront trajectory common tangent point is constructed, and the surface contour line of the large complex curved surface workpiece is constructed through the wavefront trajectory common tangent point; in this step, the acquired one-shot multiple-receive mode signal can be used to extract the ultrasonic echo distance corresponding to the maximum echo characterizing the water workpiece interface, and the sound propagation distance corresponding to the maximum echo in the acquired ultrasonic echo signal can be used to calculate the wavefront trajectory common tangent point, and the actual shape of the water workpiece interface can be characterized through a large number of wavefront trajectory common tangent points. Finally, according to the surface contour of the large 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 complex curved workpiece is constructed through the double-layer medium delay superposition algorithm, thereby revealing the defects in the target workpiece and quickly reconstructing the interface of the probe. In this step, the large complex curved workpiece can be ultrasonically imaged through the surface contour of the large complex curved workpiece and the acquired ultrasonic data, and the actual position of the defect under the large complex interface can be presented through the acquired array element position under the tool center coordinates and the calculated ultrasonic image of the complex curved workpiece. This method has fast running speed, high characterization accuracy, low computational complexity, wide application range, and can be combined with intelligent equipment, with good promotion and application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a flow chart of the method for ultrasonic imaging of double-layer medium with one-shot and multiple-receive wavefront trajectory common tangent point based on tool center coordinates of the present invention; Figure 2 It is a 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; Figure 3 A schematic diagram of an immersion ultrasound system used in the present invention; Figure 4 is a schematic diagram of a workpiece to be inspected according to the present invention; 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.

[0021] 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

[0022] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme 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 described embodiments 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 creative work should fall within the scope of protection of the present invention.

[0023] It should be noted that the terms "first", "second", etc. in the specification 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 sequence. It should be understood that the data used in this way can be interchanged 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" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] 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: S1, obtaining ultrasonic data and position information of array probe elements in the workpiece coordinate system; 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; S1.1, first, fix the target workpiece in the water tank of the water immersion ultrasonic system. Secondly, take a certain point of the target workpiece as the coordinate origin to establish the workpiece coordinate system xyz. Thirdly, plan the scanning path through the water immersion ultrasonic system and drive the multi-axis scanning system of the water immersion ultrasonic system to clamp the array element number. N The linear phased array probe is used to scan and inspect the target workpiece, and 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 deflection angle θ of the probe-horizontal direction, and solve the position and deflection angle θ of each array element relative to the coordinate origin at the scanning position; S1.2, 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 any receiving array element j Coordinate location R j ( R xj , R yj , R zj ); Any transmit element i The coordinates are: (1) Any receiving element j The coordinates are: (2) In the formula, T xi For any transmitting array element i The x-axis coordinate of 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 of R yj For any receiving array element j The y-axis coordinate of R zj For any receiving array elementj 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°]; S2, obtaining a one-shot-multiple-receiver mode signal at the position information of the array probe element, obtaining the sound propagation distance corresponding to the maximum echo in the ultrasonic echo signal according to the one-shot-multiple-receiver mode signal, constructing the corresponding wavefront trajectory common tangent point, and constructing the surface contour line of the large complex curved workpiece through the wavefront trajectory common tangent point; Preferably, the full matrix data {S11, S12...S ij …S NN}, construct the wavefront trajectory common tangent point for characterizing the workpiece surface contour, and then reconstruct the workpiece surface contour through the wavefront trajectory common tangent point; S2.1, in the one-transmit-multiple-receive mode, the transmitting array element and the receiving array element 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 transmitting groups, g is the transmission interval of the array element, and then N Group data set selection k A data set of signals in one-transmit-many-receive mode ( k < N ), the selected transmitting array element number refers to formula (3): (3) Assumptions kThe 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): (4) After selecting the transmit and receive 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.

[0025] 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 the 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: (5) In the formula, T i Q For both the transmitted signal and the received signal 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 the maximum echo, c 1 is the sound velocity of the first medium.

[0026] S2.3, such as Figure 2 As shown, assuming that the interface normal is Q and V 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 Wlq congruent; line segment 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 line 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: (6) 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 T i VR j In the line segment T i V , R j V , D ijThe 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 segment T i F The specific calculation formula is: (7) In the formula, l For triangle T i VR j half of the circumference; S2.5, over V Point to Point T i Draw a perpendicular line from 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 angle θ and trigonometric function to solve line segment 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: (8) 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 , zV ); the specific solution process is: (9) 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, 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 wavefront trajectory tangent point; S2.7, using formulas (3)-(9), calculate k The common tangent points of all wavefront trajectories corresponding to the signal in the one-transmit-multiple-receive mode 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 surface contour of the target workpiece.

[0027] S3, based on the surface contour of the large complex curved surface workpiece, the array element position under the tool center coordinates and the acquired one-transmit-multiple-receive mode signal, an ultrasonic image of the large complex curved surface workpiece is constructed through a double-layer medium delay superposition algorithm.

[0028] Preferably, the horizontal range of the target workpiece surface contour 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 distance and the thickness of the target workpiece; the workpiece surface contour 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.

[0029] 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 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.

[0030] In the following examples, the water immersion ultrasonic system used is as follows Figure 3As shown, it includes 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 6 and a display 7; the multi-axis scanning system 1 can clamp the linear ultrasonic phased array probe 4 and immerse it in the water tank 2. The ultrasonic phased array probe 4 adopts an ultrasonic phased array probe of model 5L64-0.6×10, with a center frequency fs=5 MHz, 64 array elements, 0.6 mm array element center spacing, 10 mm array element length, and 0.55 mm array element width. Two ultrasonic transmission / reception 32-channel interfaces are provided on the panel of the ultrasonic signal acquisition system 5. One end of the ultrasonic signal acquisition system 5 is connected to the linear ultrasonic phased array probe 4 through an adapter and two ultrasonic transmission / reception 32-channel interfaces, and the other end is connected to the host 6 and the display 7 in sequence.

[0031] In the following embodiments, an aluminum concave workpiece with three side drilling defects is used as the inspected workpiece 3. Figure 4 As shown, the aluminum concave workpiece with three edge drilling defects has a total of three edge drilling defects. The leftmost edge drilling hole has a diameter of 2 mm and is 4 mm away from the concave surface, the middle edge drilling hole has a diameter of 2 mm and is 6 mm away from the concave surface, and the rightmost edge drilling hole has a diameter of 2 mm and is 8 mm away from the concave surface.

[0032] Example 1 The ultrasonic imaging of the inspected workpiece 3 is performed using a double-layer medium ultrasonic imaging method with a common tangent point of wavefront trajectories based on the tool center coordinates. The specific steps are as follows: 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 4 S1.1, first, in Figure 3 The water tank 2 of the water immersion ultrasonic system shown in the figure is filled with water, and then the workpiece 3 to be inspected is immersed in the water tank 2 and fixed by a clamping device. Figure 3 The experimental water immersion ultrasonic system is installed in the manner shown, and 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 to be inspected, and the center of the leftmost linear ultrasonic phased array probe 4 is used as the coordinate origin, and the horizontal direction is the x-axis and the vertical direction is the z-axis to establish the workpiece coordinate system xyz. Again, the water immersion ultrasonic system is used to plan the scanning path, and 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 and inspect the workpiece 3 to collect 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 deflection angle θ of the probe-horizontal direction, 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; S1.2, set 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 ( R xj ，R yj , R zj ), full matrix data collection is performed at three positions above the defect of the inspected workpiece 3.

[0033] 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 S2.1, the full matrix data {S11, S12…S ij …S NN}Divided into N A signal data set of one-transmit-many-receive mode is formed, and then N Group data set selection k A data set of signals in 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 one-transmit-multiple-receive mode 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 1-9 array elements receive, 7 transmit 7-15 array elements receive, 13 transmit 13-21 array elements receive, 19 transmit 19-27 array elements receive, 25 transmit 25-33 array elements receive, 31 transmit 31-39 array elements receive, 37 transmit 37-45 array elements receive, 43 transmit 43-51 array elements receive, 49 transmit 49-57 array elements receive, 55 transmit 55-63 array elements receive; 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 S1.1 are combined and the coordinates of 80 wavefront trajectory tangent points are solved by equations (5)-(9). Finally, at the three acquisition positions, the above 80 wavefront trajectory tangent points are interpolated with a spacing of 0.6 mm to obtain more wavefront trajectory tangent points, thereby forming the surface contour line of the inspected workpiece 3.

[0034] S3, based on 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, realizes double-layer medium ultrasonic imaging In the workpiece coordinate system, the outermost horizontal coordinates of the horizontal position of the surface contour line of the inspected workpiece 3 at three positions in S2 are extracted to determine the horizontal range of the imaging area, which are -22.9 mm~15.9 mm, 45.1 mm~84.3 mm, and 110.1 mm~146.1 mm, respectively, and the horizontal interval of the imaging area is set to 0.6 mm; using the coordinates of each element of the linear ultrasonic phased array probe 4 calculated in S1, the deflection angle θ and the surface contour line of the inspected workpiece 3 calculated in S2, the water path is calculated to be approximately 20 mm. The thickness of the inspected workpiece 3 is measured, and the thickest is nearly 20 mm. Combined with the thickness of the inspected workpiece 3, the water path + 1.25 times the thickness (i.e., 50 mm) is taken 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. In theory, the initial coordinate of the vertical range should be set to -10 mm, but considering that the imaging time will increase with the increase of the vertical range, and in the case of a water layer of 20 mm, the imaging with 0 mm as the initial coordinate is sufficient to show the surface contour lines of the inspected workpiece 3 at the three positions. Therefore, 0 mm~50 mm is taken 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; combined with the horizontal range and vertical range of the imaging area, it can be obtained that the number of grid points in the imaging interval at the three positions are: 64×500, 65×500, and 60×500, respectively.

[0035] 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}.

[0036] (10) Where c1 is 1480 m / s; c2 is 6300 m / s.

[0037] 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 them up to get the transmitting array element T i The acoustic propagation time from point P(x, 0, z) to 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.

[0038] The delay is calculated for the 64 array elements and the 64×500, 65×500, and 60×500 grid points in the imaging area. The results are saved in the form of three-dimensional matrices of 64×500×64, 65×500×64, and 60×500×64, respectively. Finally, the delay superposition operation is performed to obtain the amplitude I(x, z) of all points in the imaging area, and the ultrasonic imaging of the inspected workpiece 3 is completed.

[0039] The imaging results are as follows Figure 5 As shown in the figure, all images are within the dynamic display range of 0~-30 dB. In the three transverse through hole defect imaging images, the defect imaging amplitude is large, the focusing effect is good, and the interface position contour line can be connected. This result shows that this method can realize ultrasonic imaging of large and complex curved surface workpieces under water immersion automated phased array inspection conditions, and can significantly detect internal defects of the workpiece.

[0040] Example 2 Embodiment 2 provided by the present invention is an embodiment of a 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.

[0041] A position information acquisition module is used to obtain ultrasonic data and position information of array probe elements in a workpiece coordinate system; A surface contour line construction module is used to obtain a one-shot-multiple-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 according to the one-shot-multiple-receiver mode signal, construct the corresponding wavefront trajectory common tangent point, and construct the surface contour line of a large complex curved surface workpiece through the wavefront trajectory common tangent point; The imaging module is used to construct an ultrasonic image of a large and complex curved surface workpiece through a double-layer medium delay superposition algorithm based on the surface contour of the large and complex curved surface workpiece, the array element position under the tool center coordinates and the acquired one-transmit-multiple-receive mode signal.

[0042] It can be understood that the double-layer medium ultrasonic imaging system with a common tangent point of wavefront trajectories based on tool center coordinates provided by the present invention corresponds to the double-layer medium ultrasonic imaging method with a common tangent point of wavefront trajectories based on tool center coordinates provided by the aforementioned embodiments. The relevant technical features of the double-layer medium ultrasonic imaging system with a common tangent point of wavefront trajectories based on tool center coordinates can refer to the relevant technical features of the double-layer medium ultrasonic imaging method with a common tangent point of wavefront trajectories based on tool center coordinates, which specifically includes the following steps: 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, and the sound propagation distance corresponding to the maximum echo in the ultrasonic echo signal is obtained according to the one-shot-multiple-receiver mode signal, and the corresponding wavefront trajectory common tangent point is constructed, and the surface contour line of the large complex curved surface workpiece is constructed through the wavefront trajectory common tangent point; According to the surface contour of the 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.

[0043] Example 3 This embodiment provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the steps of the method for double-layer medium ultrasonic imaging with a common tangent point of wavefront trajectories based on the coordinates of the tool center.

[0044] The one-shot-multiple-receiver wavefront trajectory common tangent point double-layer medium ultrasonic imaging method based on tool center coordinates comprises the following steps: 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, and the sound propagation distance corresponding to the maximum echo in the ultrasonic echo signal is obtained according to the one-shot-multiple-receiver mode signal, and the corresponding wavefront trajectory common tangent point is constructed, and the surface contour line of the large complex curved surface workpiece is constructed through the wavefront trajectory common 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.

[0045] Example 4 This embodiment provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps of the double-layer medium ultrasonic imaging method with a common tangent point of the wavefront trajectory of one-shot and multiple-receiver based on the tool center coordinates are implemented.

[0046] The one-shot-multiple-receiver wavefront trajectory common tangent point double-layer medium ultrasonic imaging method based on tool center coordinates comprises the following steps: 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, and the sound propagation distance corresponding to the maximum echo in the ultrasonic echo signal is obtained according to the one-shot-multiple-receiver mode signal, and the corresponding wavefront trajectory common tangent point is constructed, and the surface contour line of the large complex curved surface workpiece is constructed through the wavefront trajectory common 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.

[0047] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. 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 disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0048] 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 flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, 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 flowchart and / or block diagram. 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.

[0049] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate 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 A function specified in one or more boxes.

[0050] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant 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 within the scope of protection of the claims of the present invention.

Claims

1. A double-layer medium ultrasonic imaging method based on a common tangent point of wavefront trajectory with one shot and multiple receptions based on the tool center coordinate, characterized in that: 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, and the sound propagation distance corresponding to the maximum echo in the ultrasonic echo signal is obtained according to the one-shot-multiple-receiver mode signal, and the corresponding wavefront trajectory common tangent point is constructed, and the surface contour line of the large complex curved surface workpiece is constructed through the wavefront trajectory common 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 the tool center coordinates of one-shot-multiple-receiver wavefront trajectory common tangent point according to claim 1, characterized in that: The specific steps of obtaining ultrasonic data and the position information of array probe elements in the workpiece coordinate system are as follows: the large complex curved workpiece is detected by scanning with the probe of the water immersion ultrasonic system, and ultrasonic data and the position information of array probe elements in the workpiece coordinate system are collected at each scanning position. d , Number of phased array probe elements N As well as the position information of the array probe array elements in the workpiece coordinate system, the coordinate position of any transmitting array element and any receiving array element is obtained.

3. The method for double-layer medium ultrasonic imaging based on the tool center coordinates of one-shot-multiple-receiver wavefront trajectory common tangent point according to claim 2, characterized in that: The ultrasound data is a 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 array element number and the receiving array 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 the tool center coordinates of one-shot-multiple-receiver wavefront trajectory common tangent point 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: In the formula, T xi For any transmitting array element i The x-axis coordinate of T yi For any transmitting array element i The y-axis coordinate of T zi For any transmitting element i The z-axis coordinate of R xj For any receiving array element j The x-axis coordinate of 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 the tool center coordinates of one-shot-multiple-receiver wavefront trajectory common tangent point according to claim 1, characterized in that: The specific steps of constructing the surface contour of a large complex curved workpiece from the position information of the array probe array elements are as follows: first, the acoustic propagation distance of the maximum echo of each transmitting-receiving array element is extracted from the ultrasonic data to obtain the propagation distance of the acoustic wave from the transmitting array element to the common tangent point of the wavefront trajectory and then to the receiving array 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 the common tangent point of wavefront trajectory of one-shot multiple-receiver 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 formula (3) and formula (4) are used to calculate 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） In the formula, 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 transmitting 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） In the formula, T i Q For both the transmitted signal and the received signal 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 the tool center coordinates of one-shot-multiple-receiver wavefront trajectory common tangent point according to claim 1, characterized in that: According to 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, the steps of constructing the ultrasonic image of the large complex curved surface workpiece through the double-layer medium delay superposition algorithm are specifically 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 according to the detection water path and the thickness of the surface of the large complex curved surface workpiece, determine the vertical range of the imaging area; 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, construct the ultrasonic image of the large complex curved surface workpiece through the 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 in that: include: A position information acquisition module is used to obtain ultrasonic data and position information of array probe elements in a workpiece coordinate system; A surface contour line construction module is used to obtain a one-shot-multiple-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 according to the one-shot-multiple-receiver mode signal, construct the corresponding wavefront trajectory common tangent point, and construct the surface contour line of a large complex curved surface workpiece through the wavefront trajectory common tangent point; The imaging module is used to construct an ultrasonic image of a large and complex curved surface workpiece through a double-layer medium delay superposition algorithm based on the surface contour of the large and complex curved surface 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, characterized in that: 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 one-shot and multiple-receiver wavefront trajectory based on the tool center coordinates as described in 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 of one-shot-multiple-receiver wavefront trajectory common tangent point based on tool center coordinates as described in any one of claims 1 to 7 are implemented.

Images