A spatial coordinate calibration type phased array ultrasonic defect three-dimensional imaging method

Abstract

This invention provides a spatial coordinate calibration-based phased array ultrasonic defect three-dimensional imaging method, belonging to the field of ultrasonic nondestructive testing technology. It can significantly alleviate or solve the problems of existing phased array ultrasonic testing methods, such as the lack of a unified spatial coordinate reference, the difficulty in characterizing the three-dimensional morphology of defects using two-dimensional imaging, and insufficient quantification capabilities. This invention acquires detection parameters of the workpiece spatial reference, probe calibration state, scanning state, and ultrasonic echo state; establishes a global three-dimensional coordinate system for the workpiece and its coordinate transformation relationship with the local coordinate system of the phased array probe; updates the coordinate transformation relationship during scanning; acquires ultrasonic echo signals and binds ultrasonic features to the global three-dimensional coordinate system of the workpiece; and forms a three-dimensional ultrasonic mesh data model, identifies the defect mesh, reconstructs the three-dimensional defect model, and outputs the spatial location, size parameters, offset, and three-dimensional imaging results of the defect. This method improves the three-dimensional localization, morphology reconstruction, and quantitative detection capabilities of defects in complex workpieces.

Description

Technical Field

[0001] This invention belongs to the field of ultrasonic nondestructive testing technology, specifically relating to a spatial coordinate calibration phased array ultrasonic defect three-dimensional imaging method. Background Technology

[0002] Phased array ultrasonic testing technology is one of the most widely used testing technologies in the field of industrial non-destructive testing. By controlling the excitation and reception delays of multiple array elements, it achieves the deflection, focusing, and electronic scanning of the ultrasonic beam, enabling the detection of defects such as internal cracks, porosity, inclusions, lack of fusion, incomplete penetration, and hole wall defects in workpieces. As industrial equipment such as pressure vessels, pressure pipelines, aerospace components, gas turbine parts, rail transit components, wind power composite material components, and large castings and forgings develop towards higher parameters, higher reliability, and more complex structures, the traditional two-dimensional ultrasonic testing results, which rely on human experience, are no longer sufficient to meet the requirements for accurate location, morphological evaluation, and quantitative determination of internal defects in complex components. Therefore, how to obtain three-dimensional testing results corresponding to the actual spatial position of the workpiece during phased array ultrasonic testing has become a crucial problem that urgently needs to be solved in the field of industrial non-destructive testing.

[0003] Current phased array ultrasonic testing typically uses A-scan, B-scan, C-scan, or sector scan images as the primary imaging results, determining the approximate location and size of defects based on echo amplitude, propagation time, and scanning angle. While some testing methods can generate 3D display results through multiple scans or post-processing, their data foundation largely originates from 2D cross-sectional images or local scan coordinates, lacking a unified global 3D coordinate system consistent with workpiece geometric datum, design model, or 3D scanning model. In actual testing, changes in the phased array probe's position, attitude deflection, wedge incident angle, workpiece curvature, thickness variations, and material sound velocity deviations all affect the ultrasonic wave propagation path, causing a shift between the spatial location corresponding to the echo signal and the actual physical location of the workpiece. Relying solely on 2D image overlay or relative scan positions for 3D reconstruction easily leads to inaccurate defect spatial positioning, boundary distortion, and dimensional quantization errors.

[0004] Furthermore, for complex inspection objects such as curved surfaces, irregularly shaped components, components with varying thicknesses, weld areas, and screw holes, existing methods often struggle to simultaneously consider the correspondence between the probe's local coordinates, the workpiece's global coordinates, the beam propagation direction, and echo characteristics. After acquisition, ultrasonic echo data is often processed only as image grayscale or amplitude data, failing to bind each set of echo characteristics to the corresponding three-dimensional spatial coordinates of the workpiece, and failing to correct the spatial coordinates based on sound velocity deviation, beam refraction, surface normal, and thickness variations. Therefore, existing technologies struggle to form a complete technical closed loop from coordinate calibration, probe dynamic positioning, coordinate-based ultrasonic data acquisition, spatial coordinate correction, three-dimensional mesh mapping to defect three-dimensional reconstruction and parameter quantization output.

[0005] In summary, existing phased array ultrasonic testing methods have at least the following shortcomings: First, they lack a global three-dimensional coordinate system for the workpiece based on its geometric datum, design model, or three-dimensional scanning model, making it difficult for defect detection results to correspond to the actual spatial position and design coordinates of the workpiece. Second, the transformation relationship between the probe's local coordinate system and the workpiece's global three-dimensional coordinate system is unclear, making it difficult to compensate for changes in probe position and orientation during scanning in real time. Third, there is a lack of binding relationship between ultrasonic echo characteristics and probe pose, beam direction, and workpiece spatial coordinates, making it difficult to support subsequent three-dimensional quantitative analysis. Fourth, spatial coordinate errors caused by sound velocity deviation, beam refraction, and changes in workpiece curvature and thickness are not effectively corrected, resulting in insufficient imaging accuracy for complex workpiece defects. Fifth, existing three-dimensional display or reconstruction results are mostly biased towards image visualization, lacking a quantitative basis for parameters such as defect volume, cross-sectional area, equivalent diameter, maximum extension length, and offset based on three-dimensional mesh units and the workpiece's global coordinates.

[0006] Therefore, it is necessary to propose a spatial coordinate calibration phased array ultrasonic three-dimensional imaging method for defects to improve the three-dimensional positioning accuracy, morphological reconstruction integrity, and quantitative detection reliability of internal defects in complex industrial components. Summary of the Invention

[0007] The present invention aims to solve at least one of the technical problems existing in the prior art, and provides a spatial coordinate calibration phased array ultrasonic defect three-dimensional imaging method.

[0008] This invention provides a spatial coordinate calibration-based three-dimensional imaging method for phased array ultrasonic defects, comprising the following steps: S1: Acquire detection parameters used to characterize the workpiece spatial reference, phased array probe calibration status, scanning status, and ultrasonic echo status; S2: Establish a global three-dimensional coordinate system for the workpiece based on the detection parameters, determine the coordinate boundaries of the area to be detected, and determine the coordinate transformation relationship between the local coordinate system of the phased array probe and the global three-dimensional coordinate system of the workpiece; S3: Based on the coordinate boundary and the coordinate transformation relationship, determine the scanning pose of each scanning point and the corresponding phased array probe. During phased array ultrasonic scanning, update the coordinate transformation relationship according to the real-time spatial position and attitude angle of the phased array probe, collect the ultrasonic echo signal corresponding to each scanning point, and bind the ultrasonic features extracted from the ultrasonic echo signal to the corresponding global three-dimensional coordinates of the workpiece according to the updated coordinate transformation relationship to form an ultrasonic dataset with spatial coordinate labels. S4: Perform signal preprocessing and spatial coordinate correction on the ultrasound dataset to obtain a coordinate-corrected ultrasound dataset. Then, perform three-dimensional spatial meshing on the area to be detected according to the coordinate boundaries to form multiple three-dimensional mesh units. Map the coordinate-corrected ultrasound dataset to the corresponding three-dimensional mesh units to form a three-dimensional ultrasound mesh data model. S5: Identify the defect mesh based on the three-dimensional ultrasonic mesh data model, and reconstruct the three-dimensional morphology of the defect mesh to obtain a three-dimensional reconstruction model of the defect. S6: Based on the defect 3D reconstruction model and the workpiece global 3D coordinate system, output the defect spatial location, size parameters, offset, and 3D imaging results.

[0009] Furthermore, the detection parameters include workpiece spatial reference parameters, probe calibration parameters, scanning status parameters, and ultrasonic echo status parameters, wherein the workpiece spatial reference parameters include boundary parameters of the area to be detected.

[0010] Specifically, establishing the global three-dimensional coordinate system of the workpiece includes: The coordinate datum is determined based on the geometric datum, assembly datum, design model, or 3D scanning model of the workpiece; and The coordinate boundary is determined based on the coordinate reference and the spatial range of the area to be detected.

[0011] Specifically, determining the coordinate transformation relationship includes: Establish the local coordinate system of the phased array probe; and determine the coordinate transformation relationship composed of rotation and translation relationships based on the probe's initial spatial position, initial probe attitude, probe array element parameters, beam parameters, and wedge parameters.

[0012] Furthermore, the ultrasound dataset with spatial coordinate labels includes: Extract ultrasonic features from the ultrasonic echo signal, including at least the propagation time, wherein the ultrasonic features also include at least one of echo amplitude, phase shift, signal attenuation coefficient and reflection boundary features; The coordinates of the echo reflection point are determined based on the propagation duration, the sound velocity of the workpiece material, and the sound beam propagation path; and The coordinates of the echo reflection point are converted into the global three-dimensional coordinates of the workpiece based on the updated coordinate transformation relationship.

[0013] Specifically, the signal preprocessing includes at least one of noise filtering, clutter suppression, and gain compensation; the spatial coordinate correction includes determining the coordinate correction amount based on the sound velocity of the workpiece material, the sound wave propagation path, the probe incident angle, the workpiece curvature, or the thickness variation, and using the coordinate correction amount to correct the spatial coordinates in the ultrasonic dataset after the signal preprocessing.

[0014] Furthermore, forming the three-dimensional ultrasound mesh data model includes: The mesh division granularity is determined based on the detection resolution and target positioning accuracy. The coordinate-corrected ultrasound dataset is assigned to corresponding three-dimensional mesh cells according to the spatial coordinate matching relationship; and Attribute fusion is performed on ultrasonic features within the same three-dimensional mesh cell.

[0015] Furthermore, the obtained three-dimensional reconstruction model of the defect includes: Candidate defect meshes are determined based on the ultrasonic characteristics of the workpiece substrate and the defect identification threshold. The candidate defect mesh is divided into three-dimensional connected components to obtain the defect mesh region; and The defective mesh region is subjected to boundary fitting, edge refinement, and hole filling.

[0016] Furthermore, the dimensional parameters include at least one of the maximum extension length, equivalent diameter, cross-sectional area, and volume; the offset is determined based on the spatial distance of the defect spatial location relative to the workpiece reference, design model reference, weld centerline, or hole axis.

[0017] Specifically, the three-dimensional imaging results include the three-dimensional reconstruction model of the defect, the spatial coordinate labels of the defect, and the quantization parameters of the defect.

[0018] The beneficial effects of this invention are as follows: This invention establishes a coordinate transformation relationship between the workpiece's global three-dimensional coordinate system and the phased array probe's local coordinate system, thereby mapping the ultrasonic echo signal to the workpiece's actual spatial position and improving the accuracy of defect spatial localization. During the scanning process, the coordinate transformation relationship is updated based on the phased array probe's real-time spatial position and attitude angle, and ultrasonic features are bound to the corresponding workpiece's global three-dimensional coordinates, forming an ultrasonic dataset with spatial coordinate labels, providing a spatial data foundation for three-dimensional imaging and defect quantification. Through signal preprocessing and spatial coordinate correction, the impact of noise, clutter, sound velocity deviation, beam refraction, and workpiece curvature and thickness variations on the detection results is reduced, improving the stability of complex workpiece defect imaging. Through three-dimensional spatial mesh partitioning, ultrasonic data mapping, defect mesh recognition, and three-dimensional morphology reconstruction, a three-dimensional reconstruction model of the defect can be obtained, and the defect's spatial position, size parameters, offset, and three-dimensional imaging results can be output, achieving three-dimensional quantitative detection of defects. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the steps of a spatial coordinate calibration phased array ultrasonic defect three-dimensional imaging method according to a specific embodiment of the present invention. Figure 2 This is a schematic diagram illustrating the calibration of the workpiece's global coordinate system and the probe's local coordinate system in a spatial coordinate calibration phased array ultrasonic defect three-dimensional imaging method according to a specific embodiment of the present invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] like Figure 1 As shown in the figure, a spatial coordinate calibration phased array ultrasonic defect three-dimensional imaging method provided by a specific embodiment of the present invention includes the following steps: S1: Acquire detection parameters used to characterize the workpiece spatial reference, phased array probe calibration status, scanning status, and ultrasonic echo status; S2: Establish a global three-dimensional coordinate system for the workpiece based on the detection parameters, determine the coordinate boundaries of the area to be detected, and determine the coordinate transformation relationship between the local coordinate system of the phased array probe and the global three-dimensional coordinate system of the workpiece; S3: Based on the coordinate boundary and the coordinate transformation relationship, determine the scanning pose of each scanning point and the corresponding phased array probe. During phased array ultrasonic scanning, update the coordinate transformation relationship according to the real-time spatial position and attitude angle of the phased array probe, collect the ultrasonic echo signal corresponding to each scanning point, and bind the ultrasonic features extracted from the ultrasonic echo signal to the corresponding global three-dimensional coordinates of the workpiece according to the updated coordinate transformation relationship to form an ultrasonic dataset with spatial coordinate labels. S4: Perform signal preprocessing and spatial coordinate correction on the ultrasound dataset to obtain a coordinate-corrected ultrasound dataset. Then, perform three-dimensional spatial meshing on the area to be detected according to the coordinate boundaries to form multiple three-dimensional mesh units. Map the coordinate-corrected ultrasound dataset to the corresponding three-dimensional mesh units to form a three-dimensional ultrasound mesh data model. S5: Identify the defect mesh based on the three-dimensional ultrasonic mesh data model, and reconstruct the three-dimensional morphology of the defect mesh to obtain a three-dimensional reconstruction model of the defect. S6: Based on the defect 3D reconstruction model and the workpiece global 3D coordinate system, output the defect spatial location, size parameters, offset, and 3D imaging results.

[0022] In one embodiment, the workpiece global three-dimensional coordinate system is used to uniformly describe the spatial positions of the area to be inspected, scanning points, probe scanning pose, echo reflection points, three-dimensional mesh cells, and the three-dimensional reconstruction model of defects within the workpiece. By establishing a correspondence between the phased array probe's local coordinate system and the workpiece global three-dimensional coordinate system, the phased array ultrasonic echo signal no longer corresponds only to the relative sound path or two-dimensional scanning section, but rather to the spatial position under the workpiece's global three-dimensional coordinate system.

[0023] Preferably, the detection parameters are divided into workpiece-side parameters, probe-side parameters, scanning-side parameters, and echo-side parameters according to the acquisition object; wherein, the workpiece-side parameters are used to establish the global three-dimensional coordinate system of the workpiece and the coordinate boundary, the probe-side parameters are used to establish the local coordinate system of the phased array probe and the coordinate transformation relationship, the scanning-side parameters are used to determine the scanning point and the scanning pose of the probe, and the echo-side parameters are used to generate the ultrasonic dataset with spatial coordinate labels.

[0024] Furthermore, the coordinate transformation relationship is integrated throughout the scanning pose determination, ultrasonic feature coordinate binding, and spatial coordinate correction processes. In other words, the coordinate transformation relationship obtained in S2 serves as the basis for determining the probe scanning pose and updating the real-time coordinate transformation relationship in S3; the updated coordinate transformation relationship in S3 serves as the basis for binding ultrasonic features to the workpiece's global three-dimensional coordinates; and the spatial coordinates corrected in S4 serve as the basis for three-dimensional mesh mapping and subsequent defect quantization.

[0025] Based on the above basic implementation method, the detection parameters include workpiece spatial reference parameters, probe calibration parameters, scanning state parameters and ultrasonic echo state parameters, and the workpiece spatial reference parameters include the boundary parameters of the area to be detected.

[0026] Furthermore, the workpiece spatial reference parameters include at least one of the following: workpiece geometric reference surface, assembly reference, design model coordinates, three-dimensional scanning model coordinates, spatial range of the area to be inspected, and workpiece surface morphology parameters. The probe calibration parameters include at least one of the following: phased array probe element arrangement parameters, element spacing, element inherent delay, wedge angle, wedge sound velocity, beam angle range, and focusing parameters. The scanning state parameters include at least one of the following: scanning point number, scanning trajectory, probe spatial position, probe attitude angle, scanning step size, and scanning direction. The ultrasonic echo state parameters include at least one of the following: echo amplitude, propagation duration, phase shift, signal attenuation coefficient, echo envelope peak value, and reflection boundary characteristics.

[0027] Specifically, the probe attitude angle includes at least one of pitch angle, yaw angle, and roll angle. The probe spatial position and the probe attitude angle are obtained through laser positioning, structured light positioning, encoder, robotic arm end effector pose, inertial measurement unit, or a combination of the above methods, and are synchronized with the ultrasonic echo signal of the corresponding scanning point.

[0028] In one specific implementation, establishing the global three-dimensional coordinate system of the workpiece includes: The coordinate datum is determined based on the geometric datum, assembly datum, design model, or 3D scanning model of the workpiece; and The coordinate boundary is determined based on the coordinate reference and the spatial range of the area to be detected.

[0029] In this embodiment, the coordinate reference includes the coordinate origin, coordinate axis directions, and spatial scale reference. For workpieces with regular geometric structures, the reference plane, central axis, assembly hole axis, weld centerline, or end face of the workpiece are used as the coordinate reference; for curved workpieces, irregularly shaped components, or components with varying thickness, reference points, reference lines, or reference surfaces in the workpiece design model or 3D scanning model are used as the coordinate reference. The coordinate boundary includes the spatial range of the area to be detected in the X-axis, Y-axis, and Z-axis directions.

[0030] Furthermore, when the area to be inspected is a weld area, the coordinate boundary is determined based on the weld centerline, weld width, weld thickness direction, and weld extension direction; when the area to be inspected is a hole structure, the coordinate boundary is determined based on the hole axis, hole end face, hole diameter range, and hole depth range; when the area to be inspected is a curved surface component, the coordinate boundary is determined based on the surface normal of the curved surface model, curvature variation range, and thickness direction.

[0031] In another specific embodiment, determining the coordinate transformation relationship includes: Establish the local coordinate system of the phased array probe; and determine the coordinate transformation relationship composed of rotation and translation relationships based on the probe's initial spatial position, initial probe attitude, probe array element parameters, beam parameters, and wedge parameters.

[0032] In this embodiment, the local coordinate system of the phased array probe uses the array center of the phased array probe, the wedge incident reference point, or the probe installation reference point as the local coordinate origin, and establishes local coordinate axes with the array element arrangement direction, the sound beam incident reference direction, and the probe height direction. The coordinate transformation relationship is used to convert the echo reflection point coordinates in the local coordinate system of the phased array probe into the global three-dimensional coordinates of the workpiece in the global three-dimensional coordinate system of the workpiece.

[0033] Specifically, the rotation relationship is determined by the probe's initial posture and the real-time posture angle during the scanning process, and the translation relationship is determined by the probe's initial spatial position and the real-time spatial position during the scanning process. For the first... For each scan point, the coordinate transformation relationship is expressed as a homogeneous coordinate transformation relationship consisting of a rotation matrix and a translation vector:

[0034] in, Indicates the first The coordinate transformation relationship corresponding to each scan point This represents the rotation matrix determined by the probe's attitude angle. This represents the position vector of the phased array probe reference point in the global three-dimensional coordinate system of the workpiece.

[0035] Furthermore, when the coordinates of the echo reflection point in the local coordinate system of the phased array probe are... At that time, the coordinates of the echo reflection point in the global three-dimensional coordinate system of the workpiece are obtained through the coordinate transformation relationship. The transformation relationship is expressed as follows:

[0036] Right now:

[0037] in, Indicates the first The coordinates of each echo reflection point in the local coordinate system of the phased array probe. Indicates the first The coordinates of each echo reflection point in the global three-dimensional coordinate system of the workpiece. As spatial coordinate labels corresponding to ultrasonic features, they are used for subsequent spatial coordinate correction, three-dimensional mesh mapping, and defect parameter quantization.

[0038] In another specific embodiment, forming the ultrasound dataset with spatial coordinate labels includes: Extract ultrasonic features from the ultrasonic echo signal, including at least the propagation time, wherein the ultrasonic features also include at least one of echo amplitude, phase shift, signal attenuation coefficient and reflection boundary features; The coordinates of the echo reflection point are determined based on the propagation duration, the sound velocity of the workpiece material, and the sound beam propagation path; and The coordinates of the echo reflection point are converted into the global three-dimensional coordinates of the workpiece based on the updated coordinate transformation relationship.

[0039] Furthermore, the propagation duration is used to determine the acoustic path position of the echo reflection point along the propagation direction of the sound beam, the echo amplitude is used to characterize the reflection interface strength or defect reflection intensity, the phase shift is used to characterize material discontinuity regions or interface abrupt changes, the signal attenuation coefficient is used to characterize abnormal loss during sound energy propagation, and the reflection boundary feature is used to characterize defect boundaries or workpiece structural boundaries.

[0040] Specifically, each ultrasonic data record with spatial coordinate labels includes the scan point number, sampling time, probe spatial position, probe attitude angle, beam parameters, ultrasonic characteristics, and global three-dimensional coordinates of the workpiece. The ultrasonic data record is represented as follows:

[0041] in, Indicates the first The first scan point Ultrasonic data records corresponding to each echo reflection point; Indicates the scan point number; Indicates the sampling time; Indicates the spatial position of the probe; Indicates the probe's attitude angle; Indicates beam parameters; Indicates the echo amplitude; Indicates the duration of transmission; Indicates phase shift; Indicates the signal attenuation coefficient; This represents the global three-dimensional coordinates of the corresponding workpiece.

[0042] In another specific embodiment, the signal preprocessing includes at least one of noise filtering, clutter suppression, and gain compensation; the spatial coordinate correction includes determining a coordinate correction amount based on the sound velocity of the workpiece material, the sound wave propagation path, the probe incident angle, the curvature or thickness change of the workpiece, and using the coordinate correction amount to correct the spatial coordinates in the ultrasonic dataset after the signal preprocessing.

[0043] Furthermore, the noise filtering is used to reduce the impact of environmental noise and equipment noise on the echo amplitude, propagation time, and phase shift extraction; the clutter suppression is used to eliminate invalid echoes formed by workpiece surface scattering, structural boundary reflection, coupling state changes, and material structure noise; and the gain compensation is used to compensate for the reduction in echo amplitude caused by increased sound path, surface scattering, or material attenuation.

[0044] Specifically, the spatial coordinate correction includes at least one of sound velocity correction, refraction correction, surface normal correction, and thickness compensation. The sound velocity correction determines the deviation between the actual sound velocity and the set sound velocity based on a reference reflector, a known thickness region, or a reference echo, and corrects the echo propagation depth. The refraction correction corrects the sound beam propagation direction based on the probe incident angle, wedge parameters, workpiece surface normal, and workpiece material sound velocity. The surface normal correction obtains the local surface normal based on the workpiece design model or three-dimensional scanning model, correcting the coordinate offset of the curved surface region. The thickness compensation corrects the position of the echo reflection point in the thickness direction based on local thickness changes in the workpiece.

[0045] In another specific embodiment, forming the three-dimensional ultrasound mesh data model includes: The mesh division granularity is determined based on the detection resolution and target positioning accuracy. The coordinate-corrected ultrasound dataset is assigned to corresponding three-dimensional mesh cells according to the spatial coordinate matching relationship; and Attribute fusion is performed on ultrasonic features within the same three-dimensional mesh cell.

[0046] Furthermore, the mesh granularity is determined based on the phased array ultrasonic detection resolution, beamwidth, sampling interval, target positioning accuracy, and computational constraints. For high-risk defect areas, a small-size mesh or locally refined mesh is used; for low-risk defect areas, a larger-size mesh is used to balance detection accuracy and data processing efficiency.

[0047] Furthermore, the spatial coordinate matching relationship includes: when a coordinate-corrected ultrasound data point falls within the spatial coordinate range of a certain three-dimensional grid cell, the ultrasound data point is assigned to that three-dimensional grid cell; when multiple ultrasound data points fall into the same three-dimensional grid cell, the ultrasound features of the multiple ultrasound data points are fused according to the echo signal-to-noise ratio, distance weight, or data quality identifier; when an ultrasound data point is located at the boundary of an adjacent three-dimensional grid cell, a weighted allocation is performed based on the spatial distance between the ultrasound data point and the center of the adjacent three-dimensional grid cell.

[0048] In one specific implementation, obtaining the three-dimensional reconstruction model of the defect includes: Candidate defect meshes are determined based on the ultrasonic characteristics of the workpiece substrate and the defect identification threshold. The candidate defect mesh is divided into three-dimensional connected components to obtain the defect mesh region; and The defective mesh region is subjected to boundary fitting, edge refinement, and hole filling.

[0049] Specifically, the ultrasonic characteristics of the workpiece substrate are determined based on the defect-free substrate area, standard test block, historical test data, or the normal structural area corresponding to the design model. The defect identification threshold includes echo amplitude threshold, signal attenuation threshold, phase change threshold, reflection boundary threshold, or combined feature threshold. For each three-dimensional mesh cell, a defect judgment feature value is calculated based on the difference between its ultrasonic properties and the ultrasonic characteristics of the workpiece substrate. When the defect judgment feature value meets the defect identification threshold, the corresponding three-dimensional mesh cell is determined as a candidate defect mesh.

[0050] Furthermore, the three-dimensional connected domain segmentation is used to merge spatially adjacent candidate defect meshes with ultrasonic properties that meet the defect identification conditions into the same defect mesh region, and to remove isolated noise meshes. The boundary fitting is used to generate a continuous defect outer contour based on the boundary coordinates of the defect mesh region; the edge refinement is used to correct the stepped boundaries formed by mesh discretization; and the void filling is used to fill in the internal fracture regions formed by local echo loss or insufficient sampling.

[0051] In one specific implementation, the dimensional parameters include at least one of maximum extension length, equivalent diameter, cross-sectional area, and volume; the offset is determined based on the spatial distance of the defect spatial location relative to the workpiece reference, design model reference, weld centerline, or hole axis.

[0052] In this embodiment, the spatial location of the defect is represented by the coordinate centroid of the defect mesh region, the coordinates of the defect boundary point, or the coordinates of the point with the highest defect amplitude in the three-dimensional reconstruction model of the defect. The dimensional parameters are calculated based on the spatial range of the three-dimensional reconstruction model of the defect in the global three-dimensional coordinate system of the workpiece.

[0053] Specifically, the defect mesh region is defined as including There are 3D mesh elements, and the volume of each 3D mesh element is... Then the defect volume satisfy:

[0054] in, This indicates the number of three-dimensional mesh elements in the defective mesh region. This represents the volume of a single 3D mesh cell.

[0055] When the volumes of the three-dimensional mesh elements in the defect mesh region are different, the defect volume... satisfy:

[0056] in, Indicates the first The volume of a three-dimensional mesh cell This represents the total number of three-dimensional mesh cells in the defective mesh region.

[0057] Furthermore, based on the defect volume Calculate the equivalent diameter of the defect The equivalent diameter is the diameter of a sphere with the same volume as the defect, and its calculation relationship is as follows:

[0058] The maximum extension length is the maximum spatial distance between any two boundary points in the boundary point set of the defect 3D reconstruction model; the cross-sectional area is the area of ​​the area where the defect 3D reconstruction model intersects with the preset cross-section; the offset is the spatial distance of the defect spatial position relative to the workpiece reference, the design model reference, the weld centerline, or the hole axis.

[0059] In one specific implementation, the three-dimensional imaging result includes the three-dimensional reconstruction model of the defect, the spatial coordinate label of the defect, and the defect quantization parameters.

[0060] In this embodiment, the defect 3D reconstruction model is used to display the spatial contour, extension direction and boundary morphology of the defect inside the workpiece; the defect spatial coordinate label is used to identify the position of the defect in the global 3D coordinate system of the workpiece; the defect quantification parameters include at least one of defect spatial position, maximum extension length, equivalent diameter, cross-sectional area, volume and offset.

[0061] Specifically, the three-dimensional imaging results are consistent with the global three-dimensional coordinate system of the workpiece, enabling inspectors to determine the positional relationship of the defect relative to the workpiece reference, design model reference, weld centerline, hole axis, or other quality evaluation references. Therefore, the three-dimensional imaging results are not only used to display the defect morphology but also to support workpiece defect location, dimensional assessment, and quality determination.

[0062] In one specific implementation, such as Figure 2 As shown, this embodiment takes the detection of internal defects in the weld seam of a pressure vessel as an example to illustrate the spatial coordinate calibration phased array ultrasonic three-dimensional imaging method for defects provided by the present invention.

[0063] First, detection parameters are acquired to characterize the workpiece spatial reference, probe calibration status, scanning status, and ultrasonic echo status. The workpiece spatial reference parameters include the pressure vessel bottom reference, vessel axial height, weld centerline position, weld width range, and weld thickness range. The probe calibration parameters include the number of phased array probe elements, element spacing, inherent delay, beam angle range, and wedge parameters. The scanning status parameters include the scanning trajectory, scanning point number, scanning step size, probe spatial position, and probe attitude angle. The ultrasonic echo status parameters include echo amplitude, propagation time, phase shift, signal attenuation coefficient, and reflection boundary characteristics.

[0064] Based on the workpiece spatial reference parameters, a global three-dimensional coordinate system for the workpiece is established, with the bottom surface of the pressure vessel as the XY reference plane and the height direction of the pressure vessel as the Z-axis. The coordinate boundaries of the area to be inspected are determined based on the weld centerline, weld width range, and weld thickness range. Simultaneously, a local coordinate system for the phased array probe is established, with the array center or wedge incident reference point of the phased array probe as the local coordinate origin, and the element arrangement direction, the beam incident reference direction, and the probe height direction as local coordinate axes. The coordinate transformation relationship between the phased array probe's local coordinate system and the workpiece's global three-dimensional coordinate system is determined based on the probe's initial spatial position, initial probe attitude, element parameters, beam parameters, and wedge parameters.

[0065] In this embodiment, a 64-element phased array probe is used, with an element spacing of 0.5 mm. The transverse wave velocity of the steel is set to 3200 m / s, the beam focusing depth is 5 mm to 50 mm, and the scanning angle range is 30° to 60°. Scanning points are arranged along the weld extension direction based on the coordinate boundaries, and multiple scanning tracks are set on both sides of the weld. Specifically, a first scanning track is set near the weld edge on one side of the weld, and a second scanning track is set at a preset distance from the weld edge; the corresponding scanning tracks are arranged on the other side of the weld in the same manner. For stress concentration areas, weld intersection areas, or areas with a high incidence of historical defects, the scanning point density is increased.

[0066] During phased array ultrasonic scanning, the spatial position of the phased array probe in the global three-dimensional coordinate system of the workpiece and the probe's attitude angle are acquired in real time through a laser positioning module. The coordinate transformation relationship is updated based on the real-time spatial position and attitude angle, and ultrasonic echo signals corresponding to each scanning point are collected. For each scanning point, ultrasonic features, including at least the propagation time, are extracted from the ultrasonic echo signal. Simultaneously, one or more of the following are extracted: echo amplitude, phase shift, signal attenuation coefficient, and reflection boundary features. The coordinates of the echo reflection point in the local coordinate system of the phased array probe are determined based on the propagation time, the sound velocity in the steel, and the sound beam propagation path. Then, the echo reflection point coordinates are converted into the global three-dimensional coordinates of the workpiece according to the updated coordinate transformation relationship. The ultrasonic features are then bound to the global three-dimensional coordinates of the workpiece to form an ultrasonic dataset with spatial coordinate labels.

[0067] Subsequently, the ultrasonic dataset undergoes signal preprocessing and spatial coordinate correction. Signal preprocessing includes band noise filtering, clutter suppression, and gain compensation. Band noise filtering reduces the impact of equipment and environmental noise on propagation time and peak amplitude extraction; clutter suppression eliminates invalid echoes formed by changes in coupling state, weld height reflections, and structural boundary reflections; gain compensation compensates for echo amplitude attenuation caused by increased sound path. Spatial coordinate correction determines the coordinate correction amount based on the actual sound velocity of the steel, sound wave propagation path, probe incident angle, weld curvature, and local thickness variations. This coordinate correction amount is then used to correct the spatial coordinates in the preprocessed ultrasonic dataset, resulting in a coordinate-corrected ultrasonic dataset.

[0068] Specifically, a three-dimensional spatial mesh is generated based on the coordinate boundaries of the weld area to be inspected, forming multiple three-dimensional mesh units. In this embodiment, the size of the three-dimensional mesh unit is set to 0.2mm × 0.2mm × 0.2mm. According to the spatial coordinate matching relationship, the coordinate-corrected ultrasonic data points are assigned to the corresponding three-dimensional mesh units. When multiple ultrasonic data points fall into the same three-dimensional mesh unit, attribute fusion is performed based on the echo signal-to-noise ratio, the distance between the data point and the mesh center, or the data quality identifier. This assigns the corresponding three-dimensional mesh unit echo amplitude, propagation time, phase shift, signal attenuation coefficient, and reflection boundary characteristics, forming a three-dimensional ultrasonic mesh data model of the weld area.

[0069] During defect identification, the ultrasonic characteristics of the workpiece substrate are determined based on the detection results of the defect-free weld substrate area or standard test block, and a defect identification threshold is determined based on these characteristics. The three-dimensional mesh cells in the three-dimensional ultrasonic mesh data model are traversed, and three-dimensional mesh cells with abnormal echo amplitude, abnormal attenuation, abrupt phase changes, or reflection boundary features that meet the defect identification threshold are identified as candidate defect meshes. The candidate defect meshes are then segmented into three-dimensional connected components to obtain defect mesh regions, and isolated noise meshes are removed. Boundary fitting, edge refinement, and void filling are performed on the defect mesh regions to obtain a three-dimensional reconstruction model of the weld defect. This three-dimensional defect reconstruction model is used to characterize the spatial contour and propagation direction of porosity, slag inclusions, lack of fusion, incomplete penetration, or cracks within the weld.

[0070] Finally, based on the defect 3D reconstruction model and the workpiece's global 3D coordinate system, the defect's spatial location, size parameters, offset, and 3D imaging results are output. Specifically, the defect's spatial location is determined by the centroid of the defect mesh region, the coordinates of the defect boundary points, or the coordinates of the defect's maximum echo point; the maximum extension length is determined by the maximum spatial distance between defect boundary points; the volume is determined by the number of defect meshes and the volume of a single 3D mesh unit; the equivalent diameter is calculated from the defect volume; the cross-sectional area is determined by the intersection area between the defect 3D reconstruction model and a preset cross-section; and the offset is determined by the spatial distance of the defect's spatial location relative to the weld centerline, the vessel design datum, or the workpiece datum. Thus, the 3D imaging results and defect quantification parameters of the weld defect are obtained.

[0071] In one specific embodiment, this example uses the detection of screw hole contour defects in the stationary blade edge plate of a heavy-duty gas turbine compressor to illustrate the spatial coordinate calibration phased array ultrasonic three-dimensional imaging method for defects provided by the present invention.

[0072] First, detection parameters are acquired to characterize the workpiece spatial reference, probe calibration status, scanning status, and ultrasonic echo status. The workpiece spatial reference parameters include the stationary blade assembly reference surface, the theoretical center axis of the screw hole, the end face of the hole, the standard hole diameter, the hole depth, and the theoretical profile of the hole wall. The probe calibration parameters include the phased array probe frequency, probe element parameters, wedge angle, wedge sound velocity, beam angle range, and focusing parameters. The scanning status parameters include the circumferential scanning angle, axial scanning depth, radial scanning position, scanning point number, probe spatial position, and attitude angle. The ultrasonic echo status parameters include the hole wall echo amplitude, propagation time, reflection boundary characteristics, phase shift, and signal attenuation coefficient.

[0073] Based on the workpiece spatial reference parameters, a global three-dimensional coordinate system for the workpiece is established, using the precision assembly reference surface of the stationary blade edge plate as the coordinate reference surface, the theoretical central axis of the screw hole as the Z-axis direction, and the end face of the hole as the axial starting reference. The coordinate boundaries of the area to be inspected are determined based on the standard hole diameter, hole depth, theoretical hole wall profile, and the profile area to be inspected. Simultaneously, a local coordinate system for the phased array probe is established, and the coordinate transformation relationship between the local coordinate system and the global three-dimensional coordinate system of the workpiece is determined based on the probe's initial spatial position, initial probe attitude, probe array element parameters, beam parameters, and wedge parameters. This coordinate transformation relationship is used to convert the coordinates of the hole wall echo reflection points obtained from the probe side into the contour point coordinates under the global coordinate system of the screw hole.

[0074] In this embodiment, a 5MHz large-aperture adaptive phased array probe is used, and a curved surface adapter wedge is configured. The sound velocity for detecting shear waves in alloy steel is set to 3100m / s, the sector scan angle range is 35° to 65°, the angle step is 0.1°, and the radial scan step is 7mm. Each scanning point and its corresponding probe scanning pose are determined based on the coordinate boundaries and coordinate transformation relationships of the screw hole. The scanning method combines circumferential 360° surround scanning with radial multi-channel scanning, ensuring that the scanning points cover the entire circumference and depth of the screw hole.

[0075] During phased array ultrasonic scanning, the spatial position and attitude angle of the phased array probe are acquired in real time, and the coordinate transformation relationship is updated based on the spatial position and attitude angle. For each scanning point corresponding to the circumferential angle and axial depth, ultrasonic echo signals from the hole wall substrate, hole wall contour interface, and abnormal reflection area are acquired. Ultrasonic features, including at least the propagation time, are extracted from the ultrasonic echo signals, and one or more of the following are extracted: echo amplitude, reflection boundary features, phase shift, and signal attenuation coefficient. The coordinates of the echo reflection point in the local coordinate system of the phased array probe are determined based on the propagation time, the sound velocity of the alloy steel material, and the sound beam propagation path. Then, the echo reflection point coordinates are converted into the global three-dimensional coordinates of the workpiece according to the updated coordinate transformation relationship, and the ultrasonic features are bound to the global three-dimensional coordinates of the workpiece to form a screw hole contour ultrasonic dataset with spatial coordinate labels.

[0076] Subsequently, the ultrasonic dataset of the screw hole contour is subjected to signal preprocessing and spatial coordinate correction. The signal preprocessing includes adaptive band noise filtering, structural clutter suppression, and path gain compensation. Adaptive band noise filtering preserves the echoes from the hole wall contour interface and reduces the influence of material structure noise; structural clutter suppression eliminates invalid reflections formed by the hole edge, curved transition zone, and assembly boundary; and path gain compensation compensates for differences in sound path at different circumferential angles and hole depths. Spatial coordinate correction determines the coordinate correction amount based on the cylindrical curved surface structure of the screw hole, the workpiece surface normal, the probe incident angle, wedge parameters, curvature changes, and hole depth thickness changes. This coordinate correction amount is then used to correct the spatial coordinates in the preprocessed ultrasonic dataset, resulting in the coordinate-corrected ultrasonic dataset of the screw hole contour.

[0077] Specifically, a three-dimensional spatial mesh is formed based on the coordinate boundaries of the screw hole inspection area, creating multiple three-dimensional mesh units. In this embodiment, the size of the three-dimensional mesh unit is set to 0.12mm × 0.12mm × 0.12mm. According to the spatial coordinate matching relationship, the coordinate-corrected contour ultrasonic data points are assigned to the corresponding three-dimensional mesh units. When multiple contour data points fall into the same three-dimensional mesh unit, attribute fusion is performed according to data quality identifiers, echo signal-to-noise ratio, or spatial distance weights. This assigns ultrasonic attributes such as echo amplitude, propagation duration, reflection boundary characteristics, and phase shift to the three-dimensional mesh unit, forming a three-dimensional ultrasonic mesh data model of the screw hole contour area.

[0078] During defect identification, the ultrasonic characteristics of the workpiece substrate are determined based on the standard theoretical contour of the screw hole, the defect-free hole wall region, or the test results of a standard test block. The defect identification threshold is then determined by combining the contour deviation range. Candidate defect meshes are determined based on the differences between the ultrasonic properties of each 3D mesh unit in the 3D ultrasonic mesh data model and the ultrasonic characteristics of the workpiece substrate. The candidate defect meshes are then segmented into 3D connected components to obtain defect mesh regions. These defect mesh regions correspond to one or more abnormal areas, including local hole wall collapse, contour eccentricity, uneven wall thickness, grinding grooves, or local defects. Boundary fitting, edge refinement, and void filling are performed on the defect mesh regions to obtain a 3D reconstruction model of the screw hole contour defect.

[0079] Finally, based on the 3D reconstruction model of the screw hole contour defect and the workpiece's global 3D coordinate system, the spatial location, dimensional parameters, offset, and 3D imaging results of the defect are output. Specifically, the spatial location of the defect is determined by the spatial coordinates of the defect mesh region relative to the theoretical central axis of the screw hole, the end face of the hole, and the assembly reference surface; the maximum extension length is determined by the maximum spatial distance between the defect boundary points; the cross-sectional area is determined by the intersection area of ​​the defect's 3D reconstruction model on the axial or circumferential cross-section; the volume is determined by the number of defect meshes and the unit volume; the equivalent diameter is calculated based on the volume; and the offset is determined by the spatial distance of the defect's spatial location relative to the theoretical central axis of the screw hole, the standard theoretical contour of the hole wall, or the assembly reference surface. Thus, the 3D imaging results and contour quantization parameters of the screw hole contour defect are obtained.

[0080] In summary, this embodiment has at least the following technical effects: This invention establishes a global three-dimensional coordinate system for the workpiece by acquiring detection parameters used to characterize the workpiece's spatial reference, probe calibration status, scanning status, and ultrasonic echo status, and determines the coordinate transformation relationship between the phased array probe's local coordinate system and the workpiece's global three-dimensional coordinate system. This enables the phased array ultrasonic detection results to have a unified spatial coordinate reference, avoiding coordinate deviations caused by traditional detection methods that rely solely on sound path, scanning angle, or two-dimensional cross-sectional images for relative positioning. This invention determines the probe scanning pose corresponding to each scanning point based on the coordinate boundary and coordinate transformation relationship of the area to be detected, and updates the coordinate transformation relationship according to the real-time spatial position and attitude angle of the probe during the phased array ultrasonic scanning process, so that the probe movement, attitude deflection and scanning trajectory change can be reflected in the workpiece spatial position corresponding to the ultrasonic echo signal, thereby improving the correspondence accuracy between ultrasonic echo data and the actual spatial position of the workpiece. This invention binds ultrasonic features extracted from ultrasonic echo signals, such as echo amplitude, propagation time, phase shift, signal attenuation coefficient, and reflection boundary features, to the corresponding global three-dimensional coordinates of the workpiece, forming an ultrasonic dataset with spatial coordinate labels. This transforms discrete ultrasonic inspection data from traditional two-dimensional image data into spatial coordinate-based inspection data, providing a data foundation for subsequent three-dimensional mesh modeling, defect segmentation, and parameter quantization. This invention performs signal preprocessing and spatial coordinate correction on ultrasonic datasets with spatial coordinate labels. It improves the stability of effective defect echo characteristics through noise filtering, clutter suppression, and gain compensation. The coordinate correction amount is determined based on the sound velocity of the workpiece material, the sound wave propagation path, the probe incident angle, and the workpiece curvature or thickness variation, thereby reducing the impact of sound velocity deviation, beam refraction, surface deformation, and thickness variation on defect spatial positioning. This invention performs three-dimensional spatial meshing based on the coordinate boundaries of the area to be detected, and maps the coordinate-corrected ultrasound dataset to the corresponding three-dimensional mesh unit to form a three-dimensional ultrasound mesh data model. This enables discrete ultrasound data formed by multi-channel and multi-angle phased array scanning to be fused in a unified three-dimensional space, solving the problems of fragmented traditional detection data and difficulty in correlation between different scanning sections. This invention identifies defect meshes based on a three-dimensional ultrasonic mesh data model and reconstructs the three-dimensional morphology of the defect meshes. It can restore the spatial contour, extension direction and boundary morphology of defects in the global three-dimensional coordinate system of the workpiece. It is suitable for three-dimensional representation of irregular defects such as cracks, pores, slag inclusions, lack of fusion, incomplete penetration, hole wall collapse, and grooves. This invention outputs the spatial location, size parameters, offset, and three-dimensional imaging results of defects based on the three-dimensional reconstruction model of the defects and the global three-dimensional coordinate system of the workpiece. This makes the detection results include not only the defect display image, but also the maximum extension length, equivalent diameter, cross-sectional area, volume, and offset relative to the workpiece reference, design model reference, weld centerline, or hole axis, which facilitates workpiece quality assessment, defect tracing, and maintenance decision-making.

[0081] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A spatial coordinate calibration-based phased array ultrasonic defect three-dimensional imaging method, characterized in that, Includes the following steps: S1: Acquire detection parameters used to characterize the workpiece spatial reference, phased array probe calibration status, scanning status, and ultrasonic echo status; S2: Establish a global three-dimensional coordinate system for the workpiece based on the detection parameters, determine the coordinate boundaries of the area to be detected, and determine the coordinate transformation relationship between the local coordinate system of the phased array probe and the global three-dimensional coordinate system of the workpiece; S3: Based on the coordinate boundary and the coordinate transformation relationship, determine the scanning pose of each scanning point and the corresponding phased array probe. During phased array ultrasonic scanning, update the coordinate transformation relationship according to the real-time spatial position and attitude angle of the phased array probe, collect the ultrasonic echo signal corresponding to each scanning point, and bind the ultrasonic features extracted from the ultrasonic echo signal to the corresponding global three-dimensional coordinates of the workpiece according to the updated coordinate transformation relationship to form an ultrasonic dataset with spatial coordinate labels. S4: Perform signal preprocessing and spatial coordinate correction on the ultrasound dataset to obtain a coordinate-corrected ultrasound dataset. Then, perform three-dimensional spatial meshing on the area to be detected according to the coordinate boundaries to form multiple three-dimensional mesh units. Map the coordinate-corrected ultrasound dataset to the corresponding three-dimensional mesh units to form a three-dimensional ultrasound mesh data model. S5: Identify the defect mesh based on the three-dimensional ultrasonic mesh data model, and reconstruct the three-dimensional morphology of the defect mesh to obtain a three-dimensional reconstruction model of the defect. S6: Based on the defect 3D reconstruction model and the workpiece global 3D coordinate system, output the defect spatial location, size parameters, offset, and 3D imaging results.

2. The spatial coordinate calibration phased array ultrasonic defect three-dimensional imaging method according to claim 1, characterized in that, The detection parameters include workpiece spatial reference parameters, probe calibration parameters, scanning status parameters, and ultrasonic echo status parameters. The workpiece spatial reference parameters include the boundary parameters of the area to be detected.

3. The spatial coordinate calibration phased array ultrasonic defect three-dimensional imaging method according to claim 1, characterized in that, Establishing the global three-dimensional coordinate system of the workpiece includes: The coordinate datum is determined based on the workpiece's geometric datum, assembly datum, design model, or 3D scanning model; and The coordinate boundary is determined based on the coordinate reference and the spatial range of the area to be detected.

4. The spatial coordinate calibration phased array ultrasonic defect three-dimensional imaging method according to claim 1, characterized in that, Determining the coordinate transformation relationship includes: Establish the local coordinate system of the phased array probe; and determine the coordinate transformation relationship composed of rotation and translation relationships based on the probe's initial spatial position, initial probe attitude, probe array element parameters, beam parameters, and wedge parameters.

5. The spatial coordinate calibration phased array ultrasonic defect three-dimensional imaging method according to claim 1, characterized in that, The ultrasound dataset with spatial coordinate labels includes: At least one of the following, namely propagation duration, echo amplitude, phase shift, signal attenuation coefficient, and reflection boundary features, is extracted from the ultrasonic echo signal as the ultrasonic feature; The coordinates of the echo reflection point in the local coordinate system of the phased array probe are determined based on the propagation duration, the sound velocity of the workpiece material, and the sound beam propagation path. Based on the updated coordinate transformation relationship, the coordinates of the echo reflection point are converted into the global three-dimensional coordinates of the workpiece; and The scanning point number, probe spatial position, probe attitude angle, beam parameters, ultrasonic features, and global three-dimensional coordinates of the workpiece corresponding to the same scanning point are associated and stored to form an ultrasonic data record with spatial coordinate labels. Multiple ultrasonic data records are then used to form the ultrasonic dataset with spatial coordinate labels.

6. The spatial coordinate calibration phased array ultrasonic defect three-dimensional imaging method according to claim 1, characterized in that, The signal preprocessing includes at least one of noise filtering, clutter suppression, and gain compensation; the spatial coordinate correction includes determining the coordinate correction amount based on the sound velocity of the workpiece material, the sound wave propagation path, the probe incident angle, the curvature or thickness change of the workpiece, and using the coordinate correction amount to correct the spatial coordinates in the ultrasonic data set after the signal preprocessing.

7. The spatial coordinate calibration phased array ultrasonic defect three-dimensional imaging method according to claim 1, characterized in that, The formation of the three-dimensional ultrasound mesh data model includes: The mesh division granularity is determined based on the detection resolution and target positioning accuracy. The coordinate-corrected ultrasound dataset is assigned to corresponding three-dimensional mesh cells according to the spatial coordinate matching relationship; and Attribute fusion is performed on ultrasonic features within the same three-dimensional mesh cell.

8. The spatial coordinate calibration phased array ultrasonic defect three-dimensional imaging method according to claim 1, characterized in that, The obtained three-dimensional reconstruction model of the defect includes: Candidate defect meshes are determined based on the ultrasonic characteristics of the workpiece substrate and the defect identification threshold. The candidate defect mesh is divided into three-dimensional connected components to obtain the defect mesh region; and The defective mesh region is subjected to boundary fitting, edge refinement, and hole filling.

9. The spatial coordinate calibration phased array ultrasonic defect three-dimensional imaging method according to claim 1, characterized in that, The dimensional parameters include at least one of the maximum extension length, equivalent diameter, cross-sectional area, and volume; the offset is determined based on the spatial distance of the defect spatial location relative to the workpiece reference, design model reference, weld centerline, or hole axis.

10. The spatial coordinate calibration phased array ultrasonic defect three-dimensional imaging method according to any one of claims 1 to 9, characterized in that, The three-dimensional imaging results include the three-dimensional reconstruction model of the defect, the spatial coordinate labels of the defect, and the defect quantization parameters.

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