Phase-controlled imaging system and method for crimping fitting

Abstract

The invention discloses a phase-controlled imaging system and method for a crimping fitting. The phase control imaging system of the crimping fitting comprises an arc-shaped phased array probe which is used for fitting a curved surface structure of the crimping fitting, transmitting an ultrasonic signal to the crimping fitting and receiving an echo signal returned from the crimping fitting; the signal acquisition and processing module is connected with the arc-shaped phased array probe, and the signal acquisition and processing module is used for acquiring the echo signal acquired by the arc-shaped phased array probe, generating a three-dimensional acoustic image of the crimping fitting according to the echo signal, and identifying the defect of the crimping fitting in the three-dimensional acoustic image to obtain a defect detection result; and the interaction terminal is connected with the signal acquisition and processing module and is used for displaying the three-dimensional acoustic image and the defect detection result. According to the invention, the imaging accuracy of the crimping fitting can be improved, so that the diagnosis of defects in the crimping fitting is realized.

Description

Technical Field

[0001] The present invention relates to the field of detection technology, and in particular to a phased array imaging system and method for crimp fittings. Background Technology

[0002] Transmission line fittings (such as tension clamps and splicing tubes) are key components for ensuring the safe operation of transmission lines. Their internal defects (such as broken conductor strands, crimp cavities, and cracks) can easily lead to major accidents.

[0003] Currently, ultrasonic phased array technology is one of the main methods for detecting internal defects in such hardware. However, existing detection technologies are generally based on time-domain full-focusing algorithms, and traditional planar probes are difficult to fit well with the curved surfaces of hardware, resulting in low acoustic coupling efficiency. Furthermore, time-domain interpolation algorithms are prone to introducing the picket fence effect, leading to insufficient image resolution, high failure rate for small defects, and a lack of intelligent diagnostic functions. They also rely heavily on the experience and judgment of the inspectors, resulting in low defect detection efficiency and high subjectivity. Summary of the Invention

[0004] This invention provides a phased array imaging system and method for press-fit fittings to improve the accuracy of press-fit fitting imaging, thereby enabling the diagnosis of defects in press-fit fittings.

[0005] In a first aspect, embodiments of the present invention provide a phased array imaging system for press-fit fittings, comprising:

[0006] An arc-shaped phased array probe is used to fit the curved surface structure of the crimping fitting, and to emit ultrasonic signals to the crimping fitting and receive echo signals returned from the crimping fitting.

[0007] A signal acquisition and processing module is connected to the arc-shaped phased array probe. The signal acquisition and processing module is used to acquire the echo signal acquired by the arc-shaped phased array probe, generate a three-dimensional acoustic image of the crimping hardware based on the echo signal, identify the defects of the crimping hardware in the three-dimensional acoustic image, and obtain the defect detection result.

[0008] An interactive terminal, connected to the signal acquisition and processing module, is used to display the three-dimensional acoustic image and the defect detection results.

[0009] Optionally, the arc-shaped phased array probe comprises 32 arc-shaped phased array elements, and the spacing between adjacent arc-shaped phased array elements is a preset distance.

[0010] Optionally, the radius of curvature of the arc-shaped phased array element is 6.9-7.1 mm, the operating frequency band of the arc-shaped phased array element is 1-9 MHz, and the material of the arc-shaped phased array element is lead zirconate titanate piezoelectric ceramic.

[0011] Optionally, the preset distance is λ / 2, where λ is the wavelength of the ultrasonic signal emitted by the arc-shaped phased array probe.

[0012] Optionally, the signal acquisition and processing module includes:

[0013] The acquisition unit is connected to the arc-shaped phased array probe, and the acquisition module is used to acquire the echo signal acquired by the arc-shaped phased array probe;

[0014] The processing unit has its input terminal connected to the acquisition unit and the interactive terminal. The processing unit is used to generate a three-dimensional acoustic image of the crimping fitting based on the echo signal, identify defects in the crimping fitting in the three-dimensional acoustic image, and obtain defect detection results.

[0015] Optionally, the phased array imaging system of the press-fit fitting also includes a built-in battery;

[0016] The built-in battery is connected to the arc-shaped phased array probe, the signal acquisition and processing module, and the interactive terminal. The built-in battery is used to power the arc-shaped phased array probe, the signal acquisition and processing module, and the interactive terminal.

[0017] Secondly, embodiments of the present invention also provide a phased array imaging method for press-fit fittings, wherein the phased array imaging method for press-fit fittings is applied to the phased array imaging system for press-fit fittings described in any embodiment of the present invention, and the phased array imaging method for press-fit fittings includes:

[0018] The echo signal acquired by the arc-shaped phased array probe is obtained;

[0019] A three-dimensional acoustic image of the crimping fitting is generated based on the echo signal, and defects in the crimping fitting in the three-dimensional acoustic image are identified to obtain defect detection results.

[0020] Optionally, the echo signal acquired by the arc-shaped phased array probe is full matrix data, and the step of generating a three-dimensional acoustic image of the crimping fitting based on the echo signal includes:

[0021] Perform a three-dimensional fast Fourier transform on the full matrix data to convert the time-domain signal to the frequency domain, thus obtaining frequency-domain data;

[0022] In the wavenumber domain, the geometric error of the crimping fitting in the frequency domain data is corrected by an arc sphere compensation factor, and the acoustic wave scattering effect at the multi-material interface in the crimping fitting in the frequency domain data is compensated by a phononic crystal bandgap correction term.

[0023] The compensated frequency domain data is reconstructed by hybrid interpolation to generate the three-dimensional acoustic image.

[0024] Optionally, the step of using a phononic crystal bandgap correction term to compensate for the acoustic wave scattering effect at the multi-material interface in the press-fit fitting in the frequency domain data includes:

[0025] The phononic crystal bandgap correction term is generated based on the material interface scattering coefficient and acoustic wave propagation delay at the multi-material interface in the press-fit fitting.

[0026] The acoustic wave scattering effect at the multi-material interface in the press-fit fitting is compensated by the phonon crystal bandgap correction term.

[0027] Optionally, defects in the crimping fitting in the three-dimensional acoustic image are identified to obtain defect detection results, including:

[0028] The defects of the crimping fitting in the three-dimensional acoustic image are identified by a deep learning network model to obtain the defect detection result; wherein, the defect detection result includes a set of parameters that quantitatively describe the defect characteristics, the set of parameters that quantitatively describe the defect characteristics includes scattering amplitude, phase shift, and shape factor, the scattering amplitude is the intensity of the echo at the defect in the crimping fitting, the phase shift is the phase difference between the echo at the defect in the crimping fitting and the echo in the normal area of ​​the crimping fitting, and the shape factor is the geometric parameter at the defect in the crimping fitting.

[0029] This invention provides a phased array imaging system and method for press-fit fittings. The phased array imaging system for press-fit fittings includes an arc-shaped phased array probe that conforms to the curved surface structure of the press-fit fitting, emits ultrasonic signals to the fitting, and receives echo signals returned from the fitting. A signal acquisition and processing module is connected to the arc-shaped phased array probe. This module acquires the echo signals from the probe, generates a three-dimensional acoustic image of the press-fit fitting based on the echo signals, identifies defects in the three-dimensional acoustic image, and obtains defect detection results. An interactive terminal, connected to the signal acquisition and processing module, displays the three-dimensional acoustic image and defect detection results. This invention improves the accuracy of press-fit fitting imaging, thereby enabling the diagnosis of defects in press-fit fittings. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of a phased array imaging system for a press-fit fitting provided in an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the structure of another phase-array imaging system for a press-fit fitting provided in an embodiment of the present invention;

[0032] Figure 3A flowchart of a phased array imaging method for a press-fit fitting provided in an embodiment of the present invention;

[0033] Figure 4 A flowchart of another phase-array imaging method for press-fit fittings provided in an embodiment of the present invention;

[0034] Figure 5 A flowchart of another phase-array imaging method for press-fit fittings provided in an embodiment of the present invention. Detailed Implementation

[0035] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0036] Figure 1 This is a schematic diagram of a phased array imaging system for a press-fit fitting provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the phased array imaging system for the crimp fitting includes: an arc-shaped phased array probe 110, which is used to fit the curved structure of the crimp fitting, transmit ultrasonic signals to the crimp fitting, and receive echo signals returned from the crimp fitting.

[0037] The signal acquisition and processing module 120 is connected to the arc-shaped phased array probe 110. The signal acquisition and processing module 120 is used to acquire the echo signal acquired by the arc-shaped phased array probe 110, generate a three-dimensional acoustic image of the crimping hardware based on the echo signal, identify the defects of the crimping hardware in the three-dimensional acoustic image, and obtain the defect detection result.

[0038] The interactive terminal 130 is connected to the signal acquisition and processing module 120 and is used to display three-dimensional acoustic images and defect detection results.

[0039] Among them, crimp fittings are key components used in high-voltage transmission lines for permanently connecting or fixing conductors. Crimping fittings can connect two sections of conductors to ensure the smooth flow of current. Internal defects (such as broken conductor strands, crimp cavities, and cracks) can easily lead to major accidents. The surface of the crimp fitting is curved, which can be called a curved structure. To fit the curved structure of the crimp fitting, a clearer detection image can be obtained. The arc phased array probe 110 can be composed of multiple arc arrays. The arc phased array probe 110 can fit the curved structure of the crimp fitting and emit ultrasonic signals to the crimp fitting, and receive the echo signals returned from the crimp fitting. The echo signals are used to form a three-dimensional acoustic image.

[0040] Specifically, the arc-shaped phased array probe 110 can conform to the curved surface structure of the crimping fitting, such as the curved surface structure of the tension clamp of the crimping fitting, improving the acoustic coupling efficiency to 90% and reducing the edge blind zone. During operation, the arc-shaped phased array probe 110 emits ultrasonic signals to the crimping fitting and receives the echo signals returned from the crimping fitting. The signal acquisition and processing module 120 is connected to the arc-shaped phased array probe 110. The signal acquisition and processing module 120 can acquire the echo signals acquired by the arc-shaped phased array probe 110. Based on the frequency domain algorithm, it generates a three-dimensional acoustic image of the crimping fitting according to the echo signals. For example, the frequency domain algorithm can convert the acquired time domain signal to the frequency domain, improve the processing speed, and introduce a phonon crystal bandgap correction term Δ(ω) to accurately compensate for the influence of sound wave scattering at the multi-material interface on the sound pressure field calculation, correct the sound wave propagation characteristics, suppress scattering noise, effectively solve the imaging problem caused by the multi-material interface, and improve the accuracy of sound field modeling and the realism of imaging. The signal acquisition and processing module 120 can also identify defects in crimp fittings in the three-dimensional acoustic image and obtain defect detection results. For example, a model that can identify defects in crimp fittings can be formed based on a deep learning network, thereby automatically identifying and classifying defects in crimp fittings. The interactive terminal 130 is connected to the signal acquisition and processing module 120. The interactive terminal 130 can be a display device that can display three-dimensional acoustic images and defect detection results to quickly detect defects in crimp fittings, reduce human interference, improve the objectivity, accuracy, and automation level of detection, provide a scientific basis for defect handling decisions, and thus provide strong protection for the safe operation of transmission lines.

[0041] This invention provides a phased array imaging system for press-fit fittings. The system includes an arc-shaped phased array probe that conforms to the curved surface of the press-fit fitting, emitting ultrasonic signals and receiving echo signals from it. A signal acquisition and processing module is connected to the arc-shaped phased array probe, acquiring the echo signals and generating a three-dimensional acoustic image of the press-fit fitting based on the echo signals. The module also identifies defects in the three-dimensional acoustic image, obtaining defect detection results. An interactive terminal, connected to the signal acquisition and processing module, displays the three-dimensional acoustic image and defect detection results, improving the accuracy of the press-fit fitting imaging and enabling the diagnosis of defects in the press-fit fitting.

[0042] In some embodiments of the present invention, the arc-shaped phased array probe 110 includes 32 arc-shaped phased array elements, and the spacing between adjacent arc-shaped phased array elements is a preset distance.

[0043] Specifically, the 32-element arc-shaped phased array consists of 32 arc-shaped phased array elements arranged in an arc shape, forming the arc-shaped phased array probe 110. The arc-shaped phased array elements have a certain radius of curvature to conform to the curved surface structure of the pressure fitting, increasing the acoustic coupling efficiency from 30% to 90%. The spacing between adjacent arc-shaped phased array elements is a preset distance to effectively suppress grating lobe interference and improve beam directivity.

[0044] Existing technologies employ planar phased array probes, while transmission line fittings (such as tension clamps) are mostly curved structures (radius of curvature ≈ 7mm), resulting in air gaps between the probe and the fitting surface, leading to acoustic wave reflection losses exceeding 60%. Furthermore, the excessively large incident angle of the acoustic beam from the edge elements fails to cover the inner area of ​​the fitting, creating blind spots. Defects in the curved transition zone of the fitting and deep defects at the crimping interface are difficult to detect, and repeatability is poor. The unstable fit of the probe when manually held results in significant differences between different batches. In contrast, the arc-shaped phased array probe 110 in this invention comprises 32 arc-shaped phased array elements, which can conform to the curved structure of the crimping fitting, adapting to different defect sizes and depths, thus facilitating defect detection.

[0045] Furthermore, the 32-element arc-shaped phased array element achieves beam focusing, scanning, and deflection through electronic control of the excitation timing of each element. Its radius of curvature (7±0.1mm) conforms to the curved surface structure of voltage transmission fittings (such as the arc structure of tension clamps), reducing acoustic coupling loss. The element material is lead zirconate titanate piezoelectric ceramic, which has a high electromechanical coupling coefficient and stability, suitable for wide-bandwidth (1-9MHz) detection. Compared to a single probe, the 32-element arc-shaped phased array element can emit sound waves from multiple angles, covering blind areas of complex structures and improving defect detection coverage.

[0046] Optionally, the radius of curvature of the arc-shaped phased array element is 6.9-7.1mm, the operating frequency band of the arc-shaped phased array element is 1-9MHz, and the material of the arc-shaped phased array element is lead zirconate titanate piezoelectric ceramic.

[0047] Specifically, each arc-shaped phased array element has a radius of curvature of 6.9-7.1 mm to tightly press against curved structures such as tension clamps and other fittings. The arc-shaped phased array element operates in the 1-9 MHz frequency band, providing a wide 1-9 MHz response to accommodate different defect sizes and depths. The arc-shaped phased array element is made of PZT-5H piezoelectric material, specifically lead zirconate titanate piezoelectric ceramic.

[0048] The 110 wideband 1-9MHz arc-shaped phased array probe can emit ultrasonic waves of different frequencies, adapting to the detection of different defect sizes and depths. Simultaneously, a hybrid interpolation algorithm combining 7th-order sinc kernel interpolation and Catmull-Rom spline interpolation improves image resolution. The wideband probe enhances the ability to capture weak defect echoes. The hybrid interpolation algorithm improves the axial resolution to 0.35mm and the lateral resolution to 0.75mm, enabling the detection of minute strand breakage defects as small as 0.7mm. The signal-to-noise ratio is improved to over 12dB, effectively solving the problem of missed detection of minute defects in traditional methods and improving the reliability of detection.

[0049] Optionally, the preset distance is λ / 2, where λ is the wavelength of the ultrasonic signal emitted by the arc-shaped phased array probe 110.

[0050] Specifically, the preset distance between the arc phased array elements is λ / 2, where λ is the wavelength of the ultrasonic signal emitted by the arc phased array probe 110. For example, when the arc phased array probe 110 operates at a frequency of 5MHz, the preset distance between the arc phased array elements is approximately 0.3mm, which effectively suppresses grating lobe interference and improves beam directivity.

[0051] Figure 2 This is a schematic diagram of the structure of another phased array imaging system for press-fit fittings provided in an embodiment of the present invention, as shown below. Figure 2 As shown, in some embodiments of the present invention, the signal acquisition and processing module 120 includes: an acquisition unit 121 connected to the arc-shaped phased array probe 110, the acquisition module 121 being used to acquire the echo signal acquired by the arc-shaped phased array probe 110; and a processing unit 122, the input end of the processing unit 122 being connected to the acquisition unit 121 and the input end of the processing unit 122 being connected to the interactive terminal 130, the processing unit 122 being used to generate a three-dimensional acoustic image of the crimping fitting based on the echo signal, and to identify defects in the crimping fitting in the three-dimensional acoustic image, thereby obtaining defect detection results.

[0052] The acquisition unit 121 can utilize the AD7606 chip to achieve 16-bit, 100MS / s high-speed sampling. Combined with a programmable gain amplifier (PGA), the dynamic range reaches 90dB, accurately capturing weak defect echoes and strong interface reflection signals. Alternatively, the acquisition unit 121 can use a PCIe-based or embedded data acquisition card with a sampling rate of 50-100MS / s and a dynamic range of 80-90dB. The processing unit 122 can utilize a general-purpose computer or DSP processor, relying on CPU serial computation. Alternatively, the processing unit 122 can use a Xilinx Zynq MPSoC integrating an ARM processor and FPGA logic. The ARM processor is responsible for system control, data scheduling, and algorithm flow management; the FPGA, through a hardware acceleration module, implements key algorithms such as FFT transformation and wavenumber domain computation, achieving a speedup of over 20 times compared to pure software implementation. Combined with an NVIDIA Jetson GPU and utilizing the CUDA parallel computing architecture, it further accelerates the frequency domain full-focusing algorithm, reducing the single-frame processing time from 18 seconds to 0.28 seconds. The interactive terminal 130 can be equipped with a 7-inch high-resolution touch screen and an integrated 3D rendering engine developed based on VTK (Visualization Tool kit) to render 3D acoustic images in real time. It can intuitively display the position, shape and quantization parameters of each structure in the 3D acoustic image, and supports gesture operation, which is convenient for on-site interaction by inspection personnel.

[0053] Specifically, the acquisition module 121 acquires the echo signal obtained by the arc-shaped phased array probe 110 at high speed; the processing unit 122 generates a three-dimensional acoustic image of the crimp fitting based on the echo signal, identifies defects in the crimp fitting in the three-dimensional acoustic image, and obtains the defect detection result; the interactive terminal 130 displays the three-dimensional acoustic image of the crimp fitting and the defect detection result in real time, realizing human-computer interaction, facilitating the rapid detection of defects in the crimp fitting by inspection personnel, reducing human interference, improving the objectivity, accuracy and automation level of the inspection, providing a scientific basis for defect handling decisions, and thus providing a strong guarantee for the safe operation of transmission lines.

[0054] Furthermore, the processing unit 122 can utilize a Xilinx Zynq Ultra Scale+ MPSoC chip, integrating a hybrid architecture of an ARM processor (responsible for logic control) and FPGA programmable logic (responsible for parallel computing). The ARM processor runs a real-time operating system, coordinating probe control, data transmission, and software algorithm processes. The FPGA handles hardware-accelerated computationally intensive tasks such as frequency domain transformation and wavenumber shifting, achieving a real-time imaging speed of 0.28s / frame in conjunction with a GPU acceleration module. This approach balances computational efficiency with system flexibility, meeting the low-power and real-time requirements of field environments.

[0055] In some embodiments of the present invention, such as Figure 3As shown, the phased array imaging system of the press fitting also includes a built-in battery 140; the built-in battery 140 is connected to the arc phased array probe 110, the signal acquisition and processing module 120 and the interactive terminal 130, and the built-in battery 140 is used to power the arc phased array probe 110, the signal acquisition and processing module 120 and the interactive terminal 130.

[0056] Specifically, the signal acquisition and processing module 120 adopts an integrated design, integrated onto a four-layer PCB board. The PCB board uses a 50Ω impedance matching design to reduce signal transmission loss. The built-in battery 140 can be a built-in lithium battery pack with specifications of 48V / 10Ah. Together with the power management chip, it powers the arc-shaped phased array probe 110, the signal acquisition and processing module 120, and the interactive terminal 130, providing a battery life of over 4 hours, meeting the needs of field operations in environments without power. Addressing the problem of poor adaptability to field environments in existing imaging equipment, such as the bulky nature of X-ray inspection equipment (>50kg) and the difficulty of adapting conventional ultrasonic inspection equipment to complex field environments, the phased array imaging system for pressure fittings in this embodiment of the invention adopts a portable hardware design. The arc-shaped phased array probe 110 and the signal acquisition and processing module 120 are small in size and lightweight; the interactive terminal 130 has a user-friendly interface, is easy to operate, and has successfully identified multiple hidden defects in practical applications, demonstrating strong adaptability and reliability in field environments.

[0057] This invention also provides a phased array imaging method for press-fit fittings. This method is applied to the signal acquisition and processing module of the phased array imaging system for press-fit fittings in this invention. Figure 3 A flowchart of a phased array imaging method for a press-fit fitting provided in an embodiment of the present invention is shown below. Figure 3 As shown, the phased array imaging method for press-fit fittings includes:

[0058] S110. Acquire the echo signal obtained by the arc phased array probe.

[0059] S120. Generate a three-dimensional acoustic image of the crimping fitting based on the echo signal, identify defects in the crimping fitting in the three-dimensional acoustic image, and obtain defect detection results.

[0060] refer to Figure 1In steps S110-S120, by acquiring the echo signal obtained by the arc-shaped phased array probe 110, a three-dimensional acoustic image of the press-fit fitting is generated based on the frequency domain algorithm. For example, the frequency domain algorithm can convert the acquired time-domain signal to the frequency domain, improving processing speed, and introduces a phonon crystal bandgap correction term Δ(ω) to accurately compensate for the influence of sound wave scattering at multi-material interfaces on the sound pressure field calculation, correcting sound wave propagation characteristics, suppressing scattering noise, effectively solving the imaging problem caused by multi-material interfaces, and improving the accuracy of sound field modeling and the realism of imaging. Based on the formed three-dimensional acoustic image, defects in the press-fit fitting can be identified, and defect detection results can be obtained. For example, a model that can identify defects in the press-fit fitting can be formed based on a deep learning network, thereby automatically identifying and classifying defects in the press-fit fitting. The interactive terminal 130 is connected to the signal acquisition and processing module 120. The interactive terminal 130 can be a display device that can display three-dimensional acoustic images and defect detection results, so as to quickly detect defects in crimp fittings, reduce human interference, improve the objectivity, accuracy and automation level of detection, provide a scientific basis for defect handling decisions, and thus provide a strong guarantee for the safe operation of transmission lines.

[0061] This invention provides a phased array imaging method for crimp fittings. By acquiring echo signals from an arc-shaped phased array probe, a three-dimensional acoustic image of the crimp fitting is generated based on the echo signals. Defects in the crimp fitting are then identified in the three-dimensional acoustic image, and defect detection results are obtained. This method enables the diagnosis of defects in crimp fittings, reduces human interference, improves the objectivity, accuracy, and automation of detection, provides a scientific basis for defect handling decisions, and thus provides strong protection for the safe operation of transmission lines.

[0062] This invention also provides another phased array imaging method for press-fit fittings, wherein the echo signal acquired by the arc-shaped phased array probe is full matrix data. Figure 4 A flowchart of another phase-array imaging method for press-fit fittings provided in an embodiment of the present invention is shown below. Figure 4 As shown, the phased array imaging method for press-fit fittings includes...

[0063] S210. Acquire the echo signal obtained by the arc phased array probe.

[0064] S220. Perform a three-dimensional fast Fourier transform on the full matrix data to convert the time-domain signal to the frequency domain and obtain frequency-domain data.

[0065] In this embodiment of the invention, the arc-shaped phased array probe 110 transmits a 5MHz center frequency pulse modulated by a 3-cycle Hanning window, and the 32 array elements are excited sequentially. It receives the full matrix 32×32 channel echo, collects data for 4096 points, and constructs a 32×32×4096 full matrix dataset to completely record the internal acoustic field information of the crimping hardware. That is, the echo signal acquired by the arc-shaped phased array probe 110 is full matrix data.

[0066] Specifically, in this embodiment of the invention, a frequency-domain full-focusing algorithm is used to construct a three-dimensional acoustic image. This algorithm is an imaging technique based on ultrasonic phased array technology. By processing the full matrix data acquired from multiple array elements in the frequency domain, it achieves focused imaging of internal defects in the detected object. The principle of the frequency-domain full-focusing algorithm is as follows: the time-domain ultrasonic signal is converted to the frequency domain via Fourier transform. Using wavenumber domain sound field migration calculation and focusing algorithms, the phase difference of sound waves along different paths is compensated, enabling coherent superposition of echo signals from the defect in the frequency domain, thereby improving imaging resolution and signal-to-noise ratio. Compared to the traditional time-domain full-focusing algorithm (TD-FMC), frequency-domain processing significantly reduces computational complexity, improves real-time performance, and reduces picket fence error, with a single-frame processing time of only 0.28 seconds.

[0067] In existing technologies, the computational complexity of the time-domain full-focusing algorithm is O(N). 2 (WH) (N is the number of array elements, W is the imaging width, and H is the imaging height). Taking 512×512 pixel imaging as an example, the processing time for a single frame exceeds 18 seconds, which cannot meet the needs of real-time on-site detection. Moreover, it relies on CPU serial calculation, making it difficult to handle real-time processing of large amounts of data. In addition, the temporal domain full-focusing algorithm relies on interpolation reconstruction of discrete sampled data. Traditional interpolation methods (such as linear interpolation) cannot accurately fit the details of high-frequency sound waves, resulting in the picket fence effect. When the sampling interval is greater than half a wavelength, periodic imaging artifacts (similar to moiré patterns) appear. Spectral aliasing: high-frequency components are lost, resulting in blurred image edges and insufficient resolution: axial resolution ≥ 1.0 mm, unable to detect tiny defects with a resolution less than 1 mm, such as broken strands of steel core wire. Furthermore, the signal-to-noise ratio is low, and the echo energy of tiny defects is weak, easily drowned out by interpolation noise, resulting in a false negative rate as high as 40%.

[0068] In this embodiment of the invention, the time-domain signal is first converted to the frequency domain by performing a three-dimensional fast Fourier transform on the full matrix data, thus obtaining frequency domain data. The specific process includes: performing a 4096-point three-dimensional fast Fourier transform (FFT) on the full matrix data to map the time-domain signal to the frequency domain, significantly reducing the computational complexity to O(N). 2 TlogN 2(N is the number of array elements, T is the number of time points), laying the foundation for subsequent wavenumber domain parallel computing and improving the real-time performance of the computation. Furthermore, the inference process is implemented using a combination of Xilinx Zynq MPSoC and NVIDIA Jetson GPU: frequency domain parallel processing significantly reduces the computational load, and hardware acceleration further improves the computational speed, reducing the processing time from 18 seconds per frame under the time-domain algorithm to 0.28 seconds. Advantages: It achieves "instant detection and imaging," meeting the needs of rapid field detection, improving detection efficiency by 70% compared to traditional methods, and greatly enhancing the timeliness of detection.

[0069] S230. In the wavenumber domain, the geometric error of the crimp fitting in the frequency domain data is corrected by the arc sphere compensation factor, and the acoustic wave scattering effect at the multi-material interface of the crimp fitting in the frequency domain data is compensated by the phononic crystal bandgap correction term.

[0070] In power transmission lines, crimp fittings commonly involve interfaces between multiple materials, such as steel and aluminum. When sound waves propagate to these interfaces, they undergo several changes: mode conversion (longitudinal wave → transverse wave / surface wave), leading to phase disturbances in the echo signal; and scattering loss (incoherent scattering caused by interface roughness), reducing the signal-to-noise ratio of the defect echo. Existing technologies do not model these effects, directly using single-material acoustic field models (such as free-space Green's function). This results in imaging artifacts, where interface scattering noise is misinterpreted as defect signals, such as the appearance of "false cracks" at steel-aluminum crimp joints, leading to positioning errors. Interface refraction also causes deviations in the calculation of the sound wave propagation path, with the 3D defect positioning error exceeding 3.2%.

[0071] In this embodiment of the invention, in the wavenumber domain, the arc sphere compensation factor C(k) is used. x ,k y This method corrects the geometric errors of the press-fit fittings in the frequency domain data and compensates for the scattering problem of multi-material interfaces in the press-fit fittings by combining the phonon crystal bandgap correction term Δ(ω). By numerically solving the Helmholtz-Kirchhoff integral, precise focusing in the wavenumber domain is achieved, increasing the interface signal-to-noise ratio from 6.2 dB to 38.7 dB and suppressing over 90% of scattering noise.

[0072] Furthermore, the Helmholtz-Kirchhoff integral is an important formula in wave theory, used to describe the propagation and superposition characteristics of sound waves in space. It is the foundation for ultrasonic imaging sound field modeling. The formula is:

[0073] ;

[0074] in, For the sound pressure at the observation point, Let S be the Green's function, describing the sound field distribution of a point source, and S be the surface of the sound source. As a gradient operator, this embodiment of the invention establishes the sound pressure field distribution through the integral model, and combines the superposition of multi-element signals to achieve accurate modeling of the internal sound field of the press-fit fitting.

[0075] The spherical compensation factor is a parameter used in frequency domain and wavenumber domain calculations to correct for the "spherical effect." The spherical effect refers to the phenomenon where the propagation vector of sound waves in the wavenumber domain is constrained by a wavenumber sphere (k...). 2 = This leads to focusing errors in the edge areas.

[0076] ;

[0077] in, The material coupling coefficient is combined with a multi-material interface correction term. Further improve the compensation accuracy to correct geometric errors in wavenumber domain acoustic field migration calculation, ensure imaging resolution in edge regions, and reduce image artifacts.

[0078] Optionally, a phonon crystal bandgap correction term is used to compensate for the acoustic wave scattering effect at the multi-material interface in the press-fit fitting in the frequency domain data, including:

[0079] A phononic crystal bandgap correction term is generated based on the material interface scattering coefficient and acoustic wave propagation delay at the multi-material interface in the crimping fitting; the acoustic wave scattering effect at the multi-material interface in the crimping fitting in the frequency domain data is compensated by the phononic crystal bandgap correction term.

[0080] Specifically, for the acoustic wave scattering correction term introduced at multi-material interfaces (such as steel-aluminum interfaces) in press-fit fittings, a phonon crystal theory-based design is used to compensate for energy loss and phase distortion caused by abnormal acoustic wave scattering at multi-material interfaces. The formula is:

[0081]

[0082] in, The scattering coefficient at the material interface. The propagation delay of sound waves at the interface is determined through experiments or simulations. By generating a phononic crystal bandgap correction term based on the material interface scattering coefficient and sound wave propagation delay at the multi-material interface in the press-fit fitting, the sound wave propagation characteristics at the multi-material interface can be corrected, scattering noise can be suppressed, and the adaptability of the sound field model to complex structures can be improved.

[0083] This invention introduces a phononic crystal bandgap correction term Δ(ω) to model and compensate for acoustic wave scattering at the steel-aluminum interface based on phononic crystal theory. Simultaneously, an arc-shaped probe is used to adapt to the curved surface of the fitting, improving the acoustic coupling efficiency to 90%. Reasoning: The phononic crystal bandgap correction term Δ(ω) effectively compensates for energy loss and phase distortion of the acoustic wave at the interface by fitting the interface scattering coefficient and delay. The arc-shaped probe reduces acoustic energy loss caused by poor fit. Together, these two factors suppress more than 90% of scattering noise. Advantages include: the signal-to-noise ratio at the interface is improved from 6.2dB in traditional methods to 38.7dB; imaging artifacts are significantly reduced; defect location error is reduced to within 0.5mm; and accurate imaging of defects at multi-material interfaces is achieved.

[0084] S240. Perform hybrid interpolation reconstruction on the compensated frequency domain data to generate a three-dimensional acoustic image.

[0085] Specifically, hybrid interpolation reconstruction can employ a hybrid interpolation algorithm, which combines the advantages of different interpolation methods to perform three-dimensional reconstruction of wavenumber domain data. This hybrid interpolation algorithm uses 7th-order sinc kernel interpolation, leveraging the ideal low-pass characteristics of the sinc function in the frequency domain to ensure axial (depth) resolution. Catmull-Rom spline interpolation is used, improving the smoothness of the lateral (planar) data and reducing interpolation noise through local polynomial fitting. Hybrid interpolation reconstruction is then performed on the compensated frequency domain data to generate a three-dimensional acoustic image, balancing axial and lateral resolution and improving the overall clarity and accuracy of the three-dimensional acoustic image.

[0086] Traditional methods suffer from a fence effect error of over 3.2% and are ineffective at detecting minute defects. This invention employs an arc sphere compensation factor. By correcting wavenumber domain calculation errors and combining a hybrid interpolation algorithm that uses a 7th-order sinc kernel in the k_z direction and Catmull-Rom splines in the k_x direction, image artifacts are reduced, and imaging errors are reduced by more than 80%. At the same time, high-resolution imaging with an axial thickness of 0.35 mm and a lateral thickness of 0.75 mm is achieved, which can effectively detect minute defects, and the three-dimensional positioning error is <0.5 mm.

[0087] S250. Defects in the crimping fittings in the three-dimensional acoustic image are identified by a deep learning network model to obtain defect detection results. The defect detection results include a set of parameters that quantitatively describe the defect characteristics. The set of parameters that quantitatively describe the defect characteristics includes scattering amplitude, phase shift, and shape factor. The scattering amplitude is the intensity of the echo at the defect in the crimping fitting. The phase shift is the phase difference between the echo at the defect in the crimping fitting and the echo in the normal area of ​​the crimping fitting. The shape factor is the geometric parameter at the defect in the crimping fitting.

[0088] Specifically, the VTK framework is used to convert the frequency domain processing results into three-dimensional acoustic images, enabling three-dimensional visualization of defects. Simultaneously, a ResNet18 deep learning network is introduced, trained with over 2000 labeled samples to automatically identify defect types (such as broken strands, cracks, and cavities), forming a deep learning network model with an accuracy of ≥92%. This model identifies defects in the press-fit fittings within the three-dimensional acoustic images, yielding defect detection results. These results include a parameter set D={A0,φ,σ} describing the defect characteristics, enabling quantitative evaluation.

[0089] Where A0 is the scattering amplitude, representing the intensity of the echo at the defect in the press-fit fitting, reflecting the defect size and interface characteristics (such as the difference in reflected energy of broken strands or cavities). φ is the phase offset, the phase difference between the echo at the defect and the echo in the normal area of ​​the press-fit fitting, related to the material properties of the defect (such as the acoustic transmission / reflection characteristics of cracks). The shape factor σ is the geometric parameter at the defect in the press-fit fitting, describing the geometric morphology of the defect (such as the spatial distribution characteristics of spherical or crack-like shapes), obtained through three-dimensional image moment calculation. The output defect detection results enable quantitative assessment of defects, assisting inspectors in judging the severity of defects, providing data support for maintenance decisions, and solving the problem of missed detections in traditional methods.

[0090] Existing detection technologies rely on manual analysis, which is inefficient and highly subjective. This invention constructs a deep learning defect classification network based on ResNet18 as the deep learning network model, and trains and optimizes it using a large amount of real-world detection data. This achieves automatic defect identification and classification with an accuracy rate of ≥92%, reducing human interference and improving the objectivity, accuracy, and automation of detection, thus providing a scientific basis for defect handling decisions.

[0091] Figure 5 A flowchart of another phase-array imaging method for press-fit fittings provided in an embodiment of the present invention is shown below. Figure 5 As shown, it includes:

[0092] S1. Acquire ultrasonic echo signals.

[0093] S2, Bandpass filtering + envelope extraction.

[0094] S3, 3D FFT transformation.

[0095] S4, Wavenumber Domain Transfer Calculation.

[0096] S5, Arc Sphere Effect Compensation + Phononic Crystal Bandgap Correction.

[0097] S6, Hybrid Interference Reconstruction.

[0098] S7, 3D Imaging and Intelligent Diagnosis.

[0099] This invention employs 32 array elements for sequential excitation to acquire ultrasonic echo signals. By receiving echoes from the entire 32×32 channel matrix and collecting data for 4096 points, a 32×32×4096 full-matrix dataset is constructed to completely record the internal acoustic field information of the fittings. After bandpass filtering and envelope extraction of the ultrasonic echo signals, a three-dimensional FFT transformation is performed on the entire matrix data at 4096 points, mapping the time-domain signal to the frequency domain. This significantly reduces computational complexity and lays the foundation for subsequent wavenumber domain parallel computation. Wavenumber domain transfer computation introduces an arc spherical compensation factor. To correct wavenumber domain geometric errors, a phonon crystal bandgap correction term Δ(ω) is used to compensate for multi-material interface scattering. Precise wavenumber domain focusing is achieved by numerically solving the Helmholtz-Kirchhoff integral, improving the interface signal-to-noise ratio from 6.2 dB to 38.7 dB and suppressing over 90% of scattering noise. Hybrid interpolation reconstruction is performed at k... z The direction uses 7th-order sinc kernel interpolation, improving the axial resolution to 0.35mm; k x / k y The direction employs Catmull-Rom spline interpolation, achieving a lateral resolution of 0.75mm. This combination effectively suppresses spectral aliasing and improves image clarity. 3D imaging and intelligent diagnosis: The VTK framework is used to convert frequency domain processing results into 3D volumetric data, enabling 3D visualization of defects. Simultaneously, a ResNet18 deep learning network is introduced, trained with over 2000 labeled samples, to automatically identify defect types (such as broken strands, cracks, and cavities) with an accuracy rate ≥92%. A set of defect feature parameters is output for quantitative assessment.

[0100] This invention, through multi-material interface correction and based on phonon crystal theory, establishes a steel-aluminum interface scattering model, derives compensation coefficients and delays, effectively corrects abnormal acoustic wave propagation at the interface, eliminates imaging artifacts, and improves defect location accuracy to within 0.5mm. Real-time breakthrough: Through hardware acceleration and parallel algorithm collaboration, detection and imaging are achieved "instantaneous scanning," meeting the needs of rapid field detection, with detection efficiency improved by 70% compared to traditional methods. Micro-defect detection: The combination of a wideband probe and a high-resolution interpolation algorithm can detect micro-defects such as 0.7mm broken strands, improving the signal-to-noise ratio to over 12dB, solving the problem of missed detections in traditional methods.

[0101] This invention provides a phased-array imaging method for crimp fittings. By acquiring echo signals from an arc-shaped phased-array probe, a three-dimensional acoustic image of the crimp fitting is generated based on the echo signals. Defects in the crimp fitting are then identified within the three-dimensional acoustic image, yielding defect detection results. This method diagnoses defects in crimp fittings, reduces human interference, and improves the objectivity, accuracy, and automation of the detection process. It provides a scientific basis for defect handling decisions, thereby ensuring the safe operation of transmission lines. This invention aims to address the core problems in existing transmission fitting detection technologies, such as multi-material interface imaging distortion, low computational efficiency, and high failure rate of small defects. It provides a high-precision, real-time, and field-adaptable three-dimensional acoustic imaging system for transmission fittings, enabling accurate identification and quantitative assessment of defects such as conductor strand breaks, crimp cavities, and cracks, thus ensuring the safe operation of high-voltage transmission lines.

[0102] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A phased array imaging system for press-fit fittings, characterized in that, The phased array imaging system of the press-fit fitting includes: An arc-shaped phased array probe is used to fit the curved surface structure of the crimping fitting, and to emit ultrasonic signals to the crimping fitting and receive echo signals returned from the crimping fitting. A signal acquisition and processing module is connected to the arc-shaped phased array probe. The signal acquisition and processing module is used to acquire the echo signal acquired by the arc-shaped phased array probe, generate a three-dimensional acoustic image of the crimping hardware based on the echo signal, identify the defects of the crimping hardware in the three-dimensional acoustic image, and obtain the defect detection result. An interactive terminal, connected to the signal acquisition and processing module, is used to display the three-dimensional acoustic image and the defect detection results.

2. The phase-array imaging system for press-fit fittings according to claim 1, characterized in that, The arc-shaped phased array probe comprises 32 arc-shaped phased array elements, and the spacing between adjacent arc-shaped phased array elements is a preset distance.

3. The phase-array imaging system for press-fit fittings according to claim 2, characterized in that, The radius of curvature of the arc-shaped phased array element is 6.9-7.1 mm, the operating frequency band of the arc-shaped phased array element is 1-9 MHz, and the material of the arc-shaped phased array element is lead zirconate titanate piezoelectric ceramic.

4. The phase-array imaging system for press-fit fittings according to claim 2, characterized in that, The preset distance is λ / 2, where λ is the wavelength of the ultrasonic signal emitted by the arc-shaped phased array probe.

5. The phase-array imaging system for press-fit fittings according to claim 1, characterized in that, The signal acquisition and processing module includes: The acquisition unit is connected to the arc-shaped phased array probe, and the acquisition module is used to acquire the echo signal acquired by the arc-shaped phased array probe; The processing unit has its input terminal connected to the acquisition unit and the interactive terminal. The processing unit is used to generate a three-dimensional acoustic image of the crimping fitting based on the echo signal, identify defects in the crimping fitting in the three-dimensional acoustic image, and obtain defect detection results.

6. The phase-array imaging system for press-fit fittings according to claim 1, characterized in that, It also includes a built-in battery; The built-in battery is connected to the arc-shaped phased array probe, the signal acquisition and processing module, and the interactive terminal. The built-in battery is used to power the arc-shaped phased array probe, the signal acquisition and processing module, and the interactive terminal.

7. A phase-array imaging method for press-fit fittings, characterized in that, The phase-array imaging method for the press-fit fittings is applied to the phase-array imaging system for the press-fit fittings according to any one of claims 1-6, wherein the phase-array imaging method for the press-fit fittings includes: The echo signal acquired by the arc-shaped phased array probe is obtained; A three-dimensional acoustic image of the crimping fitting is generated based on the echo signal, and defects in the crimping fitting in the three-dimensional acoustic image are identified to obtain defect detection results.

8. The phase-array imaging method for press-fit fittings according to claim 7, characterized in that, The echo signal acquired by the arc-shaped phased array probe is full-matrix data. Generating a three-dimensional acoustic image of the crimping fitting based on the echo signal includes: Perform a three-dimensional fast Fourier transform on the full matrix data to convert the time-domain signal to the frequency domain, thus obtaining frequency-domain data; In the wavenumber domain, the geometric error of the crimping fitting in the frequency domain data is corrected by an arc sphere compensation factor, and the acoustic wave scattering effect at the multi-material interface in the crimping fitting in the frequency domain data is compensated by a phononic crystal bandgap correction term. The compensated frequency domain data is reconstructed by hybrid interpolation to generate the three-dimensional acoustic image.

9. The phase-array imaging method for press-fit fittings according to claim 8, characterized in that, The method of using a phononic crystal bandgap correction term to compensate for the acoustic wave scattering effect at the multi-material interface in the press-fit fitting in the frequency domain data includes: The phononic crystal bandgap correction term is generated based on the material interface scattering coefficient and acoustic wave propagation delay at the multi-material interface in the press-fit fitting. The acoustic wave scattering effect at the multi-material interface in the press-fit fitting is compensated by the phonon crystal bandgap correction term.

10. The phase-array imaging method for press-fit fittings according to claim 7, characterized in that, Identifying defects in the crimping fitting in the three-dimensional acoustic image to obtain defect detection results includes: The defects of the crimping fitting in the three-dimensional acoustic image are identified by a deep learning network model to obtain the defect detection result; wherein, the defect detection result includes a set of parameters that quantitatively describe the defect characteristics, the set of parameters that quantitatively describe the defect characteristics includes scattering amplitude, phase shift, and shape factor, the scattering amplitude is the intensity of the echo at the defect in the crimping fitting, the phase shift is the phase difference between the echo at the defect in the crimping fitting and the echo in the normal area of ​​the crimping fitting, and the shape factor is the geometric parameter at the defect in the crimping fitting.

Images