Time correction gain method, module for phased array ultrasound device, and ultrasound device
By constructing a dynamic time-corrected gain function in a phased array ultrasound device and fitting the attenuation function using Hilbert transform and C1-type exponential model, the echo artifact problem caused by linear gain mode is solved, thereby improving imaging quality and detection accuracy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TAIYUAN UNIVERSITY OF SCIENCE AND TECHNOLOGY
- Filing Date
- 2026-04-13
- Publication Date
- 2026-07-10
AI Technical Summary
In existing phased array ultrasonic testing technology, the echo artifact problem caused by linear gain mode has not been effectively solved, and there is a lack of systematic research on improving imaging quality.
An ultrasonic propagation model was created in a multiphysics simulation software. The attenuation function was fitted using Hilbert transform and C1-type exponential model, and a dynamic time-corrected gain function was constructed to adaptively compensate for the ultrasonic echo. The signal was then processed using a phased array time-corrected gain module.
It significantly alleviates the imaging drift problem caused by abrupt changes in the gain amplitude of traditional segmented TCG, improves the accuracy of defect identification and quantitative detection, suppresses detection artifacts, and achieves higher quality imaging results.
Smart Images
Figure CN122361632A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of ultrasonic signal processing, and in particular to a time correction gain method for phased array ultrasonic equipment, as well as a corresponding time correction gain module and phased array ultrasonic equipment. Background Technology
[0002] Ultrasonic nondestructive testing is a testing method that utilizes the propagation characteristics (such as reflection and scattering) of ultrasonic waves in the substrate material being tested to collect echo signals, and then processes the echo signals to generate result signals or images. Phased array ultrasound, based on traditional ultrasound, adjusts the transducer, replacing the single piezoelectric crystals with an array arrangement. After applying a time delay law, sound waves can be focused at different positions and depths, resulting in a very wide range of applications.
[0003] Due to the inherent characteristics of ultrasound, it scatters to varying degrees in polycrystalline materials (mostly metallic materials), macroscopically manifesting as attenuation. To reduce the impact of attenuation on detection results, time-corrected gain (TCG) of phased arrays has been a widely used and efficient method. TCG is an important gain method for ultrasound echoes; it uses a built-in TCG function to amplify the ultrasound echo based on the attenuation amplitude at different sound paths. However, current phased array ultrasound detection technologies often focus on improving the physical shape of the probe itself to suit diverse detection needs, with little research on how to improve the imaging quality of ultrasound echoes, lacking a systematic approach. Existing TCG gains are mostly piecewise functions, employing different linear gains in different time domain intervals. This linear gain method is prone to artifacts after gaining due to the linear amplitude variation. Summary of the Invention
[0004] To address the issue of poor path compensation performance and artifacts in phased array ultrasound devices based on linear gain TCG modules, this invention provides a novel time-correction gain method for phased array ultrasound devices, along with a corresponding time-correction gain module and phased array ultrasound device.
[0005] The technical solution provided by this invention is as follows: A time correction gain method for a phased array ultrasonic device includes the following steps: S1: Create a two-dimensional ultrasonic propagation model of the sound field of the probe object of the specified material in a multiphysics simulation software, and conduct simulation tests at each defect depth h using a specified type of ultrasonic probe; thereby obtaining the first binary sequence {V, t} composed of time t and voltage amplitude V. After preprocessing the first binary sequence, the corresponding original echo signal V(t) is obtained.
[0006] S2: Construct an analytic signal Z(t) by performing a Hilbert transform on V(t) at any defect depth; generate the envelope of Z(t) and use it as the A-scan signal at the current defect depth h, then extract its peak value A. max A second binary sequence {Amax, h} is generated based on the peak values of the A-scan signals at different defect depths.
[0007] S3: Calculate the attenuation rate Dr of the peak value at any defect depth relative to the peak value at the reference depth h0, and then generate a third binary sequence {Dr, h}. Determine the mapping relationship between time t and defect depth h based on the signal propagation law of the simulated ultrasonic probe in the specified material, and convert the third binary sequence into a fourth binary sequence {Dr, t}.
[0008] S4: Adopt the following C 1 The exponential model is fitted to the fourth binary sequence to obtain the decay function Dr(t) for the current material and probe type: .
[0009] In the above formula, A , k , u These are the three attenuation coefficients to be determined in the attenuation function.
[0010] S5: Select the reciprocal function of the attenuation function corresponding to the material and probe type as the time correction gain function to dynamically compensate the output signal Vout(t) of the phased array ultrasound equipment.
[0011] As a further improvement of the present invention, the preprocessing process includes data resampling of the first binary sequence based on the probe's main frequency Fc and bandpass filtering.
[0012] The probe's main frequency Fc and the resampling sampling frequency Fs satisfy the following equation: .
[0013] As a further improvement of the present invention, the constructed analytical signal The expression is as follows: ; In the above formula, Indicates the Hilbert transform operation; Original signal The signal obtained after Hilbert transform; j It represents a complex unit.
[0014] As a further improvement to this invention, the expression for the Hilbert transform operation is: ; In the above formula, " " indicates Cauchy's principal value; Indicates a unit of time.
[0015] As a further improvement of the present invention, the formula for calculating the attenuation rate Dr(h) of the peak value Amax(h) of the A-scan signal at any defect depth h is as follows: ; In the above formula, This represents the peak value of the A-scan signal at the reference depth h0.
[0016] As a further improvement of the present invention, in the ultrasonic probe, the mapping relationship between time t and defect depth h is related to the type of ultrasonic probe; based on the simulation test data of each type of ultrasonic probe, a dedicated attenuation function Dr(t) is created for each type of ultrasonic probe under a specified material.
[0017] As a further improvement to this invention, the material of the probe in the ultrasonic propagation model is changed, and a unique attenuation function is created for any type of ultrasonic probe in the detection scenario corresponding to each material of the probe.
[0018] As a further improvement of the present invention, the expression for the compensated output signal Vout(t) is as follows: ; In the above formula, , and Representing the detection materials and probe type The three attenuation coefficients in the corresponding attenuation function; A0 represents the amplitude enhancement coefficient determined based on the amplitude of the original echo signal V(t) output by the current probe.
[0019] The present invention also includes a phased array time correction gain module, which stores time correction gain functions corresponding to arbitrary probe materials and probe types, pre-generated using the time correction gain method of the phased array ultrasonic equipment as described above. It is used to dynamically compensate the received echo signal by selecting the corresponding time correction gain function based on the known probe type and the material type of the probe object during any detection mission of the phased array ultrasonic equipment.
[0020] The present invention also includes a phased array ultrasonic device, which employs the phased array time correction gain module as described above.
[0021] The present invention has the following beneficial effects: This invention first uses multiphysics simulation software to design different types of ultrasonic probes to simulate detection on objects of various materials and defect depths, and then analyzes the propagation characteristics of the two-dimensional sound field of the phased array ultrasonic probe in different targets based on the obtained simulation data; thus laying the data foundation for creating a higher quality time-corrected gain function.
[0022] In the analysis of the probe's attenuation characteristics, this paper first proposes to use C... 1 The attenuation function is fitted by an exponential function. This nonlinear function of a continuously differentiable function can more effectively fit the attenuation curve of the actual ultrasonic wave in the material, realize smooth gain compensation of the echo amplitude in the time domain, significantly alleviate the imaging drift problem caused by the sudden change of gain amplitude in traditional segmented TCG, suppress detection artifacts, and improve the accuracy of defect identification and quantitative detection.
[0023] This invention utilizes multiphysics simulation to model all typical detection objects and application scenarios in real-world applications. It also allows for the construction of data processing modules applicable to devices with time-corrected gain functions in different scenarios, enabling flexible deployment. Furthermore, it allows for application without requiring technological modifications to existing probes, demonstrating strong feasibility for industrial-scale deployment. Attached Figure Description
[0024] Figure 1 This is a flowchart of the time correction gain method for the phased array ultrasonic device provided in Embodiment 1 of the present invention.
[0025] Figure 2 This is the ultrasonic propagation model created during the simulation process in Embodiment 1 of the present invention.
[0026] Figure 3 This is a comparison chart of analytical signals obtained at different defect depths.
[0027] Figure 4 Simulation images of perforated models at different depths constructed for the simulation testing phase; the defect depths of parts (a), (b), and (c) in the figure are 5 mm, 10 mm, and 20 mm, respectively.
[0028] Figure 5 The amplitude-frequency response curve of the FIR bandpass filter designed for the simulation and testing phase. Detailed Implementation
[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.
[0031] Example 1 This embodiment provides a time-correction gain method for phased array ultrasonic equipment. This method uses multiphysics simulation software to simulate the sound field propagation process of probes from different types of phased array ultrasonic equipment in various materials, and collects ultrasonic echo data from the probe under different defect conditions. Then, bandpass filtering and Hilbert transform are performed on the data to obtain envelope information for different types of defects. The attenuation function of ultrasonic waves in the material is then fitted using the amplitude of echo signals from defects at different depths (sound paths). This allows for the construction of a time-correction gain function that can adaptively compensate for defect signals with different sound paths, thereby achieving precise gain adjustment of the ultrasonic echo signal output by the equipment.
[0032] Specifically, such as Figure 1 As shown, the time correction gain method for the phased array ultrasonic device provided in this embodiment includes the following steps: S1: Create a two-dimensional ultrasonic propagation model of the sound field of the probe object of the specified material in a multiphysics simulation software, and conduct simulation tests at each defect depth h using a specified type of ultrasonic probe; thereby obtaining the first binary sequence {V, t} composed of time t and voltage amplitude V. After preprocessing the first binary sequence, the corresponding original echo signal V(t) is obtained.
[0033] In practical applications, the propagation of the two-dimensional sound field emitted by a phased array ultrasonic probe within the target material is affected by both the material type and the probe type. The material type influences the attenuation rate of the ultrasonic wave, while the probe type primarily affects the excitation frequency of the ultrasonic wave, the focusing of the ultrasonic beam within the material, and the propagation path of the ultrasonic wave. In this embodiment, the material selected for the detection target can include various metal materials commonly used in engineering fields, such as stainless steel, chromium-molybdenum heat-resistant steel, and low-alloy steel. The probe types mainly include direct-down and angled-down probes.
[0034] The simulation process of two-dimensional sound field propagation in this embodiment was completed in COMSOL Multiphysics simulation software. Taking a direct-type probe as an example, the created ultrasonic propagation model is as follows: Figure 2As shown in the model, the ultrasonic probe is divided into three parts from top to bottom, with the top being a backing damping layer. Below the backing layer is the transducer, which consists of multiple independent piezoelectric crystals arranged to achieve bidirectional acoustic-to-electrical conversion. Below the transducer is a wedge, positioned outside the matching layer and in direct contact with the workpiece. In this embodiment, an absorption layer is also placed below the workpiece to absorb sound waves propagating to the bottom of the workpiece, preventing reflections that could interfere with defect echoes.
[0035] Furthermore, to accurately capture the propagation process of sound waves within the target material, this embodiment also incorporates a series of deep-hole models at different depths within the workpiece as artificially simulated defects, to receive echo signals from defects at varying depths. These deep holes help assess the reflection and attenuation of ultrasonic waves when they encounter defects at different depths (sound path).
[0036] Finally, in this embodiment, an experimental simulation was conducted using multiphysics simulation software within the constructed ultrasonic propagation model to collect the ultrasonic echo data generated by the simulation model. The model output data consists of a time series and echo voltage generated according to a preset sampling frequency. Next, this embodiment analyzes the acquired sequence data based on the sampling frequency of the two indicators, aligns the two data points along the time axis, and thus obtains a first binary sequence {V, t} composed of a series of binary data (V, t).
[0037] In practical applications, to ensure signal quality, this embodiment also requires preprocessing of the acquired first binary sequence. The preprocessing includes data resampling based on the probe's main frequency Fc and bandpass filtering. Specifically, when the sampling frequency of the (V, t) data of the binary sequence after time-axis alignment is too high or too low, data resampling is necessary to meet the input sampling frequency required for subsequent bandpass filtering. For example, in practical applications, the probe's main frequency Fc and the resampling sampling frequency Fs satisfy the following equation: .
[0038] This embodiment uses MATLAB software to construct an FIR-based bandpass filter that can simultaneously filter low-frequency and high-frequency noise, DC bias, and prevent spectral aliasing distortion. The implementation principle of this bandpass filter is as follows: ; In the above formula, The signal containing the original defect voltage received by the probe is the input signal of the filter. This represents the time-domain impulse response of the bandpass filter; This is the output signal after filtering by the bandpass filter; Indicates a unit of time.
[0039] The passband and bandwidth parameters of the bandpass filter need to be flexibly set according to the center frequency (ultrasound excitation frequency) of the simulated ultrasound probe. For example, in this embodiment, the center frequency of the simulated ultrasound probe is set to 5MHz, the passband of the bandpass filter is set to 3-7MHz, and the bandwidth is 4MHz, which can effectively filter low-frequency and high-frequency noise.
[0040] Finally, the data points in the preprocessed first binary sequence constitute the original echo signal acquired during the simulation, which is denoted as V(t) in this embodiment. In subsequent schemes, the defect depth h in the detection target, as well as the probe type α and material type β, can be adjusted in the multiphysics simulation software to obtain other related original echo signals.
[0041] S2: Construct an analytic signal Z(t) by performing a Hilbert Transform (HT) on V(t) at any defect depth; generate the envelope of Z(t) and use it as the A-scan signal at the current defect depth h, then extract its peak value A. max A second binary sequence {Amax, h} is generated based on the peak values of the A-scan signals at different defect depths.
[0042] The Hilbert transform is a core tool in signal processing, belonging to the LTI (Low-Intensity Transform) system. It is widely used in ultrasonic nondestructive testing (NDT) and phased array ultrasonic testing (PAUT) for envelope extraction and precise defect localization. In the high-frequency oscillating signal obtained after bandpass filtering, its envelope reflects the core characteristics of the defect. The main purpose of the Hilbert transform is to construct an analytic signal, expanding the real signal constructed using simulation data into a complex signal. In this embodiment, the Hilbert transform is first performed on V(t) at any defect depth, and then the signals before and after the transform are used to synthesize the required complex analytic signal Z(t). Specifically, the constructed analytic signal... The expression is as follows: ; In the above formula, Original signal The signal obtained after Hilbert transform; j Indicates the complex unit; The Hilbert transform operation is expressed as follows: ; In the above formula, " "Indicates Cauchy principal value.
[0043] Next, the envelope of the analytical signal is extracted, which is the characteristic signal of the deep hole defect. This characteristic signal is displayed on the image as a voltage signal in the time domain, i.e., the A-scan signal of the ultrasonic spectrum. For example, Figure 3The figure shows the waveforms of the analytical signals obtained from 316H stainless steel under simulated testing conditions, including those without holes and those containing 5 mm, 10 mm, and 20 mm deep holes. The red amplitude trajectory around the outer edge of the waveform in the figure represents the envelope of the analytical signal.
[0044] In this embodiment, the peak value Amax of the envelope (A-scan signal) of each analytical signal is extracted, and Amax and its corresponding defect depth h are taken as a data point (Amax, h). Based on this, the same processing is performed on the A-scan signals at different defect depths to obtain a second binary sequence {Amax, h} consisting of a series of data points.
[0045] S3: Calculate the attenuation rate Dr of the peak value at any defect depth relative to the peak value at the reference depth h0, and then generate a third binary sequence {Dr, h}. Determine the mapping relationship between time t and defect depth h based on the signal propagation law of the simulated ultrasonic probe in the specified material, and convert the third binary sequence into a fourth binary sequence {Dr, t}.
[0046] In the second binary sequence obtained in the previous step, as the defect depth increases, the peak value of the A-scan signal corresponding to each defect depth also decreases continuously. To analyze the decrease ratio of Amax under different defect depth conditions, this embodiment introduces an attenuation rate index. The formula for calculating the attenuation rate Dr(h) of the peak value Amax(h) of the A-scan signal at any defect depth h is: ; In the above formula, This represents the peak value of the A-scan signal at the reference depth h0.
[0047] Based on the calculated decay rate Dr corresponding to each peak Amax, this embodiment can further obtain the third binary sequence {Dr, h}.
[0048] As previously mentioned, the propagation of a two-dimensional sound field in a detection target is related to the probe type and material type. Therefore, under the same material type and probe type, there is a certain mapping relationship between the propagation time of the ultrasonic signal and the depth range it reaches. This embodiment can determine the mapping relationship between time t and defect depth h based on the signal propagation law of a simulated ultrasonic probe in a specified material (in practical applications, it can be determined based on the peak time of the original echo signal V(T) at different defect depths), i.e., "h→t". On this basis, since the third binary sequence has essentially established a mapping relationship between attenuation rate and defect depth, i.e., "Dr→h", this embodiment can further obtain the mapping relationship between attenuation rate and time, and thus obtain the fourth binary sequence {Dr, t}.
[0049] S4: Adopt the following C 1 The exponential model is fitted to the fourth binary sequence to obtain the decay function Dr(t) for the current material and probe type: .
[0050] In the above formula, A , k , u These are the three attenuation coefficients to be determined in the attenuation function.
[0051] To more accurately reflect the attenuation effect of ultrasonic signals in the target material, this embodiment uses a C-meter containing three core parameters. 1 An exponential model is used to fit the signal. This function model is a continuously differentiable function, meaning its first derivative exists and is continuous. In this embodiment, this smooth and continuous time-domain function is used to describe the attenuation of the ultrasound signal. By adaptively compensating for the signal gain, artifacts and other problems caused by linear gain can be effectively reduced.
[0052] It is important to emphasize that the mapping relationship between time t and defect depth h in ultrasonic probes is related to the type of ultrasonic probe. Based on the simulation test data of each type of ultrasonic probe, a unique attenuation function Dr(t) is created for each type of ultrasonic probe under a specified material. Furthermore, by changing the material of the probe object in the ultrasonic propagation model and repeating the aforementioned simulation test and data processing steps, a unique attenuation function can be created for any type of ultrasonic probe in the detection scenario corresponding to each material probe object.
[0053] That is, the embodiment can conduct repeated simulation experiments by adjusting experimental parameters, and then analyze the experimental data to obtain the attenuation function of ultrasonic signal transmission when any ultrasonic probe is used for detection in any type of material. In this embodiment, it is denoted as . The subscripts α and β represent the detection material and probe type corresponding to the function.
[0054] S5: Select the reciprocal function of the attenuation function corresponding to the material and probe type as the time-corrected gain function (TCG function) to dynamically compensate the output signal Vout(t) of the phased array ultrasound device. In this embodiment, the expression of the compensated output signal Vout(t) is as follows: ; In the above formula, , and Representing the detection materials α and probe type βThe three attenuation coefficients in the corresponding attenuation function; A0 represents the amplitude enhancement coefficient determined based on the amplitude of the original echo signal V(t) output by the current probe.
[0055] Figure 3 The envelope amplitude of the original echo signal gradually decreases with increasing defect depth. However, in this embodiment, after amplitude enhancement and adaptive gain are applied to the original signal from the probe, the echo amplitudes of the signals from defects at different depths can be made to reach similar levels. Furthermore, after amplitude enhancement, the corresponding voltage readings are also increased to the volt (V) level. Of course, in this embodiment, the amplitude enhancement coefficient A0 can be flexibly adjusted according to the amplitude of the echo signal to ensure the readability of the output signal. For example, when the output signal of a device is in the range of 10-50mV, the value of A0 can be set to 100, thereby amplifying the output signal to the range of 1-5V.
[0056] Example 2 Based on the scheme in Embodiment 1, this embodiment further provides a phased array time correction gain module, which stores TCG functions corresponding to arbitrary probe materials and probe types pre-generated using the time correction gain method of the phased array ultrasonic equipment as described in Embodiment 1. It is used to dynamically compensate the received echo signal in any detection mission of the phased array ultrasonic equipment by selecting the corresponding time correction gain function according to the known probe type and the material type of the probe object.
[0057] This phased array time correction gain module is essentially a computer device, comprising a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it selects the corresponding time correction gain function based on the known probe type and the material type of the object being probed, and dynamically compensates the received echo signal before outputting it.
[0058] In practical applications, the computer device can be installed as an embedded module in a phased array ultrasonic device, or it can be a standalone computer device, such as a laptop, tablet, desktop computer, or a rack server, blade server, tower server, or cabinet server (including standalone servers or server clusters composed of multiple servers) capable of executing computer programs.
[0059] The computer device in this embodiment includes, but is not limited to, a memory and a processor that can be interconnected via a system bus. In this embodiment, the memory (i.e., the readable storage medium) includes flash memory, hard disk, multimedia card, card-type memory (e.g., SD or DX memory), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memory, magnetic disk, optical disk, etc. In some embodiments, the memory can be an internal storage unit of the computer device, such as the hard disk or RAM of the computer device. In other embodiments, the memory can also be an external storage device of the computer device, such as a plug-in hard disk, smart media card (SMC), secure digital card (SD), flash card, etc. Of course, the memory can also include both internal storage units and external storage devices of the computer device. In this embodiment, the memory is typically used to store the operating system and various application software installed on the computer device. Furthermore, the memory can also be used to temporarily store various types of data that have been output or will be output.
[0060] In some embodiments, the processor may be a central processing unit (CPU), a controller, a microcontroller, a microprocessor, or other data processing chip. The processor is typically used to control the overall operation of a computer device.
[0061] In practical applications, this embodiment also provides a phased array ultrasonic device, which employs the phased array time correction gain module as described above.
[0062] Simulation test To further verify the performance of the time correction gain method for the phased array ultrasonic device provided by this invention, technicians simulated and tested the relevant circuit scheme; the experimental process is as follows: I. Simulation Experiment This experiment constructed an ultrasonic propagation model for a direct-down probe using COMSOL Multiphysics software. Four target materials were used: 20# steel, 20G boiler-grade steel, 316H stainless steel, and 12Cr1MoVG chromium-molybdenum heat-resistant steel. Four basic models were constructed for each material: a no-hole model, a 5 mm deep-hole model, a 10 mm deep-hole model, and a 20 mm deep-hole model, for ultrasonic testing simulation experiments. The no-hole model served as a control group. The models with holes were as follows: Figure 4 As shown, this model serves as the experimental group. This experiment uses the above model to investigate the echo signal amplitude and ultrasonic attenuation at different sound paths of ultrasound.
[0063] The data obtained from the simulation experiment was exported and preprocessed. The sampling frequency (Fs) of the acquired data was determined based on the center frequency (Fc) of the phased array ultrasonic probe. The acquired data was then resampled to ensure it met processing requirements. A bandpass filter based on FIR was constructed using MATLAB software to bandpass filter the resampled data, removing high / low frequency noise and DC bias from the ultrasonic echo signal, preventing spectral aliasing, and obtaining the bandpass-filtered data. The amplitude-frequency response curve of the FIR bandpass filter used in this experiment is shown below. Figure 5 As shown. Then, a Hilbert transform is performed on the bandpass filtered data to obtain a high-frequency oscillation signal, and the envelope of the high-frequency oscillation signal is extracted. Next, the echo envelope data of defects at different depths in the same material are arranged sequentially by depth, and the echo amplitude attenuation information is analyzed. The attenuation is then assessed using a C0 method. 1 The exponential model is used for nonlinear fitting to obtain the attenuation function of the echo amplitude of ultrasound in the material, and finally the desired time-corrected gain (TCG) function is obtained.
[0064] II. Performance Testing 2.1 Normalized Correlation Coefficient (NCC) This experiment first used the normalized correlation coefficient to analyze the C-values constructed from simulation data of different models. 1 The TCG function is used to assess whether the waveform consistency of the device's output signal remains good after waveform gain. The smaller the distortion caused by the gain, the closer the NCC value is to 100%. The experimental results are shown in Table 1 below: Table 1: NCC Level (%) for Each Model Defect depth (mm) 316H 20# 20G 12Cr1MoVG 5 90.34 87.30 97.34 99.81 10 88.67 90.12 96.95 89.78 20 87.73 87.87 96.74 99.09 Analysis of the data in the table above shows that the time-corrected gain function models provided by this invention exhibit good waveform consistency. The NCC values for 20G steel at different depths are 97.34%, 96.95%, and 96.74%, respectively, indicating that the waveforms before and after gain are almost undistorted, effectively representing the location and depth information contained in the defect signal. The NCC values for 12Cr1MoVG alloy steel at different depths are 99.81%, 89.78%, and 99.09%, respectively, indicating that the fine-grained steel has a very small impact on ultrasonic scattering, and therefore the effect on waveform distortion is also weak, which can be considered as only a slight filtering and gain effect.
[0065] 2.2 Using Normalized Mean Squared Error (NMSE) This experiment further uses normalized mean square error (NMSE) to evaluate the similarity of the waveforms before and after the gain. NMSE is an error index that eliminates the effects of amplitude, unit error, and DC offset. The more similar the waveforms are before and after the gain, the smaller the NMSE value. The experimental results are shown in Table 2 below: Table 2: NMSE levels of each model Defect depth (mm) 316H 20# 20G 12Cr1MoVG 5 0.21327 0.25409 0.05313 0.00384 10 0.25652 0.19755 0.06094 0.11436 20 0.23547 0.24261 0.06522 0.01822 Analysis of the data in the table above shows that the signal gain of the TCG function provided by this invention has good anti-artifact performance. The NMSE exponents for 20G steel are 0.05313, 0.06094, and 0.06522, respectively, while those for 12Cr1MoVG alloy steel are 0.00384, 0.11436, and 0.01822, respectively. Only the value for the 10 mm deep hole in the 12Cr1MoVG model is relatively high, which, considering the effects of filtering and gain, indicates that the TCG gain method has a very small impact on the echo amplitude and DC offset.
[0066] The above-described embodiments are merely one implementation of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.
Claims
1. A time correction gain method for a phased array ultrasonic device, characterized in that, It includes: A two-dimensional ultrasonic propagation model of the sound field of the probe object of a specified material is created in a multiphysics simulation software; simulation test is performed at each defect depth h using a specified type of ultrasonic probe to obtain the first binary sequence {V, t} consisting of time t and voltage amplitude V; after preprocessing, the corresponding original echo signal V(t) is obtained. After performing a Hilbert transform on V(t) at any defect depth, an analytic signal Z(t) is constructed; the envelope of Z(t) is generated and used as the A-scan signal at the current defect depth h, and its peak value A is extracted. max A second binary sequence {Amax, h} is generated based on the peak values of the A-scan signals at different defect depths. Calculate the attenuation rate Dr of the peak value at any defect depth relative to the peak value at the reference depth h0, and then generate a third binary sequence {Dr, h}; determine the mapping relationship between time t and defect depth h according to the signal propagation law of the simulated ultrasonic probe in the specified material, and convert the third binary sequence into a fourth binary sequence {Dr, t}. Adopting, such as C 1 The exponential model is fitted to the fourth binary sequence to obtain the decay function Dr(t) for the current material and probe type: ； In the above formula, A , k , u These are the three attenuation coefficients to be determined in the attenuation function; The reciprocal function of the attenuation function corresponding to the material and probe type is selected as the time correction gain function to dynamically compensate the output signal Vout(t) of the phased array ultrasound device.
2. The time correction gain method for phased array ultrasonic equipment according to claim 1, characterized in that: The preprocessing process includes data resampling of the first binary sequence based on the probe's main frequency Fc and bandpass filtering. The probe's main frequency Fc and the resampling sampling frequency Fs satisfy the following equation: 。 3. The time correction gain method for phased array ultrasonic equipment according to claim 1, characterized in that: Constructed analytic signal The expression is as follows: ； In the above formula, Indicates the Hilbert transform operation; Original signal The signal obtained after Hilbert transform; j It represents a complex unit.
4. The time correction gain method for a phased array ultrasonic device according to claim 3, characterized in that: The expression for the Hilbert transform operation is: ； In the above formula, " "Indicates Cauchy principal value; Indicates a unit of time.
5. The time correction gain method for a phased array ultrasonic device according to claim 1, characterized in that: The formula for calculating the attenuation rate Dr(h) of the peak value Amax(h) of the A-scan signal at any defect depth h is: ； In the above formula, This represents the peak value of the A-scan signal at the reference depth h0.
6. The time correction gain method for a phased array ultrasonic device according to claim 1, characterized in that: In the ultrasonic probe, the mapping relationship between time t and defect depth h is related to the type of ultrasonic probe; Based on simulation test data for each type of ultrasonic probe, a unique attenuation function Dr(t) is created for each type of ultrasonic probe under specified materials.
7. The time correction gain method for a phased array ultrasonic device according to claim 6, characterized in that: The material of the probe object in the ultrasonic propagation model is changed, and a unique attenuation function is created for the probe object of any type of ultrasonic probe in the detection scenario corresponding to each material.
8. The time correction gain method for a phased array ultrasonic device according to claim 7, characterized in that: The expression for the compensated output signal Vout(t) is as follows: ； In the above formula, , and They represent the detection materials. and probe type The three attenuation coefficients in the corresponding attenuation function; A0 represents the amplitude enhancement coefficient determined based on the amplitude of the original echo signal V(t) output by the current probe.
9. A phased array time correction gain module, characterized in that: It stores time correction gain functions corresponding to any probe material and probe type, pre-generated using the time correction gain method of the phased array ultrasonic device as described in any one of claims 1-8; It is used to dynamically compensate for the received echo signal by selecting the corresponding time correction gain function based on the known probe type and the material type of the object being detected in any detection mission of a phased array ultrasonic device.
10. A phased array ultrasonic device, characterized in that: It employs the phased array time correction gain module as described in claim 9.