Ultrasonic probe calibration method

Abstract

The ultrasonic probe calibration method comprises the following steps: S1, selecting an ultrasonic probe with stable performance from a plurality of ultrasonic probes with the same model, and recording the ultrasonic probe as a standard probe; s2, determining a calibration sample with known acoustic characteristics for a calibration process; s3, measuring the calibration sample by using a standard probe, and storing the measured data as reference data; s4, probes to be calibrated with the same model as the standard probe are used for measuring the calibration samples respectively, and measurement data of the probes to be calibrated are stored; s5, calculating a calibration coefficient of each probe to be calibrated, wherein the calibration coefficient is a ratio of the reference data to the measurement data of the corresponding probe; and S6, applying the calibration coefficient to the subsequent measurement of the corresponding probe so as to correct the measurement result of the probe. According to the method, the calibration process is simplified, the calibration efficiency is greatly improved, the calibration coefficient is calculated through direct comparison, iterative optimization and image processing steps are reduced, calibration of the multiple probes can be rapidly completed, and the method is suitable for a large-scale production scene.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of non-destructive testing, in particular to an ultrasonic probe calibration method. BACKGROUND

[0002] As a non-destructive testing method, ultrasonic testing is widely used in industrial and medical fields. As the core component of transmitting and receiving sound waves, the performance of ultrasonic probe directly determines the accuracy and reliability of the detection results. In practical applications, ultrasonic probes need to select different center frequencies according to the thickness of the material to be detected, the depth and direction of the defect, etc., in order to optimize the detection effect.

[0003] However, the existing ultrasonic probes have the problems of poor consistency and complex calibration, which leads to unstable measurement results. Specifically, 1) the manufacturing differences, wear and tear, and matching problems with the detection system of the probe will all lead to inconsistent measurement results of the same type of probe. 2) The existing calibration methods have obvious defects: for example, Chinese patent CN104620128B relies on multi-array configuration and phantom, which is complex in hardware and has limited environmental applicability; CN105828722B relies on an electromagnetic tracker, which is susceptible to electromagnetic interference and the precision is affected by the distribution of the electromagnetic field; CN109580786B requires high-precision image processing and chromatic aberration calculation, which requires high computing resources and image quality, and the precision decreases when the image conditions are not good. 3) The types of probes, parameters and methods covered by the performance test standards of ultrasonic probes are quite different, resulting in poor consistency of measurement results in different scenarios.

[0004] Therefore, there is an urgent need for an ultrasonic probe calibration method that simplifies the process, improves efficiency, enhances consistency, and reduces environmental dependence. SUMMARY

[0005] To solve the above problems, the present application provides an ultrasonic probe calibration method, which establishes a reference by a standard probe, calculates the calibration coefficient of the same type of probe to correct the measurement results, and the specific technical solution is as follows: An ultrasonic probe calibration method includes the following steps: Step S1: select a performance-stable ultrasonic probe from a plurality of ultrasonic probes of the same type, denoted as a standard probe, and other ultrasonic probes of the same type are denoted as to-be-calibrated probes; Step S2: determine a calibration sample with known acoustic characteristics for the calibration process; Step S3: measure the calibration sample using the standard probe, and save the measured data as reference data; Step S4: measure the calibration sample using the to-be-calibrated probes of the same type as the standard probe, and save the measurement data of each to-be-calibrated probe; Step S5: calculating a calibration coefficient of each to-be-calibrated probe, the calibration coefficient being a ratio of the reference data to the measurement data of the corresponding probe; Step S6: applying the calibration coefficient to subsequent measurement of the corresponding probe to correct the measurement result of the probe.

[0006] Further optimization, in step S1, among multiple ultrasonic probes of the same type, the accuracy of each ultrasonic probe is tested by a standard test block, and the ultrasonic probe with the smallest measurement error is selected as the standard probe.

[0007] Further optimization, in step S2, the known acoustic characteristics of the calibration sample include the sound velocity of the ultrasonic signal in the material, the thickness of the calibration sample, and the depth and size of the internal preset defect.

[0008] Further optimization, in steps S3 and S4, the measurement data includes the amplitude, arrival time, and waveform characteristics of the ultrasonic signal.

[0009] Further optimization, in step S5, the calculation formula of the calibration coefficient is: ; Wherein, K i is the calibration coefficient of the i i th to-be-calibrated probe, D s represents the reference data, and D i is the measurement data of the i i th to-be-calibrated probe.

[0010] Further optimization, the subsequent measurement result of the to-be-calibrated probe is multiplied by the corresponding calibration coefficient to obtain the corrected measurement result, that is: ; Wherein, is the corrected measurement result, M i is the original measurement result of the i i th to-be-calibrated probe, and K i is the calibration coefficient of the i i th to-be-calibrated probe.

[0011] Further optimization, further comprising step S7: periodically repeating steps S3 to S6 on the standard probe and the to-be-calibrated probes to update the calibration coefficient.

[0012] Further optimization, in step S4, when each to-be-calibrated probe measures the calibration sample, it is ensured that the coupling condition between the to-be-calibrated probe and the calibration sample is consistent with the coupling condition of the standard probe in step S3.

[0013] Compared with the prior art, the present application has the beneficial effects: 1. Simplify the calibration process: without complex hardware (such as multi-array, electromagnetic tracker) or high-precision image processing, calibration can be completed only by standard probe and calibration sample, reducing the operation complexity.

[0014] 2. Improve calibration efficiency: by directly comparing and calculating the calibration coefficient, reduce the iteration optimization and image processing steps, can quickly complete the calibration of multiple probes, suitable for large-scale production scenarios.

[0015] 3. Enhance measurement consistency: by correcting the same type of probe with unified calibration coefficient, eliminate the deviation caused by manufacturing differences, wear and other factors, ensure the measurement results of different probes in different scenarios are highly consistent.

[0016] 4. Improve accuracy: reference to the reference data of the standard probe, reduce the dependence on external conditions such as electromagnetic environment and image quality, calibration accuracy is more stable.

[0017] 5. Strong compatibility: suitable for various types and types of ultrasonic probes, suitable for industrial, medical and other multi-field needs; 6. Reduce costs: regular calibration extends the service life of the probe, reduces the repair or replacement costs caused by measurement errors, and reduces the dependence on high-end hardware. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The ultrasonic probe calibration workflow diagram described in the present application; Figure 2 The probe calibration placement diagram; Figure 3 The reference echo data graph, the vertical coordinate is amplitude (unit: mV), the horizontal coordinate is time (unit: μs), and the echo signal characteristics of the standard probe measuring the calibration sample are displayed. DETAILED DESCRIPTION

[0019] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the present application will be described in detail below with reference to the drawings. Obviously, the described embodiments are part of the embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor belong to the scope of protection of the present application.

[0020] This embodiment takes the calibration of a certain type of industrial ultrasonic probe (center frequency 5MHz) as an example to illustrate the implementation process of the present application, as shown in Figure 1

[0021] ​Step S1: Select a standard probe: Among 10 5MHz ultrasonic probes of the same model, use a standard test block to perform an accuracy test: Measure the reflected signal from a flat-bottomed hole with a depth of 20mm on the test block, calculate the error between the measured value of each probe and the actual depth, and select the probe with the smallest error (≤0.1mm) as the standard probe.

[0022] Step S2: Determine the calibration sample: Select a calibration sample with known acoustic properties: the material is 45# steel, the thickness is 50mm, and there are 3 pre-set flat-bottomed holes inside (depths of 10mm, 25mm, and 40mm, and diameter of 2mm respectively), and the sound velocity is known to be 5900m / s.

[0023] Step S3: Obtain reference data: Use standard probe 2 to measure the calibration sample. Apply a coupling agent (such as glycerin) to the surface of calibration sample 1 to ensure good coupling. Figure 2 As shown, the reflected signals from the three flat-bottomed holes were measured respectively, and the signal amplitude (peak value), arrival time (time difference from transmission to reception), and waveform characteristics (such as pulse width) were recorded. Figure 3 As shown, the average of three measurements is taken as the baseline data Ds (e.g., 10mm aperture amplitude 80mV, arrival time 3.4μs; 25mm aperture amplitude 60mV, arrival time 8.5μs; 40mm aperture amplitude 40mV, arrival time 13.6μs).

[0024] Step S4: Obtain measurement data from other probes to be calibrated: Use the remaining 9 probes of the same model to measure the same calibration sample, keeping the coupling conditions consistent with step S3, and record the measurement data Di for each probe. For example: the first probe has an amplitude of 75mV and an arrival time of 3.5μs in a 10mm aperture; an amplitude of 58mV and an arrival time of 8.6μs in a 25mm aperture; and an amplitude of 38mV and an arrival time of 13.8μs in a 40mm aperture.

[0025] Step S5: Calculate the calibration coefficient: according to the formula Calculate the calibration coefficient for each probe. Taking a 10mm aperture as an example, the amplitude calibration coefficient Ki1 for the first probe to be calibrated is approximately 1.07 (80 / 75); the arrival time calibration coefficient Ki2 is approximately 0.97 (3.4 / 3.5). Similarly, calculate the calibration coefficients for the other apertures and take the average value as the final calibration coefficient for the probe.

[0026] Step S6: Apply calibration coefficient: In actual testing, when the first probe measures a defect in a workpiece, the original amplitude is 90mV, and the corrected amplitude is 90×1.07≈96.3m; the original arrival time is 5.2μs, and the corrected time is 5.2×0.97≈5.04μs, ensuring that the result is consistent with the standard probe measurement.

[0027] Step S7: Periodic calibration: Repeat steps S3 to S6 every 3 months to update the calibration coefficients of each probe to adapt to the degradation of probe performance.

[0028] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for calibrating an ultrasonic probe, characterized in that, Includes the following steps: Step S1: Select a stable ultrasonic probe from multiple ultrasonic probes of the same model and designate it as the standard probe. The other multiple ultrasonic probes of the same model are designated as probes to be calibrated. Step S2: Select a calibration sample with known acoustic properties for the calibration process; Step S3: Use a standard probe to measure and calibrate the sample, and save the measured data as reference data; Step S4: Use the same model of probe to be calibrated as the standard probe to measure the calibration sample respectively, and save the measurement data of each probe to be calibrated; Step S5: Calculate the calibration coefficient for each probe to be calibrated, where the calibration coefficient is the ratio of the reference data to the measurement data of the corresponding probe; Step S6: Apply the calibration coefficient to subsequent measurements of the corresponding probe to correct the measurement results of that probe.

2. The ultrasonic probe calibration method according to claim 1, characterized in that, In step S1, among multiple ultrasonic probes of the same model, the accuracy of each ultrasonic probe is tested using a standard test block, and the ultrasonic probe with the smallest measurement error is selected as the standard probe.

3. The ultrasonic probe calibration method according to claim 2, characterized in that, In step S2, the known acoustic properties of the calibration sample include the speed at which the ultrasonic signal propagates in the material, the thickness of the calibration sample, and the depth and size of the internal pre-set defects.

4. The ultrasonic probe calibration method according to claim 3, characterized in that, In steps S3 and S4, the measurement data includes the amplitude, arrival time, and waveform characteristics of the ultrasonic signal.

5. The ultrasonic probe calibration method according to claim 4, characterized in that, In step S5, the formula for calculating the calibration coefficient is: ； Among them, K i For the first i The calibration coefficient of each probe to be calibrated, D s D represents the baseline data. i For the first i Measurement data of the probe to be calibrated.

6. The ultrasonic probe calibration method according to claim 5, characterized in that, In step S6, the subsequent measurement results of the probe to be calibrated are multiplied by its corresponding calibration coefficient to obtain the corrected measurement results, i.e.: ； in, For the corrected measurement results, M i For the first i The original measurement results of the probe to be calibrated, K i For the first i The calibration coefficient of each probe to be calibrated.

7. The ultrasonic probe calibration method according to claim 6, characterized in that, It also includes step S7: periodically repeating steps S3 to S6 for the standard probe and the probe to be calibrated to update the calibration coefficients.

8. The ultrasonic probe calibration method according to claim 7, characterized in that, In step S4, when measuring the calibration sample with each probe to be calibrated, ensure that the coupling conditions between the probe and the calibration sample are consistent with the coupling conditions of the standard probe described in step S3.

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