Internal detection method and device for service closed metal structure and electronic equipment

Abstract

The invention provides an in-service closed metal structure internal detection method and device and electronic equipment, and relates to the technical field of ultrasonic detection. The method comprises the following steps: acquiring geometric parameters of a metal structure; wherein the geometric parameters comprise the wall thickness and the outer diameter of the metal structure; controlling the high-frequency ultrasonic probe to emit high-frequency ultrasonic waves and receive first echoes; determining echo time according to the geometric parameters, and judging whether the working condition inside the metal structure is liquid or not according to the echo time and the first echo amplitude; when the working condition in the metal structure is non-liquid, the first low-frequency ultrasonic probe is controlled to emit, and the second low-frequency ultrasonic probe is controlled to receive a second echo; determining the internal working condition of the metal structure according to the second echo and the discrimination line of each working condition; wherein the working conditions comprise air, ice and concrete. The internal working condition of the closed metal structure can be rapidly detected.

Description

Technical Field

[0001] The present invention relates to the field of ultrasonic detection technology, and in particular to a method, a device and an electronic device for detecting the interior of a closed metal structure in service. Background Art

[0002] Existing methods for internal state detection are mainly aimed at internal defect detection, such as conventional X-ray methods and infrared thermal imaging methods. X-ray detection poses certain safety risks to operators due to its radiation. Long-term exposure to high doses of X-ray radiation may cause health problems such as skin damage and cancer. In addition, the equipment required for X-ray detection is expensive, the detection speed is relatively slow, and the efficiency is low. It takes several hours from the start of transillumination to the evaluation of the results. Infrared thermal imaging achieves imaging by detecting temperature differences on the surface of an object. It is suitable for detecting temperature changes caused by internal defects, thereby discovering problems inside the object, but cannot identify internal conditions.

[0003] Since the X-ray method has a slow detection speed and the infrared thermal imaging method cannot identify the internal conditions of a closed structure, there is an urgent need for a method that can quickly detect the internal conditions of a closed metal structure. Summary of the invention

[0004] The embodiments of the present invention provide a method, a device and an electronic device for detecting the interior of a closed metal structure in service, so as to solve the problem of slow speed of detecting the interior of the closed metal structure.

[0005] In a first aspect, an embodiment of the present invention provides a method for detecting the interior of a closed metal structure in service, comprising:

[0006] Acquire geometric parameters of the metal structure; wherein the geometric parameters include the wall thickness and outer diameter of the metal structure;

[0007] Control the high-frequency ultrasonic probe to transmit high-frequency ultrasonic waves and receive the first echo;

[0008] Determine the echo time according to the geometric parameters, and judge whether the internal working condition of the metal structure is liquid according to the echo time and the amplitude of the first echo;

[0009] When the working condition inside the metal structure is non-liquid, the first low-frequency ultrasonic probe is controlled to transmit, and the second low-frequency ultrasonic probe is controlled to receive the second echo;

[0010] The working conditions inside the metal structure are determined according to the second echo and the discrimination lines of each working condition; wherein the working conditions include air, ice and concrete.

[0011] In a possible implementation, judging whether the internal working condition of the metal structure is liquid according to the echo time and the first echo amplitude includes:

[0012] Determine the gate, the first invisible gate and the second invisible gate respectively according to the echo time; wherein the echo time includes the first time, the second time and the third time, and the third time, the first time and the second time increase in sequence;

[0013] Calculate the sum of the first echo amplitudes in the gate, the first invisible gate and the second invisible gate; and determine whether the internal working condition of the metal structure is liquid based on the sum of the first echo amplitudes in the gate, the first invisible gate and the second invisible gate.

[0014] In a possible implementation, judging whether the working condition inside the metal structure is liquid according to the first echo amplitude in the gate, the first invisible gate and the second invisible gate includes:

[0015] When the first echo amplitude sum in the gate is greater than the set multiple of the first echo amplitude sum in the first invisible gate, and the first echo amplitude sum in the gate is greater than the set multiple of the first echo amplitude sum in the second invisible gate, it is judged that the working condition inside the metal structure is liquid.

[0016] In a possible implementation, determining the gate, the first invisible gate, and the second invisible gate respectively according to the echo time includes:

[0017] Determine the gate according to the first time and the second time; wherein the first time position and the second time position are respectively the first gate line and the second gate line of the gate;

[0018] Determine a fourth time according to the first time and the third time, and set a first invisible gate at the fourth time position, wherein the width of the first invisible gate is the same as the width of the gate;

[0019] The fifth time is determined according to the first time and the fourth time, and a second invisible gate is set at the position of the fifth time, and the width of the second invisible gate is the same as the width of the gate.

[0020] In a possible implementation, determining the internal working condition of the metal structure according to the second echo and the discrimination line of each working condition includes:

[0021] When the first wave signal of the second echo is at the judgment line position of the air condition, it is judged that the condition inside the metal structure is air;

[0022] When the first wave signal of the second echo is at the judgment line of ice condition, it is judged that the condition inside the metal structure is ice;

[0023] When the first wave signal of the second echo is at the judgment line position of the concrete working condition, it is judged that the working condition inside the metal structure is concrete.

[0024] In a possible implementation, the second echo includes a first sub-echo, a second sub-echo and a third sub-echo;

[0025] When the working condition inside the metal structure is non-liquid, controlling the first low-frequency ultrasonic probe to transmit, and controlling the second low-frequency ultrasonic probe to receive a second echo, including:

[0026] Controlling the first low-frequency ultrasonic probe to transmit at a first preset frequency, and controlling the second low-frequency ultrasonic probe to receive the first sub-echo, so as to detect whether the interior of the metal structure is in an air condition;

[0027] Controlling the first low-frequency ultrasonic probe to transmit at a second preset frequency, and controlling the second low-frequency ultrasonic probe to receive a second sub-echo, so as to detect whether the interior of the metal structure is in an ice condition;

[0028] The first low-frequency ultrasonic probe is controlled to transmit at a third preset frequency, and the second low-frequency ultrasonic probe is controlled to receive the third sub-echo, so as to detect whether the interior of the metal structure is in a concrete working condition.

[0029] In a possible implementation, the method further includes:

[0030] When the interior of the metal structure is concrete, the node energy ratio change rate, node energy ratio and wavelet packet singular spectrum entropy are extracted according to the second echo;

[0031] The node energy ratio change rate, node energy ratio and wavelet packet singular spectrum entropy are input into the trained SVM classifier to obtain the concrete defect recognition results; wherein the defect recognition results include normal concrete, concrete voids and concrete voids.

[0032] In a possible implementation, the process of determining the judgment line of each working condition includes:

[0033] The judgment lines of each working condition are determined according to the geometric parameters and the propagation speed of the ultrasonic wave in each working condition.

[0034] In a second aspect, an embodiment of the present invention provides an internal detection device for a closed metal structure in service, comprising:

[0035] A parameter acquisition module, used to acquire geometric parameters of the metal structure; wherein the geometric parameters include the wall thickness and outer diameter of the metal structure;

[0036] A first echo acquisition module, used to control the high-frequency ultrasonic probe to transmit high-frequency ultrasonic waves and receive a first echo;

[0037] A liquid working condition detection module is used to determine the echo time according to the geometric parameters, and judge whether the working condition inside the metal structure is liquid according to the echo time and the first echo amplitude;

[0038] A second echo acquisition module, used for controlling the first low-frequency ultrasonic probe to transmit and controlling the second low-frequency ultrasonic probe to receive a second echo when the working condition inside the metal structure is non-liquid;

[0039] The non-liquid working condition detection module is used to determine the working condition inside the metal structure according to the second echo and the discrimination line of each working condition; wherein the working conditions include air, ice and concrete.

[0040] In a third aspect, an embodiment of the present invention provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method in the first aspect or any possible implementation of the first aspect is implemented.

[0041] In the embodiment of the present invention, a high-frequency ultrasonic probe is used to transmit a high-frequency ultrasonic wave and receive a first echo, and the echo time is determined according to the geometric parameters of the metal structure. According to the echo time and the amplitude of the first echo, it is possible to quickly determine whether the interior of the closed metal structure is liquid. When there is no liquid in the metal structure, the first low-frequency ultrasonic probe is used to transmit, and the second low-frequency ultrasonic probe receives the second echo, and the internal working condition of the metal structure is quickly determined according to the second echo and the discrimination line. Through efficient data acquisition, precise parameter setting and multi-path signal analysis, rapid liquid judgment and multiple working condition distinction are performed, and repeated operations and unnecessary data processing in the detection process are reduced, thereby achieving rapid and high-precision detection of the internal conditions of the closed metal structure, and being applicable to multiple working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a flowchart of the internal inspection process of a closed metal structure in service provided by an embodiment of the present invention;

[0043] Figure 2 It is a schematic diagram of the ultrasonic wave propagation path inside the closed metal structure in service when detecting liquid provided by an embodiment of the present invention;

[0044] Figure 3 It is a flow chart of the implementation of the internal detection method of the closed metal structure in service provided by the embodiment of the present invention;

[0045] Figure 4 It is a schematic diagram of water echo judgment for liquid detection provided by an embodiment of the present invention;

[0046] Figure 5 It is a schematic diagram of judging working conditions when the interior of a metal structure is filled with air, ice and concrete, provided by an embodiment of the present invention;

[0047] Figure 6 It is a schematic diagram of the structure of the internal detection device of the closed metal structure in service provided by an embodiment of the present invention;

[0048] Figure 7is a schematic diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0049] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0050] Figure 1 A flowchart of the internal detection process of a closed metal structure in service provided by an embodiment of the present invention. Taking water as an example of the internal liquid, water is first detected. Ultrasonic waves propagate quickly in water and have little attenuation. A high-frequency ultrasonic probe can be used in a spontaneous and self-receiving mode to detect whether there is water inside the closed metal structure. If it is determined that there is an echo of accumulated water, the inside is water; if no accumulated water is detected, the low-frequency mode is switched to use a low-frequency ultrasonic probe for the next step of judgment. The judgment line at the first wave position can be used to determine whether the inside is ice, air or concrete. If it is concrete, the state of the concrete can be further determined by the SVM classifier.

[0051] Figure 2 A schematic diagram of ultrasonic wave propagation paths inside a closed metal structure in service when detecting liquids provided by an embodiment of the present invention. Closed metal structures include closed columns, pipes, steel boxes, spheres, pressure vessels, etc. Metal structures include materials with good transmission properties such as steel structures and aluminum alloys.

[0052] Assume that the outer diameter of the metal structure is D, the wall thickness is d, the speed of ultrasonic wave in the metal structure is c1, the speed of ultrasonic wave in water is v2, the speed of guided wave in the metal structure is v3, the water accumulation detection probe is 1-5MHz, and the propagation path of ultrasonic wave in the metal structure is as follows: Figure 2 As shown, path one ( Figure 2 The black line (①) inside the metal is the high-frequency ultrasonic probe emitting ultrasonic waves on one side of the metal structure. The ultrasonic waves pass through the outer wall of the metal structure, enter the inside of the metal structure, reach the inner surface on the other side of the metal structure, and then return to the high-frequency ultrasonic probe; Path 2 ( Figure 2 The red line (②) inside the metal is similar to path 1, but the difference is that path 2 returns to the high-frequency ultrasonic probe after the high-frequency ultrasonic wave reaches the outer wall on the other side of the metal structure. Therefore, the distance of path 2 is longer than that of path 1 by the thickness of the wall of two metal structures. Figure 2 The blue line ③ inside the metal is the high-frequency ultrasonic probe emitting ultrasonic waves on one side of the metal structure. The ultrasonic waves go around the inside of the wall of the metal structure and return to the high-frequency ultrasonic probe.

[0053] See also Figure 3 , which shows a flow chart of the implementation of the internal detection method of the closed metal structure in service provided by the embodiment of the present invention, and is described in detail as follows:

[0054] Step 301: Acquire geometric parameters of a metal structure; wherein the geometric parameters include the wall thickness and outer diameter of the metal structure.

[0055] In this embodiment, the wall thickness refers to the thickness of the metal structure, that is, the distance from the outer surface to the inner surface. The outer diameter refers to the outer diameter of the metal structure. Before detecting the internal condition of the metal structure, it is necessary to obtain the geometric parameters of the metal structure. The geometric parameters affect the propagation path and time of the ultrasonic wave, thereby affecting the accuracy of the detection result, which is very important for subsequent ultrasonic detection.

[0056] Step 302: Control the high-frequency ultrasonic probe to transmit high-frequency ultrasonic waves and receive the first echo.

[0057] In this embodiment, the high-frequency ultrasonic probe is a specially designed device that can transmit and receive high-frequency ultrasonic signals. High-frequency ultrasonic waves are usually used for detection, have high resolution, and can detect subtle structural changes more accurately. By controlling the probe to generate and transmit high-frequency ultrasonic waves, the ultrasonic waves will pass through the outer wall of the metal structure and enter the interior of the metal structure. The emitted ultrasonic waves will be reflected back when encountering different media inside the metal structure (such as liquid, air, ice, concrete, etc.). The probe can not only transmit ultrasonic waves, but also receive reflected echoes. By analyzing the characteristics of these echoes (such as time, amplitude, etc.), the conditions inside the metal structure can be judged.

[0058] Step 303: Determine the echo time according to the geometric parameters, and judge whether the internal working condition of the metal structure is liquid according to the echo time and the first echo amplitude.

[0059] In this embodiment, the propagation path of the ultrasonic wave in the metal structure and the expected echo time can be calculated according to the wall thickness and outer diameter of the metal structure. For example, the propagation path of the ultrasonic wave in the metal structure can be directly through the pipe wall (path one and path two), or go around the pipe wall and return to the probe (path three).

[0060] In this embodiment, if a strong echo (high amplitude) is received within the expected time (calculated by the geometric parameters), it may indicate that there is liquid inside. If a strong echo is not received within the expected time, it may indicate that the inside is not liquid, but other substances such as air, ice or concrete.

[0061] Step 304: When the working condition inside the metal structure is non-liquid, the first low-frequency ultrasonic probe is controlled to transmit, and the second low-frequency ultrasonic probe is controlled to receive the second echo.

[0062] In this embodiment, the first low-frequency ultrasonic probe refers to a low-frequency ultrasonic probe, which usually has a low frequency (e.g., tens of kHz to hundreds of kHz) and is suitable for detecting non-liquid media. This low-frequency probe is controlled to emit ultrasonic signals. The propagation characteristics of low-frequency ultrasonic waves in non-liquid media are different from those of high-frequency ultrasonic waves, which are suitable for further distinguishing different non-liquid working conditions. The second low-frequency ultrasonic probe is another low-frequency ultrasonic probe, which is used to receive echo signals, and receives echo signals obtained by the ultrasonic waves emitted by the first low-frequency probe passing through the inside of the metal structure. This echo signal will be used to further analyze the properties of the internal medium. The first low-frequency ultrasonic wave and the second low-frequency ultrasonic wave are respectively located on both sides of the metal structure.

[0063] Step 305: Determine the internal working condition of the metal structure according to the second echo and the discrimination line of each working condition; wherein the working conditions include air, ice and concrete.

[0064] In this embodiment, the second echo is an echo signal received by the second low-frequency ultrasonic probe, and contains information after the ultrasonic wave propagates inside the metal structure. The discrimination lines of each working condition are pre-set reference lines used to distinguish different internal working conditions (air, ice, concrete), and these discrimination lines are calculated based on the propagation speed and characteristics of ultrasonic waves in different media.

[0065] In the embodiment of the present invention, based on the propagation characteristics of ultrasound, since the propagation characteristics of ultrasound in different objects are different, a judgment line is automatically generated, and intelligent judgment of the internal state can be achieved; it can quickly and accurately judge whether the internal condition is hollow, whether there is liquid accumulation (water accumulation), whether there is internal ice in winter or in cold areas, whether there is building concrete, and can further detect whether the concrete is hollow or has holes.

[0066] In a possible implementation, judging whether the internal working condition of the metal structure is liquid according to the echo time and the first echo amplitude includes:

[0067] Determine the gate, the first invisible gate and the second invisible gate respectively according to the echo time; wherein the echo time includes the first time, the second time and the third time, and the third time, the first time and the second time increase in sequence;

[0068] Calculate the sum of the first echo amplitudes in the gate, the first invisible gate and the second invisible gate; and determine whether the internal working condition of the metal structure is liquid based on the sum of the first echo amplitudes in the gate, the first invisible gate and the second invisible gate.

[0069] In this embodiment, a time window (gate) is set according to the propagation path of the ultrasonic wave in the metal structure and the expected echo time. The gate line of the gate is used to limit the position where the water accumulation echo appears. The appearance of a large echo within the gate line indicates that there is water accumulation inside. The gate width can ensure that if there is water accumulation echo, it will appear within the gate line. In addition to the main gate, two invisible gates, the first invisible gate and the second invisible gate, are set to detect other possible echo paths. The positions and widths of these invisible gates are equal to the gates. In each gate (including the invisible gate), calculating the sum of the amplitudes of the echo signals can help distinguish the reflection characteristics of different media. By comparing the sum of the echo amplitudes in the gate and the invisible gate, the properties of the internal medium can be judged. For example, if the sum of the echo amplitudes in the gate is much larger than the sum of the echo amplitudes in the invisible gate, it may indicate that the interior is liquid.

[0070] In this embodiment, the invisible gate is not displayed on the waveform diagram. In order to prevent the echo received by path three from affecting the judgment, the invisible gate is set to perform amplitude processing. In order to prevent misjudgment, two invisible gates are set, thereby setting multiple conditions to determine whether there is water accumulation.

[0071] In a possible implementation, judging whether the working condition inside the metal structure is liquid according to the first echo amplitude in the gate, the first invisible gate and the second invisible gate includes:

[0072] When the first echo amplitude sum in the gate is greater than the set multiple of the first echo amplitude sum in the first invisible gate, and the first echo amplitude sum in the gate is greater than the set multiple of the first echo amplitude sum in the second invisible gate, it is judged that the working condition inside the metal structure is liquid.

[0073] In this embodiment, for example, when the amplitude of the first echo inside the gate is greater than 10 times the amplitude of the first echo inside the first invisible gate, and the amplitude of the first echo inside the gate is greater than 10 times the amplitude of the first echo inside the second invisible gate, it can be determined that the interior of the metal structure is liquid (such as water).

[0074] In this embodiment, it is known from the propagation path of the ultrasonic wave inside the metal structure that the waveform amplitude during the period from the third time to the first time should be substantially 0. Since noise may appear due to the influence of vibration, the sum of the noise amplitude in the middle part is calculated as the sum of the first echo amplitude and H2 in the first invisible gate. If there is water accumulation inside, the amplitude of the first echo and H1 in the gate will be very large, and the minimum limit H1>10H2 is set. If this condition is met, and the relationship between the sum of the first echo amplitude and H1 in the same gate and the sum of the first echo amplitude and H3 in the second invisible gate satisfies H1>10H3, it is judged that there is water accumulation in the metal structure. If this condition (H1>10H2 and H1>10H3) is not met, it is judged that there is no water accumulation.

[0075] In a possible implementation, determining the gate, the first invisible gate, and the second invisible gate respectively according to the echo time includes:

[0076] Determine the gate according to the first time and the second time; wherein the first time position and the second time position are respectively the first gate line and the second gate line of the gate;

[0077] Determine a fourth time according to the first time and the third time, and set a first invisible gate at the fourth time position, wherein the width of the first invisible gate is the same as the width of the gate;

[0078] The fifth time is determined according to the first time and the fourth time, and a second invisible gate is set at the position of the fifth time, and the width of the second invisible gate is the same as the width of the gate.

[0079] In this embodiment, the gate is a time window, the start time of the gate is the first time, and the end time is the second time. Therefore, the width of the gate is the second time minus the first time. By setting the gate and the invisible gate, the echo signals of different paths can be analyzed more accurately to determine the conditions inside the metal structure. The setting of the gate and the invisible gate helps to distinguish the reflection characteristics of different media and improve the accuracy of detection.

[0080] Among them, the first time is the time for the ultrasonic wave to propagate in the metal structure along the propagation path one, and the calculation formula of the first time is:

[0081]

[0082] Where d is the wall thickness of the metal structure, D is the outer diameter of the metal structure, v1 is the speed of ultrasound in the metal structure, and v2 is the speed of ultrasound in water.

[0083] The second time is the time it takes for the ultrasonic wave to propagate in the metal structure along the second propagation path. The calculation formula for the second time is:

[0084]

[0085] The third time is the time for the ultrasonic wave to propagate in the metal structure along the propagation path three. The calculation formula of the third time is:

[0086]

[0087] Where v3 is the guided wave velocity of ultrasound in the metal structure.

[0088] In this embodiment, since the propagation speed of ultrasound in water is lower than that in metal, for example, the propagation speed of ultrasound in steel is approximately 5960 meters per second, while the propagation speed in water is approximately 1500 meters per second, the third time is lower than the first time, and the first time is lower than the second time.

[0089] In this embodiment, if there is liquid in the metal structure, a large echo will appear in the gate. Figure 4 As shown in the figure, the waveform between the two red vertical lines is the echo of accumulated water. The left and right gate lines are used to limit the location where the echo of accumulated water appears. A large echo inside the gate line indicates that there is accumulated water inside. The gate width can ensure that if there is accumulated water, the echo will appear inside the gate line.

[0090] From the propagation path of ultrasonic waves in metal structures, it can be seen that the waveform amplitude during the period of t3-t1 should be basically 0, and the middle position time is taken as t4. The calculation formula for the fourth time is:

[0091]

[0092] Wherein, t1 and t3 are the first time and the third time.

[0093] The fifth time is obtained by taking the first time as the axis of symmetry and symmetric the fourth time. The calculation formula for the fifth time is:

[0094]

[0095] Where d is the wall thickness of the metal structure, and v3 is the guided wave velocity of the ultrasonic wave in the metal structure.

[0096] In a possible implementation, determining the internal working condition of the metal structure according to the second echo and the discrimination line of each working condition includes:

[0097] When the first wave signal of the second echo is at the judgment line position of the air condition, it is judged that the condition inside the metal structure is air;

[0098] When the first wave signal of the second echo is at the judgment line of ice condition, it is judged that the condition inside the metal structure is ice;

[0099] When the first wave signal of the second echo is at the judgment line position of the concrete working condition, it is judged that the working condition inside the metal structure is concrete.

[0100] In this embodiment, the received echo signal contains the reflection information of the ultrasonic wave after propagating inside the metal structure. The discrimination lines of each working condition are pre-set reference lines used to distinguish different internal working conditions (air, ice, concrete). These discrimination lines are calculated based on the propagation speed and characteristics of ultrasonic waves in different media. The first wave signal is the first wave to arrive in the echo signal, usually the strongest wave, and is used to judge the properties of the medium. Figure 5 shown.

[0101] In a possible implementation, the second echo includes a first sub-echo, a second sub-echo and a third sub-echo;

[0102] When the working condition inside the metal structure is non-liquid, controlling the first low-frequency ultrasonic probe to transmit, and controlling the second low-frequency ultrasonic probe to receive a second echo, including:

[0103] Controlling the first low-frequency ultrasonic probe to transmit at a first preset frequency, and controlling the second low-frequency ultrasonic probe to receive the first sub-echo, so as to detect whether the interior of the metal structure is in an air condition;

[0104] Controlling the first low-frequency ultrasonic probe to transmit at a second preset frequency, and controlling the second low-frequency ultrasonic probe to receive a second sub-echo, so as to detect whether the interior of the metal structure is in an ice condition;

[0105] The first low-frequency ultrasonic probe is controlled to transmit at a third preset frequency, and the second low-frequency ultrasonic probe is controlled to receive the third sub-echo, so as to detect whether the interior of the metal structure is in a concrete working condition.

[0106] In this embodiment, the first low-frequency ultrasonic probe is used to transmit ultrasonic signals of different frequencies. The second low-frequency ultrasonic probe is used to receive echo signals. By using low-frequency ultrasonic probes of different frequencies to transmit and receive different sub-echo signals respectively, it is possible to detect whether the inside of the metal structure is air, ice or concrete. This method utilizes the propagation characteristics of ultrasonic waves in different media and uses probes of different frequencies and corresponding sub-echoes to accurately judge the internal working conditions.

[0107] In a possible implementation, the method further includes:

[0108] When the interior of the metal structure is concrete, the node energy ratio change rate, node energy ratio and wavelet packet singular spectrum entropy are extracted according to the second echo;

[0109] The node energy ratio change rate, node energy ratio and wavelet packet singular spectrum entropy are input into the trained SVM classifier to obtain the concrete defect recognition results; wherein the defect recognition results include normal concrete, concrete voids and concrete voids.

[0110] In this embodiment, if the detected first wave signal is near the concrete judgment line, it is necessary to further detect whether concrete voids or holes are generated. The time-frequency information of the ultrasonic wave is used to extract the node energy ratio change rate based on the wavelet packet theory. The node energy ratio and the wavelet packet singular entropy characterize different defect types, and a feature vector is constructed as the input of the SVM classifier to realize defect identification.

[0111] Among them, the node energy ratio change is a measure of the energy difference between the wavelet packet nodes of two signals and is defined as follows:

[0112]

[0113] WPD i represents the rate of change of wavelet packet energy of the i-th node signal in the j-th layer, Represents the average value of the wavelet packet energy change rate of all node signals in the jth layer.

[0114] WPD i The definition is as follows:

[0115]

[0116] WP i R and WP i M They represent the wavelet packet energies of the reference signal and the comparison signal at the i-th node in the j-th layer respectively.

[0117] The node energy ratio indicates the proportion of the wavelet packet signal in each frequency domain segment.

[0118]

[0119] Where L represents the number of wavelet packet decomposition layers, z n and N L They represent the amplitude and number of sampling points of the reconstructed signal respectively.

[0120] Wavelet packet singular spectrum entropy decomposes the node signal reconstructed by wavelet packet decomposition into singular values ​​that can reflect the characteristics of the original signal, and then uses the statistical characteristics of information entropy to characterize the original signal. Since the collected signal may contain noise information, before calculating the wavelet packet singular entropy, some low-correlation node signals are removed by the Pearson correlation coefficient to reduce noise interference. The calculation method of the Pearson correlation coefficient is as follows:

[0121]

[0122] Where Q and O represent the node signal and the original signal respectively. i and iRepresent the sampling point amplitudes of the node signal and the original signal respectively. If σ Q,O ≥0.3, the singular entropy of the node signal is calculated according to the formula. Otherwise, the singular entropy of the node signal is set to 0.

[0123] Wavelet packet decomposition can be expressed as:

[0124]

[0125] in: is the lth coefficient value in the nth unit node in the kth wavelet packet decomposition layer, h(l-2i) is a low-pass filter, and f(l-2i) is a high-pass filter.

[0126] The signal is formed into an m×n dimensional matrix, and the singular value decomposition is performed on it. The singular value obtained by the decomposition is τ i (i=1,2,…g), for τ i Arrange in descending order and define the singular spectral entropy as:

[0127]

[0128]

[0129] The above signal features are input into the SVM classifier, and the concrete defects are identified according to the signal feature classification results output by the classifier.

[0130] In a possible implementation, the process of determining the judgment line of each working condition includes:

[0131] The judgment lines of each working condition are determined according to the geometric parameters and the propagation speed of the ultrasonic wave in each working condition.

[0132] In this embodiment, when the metal structure is filled with air, a low-frequency ultrasonic probe with a frequency of f1 is used for detection. The ultrasonic wave propagates along the metal structure wall as a guided wave. By drawing a dispersion curve, the guided wave sound velocity value can be obtained. The first wave sound time of the ultrasonic wave propagating when the inside is air is:

[0133]

[0134] Where d is the wall thickness of the metal structure, and v3 is the guided wave velocity.

[0135] Input the guided wave sound velocity value and set the position t5 as the air discrimination line.

[0136] When the metal structure is filled with ice, a low-frequency ultrasonic probe with a frequency of f2 is used for detection. The ultrasonic wave propagates along the diameter at v4, and the first wave sound time is:

[0137]

[0138] Where d is the wall thickness of the metal structure, D is the outer diameter of the metal structure, and v1 is the speed of ultrasound in the metal structure.

[0139] Input the sound velocity value in ice, and the ice discrimination line will be automatically generated at t6. In actual operation, if there is a gap between ice and the pipe wall, the waveform propagating in the pipe wall will be detected, and the internal ice cannot be detected.

[0140] When the metal structure is filled with concrete, an ultrasonic probe with a frequency of f3 is used for detection. The ultrasonic wave propagates along the diameter at v5, and the first wave sound time is:

[0141]

[0142] Where d is the wall thickness of the metal structure, D is the outer diameter of the metal structure, and v1 is the speed of ultrasound in the metal structure.

[0143] Input the sound velocity value in concrete, and the concrete judgment line will be automatically generated at t7.

[0144] In this embodiment, different discrimination lines are generated by the different sound velocities of ultrasonic waves propagating in different internal conditions, and the internal conditions are judged according to the discrimination lines at the positions of the first waves.

[0145] In the embodiment of the present invention, a method for intelligently distinguishing the internal conditions of a closed metal structure by using a high-efficiency and high-precision ultrasonic detection method is proposed. A method for generating an intelligent discrimination line for distinguishing different internal conditions; the position of the discrimination line can be automatically calibrated by setting parameters according to different internal conditions; the ultrasonic detection method can be used for comprehensive detection of different metal materials and multiple internal conditions; and the SVM concrete defect recognition algorithm based on wavelet packet theory feature extraction.

[0146] In other possible implementations, SVM, node energy ratio change rate, node energy ratio and wavelet packet singular spectral entropy may be implemented in other ways. This application mainly uses SVM, node energy ratio change rate, node energy ratio and wavelet packet singular spectral entropy as examples for illustration.

[0147] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0148] The following is an embodiment of the device of the present invention. For details not described in detail therein, reference may be made to the corresponding method embodiment described above.

[0149] Figure 6The schematic diagram of the structure of the internal detection device of the closed metal structure in service provided by the embodiment of the present invention is shown. For the convenience of description, only the part related to the embodiment of the present invention is shown, which is described in detail as follows:

[0150] like Figure 6 As shown, the internal detection device 6 of the closed metal structure in service includes:

[0151] A parameter acquisition module 61 is used to acquire geometric parameters of the metal structure; wherein the geometric parameters include the wall thickness and outer diameter of the metal structure;

[0152] A first echo acquisition module 62, used to control the high-frequency ultrasonic probe to transmit high-frequency ultrasonic waves and receive a first echo;

[0153] A liquid condition detection module 63, used to determine the echo time according to the geometric parameters, and judge whether the internal condition of the metal structure is liquid according to the echo time and the first echo amplitude;

[0154] A second echo acquisition module 64, for controlling the first low-frequency ultrasonic probe to transmit and controlling the second low-frequency ultrasonic probe to receive a second echo when the working condition inside the metal structure is non-liquid;

[0155] The non-liquid working condition detection module 65 is used to determine the working condition inside the metal structure according to the second echo and the discrimination line of each working condition; wherein the working conditions include air, ice and concrete.

[0156] In a possible implementation, the liquid condition detection module 63 may be used to:

[0157] Determine the gate, the first invisible gate and the second invisible gate respectively according to the echo time; wherein the echo time includes the first time, the second time and the third time, and the third time, the first time and the second time increase in sequence;

[0158] Calculate the sum of the first echo amplitudes in the gate, the first invisible gate and the second invisible gate; and determine whether the internal working condition of the metal structure is liquid based on the sum of the first echo amplitudes in the gate, the first invisible gate and the second invisible gate.

[0159] In a possible implementation, the liquid condition detection module 63 may be used to:

[0160] When the first echo amplitude sum in the gate is greater than the set multiple of the first echo amplitude sum in the first invisible gate, and the first echo amplitude sum in the gate is greater than the set multiple of the first echo amplitude sum in the second invisible gate, it is judged that the working condition inside the metal structure is liquid.

[0161] In a possible implementation, the liquid condition detection module 63 may be used to:

[0162] Determine the gate according to the first time and the second time; wherein the first time position and the second time position are respectively the first gate line and the second gate line of the gate;

[0163] Determine a fourth time according to the first time and the third time, and set a first invisible gate at the fourth time position, wherein the width of the first invisible gate is the same as the width of the gate;

[0164] The fifth time is determined according to the first time and the fourth time, and a second invisible gate is set at the position of the fifth time, and the width of the second invisible gate is the same as the width of the gate.

[0165] In a possible implementation, the non-liquid condition detection module 65 may be used to:

[0166] When the first wave signal of the second echo is at the judgment line position of the air condition, it is judged that the condition inside the metal structure is air; the second echo includes the first sub-echo, the second sub-echo and the third sub-echo;

[0167] When the first wave signal of the second echo is at the judgment line of ice condition, it is judged that the condition inside the metal structure is ice;

[0168] When the first wave signal of the second echo is at the judgment line position of the concrete working condition, it is judged that the working condition inside the metal structure is concrete.

[0169] In a possible implementation, the non-liquid condition detection module 65 may be used to:

[0170] Controlling the first low-frequency ultrasonic probe to transmit at a first preset frequency, and controlling the second low-frequency ultrasonic probe to receive the first sub-echo, so as to detect whether the interior of the metal structure is in an air condition;

[0171] Controlling the first low-frequency ultrasonic probe to transmit at a second preset frequency, and controlling the second low-frequency ultrasonic probe to receive a second sub-echo, so as to detect whether the interior of the metal structure is in an ice condition;

[0172] The first low-frequency ultrasonic probe is controlled to transmit at a third preset frequency, and the second low-frequency ultrasonic probe is controlled to receive the third sub-echo, so as to detect whether the interior of the metal structure is in a concrete working condition.

[0173] In a possible implementation, the non-liquid condition detection module 65 may be used to:

[0174] When the interior of the metal structure is concrete, the node energy ratio change rate, node energy ratio and wavelet packet singular spectrum entropy are extracted according to the second echo;

[0175] The node energy ratio change rate, node energy ratio and wavelet packet singular spectrum entropy are input into the trained SVM classifier to obtain the concrete defect recognition results; wherein the defect recognition results include normal concrete, concrete voids and concrete voids.

[0176] In a possible implementation, the non-liquid condition detection module 65 may be used to:

[0177] The judgment lines of each working condition are determined according to the geometric parameters and the propagation speed of the ultrasonic wave in each working condition.

[0178] Figure 7 Schematic diagram of an electronic device provided by an embodiment of the present invention. Figure 7 As shown, the electronic device 7 of this embodiment includes: a processor 70 and a memory 71. The memory 71 stores a computer program 72. When the processor 70 executes the computer program 72, the steps in the above-mentioned method embodiments are implemented. Alternatively, when the processor 70 executes the computer program 72, the functions of each module / unit in the above-mentioned device embodiments are implemented.

[0179] Exemplarily, the computer program 72 may be divided into one or more modules / units, which are stored in the memory 71 and executed by the processor 70 to implement the present invention. The one or more modules / units may be a series of computer program instruction segments capable of implementing specific functions, which are used to describe the execution process of the computer program 72 in the electronic device 7.

[0180] The electronic device 7 may include, but is not limited to, a processor 70 and a memory 71. Those skilled in the art will appreciate that Figure 7 It is only an example of the electronic device 7 and does not constitute a limitation of the electronic device 7. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the electronic device 7 may also include input and output devices, network access devices, buses, etc.

[0181] The processor 70 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0182] The memory 71 may be an internal storage unit of the electronic device 7, such as a hard disk or memory of the electronic device 7. The memory 71 may also be an external storage device of the electronic device 7, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the electronic device 7. Further, the memory 71 may also include both an internal storage unit of the electronic device 7 and an external storage device. The memory 71 is used to store the computer program 72 and other programs and data required by the electronic device 7. The memory 71 may also be used to temporarily store data that has been output or is to be output.

[0183] For the convenience and simplicity of description, only the division of the above functional modules / units is used as an example for illustration. In actual applications, the above functions can be assigned to different functional modules / units as needed. The above modules / units can be implemented in the form of hardware, software, or a combination of hardware and software.

[0184] The embodiment of the present invention further provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the methods in the above method embodiments are implemented.

[0185] The embodiment of the present invention further provides a computer program product, including a computer program. When the computer program is executed by a processor, the methods in the above method embodiments are implemented.

[0186] The computer program includes computer program code, which may be in source code form, object code form, executable file or some intermediate form, etc. Computer readable media may include: any entity or device capable of carrying computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc.

[0187] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments. If there is no special explanation and logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other. The technical features in different embodiments can be combined to form a new embodiment according to their internal logical relationship.

[0188] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A method for detecting the interior of a closed metal structure in service, characterized in that: include: Acquire geometric parameters of the metal structure; wherein the geometric parameters include the wall thickness and outer diameter of the metal structure; Control the high-frequency ultrasonic probe to transmit high-frequency ultrasonic waves and receive the first echo; Determine the echo time according to the geometric parameters, and judge whether the working condition inside the metal structure is liquid according to the echo time and the first echo amplitude; When the working condition inside the metal structure is non-liquid, controlling the first low-frequency ultrasonic probe to transmit, and controlling the second low-frequency ultrasonic probe to receive the second echo; The working conditions inside the metal structure are determined according to the second echo and the discrimination lines of each working condition; wherein the working conditions include air, ice and concrete.

2. The method for internal inspection of closed metal structures in service according to claim 1, characterized in that: The step of judging whether the internal working condition of the metal structure is liquid according to the echo time and the first echo amplitude includes: Determine the gate, the first invisible gate and the second invisible gate respectively according to the echo time; wherein the echo time includes the first time, the second time and the third time, and the third time, the first time and the second time increase in sequence; Calculate the sum of the first echo amplitudes in the gate, the first invisible gate, and the second invisible gate; and determine whether the internal working condition of the metal structure is liquid based on the sum of the first echo amplitudes in the gate, the first invisible gate, and the second invisible gate.

3. The method for internal inspection of closed metal structures in service according to claim 2, characterized in that: The method of judging whether the working condition inside the metal structure is liquid according to the first echo amplitude in the gate, the first invisible gate and the second invisible gate includes: When the first echo amplitude sum in the gate is greater than a set multiple of the first echo amplitude sum in the first invisible gate, and the first echo amplitude sum in the gate is greater than a set multiple of the first echo amplitude sum in the second invisible gate, it is judged that the working condition inside the metal structure is liquid.

4. The method for internal inspection of closed metal structures in service according to claim 2, characterized in that: The method of respectively determining the gate, the first invisible gate and the second invisible gate according to the echo time comprises: Determine the gate according to the first time and the second time; wherein the first time position and the second time position are respectively the first gate line and the second gate line of the gate; Determine a fourth time according to the first time and the third time, and set a first invisible gate at the fourth time position, wherein the width of the first invisible gate is the same as the width of the gate; A fifth time is determined according to the first time and the fourth time, and a second invisible gate is set at the fifth time position, wherein a width of the second invisible gate is the same as a width of the gate.

5. The method for internal inspection of closed metal structures in service according to claim 1, characterized in that: The determining the internal working condition of the metal structure according to the second echo and the discrimination line of each working condition includes: When the first wave signal of the second echo is at the position of the determination line of the air condition, it is determined that the working condition inside the metal structure is air; When the first wave signal of the second echo is at the position of the ice condition determination line, it is determined that the condition inside the metal structure is ice; When the first wave signal of the second echo is at the determination line position of the concrete working condition, it is determined that the working condition inside the metal structure is concrete.

6. The method for internal inspection of closed metal structures in service according to claim 5, characterized in that: The second echo includes a first sub-echo, a second sub-echo and a third sub-echo; When the working condition inside the metal structure is non-liquid, controlling the first low-frequency ultrasonic probe to transmit, and controlling the second low-frequency ultrasonic probe to receive a second echo, comprises: Controlling the first low-frequency ultrasonic probe to transmit at a first preset frequency, and controlling the second low-frequency ultrasonic probe to receive a first sub-echo, so as to detect whether the interior of the metal structure is in an air condition; Controlling the first low-frequency ultrasonic probe to transmit at a second preset frequency, and controlling the second low-frequency ultrasonic probe to receive a second sub-echo, so as to detect whether the interior of the metal structure is in an ice condition; The first low-frequency ultrasonic probe is controlled to transmit at a third preset frequency, and the second low-frequency ultrasonic probe is controlled to receive a third sub-echo, so as to detect whether the interior of the metal structure is in a concrete working condition.

7. The method for internal inspection of closed metal structures in service according to claim 5, characterized in that: The method further comprises: When the interior of the metal structure is concrete, extracting the node energy ratio change rate, the node energy ratio and the wavelet packet singular spectrum entropy according to the second echo; The node energy ratio change rate, the node energy ratio and the wavelet packet singular spectrum entropy are input into a trained SVM classifier to obtain a concrete defect recognition result; wherein the defect recognition result includes normal concrete, concrete voids and concrete voids.

8. The method for internal inspection of closed metal structures in service according to claim 1, characterized in that: The process of determining the judgment line of each working condition includes: The judgment lines of each working condition are determined according to the geometric parameters and the propagation speed of the ultrasonic wave in each working condition.

9. A device for detecting the interior of a closed metal structure in service, characterized in that: include: A parameter acquisition module, used to acquire geometric parameters of the metal structure; wherein the geometric parameters include the wall thickness and outer diameter of the metal structure; A first echo acquisition module, used to control the high-frequency ultrasonic probe to transmit high-frequency ultrasonic waves and receive a first echo; a liquid working condition detection module, used to determine the echo time according to the geometric parameters, and judge whether the working condition inside the metal structure is liquid according to the echo time and the first echo amplitude; A second echo acquisition module, used for controlling the first low-frequency ultrasonic probe to transmit and controlling the second low-frequency ultrasonic probe to receive a second echo when the working condition inside the metal structure is non-liquid; The non-liquid working condition detection module is used to determine the working condition inside the metal structure according to the second echo and the discrimination line of each working condition; wherein the working condition includes air, ice and concrete.

10. An electronic device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the method according to any one of claims 1 to 8 when executing the computer program.

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