Crack detection method for stone cultural relics based on concrete ultrasonic tomography scanner

Abstract

The present invention relates to the field of crack detection technology, and more specifically to a method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner. The present invention obtains crack characteristic values based on the number and signal strength differences of ultrasonic signals received by each fault probe at each moment, as well as the degree of fluctuation of the acoustic path length of the ultrasonic signal; obtains crack probability based on the signal strength and round-trip time differences of the ultrasonic signal received by each probe at each moment, as well as the crack characteristic value; and adjusts the crack probability using the degree of fluctuation of the crack probability of each probe's adjacent probes to obtain a corrected crack probability; obtains crack probability based on the difference in the corrected crack probability of each probe and its adjacent probes within a historical analysis period at each moment, thereby performing crack detection on stone cultural relics. The present invention takes into account the interference signals generated by cracks within cultural relics, thereby improving the accuracy of crack detection within cultural relics.

Description

Technical Field

[0001] The present invention relates to the technical field of crack detection, and in particular to a method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner. Background Art

[0002] Stone artifacts often possess extremely high historical, cultural, and artistic value. Ultrasonic tomography (UTM) testing is an advanced, non-contact, non-destructive technology. When using UTM to detect cracks in stone artifacts, it eliminates the need to contact the surface, thus avoiding risks such as surface scratches, structural disturbances, or chemical contamination. Furthermore, the testing process does not introduce any physical or chemical changes, allowing for repeated, long-term testing of the same artifact.

[0003] Ultrasound propagates in a straight line within stone artifacts, but cracks within the artifacts cause changes in the dielectric medium, causing the ultrasound to diffract through the cracks and propagate, delaying its reception. Existing methods for crack detection in stone artifacts rely on the propagation time of ultrasonic signals. However, the scattering and reflection of ultrasound within the cracks of the artifacts generate a large amount of internal interference signals. This interference also occurs in the received ultrasound, making it easy to misidentify cracks or obscure the signal's presence, reducing the accuracy of crack detection within artifacts. Summary of the Invention

[0004] In order to solve the technical problem of inaccurate crack detection in cultural relics due to reflection and scattering of ultrasonic waves at the crack position, the purpose of the present invention is to provide a method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner. The technical solution adopted is as follows:

[0005] The present invention proposes a method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner, the method comprising:

[0006] When a concrete ultrasonic tomography scanner is used to perform tomography on stone cultural relics, the ultrasonic signal received by the probe scanning each fault at each moment during the acquisition period, as well as the signal strength, round-trip time, and acoustic path length of the ultrasonic signal, are obtained;

[0007] According to the number and signal strength difference of the ultrasonic signals received by the probe of each fault at each moment, as well as the fluctuation degree of the acoustic path length of the ultrasonic signal, the crack characteristic value of the corresponding probe at each moment is obtained;

[0008] Obtaining the crack probability of each probe at each moment based on the signal strength of the ultrasonic signal received by each probe at each moment, the difference in round-trip time, and the crack characteristic value; and adjusting the crack probability of each probe at each moment using the difference in the crack probability between each probe and its adjacent probe to obtain a corrected crack probability;

[0009] Based on the similarity of the corrected crack probabilities of each probe and its adjacent probes during the historical analysis period at each moment, and the difference in crack characteristics of each probe at adjacent moments during the historical analysis period at each moment, the crack probability of each probe at each moment is obtained; based on the said crack probabilities of the probes on the same fault plane, crack detection is performed on stone cultural relics.

[0010] Furthermore, obtaining the crack characteristic value of the corresponding probe at each moment includes:

[0011] Obtaining the signal strength of the ultrasonic wave emitted by the scanner during tomographic scanning, recording it as a standard strength; and taking the difference between the standard strength and the signal strength of the ultrasonic signal as the ultrasonic loss;

[0012] The ultrasonic signal corresponding to the minimum round trip time is selected from the ultrasonic signals received by the probe at each moment as the direct wave;

[0013] Obtaining the abnormal loss degree of the probe at each moment based on the ultrasonic loss of the direct wave and other ultrasonic signals received by the probe at each moment, as well as the number of ultrasonic signals;

[0014] The acoustic path length corresponding to the direct wave is recorded as the ideal path length; the standard deviation of the absolute value of the difference between the acoustic path length of all ultrasonic signals received by the probe at each moment and the ideal path length is normalized to obtain the distance fluctuation of the probe at each moment;

[0015] The abnormal loss degree and the distance fluctuation degree constitute a characteristic vector of the probe at each moment; the modulus of the characteristic vector is used as the crack characteristic value of the probe at each moment.

[0016] Furthermore, obtaining the crack probability of each probe at each moment includes:

[0017] Obtaining the initial probability of the probe at each moment based on the signal strength of the ultrasonic signal received by the probe at each moment, the difference in round-trip time, and the crack characteristic value;

[0018] The ratio of the ultrasonic signals of each signal strength to the total ultrasonic signals received by the probe at each moment is counted, recorded as the signal strength ratio of each signal strength. The absolute value of the difference between the signal strengths corresponding to each two signal strength ratios is calculated, and the average of all the absolute values of the differences is calculated to obtain the intensity difference.

[0019] The crack probability of the probe at each moment is obtained according to the intensity difference and the initial probability.

[0020] Furthermore, obtaining the initial probability of the probe at each moment includes:

[0021] Selecting the ultrasonic signal with the minimum signal intensity from the ultrasonic signals received by the probe at each moment as the maximum intensity signal;

[0022] Calculate the absolute value of the difference between the round-trip time of the direct wave and the maximum intensity signal received by the probe at each moment, and the absolute value of the difference in signal intensity, and use the product of the two absolute values of the difference as the signal difference;

[0023] The initial probability of the probe at each moment is obtained according to the signal difference and the crack characteristic value.

[0024] Furthermore, the method for obtaining the corrected crack probability includes:

[0025] The cumulative sum of the differences between the crack probability of each probe and its adjacent probes at each moment is normalized, and the crack probability of each probe at each moment is weighted using the processing result to obtain the corrected crack probability of each probe at each moment.

[0026] Furthermore, obtaining the crack probability of each probe at each moment includes:

[0027] Calculating the cosine similarity of the feature vectors of each probe at every two adjacent moments in the historical analysis period at each moment, performing negative correlation mapping on the cumulative sum of all cosine similarities, and obtaining the signal disorder degree of each probe at each moment;

[0028] According to the difference in the corrected crack probability of each probe and its adjacent probes at all times during the historical analysis period at each time, the neighborhood signal similarity of each probe at each time is obtained;

[0029] The crack probability of each probe at each moment is obtained according to the mean value of the corrected crack possibility of the crack sequence of each probe at each moment, the signal disorder and the neighborhood signal similarity.

[0030] Furthermore, the crack detection of stone cultural relics based on the crack probability of the probes on the same fault plane includes:

[0031] Determine whether the crack probability of all probes of each fault at all times during the acquisition period meets the preset conditions. If so, there is no crack in each fault; otherwise, there is a crack in each fault.

[0032] The preset conditions are: the crack probability of all probes in each fault at all times during the acquisition period is less than the preset crack threshold, and the range of all crack probabilities is less than the preset fluctuation threshold.

[0033] Furthermore, obtaining the neighborhood signal similarity of each probe at each moment includes:

[0034] The corrected crack probabilities of each probe at all moments in the historical analysis period at each moment are arranged in time sequence to obtain the crack sequence of each probe at each moment; the cumulative sum of the cosine similarities of the crack sequence of each probe and its adjacent probes at each moment is calculated as the neighborhood signal similarity of each probe at each moment.

[0035] Furthermore, the mean value of the corrected crack possibility of the crack sequence of each probe at each moment, the signal disorder and the neighborhood signal similarity are all positively correlated with the crack probability.

[0036] Furthermore, the preset crack threshold is 0.87.

[0037] The present invention has the following beneficial effects:

[0038] In an embodiment of the present invention, the signal characteristics of possible cracks are analyzed for the ultrasonic signal of each probe at each moment, thereby obtaining a crack characteristic value representing the crack characteristics of the stone cultural relic; at the same time, the crack signal characteristics of each probe are compared with those of the adjacent probes to verify whether the crack characteristic value of each probe is accurate, and based on the degree of fluctuation of the crack probability of the adjacent probes of each probe, the crack probability of each probe at each moment is corrected to obtain a corrected crack probability, so as to improve the accuracy of ultrasonic analysis in detecting cracks in stone cultural relics; the crack probability of each probe at each moment is analyzed by utilizing the instability of the crack characteristics in time sequence and the signal changes of the adjacent probe positions, and crack detection of the stone cultural relic is realized based on the crack probability, thereby improving the accuracy of crack detection in stone cultural relics and improving the accuracy rate of crack detection in stone cultural relics. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 A flowchart of a method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner is provided in accordance with one embodiment of the present invention;

[0041] Figure 2 A flow chart of a method for obtaining crack probability provided by one embodiment of the present invention;

[0042] Figure 3 A flow chart of a method for obtaining crack probability provided by one embodiment of the present invention;

[0043] Figure 4 A computer device schematic diagram of a stone cultural relic crack detection device based on a concrete ultrasonic tomography scanner provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0044] To further illustrate the technical means and effectiveness of the present invention in achieving its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, describes in detail the specific implementation, structure, features, and effectiveness of the method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner. In the following description, references to different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0045] Unless defined otherwise, 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 belongs.

[0046] The specific scheme of the stone cultural relic crack detection method based on the concrete ultrasonic tomography scanner provided by the present invention is described in detail below with reference to the accompanying drawings.

[0047] Example 1:

[0048] This paper proposes a method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner. Figure 1 , which shows a flowchart of a method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner provided by one embodiment of the present invention, the method comprising:

[0049] Step S1: When a concrete ultrasonic tomography scanner performs tomography scanning on stone cultural relics, the ultrasonic signal received by the probe scanning each fault at each moment in the acquisition period is obtained, as well as the signal strength, round-trip time and acoustic path length of the ultrasonic signal.

[0050] A concrete ultrasonic tomography scanner was used to perform tomographic scanning of stone artifacts. The scanner's multiple dry-point contact sensors served as probes, each with independent pulse transmission and reception channels. The scanner's probes were controlled to sequentially transmit ultrasonic waves to each fault of the stone artifact. The probes collected ultrasonic signals at a 10 MHz sampling frequency. The ultrasonic signals received by the probe scanning each fault during the acquisition period between each moment and the previous moment were recorded as the ultrasonic signals received by the probe scanning each fault at each moment. The signal strength, round-trip time, and acoustic path length of the ultrasonic signals were also obtained. The acquisition period for each probe was determined based on the theoretical acoustic wave propagation delay for the corresponding fault.

[0051] It should be noted that the probes are spatially arranged in a planar array. Signal strength refers to the maximum amplitude of the ultrasonic signal, and the signal strength of the ultrasonic waves emitted by the probes scanning all faults is the same. Round-trip time is the time from sending to receiving the ultrasonic signal. The acoustic path length refers to the actual propagation length of the ultrasonic wave in the medium, which is equal to the product of the ultrasonic wave's propagation speed in the stone artifact and the round-trip time. Due to interference signals such as scattering and refraction during the ultrasonic detection process, the probe may receive multiple ultrasonic signals at each moment.

[0052] In one implementation of the embodiment of the present invention, the slice step size is set to 5 centimeters.

[0053] Step S2: According to the number and signal strength difference of ultrasonic signals received by the probe of each fault at each moment, and the degree of fluctuation of the acoustic path length of the ultrasonic signal, the crack characteristic value of the corresponding probe at each moment is obtained.

[0054] During crack detection in stone artifacts, ultrasonic waves experience significant reflection and scattering at the crack location, increasing the number of signals received by the probe. The energy of the reflected and scattered signals is absorbed, significantly reducing the ultrasonic signal energy. Furthermore, these signals undergo multiple reflections and scattering before reaching the probe, exacerbating energy variations in the ultrasonic signals. If there are no cracks, the ultrasonic waves propagate essentially in a straight line, with less significant reflection and scattering. While this phenomenon cannot be completely avoided, the number of signals received by the probe decreases and the signal strengths remain similar. Considering that crack detection results are affected by the probe's transmission angle, or scanning angle, a normal ultrasonic signal will also experience diffraction after passing through the stone artifact. However, if the crack depth is shallow or the scanning direction is nearly parallel to the crack direction, the ultrasonic signals received by the probe will maintain high consistency, meaning similar signal strengths. However, the propagation paths of the ultrasonic signals after multiple reflections and scattering still vary significantly, resulting in significant fluctuations in the acoustic path lengths of the ultrasonic signals detecting cracks. Therefore, by combining the number and intensity differences of the ultrasonic signals received by the probe at each moment, as well as the fluctuations in the acoustic path lengths of the ultrasonic signals, we analyze the crack characteristics of each fault in the stone artifact and obtain a crack characteristic value.

[0055] Step S3: Obtain the crack probability of each probe at each moment based on the signal strength of the ultrasonic signal received by each probe at each moment, the difference in round-trip time, and the crack characteristic value; and use the difference in crack probability between each probe and its adjacent probes to adjust the crack probability of each probe at each moment to obtain a corrected crack probability.

[0056] Reflection and scattering absorb ultrasonic energy at cracks, significantly reducing the amount of sound wave energy reaching the probe. However, diffracted signals representing actual cracks have higher energy and less scattering and reflection. Furthermore, the random effects of reflection and scattering on sound waves in cracks cause the probe to receive inconsistent ultrasonic signal strength at each moment. However, the probe receives a more consistent signal strength at each moment for ultrasonic signals that have not passed through cracks. Therefore, the probability of a crack can be determined based on the signal strength of the different ultrasonic signals received by the probe at each moment, the difference in round-trip time, and the crack characteristic value. This improves the accuracy of ultrasonic analysis for detecting cracks in stone artifacts.

[0057] Stone artifacts with cracks will exhibit different ultrasonic signal characteristics at different monitoring locations. Specifically, ultrasonic waves are strongly reflected at the edges of cracks, resulting in relatively high signal strength at these edges, a phenomenon known as ultrasonic edge enhancement. When cracks are present, the crack signature of the ultrasonic signal received by each probe is greater than that of adjacent probes. Therefore, the fluctuation in the crack probability of each probe relative to its neighbors is used to adjust the crack probability of each probe at each moment, yielding a corrected crack probability.

[0058] It should be noted that in one implementation of an embodiment of the present invention, for all the probes in each fault, one probe is selected as the target probe, and the other probes in the area with a radius of one tenth of the length of the minimum circumscribed cuboid of the stone cultural relics as the center are taken as adjacent probes of the target area.

[0059] Step S4: Based on the similarity of the corrected crack probability of each probe and its adjacent probes in the historical analysis period at each moment, and the difference in crack characteristics of each probe at adjacent moments in the historical analysis period at each moment, the crack probability of each probe at each moment is obtained; based on the crack probability of the probes on the same fault plane, crack detection is performed on the stone cultural relics.

[0060] The scanning angle and crack angle of stone artifacts can also affect ultrasonic signal analysis, causing the crack signature of ultrasonic signals representing cracks to be highly similar to the crack signatures of ultrasonic signals from adjacent probes. This can lead to the modified crack probability not being sufficient to represent the true crack defect. If a crack is present, the received signal at each moment experiences reflection and scattering along different paths, resulting in differences in the ultrasonic signals at the same location at different times. However, if a crack defect is absent, the ultrasonic propagation process experiences less reflection and scattering, resulting in stable ultrasonic signals at different times at the same location, meaning the crack signatures of the ultrasonic signals are more similar. Furthermore, the greater the difference in crack signatures between the ultrasonic signals received by each probe and its adjacent probes within a local time period—the smaller the similarity—the greater the probability of a crack at that probe's location. Therefore, by combining the similarity of the modified crack probability between each probe and its adjacent probes within each historical analysis period, as well as the difference in crack signatures between each probe within each historical analysis period, the presence of a crack on each probe is analyzed to determine the crack probability. Based on the crack probabilities of probes within the same fault plane, the presence of a crack on each fault in the stone artifact is determined. After completing the tomography scan of the entire stone artifact: visualize the two-dimensional tomography image of each fault, and reconstruct it through the three-dimensional imaging software idealViwer3D to visualize the cracks within the stone artifact.

[0061] In one implementation of the embodiment of the present invention, each moment is the last moment in its historical analysis period, and the total number of moments in the historical analysis period is set to 4, which can be set by the implementer according to specific circumstances.

[0062] Preferably, in some possible implementation methods of the embodiments of the present invention, the method for obtaining the crack characteristic value includes: obtaining the signal intensity of the ultrasonic wave emitted by the scanner when performing tomography scanning, recorded as the standard intensity; taking the difference between the standard intensity and the signal intensity of the ultrasonic signal as the ultrasonic loss; selecting the ultrasonic signal corresponding to the minimum round-trip time from the ultrasonic signals received by the probe at each moment as the direct wave; obtaining the abnormal loss degree of the probe at each moment based on the ultrasonic loss between the direct wave received by the probe at each moment and the remaining ultrasonic signals, as well as the number of ultrasonic signals; recording the acoustic path length corresponding to the direct wave as the ideal path length; normalizing the standard deviation of the absolute value of the difference between the acoustic path length of all ultrasonic signals received by the probe at each moment and the ideal path length to obtain the distance fluctuation of the probe at each moment; forming a characteristic vector of the probe at each moment by the abnormal loss degree and the distance fluctuation; and taking the modulus of the characteristic vector as the crack characteristic value of the probe at each moment.

[0063] It should be noted that the propagation path of the sound wave propagating through the diffraction crack increases, which increases the round-trip time. The direct wave represents the signal of the real crack, and the remaining ultrasonic signals can be regarded as interference signals after reflection and scattering. Ultrasonic loss reflects the loss of acoustic energy during ultrasonic propagation. The crack location will cause severe reflection and scattering of the interference signal, which will lose more acoustic energy. The difference in signal intensity between the direct wave and the interference signal is large. The more abnormal the acoustic energy loss, the more obvious the crack characteristics at the probe location. The more ultrasonic signals the probe receives at each moment, the more abnormal the signal energy consumption after reflection and scattering, and the more obvious the crack characteristics at the probe location. In an embodiment of the present invention, the method for obtaining the abnormal loss degree is: calculate the absolute value of the difference between the signal intensity mean of the ultrasonic signals received by the probe at each moment, excluding the direct wave, and the signal intensity of the direct wave, and normalize the absolute value of the difference by the product of the number of ultrasonic signals received by the probe at each moment to obtain the abnormal loss degree of the probe at each moment. The larger the abnormal loss degree, the more obvious the crack characteristics at the probe location. It should be noted that, in the embodiment of the present invention, the Norm function is used for normalization processing, and other normalization methods such as function conversion, maximum and minimum normalization, etc. can also be selected, which are not limited here.

[0064] The ideal path length is the propagation path length of the direct wave that represents a true crack. The standard deviation of the absolute value of the difference between the acoustic path length of the ultrasonic signal received by the probe at each moment and the ideal path length measures the degree of fluctuation in the acoustic path length of the ultrasonic signal. The larger the standard deviation, the greater the fluctuation in the acoustic wave propagation path length, and the more obvious the crack characteristics at the probe location. Therefore, both abnormal loss and distance fluctuation can reflect the crack characteristics at the probe location. Together, they form a characteristic vector that represents the crack characteristics. The longer the modulus of the characteristic vector, the more obvious the crack characteristics at the probe location.

[0065] Preferably, in some possible implementations of the present invention, the method for obtaining the crack probability can be found in Figure 2 , which shows a flow chart of a method for obtaining crack probability provided by an embodiment of the present invention, the method comprising:

[0066] Step S310: Obtain the initial probability of the probe at each moment based on the signal strength of the ultrasonic signal received by the probe at each moment, the difference in round-trip time, and the crack characteristic value.

[0067] Preferably, in some possible implementation methods of the embodiments of the present invention, the method for obtaining the initial possibility includes: selecting the ultrasonic signal corresponding to the minimum signal intensity from the ultrasonic signals received by the probe at each moment as the maximum intensity signal; respectively calculating the absolute value of the difference in round-trip time between the direct wave and the maximum intensity signal received by the probe at each moment, and the absolute value of the difference in signal intensity, and taking the product of the two absolute values of the difference as the signal difference; and obtaining the initial possibility of the probe at each moment based on the signal difference and the crack characteristic value.

[0068] It should be noted that the sound waves reflected and scattered at the crack position will increase the round-trip time. At the same time, reflection, scattering, etc. will absorb the ultrasonic energy at the crack, resulting in a significant reduction in the ultrasonic energy reaching the probe. The signal energy representing the real crack after diffraction is higher and the round-trip time is shorter. Therefore, the greater the difference in signal energy and round-trip time between the direct wave and the strongest signal, the greater the possibility that cracks exist in the stone cultural relics. If the crack characteristic value is larger and the crack characteristics at the probe position are more obvious, the possibility of cracks appearing at the probe position is greater. Therefore, the crack characteristic value and the signal difference are both positively correlated with the initial possibility. In an embodiment of the present invention, the product of the signal difference of the probe at each moment and the crack characteristic value is normalized to obtain the initial possibility. In an embodiment of the present invention, the Norm function is used for normalization.

[0069] Step S320: Count the proportion of ultrasonic signals of each signal strength in all ultrasonic signals received by the probe at each moment, record it as the signal quantity ratio of each signal strength, calculate the absolute value of the difference between the signal strengths corresponding to each two signal quantity ratios, average all the absolute values of the differences, and obtain the intensity difference.

[0070] It should be noted that the sound waves are affected by random factors such as reflection and scattering in the cracks, which leads to inconsistent signal strength of the ultrasonic signals received by the probe at each moment. However, the signal strength of the ultrasonic signals that have not passed through the cracks received by the probe at each moment is highly consistent. Therefore, the greater the difference in the corresponding signal strengths of the pairwise signal quantities, the greater the difference in the signal strengths of the ultrasonic signals received by the probe at each moment, and the greater the possibility of a crack appearing at the probe position.

[0071] Step S330: Obtain the crack probability of the probe at each moment according to the intensity difference and the initial probability.

[0072] It should be noted that the greater the difference between the initial probability and the intensity, the greater the likelihood of a crack at the probe location. Therefore, both the intensity difference and the initial probability are positively correlated with the crack probability. In this embodiment of the present invention, the product of the probe's intensity difference at each moment and the initial probability is normalized to obtain the probe's crack probability at each moment. In this embodiment of the present invention, the Norm function is used for normalization.

[0073] Preferably, in some possible implementation methods of the embodiments of the present invention, the method for obtaining the corrected crack possibility includes: normalizing the cumulative sum of the differences between the crack possibility of each probe and its adjacent probes at each moment, and using the processing result to weight the crack possibility of each probe at each moment to obtain the corrected crack possibility of each probe at each moment.

[0074] It should be noted that when a crack exists, the crack signature of the ultrasonic signal received by each probe is greater than that of its neighboring probes. Therefore, the greater the cumulative sum of the differences in the crack probability between each probe and its neighboring probes at each moment, the greater the probability of a crack at that probe location, and thus the greater the corrected crack probability of each probe. In this embodiment of the present invention, a Norm function is used for normalization.

[0075] Preferably, in some possible implementations of the present invention, the method for obtaining the crack probability can be found in Figure 3 , which shows a flow chart of a method for obtaining crack probability provided by an embodiment of the present invention, the method comprising:

[0076] Step S410: Calculate the cosine similarity of the feature vectors of each probe at each two adjacent moments in the historical analysis period at each moment, perform negative correlation mapping on the cumulative sum of all cosine similarities, and obtain the signal disorder degree of each probe at each moment.

[0077] It should be noted that if a crack exists, the ultrasonic signals at the same location at different times will have different crack characteristics. The difference in crack characteristics is measured by the cosine similarity of the feature vectors at two times. The smaller the cosine similarity of the feature vectors at two adjacent times within the historical analysis period, the greater the difference in crack characteristics at those adjacent times. The more chaotic the ultrasonic signal of each probe at each time, the greater the signal chaos, and the greater the probability of a crack on each probe. In this embodiment of the present invention, the data to be processed is used as the exponent of an exponential function with a natural constant as the base to achieve a negative correlation mapping of the data to be processed.

[0078] Step S420: Obtain the neighborhood signal similarity of each probe at each moment based on the difference in the corrected crack likelihood between each probe and its adjacent probes at all moments in the historical analysis period at each moment.

[0079] Preferably, in some possible implementation methods of the embodiments of the present invention, the method for obtaining the neighborhood signal similarity includes: arranging the corrected crack possibility of each probe at all moments in the historical analysis period at each moment in time sequence to obtain the crack sequence of each probe at each moment; calculating the cumulative sum of the cosine similarities of each probe and its adjacent probes at each moment as the neighborhood signal similarity of each probe at each moment.

[0080] It should be noted that if the cosine similarity of the crack sequence between each probe and its adjacent probe at each moment is smaller, it means that the similarity of the crack characteristics of the ultrasonic signals received by each probe and its adjacent probe during the historical analysis period at each moment is smaller, and the smaller the similarity of the neighborhood signals is, the greater the probability of cracks occurring at the probe position.

[0081] Step S430: Obtain the crack probability of each probe at each moment based on the mean value of the corrected crack likelihood of the crack sequence of each probe at each moment, the signal disorder and the neighborhood signal similarity.

[0082] It should be noted that if the mean of the corrected crack possibility of the crack sequence of the probe at each moment is larger, it indicates that the continuous time of the probe position shows crack characteristics, and the probability of cracks appearing at the probe position is greater; at the same time, if the signal disorder is larger and the neighborhood signal similarity is smaller, the probability of cracks appearing at the probe is greater. Therefore, the mean of the corrected crack possibility of the crack sequence of each probe at each moment is positively correlated with the signal disorder and the crack probability, and the neighborhood signal similarity is negatively correlated with the crack probability. In an embodiment of the present invention, a negative correlation mapping is performed on the signal disorder of each probe at each moment, and the product of the mapping result, the neighborhood signal similarity and the mean of the corrected crack possibility of the crack sequence of each probe at each moment is normalized to obtain the crack probability of each probe at each moment. In an embodiment of the present invention, the data to be processed is taken as the exponent of an exponential function with a natural constant as the base to achieve negative correlation mapping of the data to be processed; and the normalization is performed using the Norm function.

[0083] Preferably, in some possible implementation methods of the embodiments of the present invention, the crack detection method includes: determining whether the crack probability of all probes of each fault at all times within the acquisition period meets a preset condition, if so, no crack exists in each fault, otherwise, there is a crack in each fault; the preset condition is: the crack probability of all probes of each fault at all times within the acquisition period is less than a preset crack threshold, and the range of all crack probabilities is less than a preset fluctuation threshold.

[0084] In one implementation of the embodiment of the present invention, the preset crack threshold is 0.87, and the preset fluctuation threshold is set to 0.2.

[0085] So far, the present invention is completed.

[0086] Example 2:

[0087] The present invention also proposes a computer device schematic diagram of a stone cultural relic crack detection device based on a concrete ultrasonic tomography scanner, please refer to Figure 4 The computer device includes a memory 501, a processor 502, and a computer program 503 stored in the memory 501 and running on the processor 502, wherein when the processor 502 executes the computer program 503, the computer device can execute any of the aforementioned stone cultural relic crack detection methods based on the concrete ultrasonic tomography scanner.

[0088] In addition, an embodiment of the present application also protects a device, which may include a memory and a processor, wherein the memory stores executable program code, and the processor is used to call and execute the executable program code to execute a method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner provided in an embodiment of the present application.

[0089] In this embodiment, the device can be divided into functional modules based on the above-described method examples. For example, each functional module can be mapped to a specific functional module, or two or more functions can be integrated into a single processing module. The integrated module can be implemented in hardware. It should be noted that the module division in this embodiment is illustrative and represents only a logical functional division. In actual implementation, other division methods may be used.

[0090] In the case of dividing the modules into modules corresponding to their functions, the device may further include a communication module, a signal analysis module, a complexity analysis module, a positioning module, etc. It should be noted that all relevant contents of the various steps involved in the above method embodiment can be referred to the functional description of the corresponding functional modules and will not be repeated here.

[0091] It should be understood that the device provided in this embodiment is used to execute the above-mentioned method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner, and thus can achieve the same effect as the above-mentioned implementation method.

[0092] In the case of an integrated unit, the device may include a processing module and a storage module. When the device is applied to a device, the processing module may be used to control and manage the operation of the device. The storage module may be used to support the device in executing mutual program codes, etc.

[0093] The processing module may be a processor or controller that implements or executes the various exemplary logic blocks, modules, and circuits disclosed herein. The processor may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a digital signal processor (DSP) and a microprocessor, and the like. The storage module may be a memory.

[0094] Example 3:

[0095] This embodiment also provides a computer-readable storage medium, which stores computer program code. When the computer program code runs on a computer, the computer executes the above-mentioned related method steps to implement a method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner provided in the above embodiment.

[0096] Example 4:

[0097] This embodiment also provides a computer program product. When the computer program product is run on a computer, it enables the computer to execute the above-mentioned related steps to implement a method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner provided in the above embodiment.

[0098] Among them, the device, computer-readable storage medium, computer program product or chip provided in this embodiment are all used to execute the corresponding methods provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding methods provided above, and will not be repeated here.

[0099] In the embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of modules or units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0100] It should be noted that the order in which the embodiments of the present invention are described above is for illustrative purposes only and does not necessarily represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0101] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

Claims

1. A method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner, characterized in that: The method includes: When a concrete ultrasonic tomography scanner is used to perform tomography on stone cultural relics, the ultrasonic signal received by the probe scanning each fault at each moment during the acquisition period, as well as the signal strength, round-trip time, and acoustic path length of the ultrasonic signal, are obtained; According to the number and signal strength difference of the ultrasonic signals received by the probe of each fault at each moment, as well as the fluctuation degree of the acoustic path length of the ultrasonic signal, the crack characteristic value of the corresponding probe at each moment is obtained; Obtaining the crack probability of each probe at each moment based on the signal strength of the ultrasonic signal received by each probe at each moment, the difference in round-trip time, and the crack characteristic value; and adjusting the crack probability of each probe at each moment using the difference in the crack probability between each probe and its adjacent probe to obtain a corrected crack probability; Based on the similarity of the corrected crack probabilities of each probe and its adjacent probes during the historical analysis period at each moment, and the difference in crack characteristics of each probe at adjacent moments during the historical analysis period at each moment, the crack probability of each probe at each moment is obtained; crack detection of stone cultural relics is performed based on the crack probabilities of the probes on the same fault plane; The obtaining of the crack characteristic value of the corresponding probe at each moment includes: Obtaining the signal strength of the ultrasonic wave emitted by the scanner during tomographic scanning, recording it as a standard strength; and taking the difference between the standard strength and the signal strength of the ultrasonic signal as the ultrasonic loss; The ultrasonic signal corresponding to the minimum round trip time is selected from the ultrasonic signals received by the probe at each moment as the direct wave; Obtaining the abnormal loss degree of the probe at each moment based on the ultrasonic loss of the direct wave and other ultrasonic signals received by the probe at each moment, as well as the number of ultrasonic signals; The acoustic path length corresponding to the direct wave is recorded as the ideal path length; the standard deviation of the absolute value of the difference between the acoustic path length of all ultrasonic signals received by the probe at each moment and the ideal path length is normalized to obtain the distance fluctuation of the probe at each moment; The abnormal loss degree and the distance fluctuation degree constitute a characteristic vector of the probe at each moment; the modulus of the characteristic vector is used as the crack characteristic value of the probe at each moment.

2. The method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner according to claim 1, wherein: The obtaining of the crack probability of each probe at each moment includes: Obtaining the initial probability of the probe at each moment based on the signal strength of the ultrasonic signal received by the probe at each moment, the difference in round-trip time, and the crack characteristic value; The ratio of the ultrasonic signals of each signal strength to the total ultrasonic signals received by the probe at each moment is counted, recorded as the signal strength ratio of each signal strength. The absolute value of the difference between the signal strengths corresponding to each two signal strength ratios is calculated, and the average of all the absolute values of the differences is calculated to obtain the intensity difference. The crack probability of the probe at each moment is obtained according to the intensity difference and the initial probability.

3. The method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner according to claim 2, wherein: The obtaining of the initial probability of the probe at each moment includes: Selecting the ultrasonic signal with the minimum signal intensity from the ultrasonic signals received by the probe at each moment as the maximum intensity signal; Calculate the absolute value of the difference between the round-trip time of the direct wave and the maximum intensity signal received by the probe at each moment, and the absolute value of the difference in signal intensity, and use the product of the two absolute values of the difference as the signal difference; The initial probability of the probe at each moment is obtained according to the signal difference and the crack characteristic value.

4. The method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner according to claim 1, wherein: The method for obtaining the corrected crack probability comprises: The cumulative sum of the differences between the crack probability of each probe and its adjacent probes at each moment is normalized, and the crack probability of each probe at each moment is weighted using the processing result to obtain the corrected crack probability of each probe at each moment.

5. The method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner according to claim 1, wherein: The obtaining of the crack probability of each probe at each moment includes: Calculating the cosine similarity of the feature vectors of each probe at every two adjacent moments in the historical analysis period at each moment, performing negative correlation mapping on the cumulative sum of all cosine similarities, and obtaining the signal disorder degree of each probe at each moment; According to the difference in the corrected crack probability of each probe and its adjacent probes at all times during the historical analysis period at each time, the neighborhood signal similarity of each probe at each time is obtained; The crack probability of each probe at each moment is obtained according to the mean value of the corrected crack possibility of the crack sequence of each probe at each moment, the signal disorder and the neighborhood signal similarity.

6. The method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner according to claim 1, characterized in that: The crack detection of stone cultural relics based on the crack probability of the probes on the same fault plane includes: Determine whether the crack probability of all probes of each fault at all times during the acquisition period meets the preset conditions. If so, there is no crack in each fault; otherwise, there is a crack in each fault. The preset conditions are: the crack probability of all probes in each fault at all times during the acquisition period is less than the preset crack threshold, and the range of all crack probabilities is less than the preset fluctuation threshold.

7. The method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner according to claim 5, characterized in that: The obtaining of the neighborhood signal similarity of each probe at each moment includes: The corrected crack probabilities of each probe at all moments in the historical analysis period at each moment are arranged in time sequence to obtain the crack sequence of each probe at each moment; the cumulative sum of the cosine similarities of the crack sequence of each probe and its adjacent probes at each moment is calculated as the neighborhood signal similarity of each probe at each moment.

8. The method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner according to claim 5, characterized in that: The average value of the corrected crack possibility of the crack sequence of each probe at each moment, the signal disorder and the neighborhood signal similarity are both positively correlated with the crack probability.

9. The method for detecting cracks in stone cultural relics based on a concrete ultrasonic tomography scanner according to claim 6, characterized in that: The preset crack threshold is 0.87.

Images