A method, system and device for monitoring road surface subsidence disease

Abstract

The present application relates to the technical field of material analysis, and particularly relates to a road surface subsidence disease monitoring method, system and device. The present application divides the frequency band of the ultrasonic echo signal of a target area of a road surface in a frequency domain into a plurality of sub-sections, analyzes the spectral form features of the echo signal based on the energy distribution in the sub-sections, determines the cavity subsidence scattering property of the target area of the road surface, analyzes the signal effective duration based on the wave variation of the ultrasonic echo signal, determines the time domain dispersivity of the target area of the road surface, determines the cavity subsidence discriminant factor of the target area of the road surface based on the cavity subsidence scattering property and the time domain dispersivity, and further determines whether the target area of the road surface has a subsidence disease. The present application comprehensively uses spectral form and time domain duration to identify whether the target area of the road surface has a subsidence disease, significantly improves the specificity of subsidence disease identification, and greatly reduces the false positive rate caused by complex disease confusion.

Description

Technical Field

[0001] This invention relates to the field of materials analysis technology, specifically to a method, system, and device for monitoring road subsidence. Background Technology

[0002] Road surface subsidence is a common form of road structural distress, affecting not only driving comfort and safety but also potentially indicating serious safety hazards such as voids or delamination in the subgrade or base layer. To achieve early warning and accurate assessment of road surface subsidence, non-destructive testing technologies have been widely applied. Among these, ultrasonic testing, due to its sensitivity to internal defects and penetrating power, has become a highly promising technique. As an effective non-destructive testing method, ultrasonic testing emits ultrasonic pulses into the road surface and receives the echo signals, enabling the assessment of the road's internal structure. For example, by analyzing the transit time and amplitude attenuation characteristics of the echo signals, the presence and location of internal defects can be inferred.

[0003] Existing methods for monitoring pavement defects using ultrasound mostly rely on analyzing single echo characteristics, such as detecting abnormal echo peaks to determine the presence of defects. However, in real-world road environments, precursory defects to subsidence, such as subgrade cavities, often coexist with other types of defects such as cracks, delamination, and water-damaged areas. These composite defects produce similar and overlapping responses to ultrasonic signals, creating confusing signals. For example, a sharp crack and a small cavity may both produce a recognizable echo, and traditional amplitude or time-delay analysis methods struggle to effectively distinguish their types. This leads to misjudging defects like cracks or delamination as precursors to subsidence, severely impacting monitoring accuracy. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a method, system, and device for monitoring road subsidence, the specific technical solution of which is as follows:

[0005] In a first aspect, the present invention provides a method for monitoring road subsidence, comprising the following steps:

[0006] Collect ultrasonic echo signals from the target area on the road surface;

[0007] The frequency band of the ultrasonic echo signal in the frequency domain is divided into several sub-segments. Based on the energy distribution in the sub-segments, the spectral morphology characteristics of the echo signal are analyzed to determine the scattering properties of the cavity subsidence in the target area of ​​the road surface.

[0008] Based on the fluctuations of the ultrasonic echo signal, the effective duration of the signal is analyzed to determine the temporal dispersion of the target area on the road surface.

[0009] Based on the scattering properties of the cavity subsidence and the time-domain dispersion, the cavity subsidence discrimination factor of the target area of ​​the road surface is determined.

[0010] Based on the cavity and subsidence discrimination factor, it is determined whether there is subsidence damage in the target area of ​​the road surface.

[0011] In conjunction with the first aspect mentioned above, in some possible implementations, based on the energy distribution in the sub-segments, the spectral morphology characteristics of the echo signal are analyzed to determine the scattering properties of the cavity subsidence in the target area of ​​the road surface, including:

[0012] When the frequency band of the ultrasonic echo signal is divided into several sub-segments in the frequency domain, several decomposition coefficients corresponding to each sub-segment are obtained;

[0013] Based on the aforementioned decomposition coefficients, the energy characteristic value of each sub-segment is determined;

[0014] Based on the energy characteristic values ​​and center frequencies of all sub-segments, the spectral energy offset factor of the target area of ​​the road surface is determined;

[0015] Based on the difference between the center frequency of all sub-segments and the spectral energy offset factor, and combined with the energy characteristic values ​​of all sub-segments, the scattering property of the cavity subsidence in the target area of ​​the road surface is determined.

[0016] In conjunction with the first aspect mentioned above, among some possible implementation methods, the spectral energy shift factor of the target area of ​​the road surface is determined, including:

[0017] The first accumulated value is obtained by summing the products of the energy eigenvalues ​​and center frequencies of all segments.

[0018] Determine the cumulative value of the energy characteristic values ​​of all sub-segments to obtain the second cumulative value;

[0019] The ratio of the first accumulated value to the second accumulated value is determined to obtain the spectral energy shift factor of the target area of ​​the road surface.

[0020] In conjunction with the first aspect mentioned above, among some possible implementation methods, determining the scattering properties of void subsidence in the target area of ​​the road surface includes:

[0021] Determine the difference between the center frequency of each sub-segment and the spectral energy offset factor, and determine the frequency difference value;

[0022] The cumulative value of the product of the energy characteristic values ​​of all sub-segments and the frequency difference value is determined to obtain the third cumulative value;

[0023] Based on the ratio of the third accumulated value to the second accumulated value, the scattering property of the cavity subsidence in the target area of ​​the road surface is determined.

[0024] In conjunction with the first aspect mentioned above, among some possible implementation methods, the effective duration of the signal is analyzed to determine the temporal dispersion of the target area on the road surface, including:

[0025] The effective duration of the ultrasonic echo signal is determined based on the changes in the envelope of the ultrasonic echo signal.

[0026] The temporal dispersion of the target road surface area is determined based on the difference between the effective duration and the reference effective duration corresponding to the healthy road surface area.

[0027] In conjunction with the first aspect above, among some possible implementations, determining the effective duration of the ultrasonic echo signal includes:

[0028] Based on the changes in the envelope, the peak value of the envelope is determined, and based on the peak value, the energy threshold is determined.

[0029] Searching backwards from the starting point of time, the time point at which the signal value on the envelope first rises from below the energy threshold to equal or above the energy threshold is determined as the starting time point;

[0030] The search proceeds backward from the end of time to determine the point in time when the signal value on the envelope first rises from below the energy threshold to equal to or above the energy threshold, which is then taken as the termination point.

[0031] The duration between the start time point and the end time point is taken as the effective duration of the ultrasonic echo signal.

[0032] In conjunction with the first aspect above, in some possible implementations, before dividing the frequency band of the ultrasonic echo signal into several sub-segments in the frequency domain, the method further includes preprocessing the ultrasonic echo signal. The preprocessing process includes:

[0033] The ultrasonic echo signal is bandpass filtered to obtain the filtered ultrasonic echo signal.

[0034] Baseline correction is performed on the filtered ultrasonic echo signal to obtain the preprocessed ultrasonic echo signal.

[0035] In conjunction with the first aspect above, in some possible implementations, the frequency band of the ultrasonic echo signal in the frequency domain is divided into several sub-segments, including:

[0036] The frequency band of the ultrasonic echo signal in the frequency domain is divided into several sub-bands of equal width using wavelet packet transform, and several decomposition coefficients corresponding to each sub-segment are obtained during the frequency band division process.

[0037] Secondly, the present invention also provides a monitoring device for road subsidence defects, the device comprising:

[0038] The ultrasonic signal acquisition module is used to collect ultrasonic echo signals from the target area of ​​the road surface.

[0039] The scattering analysis module is used to divide the frequency band of the ultrasonic echo signal in the frequency domain into several sub-segments, analyze the spectral morphology characteristics of the echo signal based on the energy distribution in the sub-segments, and determine the scattering properties of the cavity subsidence in the target area of ​​the road surface.

[0040] The dispersion analysis module is used to analyze the effective duration of the signal based on the fluctuation changes of the ultrasonic echo signal, and to determine the temporal dispersion of the target area of ​​the road surface.

[0041] The discrimination factor determination module is used to determine the cavity subsidence discrimination factor of the target area of ​​the road surface based on the cavity subsidence scattering and the time-domain dispersion.

[0042] The subsidence defect identification module is used to determine whether subsidence defects exist in the target area of ​​the road surface based on the cavity subsidence discrimination factor.

[0043] Thirdly, the present invention also provides a monitoring system for road subsidence defects, including a memory and a processor. The memory is used to store executable computer program code, and the processor is used to call and run the executable computer program code from the memory, causing the system to perform a road subsidence defect monitoring method according to the first aspect or any possible implementation thereof.

[0044] Fourthly, the present invention also provides a computer program product comprising: computer program code, which, when run on a computer, causes the computer to execute a method for monitoring road subsidence defects as described in the first aspect or any possible implementation thereof.

[0045] Fifthly, the present invention also provides a computer-readable storage medium storing computer program code, which, when executed on a computer, causes the computer to perform a method for monitoring road subsidence defects as described in the first aspect or any possible implementation thereof.

[0046] This invention has the following beneficial effects: On the one hand, by dividing the frequency band of the ultrasonic echo signal of the target area of ​​the road surface into several sub-segments in the frequency domain, and analyzing the spectral morphology characteristics of the echo signal based on the energy distribution in the sub-segments, the scattering property of the cavity and subsidence in the target area of ​​the road surface is determined. On the other hand, based on the fluctuation changes of the ultrasonic echo signal, the effective duration of the signal is analyzed to determine the temporal dispersion of the target area of ​​the road surface. Thus, based on the scattering property of the cavity and subsidence in the target area of ​​the road surface and the temporal dispersion, a cavity and subsidence discrimination factor is determined, and based on this discrimination factor, the presence of subsidence defects in the target area of ​​the road surface is determined. This invention obtains a cavity and subsidence discrimination factor by comprehensively considering the spectral morphology and temporal persistence of the ultrasonic echo signal of the target area of ​​the road surface. This discrimination factor can effectively distinguish between complex scattering signals caused by cavity-like body defects and specular reflection signals caused by crack-like planar defects, significantly improving the specificity of subsidence defect identification and greatly reducing the false alarm rate caused by confusion due to complex defects. Attached Figure Description

[0047] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This is a flowchart illustrating the steps of a method for monitoring road subsidence according to an embodiment of the present invention.

[0049] Figure 2 This is a schematic diagram of the structure of a monitoring device for road subsidence according to an embodiment of the present invention;

[0050] Figure 3 This is a schematic diagram of the structure of a road subsidence monitoring system according to an embodiment of the present invention. Detailed Implementation

[0051] To clearly illustrate the technical features of this solution, the invention will be described in detail below through specific embodiments and in conjunction with the accompanying drawings.

[0052] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the invention. It should be understood that the accompanying drawings and embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the invention.

[0053] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0054] The term "comprising" and its variations as used herein are open-ended inclusions, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Definitions of other terms will be given in the description below.

[0055] It should be noted that the concepts of "first" and "second" mentioned in this invention are only used to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.

[0056] Although operations or steps are described in a specific order in the accompanying drawings in the embodiments of the present invention, this should not be construed as requiring these operations or steps to be performed in the specific order or serial order shown, or requiring all of the shown operations or steps to be performed to obtain the desired result. In the embodiments of the present invention, these operations or steps may be performed serially; they may be performed in parallel; or a portion of these operations or steps may be performed.

[0057] Furthermore, it is understood that the data involved in the technical solutions of this invention (including but not limited to the data itself, the acquisition or use of the data) shall comply with the requirements of relevant laws, regulations and related provisions. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains, and all parameters or indicators in the formulas involved in this invention are normalized values ​​that have eliminated the influence of dimensions.

[0058] The following will provide a detailed description of a method, system, and device for monitoring road subsidence defects provided by an embodiment of the present invention, with reference to the accompanying drawings.

[0059] Figure 1 This diagram illustrates the basic flow chart of a method for monitoring road subsidence defects according to an embodiment of the present invention. Figure 1 As shown, the method specifically includes the following steps:

[0060] Step S100: Collect ultrasonic echo signals from the target area on the road surface.

[0061] An ultrasonic probe is used to scan the target area of ​​the road surface, acquiring a series of one-dimensional ultrasonic echo signals that vary over time. These ultrasonic echo signals are recorded as the original signals. In this embodiment of the invention, to facilitate subsequent identification of the ultrasonic echo signal and thus accurately identify subsidence defects in the target area of ​​the road surface, the original signal is... Preprocessing is performed on the original signal. Bandpass filtering is performed to remove frequency noise irrelevant to the detection, resulting in a filtered ultrasonic echo signal. Baseline correction is then applied to the filtered ultrasonic echo signal to eliminate DC bias or low-frequency drift, thus obtaining the preprocessed final ultrasonic echo signal. Due to the original signal The preprocessing process is existing technology and will not be described in detail here.

[0062] Step S200: Divide the frequency band of the ultrasonic echo signal in the frequency domain into several sub-segments, analyze the spectral morphology characteristics of the echo signal based on the energy distribution in the sub-segments, and determine the scattering properties of the cavity subsidence in the target area of ​​the road surface.

[0063] Different types of pavement defects exhibit varying frequency characteristics in their response to incident ultrasonic waves due to differences in their geometry and physical properties. For example, planar defects such as cracks or delamination tend to produce broadband, transient specular reflections, while bulk, irregular defects such as cavities, which are precursors to subsidence, trigger more complex scattering phenomena. Their energy is mainly distributed in specific mid-to-low frequency bands, causing a leftward shift in the spectral morphology of the echo signal. Therefore, by finely dividing the signal across the entire frequency band and analyzing the energy distribution within the resulting sub-segments, these subtle differences in frequency response can be captured. This allows for the analysis of the spectral morphology of the echo signal, ultimately determining the scattering characteristics of cavities and subsidence in the target pavement area, thus facilitating the differentiation of different types of pavement defects.

[0064] Compared to traditional wavelet transform, wavelet packet transform (WPT) can analyze high-frequency signal details with greater precision and is suitable for processing complex signals such as ultrasonic echoes. Therefore, in this embodiment of the invention, the wavelet packet transform algorithm is used to process the preprocessed ultrasonic echo signal. Frequency band in the frequency domain Wavelet packet changes in layers will affect the ultrasonic echo signal. The frequency band is divided into Each sub-band is of equal width, and for each sub-band, also called a frequency band node, its corresponding decomposition coefficients are obtained.

[0065] Furthermore, regarding the ultrasonic echo signal The energy distribution in each segment is analyzed, such as which frequency components the signal energy is mainly concentrated on, and then the spectral morphology of the echo signal is analyzed to determine the scattering of cavities and subsidence in the target area of ​​the road surface, thus providing a strong basis for subsequent feature analysis and pattern recognition (such as identifying subsidence defects).

[0066] In this embodiment of the invention, step S200 above, based on the energy distribution in the sub-segment, analyzes the spectral morphology characteristics of the echo signal to determine the scattering properties of the cavity subsidence in the target area of ​​the road surface, including:

[0067] Step S201: Obtain several decomposition coefficients corresponding to each sub-segment when the frequency band of the ultrasonic echo signal is divided into several sub-segments in the frequency domain.

[0068] In this embodiment of the invention, the preprocessed ultrasonic echo signal is obtained using a wavelet packet transform algorithm. When a frequency band in the frequency domain is divided into several sub-segments, the decomposition coefficients are obtained for each sub-segment. The decomposition coefficients characterize the intensity of energy events within the frequency band corresponding to the sub-segment.

[0069] Step S202: Based on the aforementioned decomposition coefficients, determine the energy characteristic value of each sub-segment.

[0070] In this embodiment of the invention, for any first... The first sub-segment is calculated based on the decomposition coefficients. Energy characteristic value of each sub-segment ,in, Indicates the first The number of all decomposition coefficients corresponding to each sub-segment; Indicates the first The first sub-segment corresponds to the first Each decomposition coefficient.

[0071] Step S203: Based on the energy characteristic values ​​and center frequencies of all sub-segments, determine the spectral energy offset factor of the target area of ​​the road surface.

[0072] Considering the echo generated by a smooth interface (such as a healthy interlayer interface or an ideal horizontal crack front), its spectral morphology should be similar to that of the incident wave, showing good symmetry. However, the echo generated by scattering from a cavity sinkhole will cause significant spectral distortion due to multiple scattering and traveling scattering within it, especially the energy shift to the low-frequency region, resulting in a significant asymmetry in the spectral morphology.

[0073] Therefore, in this embodiment of the invention, the center frequency of each segment is obtained based on the ultrasonic sampling rate and the number of decomposition layers of the WPT algorithm. Since the specific process for obtaining the center frequency of each segment is prior art, it will not be described in detail here.

[0074] When ultrasonic waves pass through areas indicative of subsidence (such as cavities or loose areas), these irregular, air-filled regions act as "high-attenuation" and "strong-scattering" media for the waves. In these media, the high-frequency components attenuate much faster than the low-frequency components. Therefore, the echo signal passing through these areas suffers significant energy loss in its high-frequency components, while retaining relatively more energy in its low-frequency components. The "center of gravity" of the entire spectrum inevitably shifts towards the low-frequency end. Therefore, based on the energy characteristic values ​​and center frequencies of all sub-segments, a spectral energy shift factor for the target area of ​​the road surface is determined.

[0075] In this embodiment of the invention, step S203, determining the spectral energy shift factor of the target area of ​​the road surface, includes:

[0076] First, the cumulative value of the product of the energy characteristic value and the center frequency of all segments is determined to obtain the first cumulative value.

[0077] Secondly, the cumulative value of the energy characteristic values ​​of all sub-segments is determined to obtain the second cumulative value.

[0078] Finally, the ratio of the first accumulated value to the second accumulated value is determined to obtain the spectral energy shift factor of the target area of ​​the road surface.

[0079] The expression for calculating the spectral energy shift factor of the target area of ​​the road surface is as follows:

[0080]

[0081] In the formula: This represents the spectral energy shift factor of the target area on the road surface. Indicates the first The center frequency of each sub-segment; This indicates the number of all segments of the ultrasonic echo signal in the target area of ​​the road surface. Indicates the first Energy characteristic values ​​of each sub-segment.

[0082] Step S204: Based on the difference between the center frequency of all sub-segments and the spectral energy offset factor, and in combination with the energy characteristic values ​​of all sub-segments, determine the cavitation and subsidence scattering properties of the target area of ​​the road surface.

[0083] The greater the leftward skewness of the spectral energy distribution in the target area of ​​the road surface, the more likely the target area traversed by the ultrasonic waves is to be a pre-subsidence region. Therefore, based on the differences between the center frequencies and spectral energy shift factors of all sub-segments, and combined with the energy characteristic values ​​of all sub-segments, the degree of leftward skewness of the spectral energy distribution is analyzed to determine the scattering properties of the cavity subsidence in the target area of ​​the road surface.

[0084] In this embodiment of the invention, step S204, determining the scattering properties of the cavity subsidence in the target area of ​​the road surface, includes:

[0085] First, determine the difference between the center frequency of each sub-segment and the spectral energy offset factor, and determine the frequency difference value.

[0086] Secondly, the cumulative value of the product of the energy characteristic values ​​of all sub-segments and the frequency difference values ​​is determined to obtain the third cumulative value.

[0087] Finally, based on the ratio of the third accumulated value to the second accumulated value, the scattering property of the cavity subsidence in the target area of ​​the road surface is determined.

[0088] The calculation expression for determining the scattering property of void subsidence in the target area of ​​the road surface is as follows:

[0089]

[0090] In the formula: This indicates the scattering properties of void subsidence in the target area of ​​the road surface; This represents the spectral energy shift factor of the target area on the road surface. Indicates the first The center frequency of each sub-segment; This indicates the number of all segments of the ultrasonic echo signal in the target area of ​​the road surface. Indicates the first Energy characteristic values ​​of each sub-segment; This represents an exponential function with the natural constant e as the base. Where, when the center frequency of each segment... The smaller the difference between the frequency difference and the frequency energy shift factor, the more severe the distortion and asymmetry of the frequency energy distribution of the ultrasonic echo signal in the target area of ​​the road surface. This corresponds to the scattering physical phenomenon of cavity subsidence, and the larger the value of the scattering property of cavity subsidence.

[0091] Step S300: Based on the fluctuation changes of the ultrasonic echo signal, analyze the effective duration of the signal and determine the temporal dispersion of the target area on the road surface.

[0092] Identifying subsidence defects solely based on the spectral energy distribution of ultrasonic echo signals from the target area of ​​the road surface can still lead to defect confusion. Furthermore, it's important to consider that, in addition to spectral characteristics, different defects also exhibit differences in their echo patterns in the temporal domain. For example, the echoes from planar cracks are short-duration and sharp; while the scattered echoes from cavities, due to their complex internal paths, have more dispersed energy over time, resulting in echo tailing and prolonged duration. Therefore, analyzing the effective duration of the ultrasonic echo signal based on its inherent fluctuations and determining the temporal dispersion of the target area of ​​the road surface, and combining the leftward skewness of the spectral energy distribution with its temporal dispersion, can significantly improve the specificity of identifying cavities in the target road surface area.

[0093] In this embodiment of the invention, step S300, which analyzes the effective duration of the signal and determines the temporal dispersion of the target area of ​​the road surface, includes:

[0094] Step S301: Determine the effective duration of the ultrasonic echo signal based on the changes in the envelope of the ultrasonic echo signal.

[0095] Due to the ultrasonic echo signal in the target area of ​​the road surface The ultrasonic echo signal is a high-frequency oscillating waveform with both positive and negative amplitudes, making direct energy analysis difficult. Therefore, its amplitude profile is extracted to obtain the envelope of the ultrasonic echo signal. In this embodiment of the invention, the Hilbert transform algorithm is used to obtain the ultrasonic echo signal of the target area on the road surface. envelope The envelope Ultrasonic echo signals capable of accurately depicting target areas on the road surface Distribution profile on the time axis.

[0096] Furthermore, based on the changes in the envelope of the ultrasonic echo signal, the effective duration of the ultrasonic echo signal is determined. This effective duration reflects the duration of the main body of the ultrasonic echo signal.

[0097] In this embodiment of the invention, step S301, determining the effective duration of the ultrasonic echo signal, includes:

[0098] First, based on the changes in the envelope, the peak value of the envelope is determined, and based on the peak value, the energy threshold is determined. Specifically, the envelope of the ultrasonic echo signal is acquired. The peak value (maximum peak value) is determined, and an empirical parameter is preset. , take empirical parameters With envelope The product of the peak values ​​is used as the energy threshold. This method determines the energy threshold. For strong echoes, the energy threshold can be increased accordingly; for weak echoes, the energy threshold will be decreased accordingly to ensure that the main part of the signal can always be captured.

[0099] Secondly, searching backwards from the starting point in time, the starting point is determined as the time point when the signal value on the envelope first rises from below the energy threshold to equal to or above the energy threshold. Specifically, the search begins from the starting point in time to find the envelope. The value first fell below the energy threshold Rise to or above the energy threshold The time point is taken as the starting time point and recorded as . .

[0100] Next, the search proceeds backward from the end of time to determine the point in time when the signal value on the envelope first rises from below the energy threshold to equal to or above the energy threshold, which is then used as the termination point. Specifically, the search proceeds backward from the end of time to find the envelope. The value first fell below the energy threshold Rise to or above the energy threshold The time point is taken as the end time point and recorded as . .

[0101] Finally, the duration between the start time point and the end time point is taken as the effective duration of the ultrasonic echo signal. Specifically, based on the start time point... and termination time point Determine the effective duration of the ultrasonic echo signal. .

[0102] Step S302: Based on the difference between the effective duration and the reference effective duration corresponding to the healthy road surface area, determine the temporal dispersion of the target road surface area.

[0103] In this embodiment of the invention, following the same method as described above for obtaining the effective duration of the target road surface area, the effective duration of ultrasonic echo signals from multiple healthy road surface areas is pre-acquired. The average of the acquired multiple effective durations is calculated to obtain the mean effective duration. This mean effective duration is used as the reference effective duration corresponding to the healthy road surface area. This reference effective duration represents the reference duration of ideal specular reflection. .

[0104] Furthermore, based on the effective duration of the ultrasonic echo signal Reference effective duration The difference between them is obtained by using the following formula to determine the temporal dispersion of the target area of ​​the road surface:

[0105]

[0106] In the formula: This indicates the temporal dispersion of the target area on the road surface; This represents an exponential function with base e. Where, when Close to or less than When the exponent term is greater than or close to 1, A value less than or close to zero indicates that the echo signal may be an ultrasonic echo signal from a healthy road surface area; only when... Significantly greater than If the tailing of the echo signal is severe, it indicates that the echo signal may be a scattering echo from a hole.

[0107] Step S400: Based on the cavity subsidence scattering and the time-domain dispersion, determine the cavity subsidence discrimination factor for the target area of ​​the road surface.

[0108] Combining the leftward skewness of the spectral energy distribution of the target pavement area with its temporal dispersion can greatly improve the specificity of identifying cavities in the target pavement area. Therefore, by integrating the scattering and temporal dispersion of cavities and subsidence, a cavities and subsidence discrimination factor for the target pavement area can be obtained.

[0109] In this embodiment of the invention, based on the scattering properties of void subsidence... and temporal diffusion Determine the discriminant factor for void subsidence in the target area of ​​the road surface. In the formula, This represents a linear normalization function used to normalize values ​​to the range [0,1]. The void subsidence discrimination factor is also included. The larger the value, the more severe the leftward deviation and echo tail of the echo signal, and the greater the possibility that the echo signal is a scattering echo from a cavity; therefore, this dual discrimination mechanism ensures that only signals that simultaneously meet the spectral and time-domain scattering characteristics will be identified as originating from a cavity subsidence.

[0110] At this point, the cavity and subsidence discrimination factor of the target area of ​​the road surface can be obtained.

[0111] Step S500: Based on the cavity and subsidence discrimination factor, determine whether there is subsidence damage in the target area of ​​the road surface.

[0112] Preset a threshold parameter If the cavity and subsidence discrimination factor of the target area of ​​the road surface is greater than or equal to the threshold parameter If the current target area of ​​the road surface is determined to have subsidence defects, that is, there are precursor defects such as cavities or loose structure related to subsidence, otherwise it is determined that the current target area of ​​the road surface does not have subsidence defects.

[0113] This invention uses wavelet packet transform to perform multi-resolution decomposition of ultrasonic echo signals, which precisely captures the subtle differences in frequency response of different diseases. Combined with the left skewness of the spectrum and time-domain feature analysis, it fundamentally decouples the characteristics of subsidence diseases from complex mixed echo signals, making the disease diagnosis more accurate and reliable, and achieving precise identification of precursor diseases of subsidence.

[0114] Based on the same inventive concept, embodiments of the present invention also provide a monitoring device for road subsidence defects, such as... Figure 2 As shown, the device includes:

[0115] The ultrasonic signal acquisition module is used to collect ultrasonic echo signals from the target area of ​​the road surface.

[0116] The scattering analysis module is used to divide the frequency band of the ultrasonic echo signal in the frequency domain into several sub-segments, analyze the spectral morphology characteristics of the echo signal based on the energy distribution in the sub-segments, and determine the scattering properties of the cavity subsidence in the target area of ​​the road surface.

[0117] The dispersion analysis module is used to analyze the effective duration of the signal based on the fluctuation changes of the ultrasonic echo signal, and to determine the temporal dispersion of the target area of ​​the road surface.

[0118] The discrimination factor determination module is used to determine the cavity subsidence discrimination factor of the target area of ​​the road surface based on the cavity subsidence scattering and the time-domain dispersion.

[0119] The subsidence defect identification module is used to determine whether subsidence defects exist in the target area of ​​the road surface based on the cavity subsidence discrimination factor.

[0120] It should be noted that the device provided in the above embodiments is only an example of the division of the above functional modules. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the computer device can be divided into different functional modules to complete all or part of the functions described above.

[0121] Based on the same inventive concept, embodiments of the present invention also provide a monitoring system for road subsidence defects, such as... Figure 3 As shown, the system includes: a memory, a processor, and computer program code stored in the memory and running on the processor, wherein when the processor executes the computer program code, the system can perform any of the aforementioned methods for monitoring road subsidence.

[0122] In this embodiment of the invention, the system can be divided into functional modules according to the above method example. For example, each module can correspond to a separate functional module, or two or more functions can be integrated into one processing module. The integrated module can be implemented in hardware. It should be noted that the module division in this embodiment is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods.

[0123] Based on the same inventive concept, embodiments of the present invention also provide a computer program product, which includes: computer program code, which, when run on a computer, causes the computer to execute any of the aforementioned methods for monitoring road subsidence.

[0124] Based on the same inventive concept, embodiments of the present invention also provide a computer-readable storage medium storing computer program code, which, when executed on a computer, causes the computer to perform any of the aforementioned methods for monitoring road subsidence.

[0125] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for monitoring road subsidence defects, characterized in that, The method includes the following steps: Collect ultrasonic echo signals from the target area on the road surface; The frequency band of the ultrasonic echo signal in the frequency domain is divided into several sub-segments. Based on the energy distribution in the sub-segments, the spectral morphology characteristics of the echo signal are analyzed to determine the scattering properties of the cavity subsidence in the target area of ​​the road surface. Based on the fluctuations of the ultrasonic echo signal, the effective duration of the signal is analyzed to determine the temporal dispersion of the target area on the road surface. Based on the scattering properties of the cavity subsidence and the time-domain dispersion, a cavity subsidence discrimination factor for the target area of ​​the road surface is determined. Based on the aforementioned cavity and subsidence discrimination factor, it is determined whether the target area of ​​the road surface has subsidence damage; Based on the energy distribution in the sub-segments, the spectral morphology characteristics of the echo signal are analyzed to determine the scattering properties of cavitation subsidence in the target area of ​​the road surface, including: When the frequency band of the ultrasonic echo signal is divided into several sub-segments in the frequency domain, several decomposition coefficients corresponding to each sub-segment are obtained; Based on the aforementioned decomposition coefficients, the energy characteristic value of each sub-segment is determined; Based on the energy characteristic values ​​and center frequencies of all sub-segments, the spectral energy offset factor of the target area of ​​the road surface is determined; Based on the difference between the center frequency of all sub-segments and the spectral energy offset factor, and combined with the energy characteristic values ​​of all sub-segments, the scattering property of the cavity subsidence in the target area of ​​the road surface is determined. Analyze the effective duration of the signal to determine the temporal dispersion of the target area on the road surface, including: The effective duration of the ultrasonic echo signal is determined based on the changes in the envelope of the ultrasonic echo signal. The temporal dispersion of the target road surface area is determined based on the difference between the effective duration and the reference effective duration corresponding to the healthy road surface area.

2. The method for monitoring road subsidence according to claim 1, characterized in that, Determine the spectral energy shift factor for the target area of ​​the road surface, including: The first accumulated value is obtained by summing the products of the energy eigenvalues ​​and center frequencies of all segments. Determine the cumulative value of the energy characteristic values ​​of all sub-segments to obtain the second cumulative value; The ratio of the first accumulated value to the second accumulated value is determined to obtain the spectral energy shift factor of the target area of ​​the road surface.

3. The method for monitoring road subsidence according to claim 2, characterized in that, Determine the scattering properties of cavitation subsidence in the target area of ​​the road surface, including: Determine the difference between the center frequency of each sub-segment and the spectral energy offset factor, and determine the frequency difference value; The cumulative value of the product of the energy characteristic values ​​of all sub-segments and the frequency difference value is determined to obtain the third cumulative value; Based on the ratio of the third accumulated value to the second accumulated value, the scattering property of the cavity subsidence in the target area of ​​the road surface is determined.

4. The method for monitoring road subsidence according to claim 1, characterized in that, Determining the effective duration of the ultrasonic echo signal includes: Based on the changes in the envelope, the peak value of the envelope is determined, and based on the peak value, the energy threshold is determined. Searching backwards from the starting point of time, the time point at which the signal value on the envelope first rises from below the energy threshold to equal or above the energy threshold is determined as the starting time point; The search proceeds backward from the end of time to determine the point in time when the signal value on the envelope first rises from below the energy threshold to equal to or above the energy threshold, which is then taken as the termination point. The duration between the start time point and the end time point is taken as the effective duration of the ultrasonic echo signal.

5. The method for monitoring road subsidence according to claim 1, characterized in that, Before dividing the frequency band of the ultrasonic echo signal into several sub-segments in the frequency domain, the method further includes preprocessing the ultrasonic echo signal. The preprocessing process includes: The ultrasonic echo signal is bandpass filtered to obtain the filtered ultrasonic echo signal. Baseline correction is performed on the filtered ultrasonic echo signal to obtain the preprocessed ultrasonic echo signal.

6. The method for monitoring road subsidence according to claim 1, characterized in that, The frequency band of the ultrasonic echo signal in the frequency domain is divided into several sub-segments, including: The frequency band of the ultrasonic echo signal in the frequency domain is divided into several sub-bands of equal width using wavelet packet transform, and several decomposition coefficients corresponding to each sub-segment are obtained during the frequency band division process.

7. A monitoring device for road subsidence defects, characterized in that, The device includes: The ultrasonic signal acquisition module is used to collect ultrasonic echo signals from the target area of ​​the road surface. The scattering analysis module is used to divide the frequency band of the ultrasonic echo signal in the frequency domain into several sub-segments, analyze the spectral morphology characteristics of the echo signal based on the energy distribution in the sub-segments, and determine the scattering properties of the cavity subsidence in the target area of ​​the road surface. The dispersion analysis module is used to analyze the effective duration of the signal based on the fluctuation changes of the ultrasonic echo signal, and to determine the temporal dispersion of the target area of ​​the road surface. The discrimination factor determination module is used to determine the cavity subsidence discrimination factor of the target area of ​​the road surface based on the cavity subsidence scattering and the time-domain dispersion. The subsidence defect identification module is used to determine whether subsidence defects exist in the target area of ​​the road surface based on the cavity subsidence discrimination factor. Based on the energy distribution in the sub-segments, the spectral morphology characteristics of the echo signal are analyzed to determine the scattering properties of cavitation subsidence in the target area of ​​the road surface, including: When the frequency band of the ultrasonic echo signal is divided into several sub-segments in the frequency domain, several decomposition coefficients corresponding to each sub-segment are obtained; Based on the aforementioned decomposition coefficients, the energy characteristic value of each sub-segment is determined; Based on the energy characteristic values ​​and center frequencies of all sub-segments, the spectral energy offset factor of the target area of ​​the road surface is determined; Based on the difference between the center frequency of all sub-segments and the spectral energy offset factor, and combined with the energy characteristic values ​​of all sub-segments, the scattering property of the cavity subsidence in the target area of ​​the road surface is determined. Analyze the effective duration of the signal to determine the temporal dispersion of the target area on the road surface, including: The effective duration of the ultrasonic echo signal is determined based on the changes in the envelope of the ultrasonic echo signal. The temporal dispersion of the target road surface area is determined based on the difference between the effective duration and the reference effective duration corresponding to the healthy road surface area.

8. A monitoring system for road subsidence defects, characterized in that, The method includes a memory, a processor, and executable computer program code stored in the memory and executable on the processor. When the processor executes the computer program code, it performs a method for monitoring road subsidence as described in any one of claims 1 to 6.

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