Ancient building brick wall reinforcing method based on three-dimensional scanning and data analysis

Abstract

The invention discloses an ancient building brick wall reinforcing method based on three-dimensional scanning and data analysis, and particularly relates to the technical field of brick wall reinforcing. The internal structure of the brick wall is monitored through multi-frequency laser excitation, the interference degree of a heterogeneous repairing material on the integrity of a scanning signal is evaluated, and the influence of refraction and scattering of an optical signal on three-dimensional point cloud data is further analyzed. By constructing a local characteristic curve, the obstruction degree of the nonlinear optical effect on brick damage identification is evaluated. By analyzing the generalized spectral characteristics of the local characteristic curve and combining the refractive index of the repairing material and the energy conduction characteristics of the surface structure of the brick body, the error amplitude of the interface scattering anomaly on the measurement of the brick joint depth and the crack range is evaluated. And comprehensively analyzing the hindering degree of the nonlinear optical effect and the error amplitude of the interface scattering abnormity, evaluating the suitability of the brick body and the repairing material, and formulating a targeted reinforcing strategy to ensure the effectiveness and long-term stability of the reinforcing effect.

Description

Technical Field

[0001] The present invention relates to the technical field of brick wall reinforcement, and more specifically, to a method for reinforcing brick walls of ancient buildings based on three-dimensional scanning and data analysis. Background Art

[0002] In order to extend the service life of the brick walls of ancient buildings, engineers usually use heterogeneous repair materials to reinforce the damaged areas. Historically, heterogeneous repair materials have been used many times to irregularly embed into brick joints and depressions, resulting in significant differences in the optical properties of the repair materials and the original bricks.

[0003] When dealing with the reinforcement of ancient brick walls, existing methods are unable to effectively deal with the optical interference caused by heterogeneous repair materials, resulting in insufficient damage identification accuracy and a lack of pertinence and effectiveness in reinforcement strategies. As a result, it is difficult to formulate a scientific and efficient repair plan during the actual reinforcement process, affecting the overall effect of the protection of ancient brick walls.

[0004] In order to solve the above problems, a technical solution is now provided. Summary of the invention

[0005] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a method for reinforcing brick walls of ancient buildings based on three-dimensional scanning and data analysis to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions: A method for reinforcing brick walls of ancient buildings based on three-dimensional scanning and data analysis, comprising the following steps: By monitoring the reflection and absorption characteristics of the internal structure of the brick wall under multi-frequency laser excitation, the interference degree of the heterogeneous repair materials in the brick wall on the integrity of the scanning signal is evaluated; When the degree of interference of heterogeneous repair materials in brick walls on the integrity of scanning signals is low, the abnormal changes in light intensity distribution at the interface between the weathered layer of bricks and heterogeneous repair materials are analyzed to determine whether the refraction and scattering of light signals affect the resolution of 3D point cloud data. When the refraction and scattering of light signals affect the resolution of 3D point cloud data, a local characteristic curve of the difference between the spectral characteristics of heterogeneous repair materials and the background light response of the brick is constructed to evaluate the degree of obstruction of the nonlinear optical effect of heterogeneous repair materials on the identification of brick damage. By conducting a distributed analysis of the generalized spectral characteristics of the local characteristic curves and combining the refractive index of the heterogeneous repair material with the energy conduction characteristics of the brick surface structure, the error amplitude of the determination of the brick joint depth and crack range caused by the interface scattering anomaly caused by the heterogeneous repair material is evaluated. By comprehensively analyzing the degree of obstruction of brick damage identification caused by the nonlinear optical effect of heterogeneous repair materials and the error amplitude of brick joint depth and crack range measurement caused by interface scattering anomaly caused by heterogeneous repair materials, the compatibility of bricks and repair materials is evaluated, and targeted reinforcement strategies are formulated.

[0007] In a preferred embodiment, the degree of interference of heterogeneous repair materials in the brick wall on the integrity of the scanning signal is evaluated by monitoring the reflection and absorption characteristics of the internal structure of the brick wall under multi-frequency laser excitation, specifically: Select the appropriate laser frequency range and pulse power; Start the 3D scanning device to perform multi-frequency laser scanning on the brick wall and collect the reflection and absorption signal data matrix; The collected signal data is separated by frequency bands to extract the specific optical properties of the heterogeneous repair material and the background response characteristics of the brick wall; Based on the signal feature separation results, the nonlinear fitting algorithm is used, combined with the signal-to-noise ratio and error threshold, to evaluate the interference degree of heterogeneous repair materials on the integrity of the scanning signal. Combining the signal-to-noise ratio and the error threshold, the interference index is defined as follows: ;in, represents the interference index; represents the signal-to-noise ratio; represents the error threshold; Indicates the lower limit of the laser scanning frequency range; Indicates the upper limit of the laser scanning frequency range; Indicates the frequency The degree of optical interference under Preset the interference index threshold and compare the interference index with the interference index threshold: When the interference index is greater than or equal to the interference index threshold, it means that the interference degree of the heterogeneous repair material in the brick wall to the integrity of the scanning signal is high; When the interference index is less than the interference index threshold, it indicates that the interference degree of the heterogeneous repair material in the brick wall to the integrity of the scanning signal is low.

[0008] In a preferred embodiment, when the degree of interference of the heterogeneous repair material in the brick wall on the integrity of the scanning signal is low, by analyzing the abnormal change of the light intensity distribution at the interface between the weathered layer of the brick body and the heterogeneous repair material, it is determined whether the refraction and scattering of the light signal have an impact on the resolution of the three-dimensional point cloud data, specifically: According to the interface range between the heterogeneous repair material and the brick body, an area containing the light intensity distribution characteristics of the weathered layer and the heterogeneous repair material is selected; Collect light intensity data at different depths within the sampling area and construct a distribution model of light intensity varying with depth; Based on the light intensity distribution model, identify the abnormal change points of light intensity at the junction at the reflection and absorption peaks; The refraction angle and scattering distribution density of the interface light signal are calculated through the light intensity gradient of the abnormal change point; Combined with the refraction angle and scattering distribution, the impact of the abnormal light signal at the junction on the resolution of the three-dimensional point cloud data is evaluated.

[0009] In a preferred embodiment, the refraction angle and scattering distribution are combined to evaluate the influence of the abnormal light signal at the junction on the resolution of the three-dimensional point cloud data, specifically: Define the resolution loss index, the expression is ;in, is the resolution loss index; are the upper and lower limits of the depth range; For Depth The distribution density of light signal scattering at For Depth At , the sine value of the refraction angle of the light signal; A resolution loss index threshold is preset, and the resolution loss index is compared with the resolution loss index threshold: When the resolution loss index is greater than or equal to the resolution loss index threshold, it indicates that the refraction and scattering of the light signal have an impact on the resolution of the 3D point cloud data; When the resolution loss index is less than the resolution loss index threshold, it indicates that the refraction and scattering of the light signal have no effect on the resolution of the three-dimensional point cloud data.

[0010] In a preferred embodiment, when the refraction and scattering of the light signal affect the resolution of the three-dimensional point cloud data, a local characteristic curve of the difference between the spectral characteristics of the heterogeneous repair material and the background light response of the brick body is constructed to evaluate the degree of obstruction of the nonlinear optical effect of the heterogeneous repair material on the identification of brick body damage, specifically: Based on the interface between the weathered layer of the brick and the heterogeneous repair material, a high-resolution spectrometer is used to measure the reflectance spectrum of the heterogeneous repair material and the brick background. Perform frequency domain analysis on the reflected spectrum data to extract the spectral difference characteristics between the heterogeneous repair material and the brick background; Construct local characteristic curves based on spectral feature differences to analyze the nonlinear optical effects of material interfaces; Quantify the impact of nonlinear optical effects on damage identification accuracy and assess the degree of hindrance: define damage identification accuracy indicators : ;in, is the base of natural logarithms; Represents the nonlinear optical effect parameter of the repair material; Define the degree of obstruction based on the damage identification accuracy index : ; All sampling points The weighted average of the obstruction degree is used to obtain the obstruction index: ;in, is the obstacle index; is the total number of sampling points; The degree of obstruction.

[0011] In a preferred embodiment, by performing distributed analysis on the generalized spectral characteristics of the local characteristic curve, combined with the refractive index of the heterogeneous repair material and the energy conduction characteristics of the brick surface structure, the error amplitude of the crack range determination caused by the interface scattering anomaly caused by the heterogeneous repair material is evaluated, specifically: Extract generalized spectral features of local characteristic curves; The distributed analysis spectral characteristics are combined with the refractive index and energy conduction characteristics of the repair material; Evaluating the error margin of interface scattering anomalies on the determination of brick joint depth and crack extent: using a correlation model Predict the error caused by interface scattering anomalies : ;in, Indicates the depth The error range of the brick joint depth and crack range caused by the abnormal interface scattering; is the prediction output of the association model; Heterogeneous repair material The refractive index of Represents the surface structure of the brick The energy conductivity coefficient.

[0012] In a preferred embodiment, the degree of obstruction of brick damage identification caused by the nonlinear optical effect of heterogeneous repair materials and the error amplitude of the brick joint depth and crack range determination caused by the interface scattering anomaly caused by heterogeneous repair materials are comprehensively analyzed to evaluate the compatibility of bricks and repair materials, and formulate targeted reinforcement strategies, specifically: The obstruction index corresponding to the degree of obstruction of the nonlinear optical effect of the heterogeneous repair material on the identification of brick damage and the error amplitude corresponding to the error amplitude of the measurement of the brick joint depth and crack range caused by the interface scattering anomaly caused by the heterogeneous repair material are normalized, and the normalized obstruction index and error amplitude are calculated to obtain the adaptability index. The calculation formula is: ;in, represents the adaptability index; Indicates the depth The error range of the brick joint depth and crack range caused by the abnormal interface scattering; is the obstacle index; Preset the suitability index threshold and compare the suitability index with the suitability index threshold: When the compatibility index is greater than or equal to the compatibility index threshold, it means that the brick body and the repair material have a high compatibility, and there is no need to formulate a targeted reinforcement strategy; When the compatibility index is greater than or equal to the compatibility index threshold, it means that the compatibility between the brick body and the repair material is low, and a targeted reinforcement strategy needs to be formulated.

[0013] The technical effects and advantages of the ancient building brick wall reinforcement method based on three-dimensional scanning and data analysis of the present invention are as follows: 1. Through multi-frequency laser excitation and reflection absorption characteristic monitoring, the degree of interference of heterogeneous repair materials on scanning signals can be accurately evaluated, ensuring the accuracy of scanning data from the source. Secondly, by analyzing the abnormal changes in the light intensity distribution at the interface between the weathered layer of the brick and the repair material, the refraction and scattering effects of the light signal are judged, which effectively avoids the misjudgment of traditional data analysis algorithms when dealing with complex optical effects, thereby improving the resolution of three-dimensional point cloud data. Furthermore, by constructing local characteristic curves of the difference between spectral characteristics and brick background light response, the influence of nonlinear optical effects on brick damage identification can be quantified, ensuring the accuracy of damage assessment. In addition, combining the refractive index of heterogeneous repair materials with the energy conduction characteristics of the brick surface structure, the influence of interface scattering anomalies on the determination of crack depth and brick joint range is analyzed, providing more accurate crack analysis results.

[0014] 2. Through the evaluation of the adaptability index, we can accurately judge the compatibility of bricks and repair materials, formulate more scientific and precise reinforcement strategies, and effectively improve the effect and durability of the reinforcement of ancient building brick walls. It not only has important practical application value in the protection of ancient buildings, but also provides a new technical idea for the field of traditional building restoration. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of a method for reinforcing brick walls of ancient buildings based on three-dimensional scanning and data analysis according to the present invention. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] Example 1 Figure 1The present invention provides a method for reinforcing brick walls of ancient buildings based on three-dimensional scanning and data analysis, which comprises the following steps: By monitoring the reflection and absorption characteristics of the internal structure of the brick wall under multi-frequency laser excitation, the interference degree of the heterogeneous repair materials in the brick wall on the integrity of the scanning signal is evaluated; When the degree of interference of heterogeneous repair materials in brick walls on the integrity of scanning signals is low, the abnormal changes in light intensity distribution at the interface between the weathered layer of bricks and heterogeneous repair materials are analyzed to determine whether the refraction and scattering of light signals affect the resolution of 3D point cloud data. When the refraction and scattering of light signals affect the resolution of 3D point cloud data, a local characteristic curve of the difference between the spectral characteristics of heterogeneous repair materials and the background light response of the brick is constructed to evaluate the degree of obstruction of the nonlinear optical effect of heterogeneous repair materials on the identification of brick damage. By conducting a distributed analysis of the generalized spectral characteristics of the local characteristic curves and combining the refractive index of the heterogeneous repair material with the energy conduction characteristics of the brick surface structure, the error amplitude of the determination of the brick joint depth and crack range caused by the interface scattering anomaly caused by the heterogeneous repair material is evaluated. By comprehensively analyzing the degree of obstruction of brick damage identification caused by the nonlinear optical effect of heterogeneous repair materials and the error amplitude of brick joint depth and crack range measurement caused by interface scattering anomaly caused by heterogeneous repair materials, the compatibility of bricks and repair materials is evaluated, and targeted reinforcement strategies are formulated.

[0018] Specifically, by monitoring the reflection and absorption characteristics of the internal structure of the brick wall under multi-frequency laser excitation, the interference degree of the heterogeneous repair material in the brick wall on the integrity of the scanning signal is evaluated, including: Select an appropriate laser frequency range and pulse power: To ensure that the laser excitation adapts to the characteristics of the brick wall structure and the repair area, it is necessary to select appropriate laser parameters based on the optical response range of the brick wall material and the characteristics of the repair material.

[0019] Setting the laser frequency range and pulse frequency , satisfying the following conditions: laser frequency range The spectral absorption peaks of the brick and the repair material should be covered to ensure that the reflection and absorption characteristics can be captured in the entire frequency range; the laser pulse power Sufficient excitation intensity should be provided without damaging the weathered layer on the surface of the brick wall to avoid data distortion caused by thermal damage.

[0020] Start the 3D scanning device, perform multi-frequency laser scanning on the brick wall, and collect the reflection and absorption signal data matrix: Start the 3D scanning device, project the laser beam to the target area of ​​the brick wall, and obtain the reflection and absorption signals through multi-frequency scanning. Define the data collection matrix for ;in, is the laser frequency The reflected signal strength under , in watts per square meter; The laser frequency The absorption signal strength under , in watts per square meter; is the number of laser frequency points sampled, usually discrete frequency points within the multi-band coverage range.

[0021] The collected signal data is separated by frequency bands to extract the specific optical properties of the heterogeneous repair material and the background response characteristics of the brick wall. In order to distinguish the signal characteristics of the brick body and the heterogeneous repair material, the matrix Perform frequency band separation to extract the optical properties of specific materials. Assume that the spectral response range of the heterogeneous repair material is , the spectral response range of the brick wall background is , calculate the characteristic components separately: ;in, and represent the sum of reflection and absorption intensities of the repair material respectively; and Respectively represent the sum of reflection and absorption intensities of the brick background; and Respectively represent the frequency The reflected signal and absorbed signal intensities under the frequency Reflection and absorption response under represent the highest and lowest frequencies of the spectral response range of the heterogeneous repair material, respectively; Respectively represent the highest and lowest frequencies in the spectral response range of the background brick wall.

[0022] Based on the signal feature separation results, the nonlinear fitting algorithm is used, combined with the signal-to-noise ratio and error threshold, to evaluate the interference degree of heterogeneous repair materials on the integrity of the scanning signal: In order to quantitatively describe the interference degree of heterogeneous repair materials on the brick wall scanning signal, an interference function is constructed. for: ;in, Indicates the frequency The degree of optical interference under To avoid small positive values ​​with zero denominator; Indicates the frequency The intensity of the reflected signal of the heterogeneous repair material to the laser scanning; Indicates the frequency Below, the reflected signal intensity of the laser scan from the brick wall background; Indicates the frequency The absorption signal intensity of the heterogeneous repair material to the laser scanning; Indicates the frequency Below, the absorption signal intensity of the brick wall background to the laser scan.

[0023] Combining the signal-to-noise ratio and the error threshold, the interference index is defined as follows: ;in, represents the interference index; It represents the signal-to-noise ratio, which is calculated from the actual scanning data; Indicates the error threshold, which is set according to the scanning accuracy requirements or data tolerance standards; Indicates the lower limit of the laser scanning frequency range, in Hertz; Indicates the upper limit of the laser scanning frequency range, in Hertz.

[0024] Preset the interference index threshold and compare the interference index with the interference index threshold: When the interference index is greater than or equal to the interference index threshold, it means that the degree of interference of the heterogeneous repair materials in the brick wall on the integrity of the scanning signal is high, and it is necessary to start the signal correction and optimization process to reduce the impact of interference on the scanning results, including adjusting the laser scanning parameters, such as increasing the laser frequency or adjusting the pulse power, and optimizing the scanning angle to reduce reflection and scattering effects; When the interference index is less than the interference index threshold, it means that the interference degree of the heterogeneous repair material in the brick wall to the integrity of the scanning signal is low, and no additional intervention or correction is required, and the normal 3D scanning and data analysis process can continue; The interference index threshold is a fixed value determined based on the scanning accuracy requirements, noise tolerance, and actual application scenarios. It is usually preset based on experimental data and industry experience. By setting the interference index threshold, it can ensure that the signal integrity can be accurately judged under different interference conditions.

[0025] Specifically, when the degree of interference of heterogeneous repair materials in the brick wall on the integrity of the scanning signal is low, by analyzing the abnormal changes in the light intensity distribution at the interface between the weathered layer of the brick body and the heterogeneous repair materials, it is determined whether the refraction and scattering of the light signal have an impact on the resolution of the 3D point cloud data, including: According to the interface range of the heterogeneous repair material and the brick body, select the sampling area that includes the light intensity distribution characteristics of the weathered layer and the heterogeneous repair material: select the target area according to the interface range of the heterogeneous repair material and the brick body. The selection range must ensure that it includes both the coverage area of ​​the heterogeneous repair material and the weathered layer and its transition area. The specific selection process is as follows: The brick surface is an area in three-dimensional space The thickness of the weathering layer is The plane where the interface between the heterogeneous repair material and the brick body is located is The sampling area is defined as : ;in, is the three-dimensional space coordinate; Indicates the thickness of the weathered layer on the brick surface; Represents the additional sampling depth extending from the interface into the patch material.

[0026] The selection of sampling areas needs to balance the integrity of the coverage interface and the efficiency of data collection to ensure that the light intensity data can reflect the global distribution of the weathered layer and heterogeneous repair materials.

[0027] Collect light intensity data at different depths in the sampling area and build a distribution model of light intensity varying with depth: , collect the light intensity at different depths in layers, and build a distribution model of light intensity varying with depth. Set the depth range to , collect light intensity data : ; For sampling point The total light intensity at For sampling point The reflected light intensity component at ; For sampling point The absorbed light intensity component at .

[0028] Integrate light intensity data at different depths into a distribution model : ;in, For each depth The corresponding number of sampling points; For Depth The first The coordinates of the sampling points.

[0029] Based on the light intensity distribution model, identify the abnormal change points of the light intensity at the reflection and absorption peaks at the junction: extract the reflection peak and absorption peak of the light intensity from the light intensity distribution model, and detect the position and intensity of the abnormal change points. The detection function of abnormal light intensity change is defined as : ;in, For Depth The rate of change of light intensity at is the derivative of light intensity with depth.

[0030] The position of the abnormal light intensity change point meets the following conditions: ;in, It is the preset change rate threshold, which is used to determine whether the change is abnormal.

[0031] The identified abnormal change points correspond to the areas where the light intensity changes sharply, which are usually the concentrated points where the refraction or scattering effect of the light signal occurs.

[0032] The light intensity gradient at the abnormal change point is used to calculate the refraction angle and scattering distribution density of the interface light signal: After the abnormal change point of light intensity is detected, the refraction and scattering characteristics of the light signal at this point are further analyzed. The light intensity gradient at the abnormal change point is defined as : ;in, Depth in three-dimensional space The light intensity gradient at The light intensity is The rate of change of direction.

[0033] Calculate the refraction angle based on the light intensity gradient : ;in, For Depth At , the sine value of the refraction angle of the light signal; For Depth The refraction angle of the light signal at The tangential component of the light intensity gradient represents the change in light intensity in the direction parallel to the interface; Represents the modulus of the tangential component of the intensity gradient; is the light intensity gradient vector, which describes the rate and direction of change of light intensity in three-dimensional space; Represents the modulus of the light intensity gradient vector.

[0034] Scattering distribution density ;in, For Depth The distribution density of light signal scattering at For Depth The variance of the light intensity distribution at .

[0035] The greater the scattering distribution density, the deeper the light signal is. The more serious the scattering phenomenon at a certain depth, the more obvious the inhomogeneity of the light intensity distribution.

[0036] Combine the refraction angle and scattering distribution to quantify the impact of abnormal light signals on the resolution of 3D point clouds: The impact of abnormal light signals on the resolution of 3D point clouds is evaluated by the refraction angle and scattering distribution density. Define the resolution loss index, which is expressed as ;in, is the resolution loss index; are the upper and lower limits of the depth range; For Depth The distribution density of light signal scattering at For Depth At , the sine value of the refraction angle of the light signal.

[0037] A resolution loss index threshold is preset, and the resolution loss index is compared with the resolution loss index threshold: When the resolution loss index is greater than or equal to the resolution loss index threshold, it indicates that the refraction and scattering of the light signal affect the resolution of the 3D point cloud data, resulting in a decrease in the accuracy of the 3D point cloud data, and targeted interference compensation is required; When the resolution loss index is less than the resolution loss index threshold, it indicates that the refraction and scattering of the light signal have no effect on the resolution of the 3D point cloud data, and the resolution of the 3D point cloud data remains within an acceptable range, without the need for additional compensation or adjustment measures; The setting of the resolution loss index threshold is usually based on the requirements for point cloud data accuracy in actual application scenarios, combined with experimental measurement results and error tolerance.

[0038] Specifically, when the refraction and scattering of the light signal affect the resolution of the 3D point cloud data, a local characteristic curve of the difference between the spectral characteristics of the heterogeneous repair material and the background light response of the brick is constructed to evaluate the degree of obstruction of the nonlinear optical effect of the heterogeneous repair material on the identification of brick damage, including: Based on the interface between the weathered layer of the brick and the heterogeneous repair material, a high-resolution spectrometer is used to measure the reflectance spectrum of the heterogeneous repair material and the brick background: an appropriate high-resolution spectrometer is selected to ensure that the spectral resolution meets the experimental requirements. The equipment is calibrated, and the calibration parameters include wavelength calibration, light intensity calibration, etc. to ensure the accuracy of the measurement data. Reflectance spectrum data is collected at the interface according to the predetermined scanning path and points.

[0039] Perform frequency domain analysis on the reflected spectrum data to extract the spectral difference characteristics between the heterogeneous repair material and the brick background: Use Fourier transform to convert the spectral data in the time domain to the frequency domain to obtain frequency data ;in, For sampling point In frequency Analyze frequency domain data , extract the spectral response characteristics of heterogeneous repair materials and brick background at different frequencies: ;in, Indicates the frequency difference between heterogeneous repair material and brick background Spectral difference intensity under ; Indicates the frequency of heterogeneous repair materials Spectral response under Indicates the brick background at frequency The spectral response of .

[0040] The wavelength range that has a key impact on brick damage identification is screened out based on the spectral difference intensity , that is, the wavelength region where the spectrum differs significantly: ;in, is the preset spectral difference threshold; Indicates the selected critical wavelength range.

[0041] Construct local characteristic curves based on spectral feature differences to analyze the nonlinear optical effects of material interfaces: Based on the selected key wavelength range , plot the spectral difference intensity between the repair material and the brick background With wavelength The changing curve : ;in, The wavelength Corresponding frequency conversion relationship; Indicated in wavelength Next, sampling point Spectral difference characteristic curve.

[0042] By local characteristic curve Analyze the shape and change trend of the material to identify the nonlinear optical effects of the material interface: Curve morphology analysis: Detect whether the characteristic curve has obvious nonlinear bending, peak shift or waveform distortion, indicating that the optical signal is affected by nonlinear refraction or scattering at the material interface.

[0043] Change trend assessment: Analyze the change rate of the characteristic curve at different wavelengths to evaluate the intensity and distribution range of the nonlinear effect.

[0044] Use nonlinear regression model to analyze local characteristic curves Fitting to extract quantitative parameters of nonlinear optical effects : ;in, is the fitting function, which depends on the parameters ; Represents the nonlinear optical effect parameter of the repair material; is the fitting error.

[0045] The nonlinear optical effect parameter of the repair material is used as a quantitative indicator of the nonlinear optical effect to reflect the intensity of the nonlinear influence of the repair material on the optical signal: .parameter The larger it is, the more significant the impact of nonlinear optical effect on the optical signal is, and the greater the degree of hindrance to the identification of brick damage is.

[0046] Quantify the impact of nonlinear optical effects on damage identification accuracy and assess the degree of hindrance: define damage identification accuracy indicators , which is used to measure the change in the accuracy of the identification algorithm in the presence of nonlinear optical effects: ;in, is the base of natural logarithms; Represents the nonlinear optical effect parameters of the repair material.

[0047] Define the degree of obstruction based on the damage identification accuracy index : . All sampling points The weighted average of the obstruction degree is used to obtain the obstruction index: ;in, is the obstacle index; is the total number of sampling points; The degree of obstruction.

[0048] The larger the obstruction index, the more serious the obstruction of the nonlinear optical effect of the heterogeneous repair material to the identification of brick damage. Specifically, the nonlinear optical effect may cause abnormal changes in the absorption characteristics of the optical signal, thereby interfering with the propagation path of the optical signal during the three-dimensional scanning process. These effects will make it difficult to identify the damage characteristics of the brick body, thereby affecting the accuracy of damage identification. When the obstruction index is large, it means that there is a significant optical difference at the interface between the repair material and the brick body. This difference may cause serious distortion of the spectral signal and even make it difficult to extract the damage characteristics from the scanning data. This means that in the process of damage identification, there will be a larger error range, which will affect the final evaluation results.

[0049] Specifically, by performing distributed analysis on the generalized spectral characteristics of the local characteristic curves and combining the refractive index of the heterogeneous repair material with the energy conduction characteristics of the brick surface structure, the error amplitude of the crack range determination caused by the interface scattering anomaly caused by the heterogeneous repair material is evaluated, including: Extraction of generalized spectral features of local characteristic curves: The principal component analysis method is used to analyze the local characteristic curves. Perform dimensionality reduction processing to extract the main spectral feature vectors ;in, For the The principal component vectors reflect the main direction of spectral changes; the PCA algorithm is used to capture the main variability in spectral features and reduce data dimensions.

[0050] The extracted principal component vector To standardize: ;in, Represents the principal component vector The Euclidean norm of ; is the standardized principal component vector.

[0051] Distributed analysis of spectral characteristics combined with the refractive index and energy conduction characteristics of the repair material: Obtain the refractive index of heterogeneous repair materials at different wavelengths , indicating heterogeneous repair material In wavelength The refractive index under the condition of , the refractive index data can be obtained through experiments or literature.

[0052] Obtain the energy conductivity of the brick surface structure , indicating the surface structure of the brick In wavelength The energy conduction coefficient under the condition of , and the energy conduction data can be obtained through thermal analysis or literature.

[0053] Through multivariate regression analysis, the standardized principal component vector Refractive index and the energy conductivity Make associations and build association models : ;in, is a constant term; is the regression coefficient, which is used to describe the influence weight of the refractive index and energy conductivity coefficient on the correlation model; is the number of principal component vectors.

[0054] Evaluating the error margin of interface scattering anomalies on the determination of brick joint depth and crack extent: using a correlation model Predict the error caused by interface scattering anomalies : ;in, Indicates the depth The error range of the brick joint depth and crack range caused by the abnormal interface scattering; is the predicted output of the association model.

[0055] The larger the error amplitude, the more significant the interference of the interface scattering anomaly caused by the heterogeneous repair material on the crack range determination, and the greater the error of the measurement result. The larger error amplitude indicates that the nonlinear optical effect of the heterogeneous repair material, the refraction and scattering of the optical signal have caused a strong disturbance to the light propagation path, causing the originally clear crack interface signal to be distorted or scattered, thereby affecting the measurement result. This interference not only increases the error of the crack range measurement result, but also may cause misjudgment of the crack morphology and distribution.

[0056] Specifically, the compatibility of bricks and repair materials is evaluated, and targeted reinforcement strategies are formulated, including: The obstruction index corresponding to the degree of obstruction of the nonlinear optical effect of the heterogeneous repair material on the identification of brick damage and the error amplitude corresponding to the error amplitude of the measurement of the brick joint depth and the crack range caused by the interface scattering anomaly caused by the heterogeneous repair material are normalized. The normalized obstruction index and error amplitude are calculated to obtain the adaptability index, which is used to evaluate the adaptability of the brick body and the repair material and formulate targeted reinforcement strategies.

[0057] The calculation formula of the adaptability index is: ;in, represents the adaptability index; Indicates the depth The error range of the brick joint depth and crack range caused by the abnormal interface scattering; The obstacle index.

[0058] Preset the suitability index threshold and compare the suitability index with the suitability index threshold: When the compatibility index is greater than or equal to the compatibility index threshold, it means that the brick body and the repair material have a high compatibility, and there is no need to formulate a targeted reinforcement strategy; When the adaptability index is greater than or equal to the adaptability index threshold, it means that the adaptability between the brick body and the repair material is low, and it is necessary to formulate a targeted reinforcement strategy, adopt a more accurate interference compensation method, or choose a more suitable repair material.

[0059] The setting of the adaptability index threshold is obtained through the analysis of experimental data on the compatibility of a large number of repair materials and bricks, and is usually determined based on actual engineering cases and experimental research.

[0060] The above formulas are dimensionless and numerical calculations. The formula is a formula obtained by collecting a large amount of data and performing software simulation to obtain the most recent real situation. The preset parameters and thresholds in the formula are set by technicians in this field according to actual conditions. The parts not described in the present invention are applicable to the prior art.

Claims

1. A method for reinforcing brick walls of ancient buildings based on three-dimensional scanning and data analysis, characterized in that: The steps include: By monitoring the reflection and absorption characteristics of the internal structure of the brick wall under multi-frequency laser excitation, the interference degree of the heterogeneous repair materials in the brick wall on the integrity of the scanning signal is evaluated; When the degree of interference of heterogeneous repair materials in brick walls on the integrity of scanning signals is low, the abnormal changes in light intensity distribution at the interface between the weathered layer of bricks and heterogeneous repair materials are analyzed to determine whether the refraction and scattering of light signals affect the resolution of 3D point cloud data. When the refraction and scattering of light signals affect the resolution of 3D point cloud data, a local characteristic curve of the difference between the spectral characteristics of heterogeneous repair materials and the background light response of the brick is constructed to evaluate the degree of obstruction of the nonlinear optical effect of heterogeneous repair materials on the identification of brick damage. By conducting a distributed analysis of the generalized spectral characteristics of the local characteristic curves and combining the refractive index of the heterogeneous repair material with the energy conduction characteristics of the brick surface structure, the error amplitude of the determination of the brick joint depth and crack range caused by the interface scattering anomaly caused by the heterogeneous repair material is evaluated. By comprehensively analyzing the degree of obstruction of brick damage identification caused by the nonlinear optical effect of heterogeneous repair materials and the error amplitude of brick joint depth and crack range measurement caused by interface scattering anomaly caused by heterogeneous repair materials, the compatibility of bricks and repair materials is evaluated, and targeted reinforcement strategies are formulated.

2. The ancient building brick wall reinforcement method based on three-dimensional scanning and data analysis according to claim 1 is characterized in that: By monitoring the reflection and absorption characteristics of the internal structure of the brick wall under multi-frequency laser excitation, the interference degree of the heterogeneous repair material in the brick wall on the integrity of the scanning signal is evaluated, specifically: Select the appropriate laser frequency range and pulse power; Start the 3D scanning device to perform multi-frequency laser scanning on the brick wall and collect the reflection and absorption signal data matrix; The collected signal data is separated by frequency bands to extract the specific optical properties of the heterogeneous repair material and the background response characteristics of the brick wall; Based on the signal feature separation results, the nonlinear fitting algorithm is used, combined with the signal-to-noise ratio and error threshold, to evaluate the interference degree of heterogeneous repair materials on the integrity of the scanning signal. Combining the signal-to-noise ratio and the error threshold, the interference index is defined as follows: ;in, represents the interference index; represents the signal-to-noise ratio; represents the error threshold; Indicates the lower limit of the laser scanning frequency range; Indicates the upper limit of the laser scanning frequency range; Indicates the frequency The degree of optical interference under Preset the interference index threshold and compare the interference index with the interference index threshold: When the interference index is greater than or equal to the interference index threshold, it means that the interference degree of the heterogeneous repair material in the brick wall to the integrity of the scanning signal is high; When the interference index is less than the interference index threshold, it indicates that the interference degree of the heterogeneous repair material in the brick wall to the integrity of the scanning signal is low.

3. The ancient building brick wall reinforcement method based on three-dimensional scanning and data analysis according to claim 2 is characterized in that: When the degree of interference of heterogeneous repair materials in brick walls on the integrity of scanning signals is low, the abnormal changes in light intensity distribution at the interface between the weathered layer of the brick body and the heterogeneous repair materials are analyzed to determine whether the refraction and scattering of light signals affect the resolution of 3D point cloud data. Specifically: According to the interface range between the heterogeneous repair material and the brick body, an area containing the light intensity distribution characteristics of the weathered layer and the heterogeneous repair material is selected; Collect light intensity data at different depths within the sampling area and construct a distribution model of light intensity varying with depth; Based on the light intensity distribution model, identify the abnormal change points of light intensity at the reflection and absorption peaks at the junction; The refraction angle and scattering distribution density of the interface light signal are calculated through the light intensity gradient of the abnormal change point; Combined with the refraction angle and scattering distribution, the impact of the abnormal light signal at the junction on the resolution of the three-dimensional point cloud data is evaluated.

4. The method for reinforcing brick walls of ancient buildings based on three-dimensional scanning and data analysis according to claim 3 is characterized in that: Combined with the refraction angle and scattering distribution, the influence of the abnormal light signal at the junction on the resolution of the 3D point cloud data is evaluated, specifically: Define the resolution loss index, the expression is ;in, is the resolution loss index; are the upper and lower limits of the depth range; For Depth The distribution density of light signal scattering at For Depth At , the sine value of the refraction angle of the light signal; A resolution loss index threshold is preset, and the resolution loss index is compared with the resolution loss index threshold: When the resolution loss index is greater than or equal to the resolution loss index threshold, it indicates that the refraction and scattering of the light signal have an impact on the resolution of the 3D point cloud data; When the resolution loss index is less than the resolution loss index threshold, it indicates that the refraction and scattering of the light signal have no effect on the resolution of the three-dimensional point cloud data.

5. The method for reinforcing brick walls of ancient buildings based on three-dimensional scanning and data analysis according to claim 4 is characterized in that: When the refraction and scattering of light signals affect the resolution of 3D point cloud data, a local characteristic curve of the difference between the spectral characteristics of heterogeneous repair materials and the background light response of the brick is constructed to evaluate the degree of obstruction of the nonlinear optical effect of heterogeneous repair materials on the identification of brick damage, specifically: Based on the interface between the weathered layer of the brick and the heterogeneous repair material, a high-resolution spectrometer is used to measure the reflectance spectrum of the heterogeneous repair material and the brick background. Perform frequency domain analysis on the reflected spectrum data to extract the spectral difference characteristics between the heterogeneous repair material and the brick background; Construct local characteristic curves based on spectral feature differences to analyze the nonlinear optical effects of material interfaces; Quantify the impact of nonlinear optical effects on damage identification accuracy and assess the degree of hindrance: define damage identification accuracy indicators : ;in, is the base of natural logarithms; Represents the nonlinear optical effect parameter of the repair material; Define the degree of obstruction based on the damage identification accuracy index : ; Set all sampling points The weighted average of the obstruction degree is used to obtain the obstruction index: ;in, is the obstacle index; is the total number of sampling points; The degree of obstruction.

6. The method for reinforcing brick walls of ancient buildings based on three-dimensional scanning and data analysis according to claim 5 is characterized in that: By performing distributed analysis on the generalized spectral characteristics of the local characteristic curves and combining the refractive index of the heterogeneous repair material with the energy conduction characteristics of the brick surface structure, the error amplitude of the crack range determination caused by the interface scattering anomaly caused by the heterogeneous repair material is evaluated, specifically: Extract generalized spectral features of local characteristic curves; The distributed analysis spectral characteristics are combined with the refractive index and energy conduction characteristics of the repair material; Evaluating the error margin of interface scattering anomalies on the determination of brick joint depth and crack extent: using a correlation model Predict the error caused by interface scattering anomalies : ;in, Indicates the depth The error range of the brick joint depth and crack range caused by the abnormal interface scattering; is the prediction output of the association model; Heterogeneous repair material The refractive index of Represents the surface structure of the brick The energy conductivity coefficient.

7. The ancient building brick wall reinforcement method based on three-dimensional scanning and data analysis according to claim 6 is characterized in that: Through a comprehensive analysis of the degree of obstruction of brick damage identification caused by the nonlinear optical effect of heterogeneous repair materials and the error amplitude of the determination of brick joint depth and crack range caused by the interface scattering anomaly caused by heterogeneous repair materials, the compatibility of bricks and repair materials is evaluated, and targeted reinforcement strategies are formulated, specifically: The obstruction index corresponding to the degree of obstruction of the nonlinear optical effect of the heterogeneous repair material on the identification of brick damage and the error amplitude corresponding to the error amplitude of the measurement of the brick joint depth and crack range caused by the interface scattering anomaly caused by the heterogeneous repair material are normalized, and the normalized obstruction index and error amplitude are calculated to obtain the adaptability index. The calculation formula is: ;in, represents the adaptability index; Indicates the depth The error range of the brick joint depth and crack range caused by the abnormal interface scattering; is the obstacle index; Preset the suitability index threshold and compare the suitability index with the suitability index threshold: When the compatibility index is greater than or equal to the compatibility index threshold, it means that the brick body and the repair material have a high compatibility, and there is no need to formulate a targeted reinforcement strategy; When the compatibility index is greater than or equal to the compatibility index threshold, it means that the compatibility between the brick body and the repair material is low, and a targeted reinforcement strategy needs to be formulated.

Images