Stone cultural relic surface deterioration degree evaluation method based on thermal infrared imaging

Abstract

The invention relates to the technical field of stone cultural relic deterioration degree evaluation, and discloses a stone cultural relic surface deterioration degree evaluation method based on thermal infrared imaging, which comprises the following steps: S10, preparation for detection: determining a to-be-detected stone cultural relic area, carrying out detailed marking to ensure that the detection area is accurate, pasting a ruler at the edge of the detection area, and carrying out thermal infrared imaging on the surface of the stone cultural relic; preparing thermal excitation equipment as a reference basis for subsequent image processing and data analysis, and applying thermal excitation to the target area to change the surface temperature distribution of the cultural relics so as to facilitate thermal infrared imaging to capture differences; and S20, thermal infrared imaging: transporting a thermal infrared imaging instrument to a detection site to ensure that the instrument is in a stable state. According to the thermal infrared imaging-based stone cultural relic surface deterioration degree evaluation method, non-contact and high-precision disease detection and quantitative evaluation are realized, and a scientific basis is provided for protection and repair of stone cultural relics.

Description

Technical Field

[0001] The invention relates to the technical field of stone cultural relic deterioration degree evaluation, and in particular to a method for evaluating the deterioration degree of the surface of a stone cultural relic based on thermal infrared imaging. Background Art

[0002] Existing stone cultural relics have generally suffered varying degrees of erosion and damage, which are manifested in the spread of cracks, the intensification of hollowing phenomena, and the gradual peeling of surface materials. These diseases not only seriously threaten the structural safety of cultural relics, but also profoundly affect the complete display of their historical value and artistic style. Traditionally, the investigation of rock cultural relics is mostly carried out by direct contact measurement, that is, surveyors need to directly observe and record the surface of the cultural relics, and may use tools to measure dimensions or collect samples. However, this method has exposed many limitations in practice. On the one hand, direct contact may cause contamination of the surface of the cultural relics, such as The chemical reagents used in the survey process and the grease or stains on the measuring tools may remain on the cultural relics, and long-term accumulation will cause irreversible damage to them. At the same time, physical contact may also aggravate the wear and tear and peeling of cultural relics, especially for those areas that are already fragile or already damaged. On the other hand, direct contact surveys in steep and rugged areas not only greatly increase the difficulty, but also significantly increase the risk factor. Surveyors need to overcome the challenges of natural conditions such as complex terrain and changeable climate, and perform high-altitude operations or climbing, which undoubtedly increases the risk of operations and places higher demands on the professional skills and safety protection measures of surveyors.

[0003] Infrared thermal imaging nondestructive testing technology, as an emerging digital testing method, has achieved remarkable development in recent years. Its convenience and high precision have attracted much attention. This technology is rooted in the principle of infrared radiation. By capturing and analyzing the infrared radiation emitted from the surface of an object, it deeply explores the energy flow inside the object, and then intuitively displays the thermal distribution characteristics of the object in the form of a thermal image, providing strong technical support for the detection of internal defects. However, although infrared thermal imaging technology has shown certain application potential in the field of protection of stone cultural relics, especially in the detection of cracks, its application scope and depth are still insufficient. Specifically, this technology is currently used in hollowing and detaching stone cultural relics. It is rarely used in the detection of more complex and hidden diseases such as falling off, which also pose a major threat to the structural safety and appearance preservation of cultural relics. Therefore, broadening the application scope of infrared thermal imaging technology in the detection of stone cultural relics diseases is a technical problem that needs to be solved urgently. In addition, existing research focuses on using infrared technology to measure the size of diseases, while there is a lack of in-depth and systematic research on how to use infrared thermal imaging to make a more accurate and quantitative evaluation of the degree of surface diseases of cultural relics. As a result, in actual applications, infrared thermal imaging technology can often only provide qualitative analysis of diseases, but cannot provide quantitative indicators of the severity of diseases, thereby limiting its precise application and effect evaluation in cultural relic protection work. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] The purpose of the present invention is to realize non-contact, high-precision disease detection and quantitative evaluation, and to provide a scientific basis for the protection and restoration of stone cultural relics. A method for evaluating the degree of deterioration of the surface of stone cultural relics based on thermal infrared imaging is proposed.

[0006] (II) Technical solution

[0007] The technical solution of the present invention to solve the above technical problems is as follows:

[0008] A method for evaluating the degree of deterioration of the surface of stone cultural relics based on thermal infrared imaging comprises the following steps:

[0009] S10, test preparation, determine the area of ​​stone cultural relics to be tested, and make detailed marks to ensure that the test area is accurate, paste a ruler on the edge of the test area as a reference for subsequent image processing and data analysis, prepare thermal excitation equipment, and apply thermal excitation to the target area to change the surface temperature distribution of the cultural relics, so that thermal infrared imaging can capture the difference;

[0010] S20, thermal infrared imaging: transport the thermal infrared imaging instrument to the inspection site, ensure that the instrument is in a stable state, adjust the focus and camera mode of the thermal infrared imaging instrument to ensure that the thermal image of the target area can be clearly captured, perform thermal infrared imaging of the target area, and record and save the imaging results;

[0011] S30, image and data processing, import the optical image into Image J software to observe the basic morphology and details of the surface of the cultural relic. In Image J, use the Set scale function to convert the ratio of pixels to length according to the ruler, use the Polygon function to outline and calculate the area of ​​the surface detachment on the image, record the relevant data, determine and record whether there are cracks on the surface of the cultural relic. If there are, use the Straight function to measure the length and width of each crack, import the thermal infrared image into InfRec Analyzer NS9500 Standard software, and export the temperature information data of the target area;

[0012] S40, grid division and data attribution, reasonably dividing the grid according to the size and shape of the detection area, and numbering each grid unit, and attributing the previously recorded data such as the detachment area, crack length, width and temperature information to the corresponding grid unit according to the grid division result;

[0013] S50, data normalization and weight calculation, clarify which indicators are positive indicators such as temperature uniformity, which are negative indicators such as shedding area and crack length, normalize the data to eliminate dimensional differences, facilitate subsequent calculations, use the entropy method to calculate the objective weight of each indicator, ensure that the actual situation reflected by the data is fairly reflected in the evaluation system, combine the AHP hierarchical analysis method to determine the subjective weight of each indicator, comprehensively consider expert opinions and actual conditions, combine the objective weight with the subjective weight, and calculate the comprehensive weight of each indicator;

[0014] S60. Evaluation system construction and scoring. According to the characteristics of surface deterioration of stone cultural relics and actual needs, an evaluation system and corresponding matrix are constructed. The comprehensive weight is used to perform weighted summation on the indicators in each grid unit to obtain the score of the grid unit. The score of each grid unit is visualized through coordinate mapping to form an intuitive evaluation diagram. The average score of the entire detection area is calculated, and the degree of deterioration of the stone cultural relic area is determined according to preset grading standards such as excellent, good, medium, and poor.

[0015] Based on the above technical solution, the present invention can also be improved as follows.

[0016] Furthermore, the step S10 specifically includes the following steps:

[0017] S101. Determine the area to be tested, carefully survey the stone cultural relics, and identify the specific area to be tested. This is usually based on the history, preservation status, and possible signs of deterioration such as cracks and shedding of the cultural relics. Use marking tools such as chalk, markers or labels to clearly mark the boundaries of the test area on the surface of the cultural relics to ensure that subsequent testing work can be concentrated in this area;

[0018] S102, sticking the ruler, selecting a suitable position to stick the ruler on the edge of the detection area. The ruler should be firmly stuck and not easy to fall off or shift, and its scale should be clearly visible. Ensure that the direction of the ruler is consistent with the main dimensions of the detection area, such as length and width, so that it can be used as a reference benchmark in subsequent image processing and data analysis. Record the sticking position and scale information of the ruler for accurate reference in subsequent steps;

[0019] S103, prepare thermal excitation equipment, select appropriate thermal excitation equipment according to the type of cultural relics and detection requirements, the thermal excitation equipment can be a heat source generator, a heating lamp, an infrared radiator, etc., check the working status of the thermal excitation equipment to ensure that it can work normally and generate stable heat output, and adjust the layout and power of the thermal excitation equipment according to the size and shape of the detection area to ensure that thermal excitation can be evenly applied to the target area;

[0020] S104. Apply thermal excitation. Under the premise of ensuring the safety of the cultural relics and not affecting their original state, apply thermal excitation to the inspection area. The thermal excitation can be applied in the form of continuous heating or intermittent heating, depending on the material of the cultural relic and the inspection requirements. Observe the changes in the surface temperature distribution of the cultural relic to ensure that the thermal excitation effect reaches the expected effect. A thermal imager or other temperature measurement tools can be used for preliminary inspection to record the time of applying the thermal excitation, the temperature range and the temperature changes on the surface of the cultural relic to provide a reference for subsequent thermal infrared imaging and data analysis.

[0021] Furthermore, the step S20 specifically includes the following steps:

[0022] S201. Transport and place the instrument. Safely transport the thermal infrared imaging instrument and its accessories to the testing site. Select a stable, unobstructed and well-ventilated location to place the instrument to ensure that the instrument will not be disturbed by the external environment during the testing process.

[0023] S202, Instrument inspection and preparation: Check whether the appearance of the instrument is intact, without damage or loose parts, confirm that the instrument battery or external power supply is connected and has sufficient power, start the instrument according to the instrument manual, and wait for the instrument to enter a stable state;

[0024] S203, adjust the focus and camera mode, use the focus adjustment knob or button on the instrument to adjust the focus according to the actual distance of the target area to ensure that the image is clear, enter the instrument's setting menu, select the appropriate camera mode, including temperature range, color mapping, etc., so as to clearly display the thermal difference of the target area, preview the adjusted image, and ensure that there is no blur, distortion or overexposure;

[0025] S204, aiming at the target area and imaging, aiming the lens of the instrument at the target area of ​​the stone cultural relic to be detected, ensuring that the entire area is within the field of view, paying attention to avoid interference from direct sunlight or other heat sources, keeping the detection environment relatively stable, pressing the imaging button or triggering the imaging function, starting thermal infrared imaging of the target area, observing the real-time image on the instrument display screen, and ensuring that the imaging process proceeds smoothly;

[0026] S205. Record and save the imaging results. After the imaging is completed, check and record the imaging results on the instrument immediately. Pay attention to check whether the image is clear and complete, and mark any abnormal or suspected damaged areas. Use the instrument's built-in storage function or an external storage device such as an SD card, USB flash drive, etc. to save the imaging results. Make sure the file name and storage path are clear and unambiguous to facilitate subsequent search and use.

[0027] Furthermore, the specific operation steps in step S30 include:

[0028] S301, importing optical images into Image J, opening Image J software, selecting the "Open..." option in the "File" menu, browsing and importing the required optical image files, and confirming that the images are correctly loaded and displayed in the main window of Image J;

[0029] S302, observe the surface morphology of the cultural relic, use the zoom and pan tools of Image J to carefully observe the basic morphology and details of the surface of the cultural relic, and adjust the brightness and contrast of the image to observe the surface features more clearly;

[0030] S303, set the ratio of pixels to length. In Image J, find the "SetScale..." function under the "Analyze" menu. According to the ruler in the image, such as a reference object with a known length, enter the actual length value and set the corresponding unit, such as millimeters or centimeters. Click "OK" to confirm. At this time, Image J will automatically convert the ratio of pixels to length.

[0031] S304, outline and calculate the area of ​​the detached part, switch to the "Freehand Selections" or "PolygonSelections" tool depending on the Image J version, outline the detached part of the surface of the cultural relic on the image, and ensure that the outline accurately covers the entire detached area. Use the "Measure..." function under the "Analyze" menu to calculate and display the area of ​​the outlined area, and record the relevant data;

[0032] S305. Determine and record the cracks. Carefully observe the surface of the cultural relic to determine whether there are cracks. If there are cracks, use the "Straight Line Selection" tool or a similar tool to draw straight line segments on each crack to mark its position and direction. Use the measurement function of Image J to measure and record the length and width of each crack. It may be necessary to make precise measurements through visual estimation or with the help of other tools.

[0033] S306, importing the thermal infrared image into InfRec Analyzer NS9500 Standard, opening the InfRecAnalyzer NS9500 Standard software, selecting an appropriate file import option, and browsing and importing the thermal infrared image file generated in step S20;

[0034] S307. Export the target area temperature information data. In InfRec Analyzer NS9500 Standard, use the tools provided by the software to locate and select the target area. According to the functions and interface of the software, select the option to export the temperature information data, set the export file format, path and parameters to ensure that valid data containing the target area temperature information can be exported. Click "Export" or a similar button to complete the data export process and save the exported data file.

[0035] Furthermore, the step S40 specifically includes the following steps:

[0036] S401, determine the grid division scheme, design a reasonable grid division scheme according to the size, shape and detection requirements of the detection area, consider the size and shape of the grid (such as square, rectangle, hexagon, etc.) and the overlap or gap between the grids, ensure that the grid division can fully cover the detection area, and facilitate subsequent data processing and analysis;

[0037] S402, grid division and numbering, using drawing software such as AutoCAD, GIS software or hand-drawn sketches to draw a grid on the detection area according to the determined grid division scheme, assigning a unique number to each grid unit to ensure the continuity and easy identification of the numbering, and marking important reference points or boundaries on the grid map for subsequent data attribution and verification;

[0038] S403, sorting and classifying data, reviewing previously recorded data such as the shedding area, crack length, width, and temperature information, ensuring the accuracy and completeness of the data, and sorting and classifying the data according to the type and characteristics of the data, such as classifying the shedding area data into one category, the crack length and width data into another category, and the temperature information data into another category;

[0039] S404, data is assigned to grid units. According to the grid division result and the spatial location information of the data, the classified data is assigned to the corresponding grid unit. For each grid unit, its number and all relevant data belonging to the unit are recorded. Tools such as tables, databases or GIS systems can be used to store and manage these data for subsequent query and analysis;

[0040] S405. Verify the accuracy of data attribution. Verify the data attribution process to ensure that each data item is correctly attributed to the corresponding grid unit. Visualization tools such as GIS software can be used to display the results of grid division and data attribution to visually check the accuracy and consistency of the data.

[0041] S406. Record and save the results, record the grid division results, data attribution, and any problems or precautions found during the verification process, and save all relevant data files, charts and records for subsequent analysis and report writing.

[0042] Furthermore, the step S50 specifically includes the following steps:

[0043] S501. Clarify the positive and negative directions of the indicators and analyze the nature of the indicators: According to the direction of the impact of the evaluation indicators on cultural relics protection or evaluation targets, clarify which indicators are positive indicators such as temperature uniformity, the larger the value, the more beneficial it is to cultural relics protection, and which indicators are negative indicators such as detached area and crack length, the larger the value, the more serious the damage to the cultural relics, list all the indicators that need to be evaluated, and mark their positive and negative directions;

[0044] S502, data normalization processing, selecting an appropriate normalization method such as maximum-minimum normalization, Z-score normalization, etc. according to the characteristics and requirements of the data to eliminate the influence of different dimensions and magnitudes on data analysis, and converting all data according to the selected normalization method so that it falls into a unified numerical range such as [0,1];

[0045] The positive indicators are normalized:

[0046]

[0047] Negative indicator normalization:

[0048]

[0049] Where: is the jth index of the ith unit, i = 1, 2, 3, ... n; j = 1, 2, 3, ... m

[0050] S503, calculating the objective weight of the entropy method, organizing the normalized data into a decision matrix, wherein the rows represent the evaluation objects and the columns represent the evaluation indicators, calculating the information entropy of each evaluation indicator according to the definition and calculation formula of entropy, reflecting the discrete degree of its data distribution, and calculating the difference coefficient using the information entropy. The larger the difference coefficient, the higher the importance of the indicator in the evaluation system. Calculate the objective weight of the entropy method of each evaluation indicator according to the difference coefficient;

[0051] Use the following formula to calculate the weights of different indicators of the unit

[0052]

[0053] The entropy of the jth term is calculated using the following formula:

[0054]

[0055] The coefficient of variation for the jth term is calculated using the following formula:

[0056] d j =1-e j

[0057] Use the following formula to calculate the objective weight of each indicator:

[0058]

[0059] S504. Determine subjective weights by applying AHP. Divide evaluation objectives, evaluation indicators, and decision-making plans into hierarchical structures, invite experts to compare indicators in the same hierarchy, give scores based on their importance, construct a judgment matrix, and use mathematical methods to calculate the eigenvector and maximum eigenvalue of the judgment matrix. The eigenvector is the relative importance ranking of each indicator, i.e., the subjective weight. Perform consistency checks on the judgment matrix to ensure that the expert's scoring results are logically consistent.

[0060] The important coefficients of objective weight and subjective weight are calculated using the following formula:

[0061]

[0062]

[0063] S505, calculation of comprehensive weights, selecting appropriate comprehensive weight calculation methods such as simple average method, weighted average method, etc., combining the objective weights obtained by the entropy method and the subjective weights obtained by the AHP hierarchical analysis method, and calculating the comprehensive weights of each evaluation index according to the selected method to ensure that the actual situation reflected by the data is fairly reflected in the evaluation system;

[0064] The comprehensive weight is calculated using the following formula:

[0065]

[0066] S506. Verify and adjust the results. Verify the calculated comprehensive weight to ensure that it is consistent with the actual situation and has no obvious logical errors.

[0067] Furthermore, the step S60 specifically includes the following steps:

[0068] S601. Selection and definition of evaluation indicators. According to the characteristics of surface deterioration of stone cultural relics and actual needs, specific evaluation indicators should be selected and defined. These indicators should be able to fully reflect the deterioration of cultural relics, such as weathering degree, crack density, peeling area, stain type and distribution, microbial erosion degree, etc.

[0069] S602. Construct an evaluation system and weight matrix. Construct an evaluation system framework. Use appropriate methods such as AHP and Delphi method to determine the weight of each evaluation indicator and construct a weight matrix. The weight should reflect the importance and relative contribution of each indicator in the evaluation system.

[0070] S603, data collection and preprocessing, using professional equipment or tools to collect data for various indicators in each grid unit, and clean, convert and standardize the collected data to ensure the consistency and comparability of the data, laying the foundation for subsequent analysis;

[0071] S604, weighted summation to calculate grid unit scores: Using the comprehensive weights, i.e., the weight matrix determined in step S602, weighted summation is performed on each indicator in each grid unit. The specific calculation method is to multiply the measured value of each indicator by the corresponding weight, and then sum up to obtain the score of the grid unit. This process reflects the different importance of different indicators in the evaluation;

[0072] S605. Visualize the scores. Use coordinate drawing to visualize the scores of each grid cell. Use GIS software, data visualization tools, or programming libraries such as Python's Matplotlib and Seaborn to generate intuitive evaluation graphs. The evaluation graphs should be able to clearly display the score distribution and regional degradation status of each grid cell.

[0073] S606. Calculate the average score and graded evaluation. Calculate the average score of all grid unit scores in the entire detection area as the average score of the area. Then, according to the preset grading standards such as excellent, good, medium, poor, etc., compare the average score with the grading standard to determine the degradation level of the stone cultural relic area. The grading standard should be formulated based on historical data, expert opinions and the actual needs of cultural relic protection. Finally, generate an assessment report based on the assessment results, including assessment diagrams, average scores, degradation levels and recommended measures.

[0074] (III) Beneficial effects

[0075] Compared with the prior art, the technical solution of this application has the following beneficial technical effects:

[0076] This method effectively solves the problem of cultural relics pollution and damage that may be caused by direct contact measurement in traditional methods through detailed inspection preparation, including precise positioning of the inspection area, pasting of rulers as reference datums, and application of thermal excitation. The application of thermal excitation changes the surface temperature distribution of cultural relics, enhances the sensitivity of thermal infrared imaging, and helps to more accurately capture the subtle differences in surface diseases of cultural relics. Secondly, in the thermal infrared imaging stage, high-precision thermal infrared imaging instruments in a stable state are used to ensure the clarity of imaging and the accuracy of data. This step not only avoids the subjectivity of human observation, but also improves the inspection efficiency and the reliability of data acquisition, laying a solid foundation for subsequent image and data processing. In the image and data processing link, professional image processing software such as Image J is used to process optical images, and the ratio of pixels to length is converted by rulers to accurately measure the surface detachment area and crack size. At the same time, the thermal infrared images are imported into special analysis software such as InfRec Analyzer NS9500Standard exports temperature information data and realizes multi-dimensional quantitative analysis of diseases. This comprehensive processing method not only improves data accuracy, but also enriches the dimensions of disease evaluation. The grid division and data attribution steps divide the grids reasonably and number them, accurately attribute each data to the corresponding grid units, and realize the spatial subdivision of the detection area and accurate data docking. This step facilitates the subsequent data normalization and weight calculation, and also ensures the scientificity and rationality of the evaluation system construction. In the data normalization and weight calculation stage, by clarifying the positive and negative indicators and performing normalization processing, the differences between data of different dimensions are eliminated, providing a unified standard for subsequent comprehensive evaluation. At the same time, the comprehensive weight is calculated by combining the entropy method and the AHP hierarchical analysis method. , which not only takes into account the objective laws of the data, but also incorporates expert experience and actual conditions, making the weight distribution more fair and reasonable. Finally, in the construction and scoring of the evaluation system, the evaluation system is constructed according to the characteristics and needs of the surface deterioration of stone cultural relics, and the grid unit score is obtained by weighted summation using comprehensive weights, and the evaluation results are intuitively displayed through coordinate drawing. This step not only realizes the quantitative evaluation of the degree of deterioration of the surface of cultural relics, but also clarifies the deterioration level through grading standards, providing a scientific basis and precise guidance for the protection and restoration of cultural relics. In summary, this method effectively overcomes the limitations of traditional methods through a series of scientific and systematic steps and technical means, and realizes a non-contact, high-precision, multi-dimensional quantitative evaluation of the degree of deterioration of the surface of stone cultural relics, with significant beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Figure 1 This is an overall flow chart of a method for evaluating the degree of surface deterioration of stone cultural relics based on thermal infrared imaging according to the present invention;

[0078] Figure 2A surface damage parameter map for obtaining a surface deterioration degree evaluation method of a stone cultural relic surface based on thermal infrared imaging according to the present invention;

[0079] Figure 3 This is a temperature parameter information diagram of a method for evaluating the degree of surface deterioration of stone cultural relics based on thermal infrared imaging according to the present invention;

[0080] Figure 4 A monitoring area grid division diagram of a method for evaluating the degree of surface deterioration of stone cultural relics based on thermal infrared imaging according to the present invention;

[0081] Figure 5 It is a comprehensive score map of monitoring area units of a method for evaluating the degree of surface deterioration of stone cultural relics based on thermal infrared imaging according to the present invention;

[0082] Figure 6 This is a statistical graph of the number of units of different degradation levels in a method for evaluating the degree of surface degradation of stone cultural relics based on thermal infrared imaging according to the present invention. DETAILED DESCRIPTION

[0083] 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.

[0084] Combination Figure 1-Figure 6 As shown, a method for evaluating the degree of deterioration of the surface of stone cultural relics based on thermal infrared imaging of the present invention comprises the following steps:

[0085] S10, test preparation, determine the area of ​​stone cultural relics to be tested, and make detailed marks to ensure that the test area is accurate, paste a ruler on the edge of the test area as a reference for subsequent image processing and data analysis, prepare thermal excitation equipment, and apply thermal excitation to the target area to change the surface temperature distribution of the cultural relics, so that thermal infrared imaging can capture the difference;

[0086] Step S10 specifically includes the following steps:

[0087] S101. Determine the area to be tested, carefully survey the stone cultural relics, and identify the specific area to be tested. This is usually based on the history, preservation status, and possible signs of deterioration such as cracks and shedding of the cultural relics. Use marking tools such as chalk, markers or labels to clearly mark the boundaries of the test area on the surface of the cultural relics to ensure that subsequent testing work can be concentrated in this area;

[0088] S102, sticking the ruler, selecting a suitable position to stick the ruler on the edge of the detection area. The ruler should be firmly stuck and not easy to fall off or shift, and its scale should be clearly visible. Ensure that the direction of the ruler is consistent with the main dimensions of the detection area, such as length and width, so that it can be used as a reference benchmark in subsequent image processing and data analysis. Record the sticking position and scale information of the ruler for accurate reference in subsequent steps;

[0089] S103, prepare thermal excitation equipment, select appropriate thermal excitation equipment according to the type of cultural relics and detection requirements, the thermal excitation equipment can be a heat source generator, a heating lamp, an infrared radiator, etc., check the working status of the thermal excitation equipment to ensure that it can work normally and generate stable heat output, and adjust the layout and power of the thermal excitation equipment according to the size and shape of the detection area to ensure that thermal excitation can be evenly applied to the target area;

[0090] S104. Apply thermal excitation. Under the premise of ensuring the safety of the cultural relics and not affecting their original state, apply thermal excitation to the inspection area. The thermal excitation can be applied in the form of continuous heating or intermittent heating, depending on the material of the cultural relic and the inspection requirements. Observe the changes in the surface temperature distribution of the cultural relic to ensure that the thermal excitation effect reaches the expected effect. A thermal imager or other temperature measurement tools can be used for preliminary inspection to record the time of applying the thermal excitation, the temperature range and the temperature changes on the surface of the cultural relic to provide a reference for subsequent thermal infrared imaging and data analysis.

[0091] By refining step S10, specific and effective solutions are provided for these problems. First, through step S101, the area to be inspected is clarified and carefully surveyed, which ensures the pertinence and accuracy of the inspection work and avoids the waste of resources and unnecessary interference of cultural relics that may be caused by blind inspection. At the same time, the use of marking tools to clearly mark the boundaries of the inspection area provides clear guidance for subsequent inspection work and improves work efficiency. Secondly, the measure of pasting the ruler in step S102 provides a reliable reference benchmark for subsequent image processing and data analysis. The firm pasting and clear scale of the ruler ensure the accuracy of data measurement and reduce the errors caused by unclear reference benchmarks. In addition, recording the pasting position and scale information of the ruler facilitates accurate reference in subsequent steps and enhances the traceability and reliability of the data. Thirdly, preparing the heat shock in step S103 The detailed requirements for the excitation equipment ensure the safety and effectiveness of the thermal excitation process. Appropriate thermal excitation equipment is selected according to the type of cultural relics and detection requirements, and its working status is checked to avoid detection failure or damage to cultural relics due to improper equipment or malfunction. At the same time, the layout position and power of the thermal excitation equipment are adjusted to ensure uniform heating of the target area and improve the sensitivity and accuracy of thermal infrared imaging. Finally, the specific operation of applying thermal excitation in step S104 not only ensures the safety of cultural relics, but also flexibly responds to different cultural relic materials and detection requirements through continuous or intermittent heating, observes and records changes in the surface temperature distribution of cultural relics, and provides rich original data for subsequent thermal infrared imaging and data analysis. This meticulous operation process not only improves the accuracy and reliability of detection, but also provides more scientific and systematic technical support for cultural relic protection.

[0092] S20, thermal infrared imaging: transport the thermal infrared imaging instrument to the inspection site, ensure that the instrument is in a stable state, adjust the focus and camera mode of the thermal infrared imaging instrument to ensure that the thermal image of the target area can be clearly captured, perform thermal infrared imaging of the target area, and record and save the imaging results;

[0093] Step S20 specifically includes the following steps:

[0094] S201. Transport and place the instrument. Safely transport the thermal infrared imaging instrument and its accessories to the testing site. Select a stable, unobstructed and well-ventilated location to place the instrument to ensure that the instrument will not be disturbed by the external environment during the testing process.

[0095] S202, Instrument inspection and preparation: Check whether the appearance of the instrument is intact, without damage or loose parts, confirm that the instrument battery or external power supply is connected and has sufficient power, start the instrument according to the instrument manual, and wait for the instrument to enter a stable state;

[0096] S203, adjust the focus and camera mode, use the focus adjustment knob or button on the instrument to adjust the focus according to the actual distance of the target area to ensure that the image is clear, enter the instrument's setting menu, select the appropriate camera mode, including temperature range, color mapping, etc., so as to clearly display the thermal difference of the target area, preview the adjusted image, and ensure that there is no blur, distortion or overexposure;

[0097] S204, aiming at the target area and imaging, aiming the lens of the instrument at the target area of ​​the stone cultural relic to be detected, ensuring that the entire area is within the field of view, paying attention to avoid interference from direct sunlight or other heat sources, keeping the detection environment relatively stable, pressing the imaging button or triggering the imaging function, starting thermal infrared imaging of the target area, observing the real-time image on the instrument display screen, and ensuring that the imaging process proceeds smoothly;

[0098] S205. Record and save the imaging results. After the imaging is completed, check and record the imaging results on the instrument immediately. Pay attention to check whether the image is clear and complete, and mark any abnormal or suspected damaged areas. Use the instrument's built-in storage function or an external storage device such as an SD card, USB flash drive, etc. to save the imaging results. Make sure the file name and storage path are clear and unambiguous to facilitate subsequent search and use.

[0099] Step S201 emphasizes the importance of instrument transportation and placement. By selecting a stable, unobstructed and well-ventilated location to place the instrument, the interference of the external environment on the imaging process is effectively avoided, ensuring the stability and accuracy of the imaging. Secondly, the instrument inspection and preparation in step S202 ensures that the instrument is in the best working condition before testing. Checking the instrument appearance, battery power, power-on operation, etc. not only ensures the safety of the instrument, but also avoids imaging failure or data loss due to instrument failure. Thirdly, the adjustment of the focus and camera mode in step S203 ensures the clarity of the imaging image and the accurate display of thermal differences through fine adjustment. Select the appropriate camera mode, such as the temperature range. , color mapping, etc., make the imaging results more intuitive and easy to analyze. In step S204, the process of aligning the target area and imaging is guided in detail, avoiding imaging quality problems caused by external factors such as lens offset and direct sunlight. At the same time, maintaining a relatively stable detection environment further improves the accuracy and reliability of imaging. Finally, step S205 emphasizes the importance of recording and saving imaging results. Imaging results are checked and recorded in a timely manner, and abnormal or suspected damaged areas are marked, which provides an important basis for subsequent data analysis and disease assessment. At the same time, the imaging results are saved using the instrument's built-in storage function or an external storage device to ensure data integrity and traceability.

[0100] S30, image and data processing, import the optical image into Image J software to observe the basic morphology and details of the surface of the cultural relic. In Image J, use the Set scale function to convert the ratio of pixels to length according to the ruler, use the Polygon function to outline and calculate the area of ​​the surface detachment on the image, record the relevant data, determine and record whether there are cracks on the surface of the cultural relic. If there are, use the Straight function to measure the length and width of each crack, import the thermal infrared image into InfRec Analyzer NS9500 Standard software, and export the temperature information data of the target area;

[0101] The specific operation steps in step S30 include:

[0102] S301, importing optical images into Image J, opening Image J software, selecting the "Open..." option in the "File" menu, browsing and importing the required optical image files, and confirming that the images are correctly loaded and displayed in the main window of Image J;

[0103] S302, observe the surface morphology of the cultural relic, use the zoom and pan tools of Image J to carefully observe the basic morphology and details of the surface of the cultural relic, and adjust the brightness and contrast of the image to observe the surface features more clearly;

[0104] S303, set the ratio of pixels to length. In Image J, find the "SetScale..." function under the "Analyze" menu. According to the ruler in the image, such as a reference object with a known length, enter the actual length value and set the corresponding unit, such as millimeters or centimeters. Click "OK" to confirm. At this time, Image J will automatically convert the ratio of pixels to length.

[0105] S304, outline and calculate the area of ​​the detached part, switch to the "Freehand Selections" or "PolygonSelections" tool depending on the Image J version, outline the detached part of the surface of the cultural relic on the image, and ensure that the outline accurately covers the entire detached area. Use the "Measure..." function under the "Analyze" menu to calculate and display the area of ​​the outlined area, and record the relevant data;

[0106] S305. Determine and record the cracks. Carefully observe the surface of the cultural relic to determine whether there are cracks. If there are cracks, use the "Straight Line Selection" tool or a similar tool to draw straight line segments on each crack to mark its position and direction. Use the measurement function of Image J to measure and record the length and width of each crack. It may be necessary to make precise measurements through visual estimation or with the help of other tools.

[0107] S306, importing the thermal infrared image into InfRec Analyzer NS9500 Standard, opening the InfRecAnalyzer NS9500 Standard software, selecting an appropriate file import option, and browsing and importing the thermal infrared image file generated in step S20;

[0108] S307. Export the target area temperature information data. In InfRec Analyzer NS9500 Standard, use the tools provided by the software to locate and select the target area. According to the functions and interface of the software, select the option to export the temperature information data, set the export file format, path and parameters to ensure that valid data containing the target area temperature information can be exported. Click "Export" or a similar button to complete the data export process and save the exported data file.

[0109] Through steps S301 to S305, the optical images were processed in detail using Image J software. Not only were the basic morphology and details of the surface of the cultural relics observed, but also the surface damage of the cultural relics was accurately measured and recorded by setting the pixel-to-length ratio, outlining and calculating the area of ​​the detached parts, judging and recording the crack conditions, etc. This process not only improved the objectivity of the evaluation, but also made the evaluation results more accurate and quantifiable, providing an important basis for subsequent data analysis and disease control. Secondly, steps S306 to S307 introduced the InfRec Analyzer NS9500 Standard software to process the thermal infrared images. By exporting the temperature information data of the target area, the potential of thermal infrared imaging technology was further explored. This step not only enriched the evaluation methods, but also made the evaluation results more comprehensive and in-depth. By comparing the optical images and thermal infrared images, the temperature distribution on the surface of the cultural relics can be more intuitively understood, so as to more accurately judge the type, degree and scope of the disease.

[0110] S40, grid division and data attribution, reasonably dividing the grid according to the size and shape of the detection area, and numbering each grid unit, and attributing the previously recorded data such as the detachment area, crack length, width and temperature information to the corresponding grid unit according to the grid division result;

[0111] The step S40 specifically includes the following steps:

[0112] S401, determine the grid division scheme, design a reasonable grid division scheme according to the size, shape and detection requirements of the detection area, consider the size and shape of the grid (such as square, rectangle, hexagon, etc.) and the overlap or gap between the grids, ensure that the grid division can fully cover the detection area, and facilitate subsequent data processing and analysis;

[0113] S402, grid division and numbering, using drawing software such as AutoCAD, GIS software or hand-drawn sketches to draw a grid on the detection area according to the determined grid division scheme, assigning a unique number to each grid unit to ensure the continuity and easy identification of the numbering, and marking important reference points or boundaries on the grid map for subsequent data attribution and verification;

[0114] S403, sorting and classifying data, reviewing previously recorded data such as the shedding area, crack length, width, and temperature information, ensuring the accuracy and completeness of the data, and sorting and classifying the data according to the type and characteristics of the data, such as classifying the shedding area data into one category, the crack length and width data into another category, and the temperature information data into another category;

[0115] S404, data is assigned to grid units. According to the grid division result and the spatial location information of the data, the classified data is assigned to the corresponding grid unit. For each grid unit, its number and all relevant data belonging to the unit are recorded. Tools such as tables, databases or GIS systems can be used to store and manage these data for subsequent query and analysis;

[0116] S405. Verify the accuracy of data attribution. Verify the data attribution process to ensure that each data item is correctly attributed to the corresponding grid unit. Visualization tools such as GIS software can be used to display the results of grid division and data attribution to visually check the accuracy and consistency of the data.

[0117] S406. Record and save the results, record the grid division results, data attribution, and any problems or precautions found during the verification process, and save all relevant data files, charts and records for subsequent analysis and report writing.

[0118] Through step S401, the grid division scheme is determined. According to the actual situation and detection requirements of the detection area, a reasonable grid division scheme is designed to ensure the comprehensiveness, rationality and operability of the grid division, which not only facilitates the subsequent data processing and analysis, but also improves the efficiency and accuracy of data processing. Then, step S402 realizes the precise division and identification of the detection area by dividing the grid and numbering it. The grid is drawn using professional drawing software or hand-drawn sketches, and a unique number is assigned to each grid unit, ensuring that the spatial location information of the data is clear and accurate, which provides a basis for subsequent data attribution and verification. In step S403, the previously recorded disease data is sorted and classified to make the data more orderly and easy to manage. The data is sorted and organized according to its type and characteristics, which not only improves the readability of the data, but also provides convenience for subsequent data analysis. In step S404, the sorted and classified data are assigned to the corresponding grid units, realizing spatial management and analysis of the data. This step ensures that each grid unit contains complete disease data, providing comprehensive data support for subsequent data analysis and disease assessment. In order to further ensure the accuracy of data attribution, step S405 verifies the data attribution process. By using visualization tools such as GIS software to display the results of grid division and data attribution, the accuracy and consistency of the data can be checked intuitively, and errors can be discovered and corrected in a timely manner. Finally, step S406 records the grid division results, data attribution, and problems or precautions found during the verification process, and saves all relevant data files, charts, and records. This not only provides complete information support for subsequent analysis and report writing, but also ensures the traceability and verifiability of the data.

[0119] S50, data normalization and weight calculation, clarify which indicators are positive indicators such as temperature uniformity, which are negative indicators such as shedding area and crack length, normalize the data to eliminate dimensional differences, facilitate subsequent calculations, use the entropy method to calculate the objective weight of each indicator, ensure that the actual situation reflected by the data is fairly reflected in the evaluation system, combine the AHP hierarchical analysis method to determine the subjective weight of each indicator, comprehensively consider expert opinions and actual conditions, combine the objective weight with the subjective weight, and calculate the comprehensive weight of each indicator;

[0120] The step S50 specifically includes the following steps:

[0121] S501. Clarify the positive and negative directions of the indicators and analyze the nature of the indicators: According to the direction of the impact of the evaluation indicators on cultural relics protection or evaluation targets, clarify which indicators are positive indicators such as temperature uniformity, the larger the value, the more beneficial it is to cultural relics protection, and which indicators are negative indicators such as detached area and crack length, the larger the value, the more serious the damage to the cultural relics, list all the indicators that need to be evaluated, and mark their positive and negative directions;

[0122] S502, data normalization processing, selecting an appropriate normalization method such as maximum-minimum normalization, Z-score normalization, etc. according to the characteristics and requirements of the data to eliminate the influence of different dimensions and magnitudes on data analysis, and converting all data according to the selected normalization method so that it falls into a unified numerical range such as [0,1];

[0123] The positive indicators are normalized:

[0124]

[0125] Negative indicator normalization:

[0126]

[0127] Where: is the jth index of the ith unit, i = 1, 2, 3, ... n; j = 1, 2, 3, ... m

[0128] S503, calculating the objective weight of the entropy method, organizing the normalized data into a decision matrix, wherein the rows represent the evaluation objects and the columns represent the evaluation indicators, calculating the information entropy of each evaluation indicator according to the definition and calculation formula of entropy, reflecting the discrete degree of its data distribution, and calculating the difference coefficient using the information entropy. The larger the difference coefficient, the higher the importance of the indicator in the evaluation system. Calculate the objective weight of the entropy method of each evaluation indicator according to the difference coefficient;

[0129] Use the following formula to calculate the weights of different indicators of the unit

[0130]

[0131] The entropy of the jth term is calculated using the following formula:

[0132]

[0133] The coefficient of variation for the jth term is calculated using the following formula:

[0134] d j =1-e j

[0135] Use the following formula to calculate the objective weight of each indicator:

[0136]

[0137] S504. Determine subjective weights by applying AHP. Divide evaluation objectives, evaluation indicators, and decision-making plans into hierarchical structures, invite experts to compare indicators in the same hierarchy, give scores based on their importance, construct a judgment matrix, and use mathematical methods to calculate the eigenvector and maximum eigenvalue of the judgment matrix. The eigenvector is the relative importance ranking of each indicator, i.e., the subjective weight. Perform consistency checks on the judgment matrix to ensure that the expert's scoring results are logically consistent.

[0138] The important coefficients of objective weight and subjective weight are calculated using the following formula:

[0139]

[0140] S505, calculation of comprehensive weights, selecting appropriate comprehensive weight calculation methods such as simple average method, weighted average method, etc., combining the objective weights obtained by the entropy method and the subjective weights obtained by the AHP hierarchical analysis method, and calculating the comprehensive weights of each evaluation index according to the selected method to ensure that the actual situation reflected by the data is fairly reflected in the evaluation system;

[0141] The comprehensive weight is calculated using the following formula:

[0142]

[0143] S506. Verify and adjust the results. Verify the calculated comprehensive weight to ensure that it is consistent with the actual situation and has no obvious logical errors.

[0144] Step S501 clarifies the positive and negative nature of the indicators, providing a clear direction for subsequent data processing and analysis. By analyzing the nature of the indicators, the evaluation indicators are divided into positive indicators and negative indicators, which helps to more accurately understand the impact of each indicator on cultural relics protection or evaluation goals, and lays the foundation for subsequent data normalization and weight calculation. Secondly, step S502 performs data normalization to eliminate the impact of different dimensions and magnitudes on data analysis, so that all data can be compared and analyzed within a unified numerical range. This step not only improves the efficiency and accuracy of data analysis, but also ensures the fairness and objectivity of the evaluation results. In step S503, the objective weight of the evaluation indicator is calculated by the entropy method, which reflects the degree of discreteness of the data distribution and determines the importance of each indicator in the evaluation system accordingly. This method avoids the subjective interference of human factors in weight allocation. , making the weight distribution more scientific and reasonable. At the same time, step S504 introduces the AHP hierarchical analysis method to determine the subjective weight. Through expert scoring and construction of the judgment matrix, the subjective judgment of the experts is converted into quantitative indicators and combined with the objective weight. This step fully considers the professional knowledge and experience of the experts, making the evaluation results more comprehensive and in-depth. Step S505 combines the objective weight and the subjective weight by selecting a suitable comprehensive weight calculation method to calculate the comprehensive weight of each evaluation indicator. This step ensures that the actual situation reflected by the data is fairly reflected in the evaluation system and improves the accuracy and reliability of the evaluation results. Finally, step S506 verifies and adjusts the calculated comprehensive weight to ensure that it is consistent with the actual situation and has no obvious logical errors. This step further improves the evaluation process and improves the credibility and application value of the evaluation results.

[0145] S60. Evaluation system construction and scoring. According to the characteristics of surface deterioration of stone cultural relics and actual needs, an evaluation system and corresponding matrix are constructed. The comprehensive weight is used to perform weighted summation on the indicators in each grid unit to obtain the score of the grid unit. The score of each grid unit is visualized through coordinate mapping to form an intuitive evaluation diagram. The average score of the entire detection area is calculated, and the degree of deterioration of the stone cultural relic area is determined according to preset grading standards such as excellent, good, medium, and poor.

[0146] The step S60 specifically includes the following steps:

[0147] S601. Selection and definition of evaluation indicators. According to the characteristics of surface deterioration of stone cultural relics and actual needs, specific evaluation indicators should be selected and defined. These indicators should be able to fully reflect the deterioration of cultural relics, such as weathering degree, crack density, peeling area, stain type and distribution, microbial erosion degree, etc.

[0148] S602. Construct an evaluation system and weight matrix. Construct an evaluation system framework. Use appropriate methods such as AHP and Delphi method to determine the weight of each evaluation indicator and construct a weight matrix. The weight should reflect the importance and relative contribution of each indicator in the evaluation system.

[0149] S603, data collection and preprocessing, using professional equipment or tools to collect data for various indicators in each grid unit, and clean, convert and standardize the collected data to ensure the consistency and comparability of the data, laying the foundation for subsequent analysis;

[0150] S604, weighted summation to calculate grid unit scores: Using the comprehensive weights, i.e., the weight matrix determined in step S602, weighted summation is performed on each indicator in each grid unit. The specific calculation method is to multiply the measured value of each indicator by the corresponding weight, and then sum up to obtain the score of the grid unit. This process reflects the different importance of different indicators in the evaluation;

[0151] S605. Visualize the scores. Use coordinate drawing to visualize the scores of each grid cell. Use GIS software, data visualization tools, or programming libraries such as Python's Matplotlib and Seaborn to generate intuitive evaluation graphs. The evaluation graphs should be able to clearly display the score distribution and regional degradation status of each grid cell.

[0152] S606. Calculate the average score and graded evaluation. Calculate the average score of all grid unit scores in the entire detection area as the average score of the area. Then, according to the preset grading standards such as excellent, good, medium, poor, etc., compare the average score with the grading standard to determine the degradation level of the stone cultural relic area. The grading standard should be formulated based on historical data, expert opinions and the actual needs of cultural relic protection. Finally, generate an assessment report based on the assessment results, including assessment diagrams, average scores, degradation levels and recommended measures.

[0153] Step S601 ensures the comprehensiveness and pertinence of the evaluation by selecting and defining specific evaluation indicators. These indicators cover multiple aspects such as weathering degree, crack density, peeling area, stain type and distribution, and microbial erosion degree, which can comprehensively reflect the deterioration of cultural relics and provide a rich data basis for subsequent analysis. Secondly, step S602 constructs an evaluation system and weight matrix, and uses scientific methods to determine the weight of each evaluation indicator to ensure the fairness and objectivity of the evaluation. The construction of the weight matrix reflects the importance and relative contribution of each indicator in the evaluation system, making the evaluation results more reasonable and credible. In step S603, data accuracy and consistency are ensured through data collection and preprocessing. Professional equipment or tools are used to collect data, and the data is cleaned, converted, and standardized to eliminate differences and interference factors between data, laying a solid foundation for subsequent analysis. Step S604 calculates the grid units by weighted summation. The score reflects the different importance of different indicators in the evaluation. This step multiplies the measured value of each indicator by the corresponding weight and sums them up to obtain a score that can reflect the comprehensive degradation status of the grid unit, making the evaluation result more accurate and specific. Step S605 presents the evaluation results in an intuitive way through score visualization. The evaluation map is generated by coordinate drawing, which clearly shows the score distribution and regional degradation status of each grid unit, making the evaluation result easier to understand and accept. Finally, step S606 comprehensively evaluates the degradation status of the entire detection area by calculating the average score and grading evaluation. The average score is calculated and compared with the preset grading standard to determine the degradation level of the stone cultural relic area, and an evaluation report including evaluation map, average score, degradation level and recommended measures is generated. This step not only provides strong data support for cultural relic protection work, but also provides a scientific basis for the formulation of subsequent protection measures.

[0154] Taking the rock paintings in Damaidi, Ningxia, which are the eighth batch of national key cultural relics, as an example, the implementation includes the following steps:

[0155] Thermal stimulation: record the ambient temperature, select the area to be tested, keep the surface of the area dry, stick a ruler on the target area, and then perform thermal stimulation on the area for five minutes.

[0156] Thermal infrared imaging: Adjust the focus of the infrared thermal imager so that the lens is perpendicular to the rock surface. Make sure that the inspection area and the scale are within the field of view, and then use the infrared thermal imager to take pictures.

[0157] Photo acquisition: The infrared thermal images and optical images acquired by the infrared thermal imager are transferred to the computer.

[0158] Optical image processing: The optical images were imported into the software Image J to obtain surface damage information; the infrared thermal images were imported into the software InfReC Analyzer NS9500 Standard to obtain temperature information.

[0159] Acquisition of surface damage parameters: Use the Set scale function in Image J to convert the proportional relationship between pixel distance and actual distance, then use the Straight tool to depict the crack edge, and then use the Analyze tool to export the number, length, width and coordinate information of the cracks; use the Polygon tool to depict the detached area, and then use Analyze to export the detached area and coordinate information.

[0160] Acquisition of temperature parameter information: Define the target area in the software InfReC Analyzer NS9500 Standard and export the temperature and coordinate information.

[0161] Grid division: The area to be detected is divided into grids. In this embodiment, the size of a pixel grid is 0.216*0.216 cm, and 20*20 pixels are counted as a statistical unit. Therefore, the target area has a total of 252 (21*12) units.

[0162] Data statistics: The surface damage parameters and temperature data are attributed to the corresponding units using the coordinate information, as shown in Table 1.

[0163] Table 1 Grid unit data information

[0164]

[0165]

[0166] Data standardization: The evaluation indicators are divided into positive indicators and negative indicators. The average temperature and the lowest temperature are positive indicators, and the rest are negative indicators. The two types of indicators are normalized separately, and the positive indicators are calculated as follows:

[0167]

[0168] Negative indicators are calculated as follows:

[0169]

[0170] Where: α ij is the jth index of the ith unit, i=1, 2, 3, ...n; j=1, 2, 3, ...m; in this embodiment, n=252, m=7.

[0171] Calculate sample weights:

[0172]

[0173] Calculate the entropy of the jth item:

[0174]

[0175] Calculate the coefficient of variation for the jth term:

[0176] d j =1-e j (1.5)

[0177] Calculate objective weights:

[0178]

[0179] The entropy value, coefficient of variation and objective weight of each indicator are shown in Table 2.

[0180] Table 2 Objective weights

[0181]

[0182]

[0183] A surface quality evaluation system for stone cultural relics is constructed, as shown in Table 3.

[0184] Table 3 Quality evaluation system

[0185]

[0186] Construct the judgment matrices of project AB, B1-C, and B2-C as shown in equations 1.7 to 1.9.

[0187]

[0188] The AHP hierarchical analysis results of different projects are shown in Tables 4 to 6.

[0189] Table 4 AHP hierarchical analysis results of project AB

[0190]

[0191]

[0192] Table 5 Results of AHP analysis of projects B1-C

[0193]

[0194] Table 6 Results of AHP analysis of project B2-C

[0195]

[0196] According to the above AHP hierarchical analysis results, the subjective weight of each indicator (C1~C7) is calculated: W j =(26.540%, 15.833%, 6.513%, 20.385%, 6.621%, 11.813%, 36.181%) The following formula is used to calculate the important coefficient α of the objective weight and subjective weight of each indicator j and β j :

[0197]

[0198] Where: v j is the objective weight, w j It is a subjective weight.

[0199] The comprehensive weight is calculated using the following formula, and the comprehensive weight of the indicators is shown in Table 7.

[0200]

[0201] Table 7 Comprehensive weights of indicators

[0202]

[0203] Unit comprehensive score: The comprehensive evaluation score of each unit is plotted into a heat map according to the coordinates, and the degree of degradation and location distribution of the target area can be obtained, as shown in the figure below.

[0204] Degradation level classification: Based on on-site testing, the degradation level is divided into four levels: slight, moderate, severe, and extremely severe, as shown in Table 8.

[0205] Table 8 Degradation level classification

[0206]

[0207] Degraded unit statistics: Count the number of units at each degradation level and draw them into a histogram to obtain the distribution of the number of units at different degradation levels in the target area, as shown in the figure below.

[0208] Average degradation degree of the region: The average comprehensive score of all units is 0.746, which means that the detection area belongs to the serious degradation level and requires frequent monitoring and timely protection.

[0209] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0210] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for evaluating the degree of surface deterioration of stone cultural relics based on thermal infrared imaging, characterized in that: The following steps are involved: S10, test preparation, determine the area of ​​stone cultural relics to be tested, and make detailed marks to ensure that the test area is accurate, paste a ruler on the edge of the test area as a reference for subsequent image processing and data analysis, prepare thermal excitation equipment, and apply thermal excitation to the target area to change the surface temperature distribution of the cultural relics, so that thermal infrared imaging can capture the difference; S20, thermal infrared imaging: transport the thermal infrared imaging instrument to the inspection site, ensure that the instrument is in a stable state, adjust the focus and camera mode of the thermal infrared imaging instrument to ensure that the thermal image of the target area can be clearly captured, perform thermal infrared imaging of the target area, and record and save the imaging results; S30, image and data processing, import the optical image into Image J software to observe the basic morphology and details of the surface of the cultural relic. In Image J, use the Set scale function to convert the ratio of pixels to length according to the ruler, use the Polygon function to outline and calculate the area of ​​the surface detachment on the image, record the relevant data, determine and record whether there are cracks on the surface of the cultural relic. If there are, use the Straight function to measure the length and width of each crack, import the thermal infrared image into InfRec Analyzer NS9500 Standard software, and export the temperature information data of the target area; S40, grid division and data attribution, reasonably dividing the grid according to the size and shape of the detection area, and numbering each grid unit, and attributing the previously recorded data such as the detachment area, crack length, width and temperature information to the corresponding grid unit according to the grid division result; S50, data normalization and weight calculation, clarify which indicators are positive indicators such as temperature uniformity, which are negative indicators such as shedding area and crack length, normalize the data to eliminate dimensional differences, facilitate subsequent calculations, use the entropy method to calculate the objective weight of each indicator, ensure that the actual situation reflected by the data is fairly reflected in the evaluation system, combine the AHP hierarchical analysis method to determine the subjective weight of each indicator, comprehensively consider expert opinions and actual conditions, combine the objective weight with the subjective weight, and calculate the comprehensive weight of each indicator; S60. Evaluation system construction and scoring. According to the characteristics of surface deterioration of stone cultural relics and actual needs, an evaluation system and corresponding matrix are constructed. The comprehensive weight is used to perform weighted summation on the indicators in each grid unit to obtain the score of the grid unit. The score of each grid unit is visualized through coordinate mapping to form an intuitive evaluation diagram. The average score of the entire detection area is calculated, and the degree of deterioration of the stone cultural relic area is determined according to preset grading standards such as excellent, good, medium, and poor.

2. The method for evaluating the degree of surface deterioration of stone cultural relics based on thermal infrared imaging according to claim 1, characterized in that: The step S10 specifically includes the following steps: S101. Determine the area to be tested, carefully survey the stone cultural relics, and identify the specific area to be tested. This is usually based on the history, preservation status, and possible signs of deterioration such as cracks and shedding of the cultural relics. Use marking tools such as chalk, markers or labels to clearly mark the boundaries of the test area on the surface of the cultural relics to ensure that subsequent testing work can be concentrated in this area; S102, sticking the ruler, selecting a suitable position to stick the ruler on the edge of the detection area. The ruler should be firmly stuck and not easy to fall off or shift, and its scale should be clearly visible. Ensure that the direction of the ruler is consistent with the main dimensions of the detection area, such as length and width, so that it can be used as a reference benchmark in subsequent image processing and data analysis. Record the sticking position and scale information of the ruler for accurate reference in subsequent steps; S103, prepare thermal excitation equipment, select appropriate thermal excitation equipment according to the type of cultural relics and detection requirements, the thermal excitation equipment can be a heat source generator, a heating lamp, an infrared radiator, etc., check the working status of the thermal excitation equipment to ensure that it can work normally and generate stable heat output, and adjust the layout and power of the thermal excitation equipment according to the size and shape of the detection area to ensure that thermal excitation can be evenly applied to the target area; S104. Apply thermal excitation. Under the premise of ensuring the safety of the cultural relics and not affecting their original state, apply thermal excitation to the inspection area. The thermal excitation can be applied in the form of continuous heating or intermittent heating, depending on the material of the cultural relic and the inspection requirements. Observe the changes in the surface temperature distribution of the cultural relic to ensure that the thermal excitation effect reaches the expected effect. A thermal imager or other temperature measurement tools can be used for preliminary inspection to record the time of applying the thermal excitation, the temperature range and the temperature changes on the surface of the cultural relic to provide a reference for subsequent thermal infrared imaging and data analysis.

3. The method for evaluating the degree of surface deterioration of stone cultural relics based on thermal infrared imaging according to claim 1, characterized in that: The step S20 specifically includes the following steps: S201. Transport and place the instrument. Safely transport the thermal infrared imaging instrument and its accessories to the testing site. Select a stable, unobstructed and well-ventilated location to place the instrument to ensure that the instrument will not be disturbed by the external environment during the testing process. S202, Instrument inspection and preparation: Check whether the appearance of the instrument is intact, without damage or loose parts, confirm that the instrument battery or external power supply is connected and has sufficient power, start the instrument according to the instrument manual, and wait for the instrument to enter a stable state; S203, adjust the focus and camera mode, use the focus adjustment knob or button on the instrument to adjust the focus according to the actual distance of the target area to ensure that the image is clear, enter the instrument's setting menu, select the appropriate camera mode, including temperature range, color mapping, etc., so as to clearly display the thermal difference of the target area, preview the adjusted image, and ensure that there is no blur, distortion or overexposure; S204, aiming at the target area and imaging, aiming the lens of the instrument at the target area of ​​the stone cultural relic to be detected, ensuring that the entire area is within the field of view, paying attention to avoid interference from direct sunlight or other heat sources, keeping the detection environment relatively stable, pressing the imaging button or triggering the imaging function, starting thermal infrared imaging of the target area, observing the real-time image on the instrument display screen, and ensuring that the imaging process proceeds smoothly; S205. Record and save the imaging results. After the imaging is completed, check and record the imaging results on the instrument immediately. Pay attention to check whether the image is clear and complete, and mark any abnormal or suspected damaged areas. Use the instrument's built-in storage function or an external storage device such as an SD card, USB flash drive, etc. to save the imaging results. Make sure the file name and storage path are clear and unambiguous to facilitate subsequent search and use.

4. The method for evaluating the degree of surface deterioration of stone cultural relics based on thermal infrared imaging according to claim 1, characterized in that: The specific operation steps in step S30 include: S301, import the optical image into Image J, open the Image J software, select the "Open..." option in the "File" menu, browse and import the required optical image file, confirm that the image is loaded correctly and displayed in the main window of Image J; S302, observe the surface morphology of the cultural relic, use the zoom and pan tools of Image J to carefully observe the basic morphology and details of the surface of the cultural relic, and adjust the brightness and contrast of the image to observe the surface features more clearly; S303, set the ratio of pixels to length. In Image J, find the "Set Scale..." function under the "Analyze" menu. According to the ruler in the image, such as a reference object with a known length, enter the actual length value and set the corresponding unit, such as millimeters or centimeters. Click "OK" to confirm. At this time, Image J will automatically convert the ratio of pixels to length. S304, outline and calculate the area of ​​the detached part. Switch to the "Freehand Selections" or "PolygonSelections" tool, depending on the Image J version, and outline the detached part of the cultural relic on the image. Make sure that the outline accurately covers the entire detached area. Use the "Measure..." function under the "Analyze" menu to calculate and display the area of ​​the outlined area and record the relevant data. S305. Determine and record the cracks. Carefully observe the surface of the cultural relic to determine whether there are cracks. If there are cracks, use the "Straight Line Selection" tool or similar tools to draw straight line segments on each crack to mark its position and direction. Use the measurement function of Image J to measure and record the length and width of each crack. It may be necessary to make precise measurements through visual estimation or with the help of other tools. S306, importing the thermal infrared image into InfRec Analyzer NS9500 Standard, opening the InfRec Analyzer NS9500 Standard software, selecting an appropriate file import option, and browsing and importing the thermal infrared image file generated in step S20; S307. Export the target area temperature information data. In InfRec Analyzer NS9500 Standard, use the tools provided by the software to locate and select the target area. According to the software functions and interface, select the option to export the temperature information data, set the export file format, path and parameters to ensure that valid data containing the target area temperature information can be exported. Click "Export" or a similar button to complete the data export process and save the exported data file.

5. The method for evaluating the degree of surface deterioration of stone cultural relics based on thermal infrared imaging according to claim 1, characterized in that: The step S40 specifically includes the following steps: S401, determine the grid division scheme, design a reasonable grid division scheme according to the size, shape and detection requirements of the detection area, consider the size and shape of the grid (such as square, rectangle, hexagon, etc.) and the overlap or gap between the grids, ensure that the grid division can fully cover the detection area, and facilitate subsequent data processing and analysis; S402, grid division and numbering, using drawing software such as AutoCAD, GIS software or hand-drawn sketches to draw a grid on the detection area according to the determined grid division scheme, assigning a unique number to each grid unit to ensure the continuity and easy identification of the numbering, and marking important reference points or boundaries on the grid map for subsequent data attribution and verification; S403, sorting and classifying data, reviewing previously recorded data such as the shedding area, crack length, width, and temperature information, ensuring the accuracy and completeness of the data, and sorting and classifying the data according to the type and characteristics of the data, such as classifying the shedding area data into one category, the crack length and width data into another category, and the temperature information data into another category; S404, data is assigned to grid units. According to the grid division result and the spatial location information of the data, the classified data is assigned to the corresponding grid unit. For each grid unit, its number and all relevant data belonging to the unit are recorded. Tools such as tables, databases or GIS systems can be used to store and manage these data for subsequent query and analysis; S405. Verify the accuracy of data attribution. Verify the data attribution process to ensure that each data item is correctly attributed to the corresponding grid unit. Visualization tools such as GIS software can be used to display the results of grid division and data attribution to visually check the accuracy and consistency of the data. S406. Record and save the results, record the grid division results, data attribution, and any problems or precautions found during the verification process, and save all relevant data files, charts and records for subsequent analysis and report writing.

6. The method for evaluating the degree of surface deterioration of stone cultural relics based on thermal infrared imaging according to claim 1, characterized in that: The step S50 specifically includes the following steps: S501. Clarify the positive and negative directions of the indicators and analyze the nature of the indicators: According to the direction of the impact of the evaluation indicators on cultural relics protection or evaluation targets, clarify which indicators are positive indicators such as temperature uniformity, the larger the value, the more beneficial it is to cultural relics protection, and which indicators are negative indicators such as detached area and crack length, the larger the value, the more serious the damage to the cultural relics, list all the indicators that need to be evaluated, and mark their positive and negative directions; S502, data normalization processing, selecting an appropriate normalization method such as maximum-minimum normalization, Z-score normalization, etc. according to the characteristics and requirements of the data to eliminate the influence of different dimensions and magnitudes on data analysis, and converting all data according to the selected normalization method so that it falls into a unified numerical range such as [0,1]; The positive indicators are normalized: Negative indicator normalization: Where: is the jth index of the ith unit, i = 1, 2, 3, ... n; j = 1, 2, 3, ... m S503, calculating the objective weight of the entropy method, organizing the normalized data into a decision matrix, wherein the rows represent the evaluation objects and the columns represent the evaluation indicators, calculating the information entropy of each evaluation indicator according to the definition and calculation formula of entropy, reflecting the discrete degree of its data distribution, and calculating the difference coefficient using the information entropy. The larger the difference coefficient, the higher the importance of the indicator in the evaluation system. Calculate the objective weight of the entropy method of each evaluation indicator according to the difference coefficient; Use the following formula to calculate the weights of different indicators of the unit The entropy of the jth term is calculated using the following formula: The coefficient of variation for the jth term is calculated using the following formula: d j =1-e j Use the following formula to calculate the objective weight of each indicator: S504. Determine subjective weights by applying AHP. Divide evaluation objectives, evaluation indicators, and decision-making plans into hierarchical structures, invite experts to compare indicators in the same hierarchy, give scores based on their importance, construct a judgment matrix, and use mathematical methods to calculate the eigenvector and maximum eigenvalue of the judgment matrix. The eigenvector is the relative importance ranking of each indicator, i.e., the subjective weight. Perform consistency checks on the judgment matrix to ensure that the expert's scoring results are logically consistent. The important coefficients of objective weight and subjective weight are calculated using the following formula: S505, calculation of comprehensive weights, selecting appropriate comprehensive weight calculation methods such as simple average method, weighted average method, etc., combining the objective weights obtained by the entropy method and the subjective weights obtained by the AHP hierarchical analysis method, and calculating the comprehensive weights of each evaluation index according to the selected method to ensure that the actual situation reflected by the data is fairly reflected in the evaluation system; The comprehensive weight is calculated using the following formula: S506. Verify and adjust the results. Verify the calculated comprehensive weight to ensure that it is consistent with the actual situation and has no obvious logical errors.

7. The method for evaluating the degree of surface deterioration of stone cultural relics based on thermal infrared imaging according to claim 1, characterized in that: The step S60 specifically includes the following steps: S601. Selection and definition of evaluation indicators. According to the characteristics of surface deterioration of stone cultural relics and actual needs, specific evaluation indicators should be selected and defined. These indicators should be able to fully reflect the deterioration of cultural relics, such as weathering degree, crack density, peeling area, stain type and distribution, microbial erosion degree, etc. S602. Construct an evaluation system and weight matrix. Construct an evaluation system framework. Use appropriate methods such as AHP and Delphi method to determine the weight of each evaluation indicator and construct a weight matrix. The weight should reflect the importance and relative contribution of each indicator in the evaluation system. S603, data collection and preprocessing, using professional equipment or tools to collect data for various indicators in each grid unit, and clean, convert and standardize the collected data to ensure the consistency and comparability of the data, laying the foundation for subsequent analysis; S604, weighted summation to calculate grid unit scores: Using the comprehensive weights, i.e., the weight matrix determined in step S602, weighted summation is performed on each indicator in each grid unit. The specific calculation method is to multiply the measured value of each indicator by the corresponding weight, and then sum up to obtain the score of the grid unit. This process reflects the different importance of different indicators in the evaluation; S605. Visualize the scores. Use coordinate drawing to visualize the scores of each grid cell. Use GIS software, data visualization tools, or programming libraries such as Python's Matplotlib and Seaborn to generate intuitive evaluation graphs. The evaluation graphs should be able to clearly display the score distribution and regional degradation status of each grid cell. S606. Calculate the average score and graded evaluation. Calculate the average score of all grid unit scores in the entire detection area as the average score of the area. Then, according to the preset grading standards such as excellent, good, medium, poor, etc., compare the average score with the grading standard to determine the degradation level of the stone cultural relic area. The grading standard should be formulated based on historical data, expert opinions and the actual needs of cultural relic protection. Finally, generate an assessment report based on the assessment results, including assessment diagrams, average scores, degradation levels and recommended measures.

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