Infrared nondestructive testing method and system for detecting decay degree of ancient building corbel

Abstract

The present application provides an infrared nondestructive testing method for detecting the decay degree of ancient building look boards, comprising: building a look board infrared image acquisition device; using sunlight as a heat source to take infrared detection images of the look board at 2-3 pm (when the outdoor temperature is higher than the indoor temperature); using a Python-based infrared image processing system to detect and extract the decay area of the look board; calculating the decay area ratio of the look board to determine the decay degree of the look board. This method uses infrared thermal imaging technology to make up for the shortcomings of existing look board decay detection methods, and has the advantages of strong portability, simple operation, suitability for on-site detection of ancient buildings, and non-destructive testing. It provides technical support for the decay degree detection of ancient building look boards and has very important practical significance for the maintenance and repair of ancient building look boards.

Description

Technical Field

[0001] This invention relates to the field of roof board decay detection, and in particular to a rapid and non-destructive method and system for detecting the decay of roof boards in ancient buildings. Background Technology

[0002] my country has a large number of ancient wooden buildings, whose roofs, located at the very top of the structure, serve multiple functions including load-bearing, enclosure, decoration, and protection against the effects of wind, rain, snow, solar radiation, and low winter temperatures, effectively protecting the entire building. Typically, the roof of an ancient wooden building consists of three parts from the outside in: gray tiles, thatching, and roof boards. The roof boards are wooden planks laid flat on the rafters, supporting the thatching, tiles, and enclosing the interior. Due to the unique structural position of the roof boards, they are susceptible to leaks and seepage during service, becoming damp and dark, making them vulnerable to fungal and bacterial decay. This decay always occurs on the outer surface of the roof boards, the surface in contact with the thatching. However, due to the unique structural location of the roof panels in ancient buildings, the exterior is often covered with thatching and gray tiles, making it impossible to directly observe and detect decay from the outside. From the inside, only severe decay that has progressed from the outside to the inside can be observed. Furthermore, the inside of the roof panels is often located in a confined space within the ceiling. Therefore, traditional non-destructive testing methods (visual inspection, tapping, micro-drilling resistance testing, etc.) are unsuitable for detecting the degree of decay, and the testing process is technically challenging. In other words, the difficulty in early detection and quantitative assessment of the degree of decay in ancient wooden structures is a major problem in the preservation of ancient wooden buildings.

[0003] Infrared thermography (IRT) technology, with its advantages of fast detection speed, high efficiency, non-contact operation, low cost, and intuitive results, has a promising future in the field of non-destructive testing of wood. The principle behind IRT for detecting the degree of decay in roof boards is based on the fact that roof boards constantly emit infrared radiation. The difference in radiation temperature between decayed and normal areas directly affects the accuracy of IRT detection. Based on this principle, by acquiring infrared images of the roof board under test, the decayed and normal areas will display different color distributions. Combined with image processing techniques, the degree of decay defects in the roof board can be accurately determined, which is of great significance for the inspection and repair of roof boards in ancient buildings and for maintaining the safety of ancient buildings. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides an infrared non-destructive testing method and system for detecting the degree of decay of roof panels in ancient buildings.

[0005] In a first aspect, embodiments of the present invention provide an infrared non-destructive testing method for detecting the degree of decay of roof panels of ancient buildings, comprising: setting up an infrared image acquisition device for the roof panels; capturing infrared images of the roof panels at the time of 2-3 pm (when the outdoor temperature is higher than the indoor temperature, such as in summer or when there is sunshine); performing image grayscale mapping and smoothing and noise reduction processing on the infrared images to extract decayed areas; calculating the proportion of decayed area of ​​the detected roof panels, and analyzing and determining the degree of decay of the detected roof panels.

[0006] The above-mentioned implementation method can make up for the shortcomings of existing decay detection methods, quickly and intuitively obtain information on the decay defects of roof panels, provide technical support for the assessment of the decay degree of roof panels of ancient buildings, and have great practical significance for the research on the maintenance and repair of roof panels of ancient buildings.

[0007] In conjunction with the first aspect, in the first possible implementation of the first aspect, the infrared detection device for the degree of decay of the ancient building's roof panels is flexibly constructed and can be built using an infrared thermal imager, a tripod, image acquisition software, and a computer. In conjunction with the first aspect, in the second possible implementation of the first aspect, the infrared images of the roof panels are acquired by using the infrared thermal imager to obtain multiple clear infrared images of the roof panels based on the constructed infrared image acquisition device.

[0008] In conjunction with the second possible implementation of the first aspect, in the third possible implementation of the first aspect, the infrared image capture time is 2-3 PM, including: the temperature difference between the decayed and normal eaves panels directly affects the detection effect of the infrared thermal imager, and the maximum temperature difference M between the decayed and normal eaves panels... max The formula is

[0009]

[0010] The inner surface of the roof panel is the side closest to the interior, while the outer surface is the side closest to the roof. The temperature on the inner surface is t0, and the temperature on the outer surface is t1. The density and specific heat capacity of a normal roof panel are ρ1 and c1, respectively, while the density and specific heat capacity of a decayed roof panel are ρ2 and c2, respectively. From Formula 1, it can be concluded that, without considering the material of the roof panel, the difference in heat transfer temperature between a decayed and a normal roof panel depends on the temperature difference between the two sides of the panel. Therefore, better infrared detection results can be obtained in environments with a large temperature difference between indoors and outdoors. Weather monitoring in the area revealed that the temperature difference between indoors and outdoors in ancient buildings is greatest between 2 and 3 PM; therefore, shooting during this time period yields the best infrared detection results.

[0011] The method for acquiring the infrared images of the viewing platform is as follows: based on the constructed infrared image acquisition device for the viewing platform, during the detection period from 2 to 3 pm, the field of view of the infrared thermal imager is adjusted to capture images of the area of ​​the viewing platform under test, and multiple clear infrared images of the viewing platform are acquired.

[0012] In conjunction with the first aspect, in the fourth possible implementation of the first aspect, the grayscale mapping and smoothing denoising processing in the infrared image includes: converting the RGB image captured by infrared imaging into an HSV image, extracting the h value for grayscale mapping; and, based on the grayscale processing, performing Gaussian filtering to remove noise in the infrared image.

[0013] In conjunction with the fourth possible implementation of the first aspect, in the fifth possible implementation of the first aspect, the color information of the infrared image can be mapped one by one to grayscale information, and the color recognition capability of the infrared image grayscale image converted to HSV image is higher than that of the infrared grayscale image mapped from the RGB image.

[0014] In conjunction with the first aspect, in the sixth possible implementation of the first aspect, the infrared detection image of the stencil contains rich information on the degree of decay, and the extraction of the degree of decay information adopts an edge detection method, including: using the Canny edge detection algorithm to obtain the edge of the decayed area; finally, the degree of decay information of the infrared image is obtained.

[0015] Secondly, embodiments of the present invention provide an infrared non-destructive image processing system for detecting the degree of decay of roof panels in ancient buildings. The system includes: an image acquisition module for reading an infrared image with decay information acquired by an infrared image acquisition device; an image preprocessing module for converting the infrared image from RGB to HSV, performing grayscale mapping and filtering to obtain a grayscale image; an image decay region detection module for extracting decay defect information from the infrared image based on the edge detection method of the Canny operator, obtaining the edge of the decay region using the Canny edge detection algorithm, and extracting the edge information of the decay region in the infrared image; and an image decay area calculation module for calculating the proportion of decayed area of ​​the roof panel based on the decay defect information of the infrared image, providing a reference for related research on the assessment of the degree of decay of the roof panel.

[0016] In conjunction with the second aspect, in the first possible implementation of the second aspect, the image preprocessing module includes: a first processing unit for converting the infrared image format to obtain an HSV image, wherein the infrared image undergoes an accurate grayscale conversion process to achieve one-to-one matching of infrared image color information with grayscale values, resulting in a high-discrimination grayscale image; and a second processing unit for performing denoising processing on the high-discrimination grayscale image based on a Gaussian filtering algorithm to obtain a smooth and denoised grayscale image.

[0017] Thirdly, embodiments of the present invention provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of any of the above-described infrared image processing methods for a telescope. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram illustrating the method for acquiring infrared images of ancient building roof panels provided by the present invention;

[0020] Figure 2 This is a flowchart illustrating the infrared non-destructive testing method for detecting the degree of decay of roof panels in ancient buildings, provided by the present invention.

[0021] Figure 3 This is a schematic diagram of the infrared non-destructive testing system for detecting the degree of decay of roof panels in ancient buildings provided by the present invention.

[0022] Figure 4 This is a schematic diagram of the structure of the electronic device provided by the present invention.

[0023] In the picture: 1. Sunlight; 2. Ancient building roof; 3. Infrared thermal imager; 4. Tripod; 5. Computer. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0025] The following is combined Figures 1-4 This invention describes an infrared non-destructive testing method and system for detecting the degree of decay of roof panels in ancient buildings.

[0026] Figure 1 This is a schematic diagram illustrating the method for acquiring infrared images of ancient building roof panels provided by the present invention, as shown below. Figure 1 As shown, at 2-3 pm (when the outdoor temperature is higher than the indoor temperature), sunlight 1 serves as the heat source for infrared detection, providing thermal excitation. Inside the ancient building, the infrared thermal imager 3 is fixed on a tripod 4 and the appropriate shooting distance is adjusted. The infrared thermal imager 3 is used to photograph the roof panel 2 of the ancient building to obtain an infrared detection image of the roof panel. The captured image can be processed in the computer 5 for infrared image grayscale mapping, noise reduction, edge detection of decayed areas, and calculation of decayed area.

[0027] Figure 2 This is a flowchart illustrating the infrared non-destructive testing method for detecting the degree of decay of roof panels in ancient buildings, provided by the present invention. Figure 2 As shown, the method includes:

[0028] S101, Construct an infrared image capturing device for the observation panel to be tested.

[0029] In this embodiment, the infrared image acquisition device for the observation deck is flexibly set up and can be constructed from an infrared thermal imager, a tripod, image acquisition software, and a computer.

[0030] S102 takes infrared images between 2 and 3 pm (when the outdoor temperature is higher than the indoor temperature, such as in summer or when the sun is out).

[0031] Infrared images were captured between 2 and 3 PM. The temperature difference between the decayed and normal eaves panels directly affects the detection performance of the infrared thermal imager. The maximum temperature difference M between the decayed and normal eaves panels... max The formula is

[0032]

[0033] The inner surface of the roof panel is the side closest to the interior, while the outer surface is the side closest to the roof. The temperature on the inner surface is t0, and the temperature on the outer surface is t1. The density and specific heat capacity of a normal roof panel are ρ1 and c1, respectively, while the density and specific heat capacity of a decayed roof panel are ρ2 and c2, respectively. From Formula 1, it can be concluded that, without considering the material of the roof panel, the difference in heat transfer temperature between a decayed and a normal roof panel depends on the temperature difference between the two sides of the panel. Therefore, better infrared detection results can be obtained in environments with a large temperature difference between indoors and outdoors. Weather monitoring in the area revealed that the temperature difference between indoors and outdoors in ancient buildings is greatest between 2 and 3 PM; therefore, shooting during this time period yields the best infrared detection results.

[0034] The method for acquiring the infrared images of the viewing platform is as follows: based on the constructed infrared image acquisition device for the viewing platform, during the detection period from 2 to 3 pm, the field of view of the infrared thermal imager is adjusted to capture images of the area of ​​the viewing platform under test, and multiple clear infrared images of the viewing platform are acquired.

[0035] S103, perform image grayscale mapping and noise reduction processing on the infrared image to extract information about the decayed area.

[0036] The infrared image contains rich information on the decay defects of the roofing board. The decay information of the roofing board is extracted using the Canny edge detection method: First, the infrared detection image of the roofing board is preprocessed, grayscale is converted and noise interference is removed, and the edge of the decayed area is obtained using the Canny edge detection algorithm, and the edge information of the decayed area in the infrared detection image is extracted.

[0037] S104, calculate the percentage of decayed area and analyze to determine the degree of decay of the roof slab.

[0038] Based on the edge information of the decayed area in the infrared detection image, the proportion of the decayed area of ​​the roof board is analyzed to provide a reference for evaluating the degree of decay of the roof board and to determine the degree of decay of the detected roof board.

[0039] The infrared non-destructive testing method for detecting the degree of decay of roof panels in ancient buildings provided in this invention can make up for the shortcomings of existing decay defect detection methods, and obtain a method for detecting the degree of decay of roof panels in ancient buildings that is fast, efficient, non-contact, low-cost, and provides intuitive test results, thus providing technical support for the detection of the degree of decay of roof panels in ancient buildings.

[0040] Corresponding to the infrared non-destructive testing method for detecting the degree of decay of roof panels of ancient buildings provided in the above embodiments, the present invention also provides an embodiment of an infrared non-destructive testing system for detecting the degree of decay of roof panels of ancient buildings. Figure 3 This is a schematic diagram of the infrared image processing system for detecting the degree of decay of roof panels in ancient buildings, provided by the present invention. Figure 3 As shown, the infrared image processing system 20 for detecting the degree of decay of roof panels in ancient buildings includes: an image acquisition module 201, an image preprocessing module 202, an image decay area detection module 203, and an image decay area calculation module 204. The image acquisition module 201 reads infrared images containing decay information acquired by an infrared image acquisition device; the image preprocessing module 202 performs RGB-to-HSV conversion on the infrared image, performs grayscale mapping to obtain a grayscale image, and filters and removes noise; the image decay area detection module 203 extracts decay defect information from the infrared image based on the Canny operator edge detection method; and the image decay area calculation module 204 calculates the proportion of decayed area of ​​the roof panels based on the decay defect information in the infrared image, providing a reference for related research on the assessment of the degree of decay of roof panels.

[0041] Furthermore, the image preprocessing module 202 includes: a first processing unit and a second processing unit.

[0042] The first processing unit is used for the infrared image format conversion to obtain an HSV image. The infrared image is subjected to an accurate grayscale conversion process. The grayscale mapping equation is y = 255 - (17 / 8) * h, which realizes the one-to-one matching of infrared image color information and grayscale value to obtain a high-discrimination grayscale image.

[0043] The second processing unit removes the shooting noise of the infrared image using a Gaussian filtering method.

[0044] The system embodiments provided in this invention are for implementing the above-described method embodiments. For specific processes and details, please refer to the above-described method embodiments, which will not be repeated here.

[0045] Figure 4 This is a schematic diagram of the structure of the electronic device provided by the present invention, such as... Figure 4 As shown, the electronic device 30 may include a processor 301, a communication interface 302, a memory 303, and a communication bus 304. The processor 301, communication interface 302, and memory 303 communicate with each other via the communication bus 304. The processor 301 can call logical instructions in the memory 303 to execute a method for detecting the degree of decay of the roof slab, including: reading the infrared image set acquired by the roof slab infrared image acquisition device; converting the infrared images to HSV format and mapping them to grayscale to obtain a high-discrimination grayscale image; removing the shooting noise of the infrared image based on a Gaussian filtering method; extracting decay defect information from the infrared image based on the Canny operator edge detection method; analyzing the decay defect information of the infrared image; calculating the proportion of decayed area of ​​the roof slab; and determining the degree of decay of the roof slab.

[0046] Furthermore, the logical instructions in the aforementioned memory 303 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0047] On the other hand, the present invention also provides a computer program product, the computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions, wherein when the program instructions are executed by a computer, the computer is able to execute the roof slab decay detection method provided by the above methods, comprising: reading an infrared detection image set acquired by a roof slab infrared image acquisition device; converting the infrared image to HSV format and mapping it to grayscale to obtain a high-discrimination grayscale image; removing the shooting noise of the infrared image based on a Gaussian filtering method; extracting decay defect information of the infrared image based on a Canny operator edge detection method; analyzing the decay defect information of the infrared image, calculating the proportion of decayed area of ​​the roof slab, and determining the degree of decay of the roof slab.

[0048] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements the method for detecting the degree of decay of the roof slab provided in the above embodiments, including: reading an infrared detection image set acquired by an infrared image acquisition device of the roof slab; converting the infrared images to HSV format and mapping them to grayscale to obtain a high-discrimination grayscale image; removing the shooting noise of the infrared images based on a Gaussian filtering method; extracting decay defect information of the infrared images based on a Canny operator edge detection method; analyzing the decay defect information of the infrared images, calculating the proportion of decayed area of ​​the roof slab, and determining the degree of decay of the roof slab.

[0049] The system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0050] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An infrared non-destructive testing method for detecting the degree of decay of roof panels in ancient buildings, characterized in that, The method includes: setting up an infrared image acquisition device for the roof panels of ancient buildings; Infrared images are captured between 2 and 3 pm, provided that the outdoor temperature is higher than the indoor temperature, such as on a sunny summer day. The infrared image is subjected to grayscale mapping and noise reduction processing to extract the edges of decayed areas. Calculate the percentage of decayed roofing area and analyze to determine the degree of decay. Among them, the temperature difference between the decayed and normal eaves panels directly affects the detection effect of the infrared thermal imager, and the maximum temperature difference between the decayed and normal eaves panels is... M The formula for max is The inner surface of the roof veneer is located on the side closest to the interior, while the outer surface is located on the side closest to the roof. The temperature on the inner surface of the roof veneer... t0 Temperature on one side of the outer surface of the sheath t1 Normal sheath density ρ1 Normal heat capacity of heat exchange plate c1 Density of decayed roof boards ρ2 Specific heat capacity of decaying roof board c2 From formula (1), it can be concluded that, without considering the material of the roof board, the temperature difference between the decayed roof board and the normal roof board depends on the temperature difference on both sides of the roof board. Therefore, in an environment with a large temperature difference between indoors and outdoors, better infrared detection results can be obtained. According to the weather monitoring of the local area, the temperature difference between indoors and outdoors of ancient buildings is the largest between 2 and 3 pm. Taking pictures during this period can obtain the best infrared detection effect. The method for acquiring the infrared images of the roof is as follows: based on the constructed infrared image acquisition device for the roof, during the detection period from 2 to 3 pm, the infrared thermal imager is adjusted to a suitable field of view, and the inner surface of the roof to be tested is photographed inside the ancient building to acquire multiple clear infrared images of the roof.

2. The infrared non-destructive testing method for detecting the degree of decay of roof panels in ancient buildings according to claim 1, characterized in that, The infrared image is captured by the infrared image acquisition device built on the rooftop. The infrared image acquisition device is flexibly built and consists of an infrared thermal imager, a tripod, image acquisition software, and a computer.

3. The infrared non-destructive testing method for detecting the degree of decay of roof panels in ancient buildings according to claim 1, characterized in that, The infrared image undergoes grayscale mapping and denoising processing, including: The RGB image captured by infrared is converted into an HSV image with higher color recognition capability. The h value is extracted and grayscale mapping is performed. The mapping equation is y=255-(17 / 8)*h. Based on the grayscale processing, Gaussian filtering is used to remove noise from the infrared image.

4. The infrared non-destructive testing method for detecting the degree of decay of roof panels in ancient buildings according to claim 1, characterized in that, The infrared image of the eaves contains rich decay information, which is extracted using an edge detection method, including: The edges of the decayed region are obtained using the Canny edge detection algorithm, and the decay information of the infrared image is extracted.

5. The infrared non-destructive testing method for detecting the degree of decay of roof panels in ancient buildings according to claim 1, characterized in that, It also includes calculating the percentage of decayed area based on the decay defect information in the infrared images, analyzing the degree of decay of the roof panels, and providing guidance for the assessment, repair and maintenance of the decay degree of the roof panels of ancient buildings.

6. An infrared non-destructive testing system for detecting the degree of decay of roof panels in ancient buildings, characterized in that, The system executes the infrared non-destructive testing method for detecting the degree of decay of the roof panels of ancient buildings as described in claim 1, including: The image acquisition module is used to read infrared images with decay information acquired by the infrared image acquisition device; The image preprocessing module is used to convert the infrared image from RGB to HSV, perform grayscale mapping to obtain a grayscale image, and filter it to remove noise. The image decay region detection module extracts decay defect information from the infrared image based on the Canny operator edge detection method; The roof decay area calculation module is used to calculate the proportion of decay area of ​​the roof based on the decay defect information of the infrared image, providing a reference for related research on roof decay assessment.

7. The system according to claim 6, characterized in that, The image preprocessing module includes: A first processing unit is used for infrared image format conversion to obtain an HSV image, wherein the infrared image is subjected to... The accurate grayscale conversion process enables one-to-one matching of color information and grayscale values ​​in infrared images, resulting in a highly distinguishable grayscale image. The second processing unit performs filtering and denoising processing on the high-discrimination grayscale image based on the Gaussian filtering algorithm to obtain a smooth and denoised grayscale image.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the infrared non-destructive testing method for detecting the degree of decay of the roof panels of ancient buildings as described in any one of claims 1 to 6.

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