JP2023073399A - Evaluation method and evaluation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an evaluation method and an evaluation system capable of facilitating the grasp of the displacement and damage situation of a surface.

SOLUTION: In order to make it possible to identify a crack C1 that may occur on a surface F1 of a structure, measurement points M1 are formed on the surface F1 using a yellow fluorescent paint on top of a white base paint. A photographing device 15 generates an image obtained by photographing each measurement point in a recognizable manner via a bandpass filter 16 that transmits reflected light of blue illumination light to the surface. A control unit 21 of an analysis device 20 compares a first image captured and generated by the photographing device 15 before applying force to the structure with a second image captured and generated by the photographing device 15 in the state where the crack C1 has occurred due to the force applied to the structure, and identifies displacement of the surface F1.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2023,JPO&INPIT

Description

TECHNICAL FIELD The present invention relates to an evaluation method and an evaluation system for evaluating the surface of a structure, such as the state of damage occurring on the surface of the structure and the displacement of the surface.

Conventionally, in order to understand the state of deterioration of concrete that constitutes a structure, a load test using a concrete test piece has been conducted. Techniques for specifying cracks that have occurred in test specimens through this force application experiment are being studied (see, for example, Patent Document 1). In the crack detection method described in this document, the raw image data obtained by imaging the surface of a concrete structure is subjected to processing for removing low-frequency components using wavelet transform, so that the surface of the structure with a small spatial change rate is detected. Create binarized image data from which stains and dirt are removed. Then, using this binarized image data, background image data is created by replacing the pixel corresponding to the crack with the average brightness value of the adjacent pixels, and by dividing the original image by this background image data, Remove stains, dirt, or light unevenness and extract only cracks.

Furthermore, in order to grasp the displacement of the surface of the test object, a digital image correlation method is also being studied in which measurement points are formed in a pattern on the surface and the positions of each measurement point before and after deformation are photographed (for example, non-patent literature 1). Non-Patent Literature describes a 3D dynamic deformation measurement system that calculates the strain of a surface from the position of each measurement point that constitutes a pattern formed on the surface before and after deformation.

Conventionally, in order to make it easier to grasp the displacement of the measurement points using such a digital image correlation method, the measurement points were formed in a color that enhances the contrast with the background. Specifically, after the entire surface was painted white, black measurement points were formed thereon.

JP 2006-162477 A

Shintaro Miyashita, "Introduction of New Products and New Technologies: 3D Dynamic Deformation Measurement System ARAMIS Based on Image Correlation Method," edited by Light Metal Welding Association, "Light Metal Welding," Vol. 56 (2018), No. 5, pp 190-193

However, when the pattern of the measurement points is formed in black, it is difficult to grasp the state of damage such as cracks due to this pattern. Specifically, Figs. 5(a) and 5(b) show the left and right portions of the cross-shaped specimen on which the force application experiment was performed. In this test piece, a pattern of black measurement points for deformation measurement is formed on the left portion shown in FIG. 5(a), and a pattern of black measurement points is formed on the right portion shown in FIG. 5(b). It has not been. In this case, cracks should also have occurred in the left portion of FIG. 5(a), but it was difficult to grasp the cracks in FIG. 5(a).

An evaluation method for solving the above-mentioned problems is an evaluation method used to evaluate the surface of a structure, wherein measuring points with color schemes that can identify the damage state occurring on the surface are measured on the surface of the base paint applied to the surface. Above, a specific wavelength range corresponding to the light reflected by the measurement point among the light reflected by the surface by the measurement point paint that has a different reflectance of the illumination light from the base paint. through a band-pass filter that transmits the light of , to generate a first image in which the measurement point before the force is recognizably photographed and a second image in which the measurement point after the force is recognizably photographed, From the first image and the second image, a damage situation can be identified and a displacement mapping diagram showing changes in the positions of the measurement points is generated, and with respect to the surface in the state where the damage situation has occurred, the Observation light different from the illumination light is emitted to generate and output a damage observation image in which the damage state is photographed.

ADVANTAGE OF THE INVENTION According to this invention, the damage condition of a surface and a displacement of a surface can be grasped|ascertained exactly.

Explanatory drawing explaining the system configuration|structure of embodiment. FIG. 2 is an explanatory diagram of a hardware configuration example of the embodiment; 4 is a flowchart for explaining the processing procedure of surface evaluation processing in the embodiment; BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing of the image which image|photographed the surface which the crack produced in embodiment, Comprising: (a) Damage observation image, (b) The image acquired by permeate|transmitting with a band-pass filter. It is explanatory drawing of the surface of the cross-shaped test body which performed the conventional force application experiment, (a) is the left side part of a test body, (b) is the right side part of a test body.

An embodiment embodying an evaluation method and an evaluation system will be described below with reference to FIGS. 1 to 4. FIG. In this embodiment, in a load-applying experiment of a concrete member (test body) used for a column-beam frame, etc., cracks (damage state) on the surface of the test body (structure) and displacement (strain, movement amount, etc.) on the surface ).

The surface F1 of the specimen shown in FIG. 1 shows the state after the force application experiment. A crack C1 is formed on the surface F1.
As shown in FIG. 1, a surface evaluation system 10 as an imaging system of this embodiment includes a monochromatic light source device 11, an imaging device 15, a bandpass filter 16, and an analysis device 20. FIG.

The monochromatic light source device 11 generates monochromatic light and projects it onto the surface of the specimen. In this embodiment, the monochromatic light source device 11 is a blue LED that emits blue light. The blue LED used in the present embodiment has a characteristic of outputting blue light, and particularly outputting blue light with a wavelength of 465 to 470 (nm) strongly.

The photographing device 15 photographs the surface of the specimen according to the range of sensor sensitivity. A bandpass filter 16 is detachably arranged in front of the lens of the photographing device 15 . When the band-pass filter 16 is installed in front of the lens, the imaging device 15 shoots with transmitted light passing through the band-pass filter 16 because the wavelength range passing through the band-pass filter 16 is narrower than the sensor sensitivity range. Generate an image. Also, when the bandpass filter 16 is removed from the front of the lens, the imaging device 15 generates a captured image of the subject illuminated by white light such as a white LED including the wavelength range of visible light.

The bandpass filter 16 is a filter that passes only a predetermined specific wavelength band, and is made of glass, acryl, or the like. In this embodiment, blue light from the monochromatic light source device 11 is reflected by the surface of the specimen, and is used to transmit only this reflected light. Specifically, a bandpass filter 16 that transmits light with a wavelength of 465 to 470 (nm) is used. In this embodiment, by using a band-pass filter 16 that transmits light with a wavelength of 465 to 470 (nm), only the blue light output by the monochromatic light source device 11 is allowed to pass, and is reflected on the surface of the specimen. Identify light.

The analysis device 20 is connected to the imaging device 15 .
(Hardware configuration example)
FIG. 2 is a hardware configuration example of the information processing device H10 that functions as the analysis device 20. As shown in FIG.

The information processing device H10 has a communication device H11, an input device H12, a display device H13, a storage unit H14, and a processor H15. Note that this hardware configuration is an example, and other hardware may be included.

The communication device H11 is an interface that establishes a communication path with another device and executes data transmission/reception, such as a network interface card or a wireless interface.

The input device H12 is a device that receives input from a user or the like, such as a mouse or a keyboard. The display device H13 is a display, a touch panel, or the like that displays various information.

The storage unit H14 is a storage device (for example, the image information storage unit 25 described later) that stores data and various programs for executing various functions of the analysis device 20 . Examples of the storage unit H14 include ROM, RAM, hard disk, and the like.

The processor H15 uses programs and data stored in the storage unit H14 to control each process in the analysis device 20 (for example, a process in the control unit 21 described later). Examples of the processor H15 include, for example, a CPU and an MPU. The processor H15 develops a program stored in a ROM or the like into a RAM and executes various processes corresponding to various processes. For example, when the application program of the analysis device 20 is activated, the processor H15 operates a process for executing each process shown in FIG. 3, which will be described later.

Processor H15 is not limited to performing software processing for all the processing that it itself executes. For example, the processor H15 may include a dedicated hardware circuit (for example, an application specific integrated circuit: ASIC) that performs hardware processing for at least part of the processing performed by the processor H15. That is, the processor H15 is composed of (1) one or more processors that operate according to a computer program (software), (2) one or more dedicated hardware circuits that execute at least part of various processes, or ( and 3) any combination thereof. A processor includes a CPU and memory, such as RAM and ROM, which stores program code or instructions configured to cause the CPU to perform processes. Memory or computer-readable media includes any available media that can be accessed by a general purpose or special purpose computer.

(Function of analysis device 20)
The analysis device 20 shown in FIG. 1 is a computer terminal for measuring and analyzing damage such as surface cracks and surface displacement. The analysis device 20 includes a control section 21 and an image information storage section 25 .

The control unit 21 performs processing (processing including an image acquisition stage, a displacement measurement stage, a measurement output stage, etc.), which will be described later. By executing a surface evaluation program for this purpose, the control unit 21 functions as an image acquisition unit 211 , a displacement measurement unit 212 and a measurement output unit 213 .

The image acquisition unit 211 acquires images from the imaging device 15 .
In order to evaluate the displacement on the surface, the displacement measuring unit 212 measures the positional change (displacement) of the measurement points M1 arranged in a random pattern formed on the surface.
The measurement output unit 213 outputs the surface displacement and the crack position measured based on the images taken before and after the force application experiment.

The image information storage unit 25 stores images captured by the imaging device 15 . In this embodiment, a damage observation image and a displacement measurement image are stored. A damage observation image is an image captured with white light, and is an image in which cracks occurring on the surface can be observed. The displacement measurement images are images captured using the bandpass filter 16, and include a first image captured before the experiment and a second image captured after the experiment.

<Surface evaluation treatment>
Next, surface evaluation processing will be described with reference to FIGS. 1, 3 and 4. FIG. The surface evaluation process of the present embodiment includes a preparation process executed before conducting a force application experiment on a specimen, and a measurement process executed after a force application experiment is conducted.

First, a base paint is applied to the entire surface of the test piece to be measured (step S1-1). In this embodiment, a white general-purpose water-based paint is used as the base paint.
After the base paint dries, measurement points are formed on the base paint with fluorescent paint (step S1-2). In this embodiment, the measurement points M1 are formed in a random pattern using "Water-based Fluorescent Paint Fluorescent Yellow" manufactured by Komatsu Process Co., Ltd. FIG. This random pattern is a pattern in which measurement points M1 having a plurality of shapes and sizes are randomly arranged. Although the paint that forms this random pattern is special, the pattern shape and arrangement can be the same as those used in normal force-applying experiments. In this embodiment, the measurement points M1 are randomly drawn on the base paint by handwriting.

Then, the control unit 21 of the analysis device 20 executes the photographing recording process before the random pattern test (step S1-3). Specifically, the monochromatic light source device 11 illuminates the surface F1 of the specimen with blue light. Then, the photographing device 15 photographs the surface F1 of the specimen.

In this case, the imaging device 15 generates the first image with light reflected on the surface F<b>1 and transmitted through the bandpass filter 16 . In this embodiment, blue light is reflected by the white base, and blue light is absorbed by each measurement point formed of yellow fluorescent paint. Therefore, the imaging device 15 generates an image in which the brightness of the portion corresponding to the background is high (bright) and the brightness of the portion corresponding to each measurement point is low (dark) via the band-pass filter 16 .

The imaging device 15 then transmits the generated first image to the control unit 21 of the analysis device 20 . The image acquisition section 211 of the control section 21 records the acquired first image in the image information storage section 25 .
After that, a force application experiment is performed in the same manner as in the conventional art.

When the force application experiment is completed, the control unit 21 of the analysis device 20 executes crack photographing recording processing (step S2-1). Specifically, the band-pass filter 16 is removed from the front of the lens of the photographing device 15, and the surface F1 of the specimen is photographed with white illumination light. Then, the image captured by the imaging device 15 is stored in the image information storage unit 25 as a damage observation image.

FIG. 4(a) shows a damage observation image taken with white light. In this image, each measurement point is formed on the surface F1 with a yellow fluorescent paint. Under white light, the base paint on the surface of the specimen and each measurement point (yellow) have high brightness, but the cracks are black and have low brightness. Therefore, the measurement points of the random pattern are inconspicuous with respect to the base paint, and cracks occurring on the surface can be clearly identified.

Next, the control unit 21 of the analysis device 20 executes the photographing recording process after the random pattern test (step S2-2). Specifically, in the same manner as in the photographing and recording process before the random pattern test, blue light is projected from the monochromatic light source device 11 onto the surface F1 of the test object, and the band-pass filter 16 is attached to the surface F1 of the test object. The photographing device 15 is used for photographing. Then, the image acquisition unit 211 of the control unit 21 of the analysis device 20 acquires the second image from the imaging device 15 and records it in the image information storage unit 25 .

FIG. 4(b) shows the second image. In this image, each measurement point formed with fluorescent paint on the surface F1 of the specimen can be recognized.
Next, the control unit 21 of the analysis device 20 executes displacement measurement processing by image comparison (step S2-3). Specifically, the displacement measurement section 212 of the control section 21 acquires the first image and the second image from the image information storage section 25 . Then, the displacement measurement unit 212 identifies the same corresponding measurement points in the first image and the second image, and generates a displacement mapping diagram showing changes (displacements) in the positions of the identified measurement points.

Then, the control unit 21 of the analysis device 20 executes test result output processing (step S2-4). Specifically, the measurement output unit 213 of the control unit 21 acquires the damage observation image from the image information storage unit 25 and identifies the position of the crack included in this image. Then, the measurement output unit 213 outputs the displacement mapping map generated in step S2-3 and the damage observation image specifying the position of the crack to the display device. In this case, the surface position of the test object in the damage observation image and the surface position of the test object in the displacement mapping diagram are aligned and output based on the shape of the test object in the image and the imaging position of the imaging device 15 . good too.

According to this embodiment, the following effects can be obtained.
(1) In the present embodiment, each measurement point M1 is formed on the surface F1 of the test piece and has a color scheme that can be distinguished from the crack C1 that occurs on the surface F1 of the test piece. Each measurement point M1 is formed so as to be identifiable from the base of the surface F1 when photographed through the bandpass filter 16 . Then, the first image and the second image before and after the force application experiment are compared to specify and output the displacement of the surface of the specimen. As a result, it is possible to compare and grasp the state of damage such as cracks occurring on the surface and the displacement of the surface of the specimen specified based on each measurement point M1.

(2) In this embodiment, the surface F1 of the specimen is coated with a white base paint that reflects blue light, and each measurement point M1 is formed thereon with a yellow fluorescent paint that absorbs blue light. As a result, the yellow fluorescent paint forming each measurement point M1 and the white background have a different brightness than the black crack C1, so the crack C1 can be easily recognized for each measurement point M1.

(3) In the present embodiment, when obtaining the first image and the second image, the monochromatic light source device 11 projects blue light onto the surface F1 of the specimen. Blue is in the complementary color of yellow and orange with high lightness and in the vicinity thereof in the color wheel. Yellow or orange colors, which are easy to distinguish from cracks with low brightness, can be used as measurement points, and cracks can be easily detected in visible light. In addition, by using monochromatic light and the bandpass filter 16 corresponding to the wavelength of this monochromatic light, the influence of the environment can be reduced, and the position of the measurement point M1 can be clearly specified. Note that when monochromatic light other than blue (for example, red light or green light) is used, the complementary color of this monochromatic light and colors in the vicinity thereof are colors with low lightness (dark colors). For this reason, when each measurement point is formed with a complementary color of monochromatic light, it becomes difficult to identify cracks. Moreover, when light other than monochromatic light is used, since this light includes a wide range of wavelengths, the light of the frequency components that pass through the band-pass filter becomes weak, making it difficult to distinguish each measurement point.

(4) In this embodiment, the control unit 21 of the analysis device 20 acquires the first image and the second image captured through the bandpass filter 16 that transmits only blue light. Fluorescence (reflected light) from each measurement point M1 formed with yellow fluorescent paint does not pass through the band-pass filter 16. Therefore, in the first image and the second image, the portion corresponding to each measurement point M1 is black. Become. Therefore, by using the bandpass filter 16, the contrast between each measurement point M1 and the white background can be clarified, and the position of each measurement point can be clearly grasped. If there is no band-pass filter 16, the photographing device 15 receives fluorescence (reflected light) from each measurement point, so the portion corresponding to each measurement point M1 does not turn black.

(5) In the present embodiment, the control unit 21 of the analysis device 20 uses the first image and the second image to generate a displacement mapping diagram regarding the displacement of the surface of the specimen and a damage observation image specifying the position of the crack. Output. Thereby, it is possible to grasp the positional relationship between the displacement of the surface F1 of the specimen and the crack C1.

This embodiment can be implemented with the following modifications. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
In the above embodiment, the surface F1 of the specimen is coated with a white base paint that reflects blue light from the monochromatic light source device 11, and yellow fluorescent paint that absorbs blue light is applied on the base paint for each measurement. A bandpass filter 16 that forms a point and transmits only blue light was used. The color, material, and characteristics of the band-pass filter, etc., forming measurement points with a coloring that can be distinguished from the damage status, are not limited to these.

For example, when irradiating blue light, applying a white base paint to the surface, and using a band-pass filter that transmits only blue light, each measurement point is formed using yellow and orange reflective paint. You may Specifically, “Bright Code N Type” “yellow” or “orange” manufactured by Komatsu Process Co., Ltd. may be used. Alternatively, a yellow-green paint may be used. Furthermore, these may be mixed and used.

Alternatively, the base may be coated with the paint used for the measurement points in the embodiment (paint that absorbs the irradiation light), and the measurement points may be formed with the white paint (or reflective paint) used for the base in the embodiment. . In this case, when each measurement point is formed with a yellow fluorescent paint and blue light is irradiated, blue or sky blue with high brightness may be used as the base.
Furthermore, the band-pass filter is not limited to a filter that transmits light in a specific wavelength range that reflects the illumination light reflected by the white base paint. A band-pass filter that matches the wavelength of light to be passed and the range of sensor sensitivity of the imaging device 15 is used. For example, a band-pass filter that passes light (fluorescence) emitted upon receiving illumination light may be used.

- In the above embodiment, the control unit 21 of the analysis device 20 outputs the damage observation image to the display device together with the displacement mapping diagram based on the first image and the second image. The control unit 21 is not limited to outputting the damage observation image, and may output only the displacement mapping diagram. In this case, the damage may be visually recognized. Also, during the force application experiment, the displacement mapping diagram and the damage observation image may be obtained periodically to grasp the time-series changes in the force application experiment.

- In the above embodiment, the measurement points on the surface are formed in a random pattern. A plurality of measurement points used for measurement are not limited to being formed in a random pattern, and may be formed in a regular pattern. Further, the measurement points are not limited to being formed by hand, and may be formed using a patterned roller or the like. In addition, the number of measurement points may be one or two as long as the displacement of the surface can be grasped without forming a pattern.

- In the above embodiment, the surface displacement and damage condition of the test body on which the force application experiment was performed were grasped. A structure whose surface is to be evaluated is not limited to a specimen. For example, images of an actual structure such as a building may be acquired before and after force is applied (first image and second image) to grasp surface displacement and damage conditions.
- In the above embodiment, a concrete specimen was used as the structure. The surface of the structure to be measured is not limited to concrete, and may be, for example, the surface of a structure composed of metal such as steel frame, synthetic resin such as plastic, or wood.

- In the above-described embodiment, the photographing device 15 is used to generate the damage observation image of the crack and the first and second images of the random pattern of the measurement points. The damage observation image and the first and second images may be generated using separate imaging devices. In this case, the surface position of the structure in the damage observation image may be associated with the surface position of the structure in the first and second images based on the imaging position of each imaging device and the shape of the structure. .
- In the above-described embodiment, the imaging device 15 with the detachable band-pass filter 16 was used to photograph the random pattern of the measurement points. The imaging device that captures the random pattern of measurement points is not limited to an imaging device with a detachable bandpass filter, and an imaging device with a fixed bandpass filter that cannot be detached may be used. For example, a photographing device may be used in which the surface of the element of the photosensitive section is specially processed to transmit only a specific wavelength.
Also, as a photographing device for photographing cracks and measurement points, a stereo camera may be used to photograph images.

Next, technical ideas that can be grasped from the above-described embodiment and another example will be added below together with their effects.
(a) The base paint is a white paint or a reflective paint, the measuring point paint is a fluorescent yellow paint or a yellow reflective paint, and the filter reflects blue irradiation light. 3. The photographing method according to claim 1, wherein the band-pass filter transmits light.
As a result, the yellow color forming the measurement points has a weak contrast with respect to the color of the base, so that cracks can be easily recognized.

(b) a first image captured before applying force to the structure by the imaging method according to claim 1, 2 or (a); and the imaging method according to claim 1, 2 or (a). A surface evaluation method, wherein the displacement of the structure is specified by comparing with a second image obtained by photographing a state in which the damage situation occurs after the force is applied.
As a result, it is possible to compare and grasp the state of damage such as cracks occurring on the surface and the displacement of the surface specified based on the positions of the measurement points before and after the force is applied.

(c) The control unit irradiates the structure in which the damage situation has occurred with observation light different from the irradiation light, and specifies and outputs the damage situation. The imaging system according to claim 3.
As a result, it is possible to output the damage condition of the surface together with the displacement of the surface.

C1...Crack F1...Surface M1...Measurement point 10...Surface evaluation system 11...Monochromatic light source device 15...Photographing device 16...Bandpass filter 20...Analyzer 21...Control unit 25...Image Information storage unit 211... Image acquisition unit 212... Displacement measurement unit 213... Measurement output unit.

Claims (3)

An evaluation method used to evaluate the surface of a structure,
A measurement point with a color scheme that enables identification of the damage state occurring on the surface is formed on the base paint applied to the surface with a measurement point paint that has a different reflectance of illumination light from the base paint,
Through a band-pass filter that transmits light in a specific wavelength range corresponding to the light reflected by the measurement point among the light reflected by the surface by the illumination light, the measurement point before force application can be recognized. Generating a photographed first image and a second image photographed so that the measurement point after applying force can be recognized,
From the first image and the second image, a damage situation can be identified and a displacement mapping diagram showing changes in the positions of the measurement points is generated;
An evaluation method, comprising: irradiating observation light different from the illumination light onto the surface in which the damage state has occurred, and generating and outputting a damage observation image in which the damage state is photographed. An evaluation system comprising a control unit for evaluating a surface of a structure,
A measurement point with a color scheme that enables identification of the damage state occurring on the surface is formed on the base paint applied to the surface with a measurement point paint that has a different reflectance of illumination light from the base paint,
The control unit
Through a band-pass filter that transmits light in a specific wavelength range corresponding to the light reflected by the measurement point among the light reflected by the surface by the illumination light, the measurement point before force application is made recognizable. Generating a photographed first image and a second image photographed so that the measurement point after applying force can be recognized,
From the first image and the second image, a damage situation can be identified and a displacement mapping diagram showing changes in the positions of the measurement points is generated;
An evaluation system, comprising: irradiating observation light different from the illumination light onto the surface in which the damage state has occurred, and generating and outputting a damage observation image in which the damage state is photographed. 3. The evaluation system according to claim 2, wherein the control unit outputs the damage observation image after aligning it with the displacement mapping diagram at the surface position of the structure.

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