Reinforced concrete structure evaluation device, method, and program

Abstract

To accurately evaluate the deterioration and damage condition of a reinforced concrete structure by using an image of reflection wave intensity.SOLUTION: An acquisition unit 32 acquires a planar image group for each of multiple depths which includes planar images of reflection wave intensity for a reinforced concrete structure in which multiple reinforcing-bars extending in a first direction are arranged at predetermined intervals along a second direction orthogonal to the first direction. A selection unit 36 selects the depth of the planar image to be used for evaluation for each region on the basis of a statistical index calculated from pixel values of pixels included in each of the regions obtained by dividing the planar image into the multiple regions including one or more pixels. A calculation unit 38 calculates an evaluation value representing a change in the pixel value in the second direction of a composite image obtained by combining portions of the planar images corresponding to the selected depth for each region. An evaluation unit 40 evaluates the deterioration and damage condition of the reinforced concrete structure on the basis of the calculated evaluation value.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a reinforced concrete structure evaluation device, a reinforced concrete structure evaluation method, and a reinforced concrete structure evaluation program. [Background technology]

[0002] Conventionally, the deterioration and damage state of the inside of a reinforced concrete structure has been quantitatively evaluated. For example, a reinforced concrete structure evaluation device has been proposed that acquires a reflected wave intensity image in which the intensity of the reflected wave of an electromagnetic wave irradiated from the surface toward the inside of the reinforced concrete structure at each position on the surface of the reinforced concrete structure is expressed by the pixel value of the pixel corresponding to each position. This device sets a range to be evaluated in the acquired reflected wave intensity image, calculates a type of statistical index corresponding to the set range for the pixel values ​​in the reflected wave intensity image, and evaluates the deterioration and damage state of the reinforced concrete structure using the calculated value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-139748 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above conventional technology, the deterioration and damage of a reinforced concrete structure is evaluated using the variance of the reflected wave intensity image, but there is a problem that the level of the variance calculated as the evaluation value does not necessarily match the deterioration and damage level depending on how the range of the evaluation target is taken. For example, in the above conventional technology, if the variance within the range of the evaluation target is high, it is evaluated as healthy, and if the variance is low, it is evaluated as deteriorated. However, if a part of the range of the evaluation target, which is a deteriorated part that is originally low in variance, includes a part with a large pixel value, the variance becomes high, and the range of the evaluation target may be evaluated as healthy.

[0005] The present invention has been made in consideration of the above-mentioned points, and aims to provide a reinforced concrete structure evaluation device, method, and program that can accurately evaluate the degree of deterioration and damage of reinforced concrete structures using images of reflected wave intensity. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the reinforced concrete structure evaluation device of the present invention includes an acquisition unit that acquires a group of planar images for each of a plurality of depths of the reinforced concrete structure, the planar images representing the intensity of reflected waves of electromagnetic waves irradiated from the surface toward the interior of the reinforced concrete structure at each position on the surface of the reinforced concrete structure in which a plurality of reinforcing bars extending in a first direction are arranged at a predetermined interval along a second direction perpendicular to the first direction, the reflected waves being represented by pixel values ​​of pixels corresponding to each position; a selection unit that divides the planar image into a plurality of regions containing one or more pixels, and selects the depth of the planar image to be used for evaluation for each region based on a statistical index calculated from the pixel values ​​of the pixels included in each of the regions; a calculation unit that calculates an evaluation value representing the change in pixel values ​​in the second direction of a combined image obtained by combining parts of the planar image corresponding to the depths selected by the selection unit for each region; and an evaluation unit that evaluates the degree of deterioration and damage of the reinforced concrete structure based on the evaluation value calculated by the calculation unit.

[0007] Further, a method for evaluating a reinforced concrete structure according to the present invention is a method for evaluating a reinforced concrete structure executed by a reinforced concrete structure evaluation device including an acquisition unit, a selection unit, a calculation unit, and an evaluation unit, in which the acquisition unit acquires a planar image in which the intensity of a reflected wave of an electromagnetic wave irradiated from a surface of a reinforced concrete structure in a direction toward the inside of the reinforced concrete structure at each position on the surface of the reinforced concrete structure in which a plurality of reinforcing bars extending in a first direction are arranged at predetermined intervals along a second direction perpendicular to the first direction, the planar image being represented by pixel values ​​of pixels corresponding to the each position, and a selection unit divides the planar images into a plurality of regions containing one or more pixels, and based on a statistical index calculated from pixel values ​​of pixels contained in each of the regions, selects the depth of the planar image to be used for evaluation for each of the regions; a calculation unit calculates an evaluation value representing the change in pixel values ​​in the second direction of a combined image obtained by combining parts of the planar images corresponding to the depths selected by the selection unit for each region; and an evaluation unit evaluates the degree of deterioration and damage of the reinforced concrete structure based on the evaluation value calculated by the calculation unit.

[0008] In addition, the reinforced concrete structure evaluation program of the present invention is a program for causing a computer to function as an acquisition unit that acquires a group of planar images for each of multiple depths of the reinforced concrete structure, the planar images representing the intensity of reflected waves of electromagnetic waves irradiated from the surface of a reinforced concrete structure in a direction toward the interior of the reinforced concrete structure at each position on the surface of the reinforced concrete structure, the reflected waves being represented by pixel values ​​of pixels corresponding to each position; a selection unit that divides the planar image into multiple regions containing one or more pixels, and selects the depth of the planar image to be used for evaluation for each region based on a statistical index calculated from the pixel values ​​of the pixels included in each of the regions; a calculation unit that calculates an evaluation value that represents the change in pixel values ​​in the second direction of a combined image obtained by combining parts of the planar image corresponding to the depths selected by the selection unit for each region; and an evaluation unit that evaluates the degree of deterioration and damage of the reinforced concrete structure based on the evaluation value calculated by the calculation unit. Effect of the Invention

[0009] According to the reinforced concrete structure evaluation device, method, and program of the present invention, the degree of deterioration and damage of a reinforced concrete structure can be accurately evaluated using an image of reflected wave intensity. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of a reinforced concrete structure evaluation system. [Diagram 2] 11 is a diagram for explaining detection of a reflected response waveform. FIG. [Diagram 3] FIG. 13 is a diagram showing an example of a reflected response waveform detected for one detection point. [Figure 4] FIG. 11 is a diagram for explaining three-dimensional reflected wave intensity. [Diagram 5] 1 is a block diagram showing a hardware configuration of a reinforced concrete structure evaluation device. [Figure 6]1 is a block diagram showing an example of a functional configuration of a reinforced concrete structure evaluation device. [Figure 7] FIG. 2 is a diagram for explaining a planar image group. [Figure 8] FIG. 11 is a diagram for explaining calculation of wavelet transform coefficients. [Figure 9] FIG. 13 is a diagram for explaining extraction of an evaluation target region. [Figure 10] FIG. 13 is a diagram for explaining extraction of an evaluation target region. [Figure 11] FIG. 13 is a diagram for explaining extraction of an evaluation target region. [Figure 12] FIG. 11 is a diagram for explaining calculation of clarity. [Figure 13] 13 is a diagram for explaining generation of a graph showing the relationship between a representative value of clarity and depth. FIG. [Figure 14] FIG. 13 is a diagram for explaining selection of depth for each grid. [Figure 15] FIG. 13 is a diagram for explaining selection of depth for each grid. [Figure 16] FIG. 13 is a diagram for explaining generation of a patchwork image. [Figure 17] FIG. 13 is a diagram for explaining expansion of a patchwork image. [Figure 18] FIG. 13 is a diagram for explaining expansion of a patchwork image. [Figure 19] 5A to 5C are diagrams for explaining evaluation values ​​and evaluation images in the first embodiment. [Figure 20] 13 is a flowchart showing the flow of a reinforced concrete structure evaluation process. [Figure 21] FIG. 2 is a diagram for explaining an example of a mother wavelet used in wavelet transformation. [Figure 22] FIG. 11 is a diagram for explaining calculation of an evaluation value in the second embodiment. [Diagram 23] FIG. 11 is a diagram for explaining calculation of an evaluation value in the second embodiment. [Figure 24] FIG. 11 is a diagram for explaining an evaluation result in the second embodiment. [Diagram 25]FIG. 11 is a diagram for explaining another example of calculation of an evaluation value in the second embodiment. [Figure 26] FIG. 11 is a diagram for explaining another example of calculation of an evaluation value in the second embodiment. [Figure 27] FIG. 11 is a diagram for explaining an evaluation result in the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

[0012] In the following embodiments, a case will be described in which the deterioration and damage state inside a reinforced concrete deck, which is a road surface structure, is evaluated. In the reinforced concrete deck, in one or more layers, a plurality of reinforcing bars extending in a first direction are arranged at a predetermined interval along a second direction perpendicular to the first direction. In other words, the second direction is the direction in which the presence and absence of reinforcing bars alternate.

[0013] First Embodiment As shown in FIG. 1, the reinforced concrete structure evaluation system 100 according to the first embodiment includes a reinforced concrete structure evaluation device 10, an electromagnetic wave device 50, and an image processing device 60.

[0014] The electromagnetic wave device 50 includes a plurality of electromagnetic wave emitting units and receiving units provided on a line. The electromagnetic wave device 50 is provided, for example, on the rear lower portion of the vehicle 90 so that the line direction of the electromagnetic wave device 50 is the width direction of the road, and the traveling direction of the vehicle 90 is a direction perpendicular to the width direction of the road (hereinafter referred to as the "axial direction"). The width direction corresponds to the above-mentioned first direction, and the axial direction corresponds to the above-mentioned second direction.

[0015] As shown in Fig. 2, the electromagnetic wave device 50 scans a reflected wave intensity detection range 95 on the road surface in the vehicle travel direction, irradiates electromagnetic waves from the surface toward the inside (depth) of the reinforced concrete floor slab, and receives the reflected waves. This detects the reflected wave intensity according to the depth for each position in the reflected wave intensity detection range 95. The reflected wave intensity according to the depth is detected for each position (hereinafter referred to as a "detection point") in the form of a reflected response waveform as shown in Fig. 3. One detection point may be, for example, 1 cm x 1 cm, and one line width may be 2.0 m. In this case, reflected response waveforms for 200 detection points are detected for one line.

[0016] The depth corresponds to the time from the emission of the electromagnetic wave to the reception of the reflected wave. The reflected wave intensity for each depth of the reinforced concrete deck can be obtained by extracting the reflected wave intensity corresponding to each desired depth from the reflected response waveform as shown in Figure 3. That is, the reflected wave waveform is detected for each detection point set two-dimensionally on the road surface, and multiple reflected wave intensity values ​​are obtained in the depth direction from the detected reflected response waveform, thereby obtaining three-dimensional reflected wave intensity in the reflected wave intensity detection range 95.

[0017] The electromagnetic wave device 50 outputs to the image processing device 60 information on the acquired reflected response waveform (reflected wave intensity according to depth) for each detection point.

[0018] The electromagnetic wave device 50 is not limited to being attached to the vehicle 90, but may be in other forms such as being held by a worker or being in the form of a handcart.

[0019] As described above, the information on the reflected response waveforms at each detection point output from the electromagnetic wave device 50 represents three-dimensional reflected wave intensity. Therefore, as shown in FIG. 4, the image processing device 60 acquires information on the reflected wave intensity as planar data of the reflected wave intensity according to the depth direction, longitudinal data of the reflected wave intensity along the axial direction, and transverse data along the width direction. Based on the acquired information, the image processing device 60 extracts the reflected wave intensity for each depth, converts the reflected wave intensity into pixel values, and performs planar combination processing on the pixels corresponding to each detection point to generate a planar image of the reflected wave intensity for each depth. The image processing device 60 outputs a group of planar images of the reflected wave intensity for each depth that it has generated to the reinforced concrete structure evaluation device 10.

[0020] In this embodiment, an example will be described in which the reinforced concrete structure evaluation device 10 and the image processing device 60 are mounted on the vehicle 90, but the present invention is not limited to this. The reinforced concrete structure evaluation device 10 and the image processing device 60 may be provided outside the vehicle, and information on the reflected response waveform acquired by the electromagnetic wave device 50 (details will be described later) may be transmitted from the electromagnetic wave device 50 to the image processing device 60.

[0021] Fig. 5 is a block diagram showing a hardware configuration of the reinforced concrete structure evaluation device 10 according to the first embodiment. As shown in Fig. 5, the reinforced concrete structure evaluation device 10 has a CPU (Central Processing Unit) 12, a memory 14, a storage device 16, an input device 18, an output device 20, a storage medium reading device 22, and a communication I / F (Interface) 24. Each component is connected to each other via a bus 26 so as to be able to communicate with each other.

[0022] The storage device 16 stores a reinforced concrete structure evaluation program for executing a reinforced concrete structure evaluation process described below. The CPU 12 is a central processing unit, and executes various programs and controls each component. That is, the CPU 12 reads the program from the storage device 16 and executes the program using the memory 14 as a working area. The CPU 12 controls each of the components and performs various calculation processes according to the program stored in the storage device 16.

[0023] The memory 14 is made up of a RAM (Random Access Memory) and serves as a working area to temporarily store programs and data. The storage device 16 is made up of a ROM (Read Only Memory), a HDD (Hard Disk Drive), a SSD (Solid State Drive), etc., and stores various programs including an operating system and various data.

[0024] The input device 18 is a device for performing various inputs, such as a keyboard, a mouse, etc. The output device 20 is a device for outputting various information, such as a display, a printer, etc. A touch panel display may be used as the output device 20 to function as the input device 18.

[0025] The storage medium reader 22 reads data stored in various storage media such as CD (Compact Disc)-ROM, DVD (Digital Versatile Disc)-ROM, Blu-ray disc, USB (Universal Serial Bus) memory, etc., and writes data to the storage media. The communication I / F 24 is an interface for communicating with other devices, and uses standards such as Ethernet (registered trademark), FDDI, or Wi-Fi (registered trademark).

[0026] Next, the functional configuration of the reinforced concrete structure evaluation device 10 according to the first embodiment will be described.

[0027] Fig. 6 is a block diagram showing an example of the functional configuration of the reinforced concrete structure evaluation device 10. As shown in Fig. 6, the functional configuration of the reinforced concrete structure evaluation device 10 includes an acquisition unit 32, an extraction unit 34, a selection unit 36, a calculation unit 38, and an evaluation unit 40. Each functional configuration is realized by the CPU 12 reading out the reinforced concrete structure evaluation program stored in the storage device 16, expanding it in the memory 14, and executing it.

[0028] The acquisition unit 32 acquires a group of planar images of reflected wave intensity for each depth output from the image processing device 60. The acquisition unit 32 transfers the group of planar images as shown in the upper diagram of Fig. 7 to the extraction unit 34 as information of a three-dimensional array in which the planar coordinates of pixels corresponding to the same position in the planar images of each depth are unified as shown in the lower diagram of Fig. 7. Note that in the planar image in the upper diagram of Fig. 7, the horizontal direction on the paper is the axial direction, and the vertical direction on the paper is the width direction. In the following diagrams, unless otherwise specified, the long direction of each image is the axial direction, and the short direction is the width direction.

[0029] The extraction unit 34 detects joints of the reinforced concrete floor slabs from each of the planar images acquired by the acquisition unit 32, and extracts the detected joints as an evaluation target area. Specifically, the extraction unit 34 generates a full-layer overlay image by taking the sum or average in the depth direction of pixel values ​​of pixels with the same planar coordinates. As shown in Fig. 8, the extraction unit 34 calculates a wavelet transform coefficient for each pixel for each axial line (dashed line portion in the upper diagram of Fig. 8) of the full-layer overlay image. Then, the extraction unit 34 generates a wavelet transform result by mapping the calculated wavelet transform coefficient to each pixel.

[0030] As shown in FIG. 9, the extraction unit 34 calculates the sum of wavelet transform coefficients for each column of the wavelet transform result, and identifies the maximum value of the sum. In FIG. 9, the wavelet transform coefficients are expressed by simplified numerical values ​​for ease of explanation. The extraction unit 34 shifts the pixel positions of each row by a predetermined value in the axial direction, and calculates the sum of wavelet transform coefficients for each column of the shifted wavelet transform result. As shown in FIG. 10, the extraction unit 34 detects the shift amount that maximizes the maximum value in the relationship between the shift amount and the maximum value of the sum of wavelet transform coefficients for each column. Then, as shown in FIG. 11, the extraction unit 34 identifies joint parts based on the columns (columns indicated by L and R in FIG. 11) that maximize the sum for the detected shift amount and the shift amount for each of the left and right ends of the planar image. The extraction unit 34 extracts the space between the identified joint parts as an evaluation target area (white area in the lower diagram of FIG. 11). The shift amount may be different between the left and right ends of the evaluation target area.

[0031] The selection unit 36 ​​selects the depth of the planar image to be used for evaluation for each region based on a statistical index calculated from pixel values ​​of pixels included in each of the regions obtained by dividing the evaluation target region of the planar image into a plurality of regions each including one or more pixels. In the first embodiment, as an example, when the evaluation target region of the planar image is divided into a grid shape, each grid is regarded as the above-mentioned region. In the first embodiment, a wavelet transform coefficient calculated based on pixel values ​​of pixels included in the grid is used as the statistical index.

[0032] A specific description will be given with reference to Fig. 12. In Fig. 12, the upper rows of each of (A) to (E) show planar images or images onto which calculated values ​​are mapped, and the lower rows show pixel values ​​or calculated values ​​of each pixel of an axial line shown by a solid line in each image shown in the upper row.

[0033] The selection unit 36 ​​calculates a wavelet transform coefficient for each pixel as shown in FIG. 12B for each line in the axial direction of the planar image as shown in FIG. 12A. The mother wavelet used to calculate the wavelet transform coefficient may have any shape, such as a general shape or a Mexican hat shape. If the range of pixel values ​​of the planar image is 0 to x (e.g., 0 to 100), the range of the wavelet transform coefficient is -x to x (e.g., -100 to 100). The selection unit 36 ​​calculates the square value of the calculated wavelet transform coefficient as shown in FIG. 12C. The range of the square value is 0 to x 2 (For example, 0 to 10000). The squared value is calculated in order to detect both downward and upward convex peaks in the detection of peaks, which will be described later. The selection unit 36 ​​performs logarithmic transformation on the calculated squared value of the wavelet transform coefficient, as shown in FIG. 12(D). The range of values ​​after logarithmic transformation is 0 to log(x 2 +1) (for example, 0 to 10). The selection unit 36 ​​also calculates a value (hereinafter referred to as "clarity") by performing Gaussian filter processing on the logarithmic transformed value, as shown in FIG. 12(E). The clarity range is 0 to log(x + 1) like the logarithmic transformed value. 2 +1), but the range may be narrowed by smoothing out the peaks of the waveform (for example, 0 to 6). Note that Gaussian filtering is an example of waveform smoothing processing, and instead of the Gaussian filter, a mean filter, a low-pass filter in Fourier transform, or the like may be applied.

[0034] The selection unit 36 ​​divides the evaluation target area of ​​the planar image into grids of, for example, 15 pixels vertical by 15 pixels horizontal, and calculates a representative value of clarity within each grid. The representative value may be, for example, an average value or a median value of clarity within the grid. The selection unit 36 ​​generates a graph showing the relationship between the representative value of clarity and the depth in grids having the same planar coordinates in the planar image for each depth. The selection unit 36 ​​also performs Gaussian filter processing on the generated graph. FIG. 13 shows an example of a graph generated for a certain grid (a grid shown in a thick frame in the upper diagram of FIG. 13). The upper diagram of FIG. 13 shows the clarity of each of the depths (a), (b), (c), and (d), the lower left diagram of FIG. 13 shows a graph showing the relationship between the representative value of clarity for the grid and the depth, and the lower right diagram of FIG. 13 shows the result of performing Gaussian filter processing on the graph.

[0035] The selection unit 36 ​​detects the maximum value of the graph obtained by performing Gaussian filter processing on the relationship between the representative value of clarity and the depth as a peak. When a reinforced concrete floor slab has multiple layers of reinforcing bars, the selection unit 36 ​​detects the same number of peaks as the number of layers of reinforcing bars. In the first embodiment, a case in which two peaks corresponding to upper and lower reinforcing bars are detected will be described. In this case, the selection unit 36 ​​detects two peaks in descending order of clarity value, as shown in the lower right diagram of FIG. 13.

[0036] As shown in FIG. 14A, the selection unit 36 ​​plots the peaks detected for all grids in a three-dimensional space of the depth corresponding to the peak, the axial position of the grid, and the width position of the grid to obtain the distribution of the peaks. From the distribution of the peaks, the selection unit 36 ​​generates a histogram of the number of peaks detected against the depth, as shown in FIG. 14B, and determines a range (shaded portion) corresponding to the upper reinforcing bar and a range (shaded portion) corresponding to the lower reinforcing bar from the shape of the histogram. For example, the selection unit 36 ​​determines the range in which the total number of peaks detected corresponding to each depth included in the predetermined range is the largest as the range corresponding to the upper reinforcing bar, and the range in which the second largest total is the range corresponding to the lower reinforcing bar. Note that depths that do not correspond to the depth where the reinforcing bar exists, for example, depths near the road surface, are excluded from the range for determining the range.

[0037] As shown in (C) to (F) of Figures 14, the selection unit 36 ​​selects the average of the depths within the range corresponding to the determined upper reinforcing bar and the range corresponding to the lower reinforcing bar in a graph showing the relationship between the representative value of clarity and depth for each grid.

[0038] In Fig. 14(C), the graph showing the relationship between the representative value of clarity and depth shows peaks corresponding to the upper and lower reinforcing bars, but in some grids, no clear peaks exist. Fig. 14(D) shows a case where a peak for the upper reinforcing bar exists but no peak for the lower reinforcing bar exists, (E) shows a case where a peak for the lower reinforcing bar exists but no peak for the upper reinforcing bar exists, and (F) shows a case where neither peak exists.

[0039] Therefore, as shown in FIG. 15, the selection unit 36 ​​arranges the depths selected for each grid for the upper rebar and the lower rebar in association with the plane coordinates of the grid. Note that "x" indicates a grid where no peak exists. For example, the selection unit 36 ​​may determine that no peak exists when the variance of the representative values ​​of clarity corresponding to each depth within the range is equal to or less than a predetermined value. The selection unit 36 ​​interpolates the depths for grids where no peak exists based on the depths around the grid. As a result, the depths for all grids are selected as shown in the lower diagram of FIG. 15.

[0040] The calculation unit 38 generates a patchwork image by combining parts of the planar images at the depths selected by the selection unit 36 ​​for each grid. The patchwork image is an example of a combined image of the present invention. Specifically, as shown in the upper diagram of Fig. 16, the calculation unit 38 uses the depths selected for each grid and the group of planar images to specify the depths selected by the selection unit 36 ​​for each grid, and selects the planar images at the specified depths from the group of planar images at all depths.

[0041] The calculation unit 38 extracts a portion of the selected planar image that corresponds to the grid. As shown in the middle diagram of FIG. 16, the calculation unit 38 generates a patchwork image by combining the portions of the planar image extracted for all grids. In the first embodiment, the depth for the upper reinforcing bar and the depth for the lower reinforcing bar are selected by the selection unit 36, so the calculation unit 38 generates a patchwork image of the upper reinforcing bar and a patchwork image of the lower reinforcing bar as shown in the lower diagram of FIG. 16. Note that the selection is not limited to the case of selecting one planar image corresponding to the specified depth, and a predetermined number of planar images (for example, five) corresponding to each of a predetermined number of depths before and after the specified depth may be selected. In this case, the calculation unit 38 generates a predetermined number of patchwork images.

[0042] The calculation unit 38 calculates an evaluation value using wavelet transform coefficients based on pixel values ​​of pixels in the patchwork image. At this time, the calculation unit 38 may calculate the evaluation value using a patchwork image expanded by adding pixels whose pixel values ​​are interpolated between pixels in the axial direction of the patchwork image.

[0043] Here, the evaluation values ​​in the cases where the patchwork image is expanded and where it is not expanded will be described with reference to Fig. 17. In the example of Fig. 17, it is assumed that the patchwork image includes a deteriorated and damaged portion (portion indicated by a broken line) as shown in the upper diagram of Fig. 17.

[0044] When expansion is performed, for example, the calculation unit 38 calculates an interpolation curve by quadratic spline interpolation or the like for each axial line of the patchwork image based on the pixel values ​​of the patchwork image before expansion, as shown in Fig. 18. The calculation unit 38 sets one or more pixels (marked with x in Fig. 18) to be interpolated between the pixels before expansion (marked with black circles in Fig. 18), and specifies the pixel values ​​of the set pixels from the interpolation curve. The calculation unit 38 adds pixels with the specified pixel values ​​between the pixels before expansion to expand the patchwork image (B in Fig. 17).

[0045] The calculation unit 38 calculates a wavelet transform coefficient for each pixel for each axial line of the expanded patchwork image, similar to the calculation of clarity by the selection unit 36, and squares the calculated wavelet transform coefficient to perform logarithmic transformation. The calculation unit 38 then calculates an evaluation value by performing Gaussian filter processing for each line on the logarithmic transformed value. In addition, when a predetermined number of patchwork images corresponding to each of a predetermined number of depths before and after the identified depth are generated, the calculation unit 38 calculates the above evaluation value for each patchwork image, and the maximum evaluation value in the depth direction of pixels with the same planar coordinates is set as the evaluation value of each pixel of the patchwork image.

[0046] The calculation unit 38 calculates an evaluation value for each pixel of the expanded patchwork image, as shown in C in FIG. 17. In the example of FIG. 17, in the distribution of the evaluation values, the lower the evaluation value, the darker the color of the pixel, and the higher the evaluation value, the lighter the color of the pixel. The calculation unit 38 calculates an evaluation value for each pixel of the expanded patchwork image by thinning out pixels so that the evaluation value corresponding to the expanded patchwork image becomes the size of the patchwork image before expansion, as shown in D in FIG. 17. In the example of FIG. 17, in the reinforced concrete floor slab, for example, there is a part (axial part shown by A in FIG. 17) where the reinforcing bars are dense, such as the girder part of a bridge. As shown in E in FIG. 17, in the case where the patchwork image is not expanded, there are parts where the evaluation value is low in the part where the reinforcing bars are dense, even though it is not a deteriorated damaged part. On the other hand, when the evaluation value is calculated after expanding the patchwork image, the evaluation value is also calculated appropriately for the part where the reinforcing bars are dense.

[0047] The calculation unit 38 may apply mother wavelets of different widths to the patchwork image of the upper reinforcing bar and the patchwork image of the lower reinforcing bar as the mother wavelets to be applied when calculating the wavelet transform coefficients. Specifically, the patchwork image of the lower reinforcing bar is blurrier than the patchwork image of the upper reinforcing bar. Therefore, the width of the mother wavelet applied to the patchwork image of the lower reinforcing bar is made wider than the width of the mother wavelet applied to the patchwork image of the upper reinforcing bar.

[0048] The evaluation unit 40 evaluates the deterioration and damage state of the reinforced concrete floor slab based on the evaluation value calculated by the calculation unit 38. Specifically, the evaluation unit 40 selects a representative value of the evaluation value of each pixel included in each grid of the patchwork image. In order to avoid overlooking deterioration and damage, the representative value may be the lowest evaluation value among the evaluation values ​​in the grid. The evaluation unit 40 evaluates the deterioration and damage state for each grid based on a comparison between the selected representative value of the evaluation value and a predetermined threshold value. The threshold value is set in advance to a value that provides the highest degree of agreement between the area below the threshold value and the correct deterioration and damage location when areas with evaluation values ​​equal to or greater than the threshold value and areas below the threshold value are classified while changing the threshold value in a planar image in which the correct answer for the deterioration and damage state is known.

[0049] Furthermore, the evaluation unit 40 displays an evaluation image in which each grid of the patchwork image is displayed in a display mode according to the evaluation result for each grid. For example, as shown in Fig. 19, the evaluation unit 40 may display an evaluation image in which each grid of the patchwork image is colored according to the representative value of the evaluation values ​​selected for each grid. For example, the evaluation unit 40 may display an evaluation image in which grids for which the representative value of the evaluation values ​​selected for each grid is less than a threshold value are colored.

[0050] Next, the operation of the reinforced concrete structure evaluation system 100 according to the first embodiment will be described.

[0051] The electromagnetic wave device 50 scans a reflected wave intensity detection range 95 on the road surface in the vehicle travel direction, irradiates electromagnetic waves from the surface toward the inside (depth) of the reinforced concrete floor slab, and receives the reflected waves. As a result, the electromagnetic wave device 50 detects the reflected wave intensity corresponding to the depth for each position in the reflected wave intensity detection range 95. The electromagnetic wave device 50 then outputs information on the reflection response waveform (reflected wave intensity corresponding to depth) for each detection point that it has acquired to the image processing device 60.

[0052] Next, the image processing device 60 acquires the information output from the electromagnetic wave device 50, extracts the reflected wave intensity for each depth based on the acquired information, converts the reflected wave intensity into pixel values, performs planar combination processing on the pixels corresponding to each detection point, and generates a group of planar images of the reflected wave intensity for each depth. The image processing device 60 then outputs the generated group of planar images of the reflected wave intensity for each depth to the reinforced concrete structure evaluation device 10.

[0053] The reinforced concrete structure evaluation device 10 executes a reinforced concrete structure evaluation process. Fig. 20 is a flowchart showing the flow of the reinforced concrete structure evaluation process executed by the CPU 12 of the reinforced concrete structure evaluation device 10. The CPU 12 reads out a reinforced concrete structure evaluation program from the storage device 16, deploys it in the memory 14, and executes it. As a result, the CPU 12 functions as each functional component of the reinforced concrete structure evaluation device 10, and the reinforced concrete structure evaluation process shown in Fig. 20 is executed.

[0054] First, in step S10, the acquisition unit 32 acquires a group of planar images of reflected wave intensity for each depth output from the image processing device 60. Then, the acquisition unit 32 transfers the group of planar images to the extraction unit 34 as information of a three-dimensional array in which the planar coordinates of pixels corresponding to the same position in the planar images at each depth are unified.

[0055] Next, in step S12, the extraction unit 34 detects joints of the reinforced concrete structure from each of the planar images passed from the acquisition unit 32, and extracts the area between the detected joints as an evaluation target area.

[0056] Next, in step S14, the selection unit 36 ​​calculates clarity for each grid based on a wavelet transform coefficient calculated from pixel values ​​of pixels included in each grid obtained by dividing the evaluation target area of ​​the planar image into a plurality of grids. The selection unit 36 ​​also generates a graph in which a Gaussian filter process is performed on the relationship between the representative value of clarity and the depth in grids with the same planar coordinates in the planar image for each depth. Then, the selection unit 36 ​​selects the depth of the planar image to be used for evaluation for each grid based on peaks detected from this graph.

[0057] Next, in step S16, the calculation unit 38 generates a patchwork image by combining, for each grid, portions of the planar images at the depths selected by the selection unit 36. The calculation unit 38 also extends the patchwork image by adding pixels with interpolated pixel values ​​between pixels in the axial direction of the patchwork image.

[0058] Next, in step S18, the calculation unit 38 calculates a wavelet transform coefficient for each pixel for each line in the axial direction of the expanded patchwork image, squares the calculated wavelet transform coefficient, and performs logarithmic transformation.The calculation unit 38 then calculates an evaluation value by performing Gaussian filter processing on the logarithmic transformed value for each line, and calculates an evaluation value for each pixel of the expanded patchwork image by thinning out the pixels to the size of the expanded patchwork image.

[0059] Next, in step S20, the evaluation unit 40 selects a representative value of the evaluation values ​​of each pixel included in each grid of the patchwork image, and evaluates the degree of deterioration and damage for each grid based on a comparison between the selected representative value of the evaluation values ​​and a predetermined threshold value. The evaluation unit 40 then displays an evaluation image in which each grid of the patchwork image is displayed in a display mode according to the evaluation result for each grid, and the reinforced concrete structure evaluation process ends.

[0060] As described above, according to the reinforced concrete structure evaluation system of the first embodiment, the reinforced concrete structure evaluation device acquires a group of planar images of reflected wave intensity at each position on the surface of the reinforced concrete structure for each depth. The reinforced concrete structure evaluation device also selects the depth of the planar image to be used for evaluation for each grid based on a statistical index calculated from pixel values ​​of pixels included in each grid obtained by dividing the planar image into a plurality of grids. The reinforced concrete structure evaluation device then calculates an evaluation value using a wavelet transform coefficient based on a combined image obtained by combining parts of the planar images at the depths selected for each grid, and evaluates the deterioration and damage state of the reinforced concrete structure based on the evaluation value. This makes it possible to accurately evaluate the deterioration and damage state of the reinforced concrete structure using the images of reflected wave intensity.

[0061] In the first embodiment, the clarity and evaluation value are calculated by logarithmically transforming the squared values ​​of the wavelet transform coefficients calculated from pixel values ​​and smoothing them as shown in Fig. 12, but the present invention is not limited to this. For example, the clarity or evaluation value may be calculated by taking an envelope of a waveform (corresponding to (B) in Fig. 12) showing the wavelet transform coefficients for one line in the axial direction calculated for each pixel of a planar image or a patchwork image.

[0062] Furthermore, in the first embodiment, the mother wavelet applied when calculating the wavelet transform coefficients may be a mother wavelet (A in FIG. 21) having a width equivalent to the axial width of the reinforcing bar portion in the planar image or patchwork image, as shown in FIG. 21. The mother wavelet may also be a mother wavelet (B in FIG. 21) having a width that reacts to the edge of the reinforcing bar portion in the planar image or patchwork image. These mother wavelets may also be applied selectively.

[0063] <Second embodiment> Next, a second embodiment will be described. In the reinforced concrete structure evaluation system according to the second embodiment, the same components as those in the reinforced concrete structure evaluation system 100 according to the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

[0064] As shown in FIG. 1, a reinforced concrete structure evaluation system 200 according to the second embodiment includes a reinforced concrete structure evaluation device 210, an electromagnetic wave device 50, and an image processing device 60.

[0065] The hardware configuration of the reinforced concrete structure evaluation device 210 according to the second embodiment is similar to the hardware configuration of the reinforced concrete structure evaluation device 10 according to the first embodiment shown in FIG. 5, and therefore will not be described.

[0066] Next, the functional configuration of the reinforced concrete structure evaluation device 210 according to the second embodiment will be described.

[0067] 6, the reinforced concrete structure evaluation device 210 includes, as functional components, an acquisition unit 32, an extraction unit 34, a selection unit 36, a calculation unit 238, and an evaluation unit 240. Each functional component is realized by the CPU 12 reading out a reinforced concrete structure evaluation program stored in the storage device 16, expanding it in the memory 14, and executing it.

[0068] For example, assume that the location indicated by (1) on the line to be processed in the patchwork image shown in Fig. 22 is in a healthy state. In this case, as shown in A in Fig. 22, peaks appear in the change in pixel value (axial position-pixel value) relative to the axial position at the location indicated by (1) on the line to be processed at intervals corresponding to the predetermined intervals at which the rebars are arranged. Thus, a frequency analysis is performed by regarding the axial position as the time axis, and the graph of axial position-pixel value is converted into a frequency distribution (frequency-intensity) as shown in B in Fig. 22. From the frequency distribution, peaks are detected around a specific frequency corresponding to the period of the intervals at which the rebars are arranged.

[0069] On the other hand, the portion indicated by (2) on the line to be processed in the patchwork image shown in FIG. 22 is in a deteriorated state. In this case, as shown in C in FIG. 22, no periodicity of peaks is observed in the graph of axial position vs. pixel value. Therefore, as shown in D in FIG. 22, no peak of a specific frequency is detected in the frequency distribution. Also, in the portion indicated by (3) on the line to be processed in the patchwork image shown in FIG. 22, the pixel values ​​of the reinforcing bar portion that appear periodically and the pixel values ​​of the other reflections are mixed. In this case, the axial position vs. pixel value is as shown in E in FIG. 22. In the frequency distribution obtained by performing frequency analysis on this axial position vs. pixel value, as shown in F in FIG. 22, a specific frequency that appears in the frequency distribution of the healthy portion and a distribution in a frequency region lower than that frequency are observed. Also, the intensity (magnitude of distribution) at a specific frequency is lower than the intensity at a specific frequency in the healthy portion.

[0070] Therefore, the calculation unit 238 calculates, as an evaluation value, a value obtained by performing frequency analysis on the change in pixel value for the pixel position of each pixel along the axial line of the patchwork image. Specifically, the calculation unit 238 creates a graph of axial position-pixel value showing the change in pixel value for the pixel position in each analysis frame while sliding an analysis frame of a predetermined width by a predetermined distance along the axial direction of the patchwork image. Then, as shown in FIG. 23, the calculation unit 238 detects peaks from the graph of axial position-pixel value, and counts the distance between the peaks (number of pixels) as the period of the peak. Furthermore, the calculation unit 238 converts the period into a frequency, for example, in terms of 1 ms per pixel. In this case, for example, when the period is 8 pixels, the frequency is 125 Hz. Then, the calculation unit 238 creates a frequency distribution by voting the converted frequency in a frequency-intensity histogram. The calculation unit 238 detects peaks from the created frequency distribution, and calculates the frequency of the detected peak and the intensity at that frequency as the evaluation value of the range specified in the analysis frame. The calculation unit 238 calculates the evaluation value for each line of the patchwork image by the above processing, and thereby obtains the evaluation value as a planar distribution.

[0071] The evaluation unit 240 evaluates the deterioration and damage state of the reinforced concrete floor slab based on whether or not the frequency indicated by the evaluation value calculated by the calculation unit 238 is included in a predetermined frequency range based on a predetermined frequency. The reference frequency may be a frequency calculated in advance for a healthy portion. For example, the reference frequency is 125 Hz, and the frequency range is 125 Hz ± 10 Hz. In this case, the evaluation unit 240 evaluates the portion as a healthy portion if the frequency of the peak indicated by the evaluation value is within the range of 115 to 135 Hz, and evaluates the portion as a deteriorated portion if it is less than 115 Hz or exceeds 135 Hz. In addition, the evaluation unit 240 may evaluate the portion as tending to deteriorate if the intensity of the frequency is equal to or less than a predetermined value, even if the frequency indicated by the evaluation value is within the predetermined frequency range. Note that the above reference frequency and frequency range are only examples, and an appropriate value may be set according to the interval of the reinforcing bars as an index of evaluation based on the frequency of the peak.

[0072] The evaluation unit 240 expresses the evaluation results for each range of the analysis frame as a planar distribution. Fig. 24 shows an example of the evaluation results for a patchwork image including deteriorated areas (solid line frame in the upper diagram of Fig. 24). In the example of the evaluation results in Fig. 24, healthy areas are expressed in black, deteriorated areas are expressed in white, and areas showing a tendency to deteriorate are expressed in gray. In the example of Fig. 24, the deteriorated areas in the patchwork image and the deteriorated areas indicated by the evaluation results generally coincide with each other.

[0073] Regarding the operation of the reinforced concrete structure evaluation system 200 of the second embodiment, the processing of steps S18 and S20 of the reinforced concrete structure evaluation process (Figure 20) executed by the reinforced concrete structure evaluation device 210 is simply the processing of the calculation unit 238 and evaluation unit 240 described above, so an explanation will be omitted.

[0074] As described above, according to the reinforced concrete structure evaluation system of the second embodiment, the reinforced concrete structure evaluation device calculates a value obtained by performing frequency analysis on the change in pixel value for each pixel position along the line in the second direction of the combined image, and evaluates the deterioration and damage state of the reinforced concrete structure based on the evaluation value. This makes it possible to accurately evaluate the deterioration and damage state of the reinforced concrete structure using the image of the reflected wave intensity.

[0075] In the second embodiment, the expression of healthy and degraded parts in the evaluation results can be adjusted by changing the width of the analysis frame and the slide width for calculating the evaluation value. Specifically, when the width of the analysis frame is widened, a gradation occurs at the boundary between healthy and degraded parts, and when the width of the analysis frame is narrowed, the boundary between healthy and degraded parts becomes clearer. In addition, when the slide width is widened, the resolution of the evaluation results becomes coarse, and when the slide width is narrowed, the resolution of the evaluation results becomes high.

[0076] In the second embodiment, the evaluation value is calculated based on the period of the peak for each analysis frame in the axial position-pixel value, but the present invention is not limited to this. For example, the evaluation value may be calculated based on the frequency distribution for each pixel position of each pixel by performing a spatial frequency analysis for each line in the axial direction of the patchwork image.

[0077] Specifically, the calculation unit sets each line in the axial direction of the patchwork image as a line to be processed, and creates a graph of axial position-pixel value for the line to be processed, as shown in A of FIG. 25. The calculation unit performs time-frequency conversion by regarding the axial distance of the created graph of axial position-pixel value as a time axis, for example, converted to 1 ms per pixel. As a method of time-frequency conversion, short-time Fourier transform, wavelet transform, S-Transform, etc. can be applied. As a result, as shown in B of FIG. 25, an axial position-frequency distribution, which is a frequency distribution of pixel value changes at each position in the axial direction, is obtained. In the axial position-frequency distribution shown in B of FIG. 25, the intensity of the frequency is represented by a shade of color.

[0078] The evaluation unit evaluates the periodicity of pixel values ​​corresponding to rebar parts arranged at a predetermined interval based on the axial position-frequency distribution obtained by the calculation unit. For example, as shown in Fig. 26, the evaluation unit evaluates a portion where there is a distribution near a predetermined reference frequency (e.g., a frequency of 120 Hz) as a healthy portion, and evaluates a portion where there is no clear distribution as a deteriorated portion.

[0079] More specifically, if the intensity of each frequency in a predetermined frequency range including the reference frequency at each position in the axial position-frequency distribution is equal to or greater than a threshold, the evaluation unit evaluates the position as a healthy position, and if the intensity is less than the threshold, the evaluation unit evaluates the position as a deteriorated position. In the example of FIG. 26, the portion indicated by the solid line frame in the axial position-frequency portion has a frequency intensity less than the threshold. The evaluation unit may also evaluate a portion where the intensity of a frequency other than the predetermined frequency range is equal to or greater than a threshold, as indicated by the dashed line frame in the axial position-frequency distribution of FIG. 26, as a deteriorated portion. Furthermore, the evaluation unit may also evaluate a portion where the intensity of a frequency in a predetermined frequency range is equal to or greater than a threshold, but the intensity of a frequency other than the predetermined frequency range is equal to or greater than a threshold, as indicated by the dashed line frame in the axial position-frequency distribution of FIG. 26, as a deteriorated portion. The reference frequency and frequency range may be set to appropriate values ​​according to the interval between reinforcing bars.

[0080] The evaluation unit expresses the evaluation results based on the axial position-frequency distribution as a planar distribution. Fig. 27 shows an example of the evaluation results for a patchwork image including deteriorated areas (solid line frame in the upper diagram of Fig. 27). In the example of the evaluation results in Fig. 27, healthy areas are expressed in black, deteriorated areas in white, and areas showing a tendency to deteriorate in gray. In the example of Fig. 27, the deteriorated areas in the patchwork image roughly match the deteriorated areas indicated by the evaluation results.

[0081] In addition, the processing executed by the CPU after reading the software (program) in the above embodiment may be executed by various processors other than the CPU. In this case, examples of the processor include a PLD (Programmable Logic Device) such as an FPGA (Field-Programmable Gate Array) whose circuit configuration can be changed after manufacture, and a dedicated electric circuit such as an ASIC (Application Specific Integrated Circuit) which is a processor having a circuit configuration designed exclusively for executing a specific processing. The above processing may be executed by one of these various processors, or may be executed by a combination of two or more processors of the same or different types (for example, a plurality of FPGAs, a combination of a CPU and an FPGA, etc.). The hardware structure of these various processors is, more specifically, an electric circuit that combines circuit elements such as semiconductor elements.

[0082] In the above embodiment, the program is pre-stored (installed) in the storage device, but the present invention is not limited to this. The program may be provided in a form recorded in a storage medium such as a CD-ROM, a DVD-ROM (Digital Versatile Disc Read Only Memory), or a USB (Universal Serial Bus) memory. The program may be downloaded from an external device via a network.

[0083] The following additional information is disclosed below.

[0084] (Additional note 1) an acquisition unit that acquires a group of planar images for each of a plurality of depths of the reinforced concrete structure, the planar images representing, at each position on the surface of the reinforced concrete structure in which a plurality of reinforcing bars extending in a first direction are arranged at a predetermined interval along a second direction perpendicular to the first direction, the intensity of reflected waves of electromagnetic waves irradiated from the surface toward the interior of the reinforced concrete structure as pixel values ​​of pixels corresponding to the respective positions; a selection unit that selects the depth of the planar image to be used for evaluation for each region based on a statistical index calculated from pixel values ​​of pixels included in each of a plurality of regions obtained by dividing the planar image into a plurality of regions including one or more pixels; a calculation unit that calculates an evaluation value representing a change in pixel value in the second direction of a combined image obtained by combining the portions of the planar images corresponding to the depths selected by the selection unit for each of the regions; an evaluation unit that evaluates a deterioration and damage state of the reinforced concrete structure based on the evaluation value calculated by the calculation unit; A reinforced concrete structure evaluation device comprising:

[0085] (Additional note 2) A reinforced concrete structure evaluation device as described in Appendix 1, wherein the selection unit uses a wavelet transform coefficient calculated based on pixel values ​​of pixels included in the region as the statistical index.

[0086] (Additional note 3) The reinforced concrete structure evaluation device described in Appendix 2, wherein the selection unit uses, as the statistical index, a value obtained by logarithmically transforming the squared value of the wavelet transform coefficient calculated for each pixel of the planar image and performing Gaussian filter processing for each line in the second direction.

[0087] (Additional note 4) A reinforced concrete structure evaluation device as described in Appendix 2, wherein the selection unit uses, as the statistical index, a value obtained by taking an envelope of a waveform indicating the wavelet transform coefficient for one line in the second direction calculated for each pixel of the planar image.

[0088] (Additional note 5) A reinforced concrete structure evaluation device as described in any one of Supplementary Items 1 to 4, wherein the selection unit selects, for each region, the depth corresponding to the peak of the representative value in a graph showing the relationship between the representative value of the statistical index within the region and the depth.

[0089] (Additional note 6) 6. The reinforced concrete structure evaluation device according to claim 5, wherein the selection unit detects, as the peak, a maximum value of a graph obtained by performing Gaussian filter processing on the relationship between the representative value and the depth.

[0090] (Additional note 7) 7. A reinforced concrete structure evaluation device as described in claim 5 or 6, wherein the selection unit interpolates peaks in the areas where the peaks are not detected using peaks detected in surrounding areas.

[0091] (Additional note 8) 8. The reinforced concrete structure evaluation device according to any one of supplementary items 1 to 7, wherein the calculation unit calculates a wavelet transform coefficient for each pixel of the combined image as the evaluation value.

[0092] (Additional note 9) The reinforced concrete structure evaluation device described in Appendix 8, wherein the calculation unit calculates, as the evaluation value, a value obtained by logarithmically transforming the squared value of the wavelet transform coefficient calculated for each pixel of the combined image and performing Gaussian filter processing for each line in the second direction.

[0093] (Additional note 10) A reinforced concrete structure evaluation device as described in Appendix 9, wherein the calculation unit calculates, as the evaluation value, a value obtained by taking an envelope of a waveform indicating the wavelet transform coefficients for one line in the second direction calculated for each pixel of the combined image.

[0094] (Additional note 11) If the reinforced concrete structure has multiple layers in which reinforcing bars are present, The selection unit selects the depth corresponding to each of the layers in which the reinforcing bar exists, The calculation unit calculates the wavelet transform coefficient for each of the combined images corresponding to each of the layers by using a mother wavelet having a width corresponding to the layer. Item 11. The reinforced concrete structure evaluation device according to any one of items 8 to 10.

[0095] (Additional note 12) The reinforced concrete structure evaluation device according to claim 11, wherein the calculation unit widens the width of the mother wavelet for a deeper layer.

[0096] (Additional note 13) A reinforced concrete structure evaluation device as described in any one of Appendix 8 to Appendix 12, wherein the calculation unit selectively uses a mother wavelet of a width corresponding to the width in the second direction of the area representing the reinforcing bars in the combined image, and a mother wavelet of a width that reacts to the edges of the area representing the reinforcing bars in the combined image to calculate the wavelet transform coefficients.

[0097] (Additional note 14) The calculation unit calculates, as the evaluation value, a value obtained by performing a frequency analysis on the change in pixel value for each pixel position along a line in the second direction of the combined image.

[0098] (Additional note 15) The calculation unit calculates the evaluation value based on the peak frequency and the intensity at the peak frequency of a waveform indicating the change in pixel value for the pixel position within the analysis frame while sliding an analysis frame of a predetermined width by a predetermined distance along the second direction of the combined image.

[0099] (Additional note 16) The calculation unit performs spatial frequency analysis for each line in the second direction of the combined image, and calculates the evaluation value based on the frequency distribution for each pixel position of each pixel.

[0100] (Additional note 17) The reinforced concrete structure evaluation device according to any one of appendix 1 to appendix 16, wherein the evaluation unit evaluates the degree of deterioration and damage for each region of the combined image based on a comparison between the evaluation value of each pixel included in the region, which has the lowest evaluation value, and a predetermined threshold value.

[0101] (Additional note 18) The reinforced concrete structure evaluation device according to any one of Supplementary Items 1 to 17, wherein the evaluation unit displays an evaluation image in which each area of ​​the combined image is shown in a display mode corresponding to the evaluation result for each area.

[0102] (Additional note 19) The reinforced concrete structure evaluation device described in Appendix 18, wherein the evaluation unit displays an evaluation image in which each of the regions of the combined image is colored according to the lowest evaluation value among the evaluation values ​​of each pixel contained in the region.

[0103] (Additional note 20) an extraction unit that detects joints of the reinforced concrete structure from each of the planar images acquired by the acquisition unit and extracts an area between the detected joints as an evaluation target area; A reinforced concrete structure evaluation device according to any one of supplementary items 1 to 19, wherein each of the selection unit, the calculation unit, and the evaluation unit performs processing on the evaluation target area extracted by the extraction unit.

[0104] (Additional note 21) The reinforced concrete structure evaluation device according to any one of Supplementary Items 1 to 20, wherein the calculation unit calculates the evaluation value using the combined image expanded by adding pixels with interpolated pixel values ​​between pixels in the second direction of the combined image. [Explanation of symbols]

[0105] 10, 210 Reinforced concrete structure evaluation device 12 CPU 14. Memory 16 Storage device 18 Input Devices 20 Output Devices 22 Storage media reader 24 Communication I / F 26 Bus 32 Acquisition Department 34 Extraction part 36 Selection section 38, 238 Calculation section 40, 240 Evaluation Section 50 Electromagnetic wave equipment 60 Image processing device 90 vehicles 95 Reflected wave intensity detection range 100, 200 Reinforced concrete structure evaluation system

Claims

1. an acquisition unit that acquires a group of planar images for each of a plurality of depths of the reinforced concrete structure, the planar images representing, at each position on the surface of the reinforced concrete structure in which a plurality of reinforcing bars extending in a first direction are arranged at a predetermined interval along a second direction perpendicular to the first direction, the intensity of reflected waves of electromagnetic waves irradiated from the surface toward the interior of the reinforced concrete structure as pixel values ​​of pixels corresponding to the respective positions; a selection unit that selects the depth of the planar image to be used for evaluation for each region based on a statistical index calculated from pixel values ​​of pixels included in each of a plurality of regions obtained by dividing the planar image into a plurality of regions including one or more pixels; a calculation unit that calculates an evaluation value representing a change in pixel value in the second direction of a combined image obtained by combining the portions of the planar images corresponding to the depths selected by the selection unit for each of the regions; an evaluation unit that evaluates a deterioration and damage state of the reinforced concrete structure based on the evaluation value calculated by the calculation unit; A reinforced concrete structure evaluation device comprising:

2. The reinforced concrete structure evaluation device of claim 1, wherein the selection unit selects, for each region, the depth corresponding to the peak of the representative value in a graph showing the relationship between the representative value of the statistical indicator within the region and the depth.

3. The reinforced concrete structure evaluation device according to claim 2 , wherein the selection unit detects, as the peak, a maximum value of a graph obtained by performing Gaussian filter processing on the relationship between the representative value and the depth.

4. The reinforced concrete structure evaluation device according to claim 2 , wherein the selection unit interpolates a peak in the region where the peak is not detected, using peaks detected in surrounding regions.

5. The reinforced concrete structure evaluation device according to any one of claims 1 to 4, wherein the calculation unit calculates a wavelet transform coefficient for each pixel of the combined image as the evaluation value.

6. The reinforced concrete structure evaluation device described in claim 5, wherein the calculation unit calculates as the evaluation value a value obtained by logarithmically transforming the squared value of the wavelet transform coefficient calculated for each pixel of the combined image and performing Gaussian filter processing for each line in the second direction.

7. The reinforced concrete structure evaluation device described in claim 6, wherein the calculation unit calculates as the evaluation value a value obtained by taking an envelope of a waveform indicating the wavelet transform coefficients for one line in the second direction calculated for each pixel of the combined image.

8. If the reinforced concrete structure has multiple layers in which reinforcing bars are present, The selection unit selects the depth corresponding to each of the layers in which the reinforcing bar exists, The calculation unit calculates the wavelet transform coefficient for each of the combined images corresponding to each of the layers by using a mother wavelet having a width corresponding to the layer. The reinforced concrete structure evaluation device according to claim 5.

9. The reinforced concrete structure evaluation device of claim 5, wherein the calculation unit selectively uses a mother wavelet of a width corresponding to the width in the second direction of the area representing the reinforcing bar in the combined image, and a mother wavelet of a width that reacts to the edge of the area representing the reinforcing bar in the combined image to calculate the wavelet transform coefficients.

10. The calculation unit calculates, as the evaluation value, a value obtained by performing a frequency analysis on the change in pixel value for each pixel position along the line in the second direction of the combined image.A reinforced concrete structure evaluation device as described in any one of claims 1 to 4.

11. The reinforced concrete structure evaluation device of claim 10, wherein the calculation unit calculates the evaluation value based on the peak frequency of a waveform indicating the change in pixel value for the pixel position within the analysis frame and the intensity at the peak frequency while sliding an analysis frame of a predetermined width by a predetermined distance along the second direction of the combined image.

12. The reinforced concrete structure evaluation device described in claim 10, wherein the calculation unit performs spatial frequency analysis for each line in the second direction of the combined image and calculates the evaluation value based on the frequency distribution for each pixel position of each pixel.

13. The reinforced concrete structure evaluation device described in any one of claims 1 to 4, wherein the evaluation unit evaluates the degree of deterioration and damage for each region of the combined image based on a comparison between the evaluation value of each pixel contained in the region that has the lowest evaluation value and a predetermined threshold value.

14. A reinforced concrete structure evaluation device as described in any one of claims 1 to 4, wherein the evaluation unit displays an evaluation image in which each area of ​​the combined image is displayed in a display manner corresponding to the evaluation result for each area.

15. A reinforced concrete structure evaluation method executed by a reinforced concrete structure evaluation device including an acquisition unit, a selection unit, a calculation unit, and an evaluation unit, the acquisition unit acquires a group of planar images for each of a plurality of depths of the reinforced concrete structure, the planar images representing, at each position on a surface of the reinforced concrete structure in which a plurality of reinforcing bars extending in a first direction are arranged at a predetermined interval along a second direction perpendicular to the first direction, the intensity of a reflected wave of an electromagnetic wave irradiated from the surface toward the interior of the reinforced concrete structure as a pixel value of a pixel corresponding to the each position, the planar images being for each of a plurality of depths of the reinforced concrete structure; a selection unit selects the depth of the planar image to be used for evaluation for each region based on a statistical index calculated from pixel values ​​of pixels included in each of a plurality of regions obtained by dividing the planar image into a plurality of regions each including one or more pixels; a calculation unit calculates an evaluation value representing a change in pixel value in the second direction of a combined image obtained by combining portions of the planar images corresponding to the depths selected by the selection unit for each of the regions; An evaluation unit evaluates a deterioration and damage state of the reinforced concrete structure based on the evaluation value calculated by the calculation unit. Evaluation methods for reinforced concrete structures.

16. Computer, an acquisition unit that acquires a group of planar images for each of a plurality of depths of the reinforced concrete structure, the planar images representing, at each position on a surface of the reinforced concrete structure in which a plurality of reinforcing bars extending in a first direction are arranged at a predetermined interval along a second direction perpendicular to the first direction, the intensity of reflected waves of electromagnetic waves irradiated from the surface toward the interior of the reinforced concrete structure as pixel values ​​of pixels corresponding to the respective positions; a selection unit that selects the depth of the planar image to be used for evaluation for each region based on a statistical index calculated from pixel values ​​of pixels included in each of a plurality of regions obtained by dividing the planar image into a plurality of regions each including one or more pixels; a calculation unit that calculates an evaluation value representing a change in pixel value in the second direction of a combined image obtained by combining portions of the planar images corresponding to the depth selected by the selection unit for each of the regions; and an evaluation unit for evaluating a deterioration and damage state of the reinforced concrete structure based on the evaluation value calculated by the calculation unit; A reinforced concrete structure evaluation program to function as a.

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