JP7765945B2 - System for determining joint surface treatment and method for determining joint surface treatment - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act ・2021 National Convention 76th Annual Academic Lecture Summary (August 2, 2021) ・2021 National Convention 76th Annual Academic Lecture (September 9, 2021)

This invention relates to concrete joint surface treatment, and more specifically to a system and method for determining whether a concrete joint surface treatment is satisfactory based on images of the concrete surface.

Along with steel, concrete is one of the most important construction materials, and is used in a variety of structures, including civil engineering structures such as dams, tunnels, and bridges, as well as architectural structures such as apartment buildings and office buildings. These concrete structures are sometimes manufactured in advance in factories and transported to the desired location, but in the case of civil engineering and architectural structures, they are often constructed directly at the desired location (site). In either case, concrete structures are constructed by pouring concrete (fresh concrete), which is a mixture of cement, water, aggregate, admixtures, etc., into formwork, waiting for the concrete to harden, and then removing the formwork.

Fresh concrete is poured into the formwork by pouring it through a chute from an agitator truck, dropping it from a hose using a concrete pump truck, pouring it into the designated location through pre-installed pipes, or in some cases by workers splashing it with a shovel. The fresh concrete poured into the formwork is then vibrated using a vibrator (vibrating vibrator), and as liquefaction progresses due to this vibration, air bubbles within the concrete rise and escape to the outside, while the aggregate and mortar inside are rearranged, resulting in the concrete being compacted.

When constructing concrete structures of a certain height, such as dams or large retaining walls, it can sometimes be difficult to pour concrete all at once (i.e., for the entire height at the same time) due to construction conditions such as the concrete supply capacity and restrictions on the placement of concrete pumps. In such cases, it is common to plan the vertical block division (also known as lift division) in advance, taking into account conditions such as concrete supply capacity, and then pour the concrete. However, pouring concrete in upper and lower layer blocks with a time gap in between (overlapping) will result in pouring joints (especially horizontal joints) between the upper and lower layer blocks.

When fresh concrete is poured into a formwork, relatively heavy particles such as aggregate sink to the bottom, while relatively light particles such as cement tend to rise to the surface along with the bleeding water. Furthermore, if a certain amount of the light particles that rise to the surface accumulate on the concrete surface, a weak layer known as laitance, a layer of poor quality concrete, or loose aggregate may form. If the concrete of the upper layer of blocks is poured (joined) while such a laitance layer has formed on the surface of the concrete of the lower layer of blocks, a cold joint, which is a discontinuous surface, will be formed. This cold joint not only has a poor appearance, but it can also be a structural weakness, causing cracks and making it difficult to stop water.

Therefore, the "Standard Specifications for Concrete - Construction Edition" (hereinafter simply referred to as the "Standard Specifications") stipulates that "When joining concrete, laitance, poor-quality concrete, loose aggregate, etc. must be completely removed from the surface of the previously poured concrete, the concrete surface must be roughened, and the concrete must be allowed to absorb water thoroughly." The Standard Specifications also outline methods for treating the interface between the lower and upper layers of concrete (hereinafter referred to as the "joint surface"). For example, the Standard Specifications cite a treatment method called "green cut," which uses pressurized air or water to remove a thin layer of concrete surface (such as laitance) after the previously poured lower layer has finished setting, exposing the coarse aggregate. Furthermore, when performing green cut on large joint surfaces, some of the concrete begins to harden, making treatment difficult. Therefore, the Standard Specifications also recommend spraying a set retarder, primarily composed of sodium gluconate, on the concrete surface beforehand. In addition, various methods for treating joint surfaces depending on the strength of the concrete are shown, such as scraping the surface with a wire brush while spraying water on it, or sandblasting the surface and then rinsing it with water.

However, if the joint surface is carefully prepared over time, it will naturally be in good condition, but if it is done carelessly, the joint surface will not be properly roughened, which can lead to cold joints. Furthermore, if the joint surface is treated excessively, the joint surface will become extremely uneven, resulting in unnecessary wastage of labor and materials. For this reason, it is necessary to treat the joint surface while checking its condition. Traditionally, the quality of the joint surface was judged by skilled technicians with ample experience. However, the construction industry has recently been plagued by a chronic labor shortage, making it difficult to secure such skilled technicians. However, if an inexperienced technician judges the quality of the joint surface, they may make an incorrect judgment, resulting in inconveniences caused by insufficient or excessive treatment of the joint surface.

A variety of technologies have been proposed to quantitatively (objectively) determine the quality of concrete joint surface treatment, without relying on the subjective judgment of the judge, and without relying on the qualitative judgment of an engineer. For example, Patent Document 1 proposes a technology for evaluating the quality of concrete joint surface treatment by using photographed images of the concrete surface.

JP 2016-090360 A

The technology disclosed in Patent Document 1 divides image data of a construction joint surface into multiple image blocks, and evaluates the construction joint surface treatment by comparing the brightness histogram created for each image block with a predetermined threshold.In other words, it is an evaluation method that estimates the proportion of aggregate on the concrete surface based on the brightness histogram of the image block.This technology is advantageous because it allows for an objective evaluation of the construction joint surface treatment without relying on the subjective judgment of the engineer.

However, while the technology disclosed in Patent Document 1 is a method for estimating the presence of aggregate based on a brightness histogram, it does not directly estimate the distribution of aggregate. In other words, it is a method for evaluating the treatment of concrete joint surfaces without grasping (or estimating) the aggregate distributed on the concrete surface. As a result, those who obtain the assessment results cannot intuitively determine whether or not the results are correct, and even if they are skeptical of the assessment results based on actual conditions, there is no way to confirm them.

The objective of the present invention is to solve the problems inherent in conventional technology, namely, to provide a system and method for determining joint surface treatment that can estimate the distribution of aggregate on the concrete surface and objectively determine the quality of joint surface treatment.

The present invention was developed based on an unprecedented concept: by smoothing an original image, two types of smoothed images are generated: one that emphasizes aggregates and one that makes aggregates less noticeable; and the distribution of aggregates on the concrete surface is estimated based on the difference between these two types of smoothed images.

The construction joint surface treatment assessment system of the present invention is a system that assesses the quality of construction joint surface treatment based on an original image of a concrete surface, and is equipped with a smoothing processing means and an aggregate extraction means. The smoothing processing means generates a first smoothed image and a second smoothed image by smoothing the original image, while the aggregate extraction means calculates the pixel value difference between the first smoothed image and the second smoothed image and extracts, as aggregate portions, portions where the pixel value difference exceeds an aggregate threshold. The first smoothed image is an image generated by smoothing processing so that the aggregate is emphasized more than in the second smoothed image. The quality of construction joint surface treatment can then be assessed based on the proportion of aggregate portions in the target area corresponding to the original image.

The construction joint surface treatment determination system of the present invention can also be equipped with a treatment level determination means. This treatment level determination means calculates the aggregate distribution ratio of the target area that is occupied by aggregate, and determines the level of construction joint surface treatment in the target area by comparing the aggregate distribution ratio with a treatment level threshold.

The joint surface treatment determination system of the present invention can also be configured so that the degree of joint treatment, which indicates the degree of treatment for the joint surface, is set in three or more stages. In this case, two or more treatment level thresholds are set in stages in advance, and the treatment level determination means determines the degree of joint treatment in the target area by comparing the aggregate distribution ratio with two or more treatment level thresholds.

The construction joint surface treatment determination system of the present invention can also determine the degree of construction joint surface treatment in a divided target area (multiple areas into which the target area is divided). In this case, the treatment level determination means calculates the aggregate distribution ratio for each divided target area and determines the degree of construction joint surface treatment.

The construction joint surface treatment determination system of the present invention can also generate a first smoothed image and a second smoothed image by performing median filter processing on the original image. Note that a filter size larger than the filter size used to generate the first smoothed image is used to generate the second smoothed image.

The construction joint surface treatment determination system of the present invention can also generate a first smoothed image and a second smoothed image by performing median filter processing using a predetermined filter size. For example, the filter size used to generate the first smoothed image is set to encompass the smallest aggregate to be extracted, and the filter size used to generate the second smoothed image is set to a range larger than the largest aggregate to be extracted.

The method for determining the quality of construction joint surface treatment of the present invention is a method for determining the quality of construction joint surface treatment based on original images of the concrete surface, and includes an index image acquisition process, an aggregate threshold setting process, an original image acquisition process, and an aggregate extraction process. In the index image acquisition process, an index image is acquired by photographing the surface of test concrete (concrete formed in test construction) that has been subjected to construction joint surface treatment, and the index image is smoothed to generate a first smoothed index image and a second smoothed index image. In the aggregate threshold setting process, the pixel value difference between the first smoothed index image and the second smoothed index image is calculated, and the aggregate threshold (the threshold for extracting aggregate portions) is set by comparing these pixel value differences with the index image. In the original image acquisition process, an original image is acquired by photographing the surface of permanent concrete (concrete formed in actual construction) that has been subjected to construction joint surface treatment, and the original image is smoothed to generate a first smoothed image and a second smoothed image. In the aggregate extraction process, the pixel value difference between the first smoothed image and the second smoothed image is calculated, and areas where this pixel value difference exceeds the aggregate threshold are extracted as aggregate areas. The first smoothed index image is an image generated by smoothing processing so that the aggregate is emphasized more than in the second smoothed index image. The quality of the construction joint surface treatment can then be determined based on the proportion of aggregate areas in the target area corresponding to the original image.

The joint surface treatment determination system and joint surface treatment determination method of the present invention have the following effects.
(1) It is possible to objectively evaluate the construction joint surface treatment without relying on the subjective judgment of the evaluator. As a result, it is possible to construct concrete structures that have excellent mechanical properties, durability, waterproofing, and appearance.
(2) Objective evaluation becomes possible, which avoids the difficulty of securing skilled engineers with ample experience.
(3) In addition to objective evaluation, the reproducibility of the evaluation, i.e., traceability of the evaluation, can be ensured, which improves the reliability of the evaluation of joint surface treatment and also enables accountability, thereby gaining the trust of customers.
(4) Based on the results of experimental implementation of the present invention, good judgment results were obtained regardless of whether the concrete surface was dry or wet. Furthermore, good judgment results were obtained even when using original images taken at an oblique angle (for example, at a 45° angle) rather than facing directly at the image.

FIG. 1 is a block diagram showing the main configuration of the joint surface treatment determination system of the present invention. FIG. 1 is a model diagram showing a "filter" in median filtering. FIG. 10 is a model diagram schematically showing a “difference image” based on pixel value differences between a “first smoothed image” and a “second smoothed image.” FIG. 10 is a model diagram showing a "segmentation target region" formed by dividing a differential image. FIG. 1 is a flow chart showing the main processing flow of the joint surface treatment determination system of the present invention. A flow chart showing the main processing flow of the joint surface treatment determination system of the present invention, up to determining the aggregate threshold value and the treatment level threshold value. 1 is a flow chart showing the main steps of the joint surface treatment determination method of the present invention. (a) is a model diagram showing the results of determining the degree of joint surface treatment of a dry concrete surface using the joint surface treatment determination system, and (b) is a model diagram showing the results of determining the degree of joint surface treatment of a wet concrete surface using the joint surface treatment determination system.

Examples of the construction joint surface treatment determination system and construction joint surface treatment determination method of the present invention are explained below with reference to the accompanying drawings.

1. Construction joint surface treatment determination system First, the construction joint surface treatment determination system of the present invention will be described in detail. The construction joint surface treatment determination method of the present invention is a method for determining the quality of construction joint surface treatment using the construction joint surface treatment determination system of the present invention. Therefore, the construction joint surface treatment determination system of the present invention will be described first, and then the construction joint surface treatment determination method of the present invention will be described.

Figure 1 is a block diagram showing the main components of the construction joint surface treatment determination system 100 of the present invention. As shown in this figure, the construction joint surface treatment determination system 100 of the present invention is configured to include a smoothing processing means 101 and an aggregate extraction means 102, and can also be configured to include a processing level determination means 103, an output means 104, an original image storage means 105, etc.

Of the main components of the construction joint surface treatment assessment system 100, the smoothing means 101, aggregate extraction means 102, and treatment level assessment means 103 can be manufactured as dedicated units or can be made using general-purpose computer equipment. This computer equipment includes a processor such as a CPU, memory such as ROM and RAM, input means such as a mouse and keyboard, and a display. It can be configured as a personal computer (PC), a tablet PC such as an iPad (registered trademark), or a mobile device such as a smartphone. The output means 104 outputs images, etc., such as a display or printer, and can be, for example, a personal computer display.

One feature of the present invention is the use of an image (hereinafter referred to as the "original image") of a concrete surface (i.e., a concrete joint surface) after a concrete joint treatment such as green cutting has been performed on the surface. The original image can be taken by a person (e.g., a worker), by a digital camera or digital video mounted on a mobile cart, or by a digital camera mounted on a UAV (Unmanned Aerial Vehicle). The original image storage means 105 stores the original image and can be a general-purpose computer storage device or can be built on a database server. If built on a database server, it can be placed on a local network (LAN: Local Area Network), or it can be a cloud server that stores the image via the Internet.

Below, we will provide a detailed explanation of each of the main elements that make up the construction joint surface treatment determination system 100.

(Smoothing processing means)
The smoothing processing means 101 is a means for generating a "first smoothed image" and a "second smoothed image" by smoothing the original image read from the original image storage means 105 (FIG. 1). Here, smoothing processing is a process performed for the purpose of clarifying a target object in the image or removing noise in the image, and examples of methods include median filtering, averaging filtering, weighted average filtering, and Gaussian filtering. The construction joint surface treatment determination system 100 of the present invention can also employ these smoothing processes and various other conventional methods.

Median filtering, a type of smoothing process, involves setting up a filter (also called a kernel) as shown in Figure 2 and converting the "pixel value" of each pixel while moving the filter. Here, pixel values refer to values such as grayscales representing shades of gray, color information such as RGB or CMYK, or a combination of grayscale and color information—i.e., physical property values that form the basis of rendering. This median filtering process is characterized by extracting the median pixel value (hereinafter referred to as the "median pixel value") of the pixels contained within the filter, and assigning this median pixel value to a specific pixel within the filter (e.g., the pixel at the center of the filter). For example, in the case of Figure 2, the filter contains nine pixels (Nos. 23-25, 33-35, and 43-45). The median pixel value is calculated from these nine pixel values, and the original pixel of the pixel at the center of the filter (No. 34) is converted to this median pixel value. Median filtering calculates the converted pixel value from the pixel value within the filter, so naturally the image after smoothing will differ depending on the size of the filter (hereafter referred to as "filter size").

The first smoothed image is an image obtained by performing a smoothing process to emphasize the aggregates contained in the original image. On the other hand, the second smoothed image is an image obtained by performing a smoothing process to de-emphasize the aggregates contained in the original image, in other words, to make the entire image closer to the background color of the original image. Therefore, the first smoothed image can be said to be an image generated by a smoothing process to emphasize the aggregates more than the second smoothed image. For example, when median filter processing is used as the smoothing process, the first smoothed image and the second smoothed image can be generated by changing the filter size. More specifically, if the filter used to generate the first smoothed image is referred to as the "first filter" and the filter used to generate the second smoothed image is referred to as the "second filter," the smoothing processing means 101 generates the first smoothed image using the first filter, which has a filter size smaller than the second filter, and generates the second smoothed image using the second filter, which has a filter size larger than the first filter.

As described below, the smoothing processing means 101 performs smoothing processing to extract aggregate (particularly coarse aggregate) from the original image. Concrete contains coarse aggregate of various diameters. However, when determining the quality of the joint surface treatment, it is not necessary to extract extremely small (or large) diameter coarse aggregate; extracting coarse aggregate within a specified diameter range (e.g., 5 to 20 mm) may be sufficient. Therefore, it is possible to set the filter sizes of the first and second filters according to the minimum (e.g., 5 mm) and maximum (e.g., 20 mm) diameters of the coarse aggregate to be extracted. The inventors discovered that coarse aggregate can be extracted more clearly by setting the filter size of the first filter to encompass the smallest diameter coarse aggregate to be extracted, and setting the filter size of the second filter to encompass a larger range than the largest diameter coarse aggregate to be extracted. Specifically, the filter size (i.e., the number of pixels it comprises) is set by dividing the projected area of the smallest diameter coarse aggregate by the resolution (the area of one pixel), and the filter size is set by dividing the projected area of the largest diameter coarse aggregate by the resolution and multiplying it by a predetermined magnification (for example, 1.5 times).

The smoothing processing means 101 can perform smoothing processing on each original image to generate a first smoothed image and a second smoothed image, or it can perform smoothing processing on a composite image made by stitching together multiple original images to generate a first smoothed image and a second smoothed image, or it can perform smoothing processing on an orthogonally transformed image (orthoimage) made up of multiple original images to generate a first smoothed image and a second smoothed image.

(Aggregate Extraction Means)
The aggregate extraction means 102 calculates the difference in pixel values between the first smoothed image and the second smoothed image (hereinafter simply referred to as the "pixel value difference") and extracts the portion where this pixel value difference exceeds a predetermined threshold (hereinafter simply referred to as the "aggregate threshold") as the "portion where aggregate (particularly coarse aggregate) is captured (hereinafter simply referred to as the "aggregate portion")" (FIG. 1). When calculating the pixel value difference, it is of course necessary to compare pixels in the first smoothed image with corresponding pixels in the second smoothed image, in other words, pixels located at the same position in each image, and then calculate the difference in pixel values. Note that the pixel value difference can be calculated as a positive or negative value, or as an absolute value. Furthermore, by calculating the pixel value differences of all pixels constituting an image, it is possible to generate an image based on the pixel value differences (hereinafter simply referred to as the "difference image") as shown in FIG. 3.

When the aggregate extraction means 102 generates a difference image, it compares the pixel value difference with the aggregate threshold for each pixel and extracts pixels with pixel value differences that exceed this aggregate threshold as "aggregate parts." At this time, it may be configured to extract aggregate parts on a pixel-by-pixel basis, or to extract parts where a cluster of a predetermined number of pixels or more is formed as an aggregate part, or to correct and extract pixels that are not determined to be aggregate parts surrounded by pixels determined to be aggregate parts. Furthermore, the aggregate extraction means 102 does not necessarily need to generate a difference image (although it may of course generate one), and may instead extract aggregate parts based solely on the calculated pixel value difference.

To properly extract aggregate, a reference aggregate threshold is essential. This aggregate threshold can be set empirically or after conducting test construction. It can also be set separately for cases where the concrete surface is dry and cases where it is wet. It can also be set differently depending on the shooting conditions (e.g., sunny or cloudy) or the concrete mix (particularly the type of cement and coarse aggregate used). Below, we will explain in detail an example of setting the aggregate threshold after conducting test construction. First, a test concrete (hereinafter simply referred to as "test concrete") is constructed, and the test concrete surface is treated with a joint surface treatment before an image (hereinafter referred to as "index image") is obtained. Next, a first smoothed image and a second smoothed image are generated based on the index image. Difference images are generated while varying the aggregate threshold, and the most appropriate aggregate threshold is determined by comparing each difference image with the index image.

In this way, the aggregate portion is extracted by calculating the pixel value difference between the first smoothed image in which the aggregate is emphasized and the second smoothed image in which the background color of the original image is used, so to speak. This makes it possible to extract the aggregate portion more clearly than, for example, judging from the first smoothed image alone. The aggregate extraction means 102 can extract the aggregate portion based on the first and second smoothed images generated for each original image, or based on the first and second smoothed images generated for a composite image created by stitching together multiple original images, or based on the first and second smoothed images generated for an orthogonally transformed image (orthoimage) made up of multiple original images.

(Processing level determination means)
When the aggregate portion is extracted by the aggregate extraction means 102, the proportion of the aggregate portion in the range of the concrete surface corresponding to the original image (hereinafter referred to as the "target area") can be ascertained, and a person (for example, a worker) can thereby determine the quality of the joint surface treatment. Alternatively, the proportion of the target area that is occupied by aggregate portions (hereinafter referred to as the "aggregate distribution proportion") can be calculated, and then the quality of the joint surface treatment can be quantitatively determined.

The processing level determination means 103 calculates the aggregate distribution ratio based on the area (or total number of pixels) of the difference image (or the original image) and the area (or number of pixels) of the aggregate portion, and determines the degree of construction joint surface processing in the target area (hereinafter simply referred to as the "construction joint surface processing level") by comparing the aggregate distribution ratio with a predetermined threshold (hereinafter referred to as the "processing level threshold") (Figure 1). Specifically, the aggregate distribution ratio is calculated by dividing the area of the aggregate portion by the area of the difference image, and the construction joint surface processing level is determined by comparing the aggregate distribution ratio with the processing level threshold. For example, if the processing level threshold is set as the boundary between "insufficient construction joint surface processing" and "good construction joint surface processing," the construction joint surface processing level is determined to be "insufficient" when the aggregate distribution ratio is below the processing level threshold, and conversely, the construction joint surface processing level is determined to be "good" when the aggregate distribution ratio is above the processing level threshold. Alternatively, if a processing level threshold is set as the boundary between "good construction joint surface" and "over-processed construction joint surface," the processing level of the construction joint surface is determined to be "good" when the aggregate distribution ratio is below the processing level threshold, and conversely, if the aggregate distribution ratio is above the processing level threshold, the processing level of the construction joint surface is determined to be "over-processed." Of course, by setting two or more processing level thresholds in advance, such as setting a first processing level threshold as the boundary between "insufficiently processed construction joint surface" and "good construction joint surface," and setting a second processing level threshold as the boundary between "good construction joint surface" and "over-processed construction joint surface," it is possible to determine the processing level of the construction joint surface in three or more stages (for example, "insufficient," "good," "over-processed," etc.).

The processing level determination means 103 can calculate the aggregate distribution ratio in units of the original image (for example, using the difference image as one unit) to determine the degree of processing of the pour joint surface, or it can calculate the aggregate distribution ratio for each region (hereinafter referred to as the "division target region") into which the original image (or difference image) is divided, as shown in Figure 4, to determine the degree of processing of the pour joint surface. Specifically, the aggregate distribution ratio for a division target region is calculated by dividing the area of the aggregate portion included in the division target region by the area of that division target region. For example, in Figure 4, six division target regions are formed by dividing the difference image, and in this case the processing level determination means 103 calculates the aggregate distribution ratio for each of the six division target regions and determines the degree of processing of the pour joint surface for each.

To properly determine the degree of concrete joint treatment, a standard treatment threshold is essential. Like the aggregate threshold, this treatment threshold can be set empirically or after conducting test construction. It can also be set separately for cases where the concrete surface is dry and cases where it is wet. Different aggregate thresholds can also be set depending on the imaging conditions and concrete mix. Below, we explain in detail an example of setting the aggregate threshold after test construction. First, test concrete is constructed and the test concrete surface is treated with a treatment. At this time, the treatment is performed to achieve different degrees of treatment, such as "insufficient treatment," "good treatment," or "over-treatment," i.e., multiple test pieces are prepared. Then, index images are acquired for each test piece. A difference image is generated based on each index image, and the aggregate distribution ratio is calculated. An appropriate treatment threshold is then set based on the degree of treatment of the concrete joint in the difference image. For example, by checking the index image, it is possible to identify areas where the "placement joint surface is good," extract the aggregate distribution ratio for the corresponding target area for division, and then set the upper and lower limits of the aggregate distribution ratio for which the "placement joint surface is good" as the treatment level threshold. Furthermore, by constructing multiple (n pieces here) test concretes and performing multiple stages (m stages here) of placement joint surface treatment level processing, multiple (n x m) test pieces are prepared (i.e., n x m index images are obtained), and then setting the treatment level threshold, it is possible to set a treatment level threshold that is more suited to the current situation, which is preferable.

(Processing flow)
The main processing flow when using the construction joint surface treatment determination system 100 of the present invention will be described with reference to Figure 5. Figure 5 is a flow diagram showing the main processing flow of the construction joint surface treatment determination system 100, with the central column showing the processing to be performed, the left column showing the input information required for that processing, and the right column showing the output information resulting from that processing.

Once a concrete surface that has hardened to a certain extent has undergone joint surface treatment, the concrete surface is photographed, for example, using a digital camera mounted on a UAV, to obtain an original image (Step 101 in Figure 5). Once the original image is stored in the original image storage means 105 (Figure 1), the smoothing processing means 101 reads the original image and performs a smoothing process, such as median filtering, on the original image to generate a first smoothed image and a second smoothed image (Step 102 in Figure 5).

Once the first smoothed image and the second smoothed image have been generated, the aggregate extraction means 102 calculates the pixel value difference to generate a difference image (Step 103 in Figure 5), and compares the pixel value difference with an aggregate threshold to generate an image in which the aggregate portion has been extracted (hereinafter referred to as the "aggregate distribution image") (Step 104 in Figure 5). Once the aggregate distribution image has been generated, the processing level determination means 103 sets regions to be divided (Step 105 in Figure 5), calculates the aggregate distribution ratio for each region to be divided based on the area of the difference image (the difference image of the region to be divided) and the area of the aggregate portion (the aggregate portion included in the region to be divided) (Step 106 in Figure 5), and further determines the degree of processing of the pour joint surface for each region to be divided by comparing the aggregate distribution ratio with the processing level threshold (Step 107 in Figure 5).

As mentioned above, the aggregate threshold and treatment level threshold can be set by conducting test construction, and in this case the construction joint surface treatment determination system 100 can be used. Figure 6 is a flow diagram showing the main processing flow up to determining the aggregate threshold and treatment level threshold among the processing steps of the construction joint surface treatment determination system 100, with the central column showing the processing to be performed, the left column showing the input information required for that processing, and the right column showing the output information resulting from that processing. Below, with reference to Figure 6, the processing flow up to setting the aggregate threshold and treatment level threshold using the construction joint surface treatment determination system 100 will be explained.

First, test concrete is constructed, and the surface of the test concrete is subjected to joint surface treatment. At this time, joint surface treatment is performed to achieve different degrees of joint surface treatment, such as "insufficient joint surface treatment," "good joint surface treatment," or "over-treated joint surface treatment." In other words, multiple types of test pieces are prepared. Once multiple types of test pieces are prepared, an index image is acquired for each test piece (Step 111 in Figure 6). Once the index image is stored in the raw image storage means 105, the smoothing processing means 101 reads the index image and performs a smoothing process, such as median filter processing, on the index image to generate a first smoothed image (hereinafter referred to as the "first smoothed index image") and a second smoothed image (hereinafter referred to as the "second smoothed index image") (Step 102 in Figure 6).

Once the first smoothed index image and the second smoothed index image are generated, the aggregate extraction means 102 calculates the pixel value difference and generates a difference image (hereinafter referred to as the "difference index image") (Step 103 in Figure 6). Next, a provisionally determined aggregate threshold (hereinafter simply referred to as the "provisional aggregate threshold") is input by the operator (Step 112 in FIG. 6), and the aggregate extraction means 102 compares the difference index image with the provisional aggregate threshold to generate an image in which the aggregate portion has been provisionally extracted (hereinafter referred to as the "provisional aggregate distribution image") (Step 104 in FIG. 6). The provisional aggregate distribution image and the index image are then compared, and if it is determined that the aggregate distributions generally match (Yes in Step 113 in FIG. 6), the process proceeds to the subsequent process; if it is determined that the aggregate distributions do not match (No in Step 113 in FIG. 6), a different provisional aggregate threshold is set (Step 112 in FIG. 6) and the predetermined process (Steps 104 to 113 in FIG. 6) is repeatedly executed.

Once the aggregate threshold is officially determined (Step 114 in Figure 6), the aggregate extraction means 102 again calculates pixel value differences and generates difference images based on the index images acquired for each degree of concrete joint surface treatment, as well as an aggregate distribution image (Step 104 in Figure 6). Once an aggregate distribution image has been generated for each index image, the treatment level determination means 103 sets each division target region and calculates the aggregate distribution ratio for each division target region based on the area of the difference image and the area of the aggregate portion (Step 106 in Figure 6). An appropriate treatment level threshold is then set according to the degree of concrete joint surface treatment associated with the difference image (Step 115 in Figure 6).

2. Construction joint surface treatment determination method Next, the construction joint surface treatment determination method of the present invention will be explained with reference to Figure 7. Note that the construction joint surface treatment determination method of the present invention is a method for determining whether the construction joint surface treatment is good or bad using the construction joint surface treatment determination system 100 described up to this point, and therefore we will avoid overlapping explanations with the contents explained in the construction joint surface treatment determination system 100 and will only explain the contents unique to the construction joint surface treatment determination method of the present invention. In other words, the contents not described here are the same as those explained in "2. Construction joint surface treatment determination system".

As shown in Figure 7, the construction joint surface treatment assessment method of the present invention can be broadly divided into "trial construction" and "actual construction," enclosed by dashed lines. As explained above, trial construction is a process carried out to set the aggregate threshold and treatment level threshold. Therefore, if the aggregate threshold and treatment level threshold have already been obtained, the construction joint surface treatment assessment method can be carried out without trial construction. However, for convenience, an example including trial construction will be explained here.

(Test construction)
First, a test concrete is constructed, and the surface of the test concrete is subjected to a joint surface treatment (Step 211 in FIG. 7 ). At this time, the joint surface treatment is performed to achieve different degrees of joint surface treatment, such as "insufficient joint surface treatment,""good joint surface treatment," or "over-treated joint surface treatment." In other words, multiple types of test pieces are prepared. Once multiple types of test pieces are prepared, an index image is acquired for each test piece (Step 212 in FIG. 7 ). Once the index image is acquired, a smoothing process (e.g., median filter processing) is performed on the index image using the smoothing processing means 101 to generate a first smoothed index image and a second smoothed index image (Step 213 in FIG. 7 ). After the first smoothed index image and the second smoothed index image are generated, the aggregate extraction means 102 is used to generate a difference index image (Step 214 in FIG. 7 ). The aggregate extraction means 102 is further used to generate provisional aggregate distribution images while varying the provisional aggregate threshold value, and the provisional aggregate distribution image is compared with the index image to determine the aggregate threshold value (Step 215 in FIG. 7 ). Once the aggregate threshold value has been officially determined, the aggregate extraction means 102 is used to generate a difference image based on the index image for each degree of concrete joint surface treatment, and an aggregate distribution image is also generated. The treatment level determination means 103 is then used to calculate the aggregate distribution ratio for each region to be divided, and an appropriate treatment level threshold value is set (Step 215 in FIG. 7 ).

(Implementation work)
First, actual permanent concrete (hereinafter referred to as "permanent concrete") is constructed, and joint surface treatment is performed on the surface of the permanent concrete (Step 221 in FIG. 7 ). Then, an original image is obtained by photographing the surface of the permanent concrete that has undergone joint surface treatment (Step 222 in FIG. 7 ). Once the original image is obtained, smoothing processing (e.g., median filter processing) is performed on the original image using the smoothing processing means 101 to generate a first smoothed image and a second smoothed image (Step 223 in FIG. 7 ). Once the first smoothed image and the second smoothed image have been generated, a difference image is generated using the aggregate extraction means 102 (Step 224 in FIG. 7 ), and an aggregate distribution image in which aggregate portions have been extracted is generated using the aggregate extraction means 102 (Step 225 in FIG. 7 ). Once the aggregate distribution image is generated, the processing degree determination means 103 is used to calculate the aggregate distribution ratio for each division target area (Step 226 in Figure 7), and to determine the joint surface processing degree for each division target area (Step 227 in Figure 7).

3. Experimental Results The inventors of the present invention conducted an experiment to determine the quality of the joint surface treatment using the present invention. Figure 8 is a model diagram showing the results of determining the degree of joint surface treatment of a concrete surface using the joint surface treatment determination system 100, where (a) is the result of an experiment conducted specifically for a dry concrete surface, and (b) is the result of an experiment conducted specifically for a wet concrete surface. In this experiment, test pieces with "insufficient" joint surface treatment, "good" test pieces, and "over-treated" test pieces were used.

As can be seen from Figure 8, when the original image of a test piece determined to be "insufficient" is processed by the construction joint surface treatment determination system 100, a relatively large number of segmentation target areas with an "insufficient" degree of construction joint treatment are output; when the original image of a test piece determined to be "good" is processed by the construction joint surface treatment determination system 100, a relatively large number of segmentation target areas with a "good" degree of construction joint treatment are output; and when the original image of a test piece determined to be "overtreated" is processed by the construction joint surface treatment determination system 100, a relatively large number of segmentation target areas with an "overtreated" degree of construction joint treatment are output. Furthermore, the results processed by the construction joint surface treatment determination system 100 generally match the actual condition, regardless of the condition of the concrete surface (whether dry or wet). In this way, the present invention can extremely effectively determine the quality of construction joint surface treatment.

The construction joint surface treatment determination system and construction joint surface treatment determination method of the present invention can be used in a variety of concrete structures, including civil engineering structures such as dams, tunnels, and bridges, and architectural structures such as apartment buildings and office buildings. By achieving appropriate construction joint surface treatment, the present invention can build concrete structures with excellent mechanical performance, durability, watertightness, and appearance, thereby providing high-quality infrastructure. Considering this, the invention can be said to be not only applicable industrially, but also to be expected to make a significant contribution to society.

100 Construction joint surface treatment determination system of the present invention 101 Smoothing processing means (of construction joint surface treatment determination system) 102 Aggregate extraction means (of construction joint surface treatment determination system) 103 Processing degree determination means (of construction joint surface treatment determination system) 104 Output means (of construction joint surface treatment determination system) 105 Original image storage means (of construction joint surface treatment determination system)

Claims (7)

A system for determining whether or not joint surface treatment is good based on an original image of a concrete surface,
a smoothing processing means for smoothing the original image to generate a first smoothed image and a second smoothed image;
an aggregate extraction means for calculating a pixel value difference between the first smoothed image and the second smoothed image and extracting a portion where the pixel value difference exceeds an aggregate threshold as an aggregate portion;
the first smoothed image is an image generated by smoothing processing so that aggregates are more emphasized than in the second smoothed image,
The quality of the joint surface treatment can be determined based on the proportion of the aggregate portion occupying the target area corresponding to the original image.
A joint surface treatment determination system characterized by: The method further includes a processing level determination means for calculating the aggregate distribution ratio of the aggregate portion in the target area and determining the degree of processing of the joint surface in the target area by comparing the aggregate distribution ratio with a processing level threshold.
2. The joint surface treatment determination system according to claim 1. By setting two or more processing degree thresholds in stages in advance, the joint processing degree representing the degree of processing of the joint surface processing is set in three or more stages,
The processing degree determination means determines the degree of joint processing in the target area by comparing the aggregate distribution ratio with two or more of the processing degree thresholds.
3. The joint surface treatment determination system according to claim 2. The processing degree determination means calculates the aggregate distribution ratio for each of a plurality of divided target areas obtained by dividing the target area, and determines the degree of construction joint surface processing in the divided target area.
4. The joint surface treatment determination system according to claim 2 or 3. the smoothing processing means generates the first smoothed image by performing median filtering on the original image;
and the smoothing processing means generates the second smoothed image by performing median filtering on the original image using a filter size larger than the filter size used to generate the first smoothed image.
The joint surface treatment determination system according to any one of claims 1 to 4. a filter size used to generate the first smoothed image is set so as to encompass the smallest aggregate to be extracted;
The filter size used to generate the second smoothed image is set to a range larger than the largest aggregate to be extracted.
6. The joint surface treatment determination system according to claim 5. A method for determining whether or not a concrete joint surface treatment is good based on an original image of the concrete surface,
an index image acquisition step of performing joint surface treatment on the surface of the test concrete formed in the test construction, acquiring an index image by photographing the surface of the test concrete, and smoothing the index image to generate a first smoothed index image and a second smoothed index image;
an aggregate threshold setting step of calculating a pixel value difference between the first smoothed index image and the second smoothed index image, and comparing the pixel value difference with the index image to set an aggregate threshold for extracting an aggregate portion;
an original image acquisition process in which a surface of the permanent concrete formed in the construction work is subjected to a joint surface treatment, the surface of the permanent concrete is photographed to acquire the original image, and a first smoothed image and a second smoothed image are generated by smoothing the original image;
an aggregate extraction step of calculating a pixel value difference between the first smoothed image and the second smoothed image, and extracting a portion where the pixel value difference exceeds the aggregate threshold as an aggregate portion,
the first smoothed index image is an image generated by smoothing processing so that aggregates are emphasized more than in the second smoothed index image, and the first smoothed image is an image generated by smoothing processing so that aggregates are emphasized more than in the second smoothed image,
determining whether the joint surface treatment is good or bad based on the proportion of the aggregate portion occupying the target area corresponding to the original image;
A method for determining joint surface treatment.