JP2016042069A - Concrete surface layer quality evaluation device and concrete surface layer quality evaluation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine a surface layer quality of a concrete structure relative to each classification.SOLUTION: Color image data obtained by photographing the surface of a concrete structure are acquired, and a content stored in storage means for storing the range of a color corresponding to a surface layer quality relative to each classification of a surface layer quality of the concrete structure is compared with a color of each pixel included in the acquired color image data, to thereby determine the surface layer quality of the concrete structure relative to each classification.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a technique for evaluating the surface quality of concrete.

  As a technique for evaluating the surface quality of concrete, for example, techniques disclosed in Patent Documents 1 and 2 are known. In Patent Document 1, images of concrete test specimens before and after the occurrence of white bloom are taken, the average values of all RGB contained in the respective image data are calculated, and the sum of the values is RGB. By calculating the total value and subtracting the RGB total value before the white bloom from the RGB total value after the white bloom occurs, the RGB variation value is calculated. Techniques for evaluation are disclosed. Patent Document 2 discloses a technique for binarizing image data on a concrete surface and extracting an image area corresponding to a weak part.

JP 2014-41027 A Japanese Patent Laid-Open No. 2001-20660

However, the technique disclosed in Patent Document 1 cannot individually determine the surface layer quality such as surface bubbles and cracks. In the technique using binarization disclosed in Patent Document 2, since the threshold value is narrow, a recognition error is likely to occur, and the degree to which light such as illumination hits is also easily affected.
Then, this invention provides the technique which can determine the surface layer quality of a concrete structure for every classification.

  The present invention provides acquisition means for acquiring color image data obtained by photographing the surface of a concrete structure, storage means for storing a color range corresponding to the surface layer quality for each type of surface layer quality of the concrete structure, and acquisition Determining means for comparing the color of each pixel included in the color image data with the color range stored in the storage means and determining the surface layer quality of the concrete structure for each type; A concrete surface quality evaluation apparatus is provided.

In the above-described configuration, the determination unit determines the surface quality of a plurality of types indicated by pixels included in a common color range in the acquired color image data by distinguishing them from each other according to the shape or size corresponding to the type. May be.
In the above configuration, the color range corresponding to the surface layer quality stored by the storage unit is a color range determined based on an image obtained by photographing the surface of the concrete structure as a surface layer determination target in advance. It may be.
In the above configuration, the color range corresponding to the surface layer quality stored by the storage unit is determined based on a difference from the most frequently occurring color in an image obtained by photographing the surface of the concrete structure that is the target of surface layer quality determination. It may be a range of colors.

  The present invention also provides an acquisition step for acquiring color image data obtained by photographing the surface of a concrete structure, and a storage means for storing a color range corresponding to the surface layer quality for each type of surface layer quality of the concrete structure. A concrete surface quality evaluation method comprising: a determination step of comparing the content of the generated content and the color of each pixel included in the acquired color image data and determining the surface layer quality of the concrete structure for each type provide.

  According to the present invention, the surface quality of a concrete structure can be determined for each type.

The figure which shows the whole structure of embodiment. The figure which shows the hardware constitutions of the concrete surface quality evaluation apparatus 100. The figure which shows the criteria of surface layer quality. The figure which shows the content of pixel DB300. The flowchart which shows the procedure of the process of embodiment. The flowchart which shows the procedure of a 1st determination process. The flowchart which shows the procedure of a 2nd determination process.

  An example for carrying out the present invention will be described. FIG. 1 is a diagram illustrating the entire configuration of the embodiment. The photographing apparatus 200 is, for example, a digital still camera, generates color image data obtained by photographing the surface of a concrete structure, and stores the generated color image data in a memory.

  FIG. 2 is a diagram illustrating a hardware configuration of the concrete surface quality evaluation apparatus 100. The control unit 101 includes an arithmetic device such as a CPU (Central Processing Unit) and a storage device such as a ROM (Read Only Memory) and a RAM (Random Access Memory) (all not shown). The ROM stores firmware that describes the startup procedure of hardware and an OS (Operating System). The RAM is used for storing data when the CPU executes an operation.

  The storage unit 102 includes, for example, a hard disk storage device, and stores an OS, application programs, and the like. The communication unit 103 is, for example, a USB (Universal Serial Bus) terminal, communicates with the photographing apparatus 200 via a USB cable, and photographs color image data obtained by photographing the surface of the concrete structure by the photographing apparatus 200. Obtained from the device 200. An external IF (Interface) unit 104 is connected to an input device 110 such as a keyboard and a mouse, a display device 120 such as a liquid crystal panel, and a printing device 130 such as an ink jet printer.

  Next, surface defects will be described. Surface defects are classified into surface bubbles, cracks, lap lines (including cold joints and lap defects), sand lines, bean plates, surface peeling, and color unevenness. These surface defects exhibit a color different from the concrete background. Among surface defects, surface bubbles and cracks tend to be darker (closer to black) compared to wrapping lines (including cold joints and defective laying), sand lines, bean plates, surface peeling, and uneven color). (Hereinafter referred to as “other surface defects”, such as crease lines, sand lines, bean plates, surface peeling, and color unevenness). That is, the color range corresponding to surface bubbles and cracks, the color range corresponding to other surface defects, and the color range corresponding to the concrete background are different from each other. Since the color of each pixel constituting the color image data is generally expressed by the gradation of each color of R (red), G (green), and B (blue), in this embodiment, the three color levels of RGB are used. Depending on the tone, it is determined for each pixel which range of surface bubbles and cracks, other surface defects, and concrete background.

  FIG. 3 is a diagram showing a criterion for determining the surface layer quality. The figure is an example of R. R is represented by 256 gradations from 0 to 255. In this example, as the gradation value is larger, the average value of all pixels and the mode value of surface bubbles and cracks are obtained based on an image obtained by actually photographing a concrete structure. The average value of all the pixels is the average value of the gradation values of all the pixels, and a range having a certain width across the average value is determined as the concrete reference range. A pixel whose gradation value is within this range may not correspond to a surface defect.

  The mode value of the surface bubbles and cracks is calculated from the gradation values of the pixels that the user has visually determined as surface bubbles or cracks by displaying an image obtained by actually photographing the concrete structure on the display device. Alternatively, the mode value may be obtained from the gradation value of the shadow portion in the hole of the coin by photographing a 5-yen coin on the surface of the concrete structure. α is a value for adding color variation to the mode value, and is a value obtained by multiplying the mode value by a certain coefficient. For example, if the mode value is 100 and the coefficient is 0.3, α = 30 and mode value + α = 130. In this case, the range of R = 0 to 130 is determined as the surface bubble / crack range. Pixels whose gradation values are within this range may have surface bubbles or cracks.

Pixels whose gradation values do not fall within either the concrete reference range or the surface bubble / crack range may have other surface defects.
For G and B, as in the case of R, the determination standard for the surface layer quality is determined. However, the mode value of the surface bubbles and cracks and the average value of all pixels may be different for each color, and two colors or three colors may be equal. Also, a different α value may be set for each color. The storage unit 102 stores a concrete reference range and a surface bubble / crack range for each of R, G, and B.

  FIG. 4 is a diagram showing the contents of the pixel database 300 (hereinafter, pixel DB 300). The pixel DB 300 is stored in the storage unit 102. The pixel DB 300 has a record for each pixel, and each record includes “coordinate value”, “R gradation value”, “G gradation value”, “B gradation value”, “type”, and “label value”. Field corresponding to each item.

The “coordinate value” is a coordinate value of each pixel in the orthogonal coordinate system. “R gradation value”, “G gradation value”, and “B gradation value” are values representing R, G, and B in 256 gradations, respectively. As shown below, “type” represents the surface quality by a different number for each type.
0: No surface defects 1: Surface bubbles or cracks 2: Other surface defects 3: Surface bubbles 4: Cracks

  The “label value” is a label number assigned to the connected pixel. In this embodiment, a known labeling process is performed on pixels that are determined to have a surface defect, thereby extracting a connected pixel group composed of a plurality of adjacent pixels. Is given a unique label value.

  FIG. 5 is a flowchart illustrating a processing procedure according to the embodiment. The control unit 101 executes the following process according to the procedure described in the application program stored in the storage unit 102.

  In step S01, the user uses the photographing device 200 to photograph the surface of the concrete to be evaluated. Then, the color image data obtained by photographing the concrete surface is stored in the memory of the photographing apparatus 200.

  In step S02, color image data is taken into the concrete surface quality evaluation apparatus 100. Specifically, the user connects the photographing apparatus 200 and the concrete surface quality evaluation apparatus 100 with a USB cable, and transmits color image data from the photographing apparatus 200 to the concrete surface quality evaluation apparatus 100. The transmitted color image data is stored in the pixel DB 300.

  In step S03, the control unit 101 calculates an RGB average value of all pixel values, and specifies a concrete reference range. Specifically, the control unit 101 reads color image data from the pixel DB 300, calculates an average value of gradation values of all pixels for each of R, G, and B, and sets a concrete reference range based on the average value. Specify (see FIG. 3).

  In step S04, the control unit 101 specifies an RGB range (surface bubble / crack range) corresponding to surface bubbles or cracks. Specifically, an image based on the color image data is displayed on the display device 120, and the user designates a plurality of locations that are considered as surface bubbles or cracks using the input device 110 (mouse). Then, the control unit 101 extracts the R, G, and B tone values of the pixel located at the location designated by the user from the color image data, and the mode value of the tone value for each of R, G, and B Is identified. The control unit 101 multiplies the mode value by a coefficient to obtain α, and specifies the surface bubble / crack range (see FIG. 3).

  In step S05, the control unit 101 selects an evaluation target pixel. Specifically, the control unit 101 selects the first record in the pixel DB 300 as an evaluation target pixel.

  In step S06, the control unit 101 determines whether the evaluation target pixel is included in the surface bubble / crack range. Specifically, the control unit 101 reads out the R, G, and B gradation values of the evaluation target pixel from the pixel DB 300, and all the R, G, and B gradation values are included in the surface bubble / crack range. Is determined that the evaluation target pixel is included in the surface bubble / crack range (step S06: YES), and the process of the control unit 101 proceeds to step S10. On the other hand, when at least one gradation value of R, G, and B is not included in the surface bubble / crack range, it is determined that the pixel to be evaluated is not included in the surface bubble / crack range (step S06: NO). Then, the process of the control unit 101 proceeds to step S07.

  In step S10, the control unit 101 determines that there is a possibility that the evaluation target pixel has a surface bubble or a crack. In this case, the control unit 101 writes “1” in the type field corresponding to the pixel to be evaluated in the pixel DB 300.

  In step S07, the control unit 101 determines whether or not the evaluation target pixel is included in the concrete reference range. Specifically, when all the gradation values of R, G, and B are included in the concrete reference range, it is determined that the evaluation target pixel is included in the concrete reference range (step S07: YES), and the control unit 101 The process proceeds to step S08. On the other hand, when at least one gradation value of R, G, and B is not included in the concrete reference range, it is determined that the evaluation target pixel is not included in the concrete reference range (step S07: NO), and the control unit 101 The process proceeds to step S11.

  In step S08, the control unit 101 determines that the evaluation target pixel is not a surface defect. In this case, the control unit 101 writes “0” in the type field corresponding to the pixel to be evaluated in the pixel DB 300.

  In step S <b> 11, the control unit 101 determines that the evaluation target pixel may have another surface defect. In this case, the control unit 101 writes “2” in the type field corresponding to the evaluation target pixel in the pixel DB 300.

  In step S09, the control unit 101 determines whether or not all the pixels have been evaluated. When all the pixels have been evaluated (step S09: YES), the control unit 101 proceeds to the process of step S12 and does not evaluate them. If there is a pixel (step S09: NO), the process proceeds to step S05. In step S05, the control unit 101 selects a record next to the evaluation target pixel in the pixel DB 300 as a new evaluation target pixel, and executes the processes in and after step S06.

  In step S12, the control unit 101 assigns label values to all the pixels and writes them in the pixel DB 300 through a labeling process. By this process, a connected pixel group composed of a plurality of adjacent pixels is extracted, and a unique label value is assigned to each connected pixel group.

  With the above processing, the surface layer quality type of each pixel is determined as one of “0: no surface defect”, “1: surface bubbles or cracks”, and “2: other surface defects”. A unique label value is assigned to each connected pixel group. If the above process is completed, the control unit 101 executes a first determination process and a second determination process.

  FIG. 6 is a flowchart showing the procedure of the first determination process. The first determination process is a process that is executed for each connected pixel group that includes pixels that are determined to have surface bubbles or cracks in step S10 of FIG.

  In step S101, the control unit 101 determines whether or not the connected pixel group satisfies a density criterion. Specifically, the density standard is a threshold value of the number of pixels, and the control unit 101 determines that the step is performed when the number of pixels constituting the connected pixel group is less than the density standard (step S101: NO). Proceeding to step S105, it is determined that the connected pixel group is not a surface defect. This is because, when the number of pixels constituting the connected pixel group is very small (for example, the number of pixels is one), the connected pixel group may be an error in color image data. In this case, the control unit 101 overwrites “0” in the field of the type corresponding to the connected pixel group in the pixel DB 300. On the other hand, when the number of pixels constituting the connected pixel group is equal to or greater than the density standard (step S101: YES), the process of the control unit 101 proceeds to step S102.

  In step S102, the control unit 101 determines whether the shape of the connected pixel group matches the characteristics of the surface bubbles or the characteristics of the cracks. For example, the characteristic of the surface bubbles is that the connected pixel group has a planar shape, and the crack characteristic means that the connected pixel group has a linear shape. When the shape of the connected pixel group matches the characteristic of the surface bubble (step S102: surface bubble), the control unit 101 proceeds to the process of step S103, and the shape of the connected pixel group matches the characteristic of the crack ( In step S102: cracking), the process proceeds to step S104.

In step S103, the control unit 101 determines that the connected pixel group is a surface bubble, and overwrites “3” in the type field corresponding to the connected pixel group in the pixel DB 300.
In step S <b> 104, the control unit 101 determines that the connected pixel group is cracked, and overwrites “4” in the type field corresponding to the connected pixel group in the pixel DB 300.

  FIG. 7 is a flowchart showing the procedure of the second determination process. The second determination process is a process that is executed for each connected pixel group including pixels that are determined to have other surface defects in step S11 of FIG.

In step S201, the control unit 101 determines whether or not the connected pixel group satisfies a density criterion. Similar to the first criterion, the density criterion is a threshold value for the number of pixels, and the control unit 101 determines that the number of pixels constituting the connected pixel group is less than the density criterion (step S201: NO). Advances to the processing of step S203, determines that the connected pixel group is not a surface defect, and overwrites “0” in the field of the type corresponding to the connected pixel group in the pixel DB 300. On the other hand, when the number of pixels constituting the connected pixel group is equal to or greater than the density standard (step S201: YES), the process of the control unit 101 proceeds to step S202. Note that a value different from the density criterion in the first determination process may be set as the density criterion in the second determination process.
In step S202, the control unit 101 determines that the connected pixel group has another surface defect.

  Through the above processing, the surface quality of the concrete is determined as one of surface bubbles, cracks, and other surface defects from an image obtained by photographing the surface of the concrete structure. The control unit 101 causes the display device 120 to display an image that distinguishes surface bubbles, cracks, and other surface defects. For example, an image in which surface bubbles, cracks, and other surface defects are colored in different colors may be displayed, or an image in which different symbols are added to surface bubbles, cracks, and other surface defects may be displayed. Also good.

  According to this embodiment, the surface layer quality of a concrete structure can be determined for each type. Further, according to the present embodiment, it is possible to determine a plurality of types of surface quality included in a common color range for each type. In addition, the range of colors corresponding to the surface layer quality can be determined for each type of surface layer quality, taking into account the influence of various conditions such as the shooting conditions and concrete composition on the color of the surface layer quality.

<Modification>
The above embodiment may be modified as follows. A plurality of modified examples may be combined.
<First Modification>
In the above-described embodiment, an example in which surface bubbles and cracks are distinguished according to the shape of the connected pixel group has been described, but may be distinguished according to the size of the connected pixel group. For example, if the width of the connected pixel group in the two coordinate axis directions of the orthogonal coordinate system is less than a threshold value, it may be determined as a surface bubble, and if the width is equal to or greater than this threshold value, it may be determined as a crack. Alternatively, if the aspect ratio of the connected pixel group is less than a threshold value, it may be determined as a surface bubble, and if the aspect ratio is equal to or greater than this threshold value, it may be determined as a crack.

<Second Modification>
In the above embodiment, when all gradation values of R, G, and B are included in the surface bubble / crack range in step S06, it is determined that the evaluation target pixel is included in the surface bubble / crack range. When any one or two gradation values of R, G, and B are included in the surface bubble / crack range, it may be determined that the pixel to be evaluated is included in the surface bubble / crack range. The same applies to step S07. Moreover, since the colors of concrete and surface defects are close to achromatic colors, the values of R, G, and B are close to each other. Therefore, the color used for the determination may be limited to any one or two of R, G, and B.

<Third Modification>
In the above embodiment, an example is shown in which α is a value obtained by multiplying a mode value by a certain coefficient, but α may be a constant. In addition, α may be selected as a larger one of a value obtained by multiplying the mode value by a certain coefficient and a constant. For example, if the coefficient is 0.3, the constant is 10, and the mode value is 100, the value obtained by multiplying the mode value by the coefficient is 30, which is larger than the constant 10 and therefore α is 30. Is selected. Further, α may be selected as a smaller one of a value obtained by multiplying the mode value by a certain coefficient and a constant. Further, an offset value (for example, a constant between 0 and 5) may be added to α. Further, an average value may be used instead of the mode value.

<Fourth Modification>
The photographing apparatus 200 and the concrete surface quality evaluation apparatus 100 may be provided with a card slot for attaching and detaching a memory card, and color image data may be acquired via the memory card. Further, the color image data may be transmitted from the photographing apparatus 200 to the concrete surface quality evaluation apparatus 100 by wireless communication. Moreover, the concrete surface quality evaluation apparatus 100 may be a notebook computer or the like in which the photographing apparatus 200 is built.

DESCRIPTION OF SYMBOLS 100 Concrete surface quality evaluation apparatus, 101 Control part, 102 Storage part, 103 Communication part, 104 External IF part, 110 Input device, 120 Display apparatus, 130 Printing apparatus, 200 Imaging apparatus, 300 Pixel DB

Claims (5)

Obtaining means for obtaining color image data obtained by photographing the surface of the concrete structure;
Storage means for storing a color range corresponding to the surface layer quality for each type of surface layer quality of the concrete structure;
A determination unit that compares the color of each pixel included in the acquired color image data with the range of the color stored in the storage unit, and determines the surface layer quality of the concrete structure for each type; A concrete surface quality evaluation apparatus comprising: The determination unit determines a plurality of types of surface layer qualities indicated by pixels included in a common color range in the acquired color image data by distinguishing them according to the shape or size corresponding to the type. The concrete surface quality evaluation device described. The color range corresponding to the surface layer quality stored by the storage means is a color range determined based on an image obtained by photographing the surface of a concrete structure as a surface layer determination target in advance. Or the concrete surface quality evaluation apparatus of 2 or 2. The color range corresponding to the surface layer quality stored by the storage means is a color range determined based on a difference from the most frequent color in an image obtained by photographing the surface of the concrete structure that is the target of the surface layer quality determination. The concrete surface quality evaluation apparatus according to any one of claims 1 to 3. An acquisition step of acquiring color image data obtained by photographing the surface of the concrete structure;
Compare the content stored in the storage means for storing the color range corresponding to the surface layer quality for each type of surface layer quality of the concrete structure, and the color of each pixel included in the acquired color image data, A concrete surface quality evaluation method comprising: a determination step of determining surface quality of the concrete structure for each type.

Images