Rebar condition determination method

Abstract

To provide a method for determining a state of a reinforcement which can minutely determine an arrangement state of a plurality of reinforcements.SOLUTION: A method for determining a state of a reinforcement includes: a first step of applying linear light 31, 32, and 33 extending in a direction X to different positions in the direction X of five reinforcements 2 lining in a direction Y (step S1); a second step of acquiring an image of the five reinforcements 2 on which the linear light 31, 32, and 33 is being applied (step S3); and a third step of determining an arrangement state of a reinforcement group 2G on the basis of a relationship of images 310, 320, and 330 of the linear light 31, 32, and 33 in the acquired image (step S5, step S6).SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for determining the condition of reinforcing bars. [Background technology]

[0002] BACKGROUND ART Conventionally, techniques for counting the number of long rod-shaped objects such as reinforcing bars while they are being transferred to a processing device or the like are known, for example, from Patent Documents 1 to 3.

[0003] Patent Document 1 describes a method of measuring the number of steel bars by irradiating a straight laser beam onto the steel bars as they are being transported, photographing the crescent-shaped laser trajectory formed on the surface of the steel bars by the irradiation with a camera, and processing the photographed image.

[0004] Patent document 2 describes a method in which the reflected light from multiple round rods arranged on a conveying table is photographed when irradiated with light, the reflected light contained in the photographed image is extracted using multiple extraction sensitivities, the number of reflected light beams at each extraction sensitivity is counted, and the maximum number of reflected light beams at each extraction sensitivity is determined to be the number of round rods.

[0005] Patent document 3 describes a method in which an optical sensor equipped with an emitting unit and a receiving unit is moved in the direction of arranging multiple elongated bodies, and the movement distance of the optical sensor is measured only when the receiving unit receives reflected light from the elongated bodies, and the measured movement distance is divided by the width of the elongated bodies to determine the number of elongated bodies. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 9-305737 [Patent Document 2] Patent No. 5077093 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-182172 Summary of the Invention [Problem to be solved by the invention]

[0007] When transferring reinforcing bars to processing equipment such as a reinforcing bar cutting machine or a reinforcing bar bending machine, the reinforcing bars need to be transferred in a state suitable for processing by the processing equipment. In order to process the reinforcing bars appropriately, it is necessary to determine, for example, whether the number of reinforcing bars is appropriate, whether the posture of the reinforcing bars is appropriate, whether the types of reinforcing bars are consistent, etc. According to Patent Documents 1-3, it is possible to determine the number of reinforcing bars, but it is difficult to determine the condition of the reinforcing bars in more detail.

[0008] An object of the present invention is to make it possible to determine in detail the condition of multiple placed reinforcing bars. [Means for solving the problem]

[0009] The techniques of the present disclosure are as follows. [1] A first step of simultaneously irradiating a plurality of linear lights extending in a first direction onto a plurality of positions in a second direction perpendicular to the first direction of each of a plurality of reinforcing bars arranged in a first direction; A second step of acquiring photographed images of the plurality of reinforcing bars irradiated with the plurality of linear light beams; and a third step of determining the arrangement state of the plurality of reinforcing bars based on the relationship between the images of the plurality of linear lights irradiated at each of the plurality of positions included in the photographed image. 、 the image includes an arc-shaped image corresponding to each of the plurality of reinforcing bars, In the third step, The inclination of each axis of the plurality of reinforcing bars is determined as the arrangement state of the plurality of reinforcing bars; determining an inclination of the axis of the reinforcing bar based on the positions of the arc-shaped images for each of the plurality of positions corresponding to the same reinforcing bar; In the captured image, a reference line indicating a position where the linear light would be captured if the plurality of reinforcing bars were not present is set for each image, and the position of the arc-shaped image in the direction in which the reference line extends at a point in the arc-shaped image farthest from the reference line is determined as the position of the arc-shaped image. Method for determining the condition of rebar.

[0010] [2] [1] The reinforcing bar condition determination method according to In the third step, the inclination of the axis of each of the plurality of reinforcing bars is determined as the arrangement state of the plurality of reinforcing bars.

[0011] [3] [2] The reinforcing bar condition determination method according to the image includes an arc-shaped image corresponding to each of the plurality of reinforcing bars, In the third step, the tilt of the axis of the reinforcing bar is determined based on the position of the arc-shaped image for each of the plurality of positions corresponding to the same reinforcing bar.

[0012] [4] [3] The reinforcing bar condition determination method according to In the third step, a reference line is set for each captured image to indicate the position where the linear light would be captured if the multiple reinforcing bars were not present, and the position of the arc-shaped image in the direction in which the reference line extends at the point in the arc-shaped image farthest from the reference line is determined to be the position of the arc-shaped image. [Effects of the Invention]

[0013] According to [1], linear light is irradiated at multiple positions along the longitudinal direction of the rebar, and images of the light irradiated at each position are acquired. By determining the relationship between the images acquired in this way, for example, the similarity of the shape and position of the images acquired at each position, it is possible to determine the placement state of the rebar, which is difficult to determine from a single image.

[0014] According to [2], since the inclination of the axis of the reinforcing bar can be determined, it is possible to prevent the start of processing when the inclination is not suitable for processing. In other words, it is possible to start processing the reinforcing bar with an inclination suitable for processing.

[0015] According to [3], for example, if the positions of the arc-shaped images at multiple positions corresponding to the same rebar are consistent, it can be determined that the inclination of the axis of the rebar is acceptable, and if the positions of the arc-shaped images at multiple positions corresponding to the same rebar are inconsistent, it can be determined that the inclination of the axis of the rebar is unacceptable. In this way, the inclination of the axis of the rebar can be easily and accurately determined based on the difference in the positions of the arc-shaped images.

[0016] According to [4], the inclination state of the axis of the reinforcing bar can be determined with high accuracy. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a perspective view showing a schematic configuration of a reinforcing bar processing facility 100. FIG. [Figure 2] 10 is a diagram showing a schematic example of an image IMG obtained by photographing a group of reinforcing bars 2G irradiated with linear light beams 31, 32, and 33 using a photographing device 4. FIG. [Figure 3] 10 is a flowchart for explaining the operation of the processor of the control device when determining the inclination state of the reinforcing bar 2. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, a reinforcing bar processing facility capable of realizing one aspect of the present invention will be described with reference to the drawings.

[0019] Fig. 1 is a perspective view showing a schematic configuration of a reinforcing bar processing facility 100. The reinforcing bar processing facility 100 includes a conveying unit 1 having a conveying surface 1A that conveys a group of reinforcing bars 2G consisting of a plurality of reinforcing bars 2 (five reinforcing bars in the example of Fig. 1) toward a reinforcing bar processing machine (such as a cutting machine or a bending machine) not shown, a light source device 3, a photographing device 4, and a control device (not shown).

[0020] Hereinafter, the direction in which the reinforcing bar group 2G is conveyed by the conveying unit 1 will be referred to as direction X, the direction from upstream to downstream in the conveying direction within direction X will be referred to as direction X1, and the direction opposite direction X1 will be referred to as direction X2. Furthermore, the direction perpendicular to direction X and perpendicular to conveying surface 1A will be referred to as direction Z, and the direction perpendicular to direction X and parallel to conveying surface 1A will be referred to as direction Y. One of the directions Y will be referred to as direction Y1, and the other of the directions Y will be referred to as direction Y2.

[0021] The reinforcing bars 2 are long rod-shaped bodies such as round steel bars or deformed reinforcing bars, and are placed on the conveying surface 1A so that their radial direction (width direction) coincides with direction Y, in other words, so that their longitudinal direction coincides with direction X. The five reinforcing bars 2 that make up the reinforcing bar group 2G are arranged side by side in direction Y on the conveying surface 1A. In this embodiment, direction Y constitutes a first direction, and direction X constitutes a second direction that is perpendicular to the first direction.

[0022] The light source device 3 irradiates the reinforcing bar group 2G placed on the conveying surface 1A with linear light (hereinafter referred to as linear light) extending in direction Y. The light source device 3 irradiates the reinforcing bar group 2G with linear light at each of a plurality of positions in direction X (three positions in the example of FIG. 1). The irradiation angle of the linear light is not particularly limited, but if the state in which the traveling direction of the linear light coincides with direction Z is defined as an irradiation angle of 0 degrees and the state in which the traveling direction of the linear light coincides with direction X is defined as an irradiation angle of 90 degrees, then the irradiation angle is set to, for example, a value greater than 0 degrees and less than 90 degrees.

[0023] 1 shows linear light beams 31, 32, and 33 as linear light beams emitted from light source device 3, which are emitted at different positions in direction X on conveyance plane 1A. The light source that generates the linear light beams may be a laser light source, an LED (Light-Emitting Diode) light source, a halogen lamp, a fluorescent lamp, or an incandescent lamp. When linear light beams 31, 32, and 33 are respectively irradiated onto reinforcing bar group 2G, irradiation lines 31A, 32A, and 33A that follow the shape of the outer circumferential surface of each reinforcing bar 2 are formed at the intersections between the outer circumferential surface of each reinforcing bar 2 in reinforcing bar group 2G and each linear light beam.

[0024] The photographing device 4 includes an imaging element such as a CCD image sensor or a CMOS image sensor, and is positioned so as to be able to photograph at least the area of ​​the reinforcing bar group 2G placed on the conveying surface 1A that is irradiated with the linear light beams 31, 32, and 33. The optical axis of the photographing optical system included in the photographing device 4 is preferably positioned so as to intersect with the traveling direction of each of the linear light beams 31, 32, and 33.

[0025] The control device includes a processor such as a CPU and a memory, and is configured, for example, as a personal computer. The control device is connected to the light source device 3 and the photographing device 4 so that they can communicate with each other. The processor of the control device controls the light source device 3 and the photographing device 4. The control device and the photographing device 4 may be provided in the same housing. The processor of the control device acquires, from the photographing device 4, an image obtained by photographing the reinforcing bar group 2G in a state where the linear light 31, 32, and 33 is irradiated, and determines the arrangement state of the reinforcing bar group 2G based on this photographed image.

[0026] FIG. 2 is a diagram schematically illustrating an example of a captured image IMG obtained by capturing a group of reinforcing bars 2G illuminated with linear light beams 31, 32, and 33 using a camera 4. The coordinates of each pixel constituting the captured image IMG are defined by a combination of a position in the X direction and a position in the Y direction. The captured image IMG shown in FIG. 2 illustrates a state in which only the images of the linear light beams 31, 32, and 33 have been extracted by applying a filter process or the like (i.e., the image has been processed so that images corresponding to the five reinforcing bars 2 and the conveying unit 1 are not included). Filtering is not essential. For example, by sufficiently increasing the illuminance of the linear light beams 31, 32, and 33 or adjusting the color, it is possible to identify the positions of the images of the linear light beams 31, 32, and 33 from the captured image IMG, which includes images of the reinforcing bars 2 and the conveying unit 1, and images of the linear light beams 31, 32, and 33 illuminated on the reinforcing bars 2.

[0027] As shown in Figure 2, the captured image IMG includes an image 310 of linear light 31 irradiated onto the reinforcing bar group 2G and the conveying unit 1, an image 320 of linear light 32 irradiated onto the reinforcing bar group 2G and the conveying unit 1, and an image 330 of linear light 33 irradiated onto the reinforcing bar group 2G and the conveying unit 1.

[0028] When linear light is irradiated onto the surface of the rebar 2, the brightness of the captured image of the linear light is highest at the top of the rebar 2 (the part opposite in direction Z from the bottom part that abuts against the conveying surface 1A) and decreases as it approaches the bottom of the rebar 2. In addition, the brightness of the captured image of linear light that enters the gaps between the rebars 2 is lower than the brightness of the captured image of linear light that enters the rebar 2 itself.

[0029] In this embodiment, as an example, only portions of the images of the linear light 31, 32, and 33 included in the captured image IMG that have brightness equal to or greater than a predetermined threshold value are extracted. As a result, an image 310 included in the captured image IMG includes five arc-shaped images 31a spaced apart in the direction Y and a linear image 31b that is shifted in the direction X2 from the five arc-shaped images 31a. The arc-shaped images 31a are obtained by photographing the linear light 31 irradiated onto the outer peripheral surfaces of the five rebars 2, and are obtained corresponding to each of the five rebars 2. The linear image 31b is obtained by photographing the linear light 31 irradiated onto an empty area of ​​the conveyance surface 1A adjacent to the rebar group 2G in the direction Y2.

[0030] Similarly, image 320 included in captured image IMG includes five arc-shaped images 32a spaced apart in direction Y, and linear image 32b positioned offset in direction X2 from the five arc-shaped images 32a. The arc-shaped images 32a are obtained by capturing an image of linear light 32 irradiated onto the outer peripheral surfaces of each of the five rebars 2, and are obtained corresponding to each of the five rebars 2. The linear images 32b are obtained by capturing an image of linear light 32 irradiated onto the open area.

[0031] Similarly, image 330 included in captured image IMG includes five arc-shaped images 33a spaced apart in direction Y, and linear image 33b positioned offset in direction X2 from the five arc-shaped images 33a. The arc-shaped images 33a are obtained by capturing an image of linear light 33 irradiated onto the outer peripheral surfaces of each of the five rebars 2, and are obtained corresponding to each of the five rebars 2. The linear images 33b are obtained by capturing an image of linear light 33 irradiated onto the open area.

[0032] The processor of the control device determines the arrangement state of the reinforcing bar group 2G based on the relationship between images 310, 320, and 330 included in the captured image IMG. The relationship between images 310, 320, and 330 refers to, for example, the positional relationship between feature points (first vertex, second vertex, and third vertex described below) in the three images, the relationship between the numbers of those feature points, etc. The arrangement state of the reinforcing bar group 2G includes at least one of the total number of reinforcing bars 2 included in the reinforcing bar group 2G, the orientation of each reinforcing bar 2 included in the reinforcing bar group 2G, and the uniformity of the diameters of the reinforcing bars 2 included in the reinforcing bar group 2G. The orientation of the reinforcing bars 2 includes at least the inclination of the axis of the reinforcing bar 2 with respect to the direction X. A specific example of a method for determining the arrangement state of the reinforcing bar group 2G will be described below.

[0033] First, the processor of the control device sets a reference line 31L shown in FIG. 2 corresponding to image 310 in the captured image IMG, sets a reference line 32L shown in FIG. 2 corresponding to image 320, and sets a reference line 33L shown in FIG. 2 corresponding to image 330.

[0034] When linear light 31, 32, 33 is irradiated onto the conveying surface 1A and an image is taken with the photographing device 4 while no reinforcing bar group 2G is placed on the conveying surface 1A, the reference lines 31L, 32L, 33L are set at positions on the photographed image where the linear light 31, 32, 33 irradiated onto the conveying surface 1A is imaged.

[0035] Because the positional relationship between the conveying unit 1, the photographing device 4, and the light source device 3 is fixed, the coordinates of the reference lines 31L, 32L, and 33L can be determined in advance. However, the photographed image IMG also includes linear images 31b, 32b, and 33b corresponding to the photographed images of the linear light 31, 32, and 33 when the linear light 31, 32, and 33 are irradiated onto the conveying surface 1A without the rebar group 2G placed thereon. For this reason, the processor of the control device may set the reference lines 31L, 32L, and 33L as lines extending from the linear images 31b, 32b, and 33b, respectively, in the direction Y1.

[0036] Next, the processor of the control device determines the part of each of the five arc-shaped images 31a corresponding to the reference line 31L that is farthest from the reference line 31L in the direction X (hereinafter referred to as the first apex) as the apex of each of the five reinforcing bars 2 at the irradiation position of the linear light 31.

[0037] In addition, the processor of the control device determines the part of each of the five arc-shaped images 32a corresponding to the reference line 32L that is farthest from the reference line 32L in the direction X (hereinafter referred to as the second apex) as the apex of each of the five reinforcing bars 2 at the irradiation position of the linear light 32.

[0038] In addition, the processor of the control device determines the part of each of the five arc-shaped images 33a corresponding to the reference line 33L that is farthest from the reference line 33L in the direction X (hereinafter referred to as the third apex) as the apex of each of the five reinforcing bars 2 at the irradiation position of the linear light 33.

[0039] (Example of determining the posture of rebar 2) The processor of the control device 5 calculates the slope of a graph of the positions of the first, second, and third vertices in the three arc-shaped images 31a, 32a, and 33a corresponding to the same rebar 2, using a least-squares method or the like. If the difference between the magnitude (absolute value) of the slope and zero is equal to or less than a threshold value TH1 (i.e., if the magnitude of the slope is approximately zero), the processor of the control device 5 determines that the rebar 2 is positioned with its axis parallel to the direction X and in a posture suitable for processing. On the other hand, if the difference exceeds the threshold value TH1, the processor of the control device determines that the rebar 2 is positioned with its axis inclined with respect to the direction X to an extent that is unacceptable for processing and in a posture unsuitable for processing. The processor of the control device performs a similar determination for each rebar 2 in the rebar group 2G and displays the determination result on a display or the like.

[0040] (Example of determining the number of rebars 2) The processor of the control device compares the total number of first apexes, the total number of second apexes, and the total number of third apexes determined as described above, and, for example, if these all match, determines that total number as the total number of reinforcing bars 2 included in the reinforcing bar group 2G.

[0041] (Example of determining the overlap state or uniformity of diameter of rebar 2) The processor of the control device obtains the average value of the distance from the reference line 31L to each first apex, and determines whether there is a first apex (hereinafter referred to as a first specific apex) whose distance from the reference line 31L is greater than this average value by at least a threshold value TH2. The processor of the control device obtains the average value of the distance from the reference line 32L to each second apex, and determines whether there is a second apex (hereinafter referred to as a second specific apex) whose distance from the reference line 32L is greater than this average value by at least a threshold value TH2. The processor of the control device obtains the average value of the distance from the reference line 33L to each third apex, and determines whether there is a third apex (hereinafter referred to as a third specific apex) whose distance from the reference line 33L is greater than this average value by at least a threshold value TH2.

[0042] For example, if a specific rebar 2 out of five rebars 2 is resting on the boundary between two adjacent rebars 2, or if only a specific rebar 2 out of five rebars 2 has a large diameter, the distances from the reference lines 31L, 32L, 33L of the first apex, second apex, and third apex corresponding to this specific rebar 2 will greatly exceed the above average values.

[0043] If the processor of the control device determines that two or more of the first specific apex, the second specific apex, and the third specific apex exist, it determines that the reinforcing bars 2 are overlapping (the specific reinforcing bars 2 are in a position that is not suitable for processing) or that the reinforcing bar diameters of the reinforcing bar group 2G are not uniform (the reinforcing bar group 2G contains a mixture of reinforcing bars 2 with different diameters).If the processor of the control device determines that two or more of the first specific apex, the second specific apex, and the third specific apex do not exist, it determines that the reinforcing bars 2 are not overlapping or that the reinforcing bar diameters of the reinforcing bar group 2G are uniform.

[0044] 3 is a flowchart for explaining the operation of the processor of the control device when determining the inclination state of the reinforcing bars 2. The processor of the control device controls the light source device 3 to emit linear light beams 31, 32, and 33 (step S1). Next, the processor of the control device controls the photographing device 4 to photograph the reinforcing bar group 2G in a state where the linear light beams 31, 32, and 33 are irradiated (step S2).

[0045] When the photographing in step S2 is completed, the processor of the control device acquires photographed images from the photographing device 4 (step S3), and determines the positions of the first apex, second apex, and third apex of each reinforcing bar 2 from each of the images 310, 320, and 330 included in the acquired photographed images (step S4). Next, the processor of the control device determines the tilt state of that reinforcing bar 2 based on the positional relationship in direction Y of the first apex, second apex, and third apex corresponding to the same reinforcing bar 2 (step S5). The processor of the control device similarly performs the determination in step S5 for the other reinforcing bars 2 (step S6), and then outputs the determination results (step S7).

[0046] As described above, according to the reinforcing bar processing equipment 100 of this embodiment, linear light beams 31, 32, and 33 are irradiated onto multiple positions along the longitudinal direction of the reinforcing bar group 2G being transported by the transport unit 1, and the irradiated linear light beams 31, 32, and 33 are acquired as images 310, 320, and 330. The arrangement of the reinforcing bar group 2G can be determined in detail by determining the relationship between the images 310, 320, and 330 thus acquired, for example, the positional relationship and number relationship between the tops of the images 310, 320, and 330. In particular, by being able to determine the inclination of the axes of the reinforcing bars 2 contained in the reinforcing bar group 2G, processing of the reinforcing bars 2 can be started in a state suitable for processing, allowing appropriate processing to be performed. Furthermore, compared to a reference example in which a single linear light beam is irradiated onto the reinforcing bar group 2G and the arrangement of the reinforcing bar group 2G is determined based on images obtained by capturing the reinforcing bar group 2G in that state, the reinforcing bar processing equipment 100 makes it possible to determine the inclination of the reinforcing bars 2, which cannot be determined in the reference example. Furthermore, even when determining the number of reinforcing bars 2, whether or not the reinforcing bars 2 overlap, or whether or not the reinforcing bars 2 are a mixture of different types, the accuracy of the determination can be improved compared to the reference example by using images of linear light irradiated at multiple positions.

[0047] Furthermore, in this embodiment, reference lines 31L, 32L, and 33L are set corresponding to the images 310, 320, and 330, respectively, and the position of the direction Y of the top of each reinforcing bar 2 is determined at three positions in the longitudinal direction using the reference lines 31L, 32L, and 33L. By determining the position of the direction Y of the top of each reinforcing bar 2 using the reference lines in this manner, the position of the top of the reinforcing bar 2 can be determined with high accuracy, and the inclination state of the reinforcing bar 2 can be determined with high accuracy. Furthermore, by being able to determine the position of the top of the reinforcing bar 2, it is also possible to derive the diameter of the reinforcing bar 2, for example, from the relationship between the distance from the reference line to the first top, second top, or third top and the irradiation angle of the linear light.

[0048] Although one embodiment of the present invention has been described above, the present invention is not limited thereto and can be modified as appropriate within the scope of the present invention. For example, in the above description, three linear light beams 31, 32, and 33 are irradiated onto the reinforcing bar group 2G, but this is not limiting. The number of linear light beams irradiated from the light source device 3 may be two, or may be four or more.

[0049] Furthermore, for example, a configuration may be adopted in which the light source device 3 irradiates a single linear light onto a predetermined position in the direction X of the transport unit 1, and the photographing device 4 takes photographs multiple times at different times while the reinforcing bar group 2G is being moved in the direction X1, thereby obtaining photographed images including images of the linear light irradiated onto different positions in the direction X on the reinforcing bar group 2G. Alternatively, a configuration may be adopted in which the irradiation position of the linear light irradiated from the light source device 3 can be changed in the direction X, and the photographing device 4 takes photographs each time the irradiation position of the linear light is changed, thereby obtaining photographed images including images of the linear light irradiated onto different positions in the direction X on the reinforcing bar group 2G. As shown in Figure 1, a configuration in which linear light is projected onto multiple positions simultaneously to capture images allows for rapid determination of the placement state of the rebar group 2G. Furthermore, with the configuration in Figure 1, the positions of the camera device 4 and light source device 3 are fixed, eliminating the need to wait for them to move. This allows for rapid determination of the placement state of the rebar group 2G, and also simplifies and downsizes the equipment structure. By simplifying the equipment structure, the amount of work required to adjust the equipment can be reduced, enabling more efficient rebar processing. When the time required for determining the total number of reinforcing bars 2 contained in a reinforcing bar group 2G was compared between the method described in Patent Document 3 and the method of this embodiment, it was found that the method of this embodiment was able to determine the number at least 10 times faster than the method described in Patent Document 3. As such, the reinforcing bar processing equipment 100 of this embodiment has high advantages in terms of cost, installation space, efficiency of reinforcing bar processing, and accuracy of determining the arrangement state of the reinforcing bar group 2G. [Explanation of symbols]

[0050] 1A Conveying surface 1. Conveyor 2G Rebar group 2. Reinforced concrete 3 Light source device 4. Imaging equipment 31A, 32A, 33A irradiation lines 31L,32L,33L Reference line 31a, 32a, 33a Arc-shaped images 31b,32b,33b Linear image 31,32,33 Linear light 100 Rebar processing equipment 310,320,330 images IMG Photographed image

Claims

[Claim 1] A first step of simultaneously irradiating a plurality of linear lights extending in a first direction onto a plurality of positions in a second direction perpendicular to the first direction of each of a plurality of reinforcing bars arranged in a first direction; A second step of acquiring photographed images of the plurality of reinforcing bars irradiated with the plurality of linear light beams; and a third step of determining the arrangement state of the plurality of reinforcing bars based on the relationship between the images of the plurality of linear lights irradiated at each of the plurality of positions included in the photographed image, the image includes an arc-shaped image corresponding to each of the plurality of reinforcing bars, In the third step, The inclination of each axis of the plurality of reinforcing bars is determined as the arrangement state of the plurality of reinforcing bars; determining an inclination of the axis of the reinforcing bar based on the positions of the arc-shaped images for each of the plurality of positions corresponding to the same reinforcing bar; A rebar condition determination method in which a reference line indicating the position where the linear light would be photographed if the multiple rebars were not present is set for each captured image, and the position of the arc-shaped image in the direction in which the reference line extends at the point on the arc-shaped image farthest from the reference line is determined to be the position of the arc-shaped image.

Images