JP2018141663A - Condition measurement device, condition measurement system, and condition measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently measure and check conditions of a columnar structure.SOLUTION: A natural frequency of a utility pole 100 is calculated from a displacement of the utility pole 100 as determined by analyzing time-series image data obtained by photographing stripe pattern markers 110 attached to the utility pole 100. On the basis of the natural frequency, conditions of the utility pole 100 are determined. It is thereby possible to measure and check the conditions of the utility pole 100 without going to a site.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technique for determining the state of a structure.

  Social infrastructure facilities that were rapidly developed mainly around 1965-1975 are increasingly aging, and the need for inspection and repairs is increasing. Electricity / communication utility poles, road signs, street lights, traffic lights, power transmission lines / transmission towers, plant facilities such as factories are damaged due to corrosion of steel structures, cracks / peeling of concrete structures, etc. Before arriving, it has become an urgent task to grasp the condition by inspection.

  One means for grasping the state of the structure is full-field measurement that evaluates the displacement distribution of the structure from an image taken by a digital camera. For example, the deflection of a bridge can be measured by photographing a marker attached to the bridge with a digital camera with a fixed point and measuring the displacement of the marker attached location. The full-field measurement includes a digital image correlation method using a random pattern marker and a moire method using a regular pattern. The Moire method can measure displacement using the bridge truss structure itself as a marker.

  On the other hand, Non-Patent Document 1 discloses a pointing technique for photographing equipment capable of realizing an angular positioning accuracy of 1 μrad by a technique in which a piezoelectric element mechanism is incorporated in a motor drive. Using this technology, it is possible to perform angular positioning with an accuracy of 5 mm at a distance of 5 km from the photographic equipment, and the upper branch line (steel strand) connected to the top of the utility pole at a distance of 5 km is within the angle of view of the digital camera. The positioning accuracy is high enough to capture accurately. Furthermore, in the high-precision calibration device reported in Non-Patent Document 2, a device capable of angle calibration with an error of ± 0.5 seconds has been reported, and it is judged that there is sufficient technical maturity. is there.

"After the ex-post evaluation of the optical inter-satellite communication experimental satellite" KIRARI "(OICETS) project", [online], Japan Aerospace Exploration Agency, [December 15, 2016 search], Internet <URL: http: // www.mext.go.jp/b_menu/shingi/uchuu/reports/08031301/003.pdf> Tsukasa Watanabe, Tadashi Masuda, Makoto Sugaya, Hiroyuki Fujimoto, Tsuru Nakayama, “Development of high-precision calibration system for rotary encoder (1st report)-Calibration system and basic experiment-”, Journal of Japan Society for Precision Engineering, Japan Society for Precision Engineering, 2001, Vol. 67, No. 7, pp.1091-1095 “Results of investigation on non-electric pole measures”, [online], Ministry of Internal Affairs and Communications, [December 15, 2016 search], Internet <URL: http://www.soumu.go.jp/main_content/000308785.pdf>

  In order to know the state of the columnar structure, it was necessary for the inspector to go to the site where the columnar structure was located and carry out the inspection work. Since there are a great number of columnar structures installed in urban areas and suburbs (Non-patent Document 3), there is a problem that inspection must be performed efficiently in a short time.

  The present invention has been made in view of the above, and an object thereof is to efficiently measure and inspect the state of a columnar structure.

  The state measuring apparatus according to the first aspect of the present invention is an input means for inputting time-series image data obtained by photographing a predetermined pattern attached to a columnar structure, and is generated in the columnar structure from the time-series image data. Displacement calculating means for obtaining displacement, natural frequency calculating means for obtaining the natural frequency of the columnar structure from the displacement, and determining means for determining the state of the columnar structure based on the natural frequency It is characterized by that.

  A state measurement system according to a second aspect of the present invention acquires a three-dimensional position information of a photographing device for photographing a predetermined pattern attached to a columnar structure and the columnar structure from a map server, and includes the three-dimensional position information. Based on a movable base for positioning the angle of the photographing device so that the photographing device can photograph the predetermined pattern, input means for inputting time-series image data photographed by the photographing device, and the time-series image data from the time-series image data Displacement calculating means for obtaining displacement generated in the columnar structure, natural frequency calculating means for obtaining the natural frequency of the columnar structure from the displacement, and determining the state of the columnar structure based on the natural frequency And a state measuring device having a determining means.

  A state measuring method according to a third aspect of the present invention includes a step of inputting time-series image data obtained by photographing a predetermined pattern attached to a columnar structure, and a displacement generated in the columnar structure from the time-series image data. And a step of determining a natural frequency of the columnar structure from the displacement, and a step of determining a state of the columnar structure based on the natural frequency.

  According to the present invention, it is possible to efficiently measure and inspect the state of the columnar structure.

It is a whole lineblock diagram containing the state measuring device of this embodiment. It is a figure which shows the example of a two-dimensional digital pattern marker. It is a flowchart which shows the flow of a process of the state measurement apparatus of this embodiment. It is a graph which shows the change of the natural frequency when the crack generate | occur | produces in the utility pole. It is a graph which shows the change of natural frequency data in time series.

  FIG. 1 is an overall configuration diagram including a state measuring apparatus according to the present embodiment. The state measurement apparatus 1 shown in FIG. 1 inputs an image obtained by photographing a remote utility pole 100 with a digital camera 3 to which a telescope 4 is attached, analyzes the image to obtain the displacement of the utility pole 100, and obtains the obtained displacement as a natural frequency. Based on the obtained natural frequency, the state of the utility pole 100 (the presence or absence of cracks or the like) is determined. In addition, it is applicable not only to the utility pole 100 but also to other columnar structures such as street lamps.

  The state measurement apparatus 1 shown in FIG. 1 includes an input unit 11, a displacement calculation unit 12, a frequency calculation unit 13, and a determination unit 14. Each unit included in the state measurement device 1 may be configured by a computer including an arithmetic processing device, a storage device, and the like, and the processing of each unit may be executed by a program. This program is stored in a storage device included in the state measurement device 1, and can be recorded on a recording medium such as a magnetic disk, an optical disk, or a semiconductor memory, or provided through a network.

  The input unit 11 inputs time series image data obtained by photographing the utility pole 100.

  The displacement calculation unit 12 analyzes the input time-series image data and obtains the displacement generated in the utility pole 100. In the analysis of the displacement, a digital image correlation method or a moire fringe phase analysis method can be used according to the marker 110 attached to the utility pole 100.

  The utility pole 100 is provided with a striped pattern marker 110. The two-dimensional digital marker installed on the utility pole 100 may be any one that can measure the displacement of the utility pole 100 by image processing. In FIG. 2, the example of the two-dimensional digital pattern marker attached to the utility pole 100 is shown. In addition, when the branch line and suspension line installed in the upper part of the utility pole 100 are steel strands, the external shape of a steel strand can be observed as a striped pattern. A two-dimensional digital pattern may be projected onto the utility pole 100 using a projector or a laser scanner from a remote location.

  The frequency calculation unit 13 calculates the natural frequency of the utility pole 100 from the obtained displacement.

  The determination unit 14 determines the state of the utility pole 100 based on the natural frequency. For example, the state of the utility pole 100 is determined by comparing with a predetermined standard value, comparing with statistical data stored in advance, or detecting a change in statistical value of time-series data of natural frequency.

  The digital camera 3 is mounted on a movable table 5 having a biaxial angle positioning mechanism, and is disposed on a high place, for example, an upper part of a building in an urban area (communication / power transmission tower or high-rise building). As the angle positioning mechanism, an angle control technique of ± 0.92 μrad (at the time of capture) and ± 0.64 μrad (at the time of tracking) can be used by uniaxial control by the multilayer piezoelectric element described in Non-Patent Document 1.

  In order to fully utilize the high-accuracy angle positioning technique, it is necessary to select 57 / 100,000 for 360 degrees for the entire circumference and 16 / 100,000 for the elevation angle of 10 degrees even in the horizontal direction alone. In order to photograph a large number of remote utility poles 100, it is difficult to manually perform angular positioning of about 1 / 10,000,000 in two directions. Therefore, the 3D map server 2 is connected to the movable platform 5, the movable platform 5 is controlled based on the position information of the utility pole 100 obtained from the 3D map server 2, and the marker 110 attached to the utility pole 100 is attached to the digital camera 3. It should be within the angle of view. After the measurement of the utility pole 100 is completed, angle positioning is performed for the next neighboring inspection object, and the same inspection measurement is repeated continuously. Thereby, pointing to the inspection object on a street can be automated. The three-dimensional digital map held by the three-dimensional map server 2 is expected to be rapidly maintained in connection with the development of an autonomous driving vehicle.

  Next, a processing flow of the state measurement device according to the present embodiment will be described.

  FIG. 3 is a flowchart showing the flow of processing of the state measurement apparatus of this embodiment.

  The input unit 11 inputs time-series image data obtained by photographing the utility pole 100 (step S11). For example, image data obtained by photographing the utility pole 100 at time t1 and image data obtained by photographing the utility pole 100 at time t2 are input.

The displacement calculation unit 12 analyzes the image data to obtain the displacement (step S12). The displacement calculation unit 12 tracks and matches the pattern of the image data, and performs a process of searching for an area that is the optimum value of the normalized correlation coefficient from the time-series image data to deform the entire field of view, etc. A digital image correlation method for obtaining data is performed to determine the distortion and displacement of the utility pole 100. The method described in Reference Document 1 below may be used to determine strain and displacement.
Reference 1: Yoshiharu Morimoto, 2 others, “Displacement and strain distribution measurement by sampling moire method”, Journal of the Vacuum Society of Japan, Japan Vacuum Society, March 11, 2011, Vol. 54, No. 1, pp.32-38

The frequency calculator 13 calculates the natural frequency from the displacement (step S13). The natural frequency ω = 2πf and f = v / λ of the utility pole 100 can be calculated by obtaining the velocity v = dx / dt from the displacement x.
Reference 2: Nao Kunimatsu, “Series“ Corresponding to Complaints Concerning Vibration ”-2nd Basis of Vibration: Generation and Propagation of Vibration”, Journal of the Ministry of Internal Affairs and Communications, Pollution Control Committee, 2013 August 74th

  The determination unit 14 determines the state of the utility pole 100 based on the natural frequency (step S14). Hereinafter, an example of a state determination method by the determination unit 14 will be described.

  The first determination method is a method for determining abnormality by comparing the natural frequency with a standard value.

  FIG. 4 is a graph showing changes in the natural frequency when a crack occurs in the utility pole. The solid line indicates the natural frequency of the utility pole without cracks, and the dotted line indicates the natural frequency of the utility pole with cracks. As shown in the figure, the natural frequency decreases when a crack occurs in the utility pole. Therefore, the determination unit 14 determines that there is an abnormality in the utility pole 100 when the natural frequency decreases beyond the standard value based on the standard value.

  The second determination method is a method for determining abnormality by comparing the natural frequency with statistical data.

  For example, artificially create cracks of different sizes in the power pole in advance, accumulate data on the amount of change in the natural frequency of the power pole, and change from the accumulated data on the amount of change in the natural frequency. An amount is selected, and abnormality is determined based on the amount of change. A correlation function is obtained by performing regression analysis on a large number of data, and abnormality is determined using the correlation function.

  The third determination method is a method for determining abnormality based on time-series data of natural frequencies.

  As shown in FIG. 5, it is determined that there is an abnormality when a predetermined period of time-series natural frequency data or a predetermined number of statistical values change beyond a threshold value. For example, the statistical values of the data at 10 points before and after the natural frequency has changed greatly are obtained and compared, and if the difference between the statistical values is greater than or equal to the threshold value, it is determined as abnormal.

  As described above, according to the present embodiment, time-series image data obtained by photographing the stripe-shaped pattern marker 110 applied to the utility pole 100 is input, and the input time-series image data is analyzed to be generated in the utility pole 100. The state of the utility pole 100 is measured and checked without going to the site by calculating the natural frequency of the utility pole 100 from the obtained displacement and determining the state of the utility pole 100 based on the natural frequency. can do. It is only necessary to go to the site and perform detailed inspection / repair / renewal if necessary as a result of the measurement / inspection.

  According to this embodiment, the movable base 5 to which the digital camera 3 is attached is controlled based on the position information obtained from the 3D map server 2, and the marker 110 attached to the utility pole 100 is within the angle of view of the digital camera 3. By storing, pointing to the inspection object can be automated.

In addition, if the state measuring device of this embodiment can be installed near the tower of Tokyo Sky Tree, which uses the Kanto wide area (radius 50-100 km) as a broadcasting area for terrestrial digital broadcasting, it is within the living area of a population of 30 million people. There is a possibility of measuring and checking the huge columnar social infrastructure facilities in the area. The number of utility poles under Tokyo is about 1.1 million. Among these, even if the radius is limited to 30 km (2800 km ² ), which can be measured and checked even when the atmospheric condition is not optimal for observation, 5 to 600,000 can be measured and checked with the state measuring apparatus of this embodiment. Exists. Including the Saitama, Chiba, and Kanagawa areas, 2 million or more can be measured and inspected. Even if 90% of objects that cannot be observed due to the shadows of buildings are excluded, 200,000 or more can be inspected and measured. Is done. Furthermore, the number of utility poles in Japan is approximately 12 million, and it is estimated that more than 1 million measurement and inspection can be performed if measurement and inspection devices can be installed at the same density as described above. In addition to this, it is considered that a large number of equipment state measurements can be performed by applying the state measurement method according to the present invention to road signs, street lights, traffic lights, power transmission lines and power transmission towers, and the like.

DESCRIPTION OF SYMBOLS 1 ... State measuring apparatus 11 ... Input part 12 ... Displacement calculation part 13 ... Frequency calculation part 14 ... Determination part 2 ... Three-dimensional map server 3 ... Digital camera 4 ... Telescope 5 ... Movable stand 100 ... Electric pole 110 ... Marker

Claims (6)

An input means for inputting time-series image data obtained by photographing a predetermined pattern attached to the columnar structure;
A displacement calculating means for obtaining a displacement generated in the columnar structure from the time-series image data;
A natural frequency calculating means for obtaining a natural frequency of the columnar structure from the displacement;
Determination means for determining the state of the columnar structure based on the natural frequency;
A state measuring device comprising:   The state measuring apparatus according to claim 1, wherein the determination unit determines the state of the columnar structure by comparing the natural frequency with a standard value. Comprising storage means for storing statistical data of the natural frequency of the columnar structure;
2. The state measuring apparatus according to claim 1, wherein the determination unit determines the state of the columnar structure by comparing the natural frequency obtained by the natural frequency calculation unit and the statistical data. . Storage means for storing time-series data of the natural frequency of the columnar structure;
The state measuring apparatus according to claim 1, wherein the determination unit determines the state of the columnar structure based on a change amount of a statistical value of the time series data of a predetermined period or a predetermined number. A photographing device for photographing a predetermined pattern attached to the columnar structure;
A movable base that obtains three-dimensional position information of the columnar structure from a map server, and performs angle positioning of the photographing apparatus so that the photographing apparatus can photograph the predetermined pattern based on the three-dimensional position information;
Input means for inputting time-series image data photographed by the photographing apparatus, displacement calculation means for obtaining a displacement generated in the columnar structure from the time-series image data, and a natural frequency of the columnar structure from the displacement. A natural frequency calculating means to be obtained, a state measuring device having a determining means for determining the state of the columnar structure based on the natural frequency;
A state measurement system comprising: Inputting time-series image data obtained by photographing a predetermined pattern attached to the columnar structure;
Obtaining a displacement occurring in the columnar structure from the time-series image data;
Obtaining a natural frequency of the columnar structure from the displacement;
Determining the state of the columnar structure based on the natural frequency;
The state measuring method characterized by having.

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