JP2020046330A - System and method for evaluating structure - Google Patents

Abstract

To precisely determine a state of a structure.SOLUTION: A structure evaluation system according to one embodiment includes: an acquisition unit for acquiring image data of a structure; and a determination unit for determining a state of the structure on the basis of the image data. The determination unit, (A) calculates displacements of at least one measurement point of the structure and of a reference point of the structure from the image data, (B) calculates a ratio of the displacement of each of the at least one measurement point and the displacement of the reference point as a relative displacement, and (C) determines the state of the structure on the basis of the relative displacement of each of the at least one measurement point.SELECTED DRAWING: Figure 2

Description

  One aspect of the present disclosure relates to a structure evaluation system and a structure evaluation method.

  Techniques for evaluating the state of a structure have been conventionally known. For example, Patent Literature 1 describes a stiffness measuring device that measures a stiffness distribution of a measurement target. This device includes a displacement calculator, a load estimator, and a stiffness calculator. The displacement calculation unit calculates a displacement distribution indicating a spatial displacement over time for each of a plurality of measurement points set as the measurement target using a plurality of captured images of the measurement target captured at a plurality of times. I do. The load estimating unit estimates a load distribution indicating a spatial distribution of a load applied to the measurement target over time using the plurality of captured images. The stiffness calculating unit calculates a stiffness distribution of the measurement target using the displacement distribution and the load distribution.

Japanese Patent No. 6322817

  However, since it is difficult to accurately estimate the load (external force) applied to the structure, it is difficult to evaluate the state of the structure using the above-described technique that assumes the load distribution. Therefore, it is desired to accurately determine the state of the structure.

  A structure evaluation system according to an aspect of the present disclosure includes an acquisition unit that acquires image data of a structure, and a determination unit that determines a state of the structure based on the image data, wherein the determination unit determines a state of the structure. The respective displacements of one or more measurement points and the reference point of the structure are calculated from the image data, and for each of the one or more measurement points, the ratio between the displacement of the measurement point and the displacement of the reference point is calculated as a relative displacement. Then, the state of the structure is determined based on the relative displacement of each of the one or more measurement points.

  A structure evaluation method according to an aspect of the present disclosure is a structure evaluation method executed by a computer system, wherein an obtaining step of obtaining image data of a structure, and determining a state of the structure based on the image data A sub-step of calculating respective displacements of one or more measurement points of the structure and a reference point of the structure from the image data, and determining the displacement of each of the one or more measurement points. The method includes the sub-step of calculating the ratio of the displacement of the measurement point to the displacement of the reference point as a relative displacement, and the sub-step of determining the state of the structure based on the relative displacement of each of the one or more measurement points.

  In such an aspect, the displacement of each measurement point of the structure is converted into a relative value using the displacement of the reference point, and the state of the structure is determined based on the relative value. According to this method, the state of the structure can be accurately determined without acquiring the load applied to the structure.

  According to an embodiment of the present disclosure, it is possible to accurately determine a state of a structure.

It is a figure which shows the example of a structure typically. It is a figure showing an example of the functional composition of the structure evaluation system concerning an embodiment. It is a flowchart which shows an example of operation | movement of the structure evaluation system in embodiment. It is a figure which shows an example of a deformation | transformation of a structure typically. It is a flowchart which shows an example of operation | movement of the structure evaluation system in embodiment. It is a figure showing an example of relative displacement distribution of a structure. It is a figure showing an example of a technique of judging a state of a structure. It is a flowchart which shows an example of operation | movement of the structure evaluation system in embodiment. FIG. 2 is a diagram illustrating an example of a hardware configuration of a computer used in the structure evaluation system according to the embodiment.

  Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements will be denoted by the same reference symbols, without redundant description.

  The structure evaluation system 10 according to the embodiment is a computer system that determines a state of a structure. The structure evaluation system 10 can determine a state for each of one or more structures.

  A structure is an artificial object composed of a plurality of members. Examples of the structure include a bridge, a utility pole, a steel tower, and a house, but the type of the structure to be evaluated is not limited at all. A bridge is a structure that supports a passage made without closing a lower space such as a river, a valley, a strait, or another passage. This passage may function as at least one of a traffic route and a transport route, for example, may function as a road, a railroad, a waterway, or a sidewalk. Examples of bridges include road bridges, water bridges, overpasses, railway bridges, and pedestrian bridges, but the type of bridge is not limited at all.

  The state of the structure refers to the state of the structure that changes with time. For example, the state of the structure may be the degree of deterioration of the structure. Deterioration of a structure means that the quality or performance of the structure is impaired over time. The fact that the structure has not deteriorated means that the structure is sound (that is, the quality or performance of the structure is maintained). Therefore, it can be said that determining whether or not the structure has deteriorated is substantially the same as determining whether or not the structure is sound.

  The structure evaluation system 10 acquires the image data of the structure, and determines the state of the structure based on the image data. Specifically, the structure evaluation system 10 sets a plurality of measurement points on the structure reflected in the image data, and calculates the displacement of each measurement point by analyzing the image data. The structure evaluation system 10 converts the displacement of each measurement point into a relative displacement, and determines the state of the structure based on the relative displacement.

  FIG. 1 is a diagram schematically illustrating an example of a structure whose state is determined by the structure evaluation system 10. In this figure, a bridge 80 and a steel tower 90 are shown as examples of structures. When determining the state of the bridge 80, the structure evaluation system 10 sets a plurality of measurement points 80a on one side or one side surface of the bridge girder of the bridge 80, and determines the state based on the relative displacement of each measurement point 80a. May be. When determining the state of the steel tower 90, the structure evaluation system 10 sets a plurality of measurement points 90a on one side or one side surface of the steel tower 90, and determines the state based on the relative displacement of each measurement point 90a. Is also good. The location of each measurement point is not limited, and may be determined based on an arbitrary policy.

  FIG. 2 is a diagram illustrating an example of a functional configuration of the structure evaluation system 10. The structure evaluation system 10 includes an acquisition unit 11, a determination unit 12, and an output unit 13 as functional elements.

  The acquisition unit 11 is a functional element that acquires image data of a structure. The image data is data indicating an image that can be visually recognized by being processed by a computer. The image format is not limited as long as the displacement of the structure at a certain point can be obtained. For example, the image may be a moving image, a set of a plurality of still images obtained by continuous shooting, or a set of still images of a plurality of frames extracted from the moving image. The acquisition unit 11 may extract still images of a plurality of frames from a moving image. The image data of a structure refers to image data of at least a part of the structure, and more specifically, an image of a part of the structure necessary to determine the state of the structure. Refers to data. For example, image data obtained by imaging the whole or almost the entire structure is used.

  The determining unit 12 is a functional element that determines the state of the structure by analyzing the image data acquired by the acquiring unit 11. The determination unit 12 sets a plurality of measurement points on the structure shown in the image data and calculates the displacement of each measurement point. In addition, the determination unit 12 selects one reference point from the plurality of measurement points. The determination unit 12 determines the relative displacement of each measurement point, and determines the state of the structure based on the plurality of relative displacements. In the present disclosure, the displacement refers to the amount of movement of the measurement point when the structure is deformed under a load, and the relative displacement refers to the ratio of the displacement of the measurement point to the displacement of the reference point. . The cause of the load applied to the structure is not limited at all. For example, the load may be caused by an arbitrary tangible object riding or hanging on the structure, or may be caused by a natural phenomenon such as wind or earthquake acting on the structure.

  The output unit 13 is a functional element that outputs a determination result obtained by the determination unit 12. The method of expressing the determination result is not limited. For example, the determination result may be expressed in two stages of “deteriorated” and “not degraded”, or “no deterioration”, “deterioration = low”, “deterioration = medium”, “deterioration = high” "May be expressed at three or more levels. Alternatively, the determination result may be represented by an arbitrary index, for example, a difference between the average values of two relative displacement distributions described later. Alternatively, the determination result may be represented using a graph or a graphic. In any case, the user of the structure evaluation system 10 can check the state of the structure by referring to the determination result, and can determine whether the structure should be reinforced or repaired.

  As shown in FIG. 2, image data of the structure is obtained by the camera 20. The camera 20 is an imaging device that captures an image of a structure to generate image data. The camera 20 may be constructed as a part of the structure evaluation system 10, or may be constructed as a component separate from the structure evaluation system 10. The camera 20 may be integrated with a computer constituting the structure evaluation system 10. The camera 20 may be fixedly installed at a position where the structure can be imaged, or may be brought to the observation position by a person every time photographing is performed if fixed point observation is possible. The camera 20 has a function of generating an image having a resolution that can detect a displacement of a structure. The image data is sent from the camera 20 to the image database 21 via the communication network or the recording medium, and is stored in the image database 21. Examples of the communication network include a mobile communication network, the Internet, and a WAN (Wide Area Network). Examples of the recording medium include an SD memory card and a USB memory. However, the communication network and the recording medium are not limited to these, and any method may be adopted.

  The image database 21 is a device (storage unit) that temporarily or permanently stores image data. The image database 21 may be constructed as a part of the structure evaluation system 10, or may be constructed as a component different from the structure evaluation system 10. The acquisition unit 11 can access the image database 21 and read out image data. The image database 21 is not an essential component, and the structure evaluation system 10 may receive image data directly from the camera 20.

  In one example, the image data of the structure is associated with the shooting date and time. Alternatively, the image data may be associated with a structure ID that is an identifier that uniquely specifies the structure. Alternatively, the image data may be associated with both the structure ID and the shooting date and time.

  As shown in FIG. 2, in one example, the displacement database 22 may be used. The displacement database 22 is a device (storage unit) that temporarily or permanently stores data relating to the relative displacement calculated by the structure evaluation system 10. The displacement database 22 may be constructed as a part of the structure evaluation system 10, or may be constructed as a computer system different from the structure evaluation system 10. In one example, the determination unit 12 accesses the displacement database 22, stores data relating to the relative displacement in the displacement database 22, and reads the data to determine the state of the structure.

  In one example, the relative displacement data may be associated with a shooting date and time. Alternatively, the determination result may be associated with the structure ID. Alternatively, the determination result may be associated with both the structure ID and the shooting date and time.

  The specific procedure for determining the state of the structure is not limited. Hereinafter, some examples of the determination will be described.

  An example of the process of determining the state of the structure based on the relative displacement distribution will be described with reference to FIGS. The relative displacement distribution is data indicating the frequency of appearance of the relative displacement at each stage within a certain limited period. FIG. 3 is a flowchart illustrating an example of a process of generating a relative displacement distribution as a process flow S1. FIG. 4 is a diagram schematically illustrating an example of a modification of the structure. FIG. 5 is a flowchart illustrating an example of the determination process using the relative displacement distribution as a process flow S2. FIG. 6 is a diagram showing an example of the relative displacement distribution. FIG. 7 is a diagram illustrating an example of a technique for determining the state of a structure. FIG. 3 and FIG. 5 both show processing for a certain structure.

  The structure evaluation system 10 generates a relative displacement distribution in one observation period. The observation period refers to the length of time during which the state of the structure is estimated to hardly change, in other words, the period during which the deterioration of the structure is not expected to progress. Therefore, it can be said that the observation period is a period that is very short compared to the service life of the structure. The specific length of the observation period is not limited, and may be set according to, for example, the type and characteristics of the structure. For example, the length of the observation period may be hours, days, weeks, months, or a year. The structure evaluation system 10 can obtain a relative displacement distribution for each of the plurality of measurement points by calculating the relative displacement at each of a plurality of measurement points in one observation period. In consideration of the life of the structure, the relative displacement distribution during one observation period can be said to be statistical data indicating the tendency of the structure to be displaced at a certain point in time. You can also.

  In step S101, the determination unit 12 sets one observation period. The start point and end point of the observation period may be set arbitrarily.

  In step S102, the determination unit 12 sets one measurement time point within the observation period. The measurement time point refers to a time point when a single displacement occurs in the structure. For example, when determining the state of a bridge, the measurement time point is the time during which only one object is passing through the bridge. Here, the object passing through the bridge is not limited, and may be, for example, a car, a bicycle, a train, a ship, a flying object, or a person.

  In step S103, the acquisition unit 11 acquires image data corresponding to the measurement time. The method for acquiring the image data is not limited. For example, the obtaining unit 11 may obtain the image data from the image database 21 or may receive the image data directly from the camera 20. In one example, the acquisition unit 11 may extract only a part necessary for measuring the displacement from the image data. The “portion necessary for measuring the displacement” may be a moving image for a certain time width, or may be a set of a plurality of still images continuously shot in the time width. When determining the state of the bridge, the acquisition unit 11 extracts only a portion obtained by imaging a scene where only one object passes, from the image data. When the object is a vehicle, since the displacement of the bridge increases as the weight of the passing vehicle increases, the acquisition unit 11 extracts from the image only a portion obtained by imaging a scene where one large vehicle such as a truck passes. Is also good. Using a known technique for detecting or estimating an object from an image, the acquisition unit 11 can automatically extract, from the image data, a screen in which one object passes through the bridge. Examples of the known techniques include template matching and deep learning, but techniques for detecting or estimating an object are not limited to these. The process of extracting such a specific scene from the image data is not essential. For example, the image data extracted by manual processing may be stored in the image database 21 in advance, and the acquisition unit 11 may acquire the edited image data.

  In step S104, the determination unit 12 sets a plurality of measurement points for the structure shown in the image data. The method of setting the measurement points is not limited, and may be set in consideration of, for example, the type, shape, and characteristics of the structure. For example, as shown in FIG. 1, the determination unit 12 can set a plurality of measurement points 80 a on the bridge 80 or set a plurality of measurement points 90 a on the steel tower 90. The distance between adjacent measurement points may be set arbitrarily. For example, the measurement points may be set at equal intervals, or the distance between the measurement points may vary.

  In step S105, the determination unit 12 calculates each displacement of the plurality of measurement points. The determination unit 12 can calculate the displacement of each measurement point during the passage of one object by analyzing the image data using a known technique such as a block matching method or a digital image correlation method. The block matching method is a method in which one of two images is divided into a plurality of blocks, and for each block, a corresponding position is searched for on the other image to obtain a displacement. The digital image correlation method is a method of calculating a displacement by comparing the position of a specific random pattern between two images. The determining unit 12 may apply a low-pass filter to the obtained displacement to remove a vibration component and obtain a static change of the measurement point. In this case, the displacement before applying the low-pass filter can be said to be a temporary displacement, and the value obtained by applying the low-pass filter can be said to be the displacement to be obtained. By using a low-pass filter, the displacement can be obtained more accurately. The displacement of each measurement point can change in the time width corresponding to the image data. The determination unit 12 obtains the maximum value or the average value of the displacement at each of the plurality of measurement points, and sets the maximum value or the average value as the displacement at the measurement point.

FIG. 4 is a diagram illustrating an example of the calculated displacement. More specifically, FIG. 4 illustrates the displacement at five measurement points 81 to 85 set on the bridge 80. STATUS This example is an object by the load produced when passing through the bridges 80, the measurement points 81,82,83,84,85 is displaced by _{x 1, x 2, x 3} , x 4, x 5 up to each Is shown. The determination unit 12 sets these values x ₁ , x ₂ , x ₃ , x ₄ , and x ₅ as displacement of each measurement point.

In step S106, the determination unit 12 selects one reference point from the plurality of measurement points. The method for selecting the reference point is not limited, and any method may be used. For example, the determination unit 12 may select a measurement point at which the calculated displacement is the largest as a reference point. It can be expected that the larger the displacement, the smaller the ratio of error. Therefore, by using the measurement point at which the maximum displacement is recorded as the reference point, it is possible to reduce the error of the relative displacement, and to accurately determine the state of the structure. In the example of FIG. 4, since the largest displacement x _3, the determination unit 12 may select the measurement point 83 as a reference point.

In step S107, the determination unit 12 calculates the relative displacement of each of the plurality of measurement points. As described above, the relative displacement is a ratio between the displacement of the measurement point and the displacement of the reference point. The determination unit 12 may set a value obtained by dividing the displacement of the reference point by the displacement of the measurement point as a relative displacement, or may set a value obtained by dividing the displacement of the measurement point by the displacement of the reference point as a relative displacement. Good. When the measurement point 83 is selected as the reference point in the example of FIG. 4, the determination unit 12 determines the relative displacements of the measurement points 81, 82, 83, 84, and 85 as x ₃ / x ₁ and x ₃ / x, respectively. _{2, x 3 / x 3,} x 3 / x 4, may be obtained with _x 3 / x _5. The relative displacement of the measurement point selected as the reference point is always 1.

  As shown in step S108, when there is another measurement time point to be processed within one observation period, the process proceeds to step S109, and the determination unit 12 determines the next measurement time point within the observation period. Set. Thereafter, the processing of steps S103 to S107 is executed for the measurement time point. On the other hand, if the relative displacement has been calculated for all the measurement points in the observation period, the process proceeds to step S110.

  In step S110, the determination unit 12 generates a relative displacement distribution for each measurement point in one observation period. However, since the relative displacement of the reference point is always 1, it is sufficient for the determination unit 12 to obtain the relative displacement distribution for each measurement point other than the reference point. The determination unit 12 may store data indicating the generated relative displacement distribution in the displacement database 22. The relative displacement distribution data may be represented by a set of individual relative displacements of individual measurement points. When the relative displacement distribution can be approximated by a normal distribution, the relative displacement distribution data at each measurement point may be represented by an average value, unbiased variance, and sample size.

  The structure evaluation system 10 generates the relative displacement distribution for each observation period by executing the processing flow S1 in each of the plurality of observation periods. The structure evaluation system 10 may periodically execute the processing flow S1. For example, the structure evaluation system 10 may acquire the relative displacement distribution every day if the observation period is several hours, may acquire it every month if the observation period is several weeks, and may acquire the relative displacement distribution for one year. May be acquired every year. The structure evaluation system 10 obtains the relative displacement distribution without changing the positions of the plurality of measurement points and the reference point in each observation period, and thereby can accurately capture a change in the structure over time.

  At any timing after obtaining the relative displacement distribution for a plurality of observation periods, the structure evaluation system 10 executes the processing flow S2.

  In step S201, the determination unit 12 acquires the relative displacement distribution in the reference period from the displacement database 22 as the first relative displacement distribution. In step S202, the determination unit 12 acquires the relative displacement distribution during the inspection period from the displacement database 22 as the second relative displacement distribution. The first relative displacement distribution is generated from image data (first image data) of the structure during the reference period, and the second relative displacement distribution is generated from image data (second image data) of the structure during the inspection period. It was done. The reference period refers to an observation period used as a reference for determining the state of the structure, and the inspection period refers to an observation period in which the state of the structure is to be known. The reference period and the inspection period may be arbitrarily determined, and may be specified by, for example, a user of the structure evaluation system 10. As an example, the reference period may be a period set at a time when the structure is known to be healthy. For example, the reference period may correspond to a time immediately after the structure has been constructed, or may correspond to a time after the structure has been regularly inspected.

  In step S203, the determination unit 12 determines the state of the structure by comparing the relative displacement distributions in both the reference period and the inspection period. The specific determination method is not limited, and the determination unit 12 can use an arbitrary method.

  As an example, the determination unit 12 may determine an average value of the relative displacement distribution for each of the reference period and the inspection period, and determine the state of the structure by comparing both average values. For example, the determination unit 12 can determine that the structure has deteriorated if there is a significant difference between the two average values, and can determine that the structure has not deteriorated if there is no significant difference. Alternatively, the determination unit 12 may set the difference between the two average values as the determination result.

  As shown in each graph of FIG. 6, for each of the measurement points 81, 82, 84, 85 of the bridge 80 (excluding the measurement point 83 which is a reference point), the relative displacement distribution 31 in the reference period and the relative displacement in the inspection period It is assumed that the distribution 32 is obtained. Here, the horizontal axis of the graph indicates displacement, which is a random variable, and the vertical axis indicates probability density. If there is no significant difference between the average values of these two relative displacement distributions, it is determined that the state of the bridge 80 during the inspection period is almost the same as that in the reference period, and that the bridge 80 has not deteriorated. Can be. On the other hand, if there is a significant difference between the average values of these two relative displacement distributions, it can be said that the state of the bridge 80 has changed significantly with the elapse of the period from the reference period to the inspection period. Can be determined. As an example, when the value obtained by dividing the displacement of the reference point that undergoes the largest displacement by the displacement of the measurement point is set as the relative displacement, the relative displacement distribution during the inspection period is more than the average value of the relative displacement distribution during the reference period. It can be said that there is a high probability that the vicinity of the measurement point having a small average value has deteriorated. As described above, for at least one measurement point, the determination unit 12 may set a difference between the average values between the reference period and the inspection period as a determination result.

  The determination unit 12 may verify whether or not there is a significant difference between the two average values by using Welch's t-test. Welch's t-test is a technique for testing whether the averages of two populations are equal. By using this method, even when the sample size differs between the reference period and the inspection period, the average value of the two periods can be compared. For example, even when the number of measurement points is different between the reference period and the inspection period because the two periods have different lengths, the average value can be appropriately compared. As a result, it is possible to accurately estimate a change in the structure with the passage from the reference period to the inspection period. Therefore, in one example, the time length may be different between the reference period and the inspection period, and the number of measurement points may be different between both periods.

ここで、

は第１の母集団の標本平均であり、

は第２の母集団の標本平均である。ｓ_１ ^２は第１の母集団の不偏分散であり、ｓ_２ ^２は第２の母集団の不偏分散である。ｎ_１は第１の母集団のサンプルサイズであり、ｎ_２は第２の母集団のサンプルサイズである。 In Welch's t-test, the statistic t is defined by the following equation (1).

here,

Is the sample mean of the first population,

Is the sample mean of the second population. s ₁ ² is the unbiased variance of the first population, and s ₂ ² is the unbiased variance of the second population. n ₁ is the sample size of the first population, and n ₂ is the sample size of the second population.

The degree of freedom ν is defined by the following equation (2).

  If Welch's t-test is used as it is, the determination unit 12 may determine that the structure has deteriorated even if the difference between the average values is small. In order to grasp a change that affects the performance of the structure, the determination unit 12 changes the average value (first average value) of the relative displacement distribution in the reference period by a given amount, and then changes the Welch t. A test may be performed. The amount of change in the first average value may be set on an arbitrary basis. For example, the amount of change may be set based on a criterion for determining how much the state of the structure has changed before the structure is considered to have deteriorated.

を加えてもよい。 More specifically, the amount of change may be set based on the rate of change α of the relative displacement. When this ratio α is used, the determination unit 12 changes the first average value to (1−α) times, and then changes the average value (second average value) of the relative displacement distribution during the inspection period. It is tested whether or not the alternative hypothesis that the value is smaller than the first average value holds. In addition, the determination unit 12 changes the first average value by (1 + α) times, and tests whether the alternative hypothesis that the second average value is larger than the changed first average value holds. . The determination unit 12 executes these two one-sided tests, determines that the structure is degraded when either of the two alternative hypotheses is satisfied, and determines that the structure is degraded when neither of the alternative hypotheses is satisfied. You may determine that it has not deteriorated. For example, when the ratio α is set to 0.1, the determination unit 12 determines the structure when the average value of the relative displacement distribution of the structure changes by more than 10% from the reference period to the inspection period. It is determined that the state of the object has changed significantly (for example, it is determined that the structure has deteriorated). The determination unit 12, a first average value, instead of (1 ± alpha) multiplied, in all samples x _s of the reference period

May be added.

  FIG. 7 shows an example of Welch's t-test using the ratio α. This figure shows that the average value (first average value) of the relative displacement distribution 41 during the reference period is changed by (1−α) times, and then the average value (second average value) of the relative displacement distribution 42 during the inspection period. Is compared with the first average value after the change. In this example, the alternative hypothesis holds because the second average value is smaller than the changed first average value. Therefore, the determination unit 12 determines that the structure is deteriorated.

When the ratio α is used, the determination unit 12 obtains the two statistics t ₁ and t ₂ by the following equations (3) and (4).

  The determination unit 12 performs two one-sided tests for each measurement point other than the reference point, using the above-described method to which Welch's t-test is applied. When there are two or more measurement points other than the reference points, the determination unit 12 determines the state of the structure after comprehensively considering the test results at the individual measurement points by an arbitrary method. Is also good. For example, the determination unit 12 determines that the structure is deteriorated when a significant difference occurs in the average value at at least one measurement point, and determines that the significant difference does not occur at any measurement point. May be determined that the structure is not deteriorated. Alternatively, the determination unit 12 determines that the structure is deteriorated when a significant difference occurs in the average value at a plurality of measurement points, and determines that the number of measurement points at which the significant difference has occurred is one or less. In some cases, it may be determined that the structure has not deteriorated. Alternatively, when a significant difference occurs in the average value at n (n> 1) or more measurement points, the determination unit 12 determines that the structure is deteriorated, and performs the measurement in which the significant difference has occurred. If the number of points is less than n, it may be determined that the structure has not deteriorated. Alternatively, the determination unit 12 may set a difference between the changed first average value and the changed second average value for at least one measurement point as the determination result.

  In step S204, the output unit 13 outputs a determination result. The method of outputting the determination result is not limited. For example, the output unit 13 may store the determination result in a predetermined database, transmit it to another computer, or display it on a monitor.

  Step S103 is an example of an acquisition step, and steps S104 to S107 and S110 are examples of a determination step. Steps S201 to S203 are an example of a determination step. According to the processing flows S1 and S2, the change in the relative displacement with the passage of time is considered and the history thereof is statistically processed, so that the state of the structure can be accurately determined.

  When executing the processing flows S1 and S2, the structure evaluation system 10 does not need to temporarily store the data of the relative displacement distribution in the displacement database 22. For example, the structure evaluation system 10 may generate the relative displacement distribution for each of the reference period and the inspection period, and then execute the processing flow S2 using the relative displacement distribution without using the displacement database 22.

  FIG. 8 is a flowchart illustrating an example of a process for determining the state of the structure without using the relative displacement distribution as a process flow S3.

  The processing of steps S301 to S305 is the same as the processing of steps S103 to S107 in the processing flow S1. In step S301, the acquisition unit 11 acquires image data corresponding to any one measurement time point. The acquisition unit 11 may extract only a portion necessary for measuring the displacement from the image data, or may acquire edited image data in which the portion is manually extracted. In step S302, the determination unit 12 sets a plurality of measurement points for the structure shown in the image data. In step S303, the determination unit 12 calculates the displacement of each of the plurality of measurement points by analyzing the image data. Since the displacement of each measurement point can change in the time width corresponding to the image data, the determination unit 12 obtains the maximum value or average value of the displacement at each measurement point for each of the plurality of measurement points, and determines the maximum value or average value. The value is set as the displacement at the measurement point. In step S304, the determination unit 12 selects one reference point from a plurality of measurement points. In step S305, the determination unit 12 calculates the relative displacement of each of the plurality of measurement points.

  In step S306, the determination unit 12 determines the state of the structure by comparing those relative displacements with a given threshold. The setting method of the threshold value is not limited. For example, the threshold value may be a single value common to a plurality of measurement points, or may be set individually for each measurement point. The specific value of the threshold is not limited, and may be a fixed value such as 2, for example. Alternatively, the determination unit 12 may use the amount of change (for example, 10%) from the relative displacement at the reference time point, which is another measurement time point, as the threshold. This processing is based on the premise that the structure evaluation system 10 performs steps S301 to S305 on the image data corresponding to the reference time to obtain the relative displacement at the reference time as the first relative displacement. After that, the structure evaluation system 10 executes steps S301 to S305 on the image data corresponding to the inspection time to obtain the relative displacement at the inspection time as the second relative displacement. The determination unit 12 determines the state of the structure at the time of inspection by comparing the second relative displacement with the first relative displacement. For example, the determination unit 12 determines that the structure has deteriorated when the second relative displacement has changed from the first relative displacement by a threshold value or more, and otherwise determines that the structure has not deteriorated. You may.

  The determining unit 12 determines that the structure is degraded when the relative displacement is equal to or greater than the threshold value at at least one measurement point, and degrades the structure when the relative displacement is less than the threshold value at any measurement point. It may be determined that it has not been done. Alternatively, the determination unit 12 determines that the structure is deteriorated when the relative displacement is equal to or greater than the threshold value at a plurality of measurement points, and determines that the number of measurement points having the relative displacement equal to or greater than the threshold value is 1 or less. May be determined that the structure has not deteriorated. Alternatively, when the relative displacement is equal to or greater than the threshold value at n (n> 1) or more measurement points, the determination unit 12 determines that the structure is degraded, and determines the measurement point having the relative displacement equal to or greater than the threshold value. If the number is less than n, it may be determined that the structure has not deteriorated.

  In step S307, the output unit 13 outputs a determination result. This process is the same as step S204 in the process flow S2.

  Step S301 is an example of an acquisition step, and steps S302 to S306 are an example of a determination step. In the processing flow S3, the state of the structure can be easily determined using only the relative displacement at one measurement time point. In addition, since it is not necessary to store the history of the relative displacement in a plurality of observation periods, it is possible to reduce the amount of storage devices such as a database and a memory.

  The block diagram used in the description of the above-described embodiment shows blocks in functional units. These functional blocks (components) are realized by an arbitrary combination of at least one of hardware and software. In addition, a method of implementing each functional block is not particularly limited. That is, each functional block may be realized using one device physically or logically coupled, or directly or indirectly (for example, two or more devices physically or logically separated from each other). , Wired, wireless, etc.), and may be implemented using these multiple devices. The functional block may be realized by combining one device or the plurality of devices with software.

  Functions include judgment, decision, judgment, calculation, calculation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, deemed, Broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, assigning, but not limited to these I can't. For example, a functional block (configuration unit) that causes transmission to function is called a transmitting unit (transmitting unit) or a transmitter (transmitter). In any case, as described above, the realization method is not particularly limited.

  For example, the structure evaluation system according to an embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method according to the present disclosure. FIG. 9 is a diagram illustrating an example of a hardware configuration of a computer 100 that functions as the structure evaluation system 10. The computer 100 may physically include a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, and the like.

  In the following description, the term “apparatus” can be read as a circuit, a device, a unit, or the like. The hardware configuration of the structure evaluation system 10 may be configured to include one or more devices illustrated in the drawing, or may be configured to exclude some devices.

  Each function of the structure evaluation system 10 is configured such that the processor 1001 performs an operation by reading predetermined software (program) on hardware such as the processor 1001 and the memory 1002, and controls communication by the communication device 1004, It is realized by controlling at least one of reading and writing of data in the memory 1002 and the storage 1003.

  The processor 1001 controls the entire computer by operating an operating system, for example. The processor 1001 may be configured by a central processing unit (CPU) including an interface with a peripheral device, a control device, an arithmetic device, a register, and the like.

  In addition, the processor 1001 reads a program (program code), a software module, data, and the like from at least one of the storage 1003 and the communication device 1004 to the memory 1002, and executes various processes according to these. As the program, a program that causes a computer to execute at least a part of the operation described in the above embodiment is used. For example, each functional element of the structure evaluation system 10 may be realized by a control program stored in the memory 1002 and operated by the processor 1001. Although it has been described that the various processes described above are executed by one processor 1001, the processes may be executed simultaneously or sequentially by two or more processors 1001. Processor 1001 may be implemented by one or more chips. Note that the program may be transmitted from a network via a telecommunication line.

  The memory 1002 is a computer-readable recording medium, and includes, for example, at least one of a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electrically Erasable Programmable ROM), and a RAM (Random Access Memory). May be done. The memory 1002 may be called a register, a cache, a main memory (main storage device), or the like. The memory 1002 can store a program (program code), a software module, and the like that can be executed to execute the wireless communication method according to an embodiment of the present disclosure.

  The storage 1003 is a computer-readable recording medium such as an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, and a magneto-optical disk (eg, a compact disk, a digital versatile disk, a Blu-ray). (Registered trademark) disk, a smart card, a flash memory (eg, card, stick, key drive), a floppy (registered trademark) disk, a magnetic strip, or the like. The storage 1003 may be called an auxiliary storage device. The above-described storage medium may be, for example, a database including at least one of the memory 1002 and the storage 1003, a server, or another appropriate medium.

  The communication device 1004 is hardware (transmission / reception device) for performing communication between computers via at least one of a wired network and a wireless network, and is also referred to as, for example, a network device, a network controller, a network card, a communication module, or the like. The communication device 1004 includes a high-frequency switch, a duplexer, a filter, a frequency synthesizer, and the like, for example, in order to realize at least one of frequency division duplex (FDD) and time division duplex (TDD). May be configured.

  The input device 1005 is an input device that receives an external input (for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, and the like). The output device 1006 is an output device that performs output to the outside (for example, a display, a speaker, an LED lamp, and the like). Note that the input device 1005 and the output device 1006 may have an integrated configuration (for example, a touch panel).

  Each device such as the processor 1001 and the memory 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using a different bus for each device.

  The computer 100 includes hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), and a field programmable gate array (FPGA). And some or all of the functional blocks may be realized by the hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

  As described above, a structure evaluation system according to an aspect of the present disclosure includes an acquisition unit that acquires image data of a structure, and a determination unit that determines a state of the structure based on the image data. The part calculates the respective displacements of the one or more measurement points of the structure and the reference point of the structure from the image data, and for each of the one or more measurement points, calculates the displacement of the one or more measurement points and the displacement of the reference point. The ratio is calculated as a relative displacement, and the state of the structure is determined based on the relative displacement of each of the one or more measurement points.

  A structure evaluation method according to an aspect of the present disclosure is a structure evaluation method executed by a computer system, wherein an obtaining step of obtaining image data of a structure, and determining a state of the structure based on the image data A sub-step of calculating respective displacements of one or more measurement points of the structure and a reference point of the structure from the image data, and determining the displacement of each of the one or more measurement points. The method includes the sub-step of calculating the ratio of the displacement of the measurement point to the displacement of the reference point as a relative displacement, and the sub-step of determining the state of the structure based on the relative displacement of each of the one or more measurement points.

  In such an aspect, the displacement of each measurement point of the structure is converted into a relative value using the displacement of the reference point, and the state of the structure is determined based on the relative value. According to this method, the state of the structure can be accurately determined without acquiring the load applied to the structure. When the relative displacement of each of the plurality of measurement points is used, the state of each location of the structure can be determined, and thus, for example, it is possible to determine where the structure has deteriorated.

  The relationship between the load f applied to the structure, the displacement x generated in the structure, and the rigidity k of the structure is represented by f = kx. Therefore, originally, it is necessary to obtain the load f and the displacement x in order to obtain the rigidity k. However, it is difficult to accurately estimate the load f as described above.

On the other hand, according to one aspect of the present disclosure, it is possible to grasp the relative value of the rigidity k by using a relative displacement that is a ratio between the displacement of the measurement point and the displacement of the reference point. If the load f applied to the structure during a certain period (generally, a short time) is constant, the relationship f = k _{ax a} holds at a certain measurement point, and the relationship f = k _b x _{b at} a reference point. Holds. Therefore, k _{ax a} = k _{b xb} holds, and therefore k _a / k _b = x _b / x _a . Since the relative value of rigidity k (in other words, the relation or difference in rigidity between the measurement point and the reference point) can be obtained from the relative displacement without considering the load f, even if the load f is unknown, The state can be determined.

It should be noted that if the difference between the displacement of the measurement point and the displacement of the reference point is set as the relative displacement instead of the ratio, the load f must be considered. If the load f is constant, a relationship of f = k _{ax a} holds at a certain measurement point, and a relationship of f = k _b x _b holds at a reference point. Since this from two equations _{1 / k b -1 / k a} = (x b -x a) / f is obtained, it is necessary to know the load f to obtain a relative value of the stiffness. Therefore, it is technically significant to determine the ratio between the displacement of the measurement point and the displacement of the reference point as a relative displacement.

  In the structure evaluation system according to another aspect, the image data includes first image data of the structure during the reference period and second image data of the structure during the inspection period, and the determination unit determines that the first image data Based on the second image data, a relative displacement distribution is generated for each of one or more measurement points as a first relative displacement distribution, and a relative displacement distribution is generated for each of the one or more measurement points based on the second image data. The state of the structure during the inspection period may be determined by generating the distribution and comparing the first relative displacement distribution with the second relative displacement distribution. By comparing the relative displacement distributions in the two periods, a change in the relative displacement with the passage of time can be grasped, so that the state of the structure during the inspection period can be accurately determined.

  In the structure evaluation system according to another aspect, the determination unit compares the first average value of the first relative displacement distribution with the second average value of the second relative displacement distribution, thereby determining a state of the structure during the inspection period. May be determined. By comparing the average values of the two relative displacement distributions, the state of the structure can be easily and accurately determined.

  In the structure evaluation system according to another aspect, the determination unit changes the first average value by a given amount and compares the changed first average value with the second average value. May be determined. By adjusting the first average value and comparing the two average values, a significant change in the structure in the two periods can be more reliably determined.

  In the structure evaluation system according to another aspect, the determination unit may compare the first average value and the second average value using Welch's t-test. By using this test method, even when the sample size differs between the reference period and the inspection period, it is possible to compare the average values of the two periods, and thus it is possible to accurately determine the state of the structure. is there.

  In the structure evaluation system according to another aspect, the image data includes the first image data of the structure at the reference time and the second image data of the structure at the time of the inspection, and the determination unit converts the first image data into the first image data. Based on the second image data, a relative displacement is generated as a first relative displacement for each of the one or more measurement points, and a relative displacement is generated as a second relative displacement for each of the one or more measurement points based on the second image data. The state of the structure at the time of inspection may be determined by comparing the first relative displacement with the second relative displacement. By comparing the relative displacements at the two points in time, a change in the relative displacement over time can be grasped, so that the state of the structure at the time of the inspection can be accurately determined.

  In the structure evaluation system according to another aspect, the determination unit may select a measurement point having the largest displacement among a plurality of measurement points of the structure as a reference point. It can be expected that the larger the displacement, the smaller the ratio of error. Therefore, by using the measurement point at which the maximum displacement is recorded as the reference point, it is possible to reduce the error of the relative displacement, and to accurately determine the state of the structure.

  In the structure evaluation system according to another aspect, the determination unit may calculate a temporary displacement by analyzing the image data, and calculate the displacement by applying a low-pass filter to the temporary displacement. According to this method, a static change of the measurement point is obtained by removing the vibration component, so that a more accurate displacement can be obtained.

  In the structure evaluation system according to another aspect, the structure may be a bridge, and the determination unit may set one or more measurement points and reference points to a bridge girder of the bridge. According to this method, it is possible to accurately determine the state of a bridge, particularly a bridge girder, without acquiring a load applied to the bridge (for example, the weight of an object passing through the bridge).

  While the present disclosure has been described in detail, it will be apparent to one skilled in the art that the present disclosure is not limited to the embodiments described in the present disclosure. The present disclosure can be implemented as modified and changed aspects without departing from the spirit and scope of the present disclosure defined by the description of the claims. Therefore, the description of the present disclosure is intended for illustrative purposes, and has no restrictive meaning to the present disclosure.

  The notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using another method. For example, the notification of information includes physical layer signaling (eg, DCI (Downlink Control Information), UCI (Uplink Control Information)), higher layer signaling (eg, RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling, Broadcast information (MIB (Master Information Block), SIB (System Information Block))), other signals, or a combination thereof may be used. Further, the RRC signaling may be called an RRC message, and may be, for example, an RRC connection setup message, an RRC connection reconfiguration message, or the like.

  Each aspect / embodiment described in the present disclosure is applicable to LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system). system), FRA (Future Radio Access), NR (new Radio), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark) )), Systems utilizing IEEE 802.16 (WiMAX®), IEEE 802.20, UWB (Ultra-WideBand), Bluetooth®, and other suitable systems and extensions based thereon. It may be applied to at least one of the next generation systems. Further, a plurality of systems may be combined (for example, a combination of at least one of LTE and LTE-A with 5G) and applied.

  The processing procedure, sequence, flowchart, and the like of each aspect / embodiment described in the present disclosure may be rearranged as long as there is no inconsistency. For example, for the methods described in this disclosure, elements of various steps are presented in an exemplary order, and are not limited to the specific order presented.

  The specific operation described as being performed by the base station in the present disclosure may be performed by its upper node in some cases. In a network consisting of one or more network nodes having a base station, various operations performed for communication with the terminal may be performed by the base station and other network nodes other than the base station (eg, MME or It is clear that this can be done by at least one of S-GW or the like (but not limited to these). In the above, the case where the number of other network nodes other than the base station is one is illustrated, but a combination of a plurality of other network nodes (for example, MME and S-GW) may be used.

  Information and the like can be output from an upper layer (or lower layer) to a lower layer (or upper layer). Input and output may be performed via a plurality of network nodes.

  The input and output information and the like may be stored in a specific place (for example, a memory) or may be managed using a management table. Information that is input and output can be overwritten, updated, or added. The output information or the like may be deleted. The input information or the like may be transmitted to another device.

  The determination may be made based on a value represented by 1 bit (0 or 1), a Boolean value (Boolean: true or false), or a comparison of numerical values (for example, a predetermined value). Value).

  Each aspect / embodiment described in the present disclosure may be used alone, may be used in combination, or may be switched and used with execution. In addition, the notification of the predetermined information (for example, the notification of “X”) is not limited to explicitly performed, and is performed implicitly (for example, not performing the notification of the predetermined information). Is also good.

  Software, regardless of whether it is called software, firmware, middleware, microcode, a hardware description language, or any other name, instructions, instruction sets, codes, code segments, program codes, programs, subprograms, software modules , Applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, and the like.

  In addition, software, instructions, information, and the like may be transmitted and received via a transmission medium. For example, if the software uses at least one of wired technology (coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), etc.) and wireless technology (infrared, microwave, etc.), the website, When transmitted from a server or other remote source, at least one of these wired and / or wireless technologies is included within the definition of a transmission medium.

  The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc., that can be referred to throughout the above description are not limited to voltages, currents, electromagnetic waves, magnetic or magnetic particles, optical or photons, or any of these. May be represented by a combination of

  Note that terms described in the present disclosure and terms necessary for understanding the present disclosure may be replaced with terms having the same or similar meaning. For example, at least one of the channel and the symbol may be a signal (signaling). Also, the signal may be a message. Further, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, or the like.

  The terms "system" and "network" as used in this disclosure are used interchangeably.

  Further, the information, parameters, and the like described in the present disclosure may be expressed using an absolute value, may be expressed using a relative value from a predetermined value, or may be expressed using another corresponding information. May be represented. For example, the radio resource may be indicated by an index.

  The names used for the parameters described above are not limiting in any way. Further, equations and the like using these parameters may differ from those explicitly disclosed in the present disclosure. Since the various channels (eg, PUCCH, PDCCH, etc.) and information elements can be identified by any suitable name, the various names assigned to these various channels and information elements may be limited in any way. is not.

  In the present disclosure, “base station (BS)”, “wireless base station”, “fixed station”, “NodeB”, “eNodeB (eNB)”, “gNodeB (gNB)”, “ “Access point”, “transmission point”, “reception point”, “transmission / reception point”, “cell”, “sector”, “cell group”, “ Terms such as "carrier" and "component carrier" may be used interchangeably. A base station may also be referred to as a macro cell, a small cell, a femto cell, a pico cell, or the like.

  A base station can accommodate one or more (eg, three) cells. If the base station accommodates multiple cells, the entire coverage area of the base station can be partitioned into multiple smaller areas, each smaller area being a base station subsystem (eg, a small indoor base station (RRH: The communication service can also be provided by a Remote Radio Head.The term “cell” or “sector” is a part or the whole of a coverage area of at least one of a base station and a base station subsystem that provide communication service in this coverage. Point to.

  In the present disclosure, terms such as “Mobile Station (MS)”, “user terminal”, “User Equipment (UE)”, “terminal” and the like may be used interchangeably. .

  A mobile station can be a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, by one of ordinary skill in the art. It may also be called a terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable term.

  At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a communication device, or the like. Note that at least one of the base station and the mobile station may be a device mounted on the mobile unit, the mobile unit itself, or the like. The moving object may be a vehicle (for example, a car, an airplane, or the like), may be an unmanned moving object (for example, a drone, an autonomous vehicle), or may be a robot (maned or unmanned). ). Note that at least one of the base station and the mobile station includes a device that does not necessarily move during a communication operation. For example, at least one of the base station and the mobile station may be an IoT (Internet of Things) device such as a sensor.

  Further, the base station in the present disclosure may be replaced with a user terminal. For example, communication between a base station and a user terminal is replaced with communication between a plurality of user terminals (for example, may be called D2D (Device-to-Device), V2X (Vehicle-to-Everything), etc.). Each aspect / embodiment of the present disclosure may be applied to the configuration. In this case, the user terminal may have the function of the base station. Further, words such as “up” and “down” may be read as words corresponding to communication between terminals (for example, “side”). For example, an uplink channel, a downlink channel, and the like may be replaced with a side channel.

  Similarly, a user terminal in the present disclosure may be replaced with a base station. In this case, the base station may have the function of the user terminal.

  The terms "determining" and "determining" as used in the present disclosure may encompass a wide variety of operations. `` Judgment '', `` decision '', for example, judgment (judging), calculation (calculating), calculation (computing), processing (processing), derivation (deriving), investigating (investigating), searching (looking up, search, inquiry) (E.g., searching in a table, database, or another data structure), ascertaining may be considered "determined", "determined", and the like. Also, “determining” and “deciding” include receiving (eg, receiving information), transmitting (eg, transmitting information), input (input), output (output), and access. (accessing) (for example, accessing data in a memory) may be regarded as “determined” or “determined”. In addition, `` judgment '' and `` decision '' means that resolving, selecting, selecting, establishing, establishing, comparing, etc. are regarded as `` judgment '' and `` decided ''. May be included. In other words, “judgment” and “decision” may include deeming any operation as “judgment” and “determined”. “Judgment (determination)” may be read as “assuming”, “expecting”, “considering”, or the like.

  The terms "connected," "coupled," or any variation thereof, mean any direct or indirect connection or coupling between two or more elements that It may include the presence of one or more intermediate elements between the two elements "connected" or "coupled." The coupling or connection between the elements may be physical, logical, or a combination thereof. For example, “connection” may be read as “access”. As used in this disclosure, two elements may be implemented using at least one of one or more wires, cables, and printed electrical connections, and as some non-limiting and non-exhaustive examples, in the radio frequency domain. , Can be considered "connected" or "coupled" to each other using electromagnetic energy having wavelengths in the microwave and optical (both visible and invisible) regions, and the like.

  Reference to “based on” as used in the present disclosure does not mean “based solely on” unless otherwise indicated. In other words, the phrase "based on" means both "based only on" and "based at least on."

  Any reference to elements using designations such as "first", "second", etc., as used in the present disclosure, does not generally limit the quantity or order of those elements. These designations may be used in the present disclosure as a convenient way to distinguish between two or more elements. Thus, references to first and second elements do not mean that only two elements can be employed, or that the first element must precede the second element in some way.

  Where the terms “include”, “including” and variations thereof are used in the present disclosure, these terms are as inclusive as the term “comprising” Is intended. Further, the term "or" as used in the present disclosure is not intended to be an exclusive or.

  In the present disclosure, where articles are added by translation, for example, a, an and the in English, the present disclosure may include that the nouns following these articles are plural.

  In the present disclosure, the term “A and B are different” may mean “A and B are different from each other”. The term may mean that “A and B are different from C”. Terms such as "separate", "coupled" and the like may be interpreted similarly to "different".

  DESCRIPTION OF SYMBOLS 10 ... Structure evaluation system, 11 ... Acquisition part, 12 ... Judgment part, 13 ... Output part, 20 ... Camera, 21 ... Image database, 22 ... Displacement database, 80 ... Bridge (structure), 80a ... Measurement point, 81 -85: measurement point, 90: steel tower (structure), 90a: measurement point.

Claims (10)

An acquisition unit for acquiring image data of the structure,
A determining unit that determines a state of the structure based on the image data,
The determination unit is
Calculating respective displacements of one or more measurement points of the structure and a reference point of the structure from the image data,
For each of the one or more measurement points, a ratio between the displacement of the measurement point and the displacement of the reference point is calculated as a relative displacement,
Determining the state of the structure based on the relative displacement of each of the one or more measurement points,
Structure evaluation system. The image data includes first image data of the structure during a reference period, and second image data of the structure during an inspection period,
The determination unit is
Based on the first image data, a distribution of the relative displacement is generated as a first relative displacement distribution for each of the one or more measurement points,
Based on the second image data, a distribution of the relative displacement for each of the one or more measurement points is generated as a second relative displacement distribution,
By comparing the first relative displacement distribution and the second relative displacement distribution, a state of the structure during the inspection period is determined.
The structure evaluation system according to claim 1. The determination unit determines a state of the structure during the inspection period by comparing a first average value of the first relative displacement distribution with a second average value of the second relative displacement distribution.
The structure evaluation system according to claim 2. The determination unit changes the first average value by a given amount, compares the changed first average value with the second average value, and thereby changes the state of the structure during the inspection period. judge,
The structure evaluation system according to claim 3. The determination unit compares the first average value and the second average value using Welch's t-test,
The structure evaluation system according to claim 3. The image data includes first image data of the structure at a reference time, and second image data of the structure at an inspection time,
The determination unit is
Based on the first image data, the relative displacement is generated as a first relative displacement for each of the one or more measurement points,
Generating the relative displacement as a second relative displacement for each of the one or more measurement points based on the second image data;
By comparing the first relative displacement and the second relative displacement, determine the state of the structure at the time of the inspection,
The structure evaluation system according to claim 1. The determination unit selects the measurement point having the largest displacement as the reference point among a plurality of measurement points of the structure,
The structure evaluation system according to claim 1. The determination unit calculates a tentative displacement by analyzing the image data, and calculates the displacement by applying a low-pass filter to the tentative displacement,
The structure evaluation system according to claim 1. The structure is a bridge;
The determination unit sets the one or more measurement points and the reference point on a bridge girder of the bridge;
The structure evaluation system according to any one of claims 1 to 8. A structure evaluation method executed by a computer system,
An acquisition step of acquiring image data of the structure;
Determining a state of the structure based on the image data,
The determining step includes:
Calculating a displacement of each of one or more measurement points of the structure and a reference point of the structure from the image data;
For each of the one or more measurement points, a sub-step of calculating the ratio of the displacement of the measurement point and the displacement of the reference point as a relative displacement,
Determining a state of the structure based on the relative displacement of each of the one or more measurement points,
Structure evaluation method.

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