JP6511892B2 - State determination apparatus for a structure, state determination system, and state determination method - Google Patents

Description

  The present invention relates to a technique for remotely determining a state such as a defect occurring in a structure.

  In concrete structures such as tunnels and bridges, it is known that defects such as cracks, separations and internal cavities generated on the surface of the structure affect the soundness of the structure. Therefore, in order to accurately determine the soundness of the structure, it is necessary to accurately detect these defects.

  The detection of defects such as cracks, peelings and internal cavities in structures has been carried out by visual inspection and hammering inspection by inspectors, and it is necessary for the inspector to approach the structures for inspection. As a result, there are problems such as an increase in the cost of work by preparing an environment where work in the air is possible, and a loss of economic opportunities due to traffic regulation for setting the work environment. A method of remote inspection is desired.

  There is a method by image measurement as a method of determining the state of a structure remotely. For example, there has been proposed a technique for binarizing an image obtained by imaging a structure with an imaging device with a predetermined threshold and detecting an image portion corresponding to a crack from the binarized image (Patented Literature 1). Moreover, the technique which detects the crack which has arisen in the structure from the stress state of a structure is proposed (patent document 2, patent document 3). Also, a system that automatically analyzes a captured image to determine a defect of a measurement object using both an infrared imaging device or a visible light imaging device and a laser imaging device (Patent Document 4), and excellent portability. The method (patent document 5) which produces a defect map from the image imaged with the imaging means is proposed. Further, Non-Patent Document 1 discloses a method of enhancing the detection accuracy of a crack by detecting the movement of a crack region by a moving image of a surface of a structure.

Japanese Patent Application Publication No. 2003-035528 JP 2008-232998 A JP, 2006-343160, A Unexamined-Japanese-Patent No. 2004-347585 Japanese Patent Laid-Open No. 2002-236100 JP 2012-132786 A

Z. Wang, et al. “Crack-opening displacement estimation method based on sequence of motion vector field images for civil infrastructure discrimination inspection”, Image media processing symposium (PCSJ / IMPS 2014), I-1-17, 2014.

  However, in the case of imaging the lower surface of a structure such as a bridge, for example, in the above-mentioned technology, displacement of the surface to be imaged moves in the normal direction of the surface by bending the structure due to load (out-of-plane) The displacement) is added to the in-plane displacement (referred to as in-plane displacement) of the surface having information on the defect of the structure. For this reason, there existed a problem that the precision at the time of detecting the defect of a structure falls.

  Patent Document 6 proposes, in a method of measuring distortion generated on the surface of a measurement object, a method of correcting the amount of out-of-plane displacement from the displacement of a captured image. In Patent Document 6, the amount of out-of-plane displacement is read from side images before and after deformation of a structure. For this purpose, two imaging devices are provided: a first imaging device for imaging the surface of the structure and a second imaging device for imaging the side surface.

  However, in this method, in order to capture the side surface, another imaging device is required in addition to the imaging device that captures the surface, and there is a problem of cost increase. Furthermore, in the case of a bridge, for example, there is a need to fix an imaging device or secure a footing of a worker for measurement of the side of the bridge, so the workability is poor and the measurement accuracy is lowered. There is.

  The present invention has been made in view of the above problems, and its object is to separate out-of-plane displacement due to movement in the normal direction of the surface of the structure from work-related displacement from the displacement of the image of the structure surface under load. Then, in-plane displacement of the surface of the structure can be extracted. Accordingly, it is possible to accurately perform remote detection in a non-contact manner with distinctions between defects such as cracking and peeling of a structure and an internal cavity.

  The state determination device according to the present invention is measured from the imaging direction of the time-series image, and a displacement calculation unit that calculates a two-dimensional spatial distribution of the displacement of the time-series image from the time-series image before and after load application on the surface of the structure. A correction amount calculation unit that calculates a correction amount based on the movement amount in the normal direction of the surface of the structure by the load application; and subtracting the correction amount from a two-dimensional spatial distribution of displacement of the time-series image; Based on a comparison of a displacement correction unit for extracting a two-dimensional space distribution of the surface displacement of the structure, a two-dimensional space distribution of the displacement of the surface of the structure, and a spatial distribution of the displacement provided in advance, And an abnormality determination unit that specifies a defect.

  The state determination system according to the present invention comprises: a displacement calculation unit that calculates a two-dimensional spatial distribution of displacement of the time-series image from time-series images before and after load application on the surface of the structure; A correction amount calculation unit for calculating a correction amount based on a movement amount of a direction, and subtracting the correction amount from a two-dimensional spatial distribution of displacement of the time-series image to extract a two-dimensional spatial distribution of displacement of the structure surface A state determination device including: a displacement correction unit; and an abnormality determination unit that specifies a defect of the structure based on comparison between a two-dimensional space distribution of displacement of the surface of the structure and a spatial distribution of displacement prepared beforehand. An imaging unit configured to capture the time-series image and provide the state determination device; and a distance measurement unit configured to measure the movement amount from the imaging direction of the time-series image and provide the state determination device.

  The state determination method according to the present invention calculates the two-dimensional spatial distribution of displacement of the time-series image from the time-series image before and after load application on the surface of the structure and measures the load application measured from the imaging direction of the time-series image Calculating the correction amount based on the movement amount in the normal direction of the surface of the structure due to a two-dimensional space distribution of the surface of the structure by subtracting the correction amount from the two-dimensional spatial distribution of the displacement of the time-series image A distribution is extracted, and a defect of the structure is identified based on comparison of a two-dimensional space distribution of displacement of the structure surface with a spatial distribution of displacement prepared in advance.

  According to the present invention, out-of-plane displacement due to movement in the normal direction of the structure surface can be separated with good workability from displacement due to load of the image of the structure surface, and in-plane displacement of the structure surface can be extracted become. As a result, it is possible to perform detection with high accuracy and remoteness without contact, which distinguishes defects such as cracking and peeling of the structure and internal cavities.

It is a block diagram showing composition of a state judging device of an embodiment of the present invention. It is a block diagram which shows the concrete structure of the state determination apparatus of embodiment of this invention. It is a block diagram showing composition of a state judging system of an embodiment of the present invention. It is a figure for demonstrating the relationship between the state of a structure (when it is healthy), and the displacement of a surface. It is a figure for demonstrating the relationship between the state of a structure (in the case of a crack), and the displacement of a surface. It is a figure for demonstrating the relationship between the state (in the case of peeling) of a structure, and the displacement of a surface. It is a figure for demonstrating the relationship between the state of a structure (in the case of an internal cavity), and the displacement of a surface. It is a figure which shows the result of having calculated the displacement of the surface of the X direction of the structure (in the case of a crack) before and behind loading by a displacement calculation part. It is a figure which shows the result of having calculated the displacement of the surface of the Y direction of the structure (in the case of a crack) before and behind loading by a displacement calculation part. It is a block diagram which shows the structure of the distance measurement part of embodiment of this invention. It is a figure which shows the mode of a movement of the position of the structure part surface of the measuring object of the distance measurement part of embodiment of this invention. It is a figure for demonstrating the calculation method of the correction amount in the correction amount calculation part of embodiment of this invention. It is a figure which shows the result of having calculated the in-plane displacement of the surface of the X direction of the structure (in the case of a crack) before and behind loading by a displacement correction part. It is a figure which shows the result of having calculated the in-plane displacement of the surface of the Y direction of the structure (in the case of a crack) before and behind loading by a displacement correction part. It is a figure for demonstrating the calculation method of correction amount in case there is inclination in the correction amount calculation part of embodiment of this invention. It is the figure which showed distribution of the stress field around a crack. It is the figure which showed distribution of the stress field around a crack. It is a figure which shows the example of the two-dimensional distribution (X direction) of the displacement amount around a crack (when a crack is shallow). It is a figure which shows the example of the two-dimensional distribution (Y direction) of the displacement amount around a crack (when a crack is shallow). It is a figure which shows the example of the two-dimensional distribution (X direction) of the displacement amount around a crack (when a crack is deep). It is a figure which shows the example of the two-dimensional distribution (Y direction) of the displacement amount around a crack (when a crack is deep). It is a figure explaining pattern matching with displacement distribution (pattern of the direction of displacement of X) by an unusual judging part. It is a figure explaining pattern matching with displacement distribution (pattern of the Y direction of displacement) by an unusual judging part. It is a figure explaining pattern matching with displacement distribution (pattern of a differential vector field of displacement) by an unusual judging part. It is a perspective view which shows the two-dimensional distribution of the stress of the surface seen from the imaging direction in case an internal cavity exists. It is a top view which shows the two-dimensional distribution of the stress of the surface seen from the imaging direction in case an internal cavity exists. It is a figure which shows the contour line (X component) of the displacement of the surface seen from the imaging direction in case an internal cavity exists. It is a figure which shows the contour line (Y component) of the displacement of the surface seen from the imaging direction in case an internal cavity exists. It is a figure which shows the stress field of the surface seen from the imaging direction in case an internal cavity exists. It is a figure explaining a response when an impulse stimulus is given to a structure in case an internal cavity exists (a position ABC which shows a response is shown). It is a figure explaining a response when an impulse stimulus is given to a structure in case an internal cavity exists (a response in position ABC is shown). It is a figure which shows the contour line (X component) of the displacement of the surface seen from the imaging direction in case peeling exists. It is a figure which shows the contour line (Y component) of the displacement of the surface seen from the imaging direction in case peeling exists. It is a figure which shows the stress field of the surface seen from the imaging direction in case peeling exists. It is a figure explaining the time response of displacement at the time of giving impulse stimulus to a structure in case exfoliation exists. It is a flowchart which shows the state determination method in the state determination apparatus of embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the embodiments described below are technically preferable limitations for carrying out the present invention, but the scope of the invention is not limited to the following.

  FIG. 1 is a block diagram showing the configuration of a state determination device according to an embodiment of the present invention. The state determination apparatus 100 of the present embodiment calculates a two-dimensional spatial distribution of displacement of the time-series image from the time-series image before and after the load application on the surface of the structure, and the imaging direction of the time-series image A correction amount calculation unit 102 for calculating a correction amount based on the movement amount in the normal direction of the surface of the structure by the load application, and the correction amount from the two-dimensional spatial distribution of displacement of the time series image Based on the comparison of the displacement correction unit 103 for subtracting the two-dimensional spatial distribution of the displacement of the surface of the structure and subtracting the two-dimensional spatial distribution of the displacement of the surface of the structure and the spatial distribution of the displacement provided in advance And an abnormality determination unit 104 that specifies a defect of the structure.

  FIG. 2 is a block diagram showing a specific configuration of the state determination device according to the embodiment of the present invention. The state determination device 1 includes a displacement calculation unit 2, a correction amount calculation unit 3, a displacement correction unit 4, a differential displacement calculation unit 5, an abnormality determination unit 6, and an abnormality map generation unit 9. The abnormality determination unit 6 includes a two-dimensional space distribution information analysis unit 7 and a time change information analysis unit 8.

  FIG. 3 is a block diagram showing the configuration of the state determination system according to the embodiment of this invention. The state determination system 10 includes a state determination device 1, an imaging unit 11, a distance measurement unit 12, and a tilt measurement unit 13. The state determination device 1 is a device shown in FIG. The imaging unit 11 is a camera for imaging. In FIG. 3, the structure 15 which is an object to be measured has a beam-like structure supported at two points. In the structure 15, various defects 14 may exist.

  The imaging unit 11 captures the surface of the structure 15 before and after applying a load to the structure 15 as a time-series image of the XY plane. Furthermore, the imaging unit 11 inputs the captured time-series image to the displacement calculation unit 2 of the state determination device 1.

  The distance measurement unit 12 detects a distance between the imaging unit 11 and the surface of the structure 15 imaged by the imaging unit 11 (referred to as an imaging distance). Furthermore, the distance measuring unit 12 detects a change in which the imaging distance changes as the surface of the structure 15 moves in the direction of the normal to the surface as the structure 15 bends by applying a load. That is, the distance measuring unit 12 can measure the imaging distance and the change from the same direction as the imaging direction of the video unit 11. The distance measuring unit 12 inputs the imaging distance and the change amount to the correction amount calculating unit 3 as distance information.

  Note that although the normal is referred to when the surface is a curved surface, in the case where the surface has a plurality of small curved surfaces to form a large curved surface as a whole, the normal to the large curved surface is referred to here. . In addition, when the surface is a plane, it is referred to as a perpendicular line, but in the following description, it will be described as being unified with a normal line for simplification.

  The inclination measuring unit 13 detects the inclination angle of the normal to the surface of the structure 15 with respect to the optical axis at the center of the imaging direction of the imaging unit 11, that is, the inclination angle of the structure 15. Enter as The tilt measurement unit 13 can obtain tilt information from the same direction as the imaging direction of the video unit 11.

  The displacement calculation unit 2 calculates the displacement for each (X, Y) coordinate on the XY plane of the time-series image. That is, the displacement in the frame image at the first time after the load application is calculated based on the frame image before the load application captured by the imaging unit 11. Next, the displacement with respect to the image before loading is calculated for each time-series image in the same manner as the displacement of the frame image at the next time after the application of the load and the displacement of the frame image at the next time. The displacement calculation unit 2 can calculate the displacement using image correlation operation. In addition, the displacement calculating unit 2 can also represent the calculated displacement as a displacement distribution chart in which a two-dimensional space distribution of the XY plane is made.

  The correction amount calculation unit 3 uses the distance information from the distance measurement unit 12 and the inclination information from the inclination measurement unit 13 and is included in the displacement calculated by the displacement calculation unit 2, and the structure 15 is A displacement (referred to as an out-of-plane displacement) due to movement of the surface of the structure 15 in the normal direction of the surface is calculated by bending or the like.

  The displacement correction unit 4 subtracts the out-of-plane displacement calculated by the correction amount calculation unit 3 from the displacement or displacement distribution map calculated by the displacement calculation unit 2 to generate the displacement generated in the surface of the structure 15 ( Extract in-plane displacement). The displacement correction unit 4 inputs the extracted in-plane displacement to the differential displacement calculation unit 5 and the abnormality determination unit 6.

  The differential displacement calculation unit 5 performs spatial differentiation on the displacement or displacement distribution map, and calculates a differential displacement distribution map in which the differential displacement or the calculated differential displacement is a two-dimensional differential space distribution on the X-Y plane. The calculation results of the displacement correction unit 4 and the differential displacement calculation unit 5 are input to the abnormality determination unit 6.

  The abnormality determination unit 6 determines the state of the structure 15 based on the input calculation result. That is, from the analysis results of the two-dimensional space distribution information analysis unit 7 and the time change information analysis unit 8, the abnormality determination unit 6 determines the location and the type of the abnormality (defect 14) of the structure 15. Further, the abnormality determination unit 6 inputs the determined abnormality location and type of the structure 15 to the abnormality map creation unit 9. The anomaly map creation unit 9 maps the spatial distribution of the anomaly state of the structure 15 on the XY plane, records it as an anomaly map, and outputs it.

  The state determination device 1 can be an information device such as a PC (Personal Computer) or a server. Each unit constituting the state determination apparatus 1 is operated by operating a program by a CPU using a central processing unit (CPU) which is a computing resource of an information device and a memory or a hard disk drive (HDD) which is a storage resource. It can be realized.

  4A to 4D are diagrams for explaining the relationship between various abnormal states of the structure 15 and in-plane displacement of the surface. FIG. 4A is a side view of the beam-like structure 15 supported at two points. As shown to FIG. 4A, the imaging part 11 in FIG. 3 is arrange | positioned on the conditions which image the lower surface of the structure 15 from an imaging direction (Z direction). At this time, if the structure 15 is sound, as shown in FIG. 4A, a compressive stress is applied to the upper surface of the structure 15 and a tensile stress is applied to the lower surface to the vertical load from the upper surface of the structure 15. . The structure 15 may not be a beam-like structure supported particularly by two points as long as the same stress is exerted.

  Here, when the structure 15 is an elastic body, the stress is proportional to the strain. The Young's modulus, which is a proportional constant, depends on the material of the structure. Since the strain proportional to the stress is a displacement per unit length, the strain can be calculated by spatially differentiating the result calculated by the displacement correcting unit 4 by the differential displacement calculating unit 5. That is, the stress field can be obtained from the result of the differential displacement calculation unit 5.

  As shown in FIG. 4B, when there is a crack, the cracked portion has a large displacement due to the load. On the other hand, in the vicinity of the cracked portion, there is no transmission of stress due to the cracked portion, so the tensile stress on the lower surface of the structure 15 becomes smaller than that in the sound state shown in FIG. 4A.

  Further, as shown in FIG. 4C, in the case where peeling is present, the appearance as seen from the lower surface of the structure 15 is similar to that in the case of the crack. However, in the case of exfoliation, there is no stress transfer between the exfoliated part and its upper part. Therefore, the displacement due to the load only moves a fixed amount in parallel in the fixed direction at the separation portion, and no distortion which is the spatial differential value occurs. Therefore, it becomes possible to distinguish a crack and exfoliation by using information on strain obtained by spatially differentiating displacement by load.

  Also, as shown in FIG. 4D, when the internal cavity is present, the stress transmission on the internal cavity is hindered, so the stress on the lower surface of the structure 15 is reduced. Therefore, since distortions calculated from images are also small, it is possible to find an internal cavity that can not be seen directly from the outside of the structure 15.

  Hereinafter, with reference to FIGS. 5A and 5B, a method of removing the out-of-plane displacement and extracting the in-plane displacement will be described by taking an example where there is a crack along the Y direction as shown in FIG. 4B. FIG. 5A is a view showing the result of calculation of displacement of the surface in the X direction due to load by the displacement calculation unit 2 in the case where there is a crack along the Y direction of the structure 15 of FIG. 3. FIG. 5B is a view showing the result of calculating the displacement of the surface in the Y direction by the displacement calculating unit 2 in the same manner as FIG. 5A. Here, the imaging distance is 5 m, the structure 15 is 20 m long, 0.5 m thick, and 10 m wide concrete (Young's modulus 40 GPa), and a double-supported beam with conditions equivalent to the load of 10 t is used. ing.

  In FIG. 5A showing displacement in the X direction, displacement of ± 170 μm occurs in the range of imaging range ± 200 mm. In FIG. 5B showing displacement in the Y direction, displacement of ± 160 μm occurs linearly in the range of imaging range ± 200 mm. The displacement in the X direction is a displacement in which out-of-plane displacement is superimposed on in-plane displacement. On the other hand, displacement in the Y direction is displacement only in out-of-plane displacement.

  FIG. 6A shows the configuration of the distance measurement unit 12. The distance measuring unit 12 measures the distance between the imaging unit 11 and the surface of the structure 15. The distance measuring unit 12 includes a signal generator 121, a transmitter 122, a receiver 123, a time comparator 124, and a distance calculator 125.

  The signal generator 121 generates a pulse signal. The transmitter 122 transmits an ultrasonic wave corresponding to the pulse signal generated by the signal generator 121. The ultrasonic waves transmitted from the transmitter 122 are reflected by the surface of the structure 15 and received by the receiver 123. The time comparator 124 calculates the time from transmission to reception from the time when the transmitter 122 transmitted the ultrasonic wave and the time when the receiver 123 received the ultrasonic wave. This is the time for the ultrasonic waves to reciprocate the distance z between the distance measurement unit 12 and the surface of the structure 15 (corresponding to the distance between the imaging unit 11 and the surface of the structure 15).

  Furthermore, the time comparator 124 calculates the time before and after the load is applied to the structure 15, whereby the surface of the structure 15 moves in the normal direction of the surface by bending the structure 15 due to the load or the like. A time difference Δt corresponding to a change in distance Δz caused thereby is obtained. The distance calculator 125 calculates the distance z from the time from the transmission to reception of the ultrasonic wave, and calculates the change Δz of the distance z from the time difference Δt, and inputs it to the correction amount calculation unit 3 of the state determination device 1 as distance information. .

  FIG. 6B is a view showing the movement of the surface position of the distance measurement unit 12 and the structure unit 15 to be measured. The distance between the distance measuring unit 12 and the surface of the structure 15 is output at each time. For example, at time t1, the time from transmission to reception is 29.412 msec. If the speed of sound is 340 m / sec. It is found that the distance between the imaging unit 11 and the surface of the structure 15 is 5 m. Also, at time t2, the time from transmission to reception is 29.388 msec. If the speed of sound is 340 m / sec. To find that the distance is 4.96 m. Here, if time t1 is before application of load and time t2 is after time of load application, a variation Δz due to deflection of the structure 15 is calculated to be 4 mm. Preferably, the time t1 and the time t2 are matched with the timing at which the imaging unit 11 captures a time-series image before and after the load. This can enhance the accuracy of the correction.

  Also, for example, the signal generator 121 sets the pulse width of the pulse signal to 12.5 μsec. The time comparator 124 sets 25 nsec. Of 1/500 of the pulse width of the pulse signal. A distance resolution of 8.5 μm can be obtained by enabling time comparison to (band 2 MHz with pulse ON / OFF). The distance measuring unit 12 may use not only ultrasonic waves but also laser beams or microwaves as long as the same resolution can be obtained, and the principle of triangular measurement may be used as a method other than using a time difference. It may be a method to use.

  The correction amount calculation unit 3 calculates the out-of-plane displacement δi based on the change amount Δz of the distance before and after the load obtained from the distance measurement unit 12. FIG. 7 is a diagram for explaining a method of calculating the correction amount in the correction amount calculation unit 3. In FIG. 7, it is assumed that the change Δz in the distance corresponds to the deflection of the structure before and after the load, and the change Δz is described as the deflection δ. The amount of change Δz is not limited to the amount of deflection, and includes, for example, the case where the position of the surface to be imaged moves in the normal direction of the surface as the entire structure 15 sinks under load. May be

As shown in FIG. 7, when deflection (deflection amount δ) occurs in the structure 15 due to a load, the imaging surface of the imaging unit 11 has an in-plane displacement Δx that is a two-dimensional space distribution of displacement of the structure surface. Apart from the corresponding Δxi, an out-of-plane displacement δi occurs due to the amount of deflection δ. The out-of-plane displacement δi and the in-plane displacement Δxi are expressed by Equation 1 and Equation 2, respectively, assuming that the imaging distance is L, the focal distance of the lens is f, and the distance from the imaging center of the structure surface is x. .
δi = x · f · {1 / (L−δ) −1 / L} (Expression 1)
Δxi = Δx · f / (L−δ) (Expression 2)
Here, when the deflection amount δ of the structure 15 before and after the load is 4 mm, the imaging distance L is 5 m, and the lens focal distance f is 50 mm, imaging is performed at a distance x of 200 mm from the imaging center on the surface of the structure 15 From the equation 1, the out-of-plane displacement δi of the surface is 1.6 μm. On the other hand, when there is an in-plane displacement Δx of 160 μm on the surface of the structure 15, the in-plane displacement Δxi of the imaging surface is 1.6 μm according to Expression 2.

  As described above, the out-of-plane displacement δi equivalent to the in-plane displacement Δxi is superimposed on the displacement of the time-series image calculated by the displacement calculation unit 2 and the displacement distribution map as a two-dimensional space distribution of the XY plane. May be The displacement correction unit 4 extracts the in-plane displacement Δxi by subtracting the out-of-plane displacement δi obtained by the correction amount calculation unit 3 from the displacement obtained by the displacement calculation unit 2 as a correction amount.

  The in-plane displacements extracted by subtracting the out-of-plane displacement obtained by the correction amount calculating unit 3 from the displacements calculated by the displacement calculating unit 2 in FIGS. 5A and 5B are respectively shown in FIGS. 8A and 8B. FIG. 8A is a view showing the result of calculation of the in-plane displacement of the surface in the X direction due to a load by the displacement correction unit 4 of a structure having a crack in the Y direction. FIG. 8B is a view showing the result of calculation of the in-plane displacement of the surface in the Y direction due to the load of the similar structure by the displacement correction unit 4. In the cracked portion, it can be seen that a sudden 20 μm in-plane displacement occurs discontinuously in the X direction. On the other hand, it can be seen that no in-plane displacement occurs in the Y direction.

  5A and 5B and FIGS. 8A and 8B, if it is known in advance that in-plane displacement occurs only in the X direction and not in the Y direction, then subtract FIGS. 5A to 5B. Thus, the in-plane displacement of FIG. 8A can be obtained.

  FIG. 9 is a view for explaining the out-of-plane displacement in the case where the structure 15 is inclined in the method of calculating the correction amount in the correction amount calculation unit 3 according to the embodiment of this invention. In the correction amount calculation unit 3, the inclination angle θ (that is, the inclination angle of the structure 15) of the surface normal of the structure 15 with respect to the optical axis at the center of the imaging direction of the imaging unit 11 from the inclination measurement unit 13 is inclined It is input as information.

As shown in FIG. 9, when the normal to the surface of the structure 15 is rotated by θ with the Y axis as an axis, the coordinate with the optical axis of the imaging unit 11 as the z axis and the normal to the surface of the structure is z The relationship with the coordinates of 'is expressed by Equations 3, 4, and 5.
x ′ = x · cos θ + z · sin θ (Equation 3)
y '= y (Equation 4)
z ′ = − x · sin θ + z · cos θ (Equation 5)
Furthermore, the XY coordinates of the imaging surface rotated by θ are mapped by Equations 6 and 7.
X = x ′ · f / (L−z ′) (Equation 6)
Y = y ′ · f / (L−z ′) (Equation 7)
Therefore, the out-of-plane displacement in the X direction δxi in the Y direction due to the displacement from the coordinate P1 (x1, y1, z1) to the coordinate P2 (x2, y2, z2) when the structure 15 is bent by the application of a load. The outer displacements δ yi are respectively expressed by Equations 8 and 9 (Y component is not shown in FIG. 9).
δxi = x2i−x1i = x2 · f / (L−z2) −x1 · f / (L−z1) (Equation 8)
δyi = y2i−y1i = y2 · f / (L−z2) −y1 · f / (L−z1) (Equation 9)
In FIG. 9, the case where the normal of the surface of the structure 15 is rotated by θ with respect to the optical axis at the center of the imaging direction of the imaging unit 11 with the Y axis as an axis is dealt with. In the case of using as an axis, the correction can be performed in the same way.

  The inclination measurement unit 13 can measure inclination by detecting the direction of gravity using a capacitive acceleration sensor based on MEMS (Micro Electro Mechanical Systems) technology. Also, as long as the inclination can be measured, various types of acceleration sensors or various types of gyro sensors may be used.

  The in-plane displacement of the surface of the structure, which is the output of the displacement correction unit 4, is replaced by the distortion of the surface of the structure in the differential displacement calculation unit 5. Since the strain on the surface of the structure multiplied by the Young's modulus results in a stress, the stress field on the surface of the structure is determined from this. The displacement information obtained by the displacement correction unit 4 and the distortion information obtained by the differential displacement calculation unit 5 are input to the abnormality determination unit 6.

  The abnormality determination unit 6 is a two-dimensional space distribution information analysis unit in order to specify the type and location of the defect with respect to the displacement information obtained by the displacement correction unit 4 and the distortion information obtained by the differential displacement calculation unit 5. 7 and the time change information analysis unit 8 are provided in advance with a threshold for determining a defect and a characteristic displacement or distortion pattern corresponding to the type of the defect. Then, as shown in FIGS. 4A to 4D, the two-dimensional space distribution information analysis unit 7 and the time change information analysis unit 8 compare the displacement information or the distortion information with the threshold, or pattern matching with the pattern. Health condition or defects such as cracking, peeling and internal cavity.

  FIG. 8A shows an example of in-plane displacement of the surface in the X direction of the structure due to load when there is a crack along the Y direction. In the cracked portion, it can be seen that a discontinuous 20 μm rapid in-plane displacement occurs. Such a sudden displacement does not occur in a sound state without defects. Therefore, it is possible to detect a crack by confirming the displacement exceeding this by providing a threshold value in the magnitude | size of a discontinuous displacement beforehand.

  FIG. 10A and FIG. 10B are diagrams showing distributions of stress fields around the cracked area calculated by the differential displacement calculation unit 5 when there is a crack along the Y direction. As shown in FIG. 10A, since the stress direction is bent due to the crack, even when tensile stress acts on both ends of the structure in the X direction in FIG. 10A, the stress direction in the vicinity of the crack is Y direction as shown in FIG. The component of is generated. Therefore, the crack can also be detected by detecting the presence or absence of the component in the Y direction. In addition, since the stress field around such a crack is known as a stress intensity factor in an elastic body exhibiting a linear response, it is possible to use the information.

  11A to 11D show examples of two-dimensional displacement distributions of displacement around a crack. 11A and 11B respectively show displacement contour lines in the horizontal direction (X direction) in FIG. 4B and in the direction (Y direction) perpendicular to the paper surface in FIG. 4B. As shown in FIG. 11A, in the X direction, the density of displacement amount contour lines is sparser around the crack than in the region where there is no crack. This corresponds to the portion of the outer gradual displacement of the rapid displacement at the cracked portion shown in FIG. 8A. The displacement at this part is slower than the displacement without cracks.

  Moreover, as shown to FIG. 11B, the component of the Y direction of a displacement arises around a crack part regarding Y direction. This corresponds to the Y direction component of the stress field (strain) shown in FIG. 10B.

  11C and 11D show the case where the crack is deeper than the case of FIGS. 11A and 11B, respectively. In this case, the density of displacement contour lines becomes sparser around the crack in each of the X direction and the Y direction. It is also possible to know the depth of the crack from this sparse and dense information.

  The above determination of the crack is performed by the two-dimensional space distribution information analysis unit 7 in the abnormality determination unit 6 in FIG.

  When there is a crack, as shown in FIG. 8A, in the cracked portion, the displacement amount rapidly increases in response to the increase of the crack opening. Therefore, it is possible to estimate that there is a crack in the place where the displacement amount exceeding the threshold is detected by providing in advance the threshold value of the displacement amount per unit length in the X direction or the Y direction.

  In addition, strain in the X direction rapidly increases at the cracked portion. From this, it is possible to presume that there is a crack in the place where the strain exceeding the threshold is detected by providing the threshold in advance in the value of the strain in the X direction.

  Also, as shown in FIG. 10A and FIG. 10B, if there is a crack, strain in the Y direction occurs. Therefore, by providing a threshold value in advance in the value of strain in the Y direction, it can be estimated that there is a crack in a place where the strain exceeding the threshold is detected.

  Each of the above threshold values can be set by simulation using dimensions and materials similar to those of the structure, and experiments using a reduced model. In addition, the actual structure can be set from measured and accumulated data over a long period of time.

  The above determination can also be performed by pattern matching processing as described below, without using the above-described numerical comparison.

  12A to 12C are diagrams for explaining pattern matching processing of displacement distribution by the two-dimensional space distribution information analysis unit 7. According to the displacement correction unit 4 and the differential displacement calculation unit 5, as shown in FIGS. 11A to 11D, the displacement amount can be represented as a displacement distribution map on the XY plane. As shown in FIG. 12A, the two-dimensional space distribution information analysis unit 7 rotates and scales the X direction pattern of the displacement around the crack stored in advance, and the displacement distribution map obtained by the displacement correction unit 4 and The pattern matching of can determine the direction and depth of the crack. Here, the X direction pattern of displacement around a crack stored in advance can be created in advance by simulation or the like for each depth and width of the crack.

  In addition, as shown in FIG. 12B, the two-dimensional space distribution information analysis unit 7 rotates and scales the Y-direction pattern of the displacement around the crack stored in advance, and the displacement distribution obtained by the displacement correction unit 4 The direction and depth of the crack are determined by pattern matching with the figure. Here, the Y direction pattern of the displacement around the crack stored in advance can be created in advance by simulation or the like for each depth and width of the crack.

  Further, as shown in FIG. 12C, the two-dimensional space distribution information analysis unit 5 is obtained by the differential displacement calculation unit 5 by rotating and scaling the pattern of the differential vector field of the displacement around the crack stored in advance. The direction and depth of the crack are determined by pattern matching with a differential vector field (corresponding to a stress field). Here, the pattern of the differential vector field of the displacement around the crack stored in advance can be created in advance by simulation or the like for each depth and width of the crack.

  A correlation operation is used for the pattern matching. Various other statistical arithmetic methods may be used for pattern matching.

  As mentioned above, although the case where the structure 15 has a crack has been described, the case where it has an internal cavity and the case where it has peeling will be described below.

  FIGS. 13A and 13B show a two-dimensional distribution of stress in the plane viewed from the imaging direction when there is an internal cavity as shown in FIG. 4D. FIG. 13A is a perspective view, and FIG. 13B is a plan view. As shown in FIG. 13B, the load exerts a stress in the X direction in the figure, but the stress field is bent in the hollow portion, so that there is a component in the Y direction in the figure in the stress.

  14A to 14C are diagrams showing contours and stress fields of displacement of the surface viewed from the imaging direction in the presence of an internal cavity, where contours of the X component of the displacement are shown in FIG. 14A, contours of the Y component of the displacement Is shown in FIG. 14B and the stress field is shown in FIG. 14C.

  In the hollow portion, since the amount of strain decreases as described in the description of FIG. 4D, the density of contour lines of the X component of the displacement illustrated in FIG. 14A decreases. Further, the contour line of the Y component of the displacement shown in FIG. 14B is a closed curve. Furthermore, the stress field, which is a derivative of displacement, shown in FIG. 14C will bend at the cavity. The effect of the stress field on the surface is more pronounced as the cavity is closer to the surface, so the depth from the surface of the cavity can also be estimated from the bending of the stress field.

  Here, the pattern of the displacement in the X direction of the displacement around the cavity, the pattern of the displacement in the Y direction of the displacement around the cavity, and the differential vector field (corresponding to a stress field) stored in advance by the two-dimensional space distribution information analysis unit 7 14A in FIG. 12A, FIG. 14B in FIG. 12B, and FIG. 14C in FIG. 12C, as in the case of determining cracks, it is possible to determine the state of the position and depth of the internal cavity. Although correlation calculation is used for the pattern matching, other statistical calculation methods may be used.

  Also in the case of having an internal cavity, it is also possible to pre-set a threshold value for these displacement amount and strain from the characteristic of the displacement amount in Y direction and the distortion in Y direction and to have an internal cavity when exceeding this. it can.

  FIGS. 15A and 15B are diagrams for explaining the response when a load is given to a structure having an internal cavity for a short time (referred to as impulse stimulation). Impulse stimulation can be applied, for example, at a position where a load is applied. The time response of displacement at each point on the surfaces of A, B, and C shown in FIG. 15A to this impulse stimulus is shown in FIG. 15B. At point A where there is no internal cavity, stress transfer is fast and the amplitude of displacement is also large. On the other hand, at point C, since stress is not transmitted in the internal cavity, stress is transmitted from the periphery of the cavity, so that stress transmission is slow and the amplitude of displacement is small. Further, the stress transfer time and the amplitude at a point B which is an intermediate point between the point A and the point C become a value intermediate between the point A and the point C. Therefore, the frequency distribution of the displacement distribution in the plane of the structure viewed from the imaging direction is analyzed by the time change information analysis unit 8 in the abnormality determination unit 6, and the amplitude and phase near the resonance frequency indicate the region of the internal cavity. Can be identified. Alternatively, the internal cavity may be determined from the deviation of the resonance frequency.

  Even when the load is applied for a long time, the displacement variation corresponding to FIG. 15B is confirmed in the initial stage of applying the load. However, in this case, the convergence value of the displacement is not zero but a value balanced with the load. Therefore, even when a load is applied for a long time, the time change information analysis unit 8 can specify the region of the internal cavity.

  The processing of the time response of displacement described above is performed in the time change information analysis unit 8 by frequency analysis using fast Fourier transform. Further, various frequency analysis methods such as wavelet transform may be used for frequency analysis.

  16A to 16C are diagrams showing contours and stress fields of displacement of a surface viewed from the imaging direction in the presence of exfoliation, where contours of the X component of displacement are shown in FIG. 16A and contours of the Y component of displacement. The stress fields are shown in FIG. 16C, respectively.

  As shown in FIG. 4C, when exfoliation is present, an appearance similar to a crack is observed in the appearance viewed from the lower surface of the beam-like structure. However, since there is no stress transfer between the exfoliated portion and the upper portion thereof, the displacement before and after the load is only parallel displacement of a fixed amount in a fixed direction in the exfoliated portion, and distortion which is the spatial differential value does not occur.

  FIG. 16A shows contours of the X component of displacement. There is no distortion and there is no contour line in the peeled portion because it moves in a fixed direction. Using this feature, the abnormality determination unit 6 determines that peeling is present. In addition, since the portion at point A in the figure is a tear due to peeling and stress is hard to be transmitted, the contour line becomes sparser than the point B which is a healthy portion. The abnormality determination unit 6 may determine the peeled portion and the sound portion using this property.

  FIG. 16B shows contours of the Y component of displacement. A displacement in the Y direction occurs on the outer side of the outer periphery of the peeled portion. Using this feature, the abnormality determination unit 6 can determine that peeling is present. Further, the stress field which is the differential of the displacement shown in FIG. Using this feature, the abnormality determination unit 6 can determine that peeling is present.

  Here, a pattern of displacement in the X direction of displacement around separation, a pattern of displacement in the Y direction of displacement around a cavity, and a differential vector field (corresponding to a stress field) stored in advance by the two-dimensional space distribution information analysis unit 7 As in the case of determining the depth of cracks, the position of peeling can be determined by applying FIG. 16A to FIG. 12A, FIG. 16B to FIG. 12B, and FIG. Although correlation calculation is used for the pattern matching, other statistical calculation methods may be used.

  FIG. 17 is a diagram showing a time response when a structure having exfoliation is subjected to impulse stimulation. In the time response, the direction of displacement is reversed in the peeled portion and the healthy portion, that is, the waveform has a phase difference of 180 °. In addition, since the peeled portion is light, the amplitude is large. By performing frequency analysis on the displacement distribution in the plane of the surface of the structure viewed from the imaging direction by the time change information analysis unit 8, it is possible to specify the peeled portion from the amplitude and the phase. In addition, since the exfoliated portion floats from the entire structure, it may include a frequency component different from that of the entire structure. Therefore, the exfoliated portion may be determined from the shift of the resonance frequency.

  In the above processing, frequency analysis in the time change information analysis unit 8 uses fast Fourier transform. For frequency analysis, various frequency analysis methods such as wavelet transform may be used.

  FIG. 18 is a flowchart showing a state determination method of the state determination device 1 of FIG.

  In step S1, the displacement calculation unit 2 of the state determination device 1 determines the displacement amounts before and after applying the load in the time-series image of the surface of the structure 15 before and after applying the load captured by the imaging unit 11. The frame image before applying the load, which is the reference to be calculated, is captured, and the frame image after applying the load is captured in time series.

  Furthermore, the displacement calculation unit 2 calculates displacement amounts in the X and Y directions of the image after application of the load with respect to the image before application of the load serving as a reference. Furthermore, a two-dimensional distribution of the calculated displacement amounts may be a displacement distribution chart (contours of displacement amounts) displayed on an X-Y plane. Further, the displacement calculating unit 2 inputs the calculated displacement amount or displacement distribution map to the displacement correcting unit 4.

  In step S2, the correction amount calculation unit 3 receives the distance information between the imaging unit 11 and the surface of the structure 15 from the distance measurement unit 12 and the inclination measurement unit 13, the optical axis of the imaging unit 11, and the structure, respectively. The angle information of the angle with the normal of the surface of 15 is acquired.

  In step S3, the correction amount calculation unit 3 calculates the out-of-plane displacement from the distance information and the angle information.

  In step S4, the displacement correction unit 4 subtracts the out-of-plane displacement obtained by the correction amount calculation unit 3 from the displacement amount obtained by the displacement calculation unit 2 to extract an in-plane displacement. That is, the displacement correction unit 4 calculates the in-plane displacement in the XY direction of the surface of the structure 15 after the load application with respect to the reference load application. Furthermore, a two-dimensional distribution of the calculated in-plane displacement may be a displacement distribution chart (contours of displacement amounts) displayed on an XY plane. The displacement correction unit 4 inputs the calculated result to the differential displacement calculation unit 5 and the abnormality determination unit 6.

  In step S5, the differential displacement calculation unit 5 spatially differentiates the in-plane displacement or displacement distribution map input from the displacement correction unit 4 to calculate a differential displacement amount (stress value) or a differential displacement distribution map (stress field). Do. The differential displacement calculation unit 5 inputs the calculated result to the abnormality determination unit 6.

  The following steps S6, S7, and S8 are steps in which the two-dimensional space distribution information analysis unit 7 of the abnormality determination unit 6 determines a crack, peeling, or an internal cavity that is a defect of the structure. As a determination method, the method by pattern matching mentioned above and the method by threshold value are mentioned and explained.

  In step S6, the two-dimensional space distribution information analysis unit 7 of the abnormality determination unit 6 determines the state of a crack, peeling, or an internal cavity from the input displacement amount or displacement distribution chart in the X direction.

  First, the determination method by pattern matching will be described. The two-dimensional space distribution information analysis unit 7 includes, as a database, displacement distribution patterns created in advance corresponding to the width and depth of cracks, internal cavities, and peeling as shown in FIGS. 12A, 14A, and 16A. ing. The two-dimensional space distribution information analysis unit 7 rotates, scales, and matches these displacement distribution patterns with respect to the displacement distribution chart in the X direction input from the displacement correction unit 4 to obtain defects in the XY plane. Determine the location and type of

  Next, the determination method using the threshold value of the displacement amount will be described. The two-dimensional space distribution information analysis unit 7 determines, for example, the continuity of the displacement amount based on the input displacement amount in the X direction. That is, as shown in FIG. 8A, the presence or absence of continuity is determined based on the presence or absence of a sharp change that is equal to or greater than the threshold value of the displacement amount. The two-dimensional space distribution information analysis unit 7 determines that there is a possibility that a crack or peeling may exist in the place if there is a sharp change without continuity in any place on the XY plane, The continuous flag DisC (x, y, t) is set to 1 and displacement amount data of a portion having a sharp change is recorded as numerical information. Here, t is the time on the time-series image of the frame image captured in step S1.

  The abnormality determination unit 6 inputs information on the defect determined by pattern matching, or the discontinuity flag DisC (x, y, t) determined based on the threshold of the displacement amount and numerical information to the abnormality map creation unit 9.

  In step S7, the two-dimensional space distribution information analysis unit 7 of the abnormality determination unit 6 determines the state of the crack, peeling, and the internal cavity from the input displacement amount or displacement distribution chart in the Y direction.

  First, the determination method by pattern matching will be described. The two-dimensional space distribution information analysis unit 7 has, as a database, displacement distribution patterns created in advance corresponding to the widths and depths of cracks, internal cavities and peeling as shown in FIGS. 12B, 14B and 16B. ing. The two-dimensional space distribution information analysis unit 7 performs pattern matching on the displacement distribution chart in the Y direction input from the displacement correction unit 4 by rotating and scaling these displacement distribution patterns, in the XY plane. Determine the location and type of defects.

  Next, the determination method using the threshold value of the displacement amount will be described. If there are cracks, peeling, and defects in the internal cavity, displacement occurs in the Y direction as well. Therefore, when the two-dimensional space distribution information analysis unit 7 detects a displacement amount larger than a predetermined threshold value, the two-dimensional space distribution information analysis unit 7 determines that there is a defect in the location and sets the orthogonal flag ortho (x, y, t) to 1 While being set, displacement amount data of a point where a displacement amount larger than the threshold is detected is recorded as numerical information.

  The abnormality determination unit 6 inputs information on the defect determined by pattern matching, or the orthogonal flag ortho (x, y, t) determined based on the displacement amount or numerical information to the abnormality map creation unit 9.

  In step S8, the two-dimensional space distribution information analysis unit 7 of the abnormality determination unit 6 determines the state of a crack, peeling, or an internal cavity from the input differential displacement amount (stress value) or differential displacement distribution map (stress field) Do.

  First, the determination method by pattern matching will be described. The two-dimensional space distribution information analysis unit 7 has, as a database, displacement distribution patterns created in advance corresponding to the widths and depths of cracks, internal cavities and peeling as shown in FIGS. 12C, 14C and 16C. ing. The two-dimensional space distribution information analysis unit 7 performs pattern matching on the differential displacement distribution map input from the differential displacement calculation unit 5 by rotating and scaling these displacement distribution patterns, and defects in the XY plane Determine the location and type of

  Next, the determination method using the threshold value of the differential displacement amount will be described. For example, the strain in the X direction rapidly increases because the differential value of displacement diverges at the cracked portion. From this, it is possible to determine that there is a crack in the portion where the strain exceeding the threshold is detected by providing the threshold in advance for the value of the strain. The two-dimensional space distribution information analysis unit 7 determines that there is a crack at the location based on the input differential displacement amount, sets 1 to the differential value flag Diff (x, y, t), and The differential displacement data of is recorded as numerical information.

  The abnormality determination unit 6 inputs information on the defect determined by pattern matching, or the differential value flag Diff (x, y, t) determined based on the differential displacement amount and numerical information to the abnormality map creation unit 9.

  In step S9, the displacement calculating unit 2 determines whether the processing of each frame image of the time-series images is completed. That is, when the number of frames of the time-series image is n, it is determined whether the process of the n-th frame is finished. If the process does not reach n (NO), the process from step S1 is repeated. This is repeated until n sheets are finished. Note that n is not limited to the total number of frames, and can be set to an arbitrary number. If the process has ended n sheets (YES), the process proceeds to step S10.

  In step S10, the time change information analysis unit 8 of the abnormality determination unit 6 determines the time response of the displacement as shown in FIG. 15B and FIG. 17 from the time-series displacement amount or displacement distribution map corresponding to n frame images. Analyze That is, from the n displacement distribution maps I (x, y, n), the time frequency distribution (time frequency is f) is assumed to be amplitude A (x, y, f) and phase P (x, y, f) It is calculated. The time change information analysis unit 8 determines that there is an internal cavity at the position where the phase shift occurs, when the time frequency distribution has the feature that the phase differs depending on the place as shown in FIG. 15B. When the polarity of displacement is reversed as shown in FIG. 17, it is determined that there is peeling between the points. The time change information analysis unit 8 inputs the above calculation result of the time frequency distribution and the determination result of the defect to the abnormality map generation unit 9.

  In step 11, the anomaly map creation unit 9 creates the anomaly map (x, y) based on the information input in the above steps. The results sent from the two-dimensional space distribution information analysis unit 7 and the time change information analysis unit 8 are data groups related to the point (x, y) on the XY coordinates. In these data, the state of the structure is determined by the two-dimensional space distribution information analysis unit 7 and the time change information analysis unit 8 in the abnormality determination unit 6.

  These determinations are made for displacement or displacement distribution in the X direction, displacement or displacement distribution in the Y direction, differential displacement or differential displacement, and time responses of displacement and differential displacement. Therefore, even if the abnormality map creation unit 9 generates missing data, for example, the determination in the Y direction displacement amount is not performed, the determination in the X direction displacement amount and the differential displacement amount is attached. By this, it is possible to determine the state of the relevant part in the XY coordinates. Then, based on this determination, the anomaly map (x, y) can be created.

  Further, when determining the defect state, if the determinations of the displacement in the X direction, the displacement in the Y direction, and the differential displacement are different from each other, they may be determined by majority decision. Also, it may be determined as the item having the largest difference from the threshold as the determination criterion.

  Further, the abnormality map creation unit 9 can express the degree of the defect based on the above-mentioned various numerical value information. For example, the width and depth of a crack, the size of separation, the size of an internal cavity, and the depth from a surface can be expressed.

  Further, the abnormality map creation unit 9 creates the anomaly map (x, y) for the determination of the defect state of the structure performed by the two-dimensional space distribution information analysis unit 7 and the time change information analysis unit 8 in the anomaly determination unit 6 It can also be done at the same time. That is, analysis data may be obtained from the two-dimensional space distribution information analysis unit 7 and the time change information analysis unit 8, and the abnormality map generation unit 9 may make a determination of the defect state based on the analysis data.

  Further, the result output of the abnormality map creation unit 9 may be information in a form that can be directly visualized by a person on a display device, or may be information in a form for a machine to read.

  In the present embodiment, for example, the lens focal length of the imaging unit 11 is 50 mm, the pixel pitch is 5 μm, and a pixel resolution of 500 μm can be obtained at an imaging distance of 5 m. The image pickup element of the image pickup unit 11 can use monochrome monochrome pixels having 2000 horizontal pixels and 2000 vertical pixels, and can capture an area of 1 m × 1 m at an imaging distance of 5 m. The frame rate of the imaging device can be 60 Hz.

  Further, in the image correlation in the displacement calculation unit 2, sub-pixel displacement estimation by quadratic curve interpolation can be used so that displacement estimation can be performed up to 1/100 pixels, and a displacement resolution of 5 μm can be obtained. The following various methods can be used for subpixel displacement estimation in image correlation. In addition, a smoothing filter can be used to reduce noise at the time of differentiation in displacement differentiation.

  Interpolation by a quadratic surface, an equiangular straight line, or the like may be used for subpixel displacement estimation. For image correlation operation, various methods such as sum of absolute difference (SAD), sum of squared difference (SSD), normalized cross correlation (NCC), and zero-mean normalized cross correlation (ZNCC) are used. May be Also, any combination of these methods with the sub-pixel displacement estimation method described above may be used.

  The lens focal length of the imaging unit 11, the pixel pitch of the imaging device, the number of pixels, and the frame rate may be changed as appropriate according to the measurement object.

  In the present embodiment, for example, the beam structure may correspond to a bridge, and the load may correspond to a traveling vehicle. In the above description, the load is applied to the beam-like structure. However, even when the load moves on the bridge like a traveling vehicle, the crack, the internal cavity, and the peeling can be similarly detected. In addition, if it exhibits the same behavior as the above description in terms of material mechanics, a load method different from loading a load on another material, a structure having a size or a shape, or a structure, for example, suspending a load The present invention can be applied to load methods such as lowering.

  In addition, as long as time-series signals of spatial two-dimensional distribution of surface displacement of a structure can be measured, the present invention is not limited to time-series images, but arrayed laser Doppler sensors, arrayed strain gauges, and arrayed vibration sensors An array of acceleration sensors or the like may be used. A spatial two-dimensional time-series signal obtained from these arrayed sensors may be treated as image information.

  In the present embodiment, distance information and tilt information for calculating out-of-plane displacement due to movement in the normal direction of the surface of the structure are taken from the same direction as the imaging direction for imaging an image of the structure surface at the timing of imaging. It can be acquired together. The amount of movement of the surface of the structure in the normal direction can in principle be obtained by measuring the amount of deflection due to load from the side direction of the structure. However, for example, in the case where the structure is a bridge or the like, measurement from the side of the bridge is extremely difficult in working, and therefore the measurement accuracy is also lowered. The present embodiment can also solve this problem in operation, so that the displacement of the image on the surface of the structure can be corrected with high accuracy.

  As described above, according to the present embodiment, the out-of-plane displacement due to the movement in the normal direction of the structure surface is separated with good workability from the displacement due to the load of the image of the structure surface. Internal displacement can be extracted. As a result, it is possible to perform detection with high accuracy and remoteness without contact, which distinguishes defects such as cracking and peeling of the structure and internal cavities.

  The present invention is not limited to the above embodiment, and various modifications are possible within the scope of the invention described in the claims, and they are also included in the scope of the present invention.

  Moreover, although a part or all of the above-mentioned embodiment may be described as the following additional notes, it is not limited to the following.

Appendix (Supplementary Note 1)
A displacement calculation unit that calculates a two-dimensional spatial distribution of displacement of the time-series image from the time-series image before and after load application on the surface of the structure;
A correction amount calculation unit that calculates a correction amount based on the movement amount in the normal direction of the surface of the structure by the application of the load, which is measured from the imaging direction of the time-series image;
A displacement correction unit that extracts a two-dimensional spatial distribution of displacement of the structure surface by subtracting the correction amount from a two-dimensional spatial distribution of displacement of the time-series image;
A state determination device, comprising: an abnormality determination unit that specifies a defect of the structure based on a comparison between a two-dimensional space distribution of displacement of the surface of the structure and a space distribution of displacement provided in advance.
(Supplementary Note 2)
The state determination system according to appendix 1, wherein the correction amount calculation unit calculates the correction amount based on the movement amount obtained by correcting the tilt angle of the structure.
(Supplementary Note 3)
The state determination device according to appendix 2, wherein an amount of movement in a direction normal to the surface of the structure or an inclination angle of the structure is measured at the same timing as imaging of the time-series image.
(Supplementary Note 4)
And a differential displacement calculation unit that calculates a two-dimensional differential spatial distribution from the two-dimensional spatial distribution of the displacement of the structure surface,
The anomaly judgment unit according to any one of Appendices 1 to 3, wherein a defect of the structure is specified based on comparison between the two-dimensional differential space distribution and a differential space distribution of differential displacements prepared in advance. State determination device of.
(Supplementary Note 5)
The state determination device according to any one of Appendices 1 to 4, wherein the abnormality determination unit identifies a defect of the structure based on a temporal change of a two-dimensional space distribution of displacement of the surface of the structure.
(Supplementary Note 6)
The state determination apparatus according to Additional Note 4 or 5, wherein the abnormality determination unit specifies a defect of the structure based on a temporal change of the two-dimensional differential space distribution.
(Appendix 7)
The state according to any one of Appendices 1 to 6, wherein the abnormality determination unit identifies a defect of the structure based on comparison between a displacement amount of displacement of the surface of the structure and a threshold provided in advance. Judgment device.
(Supplementary Note 8)
The abnormality determination unit according to any one of Appendices 4 to 7, wherein a defect of the structure is identified based on comparison between a differential displacement amount of displacement of the surface of the structure and a threshold value provided in advance. State determination device.
(Appendix 9)
The state determination apparatus according to any one of appendices 1 to 8, further comprising: an abnormality map creation unit configured to create an abnormality map indicating the location and type of the defect based on the determination result of the abnormality determination unit.
(Supplementary Note 10)
The condition determination device according to any one of Appendices 1 to 9, wherein the type of the defect includes a crack, a peeling, and an internal cavity.
(Supplementary Note 11)
The state determination device according to claim 10, wherein the pre-provided spatial distribution of displacement and the pre-provided differential spatial distribution of differential displacement are based on the information on the crack, the peeling, and the internal cavity.
(Supplementary Note 12)
The two-dimensional space distribution according to any one of Appendices 1 to 11, wherein the distribution of the displacement in the X direction in the XY plane of the displacement, the distribution of the displacement in the Y direction in the XY plane of the displacement, State determination device.
(Supplementary Note 13)
A displacement calculation unit that calculates a two-dimensional spatial distribution of displacement of the time-series image from time-series images before and after load application on the surface of the structure, and correction amount based on the movement amount in the normal direction of the structure surface by the load application. A correction amount calculation unit that calculates the displacement amount, a displacement correction unit that extracts the two-dimensional spatial distribution of the displacement of the surface of the structure by subtracting the correction amount from the two-dimensional spatial distribution of displacement of the time-series image; A state determination device including: an abnormality determination unit that specifies a defect of the structure based on a comparison between a two-dimensional space distribution of surface displacement and a space distribution of displacement provided in advance;
An imaging unit that captures the time-series image and provides the state determination device;
A state determination system, comprising: a distance measurement unit that measures the amount of movement from the imaging direction of the time-series images and provides the state determination device.
(Supplementary Note 14)
It has a tilt measurement unit that measures the tilt angle of the structure and provides the state determination device,
The state determination system according to claim 13, wherein the correction amount calculation unit calculates the correction amount based on the movement amount obtained by correcting the tilt angle.
(Supplementary Note 15)
The distance measurement unit or the tilt measurement unit measures the amount of movement in the normal direction of the surface of the structure or the tilt angle of the structure at the same timing as the imaging of the time-series image. State determination system described.
(Supplementary Note 16)
And a differential displacement calculation unit that calculates a two-dimensional differential spatial distribution from the two-dimensional spatial distribution of the displacement of the structure surface,
The abnormality determination unit identifies a defect of the structure based on comparison between the two-dimensional differential space distribution and a differential space distribution of differential displacement provided in advance.
The state determination system according to any one of appendices 13 to 15.
(Supplementary Note 17)
The state determination system according to any one of appendices 13 to 16, wherein the abnormality determination unit identifies a defect of the structure based on a temporal change of a two-dimensional space distribution of displacement of the structure surface.
(Appendix 18)
The state determination system according to claim 16, wherein the abnormality determination unit specifies a defect of the structure based on a temporal change of the two-dimensional differential space distribution.
(Appendix 19)
The state according to any one of Appendices 13 to 18, wherein the abnormality determination unit identifies a defect of the structure based on comparison between a displacement amount of displacement of the surface of the structure and a threshold value provided in advance. Judgment system.
(Supplementary Note 20)
The abnormality determination unit according to any one of appendices 16 to 19, wherein a defect of the structure is identified based on comparison between a differential displacement amount of displacement of the surface of the structure and a threshold value provided in advance. Condition judgment system.
(Supplementary Note 21)
The state determination system according to any one of appendices 13 to 20, further comprising: an abnormality map creation unit configured to create an abnormality map indicating the location and type of the defect based on the determination result of the abnormality determination unit.
(Supplementary Note 22)
The condition determination system according to any one of Appendices 13 to 21, wherein the type of the defect includes a crack, an abrasion, and an internal cavity.
(Supplementary Note 23)
24. The state determination system according to appendix 22, wherein the pre-provided spatial distribution of displacement and the differential spatial distribution of pre-provided differential displacement are based on the information of the crack, the exfoliation, and the internal cavity.
(Supplementary Note 24)
20. The two-dimensional space distribution according to any one of Appendices 13 to 23, including a distribution of displacement in the X direction in the XY plane of the displacement, and a distribution of displacement in the Y direction in the XY plane of the displacement. Condition judgment system.
(Appendix 25)
The two-dimensional spatial distribution of displacement of the time-series image is calculated from the time-series image before and after the load application on the surface of the structure,
Calculating a correction amount based on the movement amount in the normal direction of the surface of the structure by the application of the load, which is measured from the imaging direction of the time-series image;
The two-dimensional spatial distribution of displacement of the structure surface is extracted by subtracting the correction amount from the two-dimensional spatial distribution of displacement of the time-series image;
A state determination method of identifying a defect of the structure based on comparison between a two-dimensional space distribution of displacement of the surface of the structure and a spatial distribution of displacement prepared in advance.
(Appendix 26)
24. The state determination method according to appendix 25, wherein the correction amount is calculated based on the movement amount obtained by correcting the tilt angle of the structure.
(Appendix 27)
27. The state determination method according to appendix 26, wherein an amount of movement in a direction normal to the surface of the structure or an inclination angle of the structure is measured at the same timing as imaging of the time-series image.
(Appendix 28)
Calculating a two-dimensional differential space distribution of the two-dimensional space distribution from the two-dimensional space distribution;
The state determination method according to any one of Appendices 25 to 27, wherein a defect of the structure is identified based on a comparison between the two-dimensional differential spatial distribution and a differential spatial distribution of differential displacement provided in advance.
(Supplementary Note 29)
The state determination method according to any one of Appendices 25 to 28, wherein a defect of the structure is identified based on a temporal change of the two-dimensional space distribution.
(Supplementary note 30)
24. The state determination method according to appendix 28 or 29, wherein a defect of the structure is identified based on a temporal change of the two-dimensional differential spatial distribution.
(Supplementary Note 31)
The state determination method according to any one of Appendices 25 to 30, wherein a defect of the structure is identified based on a comparison between a displacement amount of the displacement of the structure surface and a previously prepared threshold value.
(Supplementary Note 32)
The condition determination method according to any one of Appendices 28 to 30, wherein a defect of the structure is identified based on a comparison between a differential displacement amount of the displacement of the structure surface and a previously prepared threshold value.
(Appendix 33)
The state determination method according to any one of appendices 25 to 32, wherein an abnormality map indicating the location and type of the defect is created based on the determination result.
(Appendix 34)
The condition determination method according to any one of Appendices 25 to 33, wherein the type of the defect includes a crack, an abrasion, and an internal cavity.
(Appendix 35)
29. The state determination method according to appendix 34, wherein the pre-provided spatial distribution of displacement and the differential spatial distribution of pre-provided differential displacement are based on the information on the crack, the exfoliation, and the internal cavity.
(Supplementary note 36)
The two-dimensional space distribution according to any one of Appendices 25 to 35, including a distribution of displacement in the X direction in the XY plane of the displacement, and a distribution of displacement in the Y direction in the XY plane of the displacement. State determination method.

1, 100 state determination device 2 displacement calculation unit 3 correction amount calculation unit 4 displacement correction unit 5 differential displacement calculation unit 6 abnormality determination unit 7 two-dimensional space distribution information analysis unit 8 time change information analysis unit 9 abnormality map creation unit 10 state determination System 11 imaging unit 12 distance measurement unit 13 inclination measurement unit 14 defect 15 structure 121 signal generator 122 transmitter 123 receiver 124 time comparator 125 distance calculator

Claims (10)

A displacement calculation unit that calculates a two-dimensional spatial distribution of displacement of the time-series image from the time-series image before and after load application on the surface of the structure;
A correction amount calculation unit that calculates a correction amount based on the movement amount in the normal direction of the surface of the structure by the application of the load, which is measured from the imaging direction of the time-series image;
A displacement correction unit that extracts a two-dimensional spatial distribution of displacement of the structure surface by subtracting the correction amount from a two-dimensional spatial distribution of displacement of the time-series image;
A state determination device, comprising: an abnormality determination unit that specifies a defect of the structure based on a comparison between a two-dimensional space distribution of displacement of the surface of the structure and a space distribution of displacement provided in advance. The state determination system according to claim 1, wherein the correction amount calculation unit calculates the correction amount based on the movement amount obtained by correcting the tilt angle of the structure. The state determination device according to claim 2, wherein an amount of movement in a direction normal to the surface of the structure or an inclination angle of the structure is measured at the same timing as imaging of the time-series image. And a differential displacement calculation unit that calculates a two-dimensional differential spatial distribution from the two-dimensional spatial distribution of the displacement of the structure surface,
The said abnormality determination part specifies the defect of the said structure based on comparison with the said two-dimensional differential space distribution, and the differential space distribution of the differential displacement previously provided, The claim in any one of Claim 1 to 3 State determination apparatus as described. The state determination apparatus according to any one of claims 1 to 4, wherein the abnormality determination unit identifies a defect of the structure based on a temporal change of a two-dimensional space distribution of displacement of the surface of the structure. The abnormality determination unit
Identifying defects in the structure based on temporal changes in the two-dimensional differential spatial distribution;
4. Symbol placement state determining apparatus.
A displacement calculation unit that calculates a two-dimensional spatial distribution of displacement of the time-series image from time-series images before and after load application on the surface of the structure, and correction amount based on the movement amount in the normal direction of the structure surface by the load application. A correction amount calculation unit that calculates the displacement amount, a displacement correction unit that extracts the two-dimensional spatial distribution of the displacement of the surface of the structure by subtracting the correction amount from the two-dimensional spatial distribution of displacement of the time-series image; A state determination device including: an abnormality determination unit that specifies a defect of the structure based on a comparison between a two-dimensional space distribution of surface displacement and a space distribution of displacement provided in advance;
An imaging unit that captures the time-series image and provides the state determination device;
A state determination system, comprising: a distance measurement unit that measures the amount of movement from the imaging direction of the time-series images and provides the state determination device. It has a tilt measurement unit that measures the tilt angle of the structure and provides the state determination device,
The state determination system according to claim 7, wherein the correction amount calculation unit calculates the correction amount based on the movement amount obtained by correcting the tilt angle. The distance measuring unit or the tilt measuring unit measures the amount of movement in the normal direction of the surface of the structure or the tilt angle of the structure at the same timing as the imaging of the time-series image. The state determination system described in 8. The two-dimensional spatial distribution of displacement of the time-series image is calculated from the time-series image before and after the load application on the surface of the structure,
Calculating a correction amount based on the movement amount in the normal direction of the surface of the structure by the application of the load, which is measured from the imaging direction of the time-series image;
The two-dimensional spatial distribution of displacement of the structure surface is extracted by subtracting the correction amount from the two-dimensional spatial distribution of displacement of the time-series image;
A state determination method of identifying a defect of the structure based on comparison between a two-dimensional space distribution of displacement of the surface of the structure and a spatial distribution of displacement prepared in advance.

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