JP5834532B2 - Mode analysis method and mode analysis system - Google Patents

Description

  The present invention relates to a mode analysis method and a mode analysis system, and specifically relates to a technique for performing mode analysis with good accuracy simply and at low cost.

  Various structures may be deformed by various external forces. When a structure is deteriorated or damaged, such deformation tends to increase, and it is important to observe the deformation in order to grasp the soundness of the structure. As a conventional method, there is a method of assembling a scaffold that reaches the observation point of the structure, installing a dial gauge with a measuring element in contact with the corresponding observation point, and observing the display value of this dial gauge. The temporary structure to be installed was large and measurement was not easy. As another method, a technique has been proposed in which a vibration sensor or an accelerometer is attached to a structure, and the displacement is observed by integrating the measured values. In addition, there is a method in which an image of an observation location is captured in advance, and a deviation between this image and the captured image is obtained as a displacement amount of the observation location.

No. 1-33696 JP-A-5-339909

  Here, in the case of a structure with a length in a certain direction, analyzing the behavior of the structure with respect to external force and trying to grasp the state of the structure, not only the displacement amount and frequency at each point It is important to confirm the deformation mode and vibration mode of the entire structure. There is also a method for estimating the vibration mode by performing a computer simulation based on the assumed external force and the strength characteristics of the structure, but this is only a simulation and does not confirm the substance.

  Conventionally, in order to specify such a vibration mode, etc., the above-described method for obtaining the displacement by integrating the acceleration value measured by the acceleration sensor has been used. In that case, a measuring device such as a sensor is installed on the structure. It is necessary to measure. However, the measurement itself is difficult because there are cases where it is not possible to secure a sufficient installation location for the measurement device in the structure, or there is a need to build a large temporary scaffolding around the structure for the arrangement of equipment and personnel. And there is a problem that the labor and cost for measurement increase.

  Accordingly, an object of the present invention is to provide a technique for performing mode analysis with good accuracy simply and at low cost.

The mode analysis method of the present invention that solves the above problems includes a first step of photographing a plurality of observation points, which are a plurality of predetermined portions exposed on the surface, of parts constituting the structure with a digital video camera group, From the video about each observation point obtained by shooting, a still image for each predetermined time is extracted starting from a predetermined time when the digital video cameras are synchronized, and the still images corresponding to the plurality of observation points An observation point specifying step for specifying the above pixel, a second step for specifying a displacement direction between the still images with respect to the specified pixel in the still image, and a displacement direction at each of the specified observation points And a third step of specifying a deformation mode related to a region connecting the observation points of the structure.
Further, the mode analysis method of the present invention includes a first step of photographing a plurality of observation points in a structure with a digital video camera group, and a video regarding each observation point obtained by the photographing, between each digital video camera. A second step of extracting still images every predetermined time starting from a predetermined point in time synchronized, and specifying a displacement direction between the still images with respect to a predetermined pixel in the still image; and each of the specified observations And a third step of identifying a deformation mode related to a region connecting the observation points of the structure based on a displacement direction at the point, and in the first step, in a shooting range of the digital video camera group In the second step, a frame in which the light emission at the light emission start time by the light emitting device is reflected in the second step is displayed on each digital image. Identify a predetermined time when the synchronization is taken between Le video camera, and extracts a still image for each predetermined time frame as a starting point.

  In the present invention, it is not necessary to perform measurement by installing measuring devices such as sensors at multiple points as in the past, and the labor and cost for assembling a temporary structure such as a scaffold around the structure are also suppressed. Will be. Further, even in a situation where the absolute value of the displacement amount at the observation point is difficult to measure and only the displacement direction can be specified, the deformation mode of the structure can be specified efficiently and reliably. Therefore, according to the present invention, it is possible to perform mode analysis with good accuracy simply and at low cost.

  The mode analysis method may include a fourth step of specifying the vibration mode by continuing the specified deformation modes in time series. According to the present invention, it is possible to specify a vibration mode in a structure having a length in a direction orthogonal to the vibration amplitude direction, and obtain information for confirming the state of the structure and the behavior with respect to external force in more detail. can do.

  In addition, in the second step of the mode analysis method, still images for every predetermined time are started from a predetermined point in time synchronized between the respective digital video cameras from the video regarding each observation point obtained by the photographing. Extracting and calculating a displacement amount for each predetermined time at each observation point by specifying a displacement between each still image with respect to a predetermined pixel in the still image, and in the third step, calculating each of the calculated observations A deformation mode related to a region connecting the observation points of the structure may be specified based on a displacement amount at a predetermined time at the point. According to the present invention, the deformation mode can be accurately identified based on the absolute value of the displacement amount.

  Further, in the fourth step of the mode analysis method, the vibration mode may be specified by continuing the deformation mode specified for the region based on the displacement amount for each predetermined time in time-series order. According to the present invention, as described above, the vibration mode can be accurately identified based on the absolute value of the displacement amount.

Conventionally, in order to synchronize between measuring devices, for example, a method of simultaneously sending electrical signals to measuring devices has been used, but since synchronization in microseconds is required, it is unique to each measuring device. Therefore, it is quite difficult to achieve accurate synchronization due to problems such as differences in operation time and network delay. However, in the first step, light emission by the light emitting device is performed toward the shooting range of the group of digital video cameras, and in the second step, the light emission start time by the light emitting device of the frames constituting the video is determined. If the frame in which the light is reflected is identified as a predetermined point in time between each digital video camera and a still image is extracted every fixed time from this frame , each digital video camera Regardless of the difference inherent in the frame, it is possible to specify a frame shot at the same time between digital video cameras as a starting point. For each digital video camera that is in a position where the light emitted from the light emitting device cannot be directly photographed, a reflective material such as a mirror for guiding the light emission is appropriately installed between the light emitting device and the digital video camera. The reflected light may be guided to the shooting area of the digital video camera.

  In the first step of the mode analysis method, the light emission by the light-emitting device toward the shooting range of the digital video camera group is a short-time light emission for only a predetermined time. In the second step, Among the frames constituting the video, the frame in which the light emission by the light emitting device is reflected for a short time is identified as a predetermined point in time that is synchronized with each digital video camera, and the frame is set as a starting point and stationary at regular intervals. An image may be extracted. In this way, if the light emission by the light emitting device is a short time light emission, such as a flash light emission, the number of frames in which the light emission is reflected becomes limited, and the distinction from other frames becomes clear. It becomes possible to reliably specify a predetermined point in time in which the digital video cameras are synchronized.

In addition, the mode analysis system of the present invention includes a digital video camera group that captures a plurality of observation points that are a plurality of predetermined locations exposed on the surface among the parts constituting the structure, and an information processing device, and the information processing apparatus extracts a still image for each of the digital video camera unit from the image for each observation point obtained by photographing a predetermined time synchronization a predetermined time taken to origin among the digital video cameras, said plurality A process for specifying a pixel on the still image corresponding to the observation point, a process for specifying a displacement direction between the still images with respect to the specified pixel in the still image, and each specified observation point And a process of specifying a deformation mode relating to a region connecting the observation points of the structure based on the displacement direction at the point.

  According to the present invention, it is possible to perform mode analysis with good accuracy simply and at low cost.

It is explanatory drawing of the mode analysis system in this embodiment. It is a figure which shows the hardware structural example of each apparatus which comprises the mode analysis system in this embodiment. It is explanatory drawing which shows the example of a process sequence of the mode analysis method of this embodiment. It is explanatory drawing which shows the example of the binarized image of this embodiment. It is explanatory drawing which shows the example of a displacement of this embodiment. It is explanatory drawing which shows the process result example 1 of this embodiment. It is explanatory drawing which shows the process result example 2 of this embodiment. It is explanatory drawing which shows the process result example 3 of this embodiment.

--- System configuration example ---
Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an explanatory diagram of a mode analysis system 10 in the present embodiment. The mode analysis system 10 according to the present embodiment performs mode analysis with good accuracy simply and at low cost, and includes an information processing apparatus 100 and a plurality of digital video cameras 200 as shown in FIG.

  Here, the bridge girder 2 of the bridge 1 is illustrated as a structure to be analyzed. If a moving body having a predetermined weight such as a vehicle or a railway passes through the bridge 1, the bridge girder 2 will vibrate or sink in the vertical direction depending on the weight of the moving body or the magnitude of the moving speed. . When diagnosing the soundness of the bridge 1 or grasping the vibration mode, it is important to observe the displacement of the bridge girder 2 and obtain the amount of displacement. However, even in the case where the absolute value of the displacement amount cannot be measured and only the displacement direction can be observed, the mode analysis method of the present embodiment reveals the deformation mode and the vibration mode, and the structure to be analyzed Since the tendency of displacement becomes clear, it is technically significant.

  By the way, among the members constituting the bridge 1, the bridge girder 2 often includes, for example, H-shaped steel 4. The H-shaped steel 4 is a member whose specifications are standardized, and the dimensions of each part are already known. The H-shaped steel 4 is passed between the bridge piers 7, and the end portions 6 of the flanges 5 which are the side surfaces thereof are exposed on the side surfaces 3 of the bridge girder 2. The thickness of the flange end 6 is determined according to the specification, that is, it can be said that the vertical dimension is known.

  In the present embodiment, the digital video camera 200 is arranged on each of a plurality of flange end portions 6 (that is, a plurality of observation points) spaced apart at a certain distance in the H-beam 4 in the bridge girder extension direction, for example, to display an image. The amount of displacement is calculated by photographing, and the mode analysis is performed. Of course, it is good also considering the predetermined location of members other than the H-shaped steel which comprises the bridge girder 2 as an observation point.

  Therefore, the digital video camera 200 is arranged around the bridge 1 by the number of the observation points, for example. Of course, a digital video camera 200 that places a plurality of observation points (flange end 6) out of all observation points in the photographing range at a time is arranged, and a digital video camera group is configured with the digital video cameras 200 that are equal to or less than the total number of observation points. It is good.

  It is preferable that the mode analysis system 10 includes a light emitting device 300 that emits light toward the photographing range of the digital video camera group. As the light emitting device 300, for example, a flash used at the time of camera photographing can be adopted. The light emitted by the light emitting device 300 is reflected in the video taken by the digital video camera 200. The light emission reflected in the video serves as a mark at a predetermined point in time when the digital video cameras are synchronized during processing by the information processing apparatus 100 described later. That is, the information processing apparatus 100 identifies the frame in which the light emission is reflected among the frames constituting the video as the predetermined time point when the digital video cameras are synchronized. Therefore, the light emission time in the light emitting device 300 is adjusted to be very short so that the light emission is not performed over a plurality of frames so that the light emission is performed within the photographing time of one frame indicated by the frame rate.

  Note that it is preferable that the light emission time by the light emitting device 300 is as short as the above-mentioned flash because frame identification is easy, but this embodiment can be executed even if the light emission time is not as short as the flash. . This is because the frame in which the reflection of light emission has started can be specified as a frame that is synchronized between the digital video cameras.

  As shown in the figure, when there is a possibility that the light emitted from the light emitting device 300 does not fall within the shooting range of the digital video camera 200, the light emitted from the light emitting device 300 reaches the digital video camera 200 while avoiding an obstacle or the like. The mirror 400 may be arranged as a reflective material at an appropriate position so that it can be done. By adopting such a form, even if the surroundings of the structure are so narrow that it is difficult to arrange the digital video camera 200, or there are many traffic and obstacles, it is flexible to this. Corresponding to the above, the light emission from the light emitting device 300 can be guided to the digital video camera 200. As a result, the above-mentioned predetermined opportunity can be specified more reliably.

  Conventionally, in order to synchronize between measurement devices, for example, a method such as simultaneous notification of electrical signals to measurement devices has been used, but synchronization in microseconds is required, but it is unique to each measurement device. Therefore, it is quite difficult to achieve accurate synchronization due to problems such as differences in operation time and network delay. However, by using the light emission of the light emitting device 300 as described above, it is possible to specify the frame shot at the same time between the digital video cameras as the starting point regardless of the differences inherent in each digital video camera. .

  Subsequently, the hardware configuration of each device constituting the mode analysis system 10 of the present embodiment will be described in detail. FIG. 2 is a diagram illustrating a hardware configuration example of each device configuring the mode analysis system 10 in the present embodiment. The information processing apparatus 100 that constitutes the mode analysis system 10 of this embodiment includes a storage unit 101 that is a non-volatile storage device such as a hard disk drive, a memory 103 that is a volatile storage device such as a RAM, and a program 102 of the storage unit 101. The data is exchanged with an arithmetic unit 104 as a CPU that reads and executes the memory 103, an input unit 105 such as a keyboard and a mouse that receives instructions from a user, an output unit 106 such as a display device and a speaker that outputs processing results, and other devices. The interface unit 107 is provided.

  The digital video camera 200 that constitutes the mode analysis system 10 together with the information processing apparatus 100 is a video camera that can shoot moving images at a predetermined frame rate, and of course has a general configuration that should be provided as a video camera. Yes. This digital video camera 200 executes various information processing such as digital processing of video data in addition to the optical system device 209 for photographing and the storage medium 210 for video data (various recording media and their reader / writers, hard disk drives, etc.) A computer chip is provided. This computer chip exchanges data with a storage unit 201 that is a non-volatile storage device, a memory 203 that is a volatile storage device, a calculation unit 204 that is a CPU that reads and executes the program 202 from the storage unit 201, and other devices. The interface unit 207 is included.

  Subsequently, a process realized by the execution of the program 102 by the arithmetic unit 104 of the information processing apparatus 100 configuring the mode analysis system 10 will be described. The information processing apparatus 100 acquires, for example, video data regarding each flange end portion 6 obtained by each digital video camera 200 by photographing a predetermined area including a plurality of flange end portions 6 from the interface unit 207 of each digital video camera 200. Then, a still image is extracted from the video data at a predetermined time starting from a predetermined time point when the digital video cameras are synchronized, and a displacement between the still images with respect to a predetermined pixel in the still image is extracted. A process for specifying a direction or a process for calculating the displacement amount at each observation point by specifying a displacement between the still images is executed. When the absolute value of the displacement amount is obtained, it is preferable to execute the process of calculating the displacement amount for each predetermined time at each observation point because the deformation mode and the vibration mode can be specified with high accuracy.

  Note that the information processing apparatus 100 executes a process of performing binarization processing on an image in a predetermined range including the flange end 6 in each extracted still image. The image binarization process is a process of assigning each pixel to black and white, for example, white if the pixel density information is smaller than a certain threshold value, and black if it is larger than the certain threshold value. A conventional method may be adopted as the binarization processing method itself. The program 102 includes a program for executing such binarization processing.

  The digital video camera 200 receives a video data acquisition request from the information processing apparatus 100 at the interface unit 207, reads video data from the storage medium 210 in response to this request, and passes this through the interface unit 207. It transmits to the information processing apparatus 100. Alternatively, the video data read by the reading device from the storage medium 210 by the user setting the storage medium 210 of each digital video camera 200 to a predetermined reading device connected to the interface unit 107 of the information processing apparatus 100. May be sent to the information processing apparatus 100.

  Further, the information processing apparatus 100 identifies the flange end 6 in the binarized image of the predetermined range, and a displacement in units of the number of pixels between the still images of the identified flange end 6. A process of calculating a displacement amount of the flange end 6 based on the known dimensions is executed. Unlike the flange end 6, when the actual dimension to be analyzed is not known in advance and the displacement amount calculation process cannot be performed, the information processing apparatus 100 is, for example, from a predetermined reference position in a still image. Processing for determining the displacement direction of the pixel is performed. As an example of the reference position, it is possible to assume a position of a linear axis extending vertically or horizontally including the center of gravity of the analysis target in the still image. The information processing apparatus 100 determines whether the corresponding pixel is located above, below, left, or right of the reference position, and can identify that the pixel is displaced in the direction of the corresponding position when viewed from the reference position.

  The processing for specifying the flange end 6 in the binarized image of the predetermined range includes a case where the information processing apparatus 100 specifies the image by receiving the designation of the corresponding image from the user at the input unit 105, for example. Alternatively, the information processing apparatus 100 holds the shape pattern data of the flange end portion 6 (for example, data such as the length and drawing angle of each line segment when the flange end portion 6 is drawn) in the storage unit 101, There may be a case where an image recognition process is performed in which an aggregate of black pixels matching the shape pattern is recognized as the flange end 6.

  Further, the displacement in units of the number of pixels between the still images of the specified flange end 6 is, for example, the coordinate value of the pixel corresponding to the flange end 6 on the coordinate plane of each still image, for a predetermined time interval. The still images are compared, and the distance between the coordinate values of each still image is calculated. Naturally, since the displacement amount of the pixel does not directly become the displacement amount of the flange end portion 6, the information processing apparatus 100 stores a coefficient value indicating the displacement amount per unit pixel from the number of pixels with respect to the known dimension value. The distance between the coordinate values of each still image, that is, the displacement amount of the pixel may be multiplied by the coefficient value to calculate the displacement amount of the flange end 6.

  Further, the information processing apparatus 100 specifies a deformation mode related to a region connecting the flange ends 6 of the bridge 1 based on the displacement direction at the specified flange ends 6 or the calculation. Based on the amount of displacement at each flange end portion 6 at a predetermined time, the deformation mode relating to the region connecting the flange end portions 6 of the bridge 1 is specified. Further, the information processing apparatus 100 specifies the vibration mode by continuing the specified deformation mode in time series order, or sets the deformation mode specified for the region based on the displacement amount for each predetermined time in time series. The vibration mode is specified in the sequence. Details of the processing for specifying such deformation mode and vibration mode will be described later.

  Here, an example in which a necessary function is implemented by executing a program by a calculation unit such as a CPU has been described. However, the information processing apparatus 100 and the digital video camera 200 include an electronic circuit or the like that realizes a necessary function. Of course, there is no problem even if the same processing is executed.

--- Example procedure of mode analysis method ---
Next, the processing procedure of the mode analysis method in this embodiment will be described. FIG. 3 is an explanatory diagram illustrating a processing procedure example of the mode analysis method according to the present embodiment. First, the digital video camera 200 is installed with the lens facing each of the flange end portions 6 existing at various locations of the bridge girder 2 to be analyzed (s100). The distance between the flange end 6 and the digital video camera 200 is a distance at which the flange end 6 can be photographed with a predetermined resolution in the telephoto photographing function of the digital video camera 200. Needless to say, the installation height of the digital video camera 200 and the upper, lower, left and right lens angles are adjusted so that the flange end 6 of the H-shaped steel 4 in the bridge girder 2 is within the photographing range.

  It is preferable that the interface unit 207 of the digital video camera 200 installed as described above and the interface unit 107 of the information processing apparatus 100 are connected so as to be able to exchange data using a predetermined communication cable or wireless communication means. .

  Each digital video camera 200 receives an instruction from the person in charge of observation through, for example, infrared communication from a remote controller, and starts photographing the flange end 6 that is responsible for photographing (s101). Alternatively, the digital video camera 200 may detect the arrival of a certain time set in advance by the timer function 206 provided by the digital video camera 200 and start shooting autonomously. In addition, the light emitting device 300 receives the instruction from the person in charge of observation in the same manner as the digital video camera 200, and performs a light emitting operation for a predetermined time after a predetermined time from the reception of the instruction (s102). The reason why the light emission operation is performed after a certain period of time is to estimate the timing at which shooting is started in all the digital video cameras 200 so that each digital video camera 200 constituting the digital video camera group can reliably capture the light emission. There is intention.

  Each digital video camera 200 stores the obtained video data in the storage medium 210 as the shooting progresses. Naturally, the light emission from the light emitting device 300 is reflected in any frame constituting the video data. Each digital video camera 200 may upload video data to the information processing apparatus 100 connected via the interface unit 207 at regular time intervals or in real time.

  On the other hand, the information processing apparatus 100 notifies each digital video camera 200 of a video data acquisition request (s103). On the other hand, each digital video camera 200 receives a video data acquisition request from the information processing apparatus 100 at the interface unit 207, reads video data from the storage medium 210 in response to this request, and passes this through the interface unit 207. The information is transmitted to the information processing apparatus 100 (s104). Alternatively, the video data read by the reading device from the storage medium 210 by the user setting the storage medium 210 of each digital video camera 200 to a predetermined reading device connected to the interface unit 107 of the information processing apparatus 100. May be sent to the information processing apparatus 100.

  In this way, the information processing apparatus 100 acquires video data regarding a predetermined area including the flange end 6 from the digital video camera 200 (s105) and stores it in the storage unit 101. In addition, the information processing apparatus 100 reads out the video data acquired in the step from the storage unit 101 at regular intervals, and at a predetermined time when the digital video cameras are synchronized, that is, at the time when the light emitting device 300 starts to emit light. Starting from a frame in which light emission is reflected, a still image of each frame is extracted every predetermined time such as 1/30 seconds (s106). Existing technology may be applied to the process of extracting a still image from a moving image.

  Next, the information processing apparatus 100 performs binarization processing on an image in a predetermined range including the flange end portion 6 of the H-shaped steel 4 in each still image extracted in the step (s107). The binarization processing of the image is performed by, for example, comparing the value indicated by the shading information (contrast information) of the pixel with a certain threshold, white if the shading value is smaller than the threshold, and black if the shading value is greater than the threshold. In addition, each pixel is divided into two colors, black and white. A conventional method may be adopted as the binarization processing method itself. The program 102 includes a program for executing such binarization processing.

  Subsequently, the information processing apparatus 100 identifies the flange end 6 in the image in the predetermined range binarized in the step (s108). In the process of specifying the flange end 6 in the binarized image of the predetermined range (see FIG. 4), the information processing apparatus 100 designates the corresponding image from the user (for example, range designation or element) using the input unit 105, for example. For example). Alternatively, the information processing apparatus 100 stores data on the shape pattern of the flange end 6 (eg, data such as the length of each line segment, the distance between line segments, and the drawing angle when the flange end 6 is drawn). In other words, an image recognition process may be performed in which an aggregate of black pixels matching the shape pattern is recognized as the flange end 6.

  The information processing apparatus 100 calculates the displacement amount of the flange end portion 6 based on the displacement in units of the number of pixels between the still images of the flange end portion 6 specified in the step and the known dimensions. (S109). The displacement in units of the number of pixels between the still images of the flange end 6 is, for example, the coordinate value of the pixel corresponding to the flange end 6 on the coordinate plane of each still image, between the still images at fixed time intervals. And calculating the distance between the coordinate values of each still image. Naturally, since the displacement amount of the pixel does not directly become the displacement amount of the flange end portion 6, the information processing apparatus 100 stores a coefficient value indicating the displacement amount per unit pixel from the number of pixels with respect to the known dimension value. The distance between the coordinate values of each still image, that is, the displacement amount of the pixel may be multiplied by the coefficient value to calculate the displacement amount of the flange end 6.

  For example, as shown in the example of FIG. 5, the coordinate value (10, 10) of the predetermined pixel x of the flange end 6 in the still image at time A, the still image at time B 1/30 seconds after time A. The coordinate value (10, 12) of the predetermined pixel x is assumed. In this case, it can be seen that the pixel x has moved in the vertical direction by “12−10” = 2 pixels within 1/30 seconds. When the vertical dimension of the flange end 6, that is, the actual thickness of the flange end 6 is, for example, 20 mm, and the number of pixels indicating the corresponding part in the still image is 100 pixels, The actual dimension value of the flange end 6 is 0.2 (mm). This is a value corresponding to the actual displacement per unit pixel displacement in the vertical direction, and the information processing apparatus 100 holds this value in the storage unit 101 in advance as a coefficient value. In this case, the information processing apparatus 100 multiplies 2 pixels, which is the displacement amount of the pixel x, by 0.2, which is the coefficient value, to obtain the displacement amount of the flange end portion 6 between the time points A and B. Calculated as 2 × 0.2 ″ = 0.4 (mm). As described above, the pixel displacement in the image and the actual displacement at the flange end 6 both coincide in the vertical direction, and the actual displacement amount of the flange end 6 per unit pixel displacement is also specified. Therefore, even when the image is taken from the oblique lateral direction without facing the flange end 6, for example, the displacement amount calculation without error can be performed based on the obtained image.

  Of course, instead of calculating the displacement amount of the flange end 6 for each frame as described above, focusing on the displacement in a relatively long time span such as sinking, for example, the displacement amount at intervals of 0.5 seconds A processing form in which calculation is performed may be employed.

  The information processing apparatus 100 executes the process of step s109 described above for all still images obtained from the video data regarding each observation point, that is, each flange end 6 (s110). The processing result here is a line graph showing the displacement amount of each flange end 6 for each elapsed time, as in the graph shown in FIG.

  The information processing apparatus 100 recognizes the position of each flange end 6 in each time zone based on the displacement amount in each flange end 6 in each time zone thus obtained, and connects these flange end portions 6. The shape for every linear time zone comprised by these, ie, a deformation | transformation mode, is specified (s111: refer FIG. 7). As shown in FIG. 7, there is a distribution of displacement not only in the bridge axis direction but also in the bridge width direction, and mode analysis is possible in any direction. Further, the information processing apparatus 100 may specify the vibration mode of the bridge girder 2 by continuing the deformation modes in chronological order (s113). In the example of FIG. 7, a vibration mode in which the deformation mode transitions according to conditions from a no load state through which a vehicle or the like does not pass is illustrated. In the bridge girder 2, the vibration mode changes depending on various conditions such as the weight and passage interval of a passing vehicle, and a continuous passing event of a plurality of vehicles having different weights and sizes. The extended shape of the bridge girder 2 varies depending on the location, such as a straight line or a curve, an uphill or downhill, or a combination thereof, but the vibration mode also changes depending on such conditions. In the mode analysis system 10 according to the present embodiment, the mode analysis can be easily and reliably performed by photographing with the digital video camera 200 and information processing by the information processing apparatus 100. Even if there is, it can be applied without problems and high-precision mode analysis can be realized.

  The information processing apparatus 100 displays the deformation mode and vibration mode information specified in the above step on the output unit 106 (s112), and ends the flow.

  In addition to the bridge 1, as the structure to be subjected to mode analysis, for example, various buildings, pipes, and overhead lines can be assumed. For example, when the mode analysis is performed on the deformation occurring in the building, as illustrated in FIG. 8, the vibration mode (mode A in the drawing) in which the entire building protrudes from the middle floor or the building upper floor, as illustrated in FIG. A mode analysis result such as a vibration mode (mode B in the figure) in which the is swung to the side is obtained. In buildings, it is difficult to observe displacement because the displacement behavior may extend over the entire building, and it may not be easy to measure the absolute value of the displacement amount like the bridge girder 2 above, but the mode analysis method of this embodiment is adopted. For example, a displacement direction for a predetermined time at a predetermined observation point (for example, a displacement direction based on a predetermined axis passing through a building up and down) is specified, and the deformation directions are connected by connecting the displacement directions of the respective observation points specified here. Information can be obtained.

  In this case, the information processing apparatus 100 determines whether the predetermined pixel in each still image where the building is photographed is located on the left or right side of the reference position, and the pixel in the direction of the corresponding position as viewed from the reference position, that is, It can be specified that a predetermined part of the building has been displaced. Therefore, it becomes clear which direction the predetermined pixel in the still image has moved in a certain time zone. If a line segment is connected at each location where the displacement direction is found in this way, assuming that there is a displacement in the movement direction from the reference position, information on the deformation mode similar to that illustrated in FIG. 7 can be obtained. Further, if this deformation mode is continued in time series order, the vibration mode can be specified.

  According to the present embodiment as described above, it is possible to perform mode analysis with good accuracy simply and at low cost.

  Although the embodiment of the present invention has been specifically described based on the embodiment, the present invention is not limited to this, and various modifications can be made without departing from the scope of the invention.

1 Bridge (structure)
2 Bridge girder 3 Bridge girder side 4 H-shaped steel 5 Flange 6 Flange end (observation point)
7 Bridge pier 10 Mode analysis system 100 Information processing apparatus 101 Storage unit 102 Program 103 Memory 104 Operation unit 105 Input unit 106 Output unit 107 Interface unit 200 Digital video camera 201 Storage unit 202 Program 203 Memory 204 Calculation unit 206 Timer function 207 Interface unit 300 Light emitting device 400 mirror

Claims (7)

A first step of photographing with a digital video camera group a plurality of observation points that are a plurality of predetermined locations exposed on the surface among the parts constituting the structure;
From the video about each observation point obtained by the photographing, a still image is extracted every predetermined time starting from a predetermined time point when the digital video cameras are synchronized, and the still images corresponding to the plurality of observation points are extracted. An observation point identifying step for identifying pixels on the image;
A second step of specifying a displacement direction between the still images with respect to the specified pixel in the still image;
A mode analysis method comprising: a third step of identifying a deformation mode related to a region connecting the observation points of the structure based on a displacement direction at each of the identified observation points. A first step of photographing a plurality of observation points in the structure with a group of digital video cameras;
A still image for each predetermined time is extracted from a predetermined point in time synchronized between the digital video cameras from the video regarding each observation point obtained by the photographing, and each still image for a predetermined pixel in the still image is extracted. A second step of identifying the direction of displacement between the two,
A third step of identifying a deformation mode related to a region connecting the observation points of the structure based on a displacement direction at each of the identified observation points;
Only including,
In the first step, the light emitting device emits light toward the photographing range of the digital video camera group,
In the second step, among the frames constituting the video, the frame in which the light emission at the light emission start time by the light emitting device is reflected is identified as a predetermined time point in which synchronization between the digital video cameras is taken, A mode analysis method characterized in that still images are extracted at regular intervals from this frame . In the first step, the light emission by the light emitting device toward the shooting range of the digital video camera group is a short time light emission of only a predetermined time,
In the second step, among the frames constituting the video, a frame in which light emission by the light emitting device is reflected for a short time is identified as a predetermined time point when synchronization between the digital video cameras is taken, and this frame The mode analysis method according to claim 2 , wherein still images are extracted every predetermined time from the starting point. The mode analysis method according to any one of claims 1 to 3, further comprising a fourth step of specifying the vibration mode by continuing the specified deformation modes in time series. In the second step, a still image for each predetermined time is extracted from a video about each observation point obtained by the shooting from a predetermined time point when synchronization between the digital video cameras is taken, By calculating the displacement between each still image with respect to the predetermined pixel in, the amount of displacement per predetermined time at each observation point,
In the third step, based on the calculated displacement amount for each predetermined time at each observation point, a deformation mode relating to a region connecting the observation points of the structure is specified.
The mode analysis method according to any one of claims 1 to 3, wherein: 6. The mode analysis according to claim 5 , wherein, in the fourth step, the vibration mode is specified by continuing the deformation mode specified for the region based on the displacement amount for each predetermined time in time-series order. Method. A group of digital video cameras for photographing a plurality of observation points that are a plurality of predetermined locations exposed on the surface among the parts constituting the structure, and an information processing device,
The information processing apparatus includes:
Extracting still images every predetermined time starting from a predetermined point in time synchronized between the digital video cameras, from the video about each observation point obtained by the digital video camera group by photographing, the plurality of the observation points A process of identifying pixels on the still image corresponding to
Processing for specifying a displacement direction between the still images with respect to the specified pixel in the still image;
Based on the displacement direction at each identified observation point, a process for identifying a deformation mode related to a region connecting the observation points of the structure is performed.
A mode analysis system characterized by this.