JP2013007624A - Displacement observation method and displacement observation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply perform accurate displacement observation regarding a bridge girder at low cost.SOLUTION: A displacement observation method includes the steps of: photographing a bridge girder 2 which is an observation target and the side face of a floor slab 7 with a digital video camera 200; extracting still images for every predetermined time from video obtained by photography to perform binarization processing for images within a predetermined range including a flange 5 in the respective still images regarding the flange 5 at a predetermined part, in which a member whose image is included in the still images is H type steel 4, and dimensions in the vertical direction are identified; and specifying a flange end 6 in the images on which the binarization processing is performed within the predetermined range to calculate a displacement amount of the flange 5 on the basis of displacement of unit of the number of pixels among the respective still images at the flange end 6 and the identified dimensions.

Description

  The present invention relates to a displacement observation method and a displacement observation system, and more specifically to a technique for easily and inexpensively observing displacement with good accuracy for bridge girders and floor slabs of bridges.

  Various structures may be deformed by various external forces. When a structure is deteriorated or damaged, such deformation tends to increase. Therefore, it is important to observe deformation to understand the soundness of the structure. As a conventional method, there is a method of constructing a temporary 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 for the observation 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

  Displacement observation technology based on photographed images is superior in terms of enabling so-called remote observation compared to the technology of directly observing measuring instruments installed at the observation location, but some problems remain. ing.

  For example, there is a problem that it is difficult to select an observation location that is a target of image capturing and is a target of displacement amount comparison between captured images. In order to capture the displacement between the captured images with certainty, it is necessary to select a member of an appropriate size that can be captured as an observation location. It is very difficult to consider the correspondence between the pixel displacement at and the movement distance of the actual observation location, that is, the displacement amount. In this case, a displacement with good accuracy cannot be obtained. Furthermore, in the conventional technology, if the imaging is performed by capturing the observation location from the front, the correspondence between the displacement amount between the captured images and the actual displacement amount is simple, and the displacement amount calculation can be performed. If the collimation direction of the imaging means in the above does not face the observation location, it is difficult to determine the correspondence between the displacement amount between the captured images and the actual displacement amount, and it is difficult to determine the displacement amount itself. In particular, the bridge girder passed between the piers with a predetermined span and the floor slab installed on the bridge slab are prone to displacement due to moving objects such as automobiles and railways, and there has been a demand for efficient and reliable displacement observation technology. .

  Accordingly, an object of the present invention is to provide a technique for easily and inexpensively observing a displacement with good accuracy related to a bridge.

  The displacement observation method of the present invention that solves the above problems includes a step of photographing a side surface of a bridge girder or floor slab of a bridge to be observed with a digital video camera, and extracting still images at predetermined time intervals from the image obtained by the photographing. The binarization processing is performed on the image in the predetermined range including the predetermined portion in each still image with respect to the predetermined portion where the image is included in the still image and the vertical dimension is known. A step, an end portion of the predetermined position in the binarized image of the predetermined range, and a displacement in units of the number of pixels between the still images of the specified end portion and the known dimensions And calculating a displacement amount of the predetermined portion based on the above.

  In the present invention, an image of a member including a part whose vertical dimension is previously known from a design book and the displacement direction of which is also a vertical direction, i.e., a bridge girder and a floor slab, is taken, and analysis processing of the photographed image is performed. As a result, the dimensional direction of the pixels in the captured image and the displacement direction at the actual observation location originally match, and the relationship between the displacement amount of the pixel in the captured image and the actual displacement amount at the observation location is also clear. Even if the collimation direction does not face the observation location, the actual displacement can be obtained with good accuracy. As a result, if the vertical displacement of the relevant member is within the range that can be photographed, the digital video camera can be installed and the relevant member can be photographed regardless of the collimation direction, so there are many obstacles around the observation target. Even in such a situation, displacement observation can be realized flexibly in response to such a situation without involving a large-scale temporary construction.

  Therefore, it is possible to perform displacement observation with good accuracy related to the bridge simply and at low cost.

  Note that the displacement observation method may include a step of performing Fourier transform on a displacement amount at a predetermined time for the predetermined location, and calculating a displacement frequency at the predetermined location. According to the present invention, it is possible to specify at what frequency the displacement generated with respect to the observation point is generated, and for example, a countermeasure against displacement according to the frequency can be considered.

  In addition, the displacement observation system of the present invention acquires a digital video camera that captures a side surface of a bridge girder or floor slab of a bridge to be observed, and video data obtained by the digital video camera during the shooting, and predetermined from the video data A predetermined range of images including the predetermined portion in each still image, with respect to a predetermined portion where a still image is extracted every time and the image is included in the still image and the vertical dimension is known. Processing for performing binarization processing on the image, specifying an end portion of the predetermined portion in the binarized image of the predetermined range, and a displacement in units of the number of pixels between the still images of the specified end portion And an information processing device that executes a process of calculating a displacement amount of the predetermined location based on the known dimensions.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to perform a displacement observation with a sufficient precision regarding a bridge simply and at low cost.

It is explanatory drawing of the displacement observation system in this embodiment. It is a figure which shows the hardware structural example of each apparatus which comprises the displacement observation system in this embodiment. It is explanatory drawing which shows the process sequence example of the displacement observation 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.

--- 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 displacement observation system 10 in the present embodiment. A displacement observation system 10 (hereinafter referred to as a displacement observation system 10) according to the present embodiment performs displacement observation with good accuracy on a bridge simply and at low cost. As shown in FIG. The digital video camera 200 is configured. The observation object regarding the displacement is the bridge girder 2 or the floor slab 7 of the bridge 1. If a moving body having a predetermined weight such as a vehicle or a railway passes through the bridge 1, the bridge girder 2 or the floor slab 7 vibrates or sinks according to the weight of the moving body or the magnitude of the moving speed. Become. That is, the bridge girder 2 and the floor slab 7 are displaced in the vertical direction. When diagnosing the soundness of the bridge 1, it is important to observe the displacement of the bridge girder 2 and the floor slab 7 to obtain the displacement amount.

  Of the members constituting the bridge 1, the bridge girder 2 often includes, for example, an 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 piers, and the end portion 6 of the flange 5 which is the side surface thereof is exposed to the side surface 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.

  Therefore, in the present embodiment, as an example, the displacement amount of the end portion 6 of the flange 5 of the H-shaped steel 4 is calculated. Needless to say, any member other than the H-shaped steel constituting the bridge girder 2 or a constituent member of the floor slab 7 whose dimension in the vertical direction is known in advance can be adopted as a displacement amount calculation target.

  Subsequently, the hardware configuration of each device constituting the displacement observation 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 displacement observation system 10 in the present embodiment. The information processing apparatus 100 that constitutes the displacement observation 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 displacement observation 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 displacement observation system 10 will be described. The information processing apparatus 100 acquires, for example, video data obtained by the digital video camera 200 by shooting for a predetermined area including the flange end 6 from the interface unit 207 of the digital video camera 200, and from the video data every predetermined time. Is a member that includes an image in the still image, and is related to a predetermined location where the vertical dimension is known, that is, the flange end 6 of the H-shaped steel 4 in each still image. Processing for performing binarization processing on an image in a predetermined range including the flange end 6 is executed.

  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 transmits this video data to the information via the interface unit 207. It transmits to the processing apparatus 100. Alternatively, the user sets the storage medium 210 of the digital video camera 200 to a predetermined reading apparatus connected to the interface unit 107 of the information processing apparatus 100, and the video data read from the storage medium 210 by the reading apparatus is read out. The information may be sent to the information processing apparatus 100.

  In addition, the information processing device identifies an end portion of the predetermined portion, that is, the flange end portion 6 in the binarized image of the predetermined range, and pixels between the still images of the specified flange end portion 6 A process of calculating the displacement amount of the flange end 6 based on the displacement of several units and the known dimensions is executed.

  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 portion 6 is, for example, the coordinate value of the pixel corresponding to the flange end portion 6 on the coordinate plane of each still image is expressed at a constant 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 become the actual displacement amount of the flange end portion 6 as it is, in this case, the actual displacement amount of the flange end portion 6 (eg, 0 pixel) per unit displacement amount (eg, 1 pixel) of the pixel. .2 mm) is previously stored in the storage unit 101 or the like, and the distance between the coordinate values of each still image, that is, the displacement amount of the pixel is multiplied by the coefficient value, and the flange end The displacement amount of the part 6 may be calculated.

  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 displacement observation method ---
Next, a processing procedure of the displacement observation method in the present embodiment will be described. FIG. 3 is an explanatory diagram illustrating a processing procedure example of the displacement observation method according to the present embodiment. First, the digital video camera 200 is installed with the lens facing the side surface of the bridge girder 2 that is the object of displacement observation (s100). The distance between the bridge beam 2 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. .

  The 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 shooting (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.

  The digital video camera 200 stores the obtained video data in the storage medium 210 as the shooting progresses. Alternatively, the 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 the digital video camera 200 of a video data acquisition request (s102). On the other hand, the digital video camera 200 accepts 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 transmits the video data to the information via the interface unit 207. It transmits to the processing apparatus 100 (s103). Alternatively, the user sets the storage medium 210 of the digital video camera 200 to a predetermined reading apparatus connected to the interface unit 107 of the information processing apparatus 100, and the video data read from the storage medium 210 by the reading apparatus is read out. The information may be sent to the information processing apparatus 100.

  In this way, the information processing apparatus 100 acquires video data relating to a predetermined area including the flange end 6 from the digital video camera 200 (s104) and stores it in the storage unit 101. Further, the information processing apparatus 100 reads out the video data acquired in the step immediately or at regular intervals from the storage unit 101, and extracts a still image of each frame, that is, every predetermined time such as 1/30 second (s105). 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 (s106). 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 end portion of the predetermined portion, that is, the flange end portion 6 in the image of the predetermined range binarized in the step (s107). 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. (S108). 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 performs the process of step s108 described above between the still images obtained from the video data, for example, performs processing on all the still images obtained from the video data, and the processing result Is displayed on the output unit 106 (s109), and the flow ends. As a processing result, there is a line graph indicating the amount of displacement of the flange end 6 for each elapsed time, as in the graph shown in FIG.

  Note that the information processing apparatus 100 may perform Fourier transform on the displacement amount data for each elapsed time as illustrated in FIG. 6 to calculate the displacement frequency at the flange end 6 (s110). In this case, the information processing apparatus 100 is provided with a Fourier transform program in the storage unit 101 in advance, and is called and executed. By executing the Fourier transform, a graph of frequency characteristics as shown in FIG. 7 is obtained from the displacement amount data for each elapsed time, for example. The graph of FIG. 7 shows an example in which the displacement at the flange end 6 occurs at a frequency of 30 Hz. Thus, by determining the vibration frequency of the displacement at the observation location, it is possible to make the bridge management more effective, for example, by taking a resonance countermeasure related to the vibration frequency on the bridge.

  According to the present embodiment as described above, it is possible to perform displacement observation with good accuracy related to the bridge 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.

DESCRIPTION OF SYMBOLS 1 Bridge 2 Bridge girder 3 Bridge girder side 4 H-shaped steel 5 Flange 6 Flange end 7 Floor slab 10 Displacement observation system 100 Information processing apparatus 101 Storage part 102 Program 103 Memory 104 Operation part 105 Input part 106 Output part 107 Interface part 200 Digital video Camera 201 Storage unit 202 Program 203 Memory 204 Calculation unit 206 Timer function 207 Interface unit

Claims (3)

The process of photographing the side of the bridge girder or floor slab of the bridge to be observed with a digital video camera,
A still image is extracted every predetermined time from the video obtained by the shooting, and the still image is a member that includes the image. Performing binarization processing on a predetermined range of images including a predetermined location;
An end portion of the predetermined portion is specified in the binarized image of the predetermined range, and based on the displacement in units of the number of pixels between the still images of the specified end portion and the known dimensions. Calculating a displacement amount of the predetermined portion;
A displacement observation method comprising:   The displacement observing method according to claim 1, further comprising a step of performing a Fourier transform on a displacement amount at a predetermined time for the predetermined portion and calculating a vibration frequency of the displacement at the predetermined portion. A digital video camera that captures the side of the bridge girder or floor slab of the bridge being observed,
The video data obtained by the digital video camera in the shooting is obtained, a still image is extracted from the video data every predetermined time, and the still image includes the image, and the vertical dimension is found. Processing for performing binarization processing on an image in a predetermined range including the predetermined location in each still image with respect to the predetermined location
An end portion of the predetermined portion is specified in the binarized image of the predetermined range, and based on the displacement in units of the number of pixels between the still images of the specified end portion and the known dimensions. An information processing apparatus that executes a process of calculating a displacement amount of the predetermined portion;
A displacement observation system comprising: