JP5532454B2 - 3D displacement measurement system for structures using digital cameras - Google Patents

Description

  The present invention relates to a structure three-dimensional displacement measuring system using a digital camera. More specifically, the present invention relates to a three-dimensional displacement measurement system for a structure over time using a digital camera that manages the progress of cracks and the like generated in the structure.

  Conventionally, when measuring the opening direction dimension (gap) of a crack, measurement was directly performed by a crack scale (measuring instrument having a function similar to a ruler or caliper) or the like. In this method, it was impossible to grasp how the structures on both sides of the crack were displaced simply by measuring the gap.

  Therefore, the present applicant has proposed “a method for measuring crack displacement of a structure using a digital camera” disclosed in Patent Document 1. Japanese Patent Application Laid-Open No. 2004-228561 is a system that grasps and manages crack behavior by numerical information by performing advanced information processing on image data obtained by photographing with a digital camera. Specifically, a dedicated measurement panel (same as shown in FIG. 2A) is attached to both sides of the crack to be measured, respectively, and the situation of the two measurement panels is photographed from the front with a digital camera, The image data is digitized by image processing / statistical processing, and the X-axis direction movement amount and the Y-axis direction movement amount between the calculation points of the measurement panel are obtained as measurement panel positions. In Patent Document 1, data for grasping the behavior tendency of a crack (relative of two measurement panels) is obtained by periodically repeating photographing and comparing the calculated and extracted measurement panel position with an initial registration value. 2D displacement amount) is calculated and displayed / recorded.

Japanese Patent Laid-Open No. 2002-340529 “Method for Measuring Crack Displacement of Structure Using Digital Camera” (Release Date: November 27, 2002) Applicant: Nippon Koei Co., Ltd. (Patent No. 4683516)

  In Patent Document 1, two measurement amount panels are fixed to both sides of a crack of a structure, and the relative displacement of the measurement amount panel is grasped by two-dimensional numerical data. However, the displacement on both sides of the crack is essentially displaced in a three-dimensional space. For example, when the crack is viewed in the vertical direction, the direction perpendicular to the crack is the X direction, the direction along the crack is the Y direction, and the direction perpendicular to the surface of the structure with the crack is the Z direction. In the case of uplift or depression, the z value greatly changes in the three-dimensional data (x, y, z value) even when almost no change is seen in the two-dimensional numerical data (x, y value).

  In the crack displacement measurement method disclosed in Patent Document 1, in order to grasp the relative displacement amount of the measurement panel with two-dimensional numerical data, the behavior as an entity such as a crack (that is, the behavior captured in three dimensions) is grasped. It is not possible. Therefore, it has been desired to develop a three-dimensional displacement measurement system for structures that can grasp the actual behavior of cracks and the like.

  Accordingly, an object of the present invention is to provide a three-dimensional displacement measuring system for structures and the like that can be configured with easily adoptable devices without requiring special devices.

  A three-dimensional displacement measurement system using a digital camera according to the present invention is installed at each of relatively displaced locations on the surface of an object to be measured, each of two measurement panels each displaying a grid line, and the measurement A digital camera that photographs the panel from two directions and a data processing device that processes image data of the digital camera, the data processing device image-processing the image data of the digital camera based on the grid lines Means for correcting the angle of the image data to calculate a photographing angle and a focal length; and defining an X-axis direction and a Y-axis direction with reference to the grid line, and further, a direction perpendicular to the XY plane is defined as Z When the axial direction is defined, the X-axis direction distance, Y-axis direction distance between the two measurement panels, the Z-axis direction distance, Z, based on the image-processed image data, angle processing data, and focal length data. And a means for calculating the direction distance and linear distance.

  Further, in the three-dimensional displacement measuring system, the digital camera may have an effective recording pixel number of at least 3 million pixels.

  Furthermore, in the three-dimensional displacement measuring system, the calculation point may be an intersection of the grid lines.

  Further, in the above three-dimensional displacement measurement system, the measurement panel may further display a barcode, and the data may be processed into a database based on the barcode.

  Further, the three-dimensional displacement measurement system further includes a template formed of a transparent member that covers the two measurement panels at the time of photographing, and an inclined guide line is drawn on the template. Sometimes, the photographing frame of the digital camera may coincide with the inclined guide line so that photographing from a desired direction can be performed.

  Furthermore, in the three-dimensional displacement measuring system, the object to be measured may include a building, a civil engineering structure, a rock, a dangerous slope, and an active volcano.

  Furthermore, in the three-dimensional displacement measurement system, imaging from the two directions may be performed by moving the digital camera in the XZ plane without moving the digital camera in the Y-axis direction.

  Further, in the above three-dimensional displacement measurement system, photographing from the two directions may be performed by moving the digital camera in the YZ plane without moving the digital camera in the X-axis direction.

  Furthermore, the three-dimensional displacement measuring method using the digital camera according to the present invention uses two measuring panels that are respectively installed at relatively displaced positions on the surface of the object to be measured and each display a grid line. Further, in the three-dimensional displacement measuring method using a digital camera, two measurement panels each displaying a grid line, each installed at a position relatively displaced from the surface of the object to be measured, are digital cameras. The image data from the digital camera is image-processed based on the grid lines, the angle is further corrected to calculate the shooting angle and the focal length, and the X axis between the two measurement panels A direction distance, a Y-axis direction distance, a Z-axis direction distance, and a straight line distance are calculated.

  Furthermore, in the three-dimensional displacement measuring method, the image from the two directions may be imaged by moving the digital camera in the XZ plane without moving the digital camera in the Y-axis direction.

  Further, in the above three-dimensional displacement measuring method, the photographing from the two directions may be performed by moving the digital camera in the YZ plane without moving the digital camera in the X-axis direction.

  Furthermore, a computer program according to the present invention is a computer program for causing a computer to execute a three-dimensional displacement measuring method using the digital camera.

  Furthermore, a recording medium according to the present invention is a computer-readable recording medium on which the above computer program is recorded.

  According to the present invention, it is possible to provide a three-dimensional displacement measurement system for a structure or the like that can be configured with an easily adoptable device without requiring a special device.

FIG. 1 is a diagram illustrating an overall configuration of a three-dimensional displacement measurement system according to the present embodiment. FIG. 2A is a diagram showing a preferred measurement panel. FIG. 2B is a diagram illustrating a state in which two measurement panels are fixed on both sides of a crack generated on the inner wall of the tunnel. FIG. 3 is a diagram for explaining four elements obtained from calculation points and calculation results of two measurement panels. FIG. 4A is a diagram illustrating a state where the measurement panel is photographed at the photographing angle α by the camera. The lower row is the image. FIG. 4B is a diagram illustrating a template formed of a transparent member such as acrylic and disposed on the measurement panel at the time of photographing. FIG. 4C is a diagram illustrating a work flow at the time of shooting in the field. FIG. 5 is a diagram for explaining the outline of the processing method of the image processing software “crack ruler digital image simple calculation / management system (3D)”. FIG. 6 shows, as an example of calculation points, grid line intersections R1, R2, R3, R4 of one measurement panel and grid line intersections L1, L2, L3, L4 respectively corresponding to the other measurement panel. It is a figure explaining. FIG. 7A shows the situation at the time of shooting with the camera facing from the direction of the shooting angle α in the upper row, and the lower row shows the shot image at that time. FIG. 7B shows a case where angle correction for restoring a distorted panel frame to a square is performed, and the lower part shows a corrected image at that time. FIG. 8 is a diagram showing the state in which the measurement panels 20-1 and 20-2 are displaced in the Z-axis direction in the upper stage, and the images obtained by shooting the right and left directions respectively in the lower stage. FIG.

  Hereinafter, embodiments of a three-dimensional displacement measurement system for a structure using a digital camera according to the present invention will be described in detail with reference to the accompanying drawings. In addition, this embodiment is an illustration of this invention, Comprising: The scope of the present invention is not limited at all.

[Entire system]
FIG. 1 is a diagram showing an overall configuration of a structure three-dimensional displacement measuring system 1 according to the present embodiment. The three-dimensional displacement measuring system 1 of this structure typically has two markers (markers) on both sides of a crack, for example, with respect to the progress of a crack generated in a tunnel or the like, and uses a digital camera for time. It is a system that numerically manages the progress of cracks by capturing the relative displacement between markers in three dimensions in three dimensions.

  As shown in FIG. 1, the overall configuration of the three-dimensional displacement measuring system 1 includes a set of two measurement panels 20 as markers and a set of two measurement panels fixed to an object to be measured. A digital camera 30 for photographing, a data processing device (computer) 40 for performing image processing and arithmetic processing on image data of the digital camera, a monitor 50, an HDD 60, and an optical disk drive 70 connected to the data processing device are provided.

  In the data processing device 40, processing is performed along steps programmed as “three-dimensional image measurement processing software” described later. This processing software may be stored in advance in the internal storage device of the data processing device 40, or may be recorded on a CD, DVD, etc. and loaded from the optical disk drive 70 to the data processing device 40 for each processing. .

  As the structure, etc., buildings such as buildings, bridges, etc. where cracks are expected to occur, and civil engineering structures such as tunnels, roads, etc. are targeted. As cracks and the like generated in structures and the like, cracks that are currently in progress and cracks that are suspected to progress (hereinafter collectively referred to as “progressive cracks”) are targeted. However, cracks are only examples. Even if there are no cracks, it is also applicable to structures that are expected to have a relative displacement over time in three dimensions when two markers are installed. It becomes. In addition, rocks that are expected to collapse, dangerous slopes, grounds such as active volcanoes, etc. are also covered. In the present application documents, these are collectively referred to as “device under test”.

  Regarding the two markers placed on the object to be measured, the number is not limited to two. In the case of three or more markers, the relative displacement between two markers selected from them is obtained, and this is sequentially repeated to determine the relative displacement of other markers with respect to one reference marker, or the first marker Also included is a system for determining an incremental relative displacement, such as a relative displacement of the second marker relative to, a relative displacement of the third marker relative to the second marker.

  In this specification, in order to explain the three-dimensional displacement measuring system of this embodiment in an easy-to-understand manner, a system for measuring the three-dimensional relative displacement on both sides of a progressive crack generated in a tunnel using two markers. Will be described as an example. Each component will be described.

[Each component]
(Measurement panel)
The measurement panel is an object that serves as a marker (marker) when photographed with a digital camera. FIG. 2A is a diagram showing a preferred measurement panel 20. This measurement panel 20 is the same as registered design No. 1389057 (article related to design: crack measurement panel) in which the present applicant is a design right holder. The measurement panel 20 has 4 × 4 squares 10 mm on each side drawn by vertical and horizontal grid lines 24 and 25 drawn at intervals of 10 mm in a square display area 27 having a side of 50 mm. ing.

  On the measurement panel 20, a bar code 22 for specifying each measurement panel is displayed. In the data processing, by using the barcode 22, data of the tunnel where the measurement panel 20 is installed (location, installation date and time, serial number when a plurality of sets of measurement panels are installed), initial measurement Data and subsequent measurement data, etc. can be classified, organized, and processed into a database.

  In addition, the measurement panel 20 is formed with an anchor hole 21 used for installation in a tunnel, a caliper measurement hole 23 for auxiliary confirmation of data, and the like.

  Since the measurement panel 20 is often used outdoors, the measurement panel 20 is formed of a material that is not easily broken or deformed by the outdoor environment. The measurement panel 20 is typically a high-strength and high-durability panel obtained by firing a ceramic coating on a stainless steel panel. Grid lines 24 and 25 are drawn and burned before firing. In addition, the measurement panel 20 may be formed of, for example, pottery, porcelain, jar, or metal.

  FIG. 2B is a diagram illustrating a state in which two measurement panels are fixed on both sides of a crack generated on the inner wall of the tunnel. Two measurement panels 20 are fixed to both sides of the progressive crack 7 generated on the inner wall 5 of the tunnel, for example, using anchor bolts. For convenience of explanation, one of the two measurement panels 20 is a first measurement panel 20-1, and the other is a second measurement panel 20-2. The installation positions of the measurement panels 20-1 and 20-2 are preferably juxtaposed at intervals of several millimeters with the crack 7 interposed in consideration of shrinkage of the crack.

  As the crack 7 progresses, the relative positions of these measurement panels 20-1 and 20-2 change. In the present embodiment, the behavior of the crack is grasped by replacing it with a change in the relative position of the measurement panels 20-1 and 20-2.

  FIG. 3 is a diagram for explaining four elements obtained from calculation points and calculation results of two measurement panels. In the present embodiment, the relative position changes in the direction of the grid line 25 of any one measurement panel (20-2 in FIG. 3) in the X-axis direction, the direction in which the grid line 24 runs is the Y-axis direction, -The direction perpendicular to the Y plane (that is, the direction perpendicular to the surface of the measurement panel 20-2) is taken as the Z-axis direction.

  Calculation points 20a and 20b (indicated by ● in the figure) are respectively determined on the measurement panels 20-1 and 20-2, and the following four elements are obtained by calculation.

x: X-axis direction distance between calculation points 20a, 20b y: Y-axis direction distance between calculation points 20a, 20b z: Z-axis direction distance between calculation points 20a, 20b r: Linear distance between calculation points 20a, 20b Using these four elements, the relative three-dimensional displacement amount between the calculation points 20a and 20b (ie, the difference between the past measurement data (eg, initial measurement data, previous measurement data, etc.) and the current measurement data (ie, The actual behavior of cracks).

(Camera and shooting method)
As the digital camera 30, a commercially available camera can be used. The digital camera 30 preferably has 3 million or more effective recording pixels.

  Regarding the photographing method, in Patent Document 1, a set of two measurement panels is photographed from the front, and a grid drawn on the measurement panel is image-processed to calculate the distance between the measurement panels. It was. That is, the X-axis direction distance x and the Y-axis direction distance y between the calculation points 20a and 20b described with reference to FIG. 3 are obtained by calculation.

  In the present embodiment, in order to further determine the Z-axis direction distance z, the measurement panel 20 is photographed at a predetermined angle from the right and left directions. It has been found that the photographing angle is preferably about 15 degrees through trial experiments. For this reason, the following templates are prepared so that even if the user is unfamiliar with shooting, the shooting can be easily performed from a direction of about 15 degrees.

  The upper part of FIG. 4A shows a situation in which the measurement panels 20-1 and 20-2 are photographed with the photographing angle α by the camera 30. When viewed from the camera 30, the measurement panel 20-2 is located closer to the measurement panel 20-1. The lower row is the captured image 31. Due to the difference in perspective from the camera 30, the measurement panel image 20-1v in the image is smaller than the measurement panel image 20-2v. The angle of the inclined line 32 connecting the lower sides of the measurement panel images 20-1v and 20-2v with respect to the horizontal line is a function of the upper shooting angle α.

  FIG. 4B is a diagram illustrating a template 34 formed of a transparent member such as acrylic and disposed on the measurement panels 20-1 and 20-2 at the time of photographing. In the template 34, an inclination guide line 33-R that coincides with the inclination line 32 (see FIG. 4A) when the image is taken in advance from the imaging angle 15 degrees in the right direction toward the measurement panels 20-1 and 20-2. It is drawn. Similarly, an inclined guide line 33-L is drawn that coincides with the inclined line 32 when the image is taken from the left photographing angle of 15 degrees. The left-right direction region of the template 34 is from the right end portion 34R to the left end portion 34L.

  FIG. 4C is a diagram illustrating a work flow at the time of shooting in the field.

  In step S40, the digital camera 30 is prepared.

  In step S41, the template 34 is set on the measurement panels 20-1 and 20-2.

  In step S42, the camera 30 is positioned in front of the measurement panels 20-1 and 20-2, and the left and right ends 34R and 34L (see FIG. 4B) of the template 34 are aligned with the left and right frame lines of the imaging frame 36. Adjust the camera distance from the measurement panel. This is because the measurement panels 20-1 and 20-2 are photographed to the full size of the photographing frame 36. The shooting frame 36 is a frame of a liquid crystal panel for displaying a shot image provided in a digital camera, a frame of a camera finder, or the like.

  In step S43, as shown in the upper part of FIG. 4A, in order to obtain an image from the right direction, the camera 30 is moved to the + X axis until the tilt line 32 of the photographing frame 36 matches the tilt guide line 33-R of the template 34. Move in the direction and position. By this positioning, an angle of view of about 15 degrees (shooting angle α in FIG. 4A) is obtained.

  In step S44, the measurement panel is photographed from the right direction in this state. It is preferable to photograph 5 or more images.

  In step S45, in order to obtain an image from the left direction, the camera 30 is moved and positioned in the −X axis direction until the inclined line 32 of the photographing frame 36 matches the inclined guide line 33-L of the template 34. Similarly, an angle of view of about 15 degrees (shooting angle α in FIG. 4A) is obtained.

  In step S46, the measurement panel is photographed from the left in this state. It is preferable to photograph 5 or more images.

  It should be noted that step S43 and step S45 may be interchanged to reverse the shooting order, and shooting may be performed first from the left and then from the right.

  In this photographing method, as can be seen from FIG. 4A, the camera 30 is moved in the ± X-axis direction in the XZ plane to minimize the movement in the ± Y-axis direction. That is, in the right and left images, the variation is in the two-dimensional XZ plane in the three-dimensional XYZ. Alternatively, the camera 30 may be moved in the ± Y axis direction within the YZ plane to minimize movement in the X axis direction.

(Data processing apparatus and image processing method)
Please refer to FIG. A commercially available personal computer can be used as the data processing device 40. The OS of the data processing device 40 is preferably, for example, Windows XP, Vista or Windows 7, Intel Core 2 Duo or more as the CPU, and 2 GB or more as the main memory.

  As shown in FIG. 1, the data processing device 40 includes a monitor 50, an HDD 60 that accumulates image data, relative three-dimensional data between measurement panels obtained by arithmetic processing, and the like, and forms a database. And an optical disk drive 70 for driving a CD, a DVD or the like on which image processing software “crack ruler digital image simple calculation / management system (3D)” is recorded.

  FIG. 5 is a schematic flow of a processing method of the image processing software “crack ruler digital image simple calculation / management system (3D)”.

  First, the measurement data and the displacement amount will be described. FIG. 6 shows, as an example, the grid line intersections R1, R2, R3, R4 of one measurement panel (20-1) and the grid line intersection L1 corresponding to the other measurement panel (20-2). , L2, L3, and L4. These intersections become calculation points. Since these are image data, () is added to the reference symbol for display.

  As measurement data, the X-axis direction distance x1, the Y-axis direction distance y1, and the Z-axis direction distance z1 between the calculation points R1 and L1 are obtained by calculation. Similarly, distances x2, y2, and z2 between the calculation points R2 and L2 are obtained. Similarly, distances xn, yn, zn between the calculation points Rn and Ln (n = 1, 2, 3,...) Are obtained.

  Next, the numerical values of the X-axis direction distances x1, x2,..., Xn are different as the displacement amount, but when the measurement is performed a plurality of times, each of the past measurement values (first measurement value, previous measurement value, etc.). The difference (displacement amount) should be the same. Therefore, the average value of the displacement amounts (Δx1, Δx2,..., Δxn) is taken to increase the measurement accuracy of the X-axis direction displacement amount Δx. {Δx = (Δx1 + Δx2 +... + Δxn) / n}. The same applies to the Y-axis direction displacement amount Δy, the Z-axis direction displacement amount Δz, and the linear distance displacement amount Δr.

  In step S50, the measurement panels 20-1 and 20-2 are respectively photographed by the digital camera 30 from the right and left directions. Image data output from a normal digital camera is in the JPEG format in which high-resolution data is compressed, and cannot be processed as it is.

  In step 51, the JPEG data is converted into the BMP format and further converted into binary data “1” and “0”.

  In step S52, lens distortion correction is performed. Due to the distortion characteristics of the optical lens of the digital camera 30, the captured image is distorted. This distortion correction is performed.

  In step S53, an accurate linear equation of the vertical and horizontal grid lines 24 and 25 (see FIG. 2A) displayed on the measurement panel 20 is obtained from the binarized image data using the Hough transform (Hough transform). To expand into the virtual space.

  The Hough transform itself is a known feature extraction method used in digital image processing. Briefly, noise is present on line segment data captured by a digital camera (in this case, binarized data of grid lines of a set of dots scattered almost linearly). In computer processing, a linear equation representing this cannot be uniquely determined from line segment data with noise.

  For this reason, the Hough transform is used. In general, a straight line can be represented by ρ = x cos θ + ysin θ (ρ and θ are unknown parameters). In the computer, (ρ, θ) of this linear equation is sequentially changed to determine (ρ, θ) when the dot data of the line segment photographed by the digital camera is the highest. The resulting linear equation ρ = x cos θ + ysin θ (ρ and θ are known at this time) is a straight line that runs on the data of the line segment photographed by the digital camera. In other words, the linear equation accurately represents the grid line.

  In step S54, the position of the intersection of the grid lines is obtained from the exact linear equation of the vertical and horizontal grid lines 24 and 25. The intersections of the grid lines are used as the calculation points 20a and 20b (●) described with reference to FIGS.

  In step S55, X-axis direction distances xR and xL and Y-axis direction movement amounts yR and yL between the two calculation points viewed from the right and left directions are calculated.

  The X-axis direction distances xR and xL and the Y-axis direction distances yR and yL between the calculation points R1 and L1 will be described. FIG. 7A shows the situation at the time of photographing with the camera 30 facing from the right direction photographing angle α direction in the upper part, and the lower part shows the photographed image at that time. The measurement panels 20-1 and 20-2 are 20-2v larger than 20-1v due to the distance from the camera 30. Although not shown, when the camera 30 is pointed from the left shooting angle α direction, the image is 20-2v larger than 20-1v.

  Furthermore, please refer to FIG. FIG. 8 shows the measurement panels 20-1 and 20-2 in the upper part, and shows images obtained by photographing them from the right direction and the left direction in the lower part, respectively. Please be aware that it is exaggerated for the sake of clarity. The calculation points of the measurement panels 20-1 and 20-2 are displayed as black circles (●). The X-axis direction distance x1 between the calculation points is photographed at xR from the right direction and at xL from the left direction.

  In the measurement panels 20-1 and 20-2, the grid lines 24 and 25 form a plurality of 10 mm squares in the X-axis direction and the Y-axis direction. In the image data, the square formed by the grid lines is deformed according to the distance between the camera and the measurement panel. Using this, the X-axis direction movement amounts xR and xL and the Y-axis direction movement amounts yR and yL viewed from the right and left directions are calculated by proportional calculation. The same calculation is performed between the other calculation points Rn and Ln.

  In step S56, the frame shape of the display area 27 of the measurement panel is used to perform angle correction for restoring the distorted panel frame to a square, and the shooting angles αR and αL from the right and left directions and the focal length of the camera are corrected. F is calculated. The focal length F is the distance from the camera lens center to the imaging plane. In this correction, the square 26 formed by the grid lines 24 and 25 or this set may be used instead of the frame of the display area 27.

  Referring to FIG. 7 again, FIG. 7A shows the situation at the time of photographing with the camera 30 facing from the direction of the photographing angle α in the upper part, and the lower part shows the photographed image at that time. FIG. 7B shows a case where angle correction for restoring the distorted panel frame of FIG. 7A to a square, in other words, angle correction for changing the shooting angle of the captured image from α to zero is performed. By this angle correction, the photographing angle αR from the right direction, αL from the left direction, and the focal length F are obtained by calculation.

  In step S57, the shooting angles αR and αL from the right and left directions, the distances xR and xL between the calculation points of the measurement panel obtained in step S55, and the focal length F, the X-axis direction between the calculation points R1 and L1. The distance x1 and the Z-axis direction distance z1 are obtained by calculation. As the Y-axis direction distance y1, the difference between yR and yL obtained in step S55 is very small, so an average value is adopted. The distances between the other calculation points Rn and Ln are calculated in the same manner.

  FIG. 8 shows a diagram in which the measurement panels 20-1 and 20-2 are displaced in the Z-axis direction in the upper stage, and shows images taken from the right and left directions in the lower stage, respectively.

  From the distances xR and xL between the calculation points, the shooting angles αR and αL, and the focal length F, the X-axis direction distance x1 and the Z-axis direction distance z1 are obtained by calculation.

  As can be seen from FIG. 8, the Y-axis direction distance y1 between the calculation points is not taken into consideration. In general, in three-dimensional calculation using data of a plurality of photographs, displacement data x, y, and z in the XYZ axis directions are processed. However, in the present embodiment, as described with reference to FIG. 4C, the camera 30 is moved in the XZ plane and is not moved in the Y-axis direction to suppress the change in the Y-axis direction distance. Yes. Thus, when calculating the Z-axis direction distance z, it can be calculated as two-dimensional data in the XZ plane, the parameters can be reduced, and the Z-axis direction distance z can be calculated by relatively simple calculation. You can ask. Furthermore, the average value of the Y-axis direction distances yR and yL obtained in step S55 can be used as y1. Similarly, when the camera 30 is not moved in the X-axis direction, the X-axis direction distance x between the calculation points need not be taken into account in order to calculate the Z-axis direction distance z. The distances between the other calculation points Rn and Ln are calculated in the same manner.

In step S58, a linear distance r between the calculation points is obtained. The linear distance between the calculation points R1 and L1 is r1 = (x1 ² + y1 ² + z1 ² ) ^0.5 . Similarly, the linear distance between the other calculation points Rn and Ln is rn = (xn ² + yn ² + zn ² ) ^0.5 .

  Using these data, various processes can be performed. For example, the amount of displacement described with reference to FIG. For example, by making the measurement frequency relatively dense and comparing each measurement data with the most recent measurement data, not only displacement in one direction but also complicated behavior in three-dimensional space (time-dependent in each XYZ axis direction) Change behavior).

  For example, these data are classified by the bar code 22 displayed on the measurement panel 20, and changes over time are immediately displayed on the monitor 50 or output by a printer (not shown).

(Study on errors)
A three-dimensional displacement measurement system 1 for a structure according to the present embodiment was prototyped and the measurement accuracy was examined. The% FS (full scale) error relative to the distance between calculation points was determined. As a result of trial manufacture, the max. For 1.8% F and Y-axis direction movement amount y, max. For 1.8% FS and Z-axis direction movement amount z, max. It was 16% FS.

(Features, advantages, effects, etc. of this system)
This system has the following features.

  (1) As a component of the system, any special equipment, dedicated equipment, etc. can be used, and any of them can be configured with commercially available equipment. Accordingly, the cost can be kept relatively low.

  (2) The objects to be measured are not limited to civil engineering structures such as tunnels, but also include bridges and other structures, rocks where rocks are expected to collapse, and volcanoes such as active volcanoes.

  (3) Since the amount of movement z in the Z-axis direction is measured, the change in the Y-axis direction is suppressed, and the arithmetic processing is simplified, thereby enabling fast image processing / arithmetic processing.

  (4) It became possible to grasp the spatial behavior between two points of the measured object with numerical data.

  (5) When the measurer goes to a place where the object to be measured is located far away or in the back, it is possible to perform the measurement only by bringing a commercially available digital camera and, if necessary, a template.

[Summary]
The structure three-dimensional displacement measurement system using the digital camera according to the present embodiment has been described above, but these are examples and do not limit the scope of the present invention. Additions, deletions, changes, improvements, and the like that can be easily made by those skilled in the art with respect to the present embodiment are within the scope of the present invention. The technical scope of the present invention is defined based on the description of the attached claims.

  1: three-dimensional displacement measurement system, 5: inner wall of tunnel, 7: crack, crack, progressive crack, 15: shooting angle, 20: measurement panel, 20a, 20b: calculation point, 21: anchor hole, 22: barcode 23: Caliper measurement hole, 24: Grid line, 26: Square, 27: Display area, 30: Digital camera, 31: Photographed image, 31L: Image from the left direction, 31R: Image from the right direction, 32: Inclined line 33: Inclined guide line, 34: Template, 34L: Left end, 34R: Right end, 34R: Left and right ends, 36: Shooting frame, 40: Data processing device, computer, 50: Monitor, 70: Optical disc drive,

Claims (13)

Two measuring panels, each installed at a relatively displaced location on the surface of the object to be measured, each displaying a grid line;
A digital camera for photographing the measurement panel from two directions;
A data processing device for processing image data of the digital camera,
The data processing device includes:
Means for image processing the image data of the digital camera based on the grid lines;
Means for correcting the angle of the image data to calculate a shooting angle and a focal length;
If the X-axis direction and the Y-axis direction are defined on the basis of the grid lines, and if the direction perpendicular to the XY plane is defined as the Z-axis direction, the image-processed image data, angle processing data, and focal length data are used. the X-axis direction distance between the two measuring panel, Y-axis direction distance, have a means for calculating the Z axis direction distance and linear distance,
The means for calculating the X-axis direction distance, the Y-axis direction distance, the Z-axis direction distance, and the linear distance is calculated between the calculation points R1 and L1 from the distances xR and xL and the focal length F between the calculation points of the measurement panel. The X-axis direction distance x1 and the Z-axis direction distance z1 are obtained by calculation, the average value of the Y-axis direction distances yR and yL is used as y1, and the linear distance between the calculation points R1 and L1 is r1 = (x1 ² + Y1 ² + z1 ² ) A three-dimensional displacement measurement system using a digital camera, obtained as ^0.5 . In the three-dimensional displacement measuring system using the digital camera according to claim 1,
The digital camera has an effective recording pixel number of at least 3 million pixels or more. In the three-dimensional displacement measuring system using the digital camera according to claim 1,
The calculation point is an intersection of the grid lines. In the three-dimensional displacement measuring system using the digital camera according to claim 1,
The measurement panel further includes a bar code displayed, and data is processed and databased based on the bar code. In the three-dimensional displacement measuring system using the digital camera according to claim 1,
Furthermore, a template formed of a transparent member is provided to cover the two measurement panels at the time of shooting, and an inclined guide line is drawn on the template, and the shooting frame of the digital camera is tilted at the time of shooting. A system that allows shooting from a desired direction by matching the guide line. In the three-dimensional displacement measuring system using the digital camera according to claim 1,
The system to be measured includes a structure, a civil structure, a rock, a dangerous slope, and an active volcano. In the three-dimensional displacement measuring system using the digital camera according to claim 1,
The two-direction shooting is a system in which the digital camera is moved in the XZ plane without moving in the Y-axis direction. In the three-dimensional displacement measuring system using the digital camera according to claim 1,
In the imaging from the two directions, the digital camera is moved in the YZ plane without moving in the X-axis direction. In a three-dimensional displacement measurement method using a digital camera using two measurement panels, each of which is installed at a relatively displaced location on the surface of the object to be measured, each displaying a grid line.
Photographed from two directions with a digital camera, two measurement panels, each displaying grid lines, installed at locations relatively displaced on the surface of the object to be measured,
The image data from the digital camera is image-processed based on the grid lines, further angle-corrected to calculate a shooting angle and a focal length, and an X-axis direction distance and a Y-axis direction distance between the two measurement panels. , A method for calculating a Z-axis direction distance and a straight-line distance,
The method of calculating the X-axis direction distance, the Y-axis direction distance, the Z-axis direction distance, and the linear distance is based on the distances xR and xL between the calculation points of the measurement panel and the focal length F between the calculation points R1 and L1. The X-axis direction distance x1 and the Z-axis direction distance z1 are obtained by calculation, the average value of the Y-axis direction distances yR and yL is used as y1, and the linear distance between the calculation points R1 and L1 is r1 = (x1 ² + Y1 ² + z1 ² ) A three-dimensional displacement measurement method obtained as ^0.5 . In the three-dimensional displacement measuring method using the digital camera according to claim 9,
The imaging from the two directions is a three-dimensional displacement measurement method in which the digital camera is moved in the XZ plane without moving in the Y-axis direction. In the three-dimensional displacement measuring method using the digital camera according to claim 9,
The imaging from the two directions is a three-dimensional displacement measurement method in which the digital camera is moved in the YZ plane without moving in the X-axis direction. On the computer,
The computer program for performing the three-dimensional displacement measuring method using the digital camera as described in any one of Claims 9-11.   A computer-readable recording medium on which the computer program according to claim 12 is recorded.