Standard scale, standard scale set, image analysis device, and image analysis method

Abstract

To provide a reference scale that is excellent in handleability such as installation or transportation, realizing a highly accurate measurement.SOLUTION: A reference scale 1 comprises: a rod-shaped reference scale body 2; at least three first recognition parts 3, which are displayed at least on both end parts 21 of the reference scale body 2 and on the longitudinal central part of the reference scale body 2, for indicating the length of the reference scale body 2; and second recognition parts 4, which are aligned on a straight line through at least the three first recognition parts 3, for discerning the reference scale body 2 on which the first recognition parts 3 are displayed. The first recognition part 3 is also displayed on a center part 22 of the reference scale body 2 in the longitudinal direction. The first recognition part 3 and the second recognition part 4 are configured to have their own circle outlines.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a scale, a scale set, an image analysis device, and an image analysis method. [Background technology]

[0002] In construction management, it is desirable to check whether the size and location of installed structures are consistent with the construction drawings. However, apart from during construction, it is inefficient to measure the position and dimensions of individual structures using a tape measure or surveying equipment for inspection and status assessment. To address this issue, a technique described in Patent Document 1 is known.

[0003] Claim 1 of Patent Document 1 describes a photogrammetric target measuring device comprising: a fixing means for fixing a photogrammetric target used as a reference scale for photogrammetry at a predetermined position; a photographing means for photographing at least three reference point members provided on the photogrammetric target and positioned on the same plane; an image analyzing means for performing image analysis on the photographed image obtained by the photographing means to determine the relative coordinates of the center of gravity of the reference point members in the photographed image; and a calculation means for determining the distance between the reference point members based on the position of the photographing means and the coordinates of the center of gravity determined by the image analyzing means. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-121362 Summary of the Invention [Problem to be solved by the invention]

[0005] The photogrammetric target measuring device described in Patent Document 1 has an L-shape (see FIG. 4, etc.), which may make it difficult for users to transport the device to a construction site or other such work site, and may limit the location where the device can be installed at the work site. The problem to be solved by the present disclosure is to provide a measuring scale, a measuring scale set, an image analysis device, and an image analysis method that realize highly accurate measurements and are easy to handle during installation, transportation, etc. [Means for solving the problem]

[0006] The scale of the present disclosure comprises a rod-shaped scale body, at least three first identification portions that are displayed at least at both ends of the scale body and at the center in the longitudinal direction of the scale body and indicate the length of the scale body, and a second identification portion that is arranged on a line passing through the at least three first identification portions and that identifies the scale body that displays the first identification portions. The first recognition portion is larger than the second recognition portion, and has a rod shape that does not bend when placed at a construction site. Other solutions are described later in the detailed description of the invention. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a standard scale, a standard scale set, an image analysis device, and an image analysis method that realize highly accurate measurements and are easy to handle during installation, transportation, etc. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a scale. [Figure 2] FIG. 10 is a diagram illustrating the length of a standard scale. [Figure 3] This shows the XL axis aligned along the scale and the YL axis aligned perpendicular to the XL axis in the same plane as the scale. [Figure 4] FIG. 10 is a diagram for explaining a comparison of the first recognition portion and the second recognition portion displayed on a plurality of scales, and shows a set of scales. [Figure 5] 10 is a diagram illustrating a first recognition portion and a second recognition portion on a sheet attached to an end portion. FIG. [Figure 6] 10 is a diagram illustrating a first recognition portion and a second recognition portion on a sheet attached to the center portion. FIG. [Figure 7] FIG. 1 is a block diagram showing an image analysis device. [Figure 8]FIG. 1 is a diagram showing a plurality of scales placed near a structure at a construction site. [Figure 9] FIG. 1 is a diagram illustrating the relationship between a scale coordinate system, an object coordinate system, and a photograph coordinate system. [Figure 10] FIG. 1 is a diagram illustrating the synthesis of two orthoimages. [Figure 11] 1 is a flowchart illustrating an image analysis method. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, modes for carrying out the present disclosure (hereinafter referred to as "embodiments") will be described with reference to the drawings. In the following description of one embodiment, other embodiments applicable to the one embodiment will also be described as appropriate. The present disclosure is not limited to the one embodiment below, and different embodiments can be combined with each other or modified as desired without significantly impairing the effects of the present disclosure. Furthermore, the same components will be given the same reference numerals, and redundant descriptions will be omitted. Furthermore, components having the same functions will be given the same names. The contents shown are merely schematic, and for convenience of illustration, changes may be made from the actual configuration within the scope of not significantly impairing the effects of the present disclosure, and some components may be omitted or modified between drawings.

[0010] FIG. 1 is a schematic diagram of a scale 1. The scale 1 is used to generate orthoimages by analyzing images obtained by imaging. The scale 1 comprises a scale body 2, a first recognition section 3 (main target code), and a second recognition section 4 (secondary target code). As will be described in detail later, the first recognition section 3 is composed of a black circular band, and the second recognition section 4 is composed of a black or white circle. Note that the "white circle" does not actually represent the outline of a circle displayed on a white sheet 5; in the illustrated example, a virtual circle is displayed on the sheet 5. In the illustrated example, the white sheet 5 displaying the first recognition section 3 and the second recognition section 4 is affixed to the scale body 2, for example, via adhesive.

[0011] The scale body 2 is equipped with dimensional markings such as scales (not shown) and is installed at a construction site, for example, a building site. By capturing an image including the scale body 2, the dimensions of the structure 30 (Figure 8) can be determined from the image 203 (Figure 9, photograph, etc.) obtained by capturing the image. The scale body 2 is rod-shaped. There are no specific limitations on the shape of the rod, as long as it has a "rod-like shape" when viewed externally, and it can have any cross-sectional shape, such as a circle or rectangle, when viewed in a cross section perpendicular to the longitudinal direction. There are also no particular limitations on the dimensions. The scale body 2 in this embodiment is made of a strip of plate extending in one direction.

[0012] The first identification elements 3 are displayed at least at both ends 21 of the scale body 2 and at the longitudinal center 22 of the scale body 2, and indicate the length of the scale body 2; at least three first identification elements 3 are provided. The dimensions of the scale body 2 are given on the image 203 (Figure 9) based on the spacing between the three first identification elements 3. The "ends 21" do not necessarily have to be at the exact ends of the scale body 2; they may be located at a position where the spacing between the first identification elements 3 can be considered to be roughly the dimensions of the scale body 2.

[0013] The first recognition unit 3 is configured with a circular outline. This allows the first recognition unit 3 to be recognized in the same way no matter in which direction the first recognition unit 3 is distorted when the scale 1 including the first recognition unit 3 is imaged. This makes it easier to determine the distance based on the first recognition unit 3. In the illustrated example, the first recognition unit 3 has a shape with an inner circle and an outer circle painted black, that is, a black circular band with a white center (the base color of the sheet 5). Furthermore, the color of the first recognition unit 3 does not have to be limited to black as illustrated.

[0014] As described above, the first recognition portion 3 is also displayed at the longitudinal center portion 22 of the scale body 2. This allows the distance from each end portion 21 to the center portion 22 to be determined on the image 203 (FIG. 9).

[0015] Figure 2 is a diagram illustrating the length of the scale 1. The center-to-center distance between the first recognition elements 3 located at both end portions 21 is L1, which roughly matches the dimensions of the scale 1 and the scale body 2. The center-to-center distance between the first recognition element 3 located at the central portion 22 and the first recognition elements 3 located at one and the other end portions 21 is L2. L2 is half of L1. The distance between one end 24 and the other end 24 of the scale body 2 is L1 + 2 × L3 (Figure 5).

[0016] Figure 3 shows the X axis along the scale 1. L axis and scale 1 in the same plane as X L Y aligned perpendicular to the axis L The center of the first recognition unit 3 disposed at the end 21 is set as the origin O, and the X axis is L axis and Y L The center of the first recognition unit 3 is the X axis. L The points are P1, P2, and P3 on the axis, and point P1 coincides with the origin O.

[0017] The second recognition section 4 is for identifying the scale body 2 on which the first recognition section 3 is displayed, and is a straight line X passing through at least three first recognition sections 3. L The first recognition unit 3 and the second recognition unit 4 are arranged on the X axis. L By arranging the scale on the axis, it is possible to determine the scale coordinate system for the scale 1, as will be described in detail later. Furthermore, at least two scales 1 are used in combination. Therefore, in order to identify the scale 1 on an image 203 (FIG. 9) that includes multiple scales 1, the second recognition unit 4 is used.

[0018] FIG. 4 is a diagram illustrating a scale standard set 10, comparing the first and second measurement units 3 and 4 displayed on multiple scale standards 1. In the illustrated example, the scale standard set 10 includes four scale standards 1a, 1b, 1c, and 1d. However, the scale standard set 10 may include at least two scale standards 1, and may include two, three, or even five or more. For ease of illustration, only the first measurement unit 3 and the second measurement unit 4 provided on each of the scale standards 1a, 1b, 1c, and 1d are shown. For ease of illustration, reference numerals other than those associated with the scale standards 1b, 1c, and 1d are omitted. In the following description, the scale standards 1a, 1b, 1c, and 1d may be referred to as the first scale standard 1, the second scale standard 1, the third scale standard 1, and the fourth scale standard 1, respectively.

[0019] Each of the scales 1a, 1b, 1c, and 1d has a scale body 2 of the same length. Therefore, the first recognition section 3 is displayed in the same position. On the other hand, the second recognition section 4 is displayed in the same place, but has a different shape for each of the scales 1a, 1b, 1c, and 1d.

[0020] That is, the second recognition section 4 includes a plurality of unit recognition sections 4a that differ in at least one aspect of color or shape, and has a unique aspect for each scale standard 1. In other words, the second recognition section 4 in each scale standard 1 that makes up the scale standard set 10 includes a plurality of unit recognition sections 4a that differ in at least one aspect of color or shape, and has said aspect unique for each scale standard 1. In the example shown, the shapes are the same but the colors are different.

[0021] Specifically, scale standard 1a includes seven unit recognition sections 4a, which are arranged from left to right on the paper as follows: black circle, white circle, white circle, black circle, white circle, black circle, white circle, black circle. Scale standard 1b has unit recognition sections 4a (reference numbers omitted from scale standard 1b) which are arranged from left to right on the paper as follows: black circle, black circle, white circle, black circle, black circle, white circle, black circle. Scale standard 1c has unit recognition sections 4a (reference numbers omitted from scale standard 1c) which are arranged from left to right on the paper as follows: black circle, white circle, black circle, white circle, black circle, black circle, black circle. Scale standard 1d has unit recognition sections 4a (reference numbers omitted from scale standard 1d) which are arranged from left to right on the paper as follows: black circle, black circle, black circle, black circle, black circle, black circle, black circle. In this way, the second recognition unit 4 has a different configuration for each of the scale standards 1a, 1b, 1c, and 1d, which makes it possible to identify the scale standards 1a, 1b, 1c, and 1d on the image 203 (FIG. 9).

[0022] The second recognition unit 4 is configured with a circular outline, similar to the first recognition unit 3. This allows the second recognition unit 4 to be recognized in the same way no matter in what direction the second recognition unit 4 is distorted when the scale 1 including the second recognition unit 4 is imaged. This makes it easier to recognize the second recognition unit 4. Furthermore, the color of the second recognition unit 4 does not need to be limited to black and white as shown in the figure.

[0023] The second recognition unit 4 further includes a third recognition unit 4b for error correction during recognition of the second recognition unit 4. By including the third recognition unit 4b, even if the second recognition unit 4 cannot be recognized, the scales 1a, 1b, 1c, and 1d can be recognized through error correction. In particular, at construction sites and other work sites, recognition errors can occur when parts of the first recognition unit 3 and second recognition unit 4 are hidden by the object being imaged, or due to light reflection or exposure caused by the imaging direction or imaging conditions, forcing the image to be retaken. However, by including the third recognition unit 4b, such situations can be prevented.

[0024] In the illustrated example, the unit recognition section 4a surrounded by dashed frame 44 has the same form as the unit recognition section 4a surrounded by dashed frame 43. Furthermore, the unit recognition section 4a surrounded by dashed frame 45 has the same form as the unit recognition section 4a surrounded by dashed frame 46. For example, even if the unit recognition sections 4a surrounded by dashed frames 44 and 45 cannot be recognized due to lighting conditions, the third recognition section 4b (unit recognition section 4a) surrounded by dashed frames 43 and 45 can be used as a clue to recognize the scales 1a, 1b, 1c, and 1d. Furthermore, the unit recognition sections 4a not surrounded by dashed frames 44 and 45 are common to all scales 1, so their reference numerals are omitted from the illustration, but they can be easily complemented by using them as the third recognition section 4b.

[0025] Figure 5 is a diagram illustrating the first identification portion 3 and the second identification portion 4 on the sheet 5 attached to the end portion 21. The diameter of the first identification portion 3 is D1, and the diameter of the second identification portion 4 is D2. The sheet 5 is attached to the scale body 2 so that the edge 51 of the sheet 5 overlaps the edge 24 (Figure 2) of the scale body 2. The distance between the edge 51 and the center of the first identification portion 3 is L3. L3 is, for example, the same length as D1. The distance between the center of the first identification portion 3 and the center of the adjacent second identification portion 4 is L4. The center-to-center distance between adjacent second identification portions 4 is L5.

[0026] As will be described in detail later, when recognizing the first recognition unit 3 and the second recognition unit 4 on the image 203 (FIG. 9), the first recognition unit 3 is recognized first, and then the second recognition unit 4 is recognized based on the position and size (e.g., diameter) of the first recognition unit 3. For this reason, from the viewpoint of ease of recognition, the first recognition unit 3 is configured to be larger than the second recognition unit 4. Furthermore, it is preferable that the distance between the first recognition unit 3 and the second recognition unit 4 and the distance between adjacent second recognition units 4 are somewhat wide to prevent the first recognition unit 3 and the second recognition unit 4, or the second recognition units 4, from being recognized as overlapping on the image 203. Therefore, L4 and L5 are, for example, approximately the same as D2.

[0027] FIG. 6 is a diagram illustrating the first recognition section 3 and the second recognition section 4 on the sheet 5 attached to the central section 22. Recognition of the scale 1 is performed, for example, based on the second recognition section 4 in the central section 22. The dimensions of the first recognition section 3 and the second recognition section 4, the distance between adjacent first recognition sections 3 and second recognition sections 4, and the distance between adjacent second recognition sections 4 are the same as those in the example shown in FIG. 5. In FIG. 6, second recognition sections 4 are arranged on both the left and right of the first recognition section 3, with a center-to-center distance L4.

[0028] The above-mentioned scale 1 can also be used to generate orthoimages by processing images 203 (Fig. 9) obtained by capturing images at a construction site where the scale 1 is placed. By using the scale 1 for such purposes, an orthoimage 201 (Fig. 10) of the construction site can be generated through image analysis. In particular, the scale 1 is configured in a rod shape with no bends, making it easy to handle during installation, transportation, etc. This simplifies the work required to generate orthoimages. Furthermore, the use of the scale 1 enables highly accurate measurements to be achieved.

[0029] The image analysis device 100 and image analysis method for analyzing the image 203 including the scale 1 will be described with reference to FIG. 7 and subsequent figures.

[0030] 7 is a block diagram showing an image analyzing device 100. The image analyzing device 100 includes a target coordinate determining unit 101, an image generating unit 102, an image combining unit 103, and a display unit 104. Although none of these are shown, the image analyzing device 100 is configured to include, for example, a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), and the like. The image analyzing device 100 is realized when a predetermined control program stored in the ROM is loaded into the RAM and executed by the CPU.

[0031] The object coordinate determination unit 101 determines the object coordinate system based on the scale coordinate system and the photograph coordinate system. The scale coordinate system is a coordinate system based on the first recognition unit 3 on the scale 1. The photograph coordinate system is a coordinate system based on the first recognition unit 3 on the scale 1 in at least one image 203 (Figure 9) of the construction site, which includes at least two scales 1. The object coordinate system is a coordinate system based on a specified scale (e.g., scale 1a), which is one of the at least two scales 1 at the actual construction site.

[0032] Therefore, the object coordinate determination unit 101 determines the actual object coordinate system at the construction site based on a known scale coordinate system based on the design information of the scale 1 (the length of the scale 1, the display location of the first recognition unit 3, etc.) and the photographic coordinate system of the scale 1 in the image 203 obtained by imaging. This makes it possible to grasp the horizontal rotation angle and parallel movement distance of another scale 1 (for example, scale 1b) using one of the scales 1 (a specified scale) as a reference.

[0033] Figure 8 is a diagram showing multiple scales 1 placed near a structure 30 at a construction site. In the example shown, two scales 1 are placed, but it is sufficient to place at least two scales 1, and for example, four scales 1a, 1b, 1c, and 1d as shown in Figure 2 may be used.

[0034] At a construction site, for example, a manager places at least two measuring standards 1 near a structure 30 such as a sleeve. Of the measuring standards 1, measuring standard 1a (the above-mentioned specified measuring standard), which is the measuring standard 1 that serves as the basis for determining the target coordinate system, is placed on the X axis parallel to, for example, a center line (not shown). However, the remaining measuring standard 1 (measure standard 1b in the illustrated example) may be placed in any position and orientation as long as it is included in the same image 203 (Figure 9) as measuring standard 1a. In other words, measuring standard 1b may be placed, for example, parallel to the X axis, on the Y axis or parallel to the Y axis, or at an angle to at least one of the X axis or the Y axis.

[0035] The photograph coordinate system is determined, for example, as follows. First, for each of the multiple scales 1 in the image 203, which scale 1 is the corresponding scale is determined. Specifically, in the image 203, areas where there is a strong contrast between the white background and the black foreground are first detected as candidates for the first recognition unit 3. In this disclosure, the first recognition unit 3 has a circular outline and is usually photographed from an oblique angle, so it appears as an ellipse in the image 203. Therefore, in this disclosure, an elliptical one of the detected areas is selected. The first recognition unit 3 is also determined based on the relative size relationship between the inner white circle and the outer black circle (for example, the radius of the white circle is approximately half the radius of the black circle).

[0036] Based on the obtained diameter of the first recognition part 3 (D1 in FIG. 5), L4 and L4 + L5 on the image 203 are calculated, and the part located at that distance is extracted as the second recognition part 4. After extraction, second recognition parts 4 whose sizes, center-to-center distance, etc. differ from known information are rejected as erroneous detections. Based on the arrangement of the first recognition part 3 and second recognition part 4 detected in the above manner and the known arrangement pattern shown in FIG. 4, for example, it is determined which standard scale 1 in the image 203 corresponds to. Note that in this series of processes, the above-mentioned error correction is performed as appropriate using the third recognition part 4b (FIG. 4).

[0037] Figure 9 is a diagram explaining the relationship between the scale coordinate system, object coordinate system, and photograph coordinate system. The object coordinate determination unit 101 analyzes the position of the scale 1 on the image 203 to determine information used to generate the orthoimage 201 (Figure 10), such as the relative shooting position, shooting direction, and scale of the image 203. This determination can be performed by, for example, coordinate transformation and projection transformation, so each coordinate system will first be explained.

[0038] For each scale 1, a local coordinate system, scale coordinate system X L -Y L -Z Lis defined. The scale coordinate system is a common coordinate system for both scales 1a and 1b. Therefore, as long as the first recognition unit 3 is located in the same place, the scale coordinate system is the same regardless of the location of the scale 1. The scale coordinate system has the center of the first recognition unit 3 at one end 21 as the coordinate origin, the X axis pointing toward the other end 21, the Y axis perpendicular to the X axis and running in the same plane as the scale 1, and the Z axis pointing in the height direction. In the example shown, the first recognition unit 3 is displayed in three places: both end parts 21 and the central part 22. If the point numbers corresponding to the centers of the first recognition units 3 are P1, P2, and P3, the coordinates of P1 in the scale coordinate system are (0,0,0), P2 are (L2,0,0), and P3 are (L1,0,0) (see Figure 2 for both L1 and L2).

[0039] In contrast, the coordinate system defined as a unified coordinate system in real space is the object coordinate system XYZ. The object coordinate system is identical to the coordinates in the scale coordinate system of the above-mentioned specified scale 1a. For example, the points in the object coordinate system corresponding to points P1, P2, and P3 in the scale coordinate system are P11, P12, and P13, respectively. In this case, the object coordinate system has P1 on the first scale 1a (point P11 in the object coordinate system) as its coordinate origin, the direction extending from P11 to P13 as the X-axis, the axis perpendicular to this in the same plane as the scale 1 as the Y-axis, and the axis extending in the height direction as the Z-axis.

[0040] The coordinates of P11 in the target coordinate system on the scale 1a are (X 11 ,Y 11 ,Z 11 ), and the coordinate of P12 in the target coordinate system is (X 12 ,Y 12 ,Z 12 ), and the coordinates of P13 in the target coordinate system are (X 13 ,Y 13 ,Z 13 ) In addition, the coordinates of P21, P22, and P23 in the scale coordinate system of the scale 1b are the same as those of P11, P12, and P13 in the scale 1a. However, the coordinate of P21 in the target coordinate system is (X 21 ,Y 21 ,Z 21 ), and the coordinates of P22 in the target coordinate system are (X22 ,Y 22 ,Z 22 ), and the coordinates in the target coordinate system of P23 are (X 33 ,Y 33 ,Z 33 )

[0041] The object coordinate system is obtained by translating and rotating the scale coordinate system in the horizontal plane, and is therefore expressed by the following equation (1) which indicates an orthogonal transformation: Equation (1) (first relation) indicates the relationship between the object coordinate system and the scale coordinate system, and includes parameters which differ for each captured image 203.

[0042]

number

[0043] X Lj is the X coordinate in the scale coordinate system, and j is the number of the first recognition unit 3 on the same scale 1 (points P1, P2, and P3 are numbered 1, 2, and 3, respectively). For example, j is 1, 2, and 3 for the first recognition units 3 corresponding to points P1, P2, and P3, respectively. On the other hand, (Xij, Yij, Zij) are coordinates expressed in the target coordinate system, and i is the number of the scale 1. For example, i is 1 for scale 1a, and 2 for scale 1b. For scales 1c and onwards, i similarly increases by 1. (Xi0, Yi0, Zi0) is the amount of parallel movement of scale 1 expressed in the target coordinate system, with scale 1a as the reference, and corresponds to the coordinates of point P1 on each scale 1a expressed in the target coordinate system. Also, ω i is the angle of rotation in the horizontal plane, and represents the horizontal angle of rotation of the first scale 1a when the first scale 1a is used as the reference.

[0044] 9, a photographic coordinate system xyz is determined for each captured image 203. The photographic image system has the center of the image 203 as the coordinate origin, the x-axis in the left-right direction of the image 203, the y-axis in the up-down direction of the image 203, and the z-axis in the optical axis direction.

[0045] The photograph coordinate system and the object coordinate system have a projection relationship based on central projection. The relational expression is the following expression (2). Expression (2) (second relation) shows the relationship between the object coordinate system and the photograph coordinate system.

[0046]

number

[0047] r is the image number. If there is only one image, r is 1. If there are two or more images, r is 2 or more in any order. (x ijr ,y ijr ,-f) represents the coordinates in the photographic coordinate system, and λ ijr is the scale factor, κ r is the rotation angle around the optical axis (around the z-axis), φ r is the rotation angle around the x-axis, ρ r is the rotation angle around the y-axis, (X r0 ,Y r0 ,Z r0 ) is the photographing position of the image 203. It is assumed that the lens distortion of the image 203 has been corrected in advance by any method.

[0048] The object coordinate determination unit 101 simultaneously solves the following equation (3), which is obtained by substituting equation (1) into equation (2). Equation (3) (third relation) is a third relation that indicates the relationship between the photograph coordinate system, object coordinate system, and scale coordinate system, which is derived from equations (1) and (2).

[0049]

number

[0050] In this method, instead of solving the three-dimensional coordinates X, Y, Z in the target coordinate system of the first recognition unit 3, ωi, X i0 , Y i0 , Z i0In other words, in the present disclosure, equation (3) is used as the basic equation, so there is no need to give coordinates (X, Y, Z) for each individual first recognition unit 3. Therefore, the scale 1 can be positioned freely. As a specific solution method, a bundle adjustment method using a general nonlinear least squares method is applied. The only difference from a general bundle adjustment method is that the basic equation is equation (3), and there are no other major differences, so details will be omitted.

[0051] In this disclosure, the number of independent fundamental equations exceeds the number of unknowns to be solved. For example, assume that one scale 1 is captured in one image 203. In this case, equation (3) holds for three points P1, P2, and P3. If the scale factor λ is removed from equation (3), it essentially becomes two equations, so six equations can be established for one scale 1. On the other hand, if two scales 1 are placed as in this disclosure, 2 x 6 = 12 independent equations are created. In contrast, the unknowns to be solved are the orientation elements κ, φ, ρ, and X of the image 203. ro ,Y ro ,Z ro In addition to the six items above, the parallel movement of the second scale 1 (X 2o ,Y 2o ,Z 2o ) and horizontal rotation ω2, for a total of 10. Therefore, even in a single photograph, all unknowns can be solved by placing at least two scales 1. In fact, since there is a margin for two in the basic equation, it can be solved even if one point in the first recognition part 3 is missing.

[0052] As described above, the object coordinate determination unit 101 determines all unknowns (parameters) included in equation (3) for each scale 1. Then, the object coordinate determination unit 101 determines the object coordinate system based on the determined unknowns, equations (1), (2), and the photograph coordinate system. According to this determination method, the object coordinate system can be determined by using at least two scales 1.

[0053] In addition, as described above, all unknowns (parameters) are determined by the rotation angle ω of the standard scale 1b (target standard scale) from which the unknowns are determined relative to the standard scale 1a (predetermined standard scale) in the horizontal plane.i , and the parallel movement of the scale 1b relative to the scale 1a (X 2o ,Y 2o ,Z 2o ) By determining these, we can solve the above equation (3).

[0054] Then, the target coordinate determination unit 101 determines the unknowns by solving the equation (3) that is established for each scale 1 and each first recognition unit 3. In this way, the parameters in the equation (3) can be determined.

[0055] Returning to Fig. 7, the image generation unit 102 generates an orthoimage 201 (Fig. 10) corresponding to the captured image 203 (Fig. 9) based on the target coordinate system determined by the target coordinate determination unit 101 and the captured image 203. In the target coordinate system, the height Z can be set to the same height (Z = 0) as the first scale 1 (scale 1a), so this actually amounts to a conversion from two-dimensional coordinates (x, y) to (X, Y). By performing this for all pixels on the image 203 and then providing a resolution such as 1 mm = 1 pixel, the orthoimage 201 in the target coordinate system can be generated.

[0056] The image synthesis unit 103 synthesizes orthoimages 201 and 202 (FIG. 10) obtained from at least two images 203 and 204 (FIG. 10) of different regions, respectively, to create a single orthoimage 201 or 202 including each region. The image synthesis unit 103 can create a single orthoimage 205 (FIG. 10) that represents a wide range.

[0057] 10 is a diagram illustrating the synthesis of two orthoimages 201 and 202. The orthoimages 201 and 202 obtained from one image 203 and 204 are represented in a unified reference coordinate system based on the reference scale 1a. Therefore, the orthoimages 201 and 202 can be synthesized by capturing multiple images 203 and 204, converting each of the images 203 and 204 into the orthoimages 201 and 202, and then making the areas outside the ranges of each of the images 203 and 204 transparent (not projecting).

[0058] When a wide area is photographed using three or more scales 1, it is possible that scale 1a may not be visible. In such cases, equation (3) can be formulated and solved using another scale 1 (for example, scale 1 No. 2, 3, or 4) as the reference, and then equation (1) can be substituted from scale 1 No. 2, 3, or 4 calculated using another image (not shown) to scale 1, thereby converting it into equation (3) using scale 1 No. 1 as the reference. This creates a unified target coordinate system, allowing an orthogonal image (not shown) to be obtained in the same way.

[0059] Returning to Figure 7, the display unit 104 displays the generated orthoimage 201 (Figure 10) and the corresponding construction drawing at the construction site superimposed on the display device 105 (for example, a display). This makes it clear at a glance whether construction has been carried out according to the construction drawing, making construction management easy. The construction drawing can be input to the display unit 104, for example, via an input device (keyboard, mouse, inserting a USB memory into a USB terminal, etc.).

[0060] Fig. 11 is a flowchart showing an image analysis method. The image analysis method of the present disclosure can be performed using, for example, image analysis device 100 (Fig. 7). Therefore, Fig. 11 will be described with reference to Fig. 7 as appropriate. The image analysis method of the present disclosure includes the following steps S1 to S13.

[0061] First, as shown in FIG. 9, for example, the administrator places at least two scales 1 near the structure 30 (step S1). Of these, scale 1a is placed parallel to, for example, a street center line (not shown). Next, the administrator uses an imaging device (not shown), such as a camera, to capture images of the construction site that include at least two scales 1, thereby obtaining at least one image (hereinafter, images 203 and 204 (FIG. 10) are exemplified) (step S2, imaging step). The captured image is transferred to the image analyzing device 100 either manually by the administrator or automatically in response to an instruction from the image analyzing device 100 (step S3).

[0062] The object coordinate determination unit 101 of the image analysis device 100 corrects lens distortion of the transferred images 203 and 204 (step S4). The correction is performed by any method based on the physical properties of the lens (not shown) of the imaging device used. The object coordinate determination unit 101 detects candidates for the first recognition unit 3 and the second recognition unit 4, for example, based on brightness (step S5). Next, the object coordinate determination unit 101 eliminates any incorrectly detected candidates based on their shape and arrangement (step S6). The object coordinate determination unit 101 then recognizes the first recognition unit 3 and the second recognition unit 4 displayed on both end portions 21 and the central portion 22. At this time, the object coordinate determination unit 101 appropriately complements any second recognition unit 4 in which a recognition error occurred (step S8). Through steps S4 to S8, the object coordinate determination unit 101 determines the number of the scale 1 (if two scales 1 are used, the first scale 1a and the second scale 1b) (step S9).

[0063] The object coordinate determination unit 101 determines the object coordinate system of each standard scale 1 at the actual construction site based on the above-mentioned standard scale coordinate system and photograph coordinate system through image analysis (step S10, object coordinate determination step). The image generation unit 102 generates orthoimages 201, 202 (FIG. 10) corresponding to the images 203, 204 based on the object coordinate system determined in step S10 and the images 203, 204 (FIG. 10) (step S11, image generation step). The image synthesis unit 103 synthesizes at least two orthoimages 201, 202 generated for each image 203, 204 (step S12). Finally, the display unit 104 superimposes the orthoimage 205 (FIG. 10) obtained by synthesis and the construction drawing on the display device 105 (step S13).

[0064] According to the image analysis device 100 and image analysis method described above, orthoimages can be generated based on images 203, 204 in which the second and subsequent scales 1 are placed in any position. This makes it easy to generate the orthoimages 201, 202. Furthermore, because the second and subsequent scales 1 can be placed in any position, the degree of freedom in installation is improved, and the number of locations from which the orthoimages 201, 202 can be generated can be increased. Furthermore, the orthoimages 201, 202 can be generated by the above method using images 203, 204 that include at least two scales 1. [Explanation of symbols]

[0065] 1 Standard standard 10 Standard Rule Set 100 Image analysis device 101 Target coordinate determination unit 102 Image generation unit 103 Image synthesis unit 104 Display section 105 Display device 1a Standard standard 1b Standard standard 1c standard standard 1d standard 2 Standard body 201,202,205 Orthoimages 203,204 images 21 End 22 Central part 24 ends 3 1st recognition part 30 Structures 4 Second recognition part 41 Dashed frame 43 Dashed frame 44 dashed frame 4a Unit Recognition Section 4b Third recognition part 4d Unit Recognition Section 4e Dashed frame 4f dashed frame 5 seats 5 Second recognition part 51 edge

Claims

1. a rod-shaped scale body; at least three first identification marks on at least both ends of the scale body and on the longitudinal center of the scale body, the first identification marks indicating the length of the scale body; a second identification portion disposed on a straight line passing through the at least three first identification portions, for identifying the scale body on which the first identification portions are displayed; the first recognition portion is larger than the second recognition portion; It has a rod shape that does not bend when placed on the construction site. A standard scale characterized by:

2. The first recognition unit and the second recognition unit are configured to have a circular outline.

2. The measuring scale according to claim 1 .

3. The second recognition unit includes a plurality of unit recognition units each having a different aspect of at least one of color and shape, and each unit recognition unit has a unique aspect.

3. A measuring scale according to claim 1 or 2.

4. The second recognition unit further includes a third recognition unit for correcting an error during recognition by the second recognition unit.

3. A measuring scale according to claim 1 or 2.

5. It is used to generate orthoimages by processing the images obtained by capturing.

3. A measuring scale according to claim 1 or 2.

6. A scale set comprising at least two scales according to claim 1 or 2, The second recognition portion of each of the scales includes a plurality of unit recognition portions that are different in at least one aspect of color or shape, and each of the scales has a unique aspect. A scale set characterized by:

7. a rod-shaped scale body; at least three first identification parts displayed on at least both ends of the scale body and at the longitudinal center of the scale body, and which give the length of the scale body; and a second identification part arranged on a line passing through the at least three first identification parts for identifying the scale body displaying the first identification parts, and an object coordinate determination part which determines an object coordinate system at the actual construction site, based on a specified scale which is one of the at least two scales and which is arranged so as to be parallel to the center line in the image, based on a scale coordinate system which is based on the first identification parts of the scale which has a rod shape without bending when arranged at the construction site, and a photograph coordinate system which is based on the first identification parts of the scale in at least one image of the construction site which includes at least two scales; an image generating unit that generates an orthoimage corresponding to the image based on the target coordinate system determined by the target coordinate determining unit and the image; An image analysis device characterized by:

8. The target coordinate determination unit determining, for each scale, the parameters included in a third relationship that indicates the relationship between the photograph coordinate system, the object coordinate system, and the scale coordinate system, the third relationship being derived from a first relationship that indicates the relationship between the object coordinate system and the scale coordinate system and that includes parameters that vary for each image, and a second relationship that indicates the relationship between the object coordinate system and the photograph coordinate system; determining the object coordinate system based on the determined parameters, the first relationship, the second relationship, and the photograph coordinate system; 8. The image analysis device according to claim 7.

9. The parameters include a rotation angle of the target scale, which is the object of the parameter determination, in a horizontal plane relative to the predetermined scale, and a translation amount of the target scale relative to the predetermined scale.

9. The image analysis device according to claim 8.

10. The target coordinate determination unit determines the parameters by solving the third relationship that is established for each of the scales and each of the first recognition units.

10. The image analysis device according to claim 8 or 9.

11. An image synthesis unit is provided that synthesizes orthoimages obtained from at least two images of different regions and creates a single orthoimage including the respective regions.

11. The image analysis device according to claim 8, wherein:

12. an imaging step of acquiring at least one image by capturing an image at the construction site including at least two rod-shaped scales, at least three first identification parts displayed on at least both ends of the scale and at the longitudinal center of the scale, which give the length of the scale, and a second identification part arranged on a straight line passing through the at least three first identification parts and for identifying the scale body displaying the first identification parts, the scale having a rod shape that does not bend when placed at the construction site, and at least one of the scales arranged so as to be parallel to the center line; an object coordinate determination step of determining an object coordinate system at the actual construction site that is based on a predetermined scale, which is one of the at least two scales, based on a scale coordinate system that is based on the first recognition unit on the scale and a photograph coordinate system that is a coordinate system that is based on the first recognition unit on the scale in the image; an image generating step of generating an orthoimage corresponding to the image based on the target coordinate system determined in the target coordinate determining step and the image. The image analysis method is characterized by:

Images