JP2011123008A - Measuring method, measuring program, and measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure or continuously monitor an object to be measured such as a civil engineering structure or a building structure, easily with high accuracy using single image data, without requiring large-scale facilities or manpowers. <P>SOLUTION: A first target 40 wherein a position relationship between each fixed target mark 42 is known, and a different second target 50 are arranged on a structure 70 such as a civil engineering structure or a building structure, independently across a boundary of a crack 71 or the like existing on the structure 70, and image data 30 acquired by photographing an image thereof by a digital camera 90 from an optional position and a direction are input into an information processing device 10 and processed by a measuring program 20, to thereby measure a distance ΔL between the first target 40 and the second target 50 in a non-contact state to the structure 70 or the like from the single image data 30. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a measurement method, a measurement program, and a measurement apparatus.

For example, in civil engineering structures and building structures, local deformation or the like is continuously observed for the purpose of maintenance management and the like, which may be used as a measure for maintenance management and safety management measures.
In that case, the method of measuring the momentum and displacement / deformation of the object directly by human beings can be considered, but the object to be measured is the same as when the measurement location is at a high place such as the ceiling of the structure. Measurement is difficult when it is not easily accessible.

In addition, a method of collecting and measuring data at a remote location by installing a strain gauge can be considered, but the facility becomes large.
In addition, methods such as surveying equipment may be considered, but expensive surveying equipment and personnel for operation of the equipment are required, and in the case of continuous observation, surveying equipment and personnel are required each time. Preparation is required.

  For this reason, for example, as in Patent Document 1 and Patent Document 2, photogrammetry for taking a photograph of the measurement location can be considered.

Japanese Patent No. 3530978 Japanese Patent No. 4145484

  However, in conventional photogrammetry, it is necessary to place and photograph a number of ground control points of multiple photographs in the field, repeatedly superimpose and standardize to obtain 3D coordinate values, and advanced and complicated work is essential. However, there is a technical problem of requiring large equipment and a large number of personnel.

  The object of the present invention is to measure and continuously monitor an object to be measured such as a civil engineering structure or a building structure with a single image data easily and with high accuracy without requiring large-scale equipment and personnel. It is to provide a measurement technique capable of performing the above.

According to a first aspect of the present invention, there is provided a first target including at least three fixed targets arranged on an object to be measured and having a known two-dimensional positional relationship or a two-dimensional positional relationship set on an arbitrary scale; And a first step of obtaining a single image data by photographing so that an image of a second target including at least one target target arranged at an arbitrary position with respect to the first target is included in the same screen; ,
A second step of detecting, from the image data, two-dimensional coordinates of the fixed target and the target in a measurement plane determined by a plurality of the fixed targets;
A third step of calculating a distance between the fixed target and the target target based on the two-dimensional coordinates;
A measurement method including

According to a second aspect of the present invention, there is provided a first target including at least three fixed targets arranged on an object to be measured and having a known two-dimensional positional relationship or a two-dimensional positional relationship set on an arbitrary scale; And a first step of inputting single image data including an image of a second target including at least one target target disposed at an arbitrary position with respect to the first target in the same screen;
A second step of detecting, from the image data, two-dimensional coordinates of the fixed target and the target in a measurement plane determined by a plurality of the fixed targets;
A third step of calculating a distance between the fixed target and the target target based on the two-dimensional coordinates;
A measurement program for causing a computer to execute is executed.

According to a third aspect of the present invention, there is provided a first target including at least three fixed targets arranged on an object to be measured and having a known two-dimensional positional relationship or having a two-dimensional positional relationship set on an arbitrary scale; And input means for inputting image data including an image of a second target including at least one target target arranged at an arbitrary position with respect to the first target in the same screen;
Two-dimensional coordinates of the fixed target and the target target in a measurement plane determined by a plurality of the fixed targets are detected from a single image data, and the fixed target and the target target are detected based on the two-dimensional coordinates. Computing means for calculating the distance;
A measuring device including the above is provided.

  According to the present invention, measurement and continuous monitoring of an object to be measured such as a civil engineering structure and a building structure can be performed easily and with high accuracy using a single image data without requiring large-scale equipment and personnel. It is possible to provide a measurement technique capable of performing the above.

It is a conceptual diagram which shows an example of the system configuration and an effect | action of the measuring method and measuring program which are one embodiment of this invention, and a measuring device. It is a conceptual diagram which shows an example of a structure of the measuring device which implements the measuring method and measuring program which are one embodiment of this invention. It is a conceptual diagram which shows the structural example of the measurement file used with the measuring method and measuring program which are one embodiment of this invention, and a measuring device. It is a flowchart which shows an example of the whole process of the measuring method which is one embodiment of this invention. It is a flowchart which shows an example of the distance measurement process by the measurement program which is one embodiment of this invention. It is a conceptual diagram which shows an example of the image data of the orthogonal projection image in the measuring method which is one embodiment of this invention. It is a conceptual diagram which shows an example of the picked-up image of the diagonal direction in the measuring method which is one embodiment of this invention. It is a conceptual diagram which shows an example of the picked-up image of the diagonal direction in the measuring method which is one embodiment of this invention. It is a conceptual diagram which shows an example of the method of calculating | requiring the center coordinate of a target mark more precisely than an image. It is a conceptual diagram which shows an example of the coordinate definition in the measuring method which is one embodiment of this invention. It is a conceptual diagram which shows the collinear conditions in a back intersection method.

  In an embodiment of the present invention, as one aspect, a plane is set by a plurality of fixed targets, an image measurement technique for obtaining position coordinates in a single photograph and a distance measurement, and a precision distance measurement technique thereby, a movement amount The measurement technique is illustrated.

  In this aspect, one plane is formed from images of a plurality of fixed targets among three or more fixed targets and at least one target target image included in a photographic image of a measurement object photographed by a digital camera or the like. The two-dimensional coordinates of other target targets on this plane are acquired by image measurement.

  That is, if the two-dimensional coordinates on the plane of a plurality of fixed targets are known in advance on an arbitrary scale, the two-dimensional coordinates of other target targets on the same plane can be determined. The distance can be measured by calculating the distance between the two.

  If there is a discontinuous boundary between the fixed target and another target target, the fixed target and target target are photographed and measured before and after the boundary change, and the fixed target coordinates are set before and after the boundary change. To obtain the coordinates before and after the change of the boundary of the other target target, and calculate the distance between the fixed target and the target target before and after the change of the boundary. It can be measured.

That is, the deformation of the measurement object can be continuously measured with high accuracy from a position away from the measurement object simply and with no contact with the measurement object.
Thereby, according to this aspect, for example, in maintenance management such as a telescopic device provided in a road structure, the amount of movement following the traffic load or temperature change is compared with the design value, and the soundness is evaluated. When the amount of deformation increases, such as when evaluating structures such as rocks on slopes, cracks or cracks in concrete structures where the amount of deformation may change over time When monitoring the above, it is possible to provide a means for simply and precisely measuring from a remote point in a non-contact manner.

In addition, it is possible to provide a means for simple and highly accurate non-contact measurement of a deformation amount accompanied by a planar displacement.
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a conceptual diagram showing an example of the configuration and operation of a measurement method, a measurement program, and a measurement apparatus according to an embodiment of the present invention.
FIG. 2 is a conceptual diagram showing an example of the configuration of a measurement apparatus that implements a measurement method and a measurement program according to an embodiment of the present invention.

FIG. 3 is a conceptual diagram showing a configuration example of a measurement file used in a measurement method, a measurement program, and a measurement apparatus according to an embodiment of the present invention.
As illustrated in FIG. 1, in the measurement method according to the present embodiment, the first target 40 and the second target 50 are formed in a structure 70 such as a civil engineering structure or a building structure, for example, a crack existing in the structure 70. The image data 30 obtained by photographing these images from an arbitrary position and direction with the digital camera 90 is input to the information processing apparatus 10 and the measurement program 20 to be described later. In this way, the distance ΔL between the first target 40 and the second target 50 is measured from the single image data 30 without contact with the structure 70 or the like.

  In the case of the present embodiment, the digital camera 90 is composed of, for example, a commercially available digital still camera, and the image data 30 obtained from the digital camera 90 includes, in addition to image information, a lens focal length f, the number of pixels, The incidental information such as the image size is also recorded in a predetermined format (for example, Exif which is an image file format standard for digital still cameras) and input to the information processing apparatus 10.

Note that a digital video camera may be used as the digital camera 90, and a still image of one frame may be used as the image data 30.
The first target 40 according to the present embodiment includes, for example, three or more fixed target marks 42 on the surface of a white base material 41 whose back surface is made of an adhesive resin film or the like. It is created by printing in relation.

  Similarly, the second target 50 is, for example, one or more target target marks 52 are known, for example, black, on the surface of a white base material 51 made of an adhesive resin film, mount, metal plate, or the like. It is created by printing in positional relationship.

  On the other hand, as illustrated in FIG. 2, the information processing apparatus 10 as a measurement apparatus according to the present embodiment includes, as an example, a commercially available personal computer or the like, and includes a microprocessor 11, a main memory 12, a storage device 13, and a display. 14, a keyboard 15, an external input / output interface 16, and the like are connected by an information transmission path 17.

  As a central processing unit, the microprocessor 11 implements various processes exemplified by flowcharts described later by executing a measurement program 20 stored in the main memory 12.

  The main memory 12 is composed of, for example, a semiconductor memory and holds programs and data such as a measurement program 20 accessed by the microprocessor 11 and basic software (not shown).

The storage device 13 is composed of, for example, a non-volatile recording medium, and holds data such as a measurement file 60 and image data 30 described later.
The display 14 visualizes and presents information to the user of the information processing apparatus 10.

The keyboard 15 provides an information input interface to the user together with input means such as a mouse (not shown).
The external input / output interface 16 has a function of exchanging information such as image data 30 with the digital camera 90 via a wired, wireless, or light communication medium.

  In the case of the information processing apparatus 10 of the present embodiment, the storage device 13 stores a measurement file 60 for recording measurement results regarding the first target 40 and the second target 50 described above.

  As illustrated in FIG. 3, the measurement file 60 stores an imaging date / time 61, first target position information 62, second target position information 63, an inter-target distance 64, and an orthogonal projection image 65 in association with each other. Has been.

The shooting date and time 61 records the shooting date and time of the first target 40 and the second target 50 arranged on the structure 70 as described above.
In the first target position information 62, position information of individual fixed target marks 42 of the first target 40 is recorded.

In the second target position information 63, position information of the target target mark 52 of the second target 50 is recorded.
In the inter-target distance 64, a distance ΔL between the centers of one fixed target mark 42 of the first target 40 and one target target mark 52 of the second target 50 is recorded.

In the orthographic image 65, an orthographic image obtained by converting a captured image from an arbitrary direction of the first target 40 and the second target 50 into a captured image from a facing direction is recorded.
By displaying the orthogonal projection image 65 on the display 14 as necessary, the workability when the user browses the image data 30 visually is improved.

Hereinafter, an example of the operation of the measurement method, the measurement program, and the measurement apparatus according to the present embodiment will be described.
FIG. 4 is a flowchart illustrating an example of the entire process of the measurement method of the present embodiment, and FIG. 5 is a flowchart illustrating an example of distance measurement processing by the measurement program 20 of the present embodiment therein.

First, the first target 40 and the second target 50 as described above are prepared and prepared (step 210).
As described above, at the time of this creation, in the first target 40, a plurality of fixed target marks 42 are arranged on the two axes perpendicular to each other with the one fixed target mark 42 as the center. Is done. The positional relationship (actual coordinate values) of the plurality of fixed target marks 42 in the first target 40 is measured and known.

  Next, as shown in FIG. 6, for example, with respect to a crack 71 on an arbitrary plane of the structure 70, a first target 40 (hereinafter referred to as a group A target if necessary) and a second target 50. (Group B target) is installed (step 220).

In the case of the present embodiment, as described above, it is assumed that the target of group A is known in real coordinates and the distance between the targets is obtained in advance or is set freely.
Next, the first target 40 and the second target 50 arranged in the structure 70 are taken as a single image from any direction so that they enter the same screen (for example, FIG. 7 or FIG. 8), and the image data 30 Is stored in the storage device 13 of the information processing apparatus 10 (step 230).

Next, the information processing apparatus 10 causes the measurement program 20 to perform measurement processing based on the image data 30 (step 240).
FIG. 5 is a flowchart showing an example of processing by the measurement program 20.

In the case of the present embodiment, the measurement program 20 includes a target center detection function 21, a projective transformation function 22, and a distance measurement function 23.
The measurement program 20 reads the image data 30 from the storage device 13 (step 241).

  Next, with respect to each target (individual fixed target mark 42 and target target mark 52) of the image data 30, the target center coordinate (image coordinate) is obtained more precisely than the image by the target center detection function 21 as shown in FIG. .

  That is, the target center detection function 21 recognizes an adjacent group of pixels 31 having brightness equal to or higher than a threshold (thresh) from the image data 30 as one fixed target mark 42 or target target mark 52, and Based on the peak value (peak) and its coordinate position, the centroid position of the adjacent group is calculated, and this centroid position is determined as the center of the fixed target mark 42 or the target target mark 52 (step 242).

  In this way, by obtaining the area centroid of the image portion of each fixed target mark 42 and target target mark 52, the fixed target mark 42 and Image coordinates of the center position of each target mark 52 can be obtained (step 242).

  Next, the measurement program 20 uses the projective transformation function 22 to obtain the actual coordinates of the fixed target mark 42 of the first target 40 whose positional relationship (real coordinates) is known, which is obtained in the above-described step 242, and in step 242. Using the image positions (center positions) of the individual fixed target marks 42 thus obtained, the camera (lens center) position (X0, Y0, Z0) at the time of photographing the image data 30 and the coordinates of each coordinate axis are obtained by the backward intersection method. The amount of rotation (ω, φ, κ) is calculated (step 243).

  That is, based on the premise of Step 210 and Step 220 described above, all the fixed target marks 42 and the target target marks 52 are on the same plane, and the coordinates of the group A targets (fixed target marks 42) are known. Collinear conditional expressions (target position, camera shooting position and target image coordinates) in photogrammetry from the image coordinates of the center position of each of the three fixed target marks 42 and the known position coordinates (actual coordinates) of the fixed target mark 42. From this relational expression), it is possible to determine the shooting position and shooting direction of the camera by the backward intersection method.

Details of this calculation are shown below. FIG. 10 is a conceptual diagram showing an example of coordinate definition, and FIG. 11 is a conceptual diagram showing collinear conditions in the backward intersection method.
When coordinates are defined as shown in FIG. 10, the procedure for obtaining the photographing position and direction angle of the digital camera 90 (both are referred to as external orientation elements) by the backward intersection method is as follows.

In FIG. 11, the lens center, the actual point P on the structure 70, and the position of the point p on the image data 30 are shown.
In FIG. 10, the photographic image coordinate system (x, y) whose origin is the lens center point C, the real coordinate system (X, Y, Z), the lens focal length f, and the camera direction angle (ω, φ, κ). The following relational expression (1) holds.

  In the above equation (1), ω, φ, and κ represent the rotation amount of the coordinate axis, respectively, the rotation angle (ω) with respect to the photographing axis (lens optical axis), and the rotation angle (φ) in the vertical direction of the photographing axis. The rotation angle (κ) in the horizontal direction is shown. Further, (X0, Y0, X0) indicates the actual coordinate value of the lens center point C. λ is an appropriate coefficient.

  If the rotating part of the above equation (1) is arranged as in the following equation (2), the above equation (1) can be expressed as in the following equation (3).

  When this equation (3) is expanded and λ is eliminated, the following equations (4) and (5) can be rewritten.

  Real coordinates (X1, Y1, 0), (X2, Y2, 0) of three points (three fixed target marks 42) with respect to the unknowns (X0, Y0, Z0) and (ω, φ, κ) to be obtained , (X3, Y3, 0), (As a condition, since the three points are on the same plane, the Z coordinate is 0), and the coordinates of the three points on the image (x1, y1), (x2, y2) , (X3, y3) and the lens focal length f are known, the unknowns are obtained by combining them.

  Although it is conceivable to include a correction term to exclude the influence of lens distortion in the collinear conditional expression, in many cases, the degree of influence is large when shooting with a short focus lens, and that with a long focus lens. The degree is extremely small.

  In the present embodiment, the influence of lens distortion can be kept below the measurement accuracy by taking a picture using a long focus lens in the digital camera 90 while taking into account the positional relationship with the subject.

  Note that, for example, there may occur a case where the shooting position of the camera obtained by calculation from the coordinates of the three fixed target marks 42 whose coordinates are known is unstable due to the measurement error of the center coordinates of each fixed target mark 42. Targets with known coordinates are four points (fourth fixed target mark 42 is provided on the first target 40), and each of a plurality of planes determined by a combination of arbitrary three points among the four points of the target Then, by deriving an equation from the collinear conditional expression and solving it by the least square method, by determining one plane where the first target 40 and the second target 50 exist, the error distribution is optimized and stable. The photographing position of the camera can be obtained.

  Next, the measurement program 20 performs the projective transformation of the photographed image data 30 from the photographing position of the digital camera 90 and the position of the target of the A group by the projective transformation function 22, and the first target 40 and the second target. An image obtained by photographing 50 from the front is created and recorded in the orthogonal projection image 65 of the measurement file 60 (step 244).

That is, the image data 30 photographed from an oblique direction as shown in FIGS. 7 and 8 is converted into image data 30 as depicted in FIG. 6 photographed from the front.
If an orthographic image is unnecessary, if only the image coordinates of the fixed target mark 42 and the target target mark 52 are subjected to projective transformation, the following projection transformation of the entire pixel 31 of the image data 30 is not performed. The coordinates (x, y) of the fixed target mark 42 and the target target mark 52 used in step 245 can be provided.

  Next, the measurement program 20 obtains the coordinates (x, y) of the target of the A group and the target of the B from the orthogonal projection image converted in the above step 244 by the distance measurement function 23, and calculates those coordinate values. Then, a distance ΔL between the targets is obtained (step 245).

This distance ΔL is, for example, the distance between the target target mark 52 and the most recent fixed target mark 42.
For example, when a 60 cm wide image is taken with a digital camera 90 having a lateral width of 3000 pixels equipped with an appropriate lens, one pixel indicates 0.2 mm. As described in FIG. 9 and step 242, if the center coordinates of each of the fixed target mark 42 and the target target mark 52 can be obtained in units of 1/10 pixels, the distance ΔL can be measured with a resolution of 0.02 mm. It becomes possible.

  That is, as an example, the image data 30 photographed by the digital camera 90 having 6 million pixels is data of 3000 pixels wide and 2000 pixels vertically. When an appropriate lens is selected and a range of 30 cm × 20 cm is photographed, the size of one pixel is 0.1 mm × 0.1 mm.

  If the images of each of the fixed target mark 42 and the target target mark 52 are taken with a size of about 20 pixels in diameter, the center of the target mark is calculated by detecting the center of gravity. It is possible to calculate with a detection accuracy of about 1/10. For this reason, the position determination accuracy of about 0.02 mm can be set.

The above is an example of the distance measurement process by the measurement program 20 in step 240.
Returning to the flowchart of FIG. 4 described above, the distance ΔL obtained in step 240 is recorded as the inter-target distance 64 in the measurement file 60 by the measurement program 20.

  The center position of each fixed target mark 42 of the first target 40 is recorded in the first target position information 62, and the center position of each target target mark 52 of the second target 50 is the second target position information 63. To be recorded.

  Then, the user compares the distance ΔL obtained from each of the plurality of image data 30 photographed before and after the pair of the same first target 40 and second target 50 arranged in the structure 70, Information on displacement such as enlargement of the crack 71 in the structure 70 can be obtained.

Furthermore, in the case of the present embodiment, the measurement program 20 can automatically determine the deformation of the structure 70 as follows.
That is, the measurement program 20 searches the measurement file 60 for a record of past image data 30 relating to the same first target 40 and second target 50 as the input image data 30, and is the second and subsequent image data 30 ( If it is determined that it is not the first shooting (step 260), the distance ΔL measured and recorded last time is compared with the distance ΔL obtained this time to calculate the difference E between them (step 270). ) When the difference E exceeds a predetermined determination threshold E0 (step 280), the user is warned of an increase in the distance ΔL, that is, an increase in deformation of the structure 70 (step 290).

In the flowchart of FIG. 4, the second and subsequent shootings for the same first target 40 and second target 50 pair are performed from step 230.
As described above, according to the measurement technique of the present embodiment, for example, a single image including images of the first target 40 and the second target 50 arranged with the crack 71 of the structure 70 interposed therebetween in one screen. Only by photographing the data 30, the distance ΔL between the first target 40 and the second target 50 can be accurately measured without contact at any position with respect to the structure 70.

  As a result, by continuously photographing the image data 30 of the same first target 40 and second target 50 one after another, displacement such as expansion of the crack 71 in the structure 70 can be accurately measured and monitored.

In addition, since the structure 70 is only photographed step by step with the digital camera 90, a large facility such as a surveying instrument or a large number of operation personnel is not required.
That is, according to the present embodiment, measurement of an object to be measured such as a civil engineering structure or a building structure can be easily and accurately performed with a single image data without requiring large-scale equipment and personnel. Measurement technology capable of continuous monitoring can be provided.

Needless to say, the present invention is not limited to the configuration exemplified in the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the center positions of the fixed target mark 42 and the target target mark 52 can be determined on a virtual plane in which the coordinate values of the plurality of fixed target marks 42 of the first target 40 are freely set.

In this case, the distance ΔL is measured as a ratio with respect to the distance between the fixed target marks 42 of the first target 40.
Further, instead of arranging the first target 40 and the second target 50, images of components having known dimensions existing in the structure 70 may be used as the first target 40 and the second target 50.

  In that case, the arrangement | positioning operation | work of the 1st target 40 and the 2nd target 50 can also be skipped, and there exists an advantage which can implement | achieve further labor saving in measurement and monitoring of the deformation | transformation of the structure 70.

DESCRIPTION OF SYMBOLS 10 Information processing apparatus 11 Microprocessor 12 Main memory 13 Storage apparatus 14 Display 15 Keyboard 16 External input / output interface 17 Information transmission path 20 Measurement program 21 Target center detection function 22 Projection conversion function 23 Distance measurement function 30 Image data 31 Pixel 40 First Target 41 Base material 42 Fixed target mark 50 Second target 51 Base material 52 Target target mark 60 Measurement file 61 Shooting date and time 62 First target position information 63 Second target position information 64 Inter-target distance 65 Orthographic image 70 Structure 71 Crack 90 Digital camera

Claims (13)

A first target including at least three fixed targets arranged on the object to be measured and having a known two-dimensional positional relationship or having a two-dimensional positional relationship set on an arbitrary scale; and arbitrary with respect to the first target A first step of obtaining a single image data by photographing so that an image of a second target including at least one target target arranged at the position is included in the same screen;
A second step of detecting, from the image data, two-dimensional coordinates of the fixed target and the target in a measurement plane determined by a plurality of the fixed targets;
A third step of calculating a distance between the fixed target and the target target based on the two-dimensional coordinates;
A measurement method comprising: The measurement method according to claim 1,
Further, a fourth step of determining a deformation amount of the object to be measured by detecting a change in the distance between the fixed target and the target target obtained from each of the plurality of image data photographed at different times. A measurement method comprising: The measurement method according to claim 1,
The first target includes four or more fixed targets,
In the second step, the measurement plane is determined by a least square method from a plurality of planes determined by an arbitrary combination of three of the four or more fixed targets. The measurement method according to claim 1,
In the first step, the image data is acquired by photographing the object to be measured from an arbitrary direction, and in the second step, the image data is converted into the measured object by coordinate conversion of the two-dimensional coordinates. A measurement method, wherein the image data is converted into a quasi-orthogonal image directly facing an object. The measurement method according to claim 1,
A measurement method characterized in that the image data is obtained by photographing the first target and the second target arranged on the object to be measured from an arbitrary direction with a digital camera. The measurement method according to claim 1,
In the second step, the coordinate value of the two-dimensional coordinate in the measurement plane is determined by a ratio with reference to one fixed target,
In the third step, the distance between the fixed target and the target target is measured as a ratio.   A measurement program for causing a computer to execute the first step, the second step, and the third step in the measurement method according to claim 1. A first target including at least three fixed targets arranged on the object to be measured and having a known two-dimensional positional relationship or having a two-dimensional positional relationship set on an arbitrary scale; and arbitrary with respect to the first target Input means for inputting image data including an image of a second target including at least one target target arranged at the position of the same target on the same screen;
Two-dimensional coordinates of the fixed target and the target target in a measurement plane determined by a plurality of the fixed targets are detected from a single image data, and the fixed target and the target target are detected based on the two-dimensional coordinates. Computing means for calculating the distance;
A measuring device comprising: The measuring device according to claim 8, wherein
The computing means detects a change in the distance between the fixed target and the target target obtained from each of the plurality of image data photographed at different times, and determines a deformation amount of the object to be measured. A measuring device characterized by that. The measuring device according to claim 8, wherein
The first target includes four or more fixed targets, and the calculation means calculates the measurement plane by a least square method from a plurality of planes determined by a combination of any three of the four or more fixed targets. A measuring device characterized in that The measuring device according to claim 8, wherein
The computing means converts the image data photographed from an arbitrary direction with respect to the measured object into a quasi-orthogonal image facing the measured object by coordinate conversion of the two-dimensional coordinates. A characteristic measuring device. The measuring device according to claim 8, wherein
The input device is an input / output interface to which a digital camera is connected and which inputs the image data from the digital camera. The measuring device according to claim 8, wherein
The calculation means obtains a coordinate value of the two-dimensional coordinates on the measurement plane by a ratio based on one fixed target, and measures the distance between the fixed target and the target target as a ratio. A measuring device.