JP2001099631A - Plane flatness measuring method and measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plane flatness measuring method and measuring device capable of easily and accurately measuring flatness of a plane. SOLUTION: A measurement car 10 moving in longitudinal direction on a plane comprises a running distance sensor 16 detecting the moving distance, a light source 13 casting light to a spot light region S on a road surface D, an imaging camera 14 picturing the reflection image from the spot light region S and a recording device for recording the picture image. When the initial position of a measuring car moved from the spot light region S, the image data is recorded in the recording device in turn of picturing. The recorded image data are reproduced with an image reproducer 21, inputted in a (b) image register 22 and a (b) image register 23. The image line in the front of progressing direction of image data continuing from bL2 cut register 24 and aL1 cut register 25 and the image line in the back of the progressing direction of the back image data are read out in turn and matched with a matching register. Correction quantity at the moment is obtained and data is corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for measuring flatness of a flat surface having irregularities such as a road surface.

[0002]

2. Description of the Related Art
As a method for measuring the straightness of an object to be measured on a straight line, as shown in JP-B-61-33364 (FIG.
), Two displacement gauges 6 and 7 are arranged in parallel at a short pitch toward the DUT 3 on a slide 4 movably engaged with a linear guide 5 parallel to the DUT 3, and the slide 4
Is sent once in one direction over the entire length of the measurement length for one pitch, the distance between the two displacement gauges 6, 7 and the object 3 is measured at each position by the respective displacement gauges 6, 7, and the data is processed. Thus, there is known a method (hereinafter, referred to as a sequential two-point method) for determining the straightness of an object to be measured together with a linear guide. According to this sequential two-point method, straightness curves of both the linear guide and the DUT can be obtained independently, and the straightness of the DUT can be accurately measured even if the guide is not straight. It was very convenient.

Further, according to the light cutting method, as shown in FIG. 6, a flat light-projecting surface is irradiated with slit-like light from above in a vertical direction to form a secondary light source (bright line) formed on the surface of the flat surface.
Is distorted when viewed from a position other than the irradiation axis. By analyzing this distortion, the unevenness of the plane can be clarified.

By combining the above two methods, it is conceivable to measure the unevenness of a plane. That is, as shown in FIG. 4 as a reference example, the vertical displacement (FIG. 4 (b)) of the transverse line (FIG. 4 (a)) obtained by the light By combining them, a three-dimensional uneven shape of a plane (Fig. 4
(C)) can be measured. However, according to the flatness measurement method, data by two measurement methods having different properties is required, so that data processing is complicated and a data processing system is complicated. Further, since the crossing line data is connected at points of the vertical line data, accuracy of the vertical line data is required, and the vertical line measuring system becomes expensive.

By the way, regarding the behavior of a vehicle traveling on a road, the vertical fluctuation is much larger than the horizontal fluctuation, and the rolling (rotation about the vertical axis) of the vehicle is pitching. (Rotation about the horizontal axis). The present inventor has considered that it is possible to measure the uneven shape of the road surface by correcting the vertical fluctuation and rolling of the vehicle in consideration of such a property at the time of traveling of the vehicle, The present invention has been made. That is, an object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to provide a flatness measuring method and a flatness measuring apparatus which can easily and accurately measure the flatness of a flat surface.

[0006]

Means for Solving the Problems and Effects of the Invention In order to achieve the above object, the structural feature of the invention according to the first aspect is that a moving body is moved in a vertical direction on a plane to reduce the flatness of the plane. A flatness measurement method for measuring, wherein a predetermined light beam is projected on a plane in a moving direction of the moving body by a light projecting means arranged on a moving direction side of the moving body and partitioned in a vertical direction and a horizontal direction. A rectangular light projecting area is formed, and a reflected image from the light projecting area is photographed by photographing means arranged on the moving direction side of the moving body and obliquely to the light projecting direction, and the initial position of the moving body and Each time the moving body moves at the light emitting area pitch, the image photographed by the photographing means is recorded as image data in the image recording means in the photographing order. The image line on the front side of the traveling direction The subsequent image data when the image line of the subsequent image data is superimposed on the image line of the preceding image data on the front side in the traveling direction of the image data of the preceding image data sequentially read out. A pattern matching operation for calculating a two-dimensional displacement of the image line in the horizontal plane and a rotational displacement with respect to the horizontal plane as a correction amount is continuously performed.

According to the first aspect of the present invention, the light emitting means disposed on the moving direction side of the moving body is divided into a predetermined vertical and horizontal direction in the moving direction of the moving body. The light is projected into the rectangular projection area of
The reflected image from the projected light projecting area is photographed by photographing means arranged on the moving direction side of the moving body and obliquely to the light projecting direction, and the initial position of the moving body and the light projection of the moving body For each movement at the area pitch, a video image taken by the imaging means is recorded in the video recording means as image data in the order of imaging. With respect to the image data recorded in this way, the pattern line matching operation sequentially reads out the image line on the front side in the traveling direction of the preceding image data and the image line on the rear side in the traveling direction of the subsequent image data. By superimposing the image line of the subsequent image data on the image line of the previous image data, a correction amount can be obtained by calculating a two-dimensional displacement in a horizontal plane and a rotational displacement with respect to the horizontal plane. By correcting the image data by the amount, the flatness of the plane can be easily obtained.

As a result, according to the first aspect of the present invention, a single type of image data of a reflected image from a light projecting area projected by the light projecting means is processed, and the sequential two-point method is applied progressively. Since data of two lines that can be obtained can be acquired, data processing can be performed easily and inexpensively. Also,
The image line on the front side in the traveling direction of the continuous preceding image data and the image line on the rear side in the traveling direction of the subsequent image data are sequentially read out,
By superimposing the subsequent image line on the read previous image line, the correction amount can be obtained by calculating the two-dimensional displacement in the horizontal plane and the rotational displacement with respect to the horizontal plane, so that the data accuracy is improved. be able to. Also,
Since the flatness of the road can be obtained at low cost and with high accuracy, this data can be used for improving the riding comfort of the vehicle and realizing a highly safe road.
Further, the present invention can be used for realizing a road that can reduce speed changes such as rapid acceleration / deceleration of a vehicle, and can suppress the generation of carbon dioxide due to rapid acceleration / deceleration, and can be effectively used for environmental conservation.

[0009] The second aspect of the present invention is characterized in that a moving body that moves in a vertical direction on a plane, distance detecting means for detecting a moving distance of the moving body, and a moving direction side of the moving body. A light projecting means mounted to project light on a plane in the moving direction of the moving object to form a predetermined rectangular light projecting area partitioned in a vertical direction and a horizontal direction; A photographing unit mounted obliquely to the direction, photographing a reflected image from the light projecting area, and an image recording unit recording the photographed image by the photographing unit as image data,
When it is detected by the initial position and the distance detecting means of the moving body that the moving body has moved in the vertical direction at the light emitting area pitch,
A measurement moving body including image recording control means for recording the image photographed by the photographing means in the image recording means in the order of photographing; and, for the recorded image data, an image on the front side in the traveling direction of the preceding image data successive in the recording order. A sequential image line reading means for sequentially reading lines and an image line on the rear side in the traveling direction of the subsequent image data; and a successive image line read out by the sequential video line reading means on the preceding image line in the traveling direction of the preceding image data. Image data comprising correction amount calculating means for calculating a two-dimensional displacement of the image line of the subsequent image data in the horizontal plane and a rotational displacement with respect to the horizontal plane when the image lines of the data are superimposed on each other to obtain a correction amount And a processing device.

[0010] In the second aspect of the present invention, the light projecting means provided on the moving direction side of the moving body that moves vertically on the plane is used to move the moving body in the vertical direction in the moving direction of the moving body. The light is projected toward a predetermined light projecting area dividing the direction and the lateral direction, and is projected by the photographing means arranged on the moving direction side of the moving body and obliquely to the light projecting direction. A reflected image from the projected light projection area is captured. Further, when it is detected by the initial position and distance detecting means of the moving body that the moving body has moved in the vertical direction at the pitch of the light projecting area, the image photographed by the photographing means is displayed based on the control of the image recording means. The image data is recorded in the recording means in the order of photographing.

With respect to the recorded video, the image line on the front side in the traveling direction of the preceding image data and the image line on the rear side in the traveling direction of the subsequent image data are sequentially read out by the sequential video line reading means. When the image line of the subsequent image data is superimposed on the image line on the front side in the traveling direction of the preceding image data read by the sequential video line reading means, two-dimensional image lines of the image lines of the subsequent image data in the horizontal plane And the rotational displacement with respect to the horizontal plane are calculated by the correction amount calculating means to obtain the correction amount. Based on this correction amount, the recorded video is sequentially corrected, and the flatness of the unevenness of the plane can be accurately obtained.

As a result, according to the second aspect of the present invention, a single type of image data, ie, a reflected image from a light projecting area projected by the light projecting means, is processed, and the sequential two-point method is applied in a progressive manner. Since data of two lines that can be obtained can be acquired, a data processing system can be provided simply and inexpensively. In addition, the image line on the front side in the traveling direction of the continuous preceding image data and the image line on the rear side in the traveling direction of the subsequent image data are sequentially read, and the subsequent image line is superimposed on the read previous image line. Accordingly, the correction amount can be obtained by calculating the two-dimensional displacement in the horizontal plane and the rotational displacement with respect to the horizontal plane, so that the data accuracy can be improved. In addition, by obtaining data of road flatness with high accuracy by using the flatness measuring apparatus, the data can be used for improving the riding comfort of the vehicle and realizing a highly safe road. Further, the present invention can be used for realizing a road that can reduce speed changes such as rapid acceleration / deceleration of a vehicle, and can suppress the generation of carbon dioxide due to rapid acceleration / deceleration, and can be effectively used for environmental conservation.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show a flatness measuring apparatus for measuring the flatness of a road surface D of a road according to the embodiment. Vehicle 10 and image data processing device 20 constituting
1 is shown in a block diagram.

As shown in FIG. 1, the measuring vehicle 10 has a body 1
A support portion 12 protruding in the traveling direction is provided on the front side of the vehicle traveling direction F, and a rod-shaped light source 13 extending in the traveling direction at the front end and at the center in the lateral direction is provided. The light source 13 emits linear light such as laser light to the road surface D,
It forms a horizontally long rectangular light projecting area S which is partitioned by a distance x in the vertical direction (vehicle traveling direction) and by a distance y in the horizontal direction. An image camera 14 is provided on the front surface of the main body 11 below the support portion 12. The image camera 14 is on the same vertical plane as the light source 13 with respect to the traveling direction, and the road surface D
Is attached to the light projecting area S at a predetermined angle with respect to the light projecting area S. The image camera 14 captures the reflected light from the light projecting area S so as to cover the light projecting area S. The output side of the image camera 14 is the recording device 1
5 is connected.

The recording device 15 includes a distance processing unit 17 described later.
Upon receiving a determination signal indicating that the measuring vehicle 10 has moved a unit distance u in the traveling direction with the light projecting area S as one pitch, image data P that is a reflected image of the light projecting area S is recorded. . The image camera 14 is not limited to a video camera and a digital camera, but may be an image plate, a film-type optical camera, or any other device capable of capturing two-dimensional information. However, video cameras, digital cameras, etc.
It is desirable that the electrical processing be easy.

A traveling distance sensor 1 such as a photoelectric sensor or a magnetic sensor for detecting the traveling distance of the vehicle based on the rotation of the wheels is provided near the wheel 11a of the measuring vehicle 10.
6 are provided. The mileage sensor 16 is a wheel 11
The traveling distance of the measuring vehicle 10 is detected by detecting the rotation state of a. The traveling distance sensor 16 is connected to a distance processing unit 17 including a comparator. The distance processing unit 17 processes a signal from the traveling distance sensor 16 to determine whether or not the measuring vehicle 10 has moved the unit distance u having the light projection area S as one pitch, and records the determination result in the recording. Output to the device 15. Further, the recording device 15 receives the determination result from the distance processing unit 17 and stores the image data in a CD each time the measuring vehicle 10 moves the unit distance u.
The data is stored in a recording medium 18 such as a ROM or an FD.

The image data processing device 20 is provided separately from the measuring vehicle 10, processes image data stored in the recording medium 18, and generates data indicating the flatness of the road surface D such as data indicating the flatness of the road surface D. Output. As shown in FIG. 2, the image data processing device 20 reads the data of the recording medium 18 and reads out the image data P ₁ (L ₁₁ , L ₁₂ ),
_{P 2 (L 21, L 22} ), P 3 (L 31, L 32) ... P
_n (L _n1 , L _n1 ). The suffix P indicates the order number of the unit distance u from the initial position, the first suffix L indicates the number of the unit distance u, and the second suffix “1” indicates the rear line with respect to the traveling direction. And "2" means a line on the front side with respect to the traveling direction. The b image register 22 and the a image register 23 are connected to the image reproducing device 21, and a continuous pair of image data is transferred to P ₁ (L ₁₁ , L _{11
12) -P 2 (L 21,} L 22), P 2 (L 21, L 22)
−P ₃ (L ₃₁ , L ₃₂ ),..., And output to the b image register 22 and the a image register 23 while shifting.

A bL2 extraction register 24 is connected to the b image register 22 so that the input image data P
₁ (L ₁₁ , L ₁₂ ) is cut out and output from the data L ₁₂ on the front side in the traveling direction, and the a image register 23
In it is connected aL1 cut register 25, cut out the traveling direction rear side of the data L ₂₁ of the image data P ₂ input _{(L 21,} L ₂₂₎ and outputs.

The bL2 extraction register 24 and the aL1 extraction register 25 are connected to a matching register 26. Matching register 26, the data _{L 12} from bL2 cut register 24, aL1 cut register 25
For superimposing the data L ₂₁ from the data L21 x direction (width direction), y-direction (traveling direction) and the rolling direction theta in ([Delta] x, [Delta] y, theta) is displaced. The matching register 26 is connected to the correction amount extraction register 27. The displacement amount Δ (Δ
x, Δy, θ) are input to the correction amount extraction register 27 and the displacement amounts (Δx, Δ
(y, θ), the shape information E of the edge of the image, the information F indicating the movement of the vehicle, and the property information C indicating the properties of the surface such as cracks, flaws, and lines on the road surface are output, and the shape is displayed. It is displayed on the register 28a and the property display register 28b.

Next, the operation of the above embodiment will be described. The measuring vehicle 10 irradiates a horizontally long rectangular light projecting area S with laser light from a rod-shaped light source 13 to a road surface D, and captures reflected light from the light projecting area S with an image camera 14.
The initial state image data P ₁ (L ₁₁ , L ₁₂ ) taken at the initial position of the measuring vehicle 10 is recorded on the recording medium 18 by the recording device 15. Thereafter, the measuring vehicle 10 starts traveling in the vertical direction F, and when traveling by the unit distance u of the light projecting area S, the distance processing unit 17 moves by the unit distance u in response to the detection of the traveling distance sensor 16 and records the result. 15 is output. The recording device 15 stores the measurement vehicle 10 from the distance processing unit 17.
There receives determination signal has moved a distance of one pitch projection area S from the initial position, is recorded on the recording medium 18 a reflected image of the second light projecting area S as image data P _2. Hereinafter, by the same procedure, the reflection image of the light projecting area S is continuously recorded on the recording medium 18 by the recording device 15 as image data P ₃ ... _Pn as shown in the figure.

Image data recorded on the recording medium 18
P₁, P₂, ……, P_nThe image data shown in FIG.
The data is processed in the data processing device 20. Image data processing
FIG. 3 shows the processing state of the image data in the device 20.
Shown in First, as shown in FIG.
Thus, the image data P of the recording medium 18₁, P₂, ……, P
_nIs read, and a pair of continuous image data₁(L
₁₁, L₁₂) -P₂(L₂₁, L₂₂)
B image register 22 and a image register connected to device 21
Input to the data 23. This pair of image data is P₁(L
₁₁, L₁₂) -P ₂(L₂₁, L₂₂)
BL2 extraction register 24 and aL1 extraction register
25, the image input to the bL2 extraction register
Data P₁(L ₁₁, L₁₂) Data L on the front side in the traveling direction
₁₂And is output to the aL1 extraction register 25.
Input image data P₂(L₂₁, L₂₂) Direction of travel
Rear data L₂₁And the matching register 26
Output to

In the matching register 26, bL2
The data _{L 1 2} from cut register 24, for superimposing the data _{L 21} from aL1 cut register 25, the data L21 x direction (width direction), y-direction (traveling direction) and in the rolling direction theta ([Delta] x, [Delta] y , Θ)
Displacement amount Δ1 = (Δx1, Δy1,
θ1) is input to the correction amount extraction register 27. In the correction amount extraction register 27, the displacement amount Δ1 = (Δx1, Δy
The edge of the image P2 is corrected based on (1, θ1).
In FIG. 3, P ₂ (L ₂₂ ) * Δ1 means that the image of the line L ₂₂ is corrected by the displacement Δ1.

Subsequently, the image data of the recording medium 18 is read, and a pair of continuous image data is represented by P ₂ (L ₂₁ , L ₂₁₎ .
₂₂ ) −P ₃ (L ₃₁ , L ₃₂ ), and are input to the b image register 22 and the a image register 23, and by the same processing as described above, the correction amount Δ2 = (Δx2, Δy2, θ)
2) is calculated. Similarly, correction amounts Δ3, Δ4,.
... Δn are calculated. In the correction amount extraction register 27, the images P ₁ and P ₂ corrected based on these correction amounts.
... _Pn edge shape information, vehicle motion information,
In addition, property information indicating the property of the surface such as cracks, scratches, and lines on the road surface is output, and the former two are displayed in the shape display register 28a, and the latter are displayed in the property display register 28b.

As described above, in the present embodiment, the light source 13 attached to the moving direction side of the measuring vehicle 10 moving in the vertical direction on the plane projects light onto the road surface D in the moving direction, and And a horizontally long rectangular light projecting area S is formed, and the image camera 14 is mounted on the moving direction side of the measuring vehicle 10 and obliquely to the light projecting direction.
As a result, a reflected image from the light projection area S is captured. Further, in response to a command that the distance processing unit 17 has detected that the measurement vehicle has moved in the vertical direction at the pitch of the light projecting area S in accordance with the initial position of the measurement vehicle 10 and the detection result of the traveling distance sensor 16, the image camera In the recording device 15, the video captured by the recording medium 1 is converted into three-dimensional image data.
8 are recorded in the order of photographing.

As described above, in the measuring vehicle 10, the recording medium 1
8, the preceding image data P _k and the subsequent image data P _{k + 1} that are consecutive in the recording order are sequentially read out by the image reproducing device 21 and input to the b image register 22 and the a image register 23, Further, in the bL2 extraction register 24 and the aL1 extraction register 25,
An image line L _{k2 on the} front side in the traveling direction of the previous image data P _k ;
The image line L on the rear side in the traveling direction of the subsequent image data P _{k + 1
k + 1 and k + 1} are sequentially read. Then, in the matching register 26, the preceding image line _Lk2 is _added to the subsequent image line Lk2.
_In order to superimpose _{k + 1,1} , the two-dimensional displacement of the subsequent image line in the horizontal plane and the rotational displacement with respect to the horizontal plane are calculated and input to the correction amount extraction register 27 as the correction amount Δk, and based on the correction amount Δk, The recorded images are sequentially corrected, so that the flatness of the unevenness of the plane can be accurately obtained.

As a result, according to the present embodiment, the light source 13
Since it is only necessary to process a single type of image data, that is, an image reflected from the light projecting area S projected by the method, the data processing system can be simplified and inexpensive. Also,
The image line on the front side in the traveling direction of the continuous preceding image data and the image line on the rear side in the traveling direction of the subsequent image data are sequentially read out,
In order to superimpose the image line of the subsequent image data on the image line of the read-out previous image data, a correction amount is obtained by calculating a two-dimensional displacement in a horizontal plane of the subsequent image line and a rotational displacement with respect to the horizontal plane. Therefore, the accuracy of data can be improved. In addition, since the flatness of the road can be obtained at low cost and with high precision, this data can be used for realizing a road that improves the riding comfort of the vehicle and enables comfortable driving. Further, the vehicle can be safely cornered at a set speed and can be used for designing a road with good drainage. Further, the present invention can be used to realize a road capable of reducing a speed change such as rapid acceleration / deceleration of a vehicle, and can suppress the generation of carbon dioxide due to rapid acceleration / deceleration, and can be effectively used for environmental conservation.

In the above embodiment, the light source 13
Is provided in the vertical upper part of the road surface D, and the image camera 14 is arranged so as to take an image from an oblique direction with respect to the vertical direction. The arrangement may be such that the road surface D is irradiated from the direction.

In the above embodiment, the measuring vehicle 1
0, the image taken by the image camera 14 is recorded as image data on the recording medium 18 by the recording device 15,
Although the image data processing device 20 provided separately processes the image data offline, the image data processing device 20 is mounted on the measuring vehicle 10 instead of this, so that the data captured by the image camera 4 can be processed online. Processing can be performed so that measurement results can be obtained at the same time as measurement.

Further, in the above-described embodiment, the present invention is applied to the measurement of the flatness of the road surface. However, the present invention is not limited to this and can be applied to the measurement of the flatness of other types of planes. In such a case, the shape and the like of the moving body are also appropriately changed. Further, according to the above-described embodiment, the measurement of the exercise time history of the vehicle can be performed together with the measurement of the flatness. As a result, the relationship between the road surface shape and the vehicle motion can be directly obtained, which can contribute to vehicle design. In addition, what is shown in the above-mentioned embodiment is an example, and various changes can be made without departing from the spirit of the present invention.

[Brief description of the drawings]

FIG. 1 is a schematic diagram schematically showing a measuring vehicle constituting a flatness measuring apparatus for measuring the flatness of a road surface according to an embodiment of the present invention.

FIG. 2 is a block diagram schematically showing an image data processing device constituting the flatness measurement device.

FIG. 3 is an explanatory diagram illustrating a process of processing image information in the image data processing device.

FIG. 4 is an explanatory diagram illustrating a measurement method in which a sequential two-point method and a light section method of a conventional example as a reference example are combined.

FIG. 5 is an explanatory diagram illustrating a measurement method using a sequential two-point method, which is a conventional example.

FIG. 6 is an explanatory diagram illustrating a measurement method using a light section method as another conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Measurement vehicle, 11 ... Car body, 11a ... Wheel, 13 ... Light source, 14 ... Image camera, 15 ... Recording device, 16 ... Travel distance sensor, 17 ... Distance processing part, 18 ... Recording medium, 20 ...
Image data processing device, 21: Image reproduction device, 22: b image register, 23: a image register, 24: bL2 extraction register, 25: aL1 extraction register, 26: matching register, 27: correction amount extraction register, 28a ...
Shape display register, 28b: property display register, S: light emitting area.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F065 AA47 CC40 FF01 FF04 FF67 GG04 GG16 JJ03 JJ08 JJ19 JJ26 QQ31 QQ38

Claims (2)

[Claims] 1. A flatness measuring method for measuring a flatness of a plane by moving a moving body on a plane in a vertical direction, comprising: a light projecting means provided on a moving direction side of the moving body. A predetermined rectangular light projecting area which is projected on a plane in the moving direction of the moving object and is partitioned in a vertical direction and a horizontal direction is formed, and a reflected image from the light projecting area is reflected on the moving direction side of the moving object. And photographing is performed by photographing means arranged obliquely to the light projecting direction, and photographed by the photographing means every time the moving body moves at the initial position and the light projecting area pitch. The recorded image data is recorded as image data in the image recording means in the order of photographing. For the recorded image data, an image line on the front side in the traveling direction of the preceding image data continuous in the recording order and the image line after the traveling direction of the subsequent image data Sequentially read out the image lines on the Two-dimensional displacement of the image line of the subsequent image data in the horizontal plane and rotation with respect to the horizontal plane when the image line of the subsequent image data is superimposed on the image line on the front side in the traveling direction of the output previous image data A method for measuring flatness, wherein a pattern matching operation for calculating a displacement and calculating a correction amount is continuously performed. 2. A moving body which moves in a vertical direction on a plane, a distance detecting means for detecting a moving distance of the moving body, and a plane attached to a moving direction side of the moving body in a moving direction of the moving body. A light projecting means for projecting upward to form a predetermined rectangular light projecting area partitioned in a vertical direction and a horizontal direction, and attached to a moving direction side of the moving body and oblique to the light projecting direction. A photographing means for photographing a reflected image from the light projecting area; an image recording means for recording a photographed image of the photographing means as image data; and an initial position of the moving body and the moving body by the distance detecting means. When it is detected that has moved in the light emitting area pitch in the vertical direction, a measurement moving body comprising image recording control means for recording the image photographed by the photographing means in the photographing order in the image recording means, Said recorded For the image data, sequential image line reading means for sequentially reading an image line in the forward direction of the preceding image data in the recording order and a rear image line in the forward direction of the subsequent image data, and the sequential image line reading means. When the image line of the subsequent image data is superimposed on the image line on the front side in the traveling direction of the read previous image data, the two-dimensional displacement of the image line of the subsequent image data in the horizontal plane and the horizontal plane A flatness measurement device, comprising: an image data processing device including a correction amount calculating unit that calculates a rotational displacement to obtain a correction amount.