JP2006275984A - Method of measuring displacement of high-voltage tower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of measuring displacement of a high-voltage tower that can easily and surely measure the displacement of the high-voltage tower and also intuitively recognize the displacement from acquisition information. <P>SOLUTION: A three-dimensional measurement method comprises a step for entering photographic image data, based on a plurality of photographs; a step for specifying a position to acquire a three-dimensional coordinate each photograph, on the basis of input photograph image data; a step for associating a position each photograph on the same point which has been specified; and a step for obtaining the three-dimensional coordinate, on the basis of the position on the same point which has been associated. The method includes a step for photographing the same specified point from at least two different points inside the high-voltage tower surrounded with four legs, by using a camera and a display step for performing a three dimensional display, on the basis of the three-dimensional coordinate obtained by means of the three-dimensional measurement method. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for measuring the displacement of a high-pressure tower.

  The high-voltage tower is an important infrastructure that supports society, such as supplying power to various places. Some of these high-voltage towers are displaced due to various factors such as natural disasters such as earthquakes and typhoons, changes in the surrounding environment such as location conditions, and aging of components over time. is there. For this reason, in order to ensure the safety of the high-pressure tower and prevent accidents such as collapse, a safety survey of the high-pressure tower is regularly conducted.

  For such a high-pressure steel tower that is displaced, an investigation is performed using, for example, a high-precision three-dimensional measuring instrument using laser light.

Patent Document 1 below shows an example of a measurement method and an apparatus for facilitating displacement measurement of a steel tower. According to Patent Document 1 below, a steel tower structure model is created from known information including a steel tower structure diagram to be measured, which has been captured in advance in a computer, and a reference is taken in a still image of the steel tower to be measured taken from the outside by a camera. The part made into the site | part is overlapped with the part used as the reference | standard site | part of the said steel tower structure model. When both reference parts coincide, the displacement amount of the still image tower displacement measurement target part is obtained with respect to the same part of the steel tower structure model, and the displacement of the measurement tower is measured from this displacement amount. .
JP 2003-148916 A

  However, for example, in the measurement using the above-described high-precision three-dimensional measuring instrument, in order to perform the measurement, an operator is used to measure each point and record the positional relationship of the measurement points in a record table called a field book. It is necessary to engage for a long time, and specialized techniques are required for the operation of the measuring equipment. Moreover, this measuring instrument is quite heavy, and it takes a lot of time to go to the high-voltage tower that is built in a relatively severe place to carry people such as mountainous areas. To do. In addition, since the data obtained by measurement cannot be confirmed on the spot, it will be confirmed by taking it home. However, if it is discovered that there is an error or oversight in the measurement, the measurement must be performed again. In other words, this point was a factor that caused mental anxiety and stress to the measurer.

  In addition, the measurement results are written in the above-mentioned field book or summarized in a table format. However, it is often the case that only numerical values such as measured values are listed, and even an expert can intuitively determine the amount of displacement. It is not easy to figure out.

  In the invention disclosed in Patent Document 1 described above, the camera is photographed from the outside of the steel tower. However, the steel tower is usually surrounded by a high fence in a city area to ensure safety. In the mountainous areas where many steel towers are built, the topography and trees become obstacles, so as a real problem, take pictures with the camera from the outside of the steel tower. Difficult to do.

  The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to easily and reliably measure the displacement of a high-pressure tower by using a technique of three-dimensional photographic measurement, and to obtain acquired information. It is to provide a displacement measuring method of a high-pressure tower that can intuitively recognize the displacement from.

  According to an embodiment of the present invention, in the displacement measurement method for a high-voltage tower, a step of inputting photographic image data based on a plurality of photographs, and acquiring three-dimensional coordinates for each photograph based on the inputted photographic image data A three-dimensional measurement method comprising: a step of identifying a position to be performed; a step of associating a position for each photograph of the identified same point; and a step of obtaining a three-dimensional coordinate based on the position of the associated same point And using the camera to photograph the identified identical point from at least two different points inside the high-pressure tower surrounded by four legs, and the three-dimensional obtained by the three-dimensional measurement method A display step for performing a three-dimensional display based on the coordinates.

  According to the present invention, the displacement measurement of the high-voltage tower can be easily and reliably performed and the displacement can be intuitively recognized from the acquired information by using the technology of the three-dimensional photo measurement. A method can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in the flowchart of FIG. 1, the displacement measuring method of the high-voltage tower according to the embodiment of the present invention is a step of photographing the measurement object (ST1), which is a step of photographing the high-pressure tower that is the object of measurement. 3D image measurement processing (ST2), which is a step for obtaining the three-dimensional coordinates of the portion of the target reflective seal affixed to the high-voltage steel tower, and three-dimensional display based on the obtained three-dimensional coordinates. It can be roughly divided into three-dimensional display (ST3) of measurement data. Hereinafter, each step will be described.

(First step)
In the embodiment of the present invention, in order to perform the three-dimensional display in step 3, the high-pressure tower, which is a measurement object, is measured using a technique called three-dimensional photometry. This three-dimensional photo measurement is a method of measuring a measurement object by photographing the measurement object from a plurality of different directions and analyzing the photographed photograph data. By using this measurement method, it is possible to obtain physical quantity and quality information of the measurement object shown in the photograph.

  The “physical quantity” here refers to the position, length, and area of the measurement object shown in the photograph, and is a three-dimensional coordinate representing the spatial position. On the other hand, “quality information” is information for reading the purpose of use, the nature, etc. of the measurement object shown in the photograph. In the three-dimensional photo measurement in the present embodiment, the measurement object is clear and only the physical quantity is obtained.

  As shown in FIG. 2, the principle of 3D photo measurement acquires information on the shape of the measurement target c from the geometric relationship between the image b projected on the light receiving element surface a and the measurement target c. That's it. In this principle, the collinear condition that the three points of the measurement object c, the center d of the lens, and the image b on the light receiving element surface a are on the same straight line is used. However, it is impossible to acquire three-dimensional information including the depth of the measurement object from a photograph taken by one camera unless special conditions are given. Therefore, a stereo model is constructed from a set of two photographs taken from two different positions, and three-dimensional information is obtained by observing the measurement object.

  In actual photographing, first, a target reflection sticker 1 as shown in FIG. This target reflective seal 1 is made by acrylic coating the surface of aluminum and reflects incident light in all directions. The place to be affixed is a predetermined place in the measurement object, for example, a place as shown in FIGS. 4 and 5 in the high-pressure tower. FIG. 4 is a view showing the entire portion of the leg constituting the high-pressure tower in contact with the ground, and FIG. 5 is an enlarged view thereof. As shown in FIG. 5, the target reflective seal 1 shown in FIG. 3 is affixed to the head portion of the bolt at the base of the leg. In addition, the target reflective seal | sticker 1 stuck is about several dozen to about 200 places per high voltage | pressure tower.

  After the target reflection seal 1 is attached to the measurement object, the high-pressure tower is photographed. In the following description, a case will be described as an example in which a digital camera having an imaging screen size comparable to a normal 35 mm film camera and a lens having a focal length of 14 mm are used in combination.

  FIG. 6A is a plan view of the high-pressure tower T viewed from above. Here, the high-pressure tower T is represented by a square line, and a portion where the four corner lines intersect is a portion where the four legs of the high-pressure tower T are provided. In taking a picture, the camera C is held on the inside I of the four legs of the high-voltage tower T. Usually, as described above, there are obstacles in shooting around most of the high-voltage towers, so it is difficult to take a picture from the outside of the high-pressure tower as a real problem, so the inside of the four legs Shoot from I. As a result, it is possible to avoid a situation where photographing cannot be performed and measurement is impossible. The camera C uses the super-wide-angle lens as described above so that an object within a range surrounded by the line Ca, the camera C, the line Cb, and the inner side I is captured. By using the camera C equipped with such a lens, the three legs excluding the legs behind the place where the camera C is held can be accommodated in the photograph. This is because the accuracy of measurement can be improved by increasing the number of measurement points that overlap between photographs while suppressing the increase in the number of shots due to the principle of 3D photo measurement.

  When shooting, the strobes S1 to S3 that emit light in synchronization with the camera C are used on the inner side I. This is because the target reflection seal 1 affixed to the high-voltage steel tower T is clearly reflected so that the affixing position of the target reflection seal 1 reflected in the camera C can be made clearer. When taking a picture, an object having a reference length required at the time of 3D photo measurement processing, such as a reference scale, is also taken at the same time.

  Shooting from four directions with each leg on the back with such equipment position and configuration. Furthermore, as shown in FIG. 6 (b) when the high-pressure tower is viewed from the side, in order to increase the accuracy in the height direction, the height is divided into two steps in each direction. And in the displacement measuring method of the high-voltage tower in this Embodiment, only the lower layer part of a high-pressure tower is made into the object of measurement. This is because the structure of the steel tower takes into account the property that the displacement of the lower layer is erased in the upper layer. As a result, a total of 8 photographs are taken for each measurement object, and there are 6 photographs of each leg.

  The position of the camera C does not need to be determined accurately. This is because, as will be described later, by analyzing the data of the photographed image, the exact photographing position by the camera C can be determined conversely. In particular, by using the camera C as a digital camera, it is possible to check a photograph taken immediately after taking a picture. As a result, it is possible to eliminate the mental anxiety of the measurer that the measurement must be performed again if there is an error or oversight in the measurement after taking back and confirming the captured image data.

  Further, in the present embodiment, a case has been described in which the above-described camera and lens combination is used for shooting from the above-described shooting position in order to determine a more accurate three-dimensional coordinate value. If the same point specified from at least two different points is shot with a digital camera, the selection of the shooting position and equipment is particularly free.

(Second step)
When the imaging of the measurement object in the first step is completed, the process proceeds to a step of obtaining the three-dimensional coordinates of the portion of the target reflection seal 1 attached to the imaged high-pressure pylon (ST2).

  The three-dimensional image measurement process is performed as shown in the flowchart of FIG. The following processing is performed via software stored in advance on a CD-R or the like, and in the present embodiment, it is installed and used in the information processing apparatus at the time of use. As this information processing apparatus, for example, a personal computer or the like can be used. This software may be stored in advance in the information processing apparatus.

  First, photographic image data of the high-voltage tower T, which is a measurement object photographed by the camera C, is input to the information processing apparatus (ST21). This photographic image data is the basic data for three-dimensional display. Further, in this step 21, basic information of the camera C used for photographing, for example, the focal length of the lens, etc. is also inputted at the same time.

  Next, the feature point of the captured image is marked (ST22). This is performed in order to determine the position in order to obtain the three-dimensional coordinates necessary for performing the three-dimensional display. Here, the “feature point” refers to a target reflective seal that is affixed to a so-called required three-dimensional coordinate portion in the present embodiment. That is, in order to obtain three-dimensional coordinates, a flash is used for photographing and the target reflective seal 1 is reflected. As a result, the target reflective sticker 1 becomes the portion with the largest light quantity in the photographed image, and the target reflective sticker 1 is sequentially detected using this large light quantity as a clue, and a marking point is placed at the center point. Simultaneously with the installation of this marking point, each marking point is numbered in order from a certain reference point. This marking point is set for all target reflective seals 1.

  The three-dimensional coordinate data obtained by three-dimensional photometry is data showing the relative positional relationship that is valid only in the data group. In order to clarify the displacement of the high-pressure tower at different points in time, Conversion to unified coordinate space data is required. In step 23, information necessary for developing data in a unified coordinate space is input.

  The input of this information does not exist on the same line when there is past high-precision laser measuring instrument recorded in the information processing apparatus or three-dimensional coordinate data measured by a method such as three-dimensional photo measurement. This is automatically performed by the information processing apparatus on the assumption that the three-dimensional coordinate value of the measurement point does not change from the past measurement time. This information is used because it is practical and easy to use.

  If the three-dimensional coordinate values of the three measurement points to which the coordinate information is input are shifted due to displacement or the like, distortion may appear in the whole in the case of three-dimensional display. It can be easily determined that the three designated measurement points are shifted. However, if this distortion cannot be overlooked, the information is not input by the above-described method, but three points that are not affected by the displacement are selected again, or, for example, two measurement points on the X axis are selected. Enter the actual size value (distance) and the direction of the Y axis or Z axis perpendicular to the X axis. In the latter case, the direction of the remaining one axis is automatically determined.

  Next, automatic corresponding point processing is performed (ST24). As described above, in the photography in the present embodiment, a total of 8 pictures are taken for each measurement object, and each leg is shown in 6 pictures. Accordingly, six target reflection stickers 1 indicating the same point are also photographed. For this reason, it is not possible to determine which of the marking points of each photographic image is the same measurement point by simply installing the marking point in step 22. Therefore, in order to determine marking points that point to the same measurement point in each photographic image, it is necessary to associate the marking points between the photographic images with each other. For this reason, the marking points between the photographic images are associated with each other using the number assigned to each marking point in step 22.

  After the marking points between the photographic images are associated, a three-dimensional analysis process is performed using the associated data (ST25). This step is a step for collecting data as six pieces of data for photographic image data for the measurement points that are essentially the same in the present embodiment. By this three-dimensional analysis process, three-dimensional coordinates for each marking point can be obtained. At the same time, the position coordinates and orientation information of the camera C that took the picture are calculated, and the distortion of the lens of the camera C used for the photography is also corrected. Thereby, more accurate three-dimensional coordinates can be obtained.

  When this three-dimensional coordinate is obtained, it is output as an analysis result (ST26). For example, when a high-pressure tower constructed based on the obtained three-dimensional coordinates is displayed on the information processing apparatus, it can be displayed as a three-dimensional model M as shown in FIG. In FIG. 8, four position coordinates C ′ of the camera C are shown in the three-dimensional model M. An example in which the calculated three-dimensional coordinate data is displayed on the screen in a text format is shown as a display example 10 in FIG. In this display example 10, a title bar 11 is provided at the top. And on the screen 12 located below, Id13, name 14, and calculated three-dimensional coordinate data 15 are displayed from the left. The Id 13 and the name 14 are given to each marking point, thereby identifying each marking point. The three-dimensional coordinate data 15 indicates values of the X axis, the Y axis, and the Z axis from the left, respectively. These values indicate how far the three-dimensional coordinates are away from the reference point. Note that a plurality of data not shown on the screen 12 can be viewed by moving the scroll bar 16 up and down.

(Third step)
Next, a three-dimensional display step (ST3) of measurement data for performing three-dimensional display based on the obtained three-dimensional coordinates is performed.

  In this step, first, the three-dimensional coordinate data obtained in ST2 is input to the information processing apparatus (ST31). Next, coordinate data to be displayed in 3D is selected from the input 3D coordinate data, and various settings are made (ST32). The settings include, for example, the line thickness and color for displaying the reconstructed image based on the input coordinate data, and the amount of movement when operating a mouse or keyboard (hereinafter referred to as “mouse etc.”). . Further, rearrangement of the coordinate data is performed at the same time in order to obtain the member length of the display member. It should be noted that it is necessary to set the operation amount when operating the mouse or the like in the three-dimensional display step in the present embodiment by operating the mouse or the like to horizontally display the reconstructed image displayed. This is because it has functions for vertical and rotational movement, and enlargement or reduction. Here, the reconstructed image refers to an image reconstructed in this step using the three-dimensional coordinates used to configure the above-described three-dimensional model M.

  In the three-dimensional display step in this embodiment, a plurality of three-dimensional coordinate data can be displayed in an overlapping manner. Therefore, it is possible to select whether or not to display a plurality of three-dimensional coordinate data in an overlapping manner (ST33). Here, “plurality” does not mean a plurality of high-pressure towers, but refers to the same high-pressure tower and that there is a time difference between the obtained three-dimensional coordinate data.

  When selection is made so that a plurality of three-dimensional coordinate data is not displayed in an overlapping manner (N in ST33), a reconstructed image based on one three-dimensional coordinate data is displayed (ST34). FIG. 11 shows an example of a screen on which the reconstructed image is displayed as a schematic diagram. The alphabets A to D displayed at the bottom of each of the four legs of the high-pressure tower are for determining the positional relationship of the high-pressure tower when performing display.

  On the other hand, when selection is made to display a plurality of three-dimensional coordinate data in an overlapping manner (Y in ST33), first, matching processing of corresponding measurement points of the plurality of three-dimensional coordinate data selected to be displayed is performed (ST35). ). The advantage of displaying multiple 3D coordinate data in a superimposed manner is that, for example, new 3D coordinate data compared to the reference data, such as comparison with design data and comparison of displacement of members that occur over time, etc. It is that it is possible to easily understand visually how much displacement has been shown. For this purpose, the marking points of the reference data and the other three-dimensional coordinate data must correspond to each other on the three-dimensional coordinates. Further, the reference point of the reference data is matched with the reference point in the other three-dimensional coordinate data (ST36). For example, even if the marking points of a plurality of individual three-dimensional coordinate data displayed correspond to each other, the amount of displacement cannot be grasped if the reference point is shifted. By performing these matching processes (correspondence), how much the image is reconstructed by comparing the image reconstructed based on the reference data with the reconstructed image based on other three-dimensional coordinate data, etc. Become able to understand.

  When these processes are completed, a plurality of three-dimensional coordinate data are displayed in an overlapping manner (ST37). FIG. 12 shows an example in which a plurality of three-dimensional coordinate data are displayed in an overlapping manner. In FIG. 12, the solid line is an image reconstructed based on the reference data. On the other hand, an image reconstructed based on other three-dimensional coordinate data is displayed with a dotted line. In this case, since both images are displayed on the basis of the leg A, all the data in the leg A portion match. In general, the displacement width (deviation value) is very small compared to the size of the high-pressure tower. Therefore, for example, the displacement is exaggerated by 30 times so that the side becomes clearer. Also in FIG. 12, an exaggerated display is made.

  Furthermore, for example, it is possible to determine the degree of risk, for example, by taking the difference at the measurement point that has been subjected to matching processing between the reference data and other three-dimensional coordinate data (ST38). This is done by determining a threshold value for the difference in advance and determining in which range the difference value of the displaced portion is in relation to the threshold value.

  In this way, by displaying a plurality of three-dimensional coordinate data in an overlapping manner, it is possible to easily recognize how much displacement is intuitively through vision. Further, when a three-dimensional display is performed based on a measurement error, a visually strange high-pressure tower is constructed and displayed, so that a measurement error can be easily found.

It is a flowchart which shows the displacement measuring method of the high voltage | pressure tower which concerns on embodiment of this invention. It is a schematic diagram explaining the principle of a three-dimensional photograph measurement. It is a schematic diagram which shows a target reflective seal | sticker. It is a schematic diagram of the leg part of a high voltage | pressure tower tower which shows the place which stuck the target reflective seal | sticker. It is the schematic diagram which expanded FIG. 4 in order to show the sticking state of a target reflective seal | sticker. It is a figure for demonstrating the method to image | photograph from the inside of a high voltage | pressure tower, (a) is a top view, (b) is a side view. It is a flowchart which shows the processing step of a three-dimensional image measurement in detail. It is a figure showing a three-dimensional model. It is a schematic diagram which shows the output three-dimensional coordinate data. It is a flowchart which shows the flow of the three-dimensional display of measurement data. It is a figure which shows the reconstruction image displayed from single three-dimensional coordinate data. It is a figure which shows the some reconstructed image displayed from the some three-dimensional coordinate data.

Explanation of symbols

a light-receiving element surface b image of light-receiving element surface c target object d lens center C camera I inside high-pressure tower S strobe T high-pressure tower 1 target reflection seal 10 display example

Claims (4)

Inputting photographic image data based on a plurality of photos;
Identifying a position for obtaining three-dimensional coordinates for each photo based on the inputted photo image data;
Associating a location for each photo about the identified same point;
Obtaining a three-dimensional coordinate based on the position of the associated same point, and a three-dimensional measurement method comprising:
Photographing the identified same point from at least two different points inside a high-pressure tower surrounded by four legs using a camera;
A display step for performing a three-dimensional display based on the three-dimensional coordinates obtained by the three-dimensional measurement method;
A displacement measuring method for a high-pressure tower, comprising:   In the photographing step, the inside of the high-voltage pylon surrounded by four legs, with one of the legs facing the back, facing the inside of the high-voltage pylon, and the other three legs being photographed. The high-pressure tower displacement measuring method according to claim 1, wherein the step is a photographing step of photographing each of the legs from four directions using a camera arranged in a high-speed tower.   The display step includes a first three-dimensional display displayed on the basis of the three-dimensional coordinates, and a three-dimensional coordinate of the same high-pressure pylon and is photographed before and after the photographing step. The high-pressure tower displacement measurement method according to claim 1 or 2, wherein a second three-dimensional display based on the three-dimensional coordinates obtained from the data is displayed simultaneously.   The method for measuring a displacement of a high-pressure tower according to any one of claims 1 to 3, wherein in the photographing step, photographing is performed by changing a plurality of heights from the ground.

Images