Overhead wire position measurement device and overhead wire position measurement method

Abstract

To provide an overhead wire position measurement device and an overhead wire position measurement method that can accurately obtain an overhead wire position with a simple configuration by using information on the shape of a rigid metal fitting.SOLUTION: An overhead wire position measurement device comprises: a first line sensor camera 9 that picks up images of an overhead wire and a rigid metal fitting; and an image processing apparatus 13 that processes the images picked up by the first line sensor camera 9. The image processing apparatus 13 comprises a rigid body detection unit 17 that detects the feature point coordinates of the rigid metal fitting from the image picked up by the first line sensor camera 9, and an overhead wire position calculation unit 19 that calculates the overhead wire position from the feature point coordinates detected by the rigid body detection unit 17.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an overhead line position measuring device and an overhead line position measuring method. [Background technology]

[0002] Generally, overhead wires that supply power to electric railway vehicles come into contact with current collectors every time a vehicle passes. As a result, the overhead wires gradually wear down and eventually break during operation. Therefore, a wear limit is set for the overhead wires, and stable operation of electric railway vehicles is maintained by replacing the overhead wires based on this wear limit. Conventional methods for measuring the wear state of overhead wires include directly measuring the wire thickness and measuring the width of the worn portion of the wire and converting the width into the thickness of the contact wire. In recent years, non-contact methods have been attempted, in which the width of the worn portion of the wire is determined by processing images from a line sensor camera and then converted into the thickness of the wire.

[0003] To accurately measure wear on overhead contact wires without contact, it is necessary to detect wear in the thickness direction of the wire, rather than just the width of the worn part. In particular, for overhead contact wires with a rectangular cross section rather than a circular one, the width of the worn part does not change due to wear, so it is necessary to detect wear in the thickness direction of the wire without contact. As a prerequisite for accurate measurement, it is necessary to accurately measure the position of the overhead contact wire, including the width and thickness directions of the wire.

[0004] Patent Document 1 discloses that a marker attached to a pantograph is captured using a single line sensor camera installed in a vertical direction, and the height of the pantograph (≒height of the overhead line) is measured using a pre-calculated coefficient. Patent Document 2 discloses that the position of the overhead line is measured using a single range laser. Patent Document 3 discloses that the position of the overhead line is measured by stereo measurement using two line sensor cameras. Patent Document 4 discloses that the position of the deviation is also measured by wear measurement using a single line camera. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2020-144049 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-146220 [Patent Document 3] Japanese Patent Application Laid-Open No. 2017-9446 [Patent Document 4] Japanese Patent Application Laid-Open No. 2007-271445 [Patent Document 5] Patent No. 6641729 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the device described in Patent Document 1 can obtain information about the overhead wire's height, but does not consider information about the overhead wire's width. The device described in Patent Document 2 may not be able to obtain accurate information about the overhead wire's position in both the width and height directions due to the trade-off between imaging frequency and accuracy, which is a characteristic of range lasers. The device described in Patent Document 3 requires the optical axes of two line sensor cameras to be aligned for stereo measurement, which may complicate the work and system required. The device described in Patent Document 4 requires an additional system to obtain information about the height.

[0007] The present invention has been made in consideration of the above-mentioned circumstances, and the problem that the present invention aims to solve is to provide an overhead line position measuring device and an overhead line position measuring method that can accurately obtain the overhead line position with a simple configuration using shape information of rigid metal fittings. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention employs the following means. That is, the overhead line position measuring device of the present invention comprises a first line sensor camera that captures images of an overhead line and a rigid metal fitting, and an image processing device that processes images from the first line sensor camera, and the image processing device comprises a rigid body detection unit that detects feature point coordinates of the rigid metal fitting from the images from the first line sensor camera, and an overhead line position calculation unit that calculates the overhead line position from the feature point coordinates detected by the rigid body detection unit.

[0009] In the overhead line position measuring device of the present invention, characteristic points of rigid metal fittings are detected from the image of the first line sensor camera, and the overhead line position is calculated from the coordinates of these characteristic points, so that the overhead line position can be obtained with high accuracy using a simple configuration.

[0010] In one aspect of the present invention, the overhead line position calculation unit calculates the overhead line position from the feature point coordinates of two points. In this embodiment, the overhead line position is calculated from the coordinates of two feature points, so that the overhead line position can be obtained with fewer steps.

[0011] In one aspect of the present invention, the system further includes a second line sensor camera that is installed at a position different from that of the first line sensor camera and captures images of the overhead wire and the rigid metal fittings. In this embodiment, images of the overhead line and the rigid metal fittings are additionally obtained by the second line sensor camera, so that the number of feature points that can be used for calculation is increased, thereby improving the accuracy of the overhead line position calculation.

[0012] The overhead line position measuring method of the present invention includes capturing an image of an overhead line and a rigid metal fitting with a first line sensor camera, detecting feature point coordinates of the rigid metal fitting from the captured image, and calculating the overhead line position from the feature point coordinates. In the overhead line position measuring method of the present invention, characteristic points of rigid metal fittings are detected from the image of the first line sensor camera, and the overhead line position is calculated from the coordinates of these characteristic points, so that the overhead line position can be obtained with high accuracy using a simple configuration.

[0013] In one aspect of the present invention, the calculation of the overhead line position includes calculating the overhead line position from the feature point coordinates of two points. In this embodiment, the overhead line position is calculated from the coordinates of two feature points, so that the overhead line position can be obtained with fewer steps.

[0014] In one aspect of the present invention, the method includes capturing images of the overhead wire and the rigid metal fittings with a second line sensor camera positioned differently from the first line sensor camera. In this embodiment, images of the overhead line and the rigid metal fittings are additionally obtained by the second line sensor camera, so that the number of feature points that can be used for calculation is increased, thereby improving the accuracy of the overhead line position calculation. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide an overhead contact line position measuring device and an overhead contact line position measuring method that can obtain the overhead contact line position with high accuracy using shape information of rigid metal fittings with a simple configuration. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is an explanatory diagram showing an example of installation of an overhead line position measuring device according to an embodiment of the present invention; [Figure 2] 1 is an explanatory diagram showing an example of installation of an overhead line position measuring device according to an embodiment of the present invention; [Figure 3] 1 is a block diagram showing a configuration of an overhead wire position measuring device according to an embodiment of the present invention. [Figure 4] 3 is a flowchart illustrating an operation of the overhead line position measuring device according to the embodiment of the present invention. [Figure 5] 1 is an explanatory diagram comparing an image captured by a line sensor camera of an overhead contact line position measuring device according to an embodiment of the present invention with a rigid metal fitting and an overhead contact line; [Figure 6] 1 is an explanatory diagram showing an example of installation of an overhead line position measuring device according to an embodiment of the present invention; [Figure 7] 1 is an explanatory diagram showing an example of installation of an overhead line position measuring device according to an embodiment of the present invention; [Figure 8] 1 is an explanatory diagram showing an example of installation of an overhead line position measuring device according to an embodiment of the present invention; [Figure 9] 1 is a block diagram showing a configuration of an overhead wire position measuring device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. (First embodiment) 1, 2, and 6 are explanatory diagrams showing installation examples of an overhead contact line position measuring device according to an embodiment of the present invention. As shown in FIG. 1, the overhead contact line position measuring device 1 according to this embodiment includes a first line sensor camera 9 that captures images of the overhead contact line 7 and the rigid metal fittings 5, a lighting device 11 that illuminates the overhead contact line 7 and the rigid metal fittings 5, and an image processing device 13 that processes images captured by the first line sensor camera 9. As shown in FIG. 2, the first line sensor camera 9 and the lighting device 11 are installed on the roof of the vehicle 3, and the image processing device 13 is installed inside the vehicle 3 and is connected to the first line sensor camera 9 by wire or wirelessly. As shown in FIG. 6, the first line sensor camera 9 is installed with its optical axis facing diagonally upward toward the sleepers on the roof of the vehicle so that the joints of the overhead contact line 7 and the upper and lower parts of the rigid metal fittings 5 ​​can be seen.

[0018] FIG. 3 is a block diagram showing the configuration of the overhead wire position measuring device 1. As shown in FIG. 3, the image processing device 13 includes an image input unit 15, a rigid body detection unit 17, an overhead wire position calculation unit 19, and a storage unit 21. The image input unit 15 receives an image from the first line sensor camera 9 and sends the image data to the storage unit 21, where it is stored as a line sensor image. The rigid body detection unit 17 retrieves data necessary for rigid body detection, including the line sensor image and preset camera parameters, from the storage unit 21, and detects feature point coordinates of the rigid fittings 5 ​​from the line sensor image of the first line sensor camera 9. The detected feature point coordinates are sent to the storage unit 21 and stored therein. The overhead wire position calculation unit 19 retrieves data necessary for calculation of the feature point coordinates, preset rigid body parameters of the rigid fittings 5, camera parameters, etc. from the storage unit 21, and calculates the overhead wire position from the feature point coordinates detected by the rigid body detection unit 17. The calculated overhead wire position is sent to the storage unit 21 and stored therein.

[0019] The image processing device 13 is an information processing device such as a personal computer. The image input unit 15, the rigid body detection unit 17, and the overhead line position calculation unit 19 may be software or programs executed by the CPU or GPU of this information processing device. The storage unit 21 may be a storage device such as a hard disk or flash memory provided inside or outside this information processing device. The image processing device 13 is functionally provided with the configuration shown above by the information processing device executing processing based on a preset program or the like.

[0020] 4 is a flowchart illustrating the operation of the overhead line position measuring device 1 of this embodiment. The operation of the overhead line position measuring device 1 configured as described above will be described with reference to this flowchart. When the operation starts (S000), processing of the number of images captured by the first line sensor camera 9 is started (S001). The image input unit 15 captures images from the first line sensor camera 9, and the line sensor images (S0003) are sent to the rigid body detection unit 17.

[0021] The process performed by the rigid body detection unit 17 is a process of detecting the rigid fitting 5 from the line sensor image. FIG. 5 is a diagram showing an image G of the rigid fitting 5 and the overhead wire 7 captured by the first line sensor camera 9, and a comparison between the rigid fitting 5 and the overhead wire 7. In detecting the rigid fitting 5, a template image of the rigid fitting 5 is prepared in advance, and the rigid fitting 5 portion is identified. At this time, as shown in FIG. 5, the coordinates of the feature points of the rigid fitting 5 required by the overhead wire position calculation unit 19 are detected by edge detection processing with reference to the coordinates of the template. In this embodiment, T1, T2, and T3 shown in FIG. 5 are detected as feature points (S004). The coordinates of the detected feature points T1, T2, and T3 of the rigid fitting 5 (S005) are sent to the overhead wire position detection unit 19.

[0022] The process performed by the overhead line position calculation unit 19 is to calculate the overhead line position from the coordinates (S005) of the characteristic points T1, T2, and T3 of the rigid metal fitting 5 detected by the rigid body detection unit 17 and the shape information (drawing information) of the rigid metal fitting 5 (S006). Here, the overhead line position is calculated using the method described in Patent Document 5. The following [Equation 1] is the formula used in this calculation.

[0023]

number

[0024] Here, s is a scaling coefficient, f is the focal length of the first line sensor camera 9, c is the principal point coordinate, u is the position of the captured image in the image coordinate system of the first line sensor camera 9, and X and Y are the positions in the coordinate system of the rigid metal fitting 5. Here, the translation vector (t1, t2) and rotation angle θ, which will be described later, are initially unknown parameters, and the other parameters are known parameters.

[0025] FIG. 6 is an explanatory diagram showing the positional relationship between the image coordinate system (u, w) of the first line sensor camera 9 of the overhead line position measurement device 1 and the coordinate system (X, Y) of the rigid metal fitting 5. The image processing device 13 is omitted from FIG. 6. As shown in FIG. 6, the coordinate position of each part of the rigid metal fitting 5 is expressed by the (X, Y) coordinate system, and the image position of the first line sensor camera 9 is expressed by the (u, w) coordinate system. In FIG. 6, captured pixels are projected onto the captured image S located at a distance 1. Here, in [Equation 1], (t1, t2) is the translation vector from the origin of the rigid metal fitting 5 (X, Y) to the origin of the camera's image coordinate system (u, w), and θ is the rotation angle when converting from the rigid metal fitting 5 (X, Y) to the image coordinate system (u, w).

[0026] As mentioned above, in [Equation 1], the unknown parameters are the translation vector (t1, t2) and the rotation angle θ of the coordinate transformation. Therefore, these unknown parameters can be calculated by formulating three simultaneous equations. Therefore, as shown in FIG. 6, these unknown parameters can be calculated by substituting the pixel data u1, u2, and u3 of the feature points T1, T2, and T3 of the rigid metal fitting 5 into [Equation 1] and solving the simultaneous equations. The (X, Y) coordinates of the feature points T1, T2, and T3 are known from the drawing information used when creating the rigid metal fitting 5. As disclosed in Patent Document 5, camera parameters and lens distortion coefficients can be determined in advance by camera calibration. Substituting the calculated unknown parameters into [Equation 1] determines the positions (S007) of both ends M1 and M2 of the wear surface F of the overhead line 7 shown in FIG. 5 on the coordinate system (X, Y) of the rigid metal fitting 5, making it possible to calculate the extent of wear. If the next image data is in the storage unit 21 (S008), the process is repeated from S001. If all the image data has been processed, the series of processes ends (S009).

[0027] As described above, in this embodiment, the coordinates of the feature points of the rigid fitting 5 are detected from images of the rigid fitting 5 and the overhead wire 7 captured by the first line sensor camera 9. The unknown parameters necessary for calculating the overhead wire position, the translation vector (t1, t2) and the rotation angle θ of the coordinate transformation, are found from the shape information of the rigid fitting 5 by solving simultaneous equations. These parameters are then used to calculate the position of the worn surface of the overhead wire, thereby detecting the state of wear. Therefore, it is possible to provide an overhead wire position measuring device and an overhead wire position measuring method that can accurately determine the overhead wire position using the shape information of the rigid fitting 5 with a simple configuration. While this embodiment illustrates an overhead wire with a circular cross section, it may also be rectangular. When the cross section of the overhead wire is rectangular, the width of the worn portion does not change depending on the degree of wear, making it difficult to detect the state of wear using conventional methods that detect wear based on the width of the worn portion. However, in this embodiment, the position of the worn portion of the overhead wire is calculated in the coordinate system (X, Y) of the rigid fitting, making it easy to detect the state of wear of the overhead wire even if the cross section of the overhead wire is rectangular. The device can be made smaller thanks to the simple configuration of the first line sensor camera 9 and image processing device 13. In addition, the wear state can be detected if the coordinates of three feature points and one point on the wear surface can be calculated, so the number of measurement points is small, and therefore measurements can be made at high frequencies.

[0028] (Second embodiment) FIG. 7 is an explanatory diagram showing the positional relationship between the image coordinate system (u, w) of the first line sensor camera 9 and the coordinate system (X, Y) of the rigid metal fitting 5 of the overhead line position measurement device 1 of this embodiment. The image processing device 13 is omitted from FIG. 7 . The overhead line position measurement device 1 of this embodiment has the same configuration as that of the first embodiment. This embodiment differs from the first embodiment in that, as shown in FIG. 7 , the installation angle of the rigid metal fitting 5 is constrained to be perpendicular to the rail surface 25 and the ceiling 23 of the rigid section to which the rigid metal fitting 5 is fixed, thereby reducing the number of feature points of the rigid metal fitting 5 required for calculation from three points T1, T2, and T3 to two points T1 and T3. Specifically, the Y axis of the coordinate system of the rigid metal fitting 5 is perpendicular to the ceiling 23 and the rail surface 25. Therefore, in [Equation 1] of the first embodiment, θ is known, and the translation vector (t1, t2) can be obtained by substituting the two feature points T1 and T3 into [Equation 1] and solving the simultaneous equations. In this embodiment, in addition to the effects of the first embodiment, the number of feature points is reduced by one, thereby further increasing the speed, and since θ is known, it is possible to calculate the overhead line position while reducing the influence of disturbances.

[0029] (Third embodiment) FIG. 8 is a diagram illustrating an example of installation of an overhead wire position measurement device 10 according to this embodiment. This embodiment differs from the first embodiment in that a second line sensor camera 27 is installed at a different position from the first line sensor camera 9 and captures images of the overhead wire 7 and the rigid metal fittings 5. As shown in FIG. 8, the second line sensor camera 27 is installed at a different position from the first line sensor camera 9, with its optical axis directed diagonally upward in the direction of the sleepers on the roof of the vehicle 3 so that the joints of the overhead wire 7 and the upper and lower parts of the rigid metal fittings 5 ​​can be seen. In this embodiment, the first line sensor camera 9 and the second line sensor camera 27 are arranged on the left and right sides of the drawing, sandwiching the lighting device 11 in the direction of the sleepers. Although the image processing device 13 is omitted in FIG. 8, the image processing device 13 receives image data from both the first line sensor camera 9 and the second line sensor camera 27, as described below.

[0030] 9 is a block diagram of an overhead wire position measuring device 10 of this embodiment. Since the configuration and operation of the image processing device 13 are the same as those of the first embodiment, the same reference numerals are used for the respective blocks and detailed description will be omitted. This embodiment differs from the first embodiment in that the image input unit 15 receives image data from both the first line sensor camera 9 and the second line sensor camera 27. Subsequent processing is the same as that of the first embodiment, except for conversion of translation vectors and rotation angles of coordinate transformation, which will be described later.

[0031] As shown in Fig. 8, the coordinate system of the first line sensor camera 9 is represented by (u, w), the coordinate system of the second line sensor camera 27 is represented by (u', w'), and the respective translation vectors are represented by (t1, t2) and (t'1, t'2). Here, the first line sensor camera 9 and the second line sensor camera 27 are disposed at predetermined positions on the vehicle 3, so their relative relationship is known. In Fig. 8, the difference vector from the coordinate system (u, w) of the first line sensor camera 9 to the coordinate system (u', w') of the second line sensor camera 27 is represented by (dt1, dt2), and the differential rotation angle from the coordinate system (u, w) of the first line sensor camera 9 to the coordinate system (u', w') of the second line sensor camera 27 is represented by -dθ, which are known. Therefore, the translation vector (t'1, t'2) of the second line sensor camera 27 is expressed as the following [Equation 2] using the translation vector (t1, t2) of the first line sensor camera 9 and the difference vector dt1, dt2.

[0032]

number

[0033] Similarly, the rotation angle θ' from the coordinate system (X, Y) of the rigid metal fitting 5 to the coordinate system (u', w') of the second line sensor camera 27 is expressed as the rotation angle θ of the coordinate transformation of the first line sensor camera 9 and the aforementioned differential rotation angle -dθ, as shown in the following [Equation 3].

[0034]

number

[0035] When analyzing the image acquired by the second line sensor camera 27, by substituting [Equation 2] and [Equation 3] into [Equation 1], the unknowns are three variables: the translation vector (t1, t2) and the rotation angle θ, as in the first embodiment. Therefore, these unknowns can be determined if there are a total of three feature points of the rigid metal fitting 5 acquired by the first line sensor camera 9 and the second line sensor camera 27. The subsequent process of detecting the wear state of the overhead wire 7 is the same as in the first embodiment. Therefore, in this embodiment, it is possible to select feature points of the rigid metal fitting 5 acquired by the first line sensor camera 9 and the second line sensor camera 27 that are less affected by noise and perform processing. Therefore, in addition to the effects of the first embodiment, it is possible to select feature points with less noise from the many feature points acquired by the two cameras, thereby reducing the effects of external disturbances. Furthermore, wear can be measured by selecting or averaging images with less noise from the images acquired by the two cameras, thereby improving measurement accuracy. [Explanation of symbols]

[0036] 1, 10 Overhead line position measuring device 5 Rigid metal fittings 7. Overhead Lines 9. First line sensor camera 13 Image processing device 17 Rigid body detection unit 19. Overhead line position calculation unit 27 Second line sensor camera

Claims

1. a first line sensor camera that captures images of the overhead wire and the rigid metal fitting; an image processing device that processes an image from the first line sensor camera, The image processing device includes: a rigid body detection unit that detects feature point coordinates of the rigid metal fitting from an image captured by the first line sensor camera; an overhead contact line position calculation unit that calculates the overhead contact line position from the feature point coordinates detected by the rigid body detection unit; An overhead line position measuring device comprising:

2. The overhead line position measuring device according to claim 1 , wherein the overhead line position calculating unit calculates the overhead line position from the coordinates of two feature points.

3. 3. The overhead line position measuring device according to claim 1, further comprising: a second line sensor camera that is installed at a position different from that of the first line sensor camera and captures images of the overhead line and the rigid metal fittings.

4. capturing an image of the overhead wire and the rigid metal fitting with a first line sensor camera; detecting feature point coordinates of the rigid metal fitting from the captured image; calculating the overhead line position from the feature point coordinates.

5. The overhead line position measuring method according to claim 4, wherein the step of calculating the overhead line position comprises calculating the overhead line position from the coordinates of two feature points.

6. 6. The overhead line position measuring method according to claim 4, further comprising: capturing images of the overhead line and the rigid metal fittings with a second line sensor camera positioned differently from the first line sensor camera.

Images