Method for inspecting electric train line

Abstract

To provide a method capable of stably acquiring various information necessary for maintenance and management in a method for inspecting an overhead rigid electric train line using an optical cutting method.SOLUTION: An overhead rigid electric train line is formed by a conductive steel rail in a cross-sectional dumbbell shape obtained by connecting a leg part and a head part by a central constricted part, a top surface of the leg part is fixed, and an underside of the head part is a sliding surface, and in the electric train line, a luminous flux is irradiated to the sliding surface and a reference surface extending from the central constricted part toward an outward tip of the leg part, and the sliding surface and the reference surface irradiated with the luminous flux are optically photographed at constant intervals. Here, a process for performing image analysis of picked-up data composed of a plurality of frame images obtained along a direction of line extension includes an extraction step for extracting an image corresponding to an electric train line about each of the frame images, and a correction step for correcting each of the frame images from a series of luminance data of the frame images.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to an inspection method for dynamically inspecting overhead contact lines from on a running vehicle, and more particularly to an inspection method for overhead rigid contact lines using an optical section method. [Background technology]

[0002] One method for inspecting overhead contact lines installed above the tracks to transmit electrical energy to trains traveling on the tracks is the optical section method, in which a strip of light is projected onto the contact lines perpendicular to their longitudinal direction from above a vehicle traveling on the tracks, and the projected area is optically photographed. This dynamic inspection method allows image analysis of image data taken along the tracks to obtain various pieces of information necessary for the maintenance and management of the contact lines.

[0003] For example, Patent Document 1 discloses a method for measuring the cross-sectional shape of a trolley wire that is suspended on a track with its grooves clamped by fixtures, by arranging multiple laser light sources on a vehicle perpendicular to the track, selecting one laser light source to be turned on, and capturing an image of the trolley wire in the longitudinal direction using a light-section method. Image analysis of the captured image data identifies the positions of the grooves on the sides of the trolley wire as well as the center position of a virtual circle that includes an arc region, enabling the cross-sectional shape of the trolley wire to be measured with high accuracy.

[0004] Non-Patent Document 1 also describes a method for measuring sliding surface wear using an optical cutting method for overhead rigid contact lines used in subways and tunnel sections. Overhead rigid contact lines are primarily classified into two types: π-type and T-type contact lines, which grip the contact wire with a frame or ear, and conductive steel rails with a dumbbell-shaped cross section, connecting the foot and head at a central constriction. Unlike contact wires with a circular cross section, conductive steel rails do not change the width of the sliding surface even as the wear of the rectangular head increases, making it impossible to measure the cross-sectional shape. Therefore, the authors propose measuring the remaining height from the sliding surface to the top surface of the rail and using this as a wear evaluation index. Similarly, they also propose measuring the remaining height from the sliding surface to the lowest point on the underside of the contact wire gripper as a wear evaluation index for overhead rigid contact lines using contact wires. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2021-179369 [Non-patent literature]

[0006] [Non-Patent Document 1] Hiroaki Usuki, Shu Matsumura, Yusuke Taira, Kazutoshi Yamashita, Masatoshi Shimizu, "Abrasion Measurement Method for Rigid Conductor Wires Using Optical Cutting Method," Institute of Electrical Engineers of Japan Research Meeting Materials (Web) VT-22-010-019 / TER-22-065-074, Automobile Research Society / Transportation and Electric Railway Research Society, pp. 55-58, September 27, 2022 Summary of the Invention [Problem to be solved by the invention]

[0007] In Non-Patent Document 1, image analysis of a conductive steel rail with known dimensions involves correcting the position and angle of the conductive steel rail using an ICP algorithm, then detecting the lines between the sliding surface and the reference surface to estimate the position of the top surface of the conductive steel rail and determine the distance from the sliding surface as the remaining height. However, there are cases where the line of the reference surface, which is located behind the sliding surface along the light beam, cannot be detected due to, for example, insufficient light reflection caused by dirt on the reference surface or shadows cast by support points or connectors on the conductive steel rail. As a result, this method is insufficient for reliably obtaining various information necessary for maintenance and management.

[0008] The present invention has been made in view of the above circumstances, and its object is to provide a method for inspecting overhead rigid train lines using the optical sectioning method, which can stably obtain various information necessary for maintenance and management. [Means for solving the problem]

[0009] The overhead rigid contact line inspection method of the present invention is an overhead rigid contact line inspection method in which a strip-shaped light beam is irradiated onto the contact line perpendicular to its longitudinal direction from above a vehicle traveling on the track while optically photographing the irradiated area, wherein the contact line is an overhead rigid contact line made of conductive steel rails with a dumbbell-shaped cross section, with a foot section and a head section connected at a central waist section, the upper surface of the foot section being fixed and the lower surface of the head section being the sliding surface, and the method includes a process of irradiating the light beam onto the sliding surface and a reference surface extending from the central waist section toward the outer tip of the foot section, optically photographing the sliding surface and the reference surface irradiated with the light beam at regular intervals, and performing image analysis on the image data consisting of a plurality of frame images obtained along the extension direction of the track, the process comprising the steps of: extracting an image corresponding to the contact line for each of the frame images; and correcting each of the frame images from a series of brightness data of the frame images.

[0010] According to this feature, even when the reference plane cannot be directly detected, the reference plane can be identified by the correction process, and various information necessary for maintenance and management can be stably obtained.

[0011] In the above invention, the correction step may be characterized in that it acquires the longitudinal position and longitudinal width of the accessory of the electric rail from the change in the series of brightness data. According to this feature, even when the reference plane cannot be directly detected by the accessory, various information necessary for maintenance and management can be stably obtained from the acquired longitudinal position and longitudinal width of the accessory.

[0012] In the above-described invention, the correction step may be characterized in that, using a pair of images made up of the frame images corresponding to both sides of the longitudinal position and the longitudinal width, image correction is performed for each frame of the imaging data so that a second straight bright line corresponding to the reference surface is formed on both sides of a first straight bright line corresponding to the sliding surface. According to this feature, various information required for maintenance and management can be stably obtained by a relatively easy procedure.

[0013] In the above-described invention, a threshold value may be set in advance for the width in the longitudinal direction, and when the width in the longitudinal direction is larger than the threshold value, the second straight bright line is corrected using an external dividing point of the pair of images, and when the width in the longitudinal direction is smaller than the threshold value, the second straight bright line is corrected using an internal dividing point of the pair of images. According to this feature, various information required for maintenance and management can be stably obtained while performing the correction process relatively accurately.

[0014] In the above-described invention, the amount of wear of the sliding surface may be measured by comparing each of the frame images with a known cross-sectional shape of the electric rail. According to this feature, the amount of wear can be obtained as information necessary for maintenance and management through a relatively easy procedure. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a block diagram of an inspection device used in an inspection method for an overhead rigid contact line according to the present invention. FIG. [Figure 2] FIG. 1 is a cross-sectional view of an overhead rigid contact line. [Figure 3]10A and 10B are diagrams illustrating a method for measuring the amount of wear by superimposing a frame image and a template. [Figure 4] (a) A diagram of bright lines on a frame image in the normal case and (b) when the reference surface is shaded by an accessory part. [Figure 5] (a) A pseudo-image of a train line in which each bright spot on the frame image is projected onto the x-axis (moved up and down) and arranged in order along the y-axis, and (b) a series of graphs of brightness data (average brightness Is) obtained by averaging the brightness of all dots. [Figure 6] (a) Graph of the average brightness Is for each frame image, and the longitudinal positions and widths of (b) bolts, (c) support fittings, and (d) connecting fittings identified by the moving average filter, and (e) the equation for the moving average filter. [Figure 7] FIG. 10 is a pseudo-pictorial view showing an attachment frame and the frames immediately before and after it. [Figure 8] FIG. 10 is a diagram showing correction by interpolation of an emission line corresponding to a reference plane. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an inspection method for an overhead rigid contact line according to the present invention will be described with reference to FIGS.

[0017] First, the inspection device used in the inspection method will be described.

[0018] As shown in FIG. 1, the inspection device 1 is installed on a vehicle 10 (railroad vehicle) traveling on a track. The inspection device 1 includes a light irradiation unit 2 that irradiates a laser beam L onto electric wires 20 installed along the track on which the vehicle 10 travels, an imaging unit 3 that captures an image of the bright line formed by the laser beam L irradiated onto the electric wires 20, an irradiation control unit 4 that controls the lighting operation of the light irradiation unit 2, and an imaging control unit 5 that controls the timing of capturing images by the imaging unit 3. The light irradiation unit 2 and the imaging unit 3 are attached to a mounting base 11 installed on the ceiling 12 of the vehicle 10. Each of the other vehicles coupled to the vehicle 10 is equipped with a pantograph, and the contact strips of the current collector shoe are brought into contact with the underside of the electric wires 20 to supply power to the powered vehicle. The electric wires 20 are fitted with accessories such as bolts 15 that pass through them from side to side, support brackets 16 that are attached to the ceiling surface 19, and connecting brackets 17 that connect the electric wires 20 together in the longitudinal direction.

[0019] The light irradiation unit 2 is disposed so that the optical axis of the irradiated laser beam L faces vertically upward and so that the light irradiation unit 20 irradiates the electric train wire 20 with a band-like beam perpendicular to the longitudinal direction. In other words, the laser beam L is irradiated toward the electric train wire 20 from below along a vertical plane S perpendicular to the longitudinal direction of the electric train wire 20. This allows a bright line to be formed on part of the circumferential line of the electric train wire 20 that is along the vertical plane S. In other words, this bright line becomes part of the contour line of the electric train wire 20.

[0020] The imaging unit 3 is installed so as to optically image the irradiation area of the electric train wire 20 where the laser beam is irradiated. At this time, the imaging unit 3 is disposed diagonally below and in front of or behind the vertical plane S so that the bright line formed by the laser beam can be imaged as part of the contour line of the electric train wire 20. The imaging unit 3 is oriented so that the angle of view of the contour line of the electric train wire 20 in the vertical plane S is included. This makes it possible to image the contour line from the front or rear.

[0021] The illumination control unit 4 can control the turning on and off of the light irradiating unit 2 based on a signal from the imaging control unit 5. In other words, the illumination control unit 4 can control the light irradiating unit 2 to be turned on by a turn-on signal received from the imaging control unit 5, and to be turned off by a turn-off signal.

[0022] As described above, the imaging control unit 5 can send signals to the irradiation control unit 4 regarding the turning on and off of the light irradiation unit 2, and can also control the operation of the imaging unit 3. The captured images can be collected and stored in a storage device (not shown). Note that an image analysis device can be further installed in the imaging control unit 5, so that the collected images can be analyzed on board the vehicle.

[0023] Next, an inspection method using the inspection device 1 will be described.

[0024] This inspection method uses a light section method in which a strip-shaped light beam L is irradiated perpendicularly to the longitudinal direction onto the electric rail 20 from above a vehicle 10 running on the track, and the irradiated area is optically photographed.

[0025] First, while the vehicle 10 is traveling, the light irradiation unit 2 projects a laser beam L to irradiate the electric rail 20. That is, the imaging control unit 5 sends a turn-on signal to the irradiation control unit 4 to turn on the light irradiation unit 2. The laser beam L then forms a bright line on the electric rail 20 as part of its contour. The formed bright line is then imaged by the imaging unit 3, and the imaging control unit 5 stores the image in a storage device. This imaging is repeated at a predetermined frame rate corresponding to the traveling speed, obtaining a plurality of frame images taken at regular intervals along the direction in which the track extends.

[0026] As shown in Fig. 2, the target electric rail 20 here is an overhead rigid electric rail, a conductive steel rail with a roughly dumbbell-shaped cross section in which a foot section 21 and a head section 23 are connected at a central constricted section 22. This cross section is a plane perpendicular to the longitudinal direction of the electric rail 20 and substantially coincides with the above-mentioned vertical plane S. The upper surface of the foot section 21 of the electric rail 20 is fixed to a support bracket 16 (see Fig. 1) attached to a ceiling surface 19 above the track, and the lower surface of the head section 23 serves as a sliding surface with which the contact strip comes into contact. Furthermore, the reference surface 21a, which is the lower surface of the foot section 21, extends from the central constricted section 22 toward the outer tip of the foot section 21 and has an upward slope toward the left and right outer sides in the above-mentioned cross section.

[0027] As shown in FIG. 3(a), bright lines formed by irradiating the electric rail 20 having such a shape with a laser beam L from below are a straight bright line on the sliding surface formed on the underside of the head 23 and two diagonal straight bright lines on the left and right sides formed on the underside of the foot 21. That is, the frame image 20a obtained by imaging records a bright line B1 corresponding to the sliding surface and two left and right bright lines B2 and B3 corresponding to the reference surface 21a of the foot 21. By analyzing the frame image 20a and imaging data consisting of a plurality of such images stored in a storage device, various information necessary for the maintenance and management of the electric rail 20 can be obtained. One example of such information is the amount of wear on the head 23 of the electric rail 20.

[0028] As shown in Fig. 1(b), an analysis device (not shown) that performs image analysis of the captured image data stores in advance in an associated storage unit a known cross-sectional shape of the contact wire 20 before use (when new) as a template 20b. The analysis device can measure the amount of wear by comparing the frame image 20a with the template 20b.

[0029] As shown in FIG. 1C, in the image analysis, the analysis device extracts bright lines B2 and B3 formed on the reference surface 21a and bright line B1 formed on the sliding surface as an image corresponding to the electric rail 20 from the frame image 20a. At this time, taking into consideration that the imaging unit 3 captures an image of the electric rail 20 from diagonally below, the positions of each point on the extracted bright lines are corrected by, for example, keystone correction so that they correspond to the cross-sectional shape. Then, the frame image 20a and the template 20b are superimposed. At this time, the bright lines B2 and B3 of the frame image 20a are aligned with the positions of the reference surface 21a of the template 20b. Because the bright lines B2 and B3 are inclined relative to each other at a predetermined angle, the positions of the frame image 20a and the template 20b can be uniquely determined relative to each other.

[0030] Then, as shown in Fig. 1(d), the distance between the bright line B1 and the underside of the head 23 of the template 20b is measured and can be taken as the amount of wear. In this way, the amount of wear at the position on the sliding surface of the electric rail 20 where the frame image 20a was obtained can be measured.

[0031] As shown in FIG. 4, the overhead contact line 20 may be fitted with accessories such as the support bracket 16, as described above. This may cause the reference surface 21a to be shaded from the laser beam, preventing the formation of bright lines B2 and / or B3. For example, in FIG. 4(a), there is no shadow due to the accessories. On the frame image 20a, bright line B1, which corresponds to the sliding surface, and bright lines B2 and B3, which correspond to the reference surface 21a, are formed on both sides of the frame image 20a, allowing the wear amount to be measured as described above. On the other hand, in FIG. 4(b), a shadow is created by the accessories. Bright line B3 is not formed at the position corresponding to the reference surface 21a on the right side of the page, and bright line B4 is formed at the position corresponding to the surface of the accessories. In such a frame image 20a, the position where the template 20b should be superimposed cannot be identified using only one bright line B2 on the reference surface 21a, and the wear amount cannot be measured.

[0032] Therefore, as shown in Figure 5, accessory information is first obtained from the changes in a series of brightness data obtained by averaging the brightness for each frame image 20a. Because the frame images 20a are captured at regular intervals, the corresponding series of brightness data also contain positional information corresponding to these regular intervals. From the changes in this series of brightness data, accessory information, such as the longitudinal position and longitudinal width, is identified and acquired. Figure 5(a) shows pseudo images in which each bright spot in each frame image 20a in the captured data is projected onto the x-axis as if it were moved in the y-axis direction (up and down in Figure 4) to obtain an image extending in the x-axis direction (left and right in Figure 4) with a width of one dot. These pseudo images are arranged in the y-axis direction for each frame. Because the frame image 20a was captured by irradiating the laser beam L from directly below, this pseudo image is similar to an image captured from directly below the electric rail 20 using a line camera installed facing vertically upward. Bright lines representing the support points of the support fittings and the connection points of the connector fittings are observed, as shown in the figure. Also, Figure (b) shows the change in a series of brightness data when the brightness data (average brightness Is) for each frame image 20a, which is the average of the brightness of all dots (pixels) in each cross section, is arranged at a predetermined interval.

[0033] As shown in Figure 6, the longitudinal positions and longitudinal widths of three accessory parts, namely, bolts, support fittings, and connector fittings, are identified. First, as described above, the luminance values of the entire frame images 20a are averaged to obtain a luminance value, which is defined as the average luminance Is.

[0034] The average brightness Is is arranged in an order corresponding to the frame images 20a arranged at predetermined intervals in the y-axis direction to form the function Is(y) (see FIG. 1(e)). Then, for the function Is(y), moving average filters f1 and f2 are calculated. Here, the moving average filter is the average value in the y-axis direction of the average brightness Is from a negative position in the y-axis direction by width W1 or W2 as shown in FIG. 1(e). In other words, the average brightness of the entire frame image 20a changes depending on the accessory part, and the moving average filters f1 and f2 also change depending on the relationship between the width of the accessory part in the y-axis direction and widths W1 and W2.

[0035] For example, it is possible to imagine a situation in which the average luminance Is is higher when an accessory is present than when no accessory is present. It is sufficient to form a bright line that provides an average luminance value that is sufficient to compensate for the decrease in the bright line on the reference surface 21a due to blocking the reference surface 21a from the laser beam L. For example, this applies when a bright line is formed over a wide area within the field of view of the frame image 20a captured by the imaging unit 3, or when a bright line with high luminance is formed. The luminance of the bright line can change due to the reflection of the laser beam L toward the imaging unit 3 on the surface on which the bright line is formed. For example, a bright line with high luminance is likely to be formed on a flat surface directly facing the light irradiation unit 2 and the imaging unit 3, on a surface close to the imaging unit 3, when the optical path of the reflected light is short, or on a surface with high reflectivity. In such cases, if the width W is set wider than a certain value so that the area without accessories is included in the range up to the position in the y-axis direction minus the width W used to calculate the moving average filter, the average luminance Is in the area with the accessory will be higher, and the moving average filter will be relatively smaller than the average luminance Is in the area with the accessory. In other words, when the average brightness Is is greater than the moving average filter, it can be determined that an accessory part is present.

[0036] Here, when examining the average luminance Is in FIG. 1(a), it is found that the average luminance Is is low at the location of the bolt 15 or the connector 17 and high at the location of the support connector 16. The bolt 15 is a set of a bolt and a nut that penetrates the central constricted portion 22 from side to side, and the portion that blocks the laser beam L from the reference plane 21a is the side surface of a cylinder or polygonal prism with its axis in the left-right direction. Therefore, the laser beam L tends to disperse in the longitudinal direction of the vehicle 10, and the brightness of the bright line formed on the surface of the bolt 15 is low, and the area where the bright line is formed is also narrow. Therefore, the average luminance Is at the location of the bolt as an accessory is low. Furthermore, the connector 17 is a plate-like body that sandwiches the constricted portion 22 from the left and right, and the lower surface where the bright line is formed is located on the side of the plate-like body and is relatively narrow. As a result, the average luminance Is is also low at the location of the connector 17. Note that the connector 17 is relatively long along the longitudinal direction of the electric rail 20, so the width in the y direction of the area where the average luminance Is is reduced due to the connector 17 is larger than that of other accessories.

[0037] Of the accessories, the only accessory whose presence increases the average luminance Is is the support bracket 16. The support bracket 16 has an insulator that extends downward in a circular shape, which increases the average luminance Is due to the wide area in which bright lines are formed and the high light reflectivity of the insulator surface. Therefore, it can be determined that the support bracket 16 is present in the area where Is - f1 > 0 (see Figure 1(c)).

[0038] On the other hand, in areas where bolts 15 or connectors 17 are present, the average brightness Is is lower than in areas where there are no accessories, so Is - f1 < 0. The width W1 used for moving average filter f1 is set to a sufficiently wide width so that f1 is always approximately equal to the Is value in areas where there are no accessories. The width W2 used for moving average filter f2 is set relatively small so that f2 is small in areas where connectors 17 are present and so that the influence of the width of connectors 17 is fully reflected. In other words, at least W1 > W2.

[0039] Therefore, in areas where there are connector fittings 17, f2 is smaller than f1, making it possible to determine the presence of connector fittings 17 (see Figure 1(d)). Furthermore, in areas where there are no connector fittings, moving average filter f1 is likely to be affected multiple times by bolts 15, which appear at short intervals corresponding to width W1, whereas moving average filter f2 is likely to be affected by bolts 15 less frequently corresponding to width W2. Furthermore, the moving average filter f1 with a wider width W1 is more likely to be affected by support fittings 16 with a high average brightness Is within the range of width W1 or W2. In other words, in areas where there are no connector fittings, f2 is equal to or greater than f1, i.e., f2-f1≧0. Furthermore, by also considering the above-mentioned condition for Is-f1<0 to hold, the presence of bolts 15 can be determined (see Figure 1(b)).

[0040] Once the longitudinal position and longitudinal width of the accessory are detected in this manner, it is determined that the reference surface 21a is in the shadow of the laser beam L at that position, and therefore a sufficient bright line cannot be obtained from the reference surface 21a. Then, at such a position, the frame image 20a can be corrected to determine the position of the bright lines B2 and / or B3 corresponding to the reference line 21a, and the position at which the template 20b is to be superimposed. One possible correction method is, for example, correction by interpolation.

[0041] As shown in Figure 7, for each accessory frame F0 corresponding to the detected longitudinal position and longitudinal width of the accessory, there are two frames, immediately before and after F1 and F2, corresponding to the undetected longitudinal positions and longitudinal widths of the accessory parts before and after it.

[0042] At this time, as shown in FIG. 8, bright lines B2 and B3 corresponding to the reference plane 21a are identified in a pair of images consisting of frame images 20a obtained in the immediately preceding frame F1 and the immediately succeeding frame F2. Then, based on the identified bright lines B2 and B3, bright lines B2 and / or B3 are interpolated into the frame image 20a of the accessory frame F0. For example, the correction point P(x, y, z) is determined as the internal division point of point P(x, y, z) forming bright line B3 in the frame image 20a of the immediately preceding frame F1 and point P(x, y, z) forming bright line B3 in the frame image 20a of the immediately succeeding frame F2, thereby reproducing bright line B3 in the frame image 20a of the accessory frame F0. In other words, a correction is performed by interpolating the bright lines.

[0043] This allows the template 20b to be correctly superimposed on the frame image 20a in the accessory frame F0 as well, enabling the amount of wear to be measured. In other words, by including a correction step for correcting the frame image 20a, the reference surface 21a can be identified even when it is not possible to directly detect it, and various information necessary for the maintenance and management of the electric rail 20, such as the amount of wear, can be stably obtained. Note that the accessory frame F0 may include multiple consecutive frame images 20a, and similar correction can be performed on each frame image 20a, that is, for each frame of the imaging data.

[0044] In addition, the correction may involve not only the interpolation described above but also extrapolation. That is, two frames are determined on one side of the accessory frame F0, temporally adjacent to the accessory frame F0, and the two corresponding frame images 20a are set as a pair of images. Then, an external division point corresponding to the frame image 20a of the accessory frame F0 is determined from the bright line on the pair of images, and a bright line is created. Such interpolation and extrapolation can be used depending on the longitudinal width of the accessory frames F0, which are arranged at a predetermined interval. For example, a threshold value for the longitudinal width may be set in advance, and when the longitudinal width of the accessory frame F0 is larger than this threshold, the external division point of the pair of images may be used; when it is smaller, the internal division point of the pair of images may be used. This allows for relatively accurate correction.

[0045] The above describes an example of a method for obtaining the amount of wear on the head 23 of the contact wire 20, as one piece of information necessary for the maintenance and management of the contact wire 20. However, the above method also allows for the acquisition of information on at least the type of accessory, its longitudinal position, and its longitudinal width. This information is also one piece of information necessary for the maintenance and management of the contact wire 20. For example, by comparing this information with the periodicity of the fixed attachment positions and the shape (lengthwise size) of the accessory, it is possible to detect abnormalities such as deformation, detachment, and misalignment of the accessory, as well as the attachment of objects other than the accessory.

[0046] While the exemplary embodiments of the present invention and the accompanying modifications have been described above, the present invention is not necessarily limited thereto and can be modified as appropriate by those skilled in the art. In other words, those skilled in the art will be able to find various alternative embodiments and modifications without departing from the scope of the appended claims. [Explanation of symbols]

[0047] 1. Inspection equipment 2 Light irradiation unit 3. Imaging unit 20 Train Lines F0 Accessory frame F1 Last Frame Frame immediately after F2 B1~B3 bright line

Claims

1. A train track inspection method in which a strip-shaped light beam is irradiated onto the train track perpendicular to the longitudinal direction from above a vehicle running on the track, and an optical image of the illuminated area is captured, The overhead contact line is an overhead rigid contact line made of conductive steel rails with a dumbbell-shaped cross section, with a foot section and a head section connected at a central constricted section, the upper surface of the foot section being fixed and the lower surface of the head section being the sliding surface, a step of irradiating the light beam onto the sliding surface and a reference surface extending from the central constricted portion toward the outer tip of the foot portion, optically photographing the sliding surface and the reference surface irradiated with the light beam at regular intervals, and analyzing image data consisting of a plurality of frame images obtained along the direction in which the track extends; an extraction step of extracting an image corresponding to the electric train line from each of the frame images; a correction step of correcting each of the frame images from a series of brightness data of the frame images.

2. 2. The overhead rigid contact line inspection method according to claim 1, wherein the correction step acquires the longitudinal positions and longitudinal widths of the contact line accessories from the changes in the series of brightness data.

3. 3. The overhead rigid train line inspection method according to claim 2, wherein the correction step performs image correction using a pair of images made up of the frame images corresponding to both sides of the longitudinal position and the longitudinal width, for each frame of the imaging data, so that a second straight bright line corresponding to the reference surface is formed on both sides of a first straight bright line corresponding to the sliding surface.

4. 4. The overhead rigid train line inspection method according to claim 3, wherein a threshold value is determined in advance for the longitudinal width, and when the longitudinal width is larger than the threshold value, an external dividing point of the pair of images is used to correct the second straight bright line, and when the longitudinal width is smaller than the threshold value, an internal dividing point of the pair of images is used to correct the second straight bright line.

5. 5. An inspection method for an overhead rigid contact line according to claim 1, wherein each of the frame images is compared with a known cross-sectional shape of the contact line to measure the amount of wear on the sliding surface.

Images