Track gauge measurement device, and track gauge measurement method

Abstract

To provide technology that can highly accurately measure a track gauge from point group data representing a rail shape.SOLUTION: A track gauge measurement device, which measures a track gauge serving as a distance between right and left rails on the basis of point group data indicative of a position of a reflection point gained by receiving reflection light to irradiation light with which a pair of right and left rails is irradiated, is configured to: extract partial point group data corresponding to around a rail head of the point group data for each of the left and right rails; calculate, regarding the right and left rails, a representative position based on a position the partial point group data corresponding to the rail indicates; calculate the intermediate position of the representative position of the right and left rails; determine a head-part candidate position on the basis of the position relationship between the corresponding partial point group data and the intermediate position regarding the right and left rails; and decide the distance between the head candidate positions of the right and left rails as a track gauge.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an inter-rail measurement device and the like.

Background Art

[0002] As one of the maintenance inspections in railways, there is measurement of the gauge, which is the distance between rails. For gauge measurement, it has been common to use a gauge or a track inspection vehicle. Since the measurement by a gauge is performed manually, it takes a very long time for the inspection of the entire line, and it is a static measurement in which no vehicle load is applied to the rails. As gauge measurement, it is desirable to perform dynamic measurement in which a vehicle load is applied to the rails, but having a dedicated track inspection vehicle for performing such measurement can be a significant burden in terms of cost. By the way, a method of detecting the shape of a rail by applying a technique for detecting the shape of an object based on reflected light received after irradiating laser light to rail inspection has been proposed (see, for example, Patent Document 1). If the rail shape can be detected, it is considered possible to calculate the gauge from the rail shape.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, as a new object shape detection technology, a technology that represents an object shape as point cloud data by three-dimensional surveying typified by LiDAR (Light Detection And Ranging) has become widely known. Applying this technology to track measurement, it is conceivable to obtain the rail shape as point cloud data and calculate the track. Since point cloud data is a set of three-dimensional positions indicating each point on the object surface, it has the advantage of easy arithmetic processing. On the other hand, since the object shape is discretely represented by a set of "points" rather than "surfaces", the track is estimated and calculated, and its accuracy may become a problem. For this reason, a specific method for measuring the track from the point cloud data representing the rail shape has not yet been established.

[0005] The problem to be solved by the present invention is to provide a technology capable of accurately measuring the track from point cloud data representing the rail shape.

Means for Solving the Problem

[0006] The first invention for solving the above problems is An inter-track measurement device that measures the track, which is the distance between the left and right rails, based on point cloud data indicating the positions of reflection points obtained by receiving the reflected light with respect to the irradiation light irradiated toward a pair of left and right rails, Extraction means (for example, extraction unit 202 in FIG. 7) for extracting partial point cloud data corresponding to the vicinity of the rail head from the point cloud data for each of the left and right rails, For the left and right rails, representative position calculation means (for example, centroid position calculation unit 204 in FIG. 7) for calculating a representative position based on the positions indicated by the partial point cloud data corresponding to the rail, Intermediate position calculation means (for example, intermediate position calculation unit 206 in FIG. 7) for calculating the intermediate position of the representative positions of the left and right rails, For the left and right rails, determination means (for example, determination unit 208 in FIG. 7) for determining a head candidate position based on the positional relationship between the corresponding partial point cloud data and the intermediate position, An inter-track measurement device comprising the above, and the distance between the head candidate positions of the left and right rails is taken as the track.

[0007] As another invention, A gauge measurement method for measuring the gauge, which is the distance between the left and right rails, based on point cloud data indicating the positions of reflection points obtained by receiving reflected light with respect to irradiation light irradiated toward a pair of left and right rails, comprising: Extracting partial point cloud data corresponding to the vicinity of the rail head from the point cloud data for each of the left and right rails (for example, step S1 in FIG. 2); Calculating representative positions for the left and right rails based on the positions indicated by the partial point cloud data corresponding to the respective rails (for example, step S3 in FIG. 2); Calculating an intermediate position between the representative positions of the left and right rails (for example, step S5 in FIG. 2); Determining head candidate positions for the left and right rails based on the positional relationship between the corresponding partial point cloud data and the intermediate position (for example, step S7 in FIG. 2); Taking the distance between the head candidate positions of the left and right rails as the gauge (for example, step S9 in FIG. 2); A gauge measurement method including the above may be configured.

[0008] According to the first invention and the like, a technique capable of accurately measuring the gauge from point cloud data representing the rail shape can be realized. That is, a representative position is calculated based on partial point cloud data corresponding to the vicinity of the rail head extracted separately for the left and right rails from the point cloud data obtained by measuring the rails, and the distance between the head candidate positions of the left and right rails determined based on the positional relationship between the intermediate position of the representative positions and the partial point cloud data is taken as the gauge. Since the left and right rail shapes are substantially line-symmetric in the track cross-section, the logic of calculating the intermediate position between the left and right rails and determining the head candidate positions of the left and right rails based on the intermediate position is realized. Therefore, it is possible to accurately calculate the gauge.

[0009] A second invention is the above-described invention, wherein The representative position calculating means calculates the center of gravity position of the positions of the respective reflection points constituting the partial point cloud data as the representative position. A gauge measurement device.

[0010] According to the second invention, since the left and right rail shapes in the track cross-section are substantially line-symmetrical, the distribution of the reflection points constituting the partial point group data is also substantially line-symmetrical, and the center-of-gravity position can also be in a substantially line-symmetrical position. As a result, the intermediate position between the center-of-gravity positions of the left and right rails can be regarded as a substantially intermediate position between the left and right rails, contributing to an improvement in the calculation accuracy of the rail gauge.

[0011] The third invention is the above-described invention, wherein the determination means determines, as the head candidate position, the position closest to the intermediate position among the positions of the reflection points constituting the partial point group data. It is a rail gauge measuring device.

[0012] Since the rail gauge is the shortest distance between the inner sides of the left and right rail heads, according to the third invention, by setting the position closest to the intermediate position as the head candidate position, the calculation accuracy of the rail gauge can be improved.

[0013] The fourth invention is the above-described invention, wherein the point group data further includes data indicating the luminance of the reflection points, and the extraction means further extracts the partial point group data based on the luminance of each of the reflection points constituting the point group data. It is a rail gauge measuring device.

[0014] According to the fourth invention, since generally the rail is made of steel and is easy to reflect light, by basing on the luminance of the reflection points, the reflection points corresponding to the rail heads can be accurately extracted as partial point group data from the point group data. As a result, it becomes possible to improve the calculation accuracy of the rail gauge.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

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Figure 7

Embodiments for Carrying Out the Invention

[0016] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Note that the applicable forms of the present invention are not limited to the following embodiments. Also, in the description of the drawings, the same reference numerals are assigned to the same elements.

[0017] The track gauge measuring device 1 of the present embodiment is a device that calculates the track gauge, which is the interval between the rails, from the point cloud data obtained by receiving the reflected light with respect to the irradiation light irradiated toward a pair of left and right rails.

[0018] The point cloud data is, for example, data measured by a LiDAR sensor attached under the floor of a railway vehicle running on a track. The LiDAR sensor is a sensor that irradiates pulsed laser light such as near-infrared light as the irradiation light and generates point cloud data indicating the three-dimensional position and luminance of each reflection point as measurement data. Note that the point cloud data is not limited to the measurement data by the LiDAR sensor, and may be, for example, measurement data by other sensors using light wave ranging such as a three-dimensional laser scanner, or data generated using photogrammetry.

[0019] The LiDAR sensor is mounted at a substantially central position in the left-right direction (vehicle width direction) under the floor of the railway vehicle. Then, pulsed laser light is irradiated so as to scan along the left-right direction (gauge direction) toward the lower rail, and based on the received reflected light, point cloud data indicating the three-dimensional position and luminance of each reflection point is generated. Accordingly, point cloud data measuring the cross-sectional shape of the track including the rail is generated. Further, the LiDAR sensor repeatedly performs this measurement of the rail (generation of point cloud data) while the railway vehicle is running. Thereby, point cloud data corresponding to each running position (kilometer level) of the railway vehicle is generated.

[0020] FIG. 1 shows an example of point cloud data measured and generated by the LiDAR sensor. In FIG. 1, with the horizontal axis (X-axis) being the gauge direction and the vertical axis (Y-axis) being the height direction, the positions of each reflection point constituting the point cloud data are plotted. Since the positions of each reflection point constituting the point cloud data are expressed in three-dimensional coordinates with the position of the LiDAR sensor as the reference (origin O), each reflection point has an X value (gauge direction) in the range from a negative value to a positive value around “0 (zero)” corresponding to a substantially central position between the rails, and a Y value (height direction) is plotted in the range of negative values that is downward as seen from the LiDAR sensor. Since the LiDAR sensor irradiates pulsed laser light from above the rail at a substantially central position between the left and right rails, the obtained point cloud data is data of the cross-sectional shape of the track orthogonal to the running direction including the inside of the rail head.

[0021] Note that the position of each reflection point is regarded as a two-dimensional position on the X-axis in the gauge direction (width direction) and the Y-axis in the height direction because the gauge is the shortest distance inside the left and right rail heads, and for calculating this gauge, the two-dimensional positions in the gauge direction (X-axis) and the height direction (Y-axis) corresponding to the track cross-section are sufficient.

[0022] FIG. 2 is a flowchart for explaining the gauge measurement process of calculating the gauge of a rail from the point cloud data obtained by measuring the rail, which is performed by the gauge measurement device 1. As described above, the point cloud data obtained by measuring the rail is generated corresponding to each running position (kilometer level) of the railway vehicle. FIG. 2 shows the process for one running position, but it is also possible to calculate the gauge of the entire arbitrary section by repeating the same process for each running position.

[0023] In the gauge measurement process, first, partial point cloud data corresponding to the vicinity of the rail head is extracted separately for the left and right rails from the point cloud data corresponding to the target running position (step S1). As shown in FIG. 1, the point cloud data is data on the cross-sectional shape of the track, and includes, in addition to the rail, reflection points from the sleeper under the rail and the vehicle frame above the rail. Therefore, reflection points corresponding to the rail head are extracted as partial point cloud data separately for the left and right rails.

[0024] Specifically, since the LiDAR sensor is fixed under the vehicle floor and the relative positional relationship between the LiDAR sensor and the rail head is known, first, focusing on the position in the height direction (Y value), reflection points whose Y value is within a predetermined range (Y value in FIG. 1 is y1 ≦ Y ≦ y2) determined in advance as the range near the rail head including the rail head are extracted. In addition to the Y value, focusing on the position in the gauge direction (X value), reflection points whose X value is within a predetermined range (X value in FIG. 1 is X < -x1 or x2 < X) determined in advance as the range near the rail head including the rail head may be extracted. This is to exclude reflection points of objects other than the rail head of the measurement target, such as ground units and turnout rails installed on the track.

[0025] Furthermore, since rails are generally made of steel and are more likely to reflect light than their surroundings, the brightness of the reflection points on the rail surface is considered to be higher than that of other reflection points. Therefore, among the reflection points within a predetermined range, reflection points with a brightness equal to or higher than a predetermined brightness may be extracted as partial point group data. Next, focusing on the position (X value) in the gauge direction (left - right direction), the extracted reflection points are separated into the left and right rails according to the positive or negative value of the X value. For example, reflection points with a positive X value are regarded as the right rail, and reflection points with a negative X value are regarded as the left rail. In FIG. 1, partial point group data 312a corresponding to the vicinity of the head of the right rail and partial point group data 312b corresponding to the vicinity of the head of the left rail are extracted.

[0026] Subsequently, for the left and right rails, the center - of - gravity position of the positions of the respective reflection points constituting the partial point group data corresponding to the rail is calculated as a representative position based on the positions indicated by the partial point group data (step S3). FIG. 3 shows an example of the center - of - gravity positions calculated for the partial point group data for each of the left and right rails shown in FIG. 1. In FIG. 3, for ease of understanding, the center - of - gravity position is indicated by a large "square" mark.

[0027] Next, the intermediate position of the representative positions of the left and right rails is calculated (step S5). FIG. 4 shows an example of the intermediate position calculated for the center - of - gravity positions for each of the left and right rails shown in FIG. 3. In FIG. 4, for ease of understanding, the intermediate position is indicated by a large "equilateral triangle" mark.

[0028] Since the rail shape in the track cross - section is substantially line - symmetric with the vertical line passing through the central position between the rails as the axis of symmetry, the distribution of each reflection point of the partial point group data for each of the left and right rails and its center - of - gravity position are also substantially line - symmetric. Therefore, the intermediate position of the center - of - gravity positions can be regarded as the substantially central position between the left and right rails. Also in the example of FIG. 5, the intermediate position has an X value of "about 0 (zero)", and it can be said that it is the substantially central position between the left and right rails.

[0029] Subsequently, for the left and right rails, the candidate head positions of the rails are determined based on the positional relationship between the corresponding partial point group data and the intermediate position. Specifically, among the positions of the reflection points constituting the partial point group data, the position closest to the intermediate position is determined as the candidate head position (step S7). Here, the reason for setting the candidate head position as the position closest to the intermediate position is that the gauge is the shortest distance inside the rail head. Fig. 5 shows an example of the candidate head positions determined for the left and right rails shown in Fig. 4. In Fig. 5, for ease of understanding, the candidate head positions are indicated by large "diamond-shaped" marks.

[0030] Then, the distance between the candidate head positions of the left and right rails is taken as the gauge (step S9). In Fig. 5, the candidate head position corresponding to the right rail is around (X = 530, Y = -1020), and the candidate head position corresponding to the left rail is around (X = -530, Y = -1020). Therefore, the gauge is "about 1060".

[0031] Fig. 6 is a diagram showing the measurement result of the gauge by the gauge measurement device 1 of the present embodiment. The measurement was performed by running a railway vehicle with a LiDAR sensor attached under the floor and acquiring the point group data corresponding to each of a plurality of running positions during the running, and based on the acquired point group data. That is, for each of the plurality of running positions where the point group data was generated, the gauge was calculated based on the point group data corresponding to the running position.

[0032] In Fig. 6, for each of the plurality of running positions, the gauge calculated by the gauge measurement device 1 of the present embodiment is shown as "gauge (embodiment)", and for comparison, the gauge actually measured using a gauge is also shown as "gauge (measured value)". Comparing "gauge (embodiment)" and "gauge (measured value)" for each running position, the two are almost the same, and it can be said that according to the gauge measurement device 1 of the present embodiment, the gauge can be calculated with high accuracy.

[0033] FIG. 7 is a block diagram showing an example of the functional configuration of the gauge measurement device 1. The gauge measurement device 1 may be configured integrally with a LiDAR sensor attached under the floor of a railway vehicle, but in this embodiment, it will be described as being configured separately. According to FIG. 7, the gauge measurement device 1 includes an operation unit 102, a display unit 104, a communication unit 106, a processing unit 200, and a storage unit 300, and can be configured as a kind of computer.

[0034] The operation unit 102 is realized by an input device such as a button switch, a touch panel, a keyboard, etc., and outputs an operation signal corresponding to the performed operation to the processing unit 200. The display unit 104 is realized by a display device such as an LCD (Liquid Crystal Display) or a touch panel, and performs various displays according to the display signal from the processing unit 200. The communication unit 106 is realized by a communication device such as wired or wireless, and communicates with an external device via a given communication network.

[0035] The processing unit 200 is realized by an arithmetic device such as a CPU (Central Processing Unit), etc., and based on programs, data, etc. stored in the storage unit 300, gives instructions and transfers data to each part constituting the gauge measurement device 1, and performs overall control of the gauge measurement device 1. Also, the processing unit 200 functions as each functional block of an extraction unit 202, a center-of-gravity position calculation unit 204, an intermediate position calculation unit 206, a determination unit 208, and a gauge calculation unit 210 by executing the gauge measurement program 302 stored in the storage unit 300. However, these functional blocks can also be configured as independent arithmetic circuits by an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), etc.

[0036] The extraction unit 202 extracts partial point cloud data corresponding to the vicinity of the rail head from among the point cloud data indicating the positions of the reflection points obtained by receiving the reflected light with respect to the irradiation light irradiated toward the pair of left and right rails, separately for the left and right rails. Further, if the point cloud data further includes data indicating the luminance of the reflection points, the extraction unit 202 may further extract the partial point cloud data based on the luminance of each reflection point constituting the point cloud data.

[0037] Specifically, for example, the gauge measurement device 1 acquires the point cloud data 310 for each running position measured and generated by a LiDAR sensor attached under the floor of a railway vehicle, and stores it in the storage unit 300. Any method can be adopted as the method for acquiring the point cloud data 310. For example, it may be stored cumulatively in a memory provided in the LiDAR sensor during measurement by the LiDAR sensor, and read from the memory after measurement for acquisition, or the measurement data output from the LiDAR sensor may be acquired at any time and stored as the point cloud data 310 for each running position. In any case, the gauge measurement device 1 acquires the point cloud data 310 for each running position and stores it in the storage unit 300. Thereafter, the extraction unit 202 extracts, from among the point cloud data 310 corresponding to the running position to be measured for the gauge, the reflection points whose Y value is within a predetermined range defined in advance as the range in the vicinity of the rail head including the rail head. Further, reflection points whose Y value is within the predetermined range and whose luminance is equal to or higher than a predetermined luminance may be extracted. Next, the extracted reflection points are separated into partial point cloud data 312 corresponding to the rail head for the left and right rails according to the Y value, for example, the reflection points with a positive X value are regarded as the right rail, and the reflection points with a negative X value are regarded as the left rail (see FIG. 1).

[0038] The centroid position calculation unit 204 calculates a representative position based on the positions indicated by the partial point cloud data corresponding to each of the left and right rails. For example, the centroid position of the positions of the respective reflection points constituting the partial point cloud data is calculated as the representative position (see FIG. 3).

[0039] The intermediate position calculation unit 206 calculates the intermediate position of the representative positions of the left and right rails (see FIG. 4).

[0040] Based on the positional relationship between the corresponding partial point group data and the intermediate position for the left and right rails, the determination unit 208 determines the head candidate positions. For example, among the positions of the reflection points constituting the partial point group data, the position closest to the intermediate position is determined as the head candidate position (see FIG. 5).

[0041] The gauge calculation unit 210 calculates the distance between the head candidate positions of the left and right rails as the gauge (see FIG. 5). The calculated gauge is stored as gauge data 320 in association with the traveling position to be measured.

[0042] Returning to FIG. 7, the storage unit 300 is realized by a storage device such as a hard disk, ROM (Read Only Memory), or RAM (Random Access Memory), stores programs, data, etc. for the processing unit 200 to integrally control the gauge measurement device 1, and is used as a working area for the processing unit 200. The calculation results obtained by the processing unit 200 executing according to various programs, input data via the operation unit 102 and the communication unit 106, etc. are temporarily stored. In the present embodiment, the storage unit 300 stores a gauge measurement program 302, point group data 310, and gauge data 320.

[0043] [Advantages and Effects] According to the present embodiment, it is possible to realize a technique for accurately measuring the gauge from the point group data representing the rail shape. That is, the gauge measurement device 1 calculates the center of gravity position of the reflection points of the partial point group data corresponding to the vicinity of the rail head extracted separately for the left and right rails from the point group data 310 obtained by measuring the rails as the representative position based on the partial point group data, and the distance between the head candidate positions of the left and right rails determined based on the positional relationship between the intermediate position of the center of gravity position and the partial point group data is taken as the gauge. Since the left and right rail shapes are substantially line-symmetric in the cross-section of the track, the logic of calculating the intermediate position of the left and right rails and determining the head candidate positions of the left and right rails based on the intermediate position is realized. Therefore, it is possible to accurately calculate the gauge.

[0044] [Modification Example] Note that the applicable embodiments of the present invention are not limited to the above-described embodiments, and it goes without saying that they can be appropriately changed without departing from the spirit of the present invention.

[0045] (A) Center of gravity position as the representative position For example, when acquiring point cloud data for each of a plurality of traveling positions, when calculating the center of gravity position corresponding to a certain traveling position, the difference (deviation) from the center of gravity positions corresponding to one or a plurality of traveling positions before and after that may be considered. For example, when the difference in the center of gravity positions corresponding to the preceding and succeeding traveling positions is large, since the point cloud data, which is the measurement data, is inaccurate, the gauge width of the traveling position may not be calculated, or it can be corrected based on the center of gravity positions of the preceding and succeeding traveling positions.

[0046] (B) Head candidate position Reflected points that are higher than the height (Y value) of the lower of the representative positions (center of gravity positions in the above embodiment) of the left and right rails may be extracted from the partial point cloud data of the left and right rails, and the head candidate position may be determined from among the extracted reflected points. That is, the head candidate position is determined from the partial point cloud data excluding the reflected points whose position in the height direction (Y value) is lower than the lower of the representative positions of the left and right rails.

[0047] This is to exclude the influence of reflected points of rail joint plates or the like that are inside the rail head. That is, at the location where the rail joint plate exists on the rail web, the reflected points of the rail joint may be included in the partial point cloud data, but since the rail joint plate is at a position lower than the rail head, for example, the reflected points at positions lower than that are excluded from the partial point cloud data based on the representative position to determine the rail head position. Note that since the representative position of the partial point cloud data at the location where the rail joint plate exists may be at a lower position compared to the location where it does not exist, it is possible to exclude the reflected points of the rail joint plate at positions lower than that from the partial point cloud data while leaving the reflected points of the rail head.

[0048] (C) Mounting location of the LiDAR sensor The mounting location of the LiDAR sensor is not limited to under the floor of the railway vehicle. For example, any location where the track can be measured from a position approximately in the center in the left-right direction (vehicle width direction) of the railway vehicle, such as the through door section of the leading vehicle, is acceptable. Also, not limited to railway vehicles, for example, a LiDAR sensor may be similarly mounted on a track cart to measure the rail.

Explanation of Signs

[0049] 1…Gauge measurement device 200…Processing unit 202…Extraction unit 204…Center of gravity position calculation unit 206…Intermediate position calculation unit 208…Determination unit 210…Gauge calculation unit 300…Storage unit 302…Gauge measurement program 310…Point cloud data 320…Gauge data

Claims

1. An gauge measurement device for measuring the gauge, which is the distance between the left and right rails, based on point cloud data indicating the positions of reflection points obtained by receiving the reflected light with respect to the irradiation light irradiated toward the pair of left and right rails, an extraction means for extracting partial point cloud data corresponding to the vicinity of the rail head from among the point cloud data for each of the left and right rails; a representative position calculation means for calculating a representative position based on the positions indicated by the partial point cloud data corresponding to the respective left and right rails; an intermediate position calculation means for calculating an intermediate position of the representative positions of the left and right rails; a determination means for determining a head candidate position based on the positional relationship between the corresponding partial point cloud data and the intermediate position for the left and right rails; The gauge measurement device comprising the above, and using the distance between the head candidate positions of the left and right rails as the gauge.

2. The representative position calculation means calculates the center of gravity position of the positions of the respective reflection points constituting the partial point cloud data as the representative position. The gauge measurement device according to Claim 1.

3. The determination means determines, as the head candidate position, the position closest to the intermediate position among the positions of the reflection points constituting the partial point cloud data. The gauge measurement device according to Claim 1 or 2.

4. The point cloud data further includes data indicating the luminance of the reflection points, and the extraction means further extracts the partial point cloud data based on the luminance of each of the reflection points constituting the point cloud data. The gauge measurement device according to Claim 1 or 2.

5. A gauge measurement method for measuring the gauge, which is the distance between the left and right rails, based on point cloud data indicating the positions of reflection points obtained by receiving the reflected light with respect to the irradiation light irradiated toward the pair of left and right rails, extracting partial point cloud data corresponding to the vicinity of the rail head from among the point cloud data for each of the left and right rails; calculating a representative position based on the positions indicated by the partial point cloud data corresponding to the respective left and right rails; calculating an intermediate position of the representative positions of the left and right rails; determining a head candidate position based on the positional relationship between the corresponding partial point cloud data and the intermediate position for the left and right rails; using the distance between the head candidate positions of the left and right rails as the gauge; The gauge measurement method including the above.

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