Travel path estimation method and travel path estimation device

Abstract

To estimate a geometry of a running path at an intersection even in a region where a traveling track has not been acquired.SOLUTION: A running path estimation method includes: acquiring data indicating positions and directions of a plurality of road surface arrow signs before an intersection; acquiring data indicating a traveling track of a vehicle traveling in the intersection; calculating a distance in a vehicle lane width direction from the traveling track to each of the plurality of road surface arrow signs; determining a destination of the traveling track on the basis of a direction of a reference road surface arrow sign, which is a road surface arrow sign with a distance of less than a first threshold value; generating data indicating a duplicated traveling track by duplicating the traveling track by translating it to a position of a road surface arrow sign indicative of the same direction as the destination of the traveling track and being different from the reference road surface arrow sign; and estimating a geometry of a running path in the intersection on the basis of the data indicating the duplicated traveling track.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a roadway estimation method and a roadway estimation device. [Background technology]

[0002] Patent Document 1 discloses a lane map generating device that generates a highly accurate lane-level map by detecting a group of center points of each driving lane from an image captured by a camera mounted on a vehicle, storing the detected group of center points in association with each link on a road network, and generating center lines for each driving lane corresponding to each link.At intersections, this lane map generating device associates entrance points to the intersection with exit points from the intersection, and estimates the driving lanes within the intersection using spline curves connecting the entrance points, midpoints, and exit points. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-4814 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional lane map generation device described above, the direction of the entrance point is determined to establish correspondence between the entrance point and the exit point of an intersection. To determine the direction of the entrance point, a statistical analysis of the driving trajectory that passes through both the entrance point and the exit point may be performed. In this case, in order to estimate the driving lane within the intersection, it is necessary to acquire multiple driving trajectories that actually pass through both the entrance point and the exit point of the driving lane.

[0005] The present invention has been made in consideration of the above problems, and aims to provide a roadway estimation method and roadway estimation device that can estimate the shape of a road even in areas at intersections where no driving trajectory has been acquired. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, a lane estimation method and device according to one embodiment of the present invention acquires data indicating the positions and directions of multiple road arrow markings just before an intersection, acquires data indicating the driving trajectory of a vehicle traveling through the intersection, calculates the distance in the lane width direction from the driving trajectory to each of the multiple road arrow markings, determines the destination of the driving trajectory based on the direction of a reference road arrow marking, which is a road arrow marking whose distance is less than a first threshold, generates data indicating a duplicate driving trajectory by translating the driving trajectory to the position of a road arrow marking that is different from the reference road arrow marking and indicates the same direction as the destination of the driving trajectory, and estimates the shape of the lane within the intersection based on the data indicating the duplicate driving trajectory. [Effects of the Invention]

[0007] According to the present invention, it is possible to estimate the shape of a road at an intersection even in an area where a travel trajectory has not been acquired. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing an example of the configuration of a roadway estimation device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram for explaining examples of road arrow markings and the positions of the road arrow markings. [Figure 3] FIG. 3 is a flowchart showing an example of the flow of operations performed by the path estimation unit of the path estimation device according to one embodiment of the present invention. [Figure 4] FIG. 4 is a flowchart showing the processing steps of a travel locus destination determination process performed by the travel path estimation unit of the travel path estimation device according to one embodiment of the present invention. [Figure 5] FIG. 5 is a diagram for explaining a method for determining the destination of a travel locus. [Figure 6] FIG. 6 is a diagram for explaining a method for determining the destination of a travel locus. [Figure 7] FIG. 7 is a flowchart showing the processing steps of the travel trajectory duplication process performed by the travel path estimation unit of the travel path estimation device according to one embodiment of the present invention. [Figure 8] FIG. 8 is a diagram for explaining a method for duplicating a travel locus. [Figure 9] FIG. 9 is a diagram for explaining a method for duplicating a travel locus. [Figure 10A] FIG. 10A is a diagram for explaining a method for adjusting the turning radius of a traveling locus. [Figure 10B] FIG. 10B is a diagram for explaining a method for adjusting the turning radius of the traveling locus. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same parts are designated by the same reference numerals and the description thereof will be omitted.

[0010] [Example of configuration of a roadway estimation device] An example of the configuration of a roadway estimation device according to this embodiment will be described with reference to Fig. 1. As shown in Fig. 1, the roadway estimation device 1 includes a recognition unit 10, a storage unit 11, a car navigation system 12, a roadway estimation unit 13, a camera 20, a LiDAR (Light Detection and Ranging) 30, and a GNSS (Global Navigation Satellite System) receiver 40, and is configured using, for example, an IC, an LSI, or the like.

[0011] The path estimation device 1 is composed of general-purpose electronic circuits including a microcomputer, a microprocessor, and a CPU (Central Processing Unit), as well as peripheral devices such as memory. Each function of the path estimation device 1 can be implemented by one or more processing circuits. The processing circuit includes a programmed processing device, such as a processing device including an electrical circuit, and also includes devices such as an application specific integrated circuit (ASIC) or conventional circuit components arranged to perform the functions described in the embodiments. The path estimation device 1 according to this embodiment is mounted on a vehicle.

[0012] The camera 20 has an imaging element such as a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). The camera 20 is mounted on the host vehicle and captures images of the area ahead of the host vehicle at predetermined time intervals. The camera 20 outputs the captured images of the area ahead of the host vehicle to the recognition unit 10.

[0013] The LiDAR 30 is a sensor that detects environmental information around the vehicle using LiDAR, an optical sensor technology. Specifically, the LiDAR 30 scans a laser beam within a certain angle range, receives the reflected light, and measures the time difference between the time the laser is emitted and the time the reflected light is received to detect the relative distance and direction of other vehicles with respect to the host vehicle (i.e., their relative positions with respect to the host vehicle). The LiDAR 30 outputs the detected data to the recognition unit 10. Note that the LiDAR 30 may be any sensor that detects the relative positions of other vehicles present around the host vehicle with respect to the host vehicle, and may use sensors other than LiDAR, such as laser radar or sonic radar. Furthermore, a LiDAR and a plurality of different types of sensors other than LiDAR may be used.

[0014] The GNSS receiver 40 calculates position information indicating the latitude, longitude, and altitude of the vehicle based on signals received from multiple navigation satellites, and detects the position of the vehicle on the ground. The GNSS is, for example, a GPS receiver in a Global Positioning System (GPS). The GNSS receiver 40 outputs the position information of the vehicle to the recognition unit 10 and the car navigation system 12.

[0015] The recognition unit 10 is connected to the camera 20, the LiDAR 30, and the GNSS receiver 40, and includes an arrow mark detection unit 101 and a traveling trajectory detection unit 102.

[0016] The arrow marking detection unit 101 detects road arrow markings (hereinafter simply referred to as arrow markings) that indicate the destination of a lane from an image captured by the camera 20. The arrow marking detection unit 101 generates a projection image by projecting the acquired forward image onto a plane (road surface). The arrow marking detection unit 101 generates the projection image and identifies the positions and directions of multiple arrow markings in front of an intersection, for example, as shown in FIG. 2. The identification of the positions and directions of the arrow markings is performed by image processing such as template matching. The method of identifying the positions and directions of arrow markings by image processing is a known technique, so a detailed description will be omitted. The arrow marking detection unit 101 sets a reference line segment that passes through the center position in the lane width direction for each of the multiple arrow markings. For example, the arrow marking detection unit 101 identifies the area of ​​the arrow marking Y from the size of a template T of the arrow marking Y on the projection image, and sets a reference line segment BL as the position of the arrow marking Y. The length of the reference line segment BL is set according to the length of the template T in the lane direction, and matches the length of the arrow marking Y. Furthermore, the "direction of the arrow marking" here refers to the destination of the lane on which the arrow marking is located, such as "go straight," "turn right," or "turn left." Note that the types of arrow markings are not limited to those shown in FIG. 2, but since the types of arrow markings Y are finite, it is possible to detect the positions and directions of all types of arrow markings.

[0017] The arrow sign detection unit 101 outputs to the storage unit 11 data indicating the positions and directions of the detected arrow signs in front of the intersection.

[0018] The traveling trajectory detection unit 102 detects the traveling trajectory of the other vehicle using the time-varying change in the position of the other vehicle around the host vehicle detected by the LiDAR 30 and the position information of the host vehicle detected by the GNSS receiver 40. For example, the traveling trajectory detection unit 102 verifies (associates) the identity of the other vehicle at different times based on the detection results of the other vehicle around the host vehicle detected by the LiDAR 30, and detects the time-varying change in the position of the other vehicle based on the association. The method of detecting the traveling trajectory of the other vehicle is a known technique, and therefore a detailed description thereof will be omitted.

[0019] The travel path detection unit 102 outputs data indicating the detected travel path of the other vehicle to the storage unit 11.

[0020] The memory unit 11 stores data indicating the positions and directions of multiple arrow signs just before an intersection detected by the arrow sign detection unit 101, and data indicating the driving trajectories of other vehicles detected by the driving trajectory detection unit 102.

[0021] The car navigation system 12 is a device that provides guidance on the route that the vehicle should take to reach the destination. The car navigation system 12 is connected to the GNSS receiver 40, and when the destination is input, it generates a guidance route from the current location of the vehicle (or an arbitrarily set starting point) to the destination. Information on the generated guidance route is displayed on a display (not shown).

[0022] The car navigation system 12 includes a locator 121 and map information 122. The locator 121 acquires latitude and longitude information of the vehicle's location from the GNSS receiver 40 and identifies the current location of the vehicle on the map in the map information 122. The car navigation system 12 identifies the road on which the vehicle is traveling from among the roads on the map, and at the same time detects an intersection into which the vehicle will enter. When the car navigation system 12 detects an intersection into which the vehicle will enter, it transmits information about the intersection into which the vehicle will enter (hereinafter referred to as intersection information) to the travel path estimation unit 13. The intersection information includes, for example, location information of the intersection. The map information 122 is information stored in the car navigation system 12 and includes various data required for route guidance, such as nodes set at predetermined intervals that indicate the location of roads, links connecting the nodes, location information of intersections, sign information, traffic light information, lane information (number of lanes, dedicated right and left turn lanes), landmark information, and facility information. The map information 122 may be updated by periodically obtaining the latest map information from a server.

[0023] The path estimation unit 13 is connected to the storage unit 11 and the car navigation system 12, and when the locator 121 of the car navigation system 12 detects an intersection, it acquires data indicating the positions and directions of multiple arrow signs just before the intersection detected by the recognition unit 10 and data indicating the path of another vehicle detected by the path detection unit 102. Then, it performs a process of determining the destination of the path of the other vehicle using the data indicating the positions and directions of the arrow signs and the data indicating the path of the other vehicle (hereinafter referred to as a path destination determination process). It also performs a process of generating data indicating a duplicate path by duplicating the path at the position of the arrow sign indicating the same direction as the destination of the determined path (hereinafter referred to as a path duplication process). Then, it performs a process of estimating the shape of the path within the intersection based on the data indicating the duplicated path.

[0024] When viewed functionally, the roadway estimation unit 13 can be classified into an intersection information acquisition unit 131, an arrow sign acquisition unit 132, a travel trajectory acquisition unit 133, a destination determination unit 134, a travel trajectory duplication unit 135, and a roadway shape estimation unit 136. An overview of each function of the roadway estimation unit 13 will be explained below.

[0025] When the car navigation system 12 detects an intersection that the host vehicle is about to enter, the intersection information acquisition unit 131 acquires intersection information from the car navigation system 12. For example, the intersection information acquisition unit 131 acquires, from the car navigation system 12, position information of the intersection that the host vehicle is about to enter.

[0026] Based on the acquired intersection information, the arrow sign acquisition unit 132 acquires data indicating the position and direction of each of the multiple arrow signs just before the intersection from the storage unit 11. For example, based on the acquired intersection position information, the arrow sign acquisition unit 132 acquires data indicating the position and direction of the multiple arrow signs just before the intersection from the storage unit 11.

[0027] Based on the acquired intersection information, the traveling locus acquisition unit 133 acquires data indicating the traveling locus of another vehicle traveling through the intersection from the storage unit 11. Based on, for example, the acquired position information of the intersection, the traveling locus acquisition unit 133 acquires data indicating the traveling locus of another vehicle traveling through the intersection from the storage unit 11.

[0028] The destination determination unit 134 performs a destination determination process for the travel trajectory. The destination determination unit 134 calculates the distance in the lane width direction from the travel trajectory of the other vehicle to each of the multiple arrow markings. If it is possible to draw a perpendicular line from the travel trajectory to a reference line segment of the arrow markings, the destination determination unit 134 calculates the distance in the lane width direction between the travel trajectory and the reference line segment at which the perpendicular line is shortest as the distance in the lane width direction from the travel trajectory to the arrow markings.

[0029] If it is not possible to draw a perpendicular line from the travel trajectory to the reference line segment of the arrow marking, the destination determination unit 134 extends the travel trajectory toward the reference line segment.The destination determination unit 134 then calculates the distance in the lane width direction between the extended travel trajectory and the reference line segment, at which the perpendicular line drawn from the extended travel trajectory to the reference line segment is the shortest, as the distance in the lane width direction from the travel trajectory to the road arrow marking.In this case, the destination determination unit 134 calculates the angle (first angle) formed between the extended travel trajectory and the reference line segment, and determines the destination of the travel trajectory if the angle is less than a second threshold value.

[0030] Furthermore, the destination determination unit 134 identifies an arrow marking in which the distance in the lane width direction from the travel trajectory of another vehicle to the arrow marking is less than a first threshold as a reference arrow marking. Of the multiple arrow markings, the destination determination unit 134 identifies a road arrow marking in which the distance in the lane width direction from the travel trajectory to the arrow marking is less than the first threshold and is the shortest. Then, the destination of the travel trajectory is determined based on the direction of the reference arrow marking. Note that, when there are multiple directions indicated by the reference arrow marking, the destination determination unit 134 calculates the curvature of the travel trajectory and determines the destination of the travel trajectory based on the curvature.

[0031] The travel trajectory duplication unit 135 identifies an arrow marking that indicates the same direction as the destination of the travel trajectory of the other vehicle and is different from the reference road arrow marking. Then, the travel trajectory of the other vehicle is translated to the position of the identified arrow marking, and data indicating a duplicated travel trajectory is generated. If it is impossible to draw a perpendicular line from the travel trajectory to the reference line segment of the arrow marking, the travel trajectory duplication unit 135 translates the travel trajectory in the lane width direction and determines whether the translated travel trajectory intersects with another travel trajectory. If the translated travel trajectory intersects with another travel trajectory, the travel trajectory duplication unit 135 calculates the angle (second angle) formed between the translated travel trajectory and the other travel trajectory, and if the angle is less than a third threshold, the travel trajectory is translated to a position where it intersects with the other travel trajectory, and data indicating a duplicated travel trajectory is generated.

[0032] The road shape estimation unit 136 estimates the shape of the road within the intersection based on data indicating the duplicated driving trajectory generated by the driving trajectory duplication unit 135. The road shape estimation unit 136 estimates the shape of the road within the intersection from a plurality of driving trajectories made up of the duplicated driving trajectories and driving trajectories within the intersection.

[0033] With the above configuration, the path estimation device 1 according to this embodiment can estimate the shape of the path within the intersection based on the travel trajectories of other vehicles acquired while traveling just before the intersection and the map information 122 of the car navigation system 12. This eliminates the need for complex processing such as searching for the exit point of the link on the road network corresponding to the entrance point of the intersection, calculating the midpoint, and calculating a spline curve connecting the entrance point, midpoint, and exit point, as in the past.

[0034] Next, the operation flow of each functional unit of the travel path estimation unit 13, the destination determination process of the travel path, and the duplication process of the travel path will be described in detail with reference to FIGS.

[0035] 3 is a flowchart showing an example of the flow of operations performed by the functional units of the road estimation unit 13. First, in step S10 of FIG.

[0036] The process proceeds to step S11, where the arrow sign acquisition unit 132 acquires, from the storage unit 11, data indicating the positions and directions of a plurality of arrow signs just before the intersection, based on the acquired intersection information.

[0037] The process proceeds to step S12, where the travel locus acquisition unit 133 acquires, from the storage unit 11, data indicating the travel locus of another vehicle traveling through the intersection, based on the acquired intersection information.

[0038] The process proceeds to step S13, where the destination determination unit 134 performs a process of determining the destination of the acquired travel locus (travel locus destination determination process). Here, a detailed method of the travel locus destination determination process will be described with reference to FIGS. 4 to 6.

[0039] [Driving trajectory destination determination process] Fig. 4 is a flowchart showing the processing procedure for determining the destination of a travel locus by the destination determination unit 134. For example, in Fig. 5, when arrows Y1 to Y3 are present before an intersection and other vehicles V1 and V2 are traveling through the intersection, the positions and directions of each of the arrows Y1 to Y3 are assumed to have been acquired. As the positions of the arrows Y1 to Y3, reference line segments BL1 to BL3 of each of the arrows Y1 to Y3 are assumed to have been acquired. Furthermore, a travel locus 501 of the other vehicle V1 and a travel locus 502 of the other vehicle V2 are assumed to have been acquired.

[0040] In step S1301 of Fig. 4, the destination determination unit 134 calculates the distance from the travel path of another vehicle to each of the multiple arrow markings just before the intersection. For example, in Fig. 5, the destination determination unit 134 draws perpendicular lines from the travel path 501 of the other vehicle V1 to each of the reference line segments BL1 to BL3 of the arrow markings Y1 to Y3, and calculates distances D1 to D3 in the lane width direction between the travel path 501 and the reference line segments BL1 to BL3 at which the perpendicular lines are shortest. On the other hand, because the travel path 502 of the other vehicle V2 is short, it is not possible to draw perpendicular lines from the travel path 502 to the reference line segments BL1 to BL3 of the arrow markings Y1 to Y3. In this case, the destination determination unit 134 does not calculate the distance from the travel path 502 to the arrow markings.

[0041] The process proceeds to step S1302, where the destination determination unit 134 performs distance determination 1. In distance determination 1, it is determined whether the distance from the travel trajectory to the arrow marking calculated in step S1301 is less than a first threshold. The first threshold may be set to a value approximately half the lane width; for example, if the lane width is 3 m, it is set to 1.5 m. In distance determination 1, if the distance from the travel trajectory to the arrow marking is less than the first threshold, the destination determination unit 134 identifies the arrow marking whose distance from the travel trajectory to the arrow marking is less than the first threshold as the reference arrow marking. The reference road arrow marking is the arrow marking whose distance from the travel trajectory to the arrow marking is less than the first threshold and is the shortest. Then, the process proceeds to step S1308.

[0042] 5, the destination determination unit 134 determines whether the distances D1 to D3 are less than a first threshold value. If the distance D1 is less than the first threshold value, the destination determination unit 134 specifies the arrow marking Y1 as the reference arrow marking.

[0043] On the other hand, in distance determination 1, if the distance from the travel path to the arrow marking is equal to or greater than the first threshold, the destination determination unit 134 ends the processing in Fig. 4, and the path estimation unit 13 ends the processing in Fig. 3. Also, in distance determination 1, if the distance from the travel path to the arrow marking is not calculated in step S1301, the destination determination unit 134 determines that distance determination is impossible, and the processing proceeds to step S1303.

[0044] In step S1303, the destination determination unit 134 extends the travel trajectory toward the reference line segment. That is, if it is impossible to draw a perpendicular line from the travel trajectory toward the reference line segment indicated by the arrow marking, the destination determination unit 134 extends the travel trajectory toward the reference line segment. Specifically, the destination determination unit 134 extends the travel trajectory toward the reference line segment by a straight line. For example, as shown in FIG. 6, the destination determination unit 134 extends the travel trajectory 502 of the other vehicle V2 in FIG. 5 toward the reference line segment BL3 by a straight line 70.

[0045] The process proceeds to step S1304, where the destination determination unit 134 calculates the distance in the lane width direction from the extended travel trajectory to each of the multiple arrow markings just before the intersection. More specifically, the destination determination unit 134 draws a perpendicular line from the straight line extending the travel trajectory to the reference line segment of the arrow marking, and calculates the distance in the lane width direction from the travel trajectory to the arrow marking as the distance in the lane width direction between the extended travel trajectory and the reference line segment where the perpendicular line is shortest. Note that if the extended travel trajectory intersects with the reference line segment, the destination determination unit 134 calculates the distance in the lane width direction from the travel trajectory to the arrow marking as 0. For example, as shown in FIG. 6 , if a straight line 70 extending the travel trajectory 502 of the other vehicle V2 intersects with the reference line segment BL3 of the arrow marking Y3, the destination determination unit 134 calculates the distance in the lane width direction from the travel trajectory 502 to the arrow marking Y3 as 0.

[0046] The process proceeds to step S1305, where the destination determination unit 134 performs distance determination 2. In distance determination 2, it is determined whether the distance from the extended travel path to the arrow marking calculated in step S1304 is less than a first threshold value. The destination determination unit 134 also identifies, as a reference arrow marking, an arrow marking whose distance from the extended travel path to the arrow marking is less than the first threshold value. The process then proceeds to step S1306.

[0047] 6, for example, in distance determination 2, the destination determination unit 134 determines that the distance from the extended travel path 502 to the arrow marking Y3 is less than the first threshold value because the distance from the extended travel path 502 to the arrow marking Y3 is 0. Furthermore, the destination determination unit 134 identifies the arrow marking Y3 as the reference arrow marking.

[0048] On the other hand, in distance determination 2, if the distance from the extended travel path to the arrow marking is equal to or greater than the first threshold, the destination determination unit 134 ends the processing of FIG. 4, and the travel path estimation unit 13 ends the processing of FIG.

[0049] In step S1306, the destination determination unit 134 calculates the angle (first angle) between the extended travel path and the reference line segment. For example, in Fig. 6, the destination determination unit 134 calculates the angle 60 between the line 70, which is an extension of the travel path 502 of the other vehicle V2, and the reference line segment BL3.

[0050] The process proceeds to step S1307, where the destination determination unit 134 performs angle determination. In the angle determination, it is determined whether the angle between the extended travel trajectory and the reference line segment calculated in step S1306 is less than a second threshold value. The second threshold value is set to, for example, an absolute value of 10 degrees. In the angle determination, if the angle between the extended travel trajectory and the reference line segment is less than the second threshold value, the process proceeds to step S1308. On the other hand, in the angle determination, if the angle between the extended travel trajectory and the reference line segment is equal to or greater than the second threshold value, the destination determination unit 134 ends the process of FIG. 4, and the path estimation unit 13 ends the process of FIG. 3.

[0051] In step S1308, the destination determination unit 134 determines whether the direction indicated by the reference arrow marking is unique. A unique direction of the reference arrow marking means that there is only one direction indicated by the reference arrow marking. Furthermore, a non-unique direction of the reference arrow marking means that there are multiple directions indicated by the reference arrow marking. If the direction indicated by the reference arrow marking is unique, the process proceeds to step S1309. On the other hand, if the direction indicated by the reference arrow marking is not unique, the process proceeds to step S1310.

[0052] In step S1309, the destination determination unit 134 determines that the destination of the travel locus is the direction of the reference arrow marking, and ends the processing in Fig. 4. For example, in Fig. 5, the destination determination unit 134 determines that the destination of the travel locus 501 is the direction of the arrow marking Y1 identified as the reference arrow marking. That is, the destination of the travel locus 501 is determined to be "right turn," and ends the processing.

[0053] In step S1310, the destination determination unit 134 calculates the curvature ρ of the travel trajectory. The process proceeds to step S1311, where the destination determination unit 134 determines whether the curvature ρ of the travel trajectory is greater than a positive threshold θ, greater than or equal to a negative threshold −θ and less than a positive threshold θ, or less than a negative threshold −θ. Here, the threshold θ is set to 1 / 100, for example. By setting the threshold θ to 1 / 100, it is possible to determine whether the travel trajectory is a right turn, a left turn, or going straight, with a turning radius of 100 m. If the curvature ρ is greater than the positive threshold θ, the process proceeds to step S1312, where the destination determination unit 134 determines that the destination of the travel trajectory is a "left turn," and the process of FIG. 4 ends. If the curvature ρ is equal to or greater than the negative threshold −θ and equal to or less than the positive threshold θ, the process proceeds to step S1313, where the destination determination unit 134 determines that the destination of the travel trajectory is “straight ahead,” and ends the process in Fig. 4. If the curvature ρ is smaller than the negative threshold −θ, the process proceeds to step S1314, where the destination determination unit 134 determines that the destination of the travel trajectory is “right turn,” and ends the process in Fig. 4.

[0054] Returning to FIG. 3, if the destination of the travel locus is determined in step S13, the process proceeds to step S14, where the travel locus duplication unit 135 performs a process of duplicating the travel locus (travel locus duplication process). The travel locus duplication unit 135 identifies an arrow marking that indicates the same direction as the destination of the travel locus of the other vehicle and that is different from the reference road arrow marking. Then, the travel locus of the other vehicle is translated to the position of the identified arrow marking to generate data indicating a duplicated travel locus. Here, the travel locus duplication process will be described in detail with reference to FIGS. 7 to 9.

[0055] [Duplication of driving trajectory] 7 is a flowchart showing the processing steps of the travel locus duplication process by the travel locus duplication unit 135. The processing in FIG. 7 is executed when the destination determination unit 134 determines the destination of the travel locus.

[0056] 7, the travel trajectory copying unit 135 determines whether or not the distance between the travel trajectory and the arrow markings can be calculated. The travel trajectory copying unit 135 acquires information from the destination determination unit 134 as to whether or not the distance between the travel trajectory of another vehicle and each of the multiple arrow markings just before the intersection has been calculated, and determines whether or not the distance between the travel trajectory and the arrow markings can be calculated. If the distance between the travel trajectory and the arrow markings can be calculated (YES in step S1401), the process proceeds to step S1402.

[0057] For example, in Fig. 8, when there are multiple arrow markings Y5 to Y7 before an intersection and another vehicle V is traveling through the intersection, arrow marking Y5 is identified as the reference arrow marking and the destination of travel trajectory 504 of the other vehicle V is determined to be "straight ahead." As shown in Fig. 8, when the length of travel trajectory 504 of the other vehicle V is sufficiently long and it is possible to draw a perpendicular line from travel trajectory 504 to a reference line segment (not shown) of arrow marking Y5, the destination determination unit 134 can calculate the distance between travel trajectory 504 and the arrow marking. Therefore, in Fig. 8, the travel trajectory duplication unit 135 determines that the distance between travel trajectory 504 and the arrow marking can be calculated.

[0058] On the other hand, if the distance between the travel locus and the arrow marking cannot be calculated (NO in step S1401), the process proceeds to step S1403. For example, in FIG. 9, when there are multiple arrow markings Y8-Y10 before an intersection and another vehicle V is traveling through the intersection, arrow marking Y8 is identified as the reference arrow marking and the destination of the travel locus 505 of the other vehicle V is determined to be "straight ahead." As shown in FIG. 9, if the length of the travel locus 505 of the other vehicle V is short and it is not possible to draw a perpendicular line from the travel locus 504 to the reference line segment (not shown) of the arrow marking Y8, the destination determination unit 134 cannot calculate the distance between the travel locus 505 and the arrow marking. Therefore, in FIG. 9, the travel locus duplication unit 135 determines that the distance between the travel locus 505 and the arrow marking cannot be calculated. 9, it is assumed that there are other vehicle travel trajectories (hereinafter referred to as other travel trajectories) 506, 607 that are different from the travel trajectory 505 of the other vehicle V. Here, it is assumed that processing is being performed on the travel trajectory 505 in FIG.

[0059] In step S1402, the travel trajectory duplicating unit 135 identifies an arrow marking that indicates the same direction as the destination of the travel trajectory and is different from the reference arrow marking. Then, the travel trajectory is translated to the position of the identified arrow marking, and the process proceeds to step S1407. For example, in FIG. 8, the travel trajectory duplicating unit 135 identifies arrow markings Y6 and Y7 that indicate the same direction as the destination "straight ahead" of the travel trajectory 504 and are different from the reference arrow marking Y5. Then, the travel trajectory 504 is translated to the positions of the identified arrow markings Y6 and Y7 in the lane width direction.

[0060] In step S1403, the traveling trajectory duplication unit 135 translates the traveling trajectory in the lane width direction. The process proceeds to step S1404, where the traveling trajectory duplication unit 135 determines whether the translated traveling trajectory intersects with another traveling trajectory. If the translated traveling trajectory intersects with another traveling trajectory (YES in step S1404), the process proceeds to step S1405. If the traveling trajectory does not intersect with another traveling trajectory (NO in step S1404), the traveling trajectory duplication unit 135 ends the process in FIG. 7, and the road estimation unit 13 ends the process in FIG. 3.

[0061] 9, for example, the traveling trajectory duplication unit 135 translates the traveling trajectory 505 in the lane width direction, and determines whether the translated traveling trajectory 505 contacts other traveling trajectories 506 and 507. In FIG. 9, the traveling trajectory duplication unit 135 determines that the translated traveling trajectory 505 contacts other traveling trajectories 506 and 507.

[0062] In step S1405, the traveling trajectory replicating unit 135 calculates the angle (second angle) formed between the translated traveling trajectory and the other traveling trajectory. The process proceeds to step S1406, where the traveling trajectory replicating unit 135 determines whether the angle formed between the translated traveling trajectory and the other traveling trajectory is less than a third threshold. The third threshold is set to an absolute value of 10 degrees, for example. If the angle formed between the translated traveling trajectory and the other traveling trajectory is less than the third threshold (YES in step S1406), the process proceeds to step S1407. On the other hand, if the angle formed between the translated traveling trajectory and the other traveling trajectory is equal to or greater than the third threshold (NO in step S1406), the traveling trajectory replicating unit 135 ends the process of FIG. 7, and the roadway estimation unit 13 ends the process of FIG. 3.

[0063] In step S1407, the traveling locus duplicating unit 135 generates a duplicated traveling locus by duplicating the traveling locus, and ends the processing in Fig. 7. Then, the traveling road shape estimating unit 136 estimates the shape of the traveling road within the intersection based on the traveling locus and the duplicated traveling locus.

[0064] 8, for example, the traveling trajectory duplication unit 135 generates duplicate traveling trajectories 701 and 702 by translating the traveling trajectory 504 to the positions of the arrow markers Y6 and Y7 and duplicating the same. Also, in FIG. 9, for example, the traveling trajectory duplication unit 135 generates duplicate traveling trajectories 703 and 704 by translating the traveling trajectory 505 to positions where the traveling trajectory 505 contacts the traveling trajectories 506 and 507.

[0065] Returning to Fig. 3, if data indicating a duplicated travel trajectory is generated in step S14, the process proceeds to step S15, where the road shape estimation unit 136 estimates the shape of the road within the intersection based on the data indicating the duplicated travel trajectory generated by the travel trajectory duplication unit 135. The road shape estimation unit 136 estimates the shape of the road within the intersection from a plurality of travel trajectories made up of the duplicated travel trajectory and the travel trajectory within the intersection.

[0066] For example, in Fig. 8, the road shape estimation unit 136 estimates the shape of the road within the intersection from duplicated travel trajectories 701 and 702 and travel trajectory 504 within the intersection. Also, in Fig. 9, for example, the road shape estimation unit 136 estimates the shape of the road within the intersection from duplicated travel trajectories 703 and 704 and travel trajectories 505, 506, and 507 within the intersection.

[0067] [Effects of this embodiment] As described above, the lane estimation method and device according to this embodiment acquire data indicating the position and direction of each of multiple road arrow markings before an intersection. Data indicating the travel trajectory of a vehicle traveling through the intersection is acquired. The distance in the lane width direction from the travel trajectory to each of the multiple road arrow markings is calculated. The destination of the travel trajectory is determined based on the direction of a reference road arrow marking, which is a road arrow marking whose distance from the travel trajectory to the road arrow marking is less than a first threshold. Data indicating a duplicate travel trajectory is generated by translating the travel trajectory to a position of a road arrow marking that indicates the same direction as the destination of the travel trajectory and is different from the reference road arrow marking. The shape of the lane within the intersection is estimated based on the data indicating the duplicate travel trajectory.

[0068] The destination of a road arrow marking whose lane width direction distance from the vehicle's driving trajectory is less than a threshold value can be determined to be the destination of the driving trajectory. A duplicate driving trajectory is generated by duplicating the driving trajectory at the position of a road arrow marking that indicates the same direction as the driving trajectory destination and is different from the reference road arrow marking, and the shape of the road within the intersection can be estimated based on the duplicate driving trajectory. This makes it possible to estimate the shape of the road even in areas of the intersection where no driving trajectory has been acquired.

[0069] In this embodiment, the reference road arrow marking is, among the multiple road arrow markings, the road arrow marking whose distance from the travel path to the road arrow marking is less than the first threshold and is the shortest.

[0070] The destination of the road arrow marking that is the shortest distance from the vehicle's travel path in the lane width direction and less than the threshold value is determined to be the destination of the travel path. This makes it possible to accurately determine the destination of the travel path regardless of the shape of the travel path or the shape of the intersection.

[0071] In this embodiment, a reference line segment passing through the center of the lane width direction is set for each of the multiple road arrow markings. If it is possible to draw a perpendicular line from the travel trajectory to the reference line segment, the distance in the lane width direction between the travel trajectory and the reference line segment at which the perpendicular line is shortest is calculated as the distance in the lane width direction from the travel trajectory to the road arrow marking.

[0072] The direction of the road arrow marking where the distance in the lane width direction between the reference line segment and the vehicle's travel path, which is the shortest perpendicular line drawn from the vehicle's travel path to the reference line segment passing through the lane width center of the road arrow marking, is less than a threshold, can be determined as the destination of the travel path. This makes it possible to accurately determine the destination of the travel path regardless of the shape of the travel path or the shape of the intersection.

[0073] In this embodiment, a reference line segment passing through the center position in the lane width direction is set for each of the multiple road arrow markings. If it is impossible to draw a perpendicular line from the travel trajectory to the reference line segment, the travel trajectory is extended toward the reference line segment. The distance in the lane width direction between the extended travel trajectory and the reference line segment, where the perpendicular line drawn from the extended travel trajectory to the reference line segment is the shortest, is calculated as the distance in the lane width direction from the travel trajectory to the road arrow marking.

[0074] The destination of the road arrow marking can be determined as the destination of the driving trajectory when the distance in the lane width direction between the extended driving trajectory of the vehicle and the reference line segment is less than a threshold value at the point where the perpendicular line drawn from the extended driving trajectory to the reference line segment passing through the center position of the lane width direction of the road arrow marking is the shortest. This makes it possible to accurately determine the destination of the driving trajectory, even for short driving trajectories detected partway through an intersection, regardless of the shape of the driving trajectory or the shape of the intersection.

[0075] In this embodiment, a first angle formed by the extended travel trajectory and the reference line segment is calculated. If the first angle is less than a second threshold, the destination of the travel trajectory is determined based on the direction of a reference road arrow marking, which is a road arrow marking whose distance in the lane width direction from the travel trajectory to the reference road arrow marking is less than the first threshold.

[0076] The direction of the road arrow marking where the angle between the extended travel path and the reference line segment passing through the lane width center position of the road arrow marking is less than a threshold value can be determined as the destination of the travel path. This makes it possible to more accurately determine the destination of a short travel path detected partway through an intersection, regardless of the shape of the travel path or the shape of the intersection.

[0077] In this embodiment, when there are multiple directions indicated by the reference road arrow marking, the curvature of the travel path is calculated, and the destination of the travel path is determined based on the curvature.

[0078] When the reference road arrow marking indicates multiple directions, the destination of the traveled path is determined based on the curvature of the traveled path, thereby making it possible to identify a single destination of the traveled path.

[0079] In this embodiment, a reference line segment passing through the center position in the lane width direction is set for each of the multiple road arrow markings. If it is impossible to draw a perpendicular line from the travel trajectory to the reference line segment, the travel trajectory is translated in the lane width direction, and it is determined whether the translated travel trajectory intersects with another travel trajectory. If the translated travel trajectory intersects with another travel trajectory, a second angle formed between the translated travel trajectory and the other travel trajectory is calculated. If the second angle is less than a third threshold, the travel trajectory is translated to a position where it intersects with the other travel trajectory, and data indicating a duplicate travel trajectory is generated by duplicating the travel trajectory.

[0080] The system duplicates the travel path that does not touch the arrow markings by translating it to a position where it intersects with other travel paths, so even short travel paths can be duplicated. Based on the duplicated travel path, the route within the intersection can be estimated.

[0081] Note that, when generating the duplicated traveling trajectory, the traveling trajectory duplication unit 135 may adjust the turning radius of the duplicated traveling trajectory by the amount of translation of the traveling trajectory. For example, in FIG. 10A , when arrow markings Y11 and Y12 are present before an intersection and another vehicle V is traveling through the intersection, the arrow marking Y11 is identified as the reference arrow marking and the destination of the traveling trajectory 508 of the other vehicle V is determined to be "left turn." Then, the traveling trajectory 508 is translated to the position of the arrow marking Y12 and duplicated to generate a duplicated traveling trajectory 705. In this case, the traveling trajectory duplication unit 135 may adjust the turning radius of the duplicated traveling trajectory 705 by the amount of translation of the traveling trajectory 508 to the position of the arrow marking Y12, so as to increase the curvature of the traveling trajectory 508 and decrease the radius of the traveling trajectory 508.

[0082] 10B , for example, when arrow markings Y13 and Y14 are present before an intersection and another vehicle V is traveling through the intersection, arrow marking Y13 is identified as the reference arrow marking and the destination of travel trajectory 509 of the other vehicle V is determined to be "right turn." Then, travel trajectory 509 is translated to the position of arrow marking Y14 and a duplicated travel trajectory 706 is generated. In this case, the travel trajectory duplication unit 135 adjusts the turning radius of the duplicated travel trajectory 706 so as to reduce the curvature of travel trajectory 509 and increase the radius of travel trajectory 509 by the amount of translation of travel trajectory 509 to the position of arrow marking Y14.

[0083] By increasing or decreasing the turning radius of the travel path by the amount of movement during duplication, it is possible to duplicate a travel path that does not intersect with adjacent roads.

[0084] Although the embodiments of the present invention have been described above, the descriptions and drawings that form part of this disclosure should not be understood to limit the present invention. Various alternative embodiments, examples, and operating techniques will become apparent to those skilled in the art from this disclosure. [Explanation of symbols]

[0085] 1 Track estimation device 501~509 Running track 701~706 Replica driving track D1~D3 distance Y, Y1~Y14 Road arrow markings (arrow markings) V, V1~V2 vehicles (other vehicles)

Claims

1. A method for estimating a route within an intersection using a route estimation device acquire data indicating the position and direction of each of the plurality of road arrow markings before the intersection; acquiring data indicating a travel path of a vehicle traveling through the intersection; Calculating a distance in a lane width direction from the travel path to each of the plurality of road arrow markings; determining a destination of the travel path based on a direction of a reference road arrow marking, which is the road arrow marking whose distance is less than a first threshold value; generating data indicating a duplicated travel locus obtained by translating the travel locus to a position of the road arrow marking that indicates the same direction as the destination of the travel locus and is different from the reference road arrow marking; A travel path estimation method comprising estimating the shape of a travel path within the intersection based on data indicating the replicated travel path.

2. The reference road arrow marking is a road arrow marking, among the plurality of road arrow markings, for which the distance is less than the first threshold and is the shortest. The method for estimating a travel path according to claim 1 .

3. A reference line segment passing through a center position in a lane width direction is set for each of the plurality of road arrow markings; If it is possible to draw a perpendicular line from the travel trajectory to the reference line segment, the distance in the lane width direction between the travel trajectory and the reference line segment at which the perpendicular line is shortest is calculated as the distance in the lane width direction from the travel trajectory to the road arrow marking.

3. The method for estimating a travel path according to claim 1 or 2.

4. A reference line segment passing through a center position in a lane width direction is set for each of the plurality of road arrow markings; If it is impossible to draw a perpendicular line from the travel path to the reference line segment, the travel path is extended toward the reference line segment; The distance in the lane width direction between the extended travel path and the reference line segment, where the perpendicular line drawn from the extended travel path to the reference line segment is the shortest, is calculated as the distance in the lane width direction from the travel path to the road arrow marking.

3. The method for estimating a travel path according to claim 1 or 2.

5. Calculating a first angle between the extended travel path and the reference line segment; If the first angle is less than a second threshold, the destination of the travel path is determined based on the direction of the reference road arrow marking, which is the road arrow marking whose distance is less than the first threshold.

5. The method for estimating a travel path according to claim 4.

6. If there are a plurality of directions indicated by the reference road arrow markings, a curvature of the travel path is calculated; The destination of the travel path is determined based on the curvature.

3. The method for estimating a travel path according to claim 1 or 2.

7. The turning radius of the replicated travel path is adjusted by the amount of translation of the travel path.

3. The method for estimating a travel path according to claim 1 or 2.

8. A reference line segment passing through a center position in a lane width direction is set for each of the plurality of road arrow markings; If it is impossible to draw a perpendicular line from the travel path to the reference line segment, the travel path is translated in the lane width direction; determining whether the translated travel path touches another travel path; When the translated travel trajectory is in contact with the other travel trajectory, a second angle formed between the translated travel trajectory and the other travel trajectory is calculated; If the second angle is less than a third threshold, the travel path is translated to a position where it contacts the other travel path, and data indicating the duplicated travel path obtained by duplicating the travel path is generated.

3. The method for estimating a travel path according to claim 1 or 2.

9. A travel path estimation device including a control unit that estimates a travel path within an intersection, The control unit acquire data indicating the position and direction of each of the plurality of road arrow markings before the intersection; acquiring data indicating a travel path of a vehicle traveling through the intersection; Calculating a distance in a lane width direction from the travel path to each of the plurality of road arrow markings; determining a destination of the travel path based on a direction of a reference road arrow marking, which is the road arrow marking whose distance is less than a first threshold value; generating data indicating a duplicated travel locus obtained by translating the travel locus to a position of the road arrow marking that indicates the same direction as the destination of the travel locus and is different from the reference road arrow marking; A travel path estimation device that estimates the shape of a travel path within the intersection based on data indicating the replicated travel path.

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