JP2021071515A - Map generation device, method for generating map, and map generation program - Google Patents

Abstract

To allow proper determination as to whether or not, a division line is a center line of a road.SOLUTION: In a map generation device 10, a division line specification unit 24 specifies a division line of a road from measurement information of the road obtained by a measuring device such as a MMS (a mobile mapping system). A stop line specification unit 25 specifies a stop line of the road from the measurement information. A center line specification unit 26 specifies, as a road center line, one of the division lines specified by the division line specification unit 24 that is closer to a reference direction of the stop line specified by the stop line specification unit 25.SELECTED DRAWING: Figure 1

Description

The present invention relates to a technique for identifying a roadway center line when generating map information from measurement information.

In recent years, the development of self-driving cars has been promoted. In order to realize autonomous driving, high-precision map information is required in addition to various sensors such as cameras and laser radars attached to autonomous vehicles. As a method of generating this highly accurate map information, by running a measurement vehicle called MMS (Mobile Mapping System), 3D point cloud information such as road surface and roadside equipment is acquired, and 3D point cloud information is obtained. A method of generating map information based on the above has been considered (see Patent Document 1).

The information acquired by MMS is point cloud information holding three-dimensional position information, not map information. Therefore, a plotting process for generating map information from point cloud information is required.
When a wide range of map information is manually generated, the point cloud information to be processed becomes enormous, so that the work cost becomes enormous. In particular, the work cost of creating lane marking information, which is map information required for the realization of autonomous driving, is a problem because it is a feature that always exists along the road. As the lane marking information, not only the position information of where the line is drawn but also the attribute information such as whether it is the center line of the roadway for separating from the oncoming lane is required. The center line of the roadway is also called the center line and the upper and lower dividing lines. The attribute information includes not only information on the line type such as whether it is the center line of the roadway, but also information such as the line color, the line width, and the distinction between a solid line and a broken line.

If you drive on the road information beyond the center line of the road, you may collide head-on with an oncoming vehicle. Therefore, where the center line of the roadway is is important information for autonomous driving.

Further, when a map is generated using information acquired by a measurement vehicle such as MMS, it is often the case that map information is generated by separately measuring and traveling for each of the upper and lower lanes on a two-way road. This is because if the map information of the oncoming lane is generated, the accuracy of the map information generated due to the influence of the distance and the shielding may deteriorate.
At this time, when the map information is generated from the measurement information obtained by measuring the up lane, the down lane is excluded from the generation target of the map information. However, if the center line of the roadway cannot be determined, it becomes impossible to determine where the generation target is not included. Therefore, it is important to know where the center line of the roadway is from the viewpoint of efficiency of map generation work.

Japanese Unexamined Patent Publication No. 2010-191066

Conventionally, there has been no effective method for determining whether the lane marking is the center line of the roadway.
An object of the present invention is to make it possible to appropriately determine whether or not a lane marking is a roadway center line.

The map generator according to the present invention is
From the road measurement information obtained by the measuring device, the lane marking part that identifies the lane marking of the road and the lane marking section
A stop line identification unit that identifies the stop line of the road from the measurement information,
From the lane markings specified by the lane markings, the lane markings include a center line specifying portion that identifies the road center line based on the stop line identified by the stop line locating section.

In the present invention, the roadway center line is specified based on the stop line. This makes it possible to appropriately determine whether or not the lane marking is the center line of the roadway. As a result, it is possible to reduce the work cost required for map generation.

The block diagram of the map generation apparatus 10 which concerns on Embodiment 1. FIG. FIG. 5 is a flowchart showing the overall operation of the map generator 10 according to the first embodiment. The flowchart of the process which specifies the roadway center line in the map generation process which concerns on Embodiment 1. The explanatory view of the process which specifies the stop line intersecting with the traveling locus which concerns on Embodiment 1. FIG. The explanatory view of the process which identifies the roadway center line from the stop line which concerns on Embodiment 1. FIG. The block diagram of the map generation apparatus 10 which concerns on modification 3.

Embodiment 1.
*** Explanation of configuration ***
The configuration of the map generation device 10 according to the first embodiment will be described with reference to FIG.
The map generator 10 is a computer.
The map generator 10 includes hardware such as a processor 11, a memory 12, a storage 13, and a communication interface 14. The processor 11 is connected to other hardware via a signal line and controls these other hardware.

The processor 11 is an IC (Integrated Circuit) that performs processing. Specific examples of the processor 11 are a CPU (Central Processing Unit), a DSP (Digital Signal Processor), and a GPU (Graphics Processing Unit).

The memory 12 is a storage device that temporarily stores information. Specific examples of the memory 12 are SRAM (Static Random Access Memory) and DRAM (Dynamic Random Access Memory).

The storage 13 is a storage device for storing information. As a specific example, the storage 13 is an HDD (Hard Disk Drive). The storage 13 includes SD (registered trademark, Secure Digital) memory card, CF (CompactFlash, registered trademark), NAND flash, flexible disk, optical disk, compact disk, Blu-ray (registered trademark) disk, DVD (Digital Versaille Disk), and the like. It may be a portable recording medium.

The communication interface 14 is an interface for communicating with an external device. As a specific example, the communication interface 14 is a port of Ethernet (registered trademark), USB (Universal Serial Bus), HDMI (registered trademark, High-Definition Multimedia Interface).
The map generation device 10 is connected to devices such as an input device 31, a display device 32, and a reading device 33 via a communication interface 14. The input device 31 is a device for inputting information, and specific examples thereof are a keyboard and a mouse. The display device 32 is a device for displaying information, and as a specific example, it is an LCD (Liquid Crystal Display). The reading device 33 is a device that reads information from a storage medium, and a specific example is a DVD drive. Further, the map generator 10 may be connected to a transmission line such as a LAN (Local Area Network) via the communication interface 14.

The map generation device 10 includes a measurement information acquisition unit 21, a map generation unit 22, and a map transmission unit 23 as functional components. The map generation unit 22 includes a division line identification unit 24, a stop line identification unit 25, and a center line identification unit 26 as functional components. The functions of each functional component of the map generator 10 are realized by software.
The storage 13 stores a program that realizes the functions of each functional component of the map generator 10. This program is read into the memory 12 by the processor 11 and executed by the processor 11. As a result, the functions of each functional component of the map generation device 10 are realized.

In FIG. 1, only one processor 11 was shown. However, the number of processors 11 may be plural, and the plurality of processors 11 may execute programs that realize each function in cooperation with each other.

*** Explanation of operation ***
The operation of the map generation device 10 according to the first embodiment will be described with reference to FIGS. 2 to 5.
The operation procedure of the map generation device 10 according to the first embodiment corresponds to the map generation method according to the first embodiment. Further, the program that realizes the operation of the map generation device 10 according to the first embodiment corresponds to the map generation program according to the first embodiment.

The overall operation of the map generator 10 according to the first embodiment will be described with reference to FIG.
(Step S1: Measurement information acquisition process)
The measurement information acquisition unit 21 acquires the measurement information of the road obtained by the measuring device.
As a specific example, the measurement information acquisition unit 21 acquires measurement information from the measurement device via a transmission line. Alternatively, the measurement information acquisition unit 21 may acquire the measurement information by reading the measurement information stored in the storage medium such as a DVD by the reading device 33.
In the first embodiment, the measuring device is a measuring vehicle equipped with a sensor such as a laser radar. Further, in the first embodiment, the measurement information is point cloud information having three-dimensional position information indicating the latitude, longitude, and height of the road surface and equipment on the side of the road.

(Step S2: Map generation process)
The map generation unit 22 generates map information from the measurement information acquired in step S1.
Specifically, the map generation unit 22 identifies the constituent points constituting the feature such as the road division line and the shoulder edge of the road from the point cloud information which is the measurement information. Since each point in the point cloud information has three-dimensional position information, the three-dimensional position of the feature is specified when the constituent points constituting the feature are specified. Then, the map generation unit 22 specifies the attribute information of each feature from the position and size of the constituent points constituting the feature on the road. As a result, the map generation unit 22 generates map information indicating the position and attribute information of each object.
At this time, the map generation unit 22 may receive an operation from the input device 31 via the communication interface 14 and edit the map information. That is, the map generation unit 22 may edit the map information based on a manual editing operation.

(Step S3: Map transmission process)
The map transmission unit 23 transmits the map information generated in step S2 to the display device 32 via the communication interface 14 to display the map information. The map transmission unit 23 may transmit map information not only to the display device 32 but also to other devices such as a user's terminal.

With reference to FIG. 3, a process of specifying the roadway center line in the map generation process according to the first embodiment will be described.
(Step S21: Compartment line identification process)
The lane marking identification unit 24 identifies a sequence of points that are constituent points constituting the lane marking from the distribution information of the reflection intensity of each point of the point cloud information that is the measurement information acquired in step S1. Here, the lane marking unit 24 specifies a lane center line, a lane boundary line, and a lane outer line as lane markings. The lane marking unit 24 may also specify other lane markings such as a headrace zone.
Specifically, the lane marking identification unit 24 divides the point cloud information into a plurality of plate-shaped cross-sectional regions perpendicular to the traveling direction of the measurement vehicle. The lane marking identification unit 24 specifies a point at the center of gravity of a portion where the reflection intensity is higher than a certain value or more with respect to the surroundings as a point representing the lane marking. The lane marking unit 24 clusters the points representing the lane markings identified from each cross-sectional area to identify a sequence of points constituting each one or more lane markings existing on the road. Clustering is the grouping of constituent points that exist in the vicinity. As a result, the lane marking unit 24 identifies the three-dimensional position of each of the one or more lane markings existing on the road.

(Step S22: Stop line identification process)
The stop line specifying unit 25 identifies the constituent points constituting the stop line from the distribution information of the reflection intensity of each point of the point cloud information which is the measurement information acquired in step S1.
Specifically, the stop line specifying unit 25 excludes points near the marking line specified in step S21 from the points included in the point cloud information, and extracts points having a reflection intensity higher than the threshold value from the remaining points. .. The stop line identification unit 25 clusters the extracted points. The stop line identification unit 25 calculates a rectangle that includes a cluster that is a collection of clustered points. When the calculated rectangle size satisfies the condition of the stop line, the stop line specifying unit 25 determines the rectangle as a stop line, and specifies the positions of the four corners of the rectangle from the positions of the points forming the cluster.
The stop line specifying unit 25 may use a preset value as the threshold value of the reflection intensity, or may use a value according to the distribution state of the reflection intensity at each point. Further, the stop line specifying unit 25 may extract points where the reflection intensity is higher than a certain value or more than the surroundings, instead of extracting points where the reflection intensity is higher than the threshold value.

(Step S23: Center line identification process)
The center line specifying unit 26 identifies the road center line from the lane marking line specified in step S21 based on the stop line specified in step S22.
Specifically, as shown in FIG. 4, the center line specifying unit 26 identifies a stop line that intersects the traveling locus of the measuring vehicle, which is a measuring device, among the stop lines specified in step S22. As a result, the central line specifying unit 26 identifies the stop line in the lane for which map information is generated in the case of two-way traffic. In FIG. 4, among the stop lines 41A to 41C, the stop line 41A and the stop line 41B are specified as stop lines that intersect the traveling locus.
As shown in FIG. 5, the center line specifying unit 26 specifies a point on the reference direction side on the front side of the measurement vehicle in the traveling direction as a reference point 42 among the rectangles indicating the stop lines intersecting the traveling locus. Then, the center line specifying unit 26 identifies the lane marking closest to the reference point 42 as the roadway center line 43.
Here, the reference direction is right in the case of left-hand traffic and left in the case of right-hand traffic. That is, in the case of left-hand traffic, the center line identification portion 26 specifies the point at the front corner on the right side as the reference point among the rectangles indicating the stop lines intersecting the traveling locus, and the division line closest to the reference point 42. Is specified as the roadway central line 43.

*** Effect of Embodiment 1 ***
As described above, the map generation device 10 according to the first embodiment identifies the roadway center line based on the stop line. This makes it possible to appropriately determine whether or not the lane marking is the center line of the roadway without performing determination processing such as determining whether the lane marking is a solid line or a broken line and determining the presence or absence of a median strip. As a result, it is possible to reduce the work cost required for map generation.

*** Other configurations ***
<Modification example 1>
In the first embodiment, the measuring device is a measuring vehicle. However, the measuring device is not limited to the measuring vehicle, and may be a device mounted on an aircraft, a satellite, or the like. In this case, instead of the traveling locus of the measurement vehicle, the traveling locus of the vehicle traveling in the lane to be measured may be used.

<Modification 2>
In the first embodiment, the measurement information is point cloud information. However, the measurement information may be road image data obtained by the photographing device.
In this case, the lane marking unit 24 may specify the lane marking from the luminance distribution of the image data. Specifically, the lane marking identification unit 24 may specify a point at the center of gravity of a portion where the brightness of the image data is higher than a certain value in the width direction of the road as a point representing the lane marking. Then, the lane marking identification unit 24 may cluster points representing the lane markings specified from each cross-sectional area to specify a sequence of points constituting each of one or more lane markings existing on the road.
Further, the stop line specifying unit 25 may specify the stop line from the luminance distribution of the image data. Specifically, the stop line specifying unit 25 may exclude a region near the lane marking and extract a region having a brightness higher than the threshold value from the remaining region. The stop line specifying unit 25 may calculate a rectangle including the extracted region, and if the size of the rectangle satisfies the condition of the stop line, determine the rectangle as the stop line.

<Modification example 3>
In the first embodiment, each functional component is realized by software. However, as a modification 3, each functional component may be realized by hardware. The difference between the third modification and the first embodiment will be described.

The configuration of the map generation device 10 according to the third modification will be described with reference to FIG.
When each functional component is realized by hardware, the map generator 10 includes an electronic circuit 15 instead of the processor 11, the memory 12, and the storage 13. The electronic circuit 15 is a dedicated circuit that realizes the functions of each functional component, the memory 12, and the storage 13.

Examples of the electronic circuit 15 include a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, a logic IC, a GA (Gate Array), an ASIC (Application Specific Integrated Circuit), and an FPGA (Field-Programmable Gate Array). is assumed.
Each functional component may be realized by one electronic circuit 15, or each functional component may be distributed and realized by a plurality of electronic circuits 15.

<Modification example 4>
As a modification 4, some functional components may be realized by hardware, and other functional components may be realized by software.

The processor 11, the memory 12, the storage 13, and the electronic circuit 15 are referred to as processing circuits. That is, the function of each functional component is realized by the processing circuit.

The embodiments and modifications of the present invention have been described above. Some of these embodiments and modifications may be combined and carried out. In addition, any one or several may be partially carried out. The present invention is not limited to the above embodiments and modifications, and various modifications can be made as needed.

10 map generator, 11 processor, 12 memory, 13 storage, 14 communication interface, 15 electronic circuit, 21 measurement information acquisition unit, 22 map generator, 23 map transmitter, 24 lane marking unit, 25 stop line identification unit, 26 Central line identification unit, 31 Input device, 32 Display device, 33 Reader, 41 Stop line, 42 Reference point, 43 Road central line.

Claims (6)

From the road measurement information obtained by the measuring device, the lane marking part that identifies the lane marking of the road and the lane marking section
A stop line identification unit that identifies the stop line of the road from the measurement information,
A map generation device including a center line specifying unit that specifies a roadway center line based on the stop line specified by the stop line specifying unit from the division line specified by the division line specifying unit. The measuring device is a measuring vehicle.
The measurement information is information obtained while the vehicle is traveling, and is
The central line specifying unit claims to specify a lane marking line near the reference direction side of the stop line that intersects the traveling locus of the measuring vehicle among the stop lines specified by the stop line specifying unit as the road center line. The map generator according to 1. The stop line identification unit identifies a rectangle indicating the stop line and determines the rectangle.
According to claim 1 or 2, the center line specifying portion specifies a point on the reference direction side as a reference point in a rectangle indicating the stop line, and specifies a lane marking closest to the reference point as a roadway center line. The map generator described. The map generation device according to any one of claims 1 to 3, wherein the center line specifying unit specifies a lane marking line closest to the right side of the stop line as a road center line. The lane marking unit identifies the lane marking of the road from the measurement information of the road obtained by the measuring device.
The stop line identification unit identifies the stop line of the road from the measurement information,
A map generation method in which the center line specifying unit specifies, among the specified lane markings, a lane marking that is closer to the reference direction side of the specified stop line as the road markings. From the road measurement information obtained by the measuring device, the lane marking process for identifying the lane marking of the road and the lane marking process.
Stop line identification processing that identifies the stop line of the road from the measurement information,
Of the lane markings specified by the lane marking process, a map that performs a center line specifying process for identifying a lane marking near the reference direction side of the stop line specified by the stop line specifying process as a road markings. A map generator that makes a computer function as a generator.

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