Map information generation device

Abstract

This invention provides a map information generation device that can generate more detailed map information about lanes based on road link information for route guidance, which includes information about the number of lanes. [Solution] The system is configured to acquire branching points P, which are the starting or ending points of parallel sections where roads run parallel, targeting branching points where one road branches off to form multiple parallel roads, or confluence points where multiple parallel roads merge to form one road. Based on road link information for route guidance, which includes information on the number of lanes, and the branching points P, the system generates virtual lanes 51 as lane information that specifies the position and shape of each lane included in the road at the branching point or confluence point.

Description

Technical Field

[0001] The present invention relates to a map information generation device that generates map information.

Background Art

[0002] Conventionally, there are known driving support devices that perform various driving supports such as assisting the driving operation of a vehicle in various scenes, performing part or all of the driving operation on behalf of the driver, and guiding information for performing the driving operation. Here, when performing the above driving support, in order to perform more accurate support, it is necessary to grasp how the lane markings and lanes are arranged on the road on which the vehicle is traveling, and detailed map information is required to grasp them.

[0003] For example, conventionally, there is map information having the number of lanes of a road as link information. Such map information can be used for support even when driving on a straight road without branches or changes in the number of lanes, but on the other hand, it has been difficult to perform accurate support using only conventional map information, for example, around the point where a road branches or merges. Therefore, for example, Japanese Patent Application Laid-Open No. 2008-101972 proposes a technique that enables more accurate map matching by generating a virtual link that is a line through which a vehicle passes within an intersection where lanes are not clearly divided.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the aforementioned Patent Document 1, the lines that vehicles travel through an intersection are clarified by setting up virtual links within the intersection based on the number of lanes of roads connecting in the intersecting direction and the traffic divisions for each lane. However, at branching points where one road branches into multiple parallel roads, or at merging points where multiple parallel roads merge into one, the lane connections are more complex than at normal intersections, and there are also parallel road sections (sections where vehicles can move back and forth between two parallel roads). Therefore, it was difficult to determine how the lanes actually exist using the same technology as in Patent Document 1.

[0006] On the other hand, it is possible to create more detailed map information by having people actually verify the locations on-site, but it has been practically difficult to accurately create a database of such detailed map information covering all roads nationwide.

[0007] The present invention was made to solve the aforementioned problems of the conventional method, and aims to provide a map information generation device that can generate more detailed map information regarding lanes based on road link information for route guidance, including information regarding the number of lanes, with respect to the branching and merging points mentioned above. [Means for solving the problem]

[0008] To achieve the above objective, the map information generation device according to the present invention includes: a location information acquisition means for acquiring location information that identifies the location of the point where a parallel section of roads begins or ends, targeting branching points where one road branches off to form multiple parallel roads, or merging points where multiple parallel roads merge to form one road; and an information generation means for generating lane information that identifies the position and shape of each lane included in the road at the branching point or merging point, based on road link information for route guidance including information on the number of lanes and the location information. Furthermore, a "parallel section" refers to a section where two or more roads traveling in the same direction are adjacent to each other and vehicles can travel back and forth between them. [Effects of the Invention]

[0009] According to the map information generation device of the present invention having the above configuration, it is possible to generate more detailed map information regarding lanes at branching points where one road branches off to form multiple parallel roads, or at merging points where multiple parallel roads merge to form one road, based on road link information for route guidance that includes information regarding the number of lanes. As a result, it becomes possible to provide more appropriate driving assistance at branching points and merging points. [Brief explanation of the drawing]

[0010] [Figure 1] This is a block diagram showing the navigation device according to this embodiment. [Figure 2] This diagram shows the branching point and the junction point P located at the branching point. [Figure 3] This diagram shows the confluence point and the branching confluence point P located at the confluence point. [Figure 4] This is a flowchart of the map information generation processing program according to this embodiment. [Figure 5] This diagram illustrates a method for identifying parallel sections at branching points. [Figure 6] This diagram illustrates a method for identifying parallel sections at merging points. [Figure 7] This diagram illustrates how virtual lanes are generated at branching points. [Figure 8] This diagram illustrates how virtual lanes are generated at branching points. [Figure 9] This diagram illustrates how virtual lanes are generated at merging points. [Figure 10] This diagram illustrates how virtual lanes are generated at merging points. [Figure 11] This figure shows an example of a road image displayed on an LCD screen. [Figure 12] This diagram illustrates how virtual lanes are generated at other branching points. [Modes for carrying out the invention]

[0011] Hereinafter, an embodiment of the map information generation device according to the present invention, implemented in a navigation device 1, will be described in detail with reference to the drawings. First, the schematic configuration of the navigation device 1 according to this embodiment will be described using Figure 1. Figure 1 is a block diagram showing the navigation device 1 according to this embodiment. In the following embodiment, an example in which the navigation device functions as a map information generation device will be described, but other in-vehicle devices or information terminals connected to the vehicle may also function as map information generation devices, and furthermore, multiple in-vehicle devices or a combination of in-vehicle devices and an external server may also function as a map information generation device.

[0012] Here, the navigation device 1 is an in-vehicle device that is mounted in the vehicle and displays a map of the area around the vehicle's current position based on map information held by the navigation device 1 or map information acquired from an external source, allows the user to input a destination, displays the vehicle's current position on the map image, and provides driving guidance along a set guidance route. For example, if the vehicle is capable of assisted driving through automated driving assistance, it is also possible to generate various support information related to automated driving assistance. Examples of support information include the recommended driving trajectory for the vehicle and a speed plan indicating the vehicle speed when driving.

[0013] As shown in FIG. 1, the navigation device 1 according to the present embodiment includes a current position detection unit 11 that detects the current position of a vehicle on which the navigation device 1 is mounted, a data recording unit 12 in which various data are recorded, a navigation ECU 13 that performs various arithmetic processes based on the input information, an operation unit 14 that receives operations from the user, a liquid crystal display 15 that displays a road image or the like showing the road shape around the vehicle, a speaker 16 that outputs voice guidance regarding route guidance, a DVD drive 17 that reads a DVD which is a storage medium, and a communication module 18 that communicates with an information center such as a probe center or a VICS (registered trademark: Vehicle Information and Communication System) center. Further, the navigation device 1 is connected via an in-vehicle network such as CAN to various sensors such as an outside camera 19 and an ultrasonic sensor 20 installed in the vehicle on which the navigation device 1 is mounted. Furthermore, it is also connected in a bidirectionally communicable manner to a vehicle control ECU 21 that performs various controls on the vehicle on which the navigation device 1 is mounted. Also, various operation buttons 22 mounted on the vehicle such as an automatic driving start button are connected thereto.

[0014] Here, the vehicle on which the navigation device 1 is mounted is a vehicle capable of assisted driving by automatic driving support in which the vehicle automatically travels along a preset route or path without depending on the driving operation of the user, in addition to manual driving in which the vehicle travels based on the driving operation of the user.

[0015] In addition, the automatic driving support may be performed for all road sections, or it may be configured to be performed only while the vehicle is traveling on a specific road section (for example, an expressway where a gate (regardless of manned or unmanned, toll or free) is provided at the boundary). In the following description, the automatic driving sections where the automatic driving support of the vehicle is performed include not only all road sections including general roads and expressways but also parking lots, and it will be described that the automatic driving support is basically performed from the start to the end of the vehicle's travel (until the vehicle is parked). However, when the vehicle is traveling on an automatic driving section, the automatic driving support is not necessarily performed. It is desirable to perform it only when the user selects to perform the automatic driving support (for example, turns on the automatic driving start button) and it is determined that it is possible to make the vehicle travel by the automatic driving support. Also, it is possible to switch to manual driving at the driver's discretion while the vehicle is traveling under automatic driving support.

[0016] In the vehicle control in the automatic driving support, for example, the current position of the vehicle, the lane in which the vehicle is traveling, and the positions of surrounding obstacles are detected at any time, and the vehicle control such as steering, drive source, and brake is automatically performed so that the vehicle travels at a speed according to the speed plan generated along the travel trajectory or the planned travel route (guidance route) generated by the navigation device 1. In addition, in the assisted driving by the automatic driving support of this embodiment, lane changes, merging operations, and right / left turn operations are also automatically performed by the above automatic driving support. However, for driving that requires special operations such as lane changes, merging operations, and right / left turn operations, it may be configured to be performed manually instead of by automatic driving support. On the other hand, it may be a vehicle that can only be driven manually.

[0017] Next, each component of the navigation device 1 will be described in order. The current position detection unit 11 consists of a GPS 25, a vehicle speed sensor 26, a steering sensor 27, a gyro sensor 28, etc., and is capable of detecting the current position, direction, vehicle speed, current time, etc. In particular, the vehicle speed sensor 26 is a sensor for detecting the distance traveled and vehicle speed of the vehicle, and generates pulses in accordance with the rotation of the vehicle's drive wheels and outputs the pulse signal to the navigation ECU 13. The navigation ECU 13 then calculates the rotation speed of the drive wheels and the distance traveled by counting the generated pulses. It should be noted that the navigation device 1 does not need to be equipped with all four types of sensors mentioned above, and the navigation device 1 may be configured to be equipped with only one or more of these types of sensors.

[0018] Furthermore, the data recording unit 12 includes a hard disk (not shown) as an external storage device and recording medium, and a recording head (not shown) which is a driver for reading map information DB31, generated map information DB32, predetermined programs, etc., recorded on the hard disk, and writing predetermined data to the hard disk. The data recording unit 12 may be configured using a memory card or an optical disc such as a CD or DVD instead of a hard disk. Alternatively, the map information DB31 may be stored on an external server and acquired by the navigation device 1 via communication.

[0019] Here, the map information DB31 is a storage means that stores simplified map information, including road link information used for route search processing and route guidance to a destination in the navigation device 1. This simplified map information includes, for example, link data (road link information for route guidance) 33 related to roads (links), node data 34 related to node points, branching point data 35 related to branching points, road image data 36 for displaying road images described later, search data used for processing related to route search and modification, facility data related to facilities, map display data for displaying maps, intersection data related to each intersection, search data for searching for locations, etc.

[0020] Furthermore, the link data 33 includes data for each link constituting the road, such as the width of the road to which the link belongs, the slope, cant, bank, road surface condition, merging sections, road structure, presence or absence of shoulder space, number of lanes, points where the number of lanes decreases, points where the width narrows, and level crossings. For corners, it includes data representing the radius of curvature, intersections, T-junctions, corner entrances and exits. For road attributes, it includes data representing downhill roads, uphill roads, etc. For road types, it includes data representing general roads such as national highways, prefectural roads, and narrow streets, as well as toll roads such as expressways, urban expressways, motorways, general toll roads, and toll bridges. In particular, in this embodiment, in addition to the number of lanes on the road, it also includes information that identifies the traffic divisions for the direction of travel for each lane and the connections between roads (specifically, for example, the correspondence between the lanes included in the road before passing and the lanes included in the road after passing at points where the number of lanes increases or decreases or at intersections where lanes are interrupted), as well as the speed limit set for the road. Furthermore, the information includes details that identify whether the links forming the merging and branching points described later are part of the main road or a side road. On the other hand, it does not include details that identify the specific location and shape of road lanes and markings (how lanes and markings are arranged on the road), nor the lane width.

[0021] Furthermore, the node data 34 records data such as the coordinates (positions) of node points set at predetermined distances according to the radius of curvature, etc., for actual road junctions (including intersections, T-junctions, etc.), node attributes indicating whether a node corresponds to an intersection, a list of link numbers for links connected to a node, a list of adjacent node numbers for nodes adjacent to a node via links, and data related to the height (altitude) of each node point.

[0022] Furthermore, the branching point data 35 stores information such as the name of the intersection at the branching point, the node information that identifies the node forming the branching point, the connection link information that identifies the link connected to the branching point, the name of the direction corresponding to the link connected to the branching point, and information that identifies the shape of the branching point. In this embodiment, branching points include "points where one road branches off to become multiple parallel roads (hereinafter referred to as branching points)" and "points where multiple parallel roads merge to become one road (hereinafter referred to as merging points)" that exist at interchanges and junctions. In addition, it includes merging points and branching points that exist not only on expressways but also on main roads such as national highways. Furthermore, for the above-mentioned merging points and branching points, the position coordinates of the branching / merging point P are also included. Here, the branching / merging point P indicates the boundary point where parallel roads physically separate.

[0023] To explain the branching and merging point P, for example, take the branching point shown in Figure 2, where a side road 46 branches off from the main road 45. At the branching point shown in Figure 2, a new side road 46 appears on the right side (or left side) of the main road, and the main road 45 and side road 46 run parallel to each other in the same direction of travel. A dashed line 47 is drawn between the main road 45 and the side road 46, allowing vehicles to pass each other. Subsequently, the dashed line 47 changes to a zebra stripe 48 between the main road 45 and the side road 46, but vehicles can still pass each other in the section where the zebra stripe 48 is drawn. After that, a median strip 49 appears between the main road 45 and the side road 46, and the appearance of the median strip 49 prevents vehicles from passing each other. The first point where the median strip 49 appears is the boundary point where the parallel roads physically separate, and this is the branching and merging point P. Furthermore, the branching point P also corresponds to the end of the parallel section where vehicles can travel back and forth.

[0024] On the other hand, regarding the branching and merging point P, let us take as an example the merging point shown in Figure 3 where a side road 46 merges with a main road 45. At the merging point shown in Figure 3, the side road 46 approaches the left side (or right side) of the main road, and the main road 45 and side road 46 run parallel to each other in the same direction of travel. Initially, there is a median strip 49 between the main road 45 and the side road 46, and vehicles cannot pass each other. Subsequently, the median strip 49 between the main road 45 and the side road 46 changes to a zebra stripe 48, and vehicles can pass each other. After that, the zebra stripe 48 between the main road 45 and the side road 46 changes to a dashed line marking 47, but even in the section where the dashed line marking 47 is drawn, vehicles can still pass each other. After that, the side road 46 disappears. The last point where the median strip 49 exists is the boundary point where the parallel roads physically separate, and this becomes the junction point P. Furthermore, the junction point P also corresponds to the starting point of the parallel section where vehicles can travel back and forth between the two roads.

[0025] On the other hand, the road image data 36 stores road images showing the road shapes of roads that vehicles can travel on throughout the country. The road images exclude images of facilities that were displayed in conventional map images, and basically consist only of images of the road portion. However, compared to conventional map images, the images specify more detailed information about the road, such as the number of lanes, the type of lane markings, and the specific road shape. In the navigation device 1 of this embodiment, when the vehicle is in motion, it is possible to display the above road images of the area around the vehicle's current location on the liquid crystal display 15 instead of conventional map images.

[0026] Furthermore, the generated map information DB32 stores information about more detailed map information generated by the map information generation processing program (see Figure 4) described later. In particular, in this embodiment, focusing on the areas around the branching point (Figure 2) and merging point (Figure 3) mentioned above, lane information (for example, a coordinate sequence along the lane) is generated for each lane included in the road, specifying its position and shape, and stored in the generated map information DB32. In addition, the road image data 36 mentioned above, especially the road image data 36 around the branching point and merging point, is generated based on the above lane information and is also stored in the generated map information DB32.

[0027] On the other hand, the navigation ECU (Electronic Control Unit) 13 is an electronic control unit that controls the entire navigation device 1, and includes a CPU 41 as an arithmetic unit and control device, a RAM 42 which is used as working memory when the CPU 41 performs various arithmetic processing and stores route data when a route is searched, a ROM 43 which stores control programs as well as map information generation processing programs (see Figure 4) described later, and a flash memory 44 which stores programs read from the ROM 43, and other internal storage devices. The navigation ECU 13 also constitutes various means as processing algorithms. For example, the location information acquisition means acquires location information that identifies the location of the point where a parallel section of roads begins or ends, targeting branching points where one road branches off and becomes multiple parallel roads, or merging points where multiple parallel roads merge to become one road. The information generation means generates lane information that identifies the position and shape of each lane for each lane included in the road at the branching point or merging point, based on road link information for route guidance which includes information on the number of lanes and the above location information. In other words, the navigation ECU 13 is an example of a means for acquiring location information and a means for generating information.

[0028] The operation unit 14 is operated when inputting the starting point (departure point) and the ending point (destination point), and has multiple operation switches (not shown), such as various keys and buttons. The navigation ECU 13 controls the system to perform various operations based on the switch signals output when each switch is pressed. The operation unit 14 may also have a touch panel located in front of the liquid crystal display 15. It may also have a microphone and a voice recognition device.

[0029] Furthermore, the liquid crystal display 15 is a type of display device that shows map images including roads, traffic information, operation guidance, operation menus, key guidance, guidance information along the guided route (planned driving route), news, weather forecasts, time, emails, TV programs, etc. In particular, in this embodiment, when the vehicle is in motion (regardless of whether it is in autonomous or manual driving mode), a road image showing the road shape around the vehicle's current location is displayed on the liquid crystal display 15. Note that a HUD or HMD may be used instead of the liquid crystal display 15.

[0030] Furthermore, the speaker 16 outputs voice guidance that directs the driver along the guided route (planned driving route) based on instructions from the navigation ECU 13, as well as traffic information.

[0031] Furthermore, the DVD drive 17 is a drive capable of reading data recorded on recording media such as DVDs and CDs. Based on the read data, it performs functions such as playing music and videos and updating the map information DB31. Alternatively, a card slot for reading and writing memory cards may be provided instead of the DVD drive 17.

[0032] Furthermore, the communication module 18 is a communication device for receiving traffic information, probe information, weather information, etc. transmitted from a traffic information center, such as a VICS center or probe center, and examples include a mobile phone or a DCM. It also includes vehicle-to-vehicle communication devices for communication between vehicles and vehicle-to-infrastructure communication devices for communication with roadside units.

[0033] Furthermore, the external camera 19 is composed of a camera using a solid-state image sensor such as a CCD, and is mounted on the back of the vehicle's rearview mirror or on the front bumper, with its optical axis oriented at a predetermined angle downward from the horizontal. In addition to detecting obstacles that are subject to warning, when driving with automated driving assistance, the external camera 19 can detect lane markings and other vehicles in the vicinity by performing image processing on the captured image, and control the vehicle's automated driving based on the detection results. It is also possible to identify the lane the vehicle is traveling in based on the detection results of lane markings and road edges by the external camera 19. Furthermore, when driving at the aforementioned branching point (Figure 2) and merging point (Figure 3), it is also possible to detect the median strip 49 and zebra stripe 48, and the external camera 19 can also detect the position coordinates of the aforementioned branching / merging point P. Note that the external camera 19 may be configured to be positioned at the rear or side of the vehicle, in addition to the front.

[0034] Furthermore, the ultrasonic sensor 20 is positioned at predetermined intervals on the front, rear, and sides of the vehicle, for example, and transmits ultrasonic waves as probe waves to the area around the vehicle. It also detects objects that reflected the probe waves by receiving reflected waves that were reflected by objects around the vehicle. Specifically, it is a type of distance measuring sensor that can detect the distance (measured distance value) to the object that reflected the probe waves by measuring the time from transmission to reception. Examples of objects that can be detected by the ultrasonic sensor 20 include people, bicycles, other vehicles, walls and other obstacles that the vehicle must avoid when driving, or obstacles that form a parking space. Note that a millimeter-wave sensor or a laser sensor may be used as the distance measuring sensor instead of an ultrasonic sensor.

[0035] Furthermore, the vehicle control ECU 21 is an electronic control unit that controls the vehicle equipped with the navigation device 1. The vehicle control ECU 21 is also connected to various drive units of the vehicle, such as the steering, brakes, and accelerator, and in this embodiment, it controls each drive unit to provide automatic driving assistance to the vehicle, especially after automatic driving assistance has been initiated in the vehicle.

[0036] Next, the map information generation processing program executed by the CPU 41 in the navigation device 1 according to the above embodiment will be described with reference to Figure 4. Figure 4 is a flowchart of the map information generation processing program according to the above embodiment. Here, the map information generation processing program is executed after the vehicle's ACC power supply (accessory power supply) is turned ON, and is a program that generates more detailed map information in particular with respect to branching points (Figure 2) and merging points (Figure 3). Furthermore, the program shown in the flowchart in Figure 4 below is stored in the RAM 42 and ROM 43 of the navigation device 1 and executed by the CPU 41.

[0037] First, in step 1 (hereinafter abbreviated as S) of the map information generation processing program, the CPU 41 determines the vehicle's current position based on the detection results of the current position detection unit 11 and map information. Furthermore, when determining the vehicle's current position, a map matching process is also performed to match the vehicle's current position with the map information.

[0038] Next, in S2, the CPU 41 obtains map information from the map information DB 31 for a predetermined distance (e.g., 1 km) along the direction of travel from the vehicle's current position. As mentioned above, the map information DB 31 stores simplified map information, including road link information used in the route search process and route guidance to the destination in the navigation device 1, and in S2, this simplified map information is obtained.

[0039] In step S2, if the navigation device 1 has a planned route for the vehicle (for example, a route to the destination), map information is acquired along the planned route for a predetermined distance. On the other hand, if the navigation device 1 does not have a planned route for the vehicle, map information is acquired along the road for a predetermined distance, for example.

[0040] Next, in S3, the CPU 41 determines whether there is a branching point or a merging point ahead in the direction of travel of the vehicle, based on the map information acquired in S2. A branching point is defined as "a point where one road branches off and becomes multiple parallel roads," as shown in Figure 2, and a merging point is defined as "a point where multiple parallel roads merge to become one road," as shown in Figure 3. The information acquired in S2 is simplified map information, but even in simplified map information, a link corresponding to each road is set as link data 33, and connections are made between links at points where roads connect, and information on the number of lanes for each link is also included, so it is possible to identify the existence of the branching points and merging points.

[0041] If it is determined that there is a branching or merging point ahead in the direction of travel of the vehicle (S3: YES), the process proceeds to S4. On the other hand, if it is determined that there is no branching or merging point ahead in the direction of travel of the vehicle (S3: NO), the process returns to S1.

[0042] In S4, the CPU 41 obtains the position coordinates of the branching or merging point P, which is determined to be located ahead of the vehicle's direction of travel. As explained using Figures 2 and 3, the branching or merging point P is the boundary point where parallel roads physically separate. At branching points, the branching or merging point P is the first point where the median strip 49 appears. On the other hand, at merging points, the branching or merging point P is the last point where the median strip 49 exists. This branching or merging point P is the point where the parallel section begins or ends. More specifically, at branching points, it is the point where the parallel section ends, and at merging points, it is the point where the parallel section begins.

[0043] In S4, the coordinates of the branching and merging point P can be obtained by pre-storing information for each branching and merging point P located throughout the country as part of the map information stored in the map information DB31. In this case, S4 can obtain the corresponding branching and merging point P information. The information for branching and merging point P may be obtained from an external server (such as a probe server).

[0044] On the other hand, the coordinates of the junction / merging point P can be detected by the vehicle itself rather than obtained from map information. For example, image recognition could be performed on the image of the area in front of the vehicle captured by the external camera 19, and the boundary between the median strip 49 and the zebra strip 48 could be detected, and the coordinates of that boundary could be obtained as the coordinates of the junction / merging point P.

[0045] Next, in S5, the CPU 41 identifies the area that constitutes a parallel section (parallel road section) with respect to the branching or merging point that has been determined to be ahead of the vehicle's direction of travel. A parallel section is a section in which two or more roads traveling in the same direction are adjacent to each other and vehicles can travel between them. The parallel section is set based on the map information acquired in S2 and the coordinates of the branching / merging point P acquired in S3.

[0046] The following provides a specific example of the process in S5. For example, the branching point shown in Figure 5 represents a point where a four-lane main road branches off into two two-lane main roads. The main road before the branching point is Link A (4 lanes), one of the main roads after the branching point is Link B (2 lanes), and the other main road is Link C (2 lanes). In the above example, the parallel section is defined as the section starting from the connection point where Link A, Link B, and Link C connect (the point where the road links for route guidance branch off) and ending at the branching and merging point P. The connection points of the links are obtained from the map information acquired in S2 above. On the other hand, the merging point shown in Figure 6 indicates a merging point where a 2-lane service road merges with a 3-lane main road. The main road before the merge is Link D (3 lanes), the merging service road is Link E (2 lanes), and the main road after the merge is Link F (3 lanes). In the above example, the parallel section is specified as the section starting from the branching / merging point P and ending at the connection point where Links A, B, and C connect (the point where the road links for route guidance merge). The connection points of the links are obtained from the map information acquired in S2 above. As described above, at branching points, the section from the connection point of each link to the branching / merging point P is identified as a parallel section, while at merging points, the section from the branching / merging point P to the connection point of each link is identified as a parallel section.

[0047] Next, in S6, the CPU 41 sets the number of lanes in the parallel section set in S5 to the sum of the number of lanes in each of the parallel roads, and places virtual lanes 51 on the map. The virtual lane 51 is a line segment that identifies the position and shape of each lane included in the road at a branching or merging point. In other words, the CPU 41 ultimately identifies that there are lanes along the virtual lane 51 placed on the map, with the virtual lane 51 placed on the map as the center line. A virtual lane 51 is placed for each lane; for example, if there is a four-lane road, four virtual lanes will be placed.

[0048] The following provides a specific example of the process in S6. For example, the branching point shown in Figure 7 is a point where a four-lane main road branches into two two-lane main roads, that is, a branching point where the number of lanes does not change before and after the branching point. The main road before the branching point is Link A (number of lanes), one of the main roads after the branching point is Link B (number of lanes), and the other main road is Link C (number of lanes). To explain an example of placing virtual lanes at this branching point, four virtual lanes 51, the same number as the number of lanes in Link A, are placed for Link A, which is the main road before the branching point, and then four virtual lanes 51, the same number as the combined number of lanes in Link B and Link C, which run parallel to each other, are placed in the subsequent parallel section. In particular, the centers of the four virtual lanes 51 placed in the parallel section (i.e., between the second virtual lane 51 from the right and the third virtual lane 51 from the right) are placed so that they coincide with the road centerline 52, which is the angle bisector between Link B and Link C. Furthermore, after the parallel section ends, two virtual lanes 51, the same number as the lanes of Link B, are provided for Link B, which is one of the main roads after the branching point, and two virtual lanes 51, the same number as the lanes of Link C, are provided for Link C, which is the other main road after the branching point. On the other hand, the branching point shown in Figure 8 is a branching point where a 2-lane service road branches off from a 3-lane main road, that is, a branching point where the number of lanes increases or decreases before and after the branching point. The main road before the branching point is Link G (3 lanes), the main road after the branching point is Link H (3 lanes), and the branched service road is Link I (2 lanes). To explain an example of placing virtual lanes at this branching point, three virtual lanes 51, the same number as the lanes of Link G, are placed for Link G, which is the main road before the branching point, and then five virtual lanes 51, the same number as the combined number of lanes of Link H and Link I, are placed in the subsequent parallel section. In particular, the center of the five virtual lanes 51 placed in the parallel section (i.e., the third virtual lane 51 from the right) is positioned to coincide with the road centerline 52, which is the angle bisector between Link H and Link I. Furthermore, after the parallel section ends, three virtual lanes 51, the same number as the lanes of Link H, are placed for Link H, which is the main road, and two virtual lanes 51, the same number as the lanes of Link I, are placed for Link I, which is the side road. Incidentally, as a result of positioning the center of the five virtual lanes 51 placed in the parallel section (i.e., the third virtual lane 51 from the right) to coincide with the road centerline 52, which is the angle bisector between Link H and Link I, the virtual lanes 51 placed for Link G and Link H, which are the main roads, become distorted (zigzag) to the left and right, as shown in Figure 8.

[0049] Next, in S7, the CPU 41 sets (corrects) the spacing (corresponding to the lane width) D of the virtual lanes 51 arranged in S6, based on the map information acquired in S2. For example, a predetermined lane width may be set depending on the type of road (expressway, general road, narrow street, etc.), or for roads where the road width is known, the lane width may be the road width divided by the number of lanes.

[0050] Next, in S8, the CPU 41 modifies the virtual lanes 51 that were positioned in S6 and S7 based on map information to a more appropriate layout. Basically, the virtual lanes 51 are modified so that they are positioned based on the main roads (main roads take priority).

[0051] The following provides a specific example of the process in S8. For example, as shown in Figure 7, let's explain an example of modifying the virtual lanes 51 positioned at a branching point where a main road branches into two main roads (when all roads before and after the branching are main roads). For the two virtual lanes 51 positioned on link B, which is one of the main road lanes after the branching, the position of the virtual lanes 51 is adjusted so that they are at the same angle as link B until they connect with the virtual lanes 51 positioned on link B in the parallel section. Furthermore, the position of the virtual lanes 51 is adjusted so that the centers of the two virtual lanes 51 positioned on link B (i.e., the space between the two virtual lanes 51) coincide with link B. Similarly, for the two virtual lanes 51 positioned on link C, which is the other main road lane after the branching, the position of the virtual lanes 51 is adjusted so that they are at the same angle as link C until they connect with the virtual lanes 51 positioned on link C in the parallel section. Furthermore, the position of the virtual lanes 51 is adjusted so that the centers of the two virtual lanes 51 positioned on link C (i.e., the space between the two virtual lanes 51) coincide with link C. As a result, the virtual lane 51 is positioned at an angle parallel to link A (the first link) up to a predetermined point within the parallel running section, and beyond that point, the virtual lane 51 is positioned at an angle parallel to links B and C (the second links). On the other hand, as shown in Figure 8, an example of modifying the virtual lanes 51 positioned at a branching point where a side road branches off from the main road (when there is only one main road before and after the branching point) is described. The arrangement of the virtual lanes 51 is adjusted so that the center of the three virtual lanes 51 positioned on link G, which is the main road before the branching point (i.e., the second virtual lane 51 from the right), coincides with link G, and similarly, the center of the three virtual lanes 51 positioned on link H, which is the main road after the branching point (i.e., the second virtual lane 51 from the right), coincides with link H. In other words, the virtual lanes 51 are modified by setting the road centerline 52 parallel to the main road, rather than being the angle bisector between link H and link I. Furthermore, for the two virtual lanes 51 positioned on link I, which is the side road, the arrangement of the virtual lanes 51 is adjusted so that the center of the two virtual lanes 51 positioned on link I (i.e., between the two virtual lanes 51) coincides with link I after passing through the parallel section. As a result, the virtual lanes 51 included in the main road are positioned at an angle parallel to links G and H corresponding to the main road, while the virtual lanes 51 included in the side roads are positioned in parallel sections, with the angle gradually changing from an angle parallel to links G and H corresponding to the main road to an angle parallel to link I corresponding to the side road.

[0052] Subsequently, in S9, the CPU 41 stores information identifying the virtual lane 51 whose arrangement was corrected and finally determined in S9 (for example, a coordinate sequence passing through the center of the virtual lane 51) in the generated map information DB 32 in association with the target branching point or merging point. Information regarding the parallel running section identified in S5 may also be stored together with the virtual lane 51. The virtual lane 51 corresponds to the centerline of the lanes included in the road. Therefore, it is possible to estimate that the lanes are located in an area that has half the lane width on both sides of the virtual lane 51, and it is possible to generate the road image data 36 (see Figure 11) described later based on the virtual lane 51. Furthermore, if the parallel running section can be identified, it is also possible to generate road image data 36 that reveals the parallel running section. In other words, the information identifying the virtual lane 51 generated in S4 to S8 corresponds to lane information that identifies the position and shape of each lane included in the road.

[0053] While Figures 7 and 8 illustrate an example of generating a virtual lane 51 at a branching point, it is possible to generate a virtual lane 51 at a merging point using the same method. Essentially, only the orientation is reversed, and the generated virtual lane 51 will have the same shape under the same conditions.

[0054] For example, the merging point shown in Figure 9 is a merging point where two 2-lane main roads merge to form a 4-lane main road, that is, a merging point where the number of lanes does not change before and after the merge. One of the main roads before the merge is Link J (2 lanes), the other main road is Link K (2 lanes), and the main road after the merge is Link L (4 lanes). To explain an example of arranging the virtual lanes S6 at this merging point, two virtual lanes 51, the same number as the number of lanes in Link J, which is the main road before the merge, are arranged for Link J, and similarly, two virtual lanes 51, the same number as the number of lanes in Link K, which is the main road before the merge, are arranged for Link K, and then four virtual lanes 51, the same number as the combined number of lanes in Link J and Link K, which run parallel to each other in the subsequent parallel section, are arranged. In particular, the centers of the four virtual lanes 51 positioned in the parallel section (i.e., between the second virtual lane 51 from the right and the third virtual lane) are positioned to coincide with the road centerline 52, which is the angle bisector between Link J and Link K. Furthermore, after the parallel section ends, four virtual lanes 51, the same number as the lanes of Link L, are positioned for Link L, which is the main road after the merge. Next, to explain an example of modifying the virtual lanes 51 in S8, the two virtual lanes 51 located on link J, which is the main lane before merging, are positioned so that they are at the same angle as link J until they connect with the virtual lanes 51 located on link J in the parallel section. Furthermore, the position of the virtual lanes 51 is adjusted so that the centers of the two virtual lanes 51 located on link J (i.e., the space between the two virtual lanes 51) coincide with link J. Similarly, the two virtual lanes 51 located on link K, which is the other main lane before merging, are positioned so that they are at the same angle as link K until they connect with the virtual lanes 51 located on link K in the parallel section. Furthermore, the position of the virtual lanes 51 is adjusted so that the centers of the two virtual lanes 51 located on link K (i.e., the space between the two virtual lanes 51) coincide with link K. As a result, the virtual lane 51 is positioned at an angle parallel to links J and K (the second link) up to a predetermined point within the parallel running section, and beyond that point, the virtual lane 51 is positioned at an angle parallel to link L (the first link).

[0055] On the other hand, the merging point shown in Figure 10 is a merging point where a 2-lane service road merges with a 3-lane main road, that is, a merging point where the number of lanes increases or decreases before and after the merge. The main road before the merge is Link M (3 lanes), the main road after the merge is Link N (3 lanes), and the merging service road is Link O (2 lanes). To explain an example of arranging the virtual lanes of S6 at this merging point, three virtual lanes 51, the same as the number of lanes in Link M, are arranged for Link M, which is the main road before the merge, two virtual lanes 51, the same as the number of lanes in Link O, which is the service road before the merge, are arranged for Link O, and then five virtual lanes 51, the same as the combined number of lanes in Link M and Link O, which run parallel to each other, are arranged in the subsequent parallel section. In particular, the center of the five virtual lanes 51 placed in the parallel section (i.e., the third virtual lane 51 from the right) is positioned to coincide with the road centerline 52, which is the angle bisector between link M and link O. Furthermore, after the end of the parallel section, three virtual lanes 51, the same number as the lanes of link N, are placed on link N, which is the main road. As a result of positioning the center of the five virtual lanes 51 placed in the parallel section (i.e., the third virtual lane 51 from the right) to coincide with the road centerline 52, which is the angle bisector between link M and link O, the virtual lanes 51 placed on the main roads, link M and link N, become distorted (zigzag) from side to side, as shown in Figure 10. Next, to explain an example of modifying the virtual lanes 51 in S8, the arrangement of the virtual lanes 51 is adjusted so that the center of the three virtual lanes 51 located on link M, which is the main road before merging (i.e., the second virtual lane 51 from the right), coincides with link M, and similarly, the center of the three virtual lanes 51 located on link N, which is the main road after merging (i.e., the second virtual lane 51 from the right), coincides with link N. In other words, the virtual lanes 51 are modified by setting the road centerline 52 parallel to the main road, rather than being the angle bisector between link M and link O. Furthermore, for the two virtual lanes 51 located on link O, which is a side road, the arrangement of the virtual lanes 51 is adjusted so that the center of the two virtual lanes 51 located on link O (i.e., the space between the two virtual lanes 51) coincides with link O before entering the parallel section. As a result, the virtual lanes 51 included in the main road are positioned at an angle parallel to links M and N corresponding to the main road, while the virtual lanes 51 included in the side roads are positioned in parallel sections, with the angle gradually changing from an angle parallel to link O corresponding to the side road to an angle parallel to links M and N corresponding to the main road.

[0056] Next, in S10, the CPU 41 provides vehicle driving assistance using the information of the virtual lane 51 stored in the map information DB 32 generated in S9, as needed. However, the map information generation processing program may only generate the virtual lane and terminate without providing vehicle driving assistance. Furthermore, the information identifying the final determined virtual lane 51 may be sent to an external server. This makes it possible to distribute the information identifying the virtual lane 51 generated in one vehicle to multiple other vehicles.

[0057] The following describes an example of the driving assistance performed in S10, specifically the display of road images around the vehicle on the liquid crystal display 15. First, the CPU 41 obtains road image data 36 around the vehicle's current location from the map information DB 31 or the generated map information DB 32. Here, as mentioned above, the road image data 36 is data in which road images showing the road shape are stored, and compared to conventional map images, it is an image that identifies more detailed information about the road, such as the number of lanes, the type of lane markings, and the specific road shape. In particular, the road image data 36 around merging points and branching points is generated using information of virtual lanes 51 stored in the generated map information DB 32.

[0058] The CPU 41 then displays a road image on the liquid crystal display 15 that shows the road shape around the vehicle's current position, based on the acquired road image data 36. Figure 11 shows an example of a road image 61 displayed on the liquid crystal display 15. As shown in Figure 11, the road image 61 is a bird's-eye view of the area around the vehicle, looking down diagonally from above and behind the vehicle. Only roads are displayed in the road image 61; facilities other than roads are generally not displayed. However, some facilities (for example, destinations, homes, toll booths, ETC gates, etc.) may be included in the display. In addition, the road image 61 displays the number of lanes and the type of lane markings in a discernible manner, and reflects detailed road shapes such as the curvature of curves, resulting in an image that shows a road shape closer to reality. In particular, at merging and branching points, it is possible to show accurate information on how lanes are divided or how the number of lane markings increases or decreases based on the virtual lane 51, and the image clearly shows where parallel sections begin and end. Furthermore, a vehicle icon 62 indicating the vehicle's current position is also displayed.

[0059] Furthermore, the vehicle icon 62 is displayed in a way that allows for identification of the lane the vehicle is currently traveling in. The vehicle's lane is identified, for example, by applying image recognition processing to an image captured by the external camera 19. In particular, by using the virtual lane 51 stored in the generated map information DB 32 in S9, it is possible to accurately identify the lane in which the vehicle is located, even at merging and branching points that are difficult to grasp. The road image 61 is basically displayed on the liquid crystal display 15 continuously until the vehicle finishes traveling. If the vehicle's current position changes, the content of the displayed road image 61 is updated accordingly.

[0060] As described in detail above, the navigation device 1 and the computer program executed by the navigation device 1 according to this embodiment acquire branching points P, which are the positions where parallel sections of roads begin or end, targeting branching points where one road branches off to form multiple parallel roads, or merging points where multiple parallel roads merge to form one road (S4). Based on the road link information for route guidance, which includes information on the number of lanes, and the branching points P, virtual lanes 51 are generated as lane information that specifies the position and shape of each lane included in the road at the branching or merging point (S6-S8). As a result, it becomes possible to generate more detailed map information regarding lanes at branching or merging points based on the road link information for route guidance, which includes information on the number of lanes. Furthermore, at branching points, it is set that there is a section of roads running parallel between the point where the road link for route guidance branches off and the branching / merging point P (S5), and at merging points, it is set that there is a section of roads running parallel between the branching / merging point P and the point where the road links for route guidance merge (S5). A virtual lane 51 is then generated based on the set parallel sections (S6-S8). This makes it possible to identify parallel sections where two or more roads running in the same direction are adjacent and vehicles can travel between them, based on the road link information for route guidance. Then, by using the identified parallel sections, it becomes possible to generate more detailed map information regarding the lanes at branching or merging points. Furthermore, in the road link information for route guidance, if the road link corresponding to one road before branching or after merging is designated as the first link, and the road links corresponding to multiple roads before branching or merging are designated as the second link, then at branching points, virtual lanes 51 are generated for each lane included in the road, assuming that lanes exist at an angle parallel to the first link up to a predetermined point within the parallel section, and lanes exist at an angle parallel to the second link thereafter. Similarly, at merging points, virtual lanes 51 are generated for each lane included in the road, assuming that lanes exist at an angle parallel to the second link up to a predetermined point within the parallel section, and lanes exist at an angle parallel to the first link thereafter. This makes it possible to generate more detailed map information regarding lanes, especially at branching points where the number of lanes does not change before and after branching, for example, at branching points where main roads split into multiple roads. Likewise, at merging points where the number of lanes does not change before and after merging, for example, at merging points where multiple main roads merge into one, it becomes possible to generate more detailed map information regarding lanes. Furthermore, branching points are points where a service road branches off from the main road, and merging points are points where a service road merges with the main road. The road link information for route guidance includes information that identifies the main road and the service road for each road link. For lanes included in the main road, lane information is generated that is at an angle parallel to the road link corresponding to the main road. For lanes included in the service road, lane information is generated in which the angle is gradually changed from an angle parallel to the link corresponding to the main road to an angle parallel to the road link corresponding to the service road in the parallel section. This makes it possible to generate more detailed map information regarding lanes, especially at branching points where the number of lanes increases or decreases before and after the branching point, for example, at branching points where a service road branches off from the main road. Similarly, it makes it possible to generate more detailed map information regarding lanes at merging points where the number of lanes increases or decreases before and after the merge, for example, at merging points where a service road merges with the main road.

[0061] It should be noted that the present invention is not limited to the embodiments described above, and various improvements and modifications are possible without departing from the spirit of the invention. For example, in addition to the branching and merging points shown in Figures 7 to 10, it is also possible to generate a virtual lane 51 at the branching point shown in Figure 12. Here, the branching point shown in Figure 12 indicates a point where a 2-lane service road branches off from a 3-lane main road, while the number of lanes on the main road decreases as a result of the branching. The main road before branching is Link a (3 lanes), the main road after branching is Link b (2 lanes), and the branched service road is Link c (2 lanes). To explain an example of arranging the virtual lanes of S6 at this branching point, three virtual lanes 51, the same number as the number of lanes in Link a, are arranged for Link a, which is the main road before branching, and then four virtual lanes 51, the same number as the combined number of lanes in Link b and Link c, which run parallel to each other in the subsequent parallel section. In particular, the centers of the four virtual lanes 51 arranged in the parallel section (i.e., between the second virtual lane 51 and the third virtual lane 51 from the right) are arranged to coincide with the road centerline 52, which is the angle bisector between Link b and Link c. Furthermore, after the parallel section ends, two virtual lanes 51, the same number as the lanes of link b, are provided for link b, which is the main road, and two virtual lanes 51, the same number as the lanes of link c, are provided for link c, which is the side road. Next, to explain an example of modifying the virtual lanes 51 in S8, the center of the three virtual lanes 51 located on link a, which is the main road before the branching point (i.e., the second virtual lane 51 from the right), coincides with link a. On the other hand, for the two virtual lanes 51 located on link b, which is the main road after the branching point, it is assumed that there are three lanes until the point where they connect with the virtual lane 51 on link c. Similarly, the arrangement of the virtual lanes 51 is adjusted so that the center of the three virtual lanes 51 (i.e., the second virtual lane 51 from the right) coincides with link b. In other words, the virtual lanes 51 are modified by setting the road centerline 52 parallel to the main road, rather than being the angle bisector between link b and link c. Furthermore, for the two virtual lanes 51 located on link c, which is a side road, the arrangement of the virtual lanes 51 is adjusted so that they are at the same angle as link c until they connect with the virtual lane 51 located on link b in the parallel section. In addition, the arrangement of the virtual lanes 51 is adjusted so that the center of the two virtual lanes 51 located on link c (i.e., the point between the two virtual lanes 51) coincides with link c. As a result, the virtual lane 51 included in the main road is positioned at an angle parallel to links a and b corresponding to the main road, while the virtual lane 51 included in the side road is positioned at an angle parallel to links a and b up to a predetermined point within the parallel section, and thereafter at an angle parallel to link c.

[0062] Furthermore, in this embodiment, an example is shown in which a road image 61 (Figure 11) of the area around the vehicle's position is displayed on the liquid crystal display 15 as part of the driving assistance using the virtual lane 51 generated in S6 to S8. However, other types of driving assistance are also possible besides the display of the road image. For example, the information of the virtual lane 51 may be used to identify the vehicle's position through map matching. In particular, by using the virtual lane 51 stored in the generated map information DB 32 in S9, it becomes possible to accurately identify the lane in which the vehicle is located, even at merging and branching points where it is difficult to determine the lanes. As a result, more detailed guidance for lane changes becomes possible. For example, if a guidance route is set to branch off to a side road at a branching point, and it is determined that the vehicle's position is not on the lane corresponding to the side road in the parallel driving section, it is possible to instruct the vehicle to move to the lane corresponding to the side road. In addition, the information of the virtual lane 51 can also be used as information for assisting the vehicle's automatic driving.

[0063] Furthermore, in this embodiment, the map information generation processing program (Figure 4) is executed while the vehicle is in motion. However, if the merging and branching points P can be obtained from a database or an external server, the program can be executed not only while the vehicle is in motion but also while it is stopped. Moreover, in that case, it is possible to generate virtual lanes 51 not only for merging and branching points located ahead of the vehicle's direction of travel, but for merging and branching points throughout the country. Furthermore, if map information and merging and branching points P can be obtained, the execution is not limited to the navigation device 1. For example, a server device can also execute the program.

[0064] Furthermore, in this embodiment, virtual lanes 51 are generated targeting both the merging point and the branching point, but virtual lanes 51 may be generated targeting only one of the merging point or the branching point.

[0065] Furthermore, in this embodiment, the navigation device 1 executes the map information generation processing program (Figure 4), but it may also be configured to be executed by an in-vehicle device other than the navigation device 1 or a vehicle control ECU 21. In that case, the in-vehicle device or vehicle control ECU 21 is configured to acquire the vehicle's current position, map information, etc., from the navigation device 1. Moreover, an external server device may execute some or all of the steps of the map information generation processing program (Figure 4). In that case, the server device corresponds to the map information generation device of this application.

[0066] Furthermore, the present invention can be applied not only to navigation devices but also to mobile phones, smartphones, tablet terminals, personal computers, etc. (hereinafter referred to as "mobile terminals, etc."). It can also be applied to systems consisting of a server and mobile terminals, etc. In that case, each step of the map information generation processing program described above (Figure 4) may be performed by either the server or the mobile terminals, etc. [Explanation of Symbols]

[0067] 1…Navigation device (map information generation device), 13…Navigation ECU (location information acquisition means, example of information generation means), 19…External camera, 31…Map information DB, 33…Link data (road link information), 41…CPU, 51…Virtual lane (lane information), 52…Road centerline, 61…Road image, P…Jumping / merging point (location information)

Claims

1. A location information acquisition means for acquiring location information that identifies the location of the point where a parallel section of roads begins or ends, targeting a branching point where one road branches off and becomes multiple parallel roads, or a confluence point where multiple parallel roads merge to become one road, A map information generating device having information generating means that generates lane information specifying the position and shape of each lane for each lane included in the road at the branching point or merging point, based on road link information for route guidance including information on the number of lanes and the position information.

2. The information generation means is At the aforementioned branching point, it is assumed that a parallel road section exists between the point where the road link for route guidance branches off and the point where the parallel section ends. At the aforementioned merging point, it is assumed that a parallel road section exists between the point where the parallel section begins and the point where the road link for route guidance merges. A map information generation device according to claim 1, which generates lane information based on the set parallel running section.

3. The information generation means is In the aforementioned road link information for route guidance, if the road link corresponding to one road before branching or after merging is designated as the first link, and the road links corresponding to multiple roads before branching or before merging are designated as the second link, At the aforementioned branching point, lane information is generated for each lane included in the road, assuming that lanes exist at an angle parallel to the first link up to a predetermined point within the parallel section, and lanes exist at an angle parallel to the second link beyond that predetermined point. The map information generation device according to claim 2, wherein at the merging point, the lane exists at an angle parallel to the second link up to a predetermined point within the parallel section, and thereafter the lane exists at an angle parallel to the first link, and the lane is generated for each lane included in the road.

4. The aforementioned branching point is a branching point where a side road branches off from the main road, and the aforementioned merging point is a merging point where a side road merges with the main road. The information generation means is The aforementioned road link information for route guidance includes information that identifies the main road and the side road for each road link. For lanes included in the main road, lane information is generated that is at an angle parallel to the road link corresponding to the main road. The map information generation device according to claim 2, which generates lane information for lanes included in the side road, in which the angle is gradually changed from an angle parallel to the road link corresponding to the main road to an angle parallel to the road link corresponding to the side road in the parallel section.

Images