Navigation device and method for navigation

Abstract

To provide a navigation device and a method for navigation capable of eliminating a problem in guiding a branching point having mutually similar indications.SOLUTION: A navigation device (101) includes: a route guidance unit (32) for guiding a route to a set destination by voice; a similarity determination unit (35) for determining, on the basis of the voice for the route guidance, whether there is a similar intersection having an indication similar to that of a target intersection to be guided on the route, in a surrounding area of the target intersection; and a display control unit (134) for, when it is determined that the similar intersection exists, changing a display mode of different characters between indications of the target intersection and the similar intersection in synchronization with the voice guidance of the target intersection, and displaying the changed indications on a windshield.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] BACKGROUND ART Conventionally, a technique is known in which direction information for the next target intersection to be guided is read out based on the travel route and the current position, and voice output guidance is provided (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 09-61187 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the prior art, when a target intersection for which voice guidance is provided is surrounded by a similar intersection with a similar notation to the target intersection, it is possible that the voice guidance may be misunderstood as guidance for a similar intersection. For this reason, there is room for improvement in guidance for intersections with similar notations.

[0005] The present invention has been made in view of the above, and has as its object to provide a navigation device and a navigation method that can eliminate problems in guiding between intersections that are similarly labeled. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the navigation device of the present invention comprises a route guidance unit that provides voice guidance on the route to a set destination, a similarity determination unit that determines whether there is a similar branch point that is included in the voice guidance of the route and that is the subject of guidance on the route and that has a similar notation to the target branch point around the target branch point, and a display control unit that, if it is determined that there is a similar branch point, changes the display mode of the notation of the target branch point and the similar branch point in accordance with the voice guidance of the target branch point and displays them on the display unit.

[0007] In addition, the navigation method of the present invention has a computer execute the following steps: providing voice guidance along a route to a set destination; determining whether there is a similar branch point with a similar notation to the target branch point that is included in the voice guidance of the route and is the subject of guidance on the route, around the target branch point; and, if it is determined that there is a similar branch point, changing the display mode of the notation of the target branch point and the similar branch point in accordance with the voice guidance of the target branch point and displaying them on a display unit. [Effects of the Invention]

[0008] According to the present invention, when a similar junction with a similar notation to the target junction that is included in the route guidance voice and is located around the target junction on the route, the display mode of the notation of the target junction and the similar junction is changed to match the voice guidance of this place name and displayed on the display unit, thereby eliminating problems in guiding mutually similar junctions. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing an example of the configuration of a navigation device according to the first embodiment. [Figure 2] FIG. 2 is a flowchart illustrating an example of processing in the navigation device according to the first embodiment. [Figure 3] FIG. 3 is a schematic diagram showing an example of a state in which kanji characters for difficult-to-read place names are displayed on the windshield with furigana added. [Figure 4] FIG. 4 is a block diagram showing an example of the configuration of a navigation device according to the second embodiment. [Figure 5] FIG. 5 is a flowchart showing an example of processing in the navigation device according to the second embodiment. [Figure 6] FIG. 6 is a schematic diagram showing an example of a state in which different characters in the notation of the target intersection and the similar intersection are displayed on the windshield in different display modes. DETAILED DESCRIPTION OF THE INVENTION

[0010] Below, an embodiment of a navigation device according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to the description of the following embodiment. Furthermore, the components in the following embodiment include those that are replaceable and easy for a person skilled in the art, or those that are substantially identical. Furthermore, the components in the embodiments described below can be variously omitted, replaced, or modified without departing from the spirit of the present invention. In the following embodiment, components necessary for illustrating an embodiment of a navigation device according to the present invention will be described, and other components will be omitted.

[0011] The navigation device according to this embodiment searches for the optimal route between the current location and a destination set by the driver, and provides route guidance to the destination by voice output and map display. The navigation device is a vehicle navigation device that is mounted on a vehicle or is portable and brought into the vehicle. The navigation device may be configured as a portable terminal, a device installed in the vehicle, or a combination of several devices.

[0012] [First embodiment] First, an example of the configuration of a navigation device according to the first embodiment will be described. Fig. 1 is a block diagram showing an example of the configuration of a navigation device according to the first embodiment. The navigation device 1 includes an operation unit 11, a GPS (Global Positioning System) receiving unit 12, a storage unit 13, a speaker 14, a communication unit 15, a display unit 16, and a control device 20. The storage unit 13 also includes a map information storage unit 13A, a guidance history information storage unit 13B, a driving history information storage unit 13C, and a difficult-to-read place name information storage unit 13D. The storage unit 13 may be a storage device such as an external server.

[0013] The operation unit 11 can accept various operations for the control device 20. The operation unit 11 is configured, for example, by a physical operation means for the control device 20, a touch panel arranged on the display unit 16, or an audio input means for collecting sound through a microphone. The operation unit 11 can accept, for example, an operation to input information about a destination or to instruct a route search to the destination. The operation unit 11 can accept, for example, an operation to switch the display information of a route guidance map displayed on the display unit 16. The operation unit 11 outputs the operation information to the operation acceptance control unit 21 of the control device 20.

[0014] The GPS receiver 12 receives radio waves from a GPS satellite (not shown) and outputs the received radio wave signal to the position information acquisition unit 22 of the control device 20.

[0015] The map information storage unit 13A stores map information. The map information is road information. The map information also includes information on place names of areas where roads extend and place names of intersections (branch points) located on the roads. The map information storage unit 13A outputs the stored map information to the map information acquisition unit 23 of the control device 20.

[0016] The guidance history information storage unit 13B stores guidance history information of place names included in the route guidance voice. For example, when route guidance is given by voice such as "Turn left at the intersection of XX town about 300 meters ahead," the guidance history information storage unit 13B stores the place name information of "XX town" as guidance history information. Also, when route guidance is given by voice such as "Turn left at the intersection of XX town about 300 meters ahead and head towards △△," the guidance history information storage unit 13B stores the place name information of "XX town" and "△△" as guidance history information. The guidance history information storage unit 13B outputs the stored guidance history information to the guidance history information acquisition unit 24 of the control device 20.

[0017] The driving history information storage unit 13C stores driving history information of the vehicle, i.e., history information of changes in vehicle position information while the vehicle is traveling. The driving history information storage unit 13C outputs the stored driving history information to the driving history information acquisition unit 25 of the control device 20.

[0018] The difficult-to-read place name information storage unit 13D stores an information list of difficult-to-read place names that lists predetermined difficult-to-read place name information. Difficult-to-read place names are place names written in difficult-to-read kanji, such as Tomigusuku City, Nogata City, Kushibiruhanari, Gusukushima, Yabuguro, and Hirakata. Difficult-to-read place names also include place names that contain non-standard kanji (non-standard characters), such as Kamisu City and Azahotokesawa, as well as place names with pronunciations derived from local languages ​​(e.g., the Ainu language of Hokkaido), such as Tonge Town, Chippubetsu, and Topushi. Furthermore, difficult-to-read place names include place names that are written with the same kanji but are pronounced differently depending on the region, such as Kobe City, Hyogo Prefecture, Kobe Town, Anpachi District, Gifu Prefecture, and Kobe, Hinohara Village, Nishitama District, Tokyo.The difficult-to-read place names listed above are merely examples and are not limited to these.The difficult-to-read place name information storage unit 13D outputs a list of stored difficult-to-read place name information to the difficult-to-read place name information acquisition unit 26 of the control device 20.

[0019] The speaker 14 is a sound emitting device installed inside the vehicle. The speaker 14 emits guidance audio when the navigation device 1 provides route guidance to the destination. The speaker 14 emits the guidance audio inside the vehicle based on an audio signal output from the route guidance unit 32 of the control device 20.

[0020] The communication unit 15 is a communication unit. The communication unit 15 may perform communication via the Internet, a mobile phone line, or the like. The communication unit 15 performs various communications based on control signals output from the communication control unit 33 of the control device 20.

[0021] The display unit 16 may be, for example, a display device specific to the navigation device 1 or a display device shared with other systems, including car audio. The display unit 16 may be, for example, a display including a liquid crystal display or an organic electroluminescence (EL) display. When the navigation device 1 is installed in a vehicle, the display unit 16 is disposed on a dashboard in front of the driver's seat, an instrument panel, a center console, or the like. The display unit 16 displays route guidance images, such as symbols indicating the current location and destination and lines indicating the guide route, on a map from the current location to the destination, based on a video signal output from the display control unit 34 of the control device 20. In this embodiment, the display unit 16 includes, for example, a head-up display unit (not shown) disposed in the dashboard of the vehicle. This head-up display unit displays an image on the windshield by projecting a portion of the image onto the windshield. In this embodiment, for example, if a place name included in the route guidance audio is difficult to read, an image with furigana added to the kanji characters representing the place name is displayed on the windshield.

[0022] The control device 20 includes a storage device that stores various control programs and data used in various control processes, and an arithmetic processing device that executes predetermined control programs. The storage device is, for example, a non-volatile or volatile semiconductor memory such as a read-only memory (ROM), a random access memory (RAM), a hard disk drive (HDD), or a flash memory. The arithmetic processing device is, for example, a central processing unit (CPU), a microprocessor, or a microcomputer. The control device 20 is implemented by one or more storage devices and one or more arithmetic processing devices.

[0023] The control device 20 has an operation reception control unit 21, a location information acquisition unit 22, a map information acquisition unit 23, a guidance history information acquisition unit 24, a driving history information acquisition unit 25, a difficult-to-read place name information acquisition unit 26, a difficult-to-read place name determination unit 30, a route search unit 31, a route guidance unit 32, a communication control unit 33, and a display control unit 34. Each of these is connected by a bus BS.

[0024] The operation reception control unit 21 acquires operation information input to the operation unit 11. The operation reception control unit 21 receives various types of operation information, such as an operation to input destination information or a route search to the destination, and outputs a control signal.

[0025] The location information acquisition unit 22 acquires location information indicating the current location of the vehicle. In this embodiment, the location information acquisition unit 22 acquires the location information of the vehicle based on radio wave signals acquired by the GPS receiving unit 12. The location information acquisition unit 22 outputs the acquired location information of the vehicle to the driving history information storage unit 13C, the map information acquisition unit 23, the guidance history information acquisition unit 24, the driving history information acquisition unit 25, the difficult-to-read place name determination unit 30, the route search unit 31, the route guidance unit 32, and the display control unit 34.

[0026] The map information acquisition unit 23 acquires map information from the map information storage unit 13A. The map information acquisition unit 23 acquires map information relating to the area from the current location of the vehicle to the destination, based on the location information of the vehicle acquired by the location information acquisition unit 22 and the location information of the destination acquired by the operation reception control unit 21. The map information acquisition unit 23 outputs the acquired map information to the display control unit 34.

[0027] The guidance history information acquisition unit 24 acquires guidance history information from the guidance history information storage unit 13B. The guidance history information acquisition unit 24 acquires guidance history information relating to the area from the current location of the vehicle to arrival at the destination, based on the location information of the vehicle acquired by the location information acquisition unit 22 and the location information of the destination acquired by the operation reception control unit 21. The guidance history information acquisition unit 24 outputs the acquired guidance history information to the difficult-to-read place name determination unit 30.

[0028] The driving history information acquisition unit 25 acquires driving history information from the driving history information storage unit 13C. The driving history information acquisition unit 25 acquires driving history information relating to the area from the current location of the vehicle to the arrival at the destination, based on the location information of the vehicle acquired by the location information acquisition unit 22 and the location information of the destination acquired by the operation reception control unit 21. The driving history information acquisition unit 25 outputs the acquired driving history information to the difficult-to-read place name determination unit 30.

[0029] The difficult-to-read place name information acquisition unit 26 acquires difficult-to-read place name information from the difficult-to-read place name information storage unit 13D. The difficult-to-read place name information acquisition unit 26 acquires difficult-to-read place name information relating to the area from the current location of the vehicle to the arrival at the destination, based on the location information of the vehicle acquired by the location information acquisition unit 22 and the location information of the destination acquired by the operation reception control unit 21. The difficult-to-read place name information acquisition unit 26 outputs the acquired difficult-to-read place name information to the difficult-to-read place name determination unit 30.

[0030] Based on the acquired difficult-to-read place name information and guidance history information, the difficult-to-read place name determination unit 30 determines whether a place name included in the route guidance audio is a difficult-to-read place name written in difficult-to-read kanji. Specifically, if a place name included in the route guidance audio is included in the difficult-to-read place name information list and has not been given voice guidance for that place name (is not included in the guidance history information) within a predetermined period of time from the present to the past (e.g., one week), the difficult-to-read place name determination unit 30 determines that the place name is difficult to read. Note that the difficult-to-read place name determination unit 30 may use driving history information instead of guidance history information, and determine that the place name is difficult to read if the place name included in the route guidance audio is included in the difficult-to-read place name information list and has not had driving history at location information corresponding to that place name within a predetermined period of time from the present to the past (e.g., one week). The difficult-to-read place name determination unit 30 outputs the determination result to the display control unit 34.

[0031] The route search unit 31 searches for a route from the current position of the vehicle to the destination. Furthermore, if a traffic jam occurs while guiding the searched route, the route search unit 31 may search for a new route at the driver's instruction. The route search unit 31 presents the searched route to the driver. The method of searching for a route is not limited and any known route search method can be used.

[0032] The route guidance unit 32 provides route guidance from the current position of the vehicle to the destination. More specifically, the route guidance unit 32 provides route guidance along the searched route. The route guidance unit 32 provides route guidance from the current position of the vehicle to the destination by voice.

[0033] The communication control unit 33 controls communication in the communication unit 15. The communication control unit 33 performs wireless communication with an external information server (not shown) via the communication unit 15. In this embodiment, the communication control unit 33 may search for and receive information about roads included in the route to the destination and the surrounding environment of the roads from the external information server.

[0034] The display control unit 34 displays the route searched by the route search unit 31 on the display unit 16. For example, the display control unit 34 displays the searched route by superimposing it on a map image. Furthermore, when it is determined that the place name is difficult to read, the display control unit 34 displays the kanji representing the place name with furigana in sync with the voice guidance of the place name on the windshield (a predetermined area included within the field of vision of the driver while driving).

[0035] Next, an example of the processing of the navigation device will be described. Fig. 2 is a flowchart showing an example of the processing in the navigation device according to the first embodiment. Fig. 3 is a schematic diagram showing an example of a state in which furigana characters are added to difficult-to-read place names and the name is displayed on the windshield. The processing shown in Fig. 2 is executed by the control device 20 based on predetermined control programs and data.

[0036] When a route search operation to a destination is performed via the operation unit 11 (step S11), the control device 20 provides route guidance by voice according to the searched route (step S12). More specifically, the control device 20 causes the route search unit 31 to search for and set a route to the destination. Then, the route guidance unit 32 provides voice guidance for the vehicle so that the vehicle moves (travels) along the set route based on the position information of the vehicle acquired by the position information acquisition unit 22.

[0037] Next, the control device 20 acquires guidance history information (step S13) and acquires list information of difficult-to-read place names (step S14). More specifically, the control device 20 acquires, via the guidance history information acquisition unit 24, guidance history information of place names that have been included in voice route guidance in the past, for example, for the area up to the destination, from the guidance history information storage unit 13B. Note that the control device 20 may acquire guidance history information of all place names that are stored in the guidance history information storage unit 13B and have been included in voice route guidance in the past. Furthermore, the control device 20 acquires, via the difficult-to-read place name information acquisition unit 26, information on difficult-to-read place names that exist in the area up to the destination, from the difficult-to-read place name information storage unit 13D. Note that the control device 20 may acquire all difficult-to-read place name information stored in the difficult-to-read place name information storage unit 13D.

[0038] Next, the control device 20 determines whether the place name included in the speech of the upcoming route guidance is a difficult-to-read place name (step S15). More specifically, the control device 20 determines, using the difficult-to-read place name determination unit 30, whether the place name included in the speech of the route guidance is a difficult-to-read place name written in difficult-to-read kanji, based on the acquired difficult-to-read place name information and guidance history information. Specifically, the difficult-to-read place name determination unit 30 determines that the place name included in the speech of the route guidance is a difficult-to-read place name if the following conditions are met: the place name is included in the difficult-to-read place name information list, and voice guidance for the target place name has not been provided within a predetermined period of time (e.g., one week) from the present. On the other hand, if the above-mentioned conditions are not met, the difficult-to-read place name determination unit 30 determines that the place name is not a difficult-to-read place name. In this determination, if the control device 20 determines that the place name is not a difficult-to-read place name (step S15; No), the control device 20 proceeds to step S17.

[0039] Furthermore, if this judgment determines that the place name is difficult to read (step S15; Yes), the control device 20 causes the display control unit 34 to add furigana to the kanji representing the place name and display it on the windshield (display unit 16) (step S16).

[0040] As shown in FIG. 3, a dashboard 100, a steering wheel 105 rotatable relative to the dashboard 100, and a windshield 102 located above the dashboard 100 are provided in front of the driver's seat of the vehicle. The dashboard 100 is a member that separates the interior of the vehicle from the engine compartment. A meter panel (also referred to as an instrument panel) 103 equipped with, for example, a speedometer and a tachometer is provided in front of the dashboard 100, and a display unit 16 equipped with, for example, the above-mentioned touch panel is disposed in front of the space between the driver's seat and the passenger seat. The steering wheel 105 is a member that accepts steering operations for steering the vehicle. The windshield 102 is a member that serves as a windscreen while driving, and is formed of a transparent member such as glass that allows forward visibility.

[0041] Since the windshield 102 is located in the driver's line of sight while driving, the windshield 102 functions as a predetermined area included within the driver's field of vision while driving. For this reason, by displaying an image showing specific information on the windshield 102 using, for example, a head-up display unit (not shown) located in the dashboard 100, the driver can view the image (information) displayed on the windshield 102 without shifting their line of sight as much as possible.

[0042] In this embodiment, when it is determined that the place name is difficult to read (step S15; Yes), the control device 20 causes the display control unit 34 to display auxiliary display 110 on the windshield (display unit 16) in accordance with the audio guidance including the difficult-to-read place name (step S16). Specifically, the control device 20 displays auxiliary display 110 including kanji 111 indicating the difficult-to-read place name (in FIG. 3 , 'Yabuguro'), ruby ​​112 for the kanji 111 (in FIG. 3 , 'Yabuguro'), and an arrow 113 indicating the vehicle's traveling direction (in FIG. 3 , a left-turn arrow), on the windshield 102 in accordance with the audio guidance, for example, "Turn left at the intersection of XX town, approximately 300 meters ahead." In this case, the display control unit 34 may display the arrow 113 simultaneously with the kanji 111 and ruby ​​112, or may display the arrow 113 a predetermined time (for example, one second) after the kanji 111 and ruby ​​112. When the vehicle passes a target point for voice guidance (for example, an intersection), the control device 20 causes the display control unit 34 to stop displaying the auxiliary display 110. In the example of Fig. 3, the auxiliary display 110 is displayed on the lower part of the windshield 102 in front of the driver's seat, but the display area can be changed as appropriate as long as it does not affect the field of vision while driving.

[0043] Next, the control device 20 determines whether the host vehicle has arrived at the destination (step S17). If the host vehicle has not arrived at the destination (step S17; No), the control device 20 returns the process to step S12 and repeats steps S12 to S17. On the other hand, if the host vehicle has arrived at the destination (step S17; Yes), the control device 20 ends the process.

[0044] As described above, the navigation device 1 of this embodiment includes a route guidance unit 32 that provides voice guidance on the route to a set destination, an difficult-to-read place name determination unit 30 that determines whether a place name included in the voice guidance is a difficult-to-read place name written in kanji that is difficult to read, and a display control unit 34 that, if it is determined to be a difficult-to-read place name, displays the kanji representing the place name with furigana added in conjunction with the voice guidance of the place name. This makes it easy to determine whether the kanji representing the place name written on signs, etc. along the driving route match the place name announced in the voice guidance, thereby eliminating problems with guidance of difficult-to-read place names.

[0045] The navigation device 1 of this embodiment is equipped with a difficult-to-read place name information acquisition unit 26 that acquires an information list of difficult-to-read place names, and a guidance history information acquisition unit 24 that acquires history information of place names that have been given voice guidance in the past.The difficult-to-read place name determination unit 30 determines that a place name is difficult to read if it is included in the information list and has not been given voice guidance for the place name within a predetermined period of time from the present to the past, so that it can easily determine whether a place name written on a sign or the like along a driving route is a difficult-to-read place name.

[0046] In the navigation device 1 of this embodiment, place names are those that are guided along the route to the destination, so even if a place name is suddenly announced by voice guidance along the route, it is possible to provide appropriate guidance on a place name that is difficult to read.

[0047] In the navigation device 1 of this embodiment, when a place name is determined to be difficult to read, the display control unit 34 displays an arrow symbol indicating the direction of travel along with the voice guidance of the place name, thereby enabling appropriate route guidance.

[0048] Furthermore, in the navigation device 1 according to this embodiment, kanji characters indicating difficult-to-read place names are displayed on the windshield with furigana added, so the driver can see the information displayed on the windshield 102 without shifting his or her gaze as much as possible.

[0049] [Second embodiment] Next, an example of the configuration of a navigation device according to a second embodiment will be described. When a similar intersection with a similar notation to a target intersection that is included in the voice guidance of the route and that is the subject of guidance on the route is located near the target intersection, the navigation device 101 according to the second embodiment changes the display mode of the different characters in the notation of the target intersection and the similar intersection in accordance with the voice guidance of the target intersection. FIG. 4 is a block diagram showing an example of the configuration of a navigation device according to the second embodiment. The navigation device 101 includes an operation unit 11, a GPS receiving unit 12, a memory unit 130, a speaker 14, a communication unit 15, a display unit 16, and a control device 120. The memory unit 130 also includes a map information memory unit 13A and an intersection information memory unit 13E. Note that the memory unit 130 may be a storage device such as an external server. The same components as those in the first embodiment are designated by the same reference numerals, and description thereof will be omitted.

[0050] The intersection information storage unit (branch information storage unit) 13E stores intersection information (branch information) related to intersections (branch points). An intersection refers to a location where two roads intersect, but in this embodiment, an intersection also includes a branch point where one road branches into two. Specifically, the intersection information storage unit 13E stores, as intersection information, location information of the intersection, information related to the place name (name) of the intersection, information related to the notation of the intersection, etc. The intersection information storage unit 13E outputs the stored intersection information to the intersection information acquisition unit (branch information acquisition unit) 27 of the control device 120.

[0051] In this embodiment as well, the display unit 16 may include, for example, a display device specific to the navigation device 101, a display device shared with other systems including car audio, or a head-up display unit (not shown) disposed in the dashboard of the vehicle. In this embodiment, for example, when a similar intersection with a similar notation to a target intersection included in the audio of route guidance is located around the target intersection, an image in which the different characters in the notation of the target intersection and the similar intersection are displayed in a different manner is displayed on the windshield.

[0052] The control device 120 includes an operation reception control unit 21, a location information acquisition unit 22, a map information acquisition unit 23, an intersection information acquisition unit 27, a similarity determination unit 35, a route search unit 31, a route guidance unit 32, a communication control unit 33, and a display control unit 134. Each of these is connected by a bus BS.

[0053] The intersection information acquisition unit 27 acquires intersection information from the intersection information storage unit 13E. The intersection information acquisition unit 27 acquires intersection information relating to the area from the current location of the vehicle to the destination, based on the position information of the vehicle acquired by the position information acquisition unit 22 and the position information of the destination acquired by the operation reception control unit 21. The intersection information acquisition unit 27 outputs the acquired intersection information to the similarity determination unit 35.

[0054] Based on the acquired intersection information, the similarity determination unit 35 determines whether there is a similar intersection (similar junction) with a similar notation to the target intersection (target junction) that is included in the route guidance voice and is located near the target intersection (target junction) on the route. As described above, this intersection information includes intersection location information, information about the intersection's place name (name), information about the intersection's notation, etc. The similarity determination unit 35 determines that the notation of the target intersection and the similar intersection are similar if any one character in a string of three or more characters is different. For example, if there is an intersection "XX-cho 2-chome" near the target intersection "XX-cho 1-chome" on the route, the notation of the target intersection "XX-cho 1-chome" and the similar intersection "XX-cho 2-chome" are determined to be similar. Furthermore, for example, the notation of "XX Kitamachi" and "XX Nakamachi" are determined to be similar, but the notation of "△△ Station" and "△△ Station North Exit" are determined to be dissimilar because they differ by two or more characters. Furthermore, the vicinity of the target intersection to be guided on the route means that the similar intersection is within a predetermined distance (for example, 200 m) from the target intersection, but it is preferable that the similar intersection and the target intersection are adjacent to each other. The similarity determination unit 35 outputs the determination result to the display control unit 134.

[0055] The display control unit 134 causes the display unit 16 to display the route searched for by the route search unit 31. For example, the display control unit 134 displays the searched route by superimposing it on a map image. Furthermore, when it is determined that there is a similar intersection with a similar notation to the target intersection, the display control unit 134 changes the display mode of the different characters in the notation of the target intersection and the similar intersection, and displays them on the windshield (a predetermined area included in the driver's field of vision while driving) in accordance with the audio guidance for the target intersection. The display control unit 134 displays the different characters by changing at least one of the color and size from the other characters. For example, in the case of "XX Kitamachi" and "XX Nakamachi," the different characters "Kita" and "Naka" are displayed in a different color from the other characters "XXmachi," underlined, or larger than the other characters "XXmachi." In this case, the display control unit 134 has been described as changing the display mode of each of the different characters (e.g., "kita" and "naka"), but it is sufficient to change the display mode of at least one of them. Furthermore, if the different characters are Chinese numerals, the display control unit 134 changes the Chinese numerals to at least one of Arabic numerals and Roman numerals. In the case of "XX-cho 1-chome" and "XX-cho 2-chome," the different Chinese numerals "ichi" and "ni" are changed to Arabic numerals "1" and "2," respectively. In this case, the color and size of the characters may also be changed. This allows the difference between different characters at intersections with similar notations to be emphasized, thereby eliminating misreading or misunderstanding of intersection names. Note that when Chinese numerals are included in places other than the hinge number, for example, place names that begin with a Chinese numeral, such as Nijo Ohashi, Sanjo Ohashi, and Shijo Ohashi, which are place names in Kyoto Prefecture, it is appropriate to distinguish the color and size of the different characters from the other characters without changing them to Arabic numerals.

[0056] Next, an example of the processing of the navigation device will be described. Fig. 5 is a flowchart showing an example of the processing in the navigation device according to the second embodiment. Fig. 6 is a schematic diagram showing an example of a state in which different character display modes for notating the target intersection and similar intersections are changed and displayed on the windshield. The processing shown in Fig. 6 is executed by the control device 120 based on predetermined control programs and data.

[0057] When a route search operation to a destination is performed via the operation unit 11 (step S21), the control device 120 provides route guidance by voice according to the searched route (step S22). More specifically, the control device 120 causes the route search unit 31 to search for and set a route to the destination. Then, the route guidance unit 32 provides voice guidance for the vehicle so that the vehicle moves (travels) along the set route based on the position information of the vehicle acquired by the position information acquisition unit 22.

[0058] Next, the control device 120 acquires intersection information (step S23). More specifically, the control device 120 acquires, for example, intersection information existing in an area up to the destination from the intersection information storage unit 13E using the intersection information acquisition unit 27. Note that the control device 120 may acquire all intersection information stored in the intersection information storage unit 13E.

[0059] Next, the control device 120 determines, using the similarity determination unit 35, whether or not there is a similar intersection on the route around the target intersection to be guided that has a similar notation to the target intersection (step S24). Specifically, the similarity determination unit 35 determines that the notation of the target intersection and the similar intersection are similar if any one character in a string of three or more characters is different. Furthermore, the vicinity of the target intersection to be guided on the route means that the similar intersection is within a predetermined distance (for example, 200 m) from the target intersection. If it is determined in this determination that there is no similar intersection around the target intersection (step S24; No), the control device 120 proceeds to step S26.

[0060] Also, in this determination, when it is determined that there is a similar intersection near the target intersection (step S24; Yes), the control device 120 causes the display control unit 134 to change the display mode of different characters in the notations of this target intersection and the similar intersection and display them on the windshield (display unit 16) (step S25).

[0061] Specifically, as shown in FIG. 6, the control device 120 displays the auxiliary display 210 on the windshield 102 in accordance with, for example, the voice guidance "Turn left at the intersection about 300 m ahead, at the second crossroads of ○○ Street". In the example of FIG. 6, the auxiliary display 210 includes a schematic image 211 schematically showing the target intersection and the similar intersection, a character string 212 showing the target intersection, a character string 213 showing the similar intersection, and an arrow 214 (in FIG. 6, a left-turn arrow) indicating the traveling direction of the vehicle. Here, the display control unit 134 changes and displays, for example, different characters 212A and 213A in the notations of the target intersection "First Crossroads of ○○ Street" and the similar intersection "First Crossroads of ○○ Street" from Chinese numerals "one" and "two" to Arabic numerals "1" and "2", respectively. Further, the display control unit 134 changes and displays the above different characters 212A and 213A (in FIG. 6, "1" and "2") to be larger in character size than other characters "Crossroads of ×× Street". Further, the display control unit 134 may display the arrow 214 simultaneously with the above schematic image 211 and character strings 212 and 213, or may display it with a delay of a predetermined time (for example, 1 second) from the above schematic image 211 and character strings 212 and 213. When the vehicle passes through the target intersection of the voice guidance, the control device 120 stops the display of the auxiliary display 210 by the display control unit 134. In the example of FIG. 6, although the auxiliary display 210 is displayed at the lower part in front of the driver's seat on the windshield 102, the display area can be appropriately changed within a range that does not affect the field of view during driving.

[0062] Next, the control device 120 determines whether the host vehicle has arrived at the destination (step S26). If the host vehicle has not arrived at the destination (step S26; No), the control device 120 returns the process to step S22 and repeats steps S22 to S26. On the other hand, if the host vehicle has arrived at the destination (step S26; Yes), the control device 120 ends the process.

[0063] As described above, the navigation device 101 of this embodiment includes a route guidance unit 32 that provides voice guidance on the route to a set destination, a similarity determination unit 35 that determines whether there are similar intersections with notations similar to those of a target intersection that are included in the voice guidance of the route and that are the subject of guidance on the route, around the target intersection, and a display control unit 134 that, if it is determined that there are similar intersections, changes the display mode of the notations of the target intersection and similar intersections to match the voice guidance of the target intersection. This makes it possible to display intersections with similar notations in different modes, thereby eliminating mistakes and misunderstandings about intersection names and eliminating problems in guiding intersections with mutually similar notations.

[0064] In the navigation device 101 of this embodiment, the similarity determination unit 35 determines that the notation of the target intersection and the similar intersection are similar if any one character in a string of three or more characters is different, so it is easy to determine whether the names of each intersection on the driving route are similar to each other.

[0065] In the navigation device 101 of this embodiment, the display control unit 134 changes the display mode of at least one of the different characters in the notation of the target junction and the similar junction, thereby emphasizing the differences between the different characters at intersections with similar notation, thereby eliminating misreading or misunderstanding of intersection names.

[0066] In the navigation device 101 of this embodiment, the display control unit 134 displays different characters by changing at least one of the color and size of the characters compared to other characters, thereby emphasizing the differences between different characters at intersections with similar notation, thereby eliminating misreading or misunderstanding of intersection names.

[0067] In the navigation device 101 of this embodiment, if the different characters are Chinese numerals, the display control unit 134 changes the Chinese numerals to at least one of Arabic numerals and Roman numerals before displaying them, thereby emphasizing the different characters at intersections with similar notations, thereby eliminating misreading or misunderstanding of intersection names.

[0068] Furthermore, in the navigation device 101 according to this embodiment, the display mode of different characters in the notation of the target intersection and similar intersections is changed and displayed on the windshield 102, so that the driver can see the information displayed on the windshield 102 without shifting his or her line of sight as much as possible.

[0069] In the above-described embodiment, the components of the illustrated control devices 20 and 120 are conceptual and functionally independent, and may not necessarily be physically configured as illustrated. In other words, the specific form of each device is not limited to that shown in the drawings, and all or part of the devices may be functionally or physically distributed or integrated in any unit depending on the processing load, usage status, etc. of each device.

[0070] The configuration of the control devices 20 and 120 is realized, for example, as software, by a program loaded into a memory. In the above embodiments, the configuration has been described as a functional block realized by cooperation of these hardware and software. In other words, these functional blocks can be realized in various forms by hardware alone, software alone, or a combination thereof.

[0071] In the above embodiment, the windshield 102 has been described as an example of a predetermined area included within the driver's field of vision while driving, but the present invention is not limited to this. For example, a so-called electronic instrument panel may be used, in which meters such as a speedometer and a tachometer are displayed on a liquid crystal panel arranged on the dashboard of the vehicle. In this case, the auxiliary displays 110, 210 may be displayed in a location on the electronic instrument panel that does not need to be displayed constantly for driving, such as the speedometer. [Explanation of symbols]

[0072] 1, 101 Navigation device 14 Speaker 16 Display section 20, 120 Control device 24 Guidance history information acquisition unit 26 Difficult to read place name information acquisition unit 27 Intersection information acquisition unit 30 Difficult to read place name determination section 31 Route search section 32 Route guidance section 34, 134 Display control unit 35 Similarity determination section 102 Windshield 110, 210 Auxiliary display 111 Kanji 112 Ruby 113 Arrow 211 Schematic image 212, 213 String (other characters) 212A, 213A different characters

Claims

1. a route guidance unit that provides voice guidance on a route to a set destination; a similarity determination unit that determines whether or not there is a similar branch point with a notation similar to that of a target branch point that is included in the voice of the route guidance and is a guidance target on the route, in the vicinity of the target branch point; a display control unit that, when it is determined that the similar junction exists, changes the display mode of the notation of the target junction and the similar junction in accordance with the voice guidance of the target junction and displays them on a display unit; A navigation device comprising:

2. The navigation device according to claim 1 , wherein the similarity determination unit determines that the target branch point and the similar branch point are similar in notation when any one character in a character string of three or more characters is different.

3. The navigation device according to claim 1 or 2, wherein the display control unit changes a display mode of at least one of the different characters in the representations of the target junction and the similar junction, and displays them.

4. The navigation device according to claim 3 , wherein, when the different characters are Chinese numerals, the display control unit changes the Chinese numerals to at least one of Arabic numerals and Roman numerals before displaying them.

5. providing voice guidance along a route to the set destination; a step of determining whether or not there is a similar junction with a similar notation to a target junction that is included in the voice of the route guidance and is to be guided on the route, in the vicinity of the target junction; when it is determined that there is a similar branch point, changing the display mode of the notation of the target branch point and the similar branch point and displaying them on a display unit in accordance with the voice guidance of the target branch point; A navigation method for causing a computer to execute the above.

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