JP2024052926A - Information processing device, information processing method, information processing program, and recording medium - Google Patents

Abstract

[Problem] A method is provided for determining whether or not there is a time difference between the manner in which a traffic signal changes, as indicated by traffic light information, and the manner in which the traffic signal actually changes as indicated by a traffic light. [Solution] Signal information indicating the manner in which a traffic signal changes as indicated by a traffic light is obtained, imaging information obtained by imaging the traffic light is obtained, and a method is provided for determining whether or not there is a time difference between the manner in which the traffic signal changes as indicated by the obtained signal information and the manner in which the traffic signal changes as indicated by the obtained imaging information is output by the traffic light, as specified based on the obtained imaging information. [Selected Figure] Figure 1

Description

This application relates to the technical field of information processing devices that process information used to assist the driving of mobile objects in relation to traffic signals.

Conventionally, a technology is known in which communication devices such as optical beacons are installed along roads, and traffic light information indicating the expected change in traffic light output from traffic lights, such as the start timing and duration, is transmitted from the communication devices to vehicles traveling nearby. The vehicle that receives this traffic light information provides, for example, information to assist the driver of the vehicle in driving. For example, Patent Document 1 discloses a driver assistance device that acquires the distance from the vehicle to an intersection where traffic lights are located, calculates the range of driving speeds at which the vehicle can enter the intersection when the traffic lights are green based on the acquired distance and traffic light information, and outputs this range of driving speeds.

JP 2011-227761 A

However, for some reason, the actual change in the traffic signal output by the traffic light may be out of sync with the change indicated by the signal information. If such a lag occurs, there is a risk that the vehicle driving cannot be properly supported.

The present application has been made in consideration of the above points, and an example of the objective thereof is to provide an information processing device, an information processing method, an information processing program, and a recording medium that make it possible to determine whether or not there is a time difference between the manner in which a traffic signal changes as indicated by traffic light information and the manner in which a traffic signal actually changes as indicated by a traffic light.

One aspect of the present application is an information processing device that includes a signal information acquisition means for acquiring signal information indicating the manner in which a traffic signal changes, which is output by a traffic light, an imaging information acquisition means for acquiring imaging information obtained by imaging the traffic light, and a determination means for determining whether or not there is a time difference between the manner in which the traffic signal changes, which is indicated by the acquired signal information, and the manner in which the traffic signal changes, which is specified based on the acquired imaging information, is output by the traffic light.

1 is a block diagram showing an example of a schematic configuration of an information processing device according to an embodiment. 1 is a block diagram showing an example of a schematic configuration of a driving assistance system according to an embodiment. 1A is a block diagram showing an example of a schematic configuration of a server device according to an embodiment, and FIG. 1B is a block diagram showing an example of a schematic configuration of a navigation device according to an embodiment; 1A is a diagram showing an example of a traffic light image captured from a vehicle, and FIG. 1B is a diagram showing an example of a difference in green light start time between traffic light information and image data. 11A to 11D are diagrams showing examples of display of recommended driving speed range information. 1A is a diagram showing an example of a display of green light start timing information, and FIGS. 1B and 1C are diagrams showing examples of display timing of waiting time in the green light start timing information; FIG. 13 is a diagram illustrating an example of a route search. 11A and 11B are diagrams illustrating an example of determining the localization during a green light period and the localization during a red light period. FIG. 1A is a diagram showing an example of specifying a green light period, and FIG. 1B is a diagram showing an example of specifying a red light period. FIG. 1 is a diagram showing an example of an intersection. FIG. 11 is a diagram illustrating an example of timing for correcting pseudo signal information. 10 is a flowchart illustrating an example of a server process performed by the server device according to the embodiment. 11 is a flowchart illustrating an example of a signal information error determination process performed by a server device according to an embodiment. 11 is a flowchart showing an example of a signal information correction process for a sensor-responsive traffic light by a server device according to an embodiment. 11 is a flowchart illustrating an example of a pseudo-signal information generating process performed by a server device according to an embodiment. 10 is a flowchart illustrating an example of a terminal process performed by the navigation device according to the embodiment. 5 is a flowchart showing an example of a driving support information presentation process performed by the navigation device according to the embodiment. 5 is a flowchart showing an example of a route search process performed by the navigation device according to the embodiment. 1A to 1C are diagrams showing an example of a vehicle passing by a traffic light; 1A to 1C are diagrams showing an example of two vehicles passing by a traffic light; 13 is a flowchart showing an example of a server process performed by a server device according to a modified example. 13 is a flowchart showing an example of a pseudo-signal information generating process by a server device according to a modified example. 10 is a flowchart showing an example of a terminal process performed by a navigation device according to a modified example.

First, an embodiment of the present application will be described with reference to FIG. 1. FIG. 1 is a block diagram showing an example of a schematic configuration of an information processing device according to an embodiment.

As shown in FIG. 1, the information processing device D according to the embodiment is configured to include a signal information acquisition means 1, an image information acquisition means 2, and a determination means 3.

In this configuration, the signal information acquisition means 1 acquires signal information that indicates the manner in which a traffic signal is changed when it is output by a traffic light.

The imaging information acquisition means 2 acquires imaging information obtained by capturing an image of a traffic light.

The determination means 3 determines whether or not there is a time difference between the manner in which the traffic signal changes indicated by the traffic signal information acquired by the traffic signal information acquisition means 1 and the manner in which the traffic signal changes output by the traffic light, as identified based on the imaging information acquired by the imaging information acquisition means 2.

As described above, the operation of the information processing device D according to the embodiment makes it possible to determine whether there is a time difference between the manner in which the traffic signal changes indicated by the traffic light information and the manner in which the traffic signal actually changes due to the traffic light.

Next, specific examples corresponding to the above-described embodiment will be described with reference to Figures 2 to 18. The examples described below are examples in which the embodiment is applied to a device constituting a driving assistance system.

FIG. 2 is a block diagram showing an example of a schematic configuration of a driving support system according to an embodiment. FIG. 3(a) is a block diagram showing an example of a schematic configuration of a server device according to an embodiment. FIG. 3(b) is a block diagram showing an example of a schematic configuration of a navigation device according to an embodiment. FIG. 4(a) is a diagram showing an example of a state in which a traffic light is imaged from a vehicle. FIG. 4(b) is a diagram showing an example of a difference in green light start time between traffic light information and image data. FIG. 5(a) to FIG. 5(d) are diagrams showing an example of a display of recommended driving speed range information. FIG. 6(a) is a diagram showing an example of a display of green light start timing information. FIG. 6(b) and FIG. 6(c) are diagrams showing an example of a display timing of a waiting time in the green light start timing information. FIG. 7 is a diagram showing an example of a route search. FIG. 8 is a diagram showing an example of a determination of a green light period localization and a red light period localization. FIG. 9(a) is a diagram showing an example of a green light period specification, and FIG. 9(b) is a diagram showing an example of a red light period specification. FIG. 10 is a diagram showing an example of a state of an intersection. FIG. 11 is a diagram showing an example of a timing of correction of pseudo traffic light information. Fig. 12 is a flowchart showing an example of server processing by the server device according to the embodiment. Fig. 13 is a flowchart showing an example of signal information error determination processing by the server device according to the embodiment. Fig. 14 is a flowchart showing an example of signal information correction processing for sensor-responsive traffic lights by the server device according to the embodiment. Fig. 15 is a flowchart showing an example of pseudo signal information generation processing by the server device according to the embodiment. Fig. 16 is a flowchart showing an example of terminal processing by the navigation device according to the embodiment. Fig. 17 is a flowchart showing an example of driving support information presentation processing by the navigation device according to the embodiment. Fig. 18 is a flowchart showing an example of route search processing by the navigation device according to the embodiment.
[1. Configurations of the driving assistance system, server device, and navigation device]
As shown in FIG. 2, the driving assistance system S according to the embodiment includes a server device 10 and a plurality of navigation devices 20. The server device 10 and each navigation device 20 are connected to a network 40. The network 40 may be, for example, the Internet. Each navigation device 20 is mounted on a vehicle 30. The server device 10 provides each navigation device 20 with information for assisting driving of the vehicle 30. The navigation device 20 performs processing for guiding the vehicle 30 to a destination and outputs information for assisting driving of the vehicle 30. Details of the server device 10 are shown in FIG. 3(a), and details of the navigation device 20 are shown in FIG. 3(b).

A traffic control center 50 is further connected to the network 40. The traffic control center 50 provides traffic information such as congestion information and traffic regulations, and also provides signal information for each of the multiple traffic lights 60 via multiple roadside units 70. Each traffic light 60 is a traffic light for vehicles. Each traffic light 60 is installed at an intersection, a junction, a crosswalk, etc. Each traffic light 60 outputs traffic signals such as a green light (a signal indicating permission to proceed), a red light (a signal indicating no proceeding), and a yellow light (a signal indicating no proceeding in principle). Each roadside unit 70 is installed at a position corresponding to the road, such as above the road or on the side of the road. The roadside unit 70 outputs signal information for the traffic light 60 by infrared rays or radio waves. For example, the roadside unit 70 outputs signal information for the traffic light 60 that is located in the traveling direction of the vehicle along the road on which the roadside unit 70 is installed. The traffic control center 50, each traffic light 60, and each roadside unit 70 are connected to a network 80. The traffic control center 50 and the network 80 constitute a system for utilizing the signal information of each traffic light 60. An example of such a system is the Traffic Signal Prediction System (TSPS).

The traffic light information indicates the manner in which the traffic signal output by the corresponding traffic light 60 changes. In other words, the traffic light information indicates how the traffic signal changes over time. For example, the traffic light information indicates the schedule of the start time, duration, etc. of each traffic signal. The traffic light information may include, for example, position information indicating the position of the intersection etc. corresponding to the traffic light 60, the difference between the current time and the time when the traffic light information was generated, the elapsed time from the time when the traffic light information was generated to the start of the cycle in which the traffic light changes, the minimum and maximum cycle length, the minimum and maximum green light start time, the minimum and maximum green light end time, the sensing permission state, etc. The green light start time is the time that elapses from the start of the cycle to the start of the green light output. The green light end time is the time that elapses from the start of the cycle to the end of the green light output.

As shown in FIG. 3(a), the server device 10 includes a control unit 11, a storage unit 12, and a communication unit 13. The control unit 11 and the communication unit 13 are connected via a bus 14.

The control unit 11 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The CPU reads and executes various programs stored in the ROM and the storage unit 12, causing the control unit 11 to execute each process described below.

The storage unit 12 is composed of a non-volatile memory such as a hard disk. Various programs for performing various processes by the server device 10 are stored in the storage unit 12. The various programs may be read from a recording medium via a drive device (not shown), for example, or may be downloaded from a predetermined server device via the network 40.

The memory unit 12 also stores map data. The map data may include node information indicating the positions of each point (node) such as an intersection and the roads (links) connected to those points, link information indicating the shape of each road and the positions of stop lines corresponding to traffic lights, position information indicating the positions of traffic lights, etc. The map data may be detailed data that can identify, for example, the area of a road or the area of each lane within a road.

The communication unit 13 controls communication with the vehicle 30 and the traffic control center 50 via the network 40. The server device 10 receives probe information (described later) from the vehicle 30 and traffic information from the traffic control center 50 via the network 40.

As shown in FIG. 3(b), the navigation device 20 includes a control unit 21, a memory unit 22, a communication unit 23, a display 24, a speaker 25, an input unit 26, and an interface unit 27. The control unit 21 to the interface unit 27 are connected via a bus 28.

The control unit 21 includes a CPU, a ROM, a RAM, etc. The CPU reads and executes various programs stored in the ROM and the memory unit 22, causing the control unit 21 to execute various processes described below.

The storage unit 22 is composed of a non-volatile memory such as a hard disk or a flash memory. Various programs for controlling the navigation device 20 are stored in the storage unit 22. The various programs may be read from a recording medium via a drive device (not shown), or may be downloaded from the server device 10 via the network 40.

Map data is also stored in the storage unit 22. The map data may be stored in advance in the storage unit 22, or part or all of the map data may be downloaded from the server device 10 as necessary to update the map data stored in the storage unit 22.

The communication unit 23 connects to the network 40 via a base station (not shown) by wireless communication to control communication with the server device 10 and to control inter-vehicle communication with other vehicles 30. The communication unit 23 also receives traffic information, etc., from a radio wave beacon (not shown).

The display 24 is, for example, a liquid crystal display, an organic EL (Electro-Luminescence) display, etc., and displays various information based on the control of the control unit 21. The speaker 25 outputs various sounds based on the control of the control unit 21. The input unit 26 is, for example, composed of a touch panel, buttons, switches, etc., and outputs a signal indicating the content of an operation by a passenger of the vehicle 30 to the control unit 21.

The interface unit 27 is connected to the camera 31, vehicle speed sensor 32, acceleration sensor 33, gyro sensor 34, GNSS sensor 35, and beacon receiver 36 mounted on the vehicle 30. The interface unit 27 performs interface processing between the navigation device 20 and the camera 31 to the beacon receiver 36.

The camera 31 is composed of, for example, a CCD (Charge Coupled Device) sensor, captures an image of the surroundings of the vehicle 30 including the traveling direction of the vehicle 30, and outputs image data to the interface unit 27. This image data may be a still image or a moving image. The vehicle speed sensor 32 detects the traveling speed of the vehicle 30 and outputs speed information indicating the detected speed to the interface unit 27. The acceleration sensor 33 detects the acceleration of the vehicle 30 and outputs acceleration information indicating the detected acceleration to the interface unit 27. The gyro sensor 34 detects the angular velocity of the vehicle 30 and outputs angular velocity information indicating the detected angular velocity to the interface unit 27. The GNSS sensor 35 uses the GNSS (Global Navigation Satellite System) to receive a signal transmitted from a navigation satellite (not shown), calculates the position of the vehicle 30 based on this signal, and outputs current position information (e.g., latitude, longitude, etc.) indicating the calculated position to the interface unit 27. The GNSS used may be, for example, the GPS (Global Positioning System), or another system. The beacon receiver 36 receives signal information transmitted from the roadside device 70 and outputs it to the interface unit 27.

The control unit 21 performs various driving assistance based on the traffic light information received by the beacon receiver 36. The control unit 21, for example, outputs information to assist the driver of the vehicle 30. For example, the control unit 21 outputs, based on the traffic light information, from the display 24 or the speaker 25, recommended driving speed range information indicating a range of speeds suitable for the vehicle 30 passing through the intersection, stop line, or other location corresponding to the traffic light 60. This speed range is the speed range during which the vehicle 30 passes through the intersection, stop line, or other location within the green light period. The green light period is the period during which the green light is output (the period during which the green light is turned on). In other words, the green light period is the period from when the output of the green light starts to when it ends, or the period during which the output of the green light continues.

The control unit 21 also outputs from the display 24 or the speaker 25 driving start support information based on the traffic light information, which supports timing the start of driving of the vehicle 30 stopped on the road to which the traffic light 60 corresponds because the traffic light 60 is outputting a red light. The driving start support information may include at least one of green light start timing information and warning information. The green light start timing information indicates the timing at which the traffic light output by the traffic light 60 changes from red to green. Specifically, the green light start timing information may indicate the waiting time from the current time until the traffic light changes from red to green. As a result, while the green light start timing information is being output, the waiting time decreases as time passes (the waiting time is counted down). The warning information indicates a warning to the vehicle 30 in the traveling direction. An example of warning information is a message such as "Please check ahead."

If the vehicle 30 is an autonomous vehicle, an autonomous driving system installed in the vehicle 30 may control the autonomous driving by referring to traffic light information.
[2. Functions of driving assistance system]
[2-1. Determining Errors in Signal Information]
Since the traffic light information indicates the start time and the scheduled duration of each traffic light of the traffic light 60, there is a possibility that a time difference occurs between the manner of change of the traffic light indicated by the traffic light information and the manner of change of the actual traffic light of the traffic light 60. For example, in order to give priority to a specific vehicle, the duration of the red or green light of the traffic light may be changed to a duration different from the duration indicated by the traffic light information. In addition, in an emergency, the traffic light may be forcibly changed by the traffic control center. In addition, problems in the system consisting of the traffic control center 50 to the network 80, delays in transmitting the signal information to the roadside device 70, aging of the traffic light 60, etc. may be considered. Therefore, the driving assistance system S may determine this time difference based on image information obtained by capturing an image of the traffic light 60 by the camera 31 mounted on the vehicle 30. The determination of the time difference may be performed by either the server device 10 or the navigation device 20.

First, as shown in FIG. 4(a), the navigation device 20 causes the camera 31 to capture an image of the traffic light 60. The navigation device 20 acquires image data obtained from the camera 31 by this imaging as imaging information. For example, the navigation device 20 identifies the current position of the vehicle, the road on which the vehicle 30 is located, the direction of travel of the vehicle, etc. based on information acquired from the vehicle speed sensor 32 to the GNSS sensor 35 and map data. Furthermore, when the navigation device 20 determines based on this information that the vehicle 30 has entered within a predetermined range of the traffic light 60 in the direction of travel along the road on which the vehicle 30 is currently located, it causes the camera 31 to start capturing images.

When the server device 10 determines the time difference, the navigation device 20 transmits to the server device 10 probe information including image data obtained by imaging with the camera 31, date and time information indicating the current date and time, current position information indicating the position of the vehicle 30, direction information indicating the traveling direction, and identification information of the navigation device 20. Here, when the navigation device 20 receives signal information of a traffic light 60 located in the traveling direction along the road on which the vehicle 30 is currently located from the roadside device 70, the navigation device 20 transmits the probe information together with the signal information. For example, the navigation device 20 may transmit the probe information and the signal information at a predetermined time interval (e.g., 0.1 second intervals, etc.). The navigation device 20 may recognize the traffic light 60 by pattern recognition from the image data and identify the color of the traffic light output from the traffic light 60 (the color of the lighted signal). The navigation device 20 may then transmit probe information including color information indicating the identified signal color as imaging information instead of image data.

The server device 10 acquires the probe information and traffic light information transmitted from the navigation device 20 via the network 40. The server device 10 determines whether there is a time difference between the state of the traffic light change indicated by the traffic light information and the state of the traffic light specified based on the image information included in the probe information. For example, the server device 10 specifies the green light start time or the red light start time based on the traffic light information. The green light start time is the time when the output of the green light starts, and the red light start time is the time when the output of the red light starts. The server device 10 specifies the traffic light color of the traffic light 60 by pattern recognition from the image data included in the probe information. The server device 10 specifies the actual green light start time or the red light start time based on the traffic light color specified from the series of probe information acquired from the navigation device 20 and the date and time information included in the probe information. The server device 10 compares the green light start time or the red light start time indicated by the traffic light information with the green light start time or the red light start time obtained from the probe information. Then, the server device 10 determines whether there is a difference between the two. For example, as shown in FIG. 4(b), the traffic light information indicates that the green light starts at time T1. On the other hand, the image data captured by the vehicle 30 indicates that the red light starts at time T2. In this case, the difference between times T1 and T2 is the error.

If the server device 10 determines that there is a time difference, the server device 10 may calculate the difference as an error of the traffic light information. The server device 10 may calculate the error for one traffic light 60 using only a series of probe information obtained once from one vehicle 30, or may calculate the error using probe information obtained from each of multiple vehicles 30 or probe information obtained multiple times from one vehicle. For example, the server device 10 calculates the error between the green light start time or red light start time specified from the probe information obtained from multiple vehicles or the probe information obtained multiple times and the green light start time or red light start time indicated by the traffic light information. The server device 10 may perform statistical processing of the error to calculate a representative value of the error. Examples of the representative value include the average value, median value, and mode value. The server device 10 may also generate accuracy information indicating the accuracy of the traffic light information based on the calculated error. For example, the server device 10 may calculate the average value, standard deviation, etc. of the error as the accuracy of the traffic light information. The server device 10 may calculate the level of accuracy based on the average value, standard deviation, etc. of the error, and generate accuracy information indicating this level. For example, the level may be calculated so that the smaller the average value is, the higher the level is, and the smaller the standard deviation is, the higher the level is. It can be said that the higher the accuracy indicated by the accuracy information is, the smaller the temporal difference is.

The server device 10 may store in the memory unit 12 the determination information indicating the determination result of whether or not there is a time difference, and the difference information indicating the time difference, in association with the specific information of the corresponding traffic light 60. The difference information may be either error information indicating a calculated error or a representative value thereof, or accuracy information. The specific information is the specific information of the traffic light 60. The specific information may be, for example, unique identification information that is given to the traffic light 60 in advance, or may be a combination of position information indicating the position of the traffic light 60 or the position of an intersection or the like to which the traffic light 60 corresponds, and direction information indicating the traveling direction to which the traffic light 60 corresponds.

The server device 10 may transmit the judgment information or difference information to the vehicle 30. For example, the server device 10 may transmit to the vehicle 30 moving on the road corresponding to the traffic light 60 for which the judgment information or difference information is generated. The server device 10 may transmit in response to a request from the navigation device 20. For example, the navigation device 20 transmits an information request to the server device 10 periodically or at a predetermined timing. The information request includes, for example, position information indicating the position of the vehicle 30, direction information indicating the traveling direction, etc. The server device 10 identifies the road on which the vehicle 30 is located and identifies the traffic light 60 located along the road in the traveling direction of the vehicle 30 based on the information included in the information request and the map data. Then, the server device 10 may transmit the judgment information or difference information stored in the memory unit 12 in association with the identified traffic light 60. The server device 10 may transmit judgment information or difference information for multiple traffic lights 60 together. For example, the server device 10 may transmit information about multiple traffic lights 60 installed along the road on which the vehicle 30 is located together. Alternatively, the server device 10 may transmit information about multiple traffic lights 60 within a predetermined range from the current position of the vehicle 30. Alternatively, if a travel route is set in the navigation device 20, the server device 10 may transmit information about the traffic lights 60 corresponding to each of some or all of the roads on the travel route.

When the navigation device 20 determines the time difference, the navigation device 20 acquires traffic light information received by the beacon receiver 36 from the roadside device 70. The navigation device 20 identifies the green light start time or the red light start time based on the traffic light information. The navigation device 20 also identifies the traffic light color of the traffic light 60 from the image data obtained from the camera 31, and identifies the green light start time or the red light start time as the time when the actual traffic light changed. The navigation device 20 also determines whether there is a time difference between the green light start time or the red light start time indicated by the traffic light information and the green light start time or the red light start time obtained based on the image data. The navigation device 20 may calculate the difference between the two as the error of the traffic light information. The navigation device 20 may also perform statistical processing of multiple errors obtained for one traffic light 60 by the vehicle 30 passing the same road multiple times, and calculate a representative value of the error. The navigation device 20 may also generate accuracy information based on the calculated error.

The navigation device 20 may store in the memory unit 22 the determination information indicating the result of the determination of whether or not there is an error, the error information indicating the calculated error or a representative value, or the accuracy information in association with the specific information of the corresponding traffic light 60.

The navigation device 20 may transmit the error information and the specific information of the traffic light 60 to the server device 10. The server device 10 may perform statistical processing of the error information received from the multiple vehicles 30 to calculate a representative value of the errors or generate accuracy information. The server device 10 may store the error information or accuracy information indicating the representative value of the errors in association with the specific information of the traffic light 60 in the storage unit 12. The server device 10 may transmit the error information or accuracy information to the navigation device 20.
[2-2. Determination of recommended driving speed range based on difference information]
The navigation device 20 may determine the recommended driving speed range based on difference information indicating a time difference between the state of the traffic signal change indicated by the traffic light information and the state of the traffic signal specified based on the imaging information included in the probe information. The recommended driving speed range is a range of speeds suitable for the vehicle 30 passing through the intersection, stop line, or other position corresponding to the traffic light 60.

The navigation device 20 acquires the difference information from the storage unit 22 or the server device 10. The navigation device 20 then determines the recommended driving speed range based on the difference information and the traffic light information received from the roadside device 70. Specifically, the navigation device 20 narrows the recommended driving speed range the greater the time difference indicated by the difference information. This allows the driver to drive the vehicle 30 so that it passes through intersections, etc. smoothly, even if there is an error in the traffic light information, by driving the vehicle 30 at a speed that conforms to the recommended driving speed range.

For example, the navigation device 20 identifies the green light period based on the traffic light information received from the roadside device 70. The navigation device 20 may narrow the green light period according to the time difference indicated by the difference information. For example, the navigation device 20 may determine the maximum green light start time by shifting the green light start time, which indicates the start time of the green light period, further into the future as the time difference indicated by the difference information is larger, and may determine the minimum green light end time by shifting the green light end time, which indicates the end time of the green light period, further into the past as the time difference indicated by the difference information is larger. For example, the navigation device 20 may calculate the maximum green light start time by adding a time length obtained by multiplying the error indicated by the error information by a predetermined coefficient to the green light start time, and may calculate the maximum green light end time by subtracting this time length from the green light end time. The navigation device 20 may narrow the green light period based on the accuracy information. For example, the navigation device 20 may narrow the green light period as the accuracy indicated by the accuracy information is lower.

The navigation device 20 may determine a range of driving speeds at which the vehicle 30 can pass the stop line corresponding to the traffic light 60 within the period indicated by the maximum green light start time and the minimum green light end time. For example, the navigation device 20 determines the distance from the current position of the vehicle 30 to the stop line corresponding to the traffic light 60 based on the current position information acquired from the GNSS sensor 35 or the information received from the roadside device 70. The navigation device 20 also calculates a first waiting time required from the current time to the maximum green light start time and a second waiting time required from the current time to the minimum green light end time. The navigation device 20 calculates the minimum value of the driving speed at which the vehicle 30 passes the distance to the stop line after the first waiting time has elapsed as the minimum value of the recommended driving speed. At this time, the navigation device 20 determines the minimum value of the recommended driving speed so that it is not less than the minimum regulation speed or a predetermined speed. The navigation device 20 also calculates the maximum value of the driving speed at which the vehicle 30 passes the distance to the stop line before the second waiting time has elapsed as the maximum value of the recommended driving speed. At this time, the navigation device 20 determines the maximum value of the recommended driving speed so as not to exceed the maximum speed limit. Note that instead of calculating the range of the recommended driving speed, the navigation device 20 may determine the recommended driving speed range based on a table that indicates the recommended driving speed in association with, for example, the distance to the stop line, the error, the first waiting time, or the second waiting time.

The navigation device 20 displays recommended driving speed range information indicating the determined recommended driving speed range on the display 24 or outputs it through the speaker 25. The recommended driving speed range information may be, for example, text information or graphics. Figures 5(a) and 5(b) show an example in which the recommended driving speed range information is displayed as text information on the display 24. For example, when the time difference is relatively small, "30 to 50 km/h" is displayed as the recommended driving speed range information 110, as shown in Figure 5(a). On the other hand, when the time difference is relatively large, "30 to 45 km/h" is displayed as the recommended driving speed range information 120, as shown in Figure 5(b).

The navigation device 20 may reduce the recognizability of the recommended driving speed range information as the time difference increases. Recognizability refers to the visibility or audibility of the information. When the recommended driving speed range information is displayed on the display 24, the navigation device 20 may lighten the outline, color, etc. of the driving speed range information as the time difference increases. When the recommended driving speed range information is output from the speaker 25, the navigation device 20 may output the driving speed range information at a lower volume as the time difference increases. Alternatively, the navigation device 20 may change the content indicated by the output information according to the time difference. For example, the navigation device 20 may increase the abstraction or ambiguity of the recommended driving speed range as the time difference increases. The higher the abstraction or ambiguity, the lower the recognizability of the recommended driving speed range information. For example, the abstraction or ambiguity of the recommended driving speed range information is higher than that of the recommended driving speed range information of 30 to 50 km/h. For example, when the recommended traveling speed range information is a graphic, the navigation device 20 may reduce the visibility of at least one of the maximum value and the minimum value of the recommended traveling speed range in the graphic as the time difference indicated by the difference information increases. The navigation device 20 may also display the graphic so that at least one of the maximum value and the minimum value of the recommended traveling speed range is ambiguously indicated as the time difference indicated by the difference information increases. FIG. 5(c) and FIG. 5(d) show an example of displaying the recommended traveling speed range information as a bar graph on the display 24. For example, when the time difference is relatively small, a bar graph 130 with relatively high visibility is displayed as shown in FIG. 5(c). The outline of the bar graph 130 is clear. The bottom of the bar graph 130 is located at 30 km/h, and the top is located at 50 km/h. On the other hand, when the time difference is relatively large, a bar graph 140 with relatively low visibility is displayed as shown in FIG. 5(d). The bottom of the bar graph 140 is located at 30 km/h, and the top is located at 50 km/h. However, as the speed approaches 50 km/h from around 45 km/h, the color and outline of the bar graph 140 become lighter. This indicates that while the maximum recommended speed calculated from the green light period identified from the traffic light information is 50 km/h, the maximum recommended speed determined as a result of narrowing the green light period based on the difference information is considerably smaller than 50 km/h. The navigation device 20 may widen the range in which the color or outline is lightened the greater the time difference, or may increase the degree to which the color or outline is lightened the greater the time difference.

As another example of changing the ease of recognition, the navigation device 20 may output recommended driving speed range information when the time difference indicated by the difference information is equal to or less than a predetermined value, and may not output recommended driving speed range information when the time difference exceeds the predetermined value.

The server device 10 may receive traffic light information from the navigation device 20 and determine the recommended traveling speed range and the visibility of the recommended traveling speed range information based on the traffic light information and the difference information. Then, the server device 10 may cause the navigation device 20 to output the recommended traveling speed range information.
[2-3. Control of output of driving start support information based on difference information]
The navigation device 20 may control the output of driving start support information including green light start timing information based on the difference information. The driving start support information is displayed on the display 24 or output by the speaker 25. For example, as shown in Fig. 6(a), green light start timing information 200 is displayed.

The navigation device 20 acquires the difference information from the storage unit 22 or the server device 10. The navigation device 20 may then lengthen the time between the timing at which the output mode of the driving start support information is changed and the timing at which the traffic light changes from red to green, as indicated by the traffic light information, the greater the time difference indicated by the difference information. In this case, the output mode may be whether or not to output information, or which information is output and which information is not output.

For example, the navigation device 20 may extend the time between the timing at which the output of the green light start timing information, which indicates the timing at which the traffic light changes from red to green, ends and the timing at which the traffic light changes from red to green, which is indicated by the traffic light information, the greater the time difference indicated by the difference information. As a result, the greater the time difference between the traffic light information and the actual traffic light 60 regarding the change in the traffic light, the earlier the driver can plan the timing to start the vehicle 30 without relying on the green light start timing information. Therefore, even if there is the above-mentioned time difference, the driver can start driving the vehicle 30 smoothly.

For example, when the time difference is relatively small, as shown in FIG. 6(b), the countdown of the waiting time starts 20 seconds before the green light indicated by the traffic light information and ends 5 seconds before. On the other hand, when the time difference is relatively large, as shown in FIG. 6(c), the countdown of the waiting time starts 20 seconds before the green light indicated by the traffic light information and ends 10 seconds before. It is desirable for the navigation device 20 to determine the timing for ending the green light start timing information so that there is a high probability that the output of the green light start timing information ends before the traffic light actually changes from red to green.

For example, the navigation device 20 may extend the time between the output timing of the attention information, which indicates a call for attention in the traveling direction of the vehicle 30, and the timing, indicated by the traffic light information, when the traffic light changes from red to green, the greater the time difference indicated by the difference information. In this way, the greater the time difference between the traffic light information and the actual traffic light 60 in terms of the changing state of the traffic light, the earlier the driver's attention can be directed to the traveling direction of the vehicle 30, allowing the driver to time the start of the vehicle 30.

For example, if the time difference is relatively small, as shown in FIG. 6(b), the warning message "Please check ahead" is output 5 seconds before the green light indicated by the traffic light information. On the other hand, if the time difference is relatively large, as shown in FIG. 6(c), the warning message is output 10 seconds before the green light indicated by the traffic light information.

Instead of or in addition to adjusting the time between the timing of changing the output mode of the driving start support information and the timing of the traffic light changing from red to green as indicated by the traffic light information, the navigation device 20 may lower the ease of recognition of the green light start timing information as the time difference indicated by the difference information becomes larger. As a result, the driver can measure the timing of starting the vehicle 30 without relying on the green light start timing information as the time difference between the traffic light information and the actual traffic light 60 regarding the change mode of the traffic light becomes larger. For example, when the green light start timing information is displayed on the display 24, the navigation device 20 may lighten the outline, color, etc. of the green light start timing information as the time difference becomes larger. When the green light start timing information is output from the speaker 25, the navigation device 20 may output the green light start timing information at a lower volume as the time difference becomes larger. Alternatively, the navigation device 20 may change the content indicated by the output information according to the time difference. For example, the navigation device 20 may increase the abstraction or ambiguity of the timing of the traffic light changing from red to green the greater the time difference. The higher the abstraction or ambiguity, the less easily recognizable the green light start timing information becomes. For example, as green light start timing information, "8 to 12 seconds left" has a higher abstraction or ambiguity than "10 seconds left," and "The light will soon turn green" has a higher abstraction or ambiguity than "8 to 12 seconds left."

As another example of changing the ease of recognition, the navigation device 20 may output the green light start timing information when the time difference indicated by the difference information is equal to or less than a predetermined value, and may not output the green light start timing information when the time difference exceeds the predetermined value. Furthermore, the navigation device 20 may output only the warning information without outputting the green light start timing information when the time difference exceeds the predetermined value. The navigation device 20 may or may not output the warning information when the time difference is equal to or less than the predetermined value.

The server device 10 may receive traffic light information from the navigation device 20, and determine the timing to end the output of the green light start timing information and the ease of recognition, based on the traffic light information and the difference information. Then, the server device 10 may cause the navigation device 20 to output the recommended driving speed range information.
[2-4. Route search based on difference information]
The driving assistance system S may perform a route search using the above-mentioned difference information. This route search may be performed by either the server device 10 or the navigation device 20. The following describes a case where the navigation device 20 performs a route search.

The navigation device 20 acquires the difference information from the storage unit 22 or the server device 10. The navigation device 20 searches for a route by increasing the priority of the road (link) corresponding to the traffic light 60 with a smaller time difference indicated by the difference information. As a result, when the driver drives the vehicle according to the recommended driving speed range information and the driving start support information output based on the traffic light information received from the roadside device 70, a route with a high possibility of smoothly passing through an intersection or the like is searched for. In this case, the priority is the degree to which the road of interest is preferentially selected as part of the route. For example, the navigation device 20 uses the travel cost of each road as the weight of the road and searches for a route with the smallest total travel cost, or a route with the smallest travel cost from the route with the smallest travel cost to the route with the second smallest travel cost using the Dijkstra algorithm or the like. Examples of factors that determine the travel cost include the distance of the road, whether the road is a toll road and the fee for use, the congestion status of the road, etc. The navigation device 20 calculates the travel cost taking into account the difference information. For example, the navigation device 20 increases the travel cost as the time difference indicated by the difference information increases. FIG. 7 is a diagram showing an example of a route search. It is assumed that the factors determining the travel cost other than the difference information are the same for all roads shown in FIG. 7. The driver of vehicle 30 has set point 310 as the destination. The time differences indicated by the difference information for roads 320 to 350 are all small. If vehicle 30 passes through roads 320 to 350 in this order to reach destination 310, the travel cost will be minimized. Therefore, navigation device 20 determines route 360, which includes roads 320 to 350, as the route to destination 310.

The navigation device 20 may output at least one route found by the above-mentioned route search from the display 24. The navigation device 20 accepts an operation from the passenger to select one of the at least one output route through the input unit 26. The navigation device 20 sets the route selected by the accepted operation as the travel route of the vehicle 30. The navigation device 20 performs processing to guide the vehicle 30 to the destination along the set travel route. If the vehicle 30 is an autonomous vehicle, the autonomous driving control system installed in the vehicle 30 performs autonomous driving along the searched travel route.

If the vehicle 30 stops while traveling along the set travel route, the navigation device 20 may re-execute the above-mentioned route search. The navigation device 20 may automatically set the route searched by re-executing the route search as the travel route of the vehicle 30, or may set the searched route as the travel route based on the selection of the passenger.

When the server device 10 performs a route search, the server device 10 obtains destination information indicating the destination from the navigation device 20, and searches for a route based on this destination information, the difference information stored in the memory unit 12, map data, etc.
[2-5. Correction of Signal Information of Sensor-Induced Signals]
In the case of a normal traffic light, the length of the green light period and the length of the red light period are generally fixed. Therefore, the lengths of the green light period and the red light period indicated by the traffic light information for such a traffic light are fixed (the minimum and maximum values included in the traffic light information are the same). However, a sensor-based traffic light detects a vehicle and switches between and outputs multiple traffic signals based on the presence or absence of the vehicle. Specifically, a sensor-based traffic light changes the duration of at least one of the green light and the red light based on the detection of a vehicle. Therefore, the lengths of the green light period and the red light period indicated by the traffic light information are set within a certain range (the minimum and maximum values included in the traffic light information are different). Therefore, the traffic light information of a sensor-based traffic light may not be able to appropriately assist the driving of the vehicle 30.

Therefore, the server device 10 may change or correct the signal information of the sensor-activated traffic light based on the imaging information obtained by capturing an image of the traffic light 60 by the camera 31 mounted on the vehicle 30. Specifically, the server device 10 generates trend information indicating the trend of traffic light changes caused by the traffic light 60 based on the imaging information. The server device 10 may specify the trend of the duration of the output of a certain traffic light as the trend of traffic light changes. For example, the navigation device 20 transmits the above-mentioned probe information about the sensor-activated traffic light to the server device 10. The server device 10 specifies the position of the green light period or red light period of the sensor-activated traffic light based on the signal color recognized by pattern recognition from the image data included in the probe information. The position of the period indicates the length of the period and indicates the position within the range of the length of the green light period or red light period indicated in the traffic light information. When the lengths of the multiple green light periods and the lengths of the multiple red light periods are obtained based on the probe information acquired from the multiple vehicles 30, the server device 10 specifies the trend of the position of the green light period and the red light period of the sensor-activated traffic light based on this information. For example, the server device 10 may calculate the average value and standard deviation of the length of the green light period and the length of the red light period as the localization tendency. Alternatively, the server device 10 may multiply the calculated standard deviation by a predetermined coefficient to obtain a time length, add the obtained time length to the average value, calculate the maximum value of the period length, and subtract this time length from the average value to calculate the minimum value of the period length, and consider the range from the calculated minimum value to the maximum value as the localization tendency. Alternatively, the server device 10 may calculate representative values such as the average value, median value, or mode value of the length of the green light period and the length of the red light period as the localization tendency. The server device 10 may store trend information indicating the localization tendency in the memory unit 12 in association with information for identifying a sensor-assisted traffic light.

The server device 10 may identify the orientation trends of the green light period and the red light period for each time period in which the traffic light is imaged, and generate trend information indicating these trends. The server device 10 may then store the trend information in the memory unit 12 in association with information for identifying the sensor-activated traffic light and the time period. This makes it possible to handle traffic lights 60 in which the trend of at least one of the length of the green light period and the length of the red light period changes due to changes in traffic volume depending on the time period.

The server device 10 changes or corrects the traffic light information of the sensor-responsive traffic light based on the generated trend information. The server device 10 acquires the traffic light information of the sensor-responsive traffic light to be corrected. For example, the server device 10 may acquire from the navigation device 20 the traffic light information received by the navigation device 20 from the roadside device 70. The server device 10 acquires trend information corresponding to the traffic light information from the storage unit 12. At this time, the server device 10 may acquire trend information associated with the time period during which the navigation device 20 received the traffic light information from the roadside device 70.

The server device 10 changes the traffic light information so that the length of the period corresponds to the trend indicated by the trend information within the range of the length of the green light period or red light period indicated by the traffic light information. For example, the server device 10 may determine the corrected time length or length range closer to the maximum value as the orientation indicated by the trend information as a trend is closer to the maximum value of the range of the period indicated by the traffic light information, and may determine the corrected time length or length range closer to the minimum value as the orientation indicated by the trend information as a trend is closer to the minimum value of the range of the period indicated by the traffic light information. For example, assume that the orientation of the green light period indicated by the trend information as a trend is closer to the maximum value than the minimum value, and the orientation of the red light period indicated by the trend information as a trend is closer to the minimum value than the maximum value. In this case, as shown in FIG. 8, the position of the length or length range of the green light period is determined closer to the maximum value, and the length or length range of the red light period is determined closer to the minimum value. The server device 10 may determine the length or length range of the period according to the orientation indicated by the trend information as a trend.

The server device 10 changes the minimum and maximum cycle length, the minimum and maximum green start time, the minimum and maximum green end time, etc., included in the traffic light information so that the traffic light information indicates the determined corrected lengths of the green light period and red light period. For example, the minimum and maximum green start time and the minimum and maximum green end time are information indicating the range of the green light period length. For example, this information and the minimum and maximum cycle length are information indicating the range of the red light period length.

The server device 10 transmits the corrected traffic light information to the vehicle 30. For example, the server device 10 may transmit the corrected traffic light information to the vehicle 30 that has transmitted the traffic light information as described above.

The navigation device 20 may specify the lengths of the red light period and the green light period based on image data obtained by capturing an image, specify a tendency of positioning based on the length of the period obtained by the vehicle 30 passing the sensor-activated traffic light multiple times, and correct the signal information of the sensor-activated traffic light received from the roadside unit 70 based on these tendencies. Alternatively, the navigation device 20 may receive tendency information generated by the server device 10, and perform correction based on the received tendency information.
[2-6. Generation of pseudo signal information]
The driving assistance system S may generate pseudo-signal information based on output status related information related to the output status of a traffic signal by the traffic light 60 and detected in the vehicle 30. The pseudo-signal information is information that substitutes for traffic light information. If the traffic light information transmitted from the roadside device 70 is the first traffic light information, the pseudo-signal information is the second traffic light information. The format of the pseudo-signal information may be the same as the format of the traffic light information. The output status related information may be imaging information. The imaging information indicates the output status of a traffic signal by the traffic light 60. The pseudo-signal information may be generated by either the server device 10 or the navigation device 20. Since pseudo-signal information can be generated even for roads where traffic light information is not distributed, it is possible to support the driving of the vehicle 30 by providing pseudo-signal information to the vehicle 30 traveling on a road where traffic light information is not distributed.

When the server device 10 generates pseudo traffic light information, the navigation device 20 transmits the probe information described in Section 2-1 to the server device 10. The navigation device 20 transmits the probe information in real time (for example, at 0.1 second intervals). The server device 10 identifies the green light period and the red light period for each traffic light 60 based on the probe information. For example, the server device 10 may identify the time when the green light and the red light started, respectively, based on a series of probe information acquired from one vehicle 30, and identify the green light period or the red light period based on the identified time. For example, as shown in FIG. 9(a), from the traffic light color identified by pattern recognition from the image data, the red light changes to a green light at time T11, and then the green light changes to a red light at time T12. Therefore, the green light period is the period from time T11 to T12. Similarly, as shown in FIG. 9(b), from the traffic light color identified from the image data, the green light changes to a red light at time T21, and then the red light changes to a green light at time T22. Therefore, the red light period is the period from time T21 to T22. The navigation device 20 may identify the green light period or the red light period based on probe information acquired from multiple vehicles 30. For example, when multiple vehicles 30 are traveling on the same road at a certain interval, a camera 31 mounted on one vehicle 30 may capture an image of the traffic light 60 when the light changes from red to green, and then a camera 31 mounted on another vehicle 30 may capture an image of the traffic light 60 when the light changes from green to red. In this case, the green light period can be identified based on the probe information acquired from these vehicles 30.

The server device 10 generates pseudo-signal information based on the identified green light periods and red light periods. For example, the server device 10 determines information such as the difference between the current time and the time when the signal information was generated, the elapsed time from the time when the signal information was generated to the start of the cycle in which the traffic signal changes, the cycle length, the start time of the green light, and the end time of the green light, based on the green light periods and red light periods. The server device 10 may store the pseudo-signal information including the determined information in the memory unit 12 in association with the specific information of the corresponding traffic light 60. When the server device 10 has identified multiple green light periods and multiple red light periods based on information obtained from multiple vehicles 30, it may perform statistical processing on each of the green light periods and red light periods to determine each piece of information included in the pseudo-signal information.

A road may have multiple lanes on one side, and the traffic light 60 corresponding to these lanes may change the traffic signal for at least one of these lanes in a manner different from that for the other lanes. For example, on a road with three lanes on one side, a right-turn signal corresponding to only the right lane may be provided on the traffic light 60. In this case, the server device 10 may generate pseudo-signal information for the at least one lane and the other lanes. In the above example, pseudo-signal information for the two lanes on the left side and pseudo-signal information for the one lane on the right side are generated. Alternatively, the server device 10 may generate pseudo-signal information for each lane. The server device 10 may store the generated pseudo-signal information in the memory unit 12 in association with information for identifying the corresponding traffic light 60 and lane, respectively.

The server device 10 may transmit the generated pseudo-signal information to the navigation device 20 mounted on the vehicle 30. The server device 10 may transmit, for example, in response to a request from the navigation device 20. For example, the navigation device 20 transmits an information request as described in Section 2-1 to the server device 10. Based on the information request and the map data, the server device 10 identifies a traffic light 60 corresponding to an intersection or the like ahead of the vehicle 30, and transmits pseudo-signal information associated with the identified traffic light 60 and stored in the memory unit 12. The server device 10 may transmit pseudo-signal information for multiple traffic lights 60. For example, the server device 10 may transmit pseudo-signal information for multiple traffic lights 60 installed along the road on which the vehicle 30 is located, all together. Alternatively, the server device 10 may transmit pseudo-signal information for multiple traffic lights 60 within a predetermined range from the current position of the vehicle 30. Alternatively, when a travel route is set in the navigation device 20, the server device 10 may transmit pseudo-signal information for the traffic lights 60 corresponding to some or all of the roads on the travel route. When the vehicle 30 is located on a road on which traffic light information cannot be received from the roadside device 70, the navigation device 20 that has received the pseudo-signal information may use the pseudo-signal information to execute a process to support the driving of the vehicle 30, such as outputting recommended driving speed range information and driving start support information. The navigation device 20 may also use the pseudo-signal information for route search. For example, the navigation device 20 estimates the time it will take the vehicle 30 to pass through an intersection, etc., and calculates the probability for each road that the vehicle 30 will pass through the intersection, etc. without stopping, based on the estimated time and the pseudo-signal information. The navigation device 20 searches for a route by giving a higher priority to roads with a higher probability.

In the case of a traffic light 60 in which the manner in which the traffic signal changes varies depending on the lane, the server device 10 may transmit pseudo-signal information for all lanes to the vehicle 30, for example. The navigation device 20 may identify the lane in which the vehicle 30 is located, for example, based on image data obtained by photographing with the camera 31. Alternatively, if the accuracy of the GNSS sensor 35 and the map data is high, the navigation device 20 may identify the lane in which the vehicle 30 is located, based on the current position information and map data obtained from the GNSS sensor 35. Alternatively, when the vehicle 30 is traveling along a route searched by the navigation device 20, the navigation device 20 may estimate the traveling direction of the vehicle 30 from an intersection or the like based on the set route, and may estimate the lane in which the vehicle 30 is located on the road entering the intersection or the like based on this traveling direction. If the server device 10 or the navigation device 20 stores the history of the travel route of the vehicle 30, the navigation device 20 may estimate the travel direction of the vehicle 30 from an intersection or the like based on the travel route history, and may estimate the lane in which the vehicle 30 is located on the road entering the intersection or the like based on the travel direction. The navigation device 20 may execute a process to assist the driving of the vehicle 30 by using pseudo signal information for the identified or estimated lane.

When the navigation device 20 generates pseudo-signal information, the navigation device 20 identifies the green light period and the red light period in the same manner as the server device 10, for example, based on image data from the camera 31. In order to identify both the green light period and the red light period for one traffic light 60, the vehicle 30 usually needs to pass the same road multiple times. The navigation device 20 may store the generated pseudo-signal information in the storage unit 22 in association with the identification information of the corresponding traffic light 60. The navigation device 20 may also transmit the pseudo-signal information to vehicles 30 around the vehicle 30 on which the navigation device 20 is mounted, by vehicle-to-vehicle communication. The navigation device 20 of the vehicle 30 that receives the pseudo-signal information can obtain the pseudo-signal information of the traffic light 60 even when the vehicle 30 is traveling at a position away from the traffic light 60 or at a position where the traffic light 60 cannot be seen (for example, the traffic light 60 is around a corner), so that information about the traffic light output from the traffic light 60 (for example, "The traffic light is currently red") can be output in advance. Additionally, as described above, the navigation device 20 can use pseudo-signal information in route searches.

In this embodiment, the driving assistance system S uses traffic light information, but even a system that does not use traffic light information can generate and use pseudo traffic light information.
[2-7. Estimation of green or red light period for generating pseudo traffic light information]
However, even if multiple pieces of image information are obtained for one traffic light 60, it may be difficult to identify the period during which a given signal output continues. For example, when the traffic light 60 is turning on the red light, the vehicle 30 is stopped, so the camera 31 mounted on the vehicle 30 has relatively many opportunities to capture the traffic light changing from green to red and then from red to green. Therefore, it is relatively easy to identify the red light period. On the other hand, when the traffic light 60 is turning on the green light, the vehicle 30 passes through, so the camera 31 has relatively few opportunities to capture the traffic light changing from green to red. Therefore, it is relatively difficult to identify the green light period. In particular, in the case of a road with low traffic volume, it may be difficult to identify the green light period using the image information obtained from multiple vehicles 30 as described above.

Here, there are a first road and a second road intersecting at a point such as an intersection, and a traffic light 60 corresponding to a vehicle proceeding from the first road at the point is defined as a first traffic light, and a traffic light 60 corresponding to a vehicle proceeding from the second road at the point is defined as a second traffic light. Then, consider generating pseudo traffic light information for the second traffic light. The server device 10 acquires output status related information related to the output status of a traffic signal by the first traffic light, which is detected in the vehicle 30, as described in Section 2-6. For example, the server device 10 acquires image data obtained by capturing an image of the first traffic light from the vehicle 30 traveling on the first road. Furthermore, the server device 10 specifies the period during which the output of the first traffic light, either a green light or a red light (e.g., a red light), continues at the first traffic light based on the acquired output status related information, as described in Section 2-6. Based on the identified period, the server device 10 estimates the period during which the second signal (e.g., a green signal) of either a green signal or a red signal will continue to be output at the second traffic light. Basically, when a red signal is being output from a traffic light 60 corresponding to a road, a green signal is being output from a traffic light 60 corresponding to a road intersecting the road. Therefore, the above-mentioned estimation is possible.

The server device 10 may estimate the red light period of the first traffic light, and estimate the green light period of the second traffic light based on this red light period. The server device 10 may also estimate the green light period of the first traffic light, and estimate the red light period of the second traffic light based on this green light period. The server device 10 may also do both.

For example, as shown in FIG. 10(a), traffic lights 60-1 to 60-4 are installed at a certain intersection. Traffic light 60-1 corresponds to vehicles moving north on road 501 extending in a north-south direction, and traffic light 60-2 corresponds to vehicles moving south. Traffic light 60-3 corresponds to vehicles moving east on road 502 extending in an east-west direction, and traffic light 60-4 corresponds to vehicles moving west. Currently, vehicle 30 is stopped in front of the stop line corresponding to traffic light 60-1, and a camera 31 mounted on vehicle 30 is capturing an image of traffic light 60-1. As shown in FIG. 10(b), based on image data from camera 31, a red light start time T31 and a green light end time T32 are respectively identified. Based on the red light period of traffic light 60-1 indicated by times T31 and T32, the green light periods of traffic lights 60-3 and 60-4 can be estimated. For example, the server device 10 estimates the green light start time T41 of the traffic light 60-3 based on the time T31, and estimates the green light end time T42 of the traffic light 60-3 based on the time T32. The time T41 may be, for example, the same as the time T31 or a predetermined number of seconds after the time T31. The end time T42 may be, for example, the same as the time T32 or a predetermined number of seconds after the time T32.

The server device 10 generates pseudo-signal information for the second traffic light based on the period estimated for the second traffic light. Specifically, the server device 10 acquires output status relation information related to the output status of the traffic signal by the second traffic light, which is detected in the vehicle 30. The server device 10 also estimates the period during which the output of the first signal (e.g., a red light) continues at the second traffic light based on the acquired output status relation information. The server device 10 then generates pseudo-signal information for the second traffic light based on the period during which the output of the first signal continues and the period during which the output of the second signal continues (i.e., the green light period and the red light period) estimated for the second traffic light. When the period during which the output of the second signal continues is estimated based on the output status relation information for the second traffic light, the server device 10 may further use this estimated period to generate pseudo-signal information.

The navigation device 20 may receive the pseudo signal information generated in this manner from the server device 10 and use it, as described in Section 2-6. Alternatively, the navigation device 20 may generate the pseudo signal information. Alternatively, the navigation device 20 may transmit the pseudo signal information by vehicle-to-vehicle communication.
[2-8. Correction of pseudo signal information based on signal information]
To improve the accuracy of the false signal information generated as described above, the navigation device 20 may correct the false signal information based on the signal information.

For example, the navigation device 20 may rewrite the elapsed time from the generation time of the traffic light information to the start of the cycle in which the traffic light changes, the length of the cycle, the start time of the green light, the end time of the green light, etc., contained in the pseudo traffic light information, with information contained in the traffic light information. The navigation device 20 may perform correction at the timing when it becomes possible to acquire both the traffic light information and the pseudo traffic light information, during the period when it becomes possible to acquire both the traffic light information and the pseudo traffic light information, or at the end of the period when it becomes possible to acquire both the traffic light information and the pseudo traffic light information. The period when traffic light information can be acquired is the period when the vehicle 30 is located in a section where the traffic light information of the target traffic light can be received from the roadside device 70. The period when pseudo traffic light information can be acquired is the period when the pseudo traffic light information of the target traffic light is generated and the navigation device 20 can connect to the server device 10 via the network 40. For example, as shown in FIG. 11, it is assumed that the vehicle 30 enters a section where traffic light information can be received while it is in a state where it is possible to receive pseudo traffic light information. The navigation device 20 may correct the pseudo traffic light information based on the traffic light information received from the roadside device 70 at this time. After the vehicle 30 leaves the section where it can receive traffic light information, the navigation device 20 uses the corrected pseudo signal to perform processing to assist the driving of the vehicle 30.

The navigation device 20 may use the pseudo signal information corrected in this manner as described in Section 2-6, or may transmit it to another vehicle 30 via vehicle-to-vehicle communication.

Also, the server device 10 may correct the pseudo signal information. For example, at a timing when the navigation device 20 becomes able to acquire both the signal information and the pseudo signal information, the navigation device 20 transmits the signal information and the pseudo signal information to the server device 10. The server device 10 corrects the pseudo signal information acquired from the navigation device 20 based on the signal information acquired from the navigation device 20. Then, the server device 10 transmits the corrected pseudo signal information to the navigation device 20.
[3. Operation of the driving assistance system]
Next, a description will be given of an example of the operation of the server device 10 and the navigation device 20. The processes shown in Figures 12 to 15 are executed by the server device 10, and the processes shown in Figures 16 to 18 are executed by the navigation device 20.

The server process shown in FIG. 12 is started when, for example, the server device 10 is powered on. First, the control unit 11 determines whether or not both probe information and traffic light information have been received from any vehicle 30 (step S101). If the control unit 11 determines that neither probe information nor traffic light information has been received (step S101: NO), the process proceeds to step S109. On the other hand, if the control unit 11 determines that both probe information and traffic light information have been received (step S101: YES), the process proceeds to step S102.

In step S109, the control unit 11 determines whether or not only probe information has been received from any vehicle 30. If the control unit 11 determines that probe information has been received (step S109: YES), the process proceeds to step S105. On the other hand, if the control unit 11 determines that probe information has not been received (step S109: NO), the process proceeds to step S106.

In step S102, the control unit 11 determines whether the received signal information is a sensor-activated traffic light. For example, this determination can be made based on the sensor-activated state included in the signal information, or on information about the traffic light included in the map data. If the control unit 11 determines that the received signal information is not a sensor-activated traffic light (step S102: NO), the process proceeds to step S103.

In step S103, the control unit 11 executes a traffic light information error determination process. As shown in FIG. 13, in the traffic light information error determination process, the control unit 11 specifies the green light start time or the red light start time based on the image data and date and time information included in the received probe information (step S201). Next, the control unit 11 compares the green light start time or the red light start time indicated by the received traffic light information with the green light start time or the red light start time specified based on the probe information in step S201 (step S202). Then, the control unit 11 determines whether there is a difference between the start time indicated by the traffic light information and the start time specified from the probe information (step S203). If the control unit 11 determines that there is a difference (step S203: YES), the control unit 11 proceeds to step S204. In step S204, the control unit 11 calculates the difference between the green light start time or the red light start time indicated by the traffic light information and the green light start time or the red light start time specified based on the probe information in step S201 as an error, and proceeds to step S205. On the other hand, if the control unit 11 determines that there is no difference (step S203: NO), the process proceeds to step S209. In step S209, the control unit 11 determines the error to be 0, and the process proceeds to step S205.

In step S205, the control unit 11 stores the error information indicating the error calculated in step S204 or the error determined in step S209 in the memory unit 12 in association with the specific information of the traffic light 60 to which the traffic light information corresponds (step S205).

Next, the control unit 11 determines whether the amount of error information stored in association with the specific information of the traffic light 60 described above is equal to or greater than a predetermined number (step S206). If the control unit 11 determines that the amount of error information is not equal to or greater than the predetermined number (step S206: NO), it ends the traffic light information error determination process. On the other hand, if the control unit 11 determines that the amount of error information is equal to or greater than the predetermined number (step S206: YES), it proceeds to step S207.

In step S207, the control unit 11 calculates the accuracy of the traffic light information based on the stored error information. The control unit 11 then associates the accuracy information indicating the calculated accuracy with the specific information of the traffic light 60 and stores it in the storage unit 12 (step S208), and ends the traffic light information error determination process.

In step S102 shown in FIG. 12, if the control unit 11 determines that the received signal information is signal information of a sensor-activated traffic light (step S102: YES), the control unit 11 proceeds to step S104.

In step S104, the control unit 11 executes a signal information correction process for a sensor-based traffic light. As shown in FIG. 14, in the signal information correction process for a sensor-based traffic light, the control unit 11 identifies the location of the green light period or the red light period based on the image data and date and time information included in the received probe information (step S301). Next, the control unit 11 stores in the memory unit 12 the green light location information indicating the location of the identified green light period or the red light location information indicating the location of the red light period in association with the specific information of the sensor-based traffic light corresponding to the received traffic light information and the time zone corresponding to the current time (step S302).

Next, the control unit 11 determines whether the total number of pieces of green light positioning information and red light positioning information stored in association with the specific information and the time period corresponding to the current time is equal to or greater than a predetermined number (step S303). If the control unit 11 determines that the total number is not equal to or greater than the predetermined number (step S303: NO), it ends the signal information correction process for sensor-activated traffic lights. On the other hand, if the control unit 11 determines that the total number is equal to or greater than the predetermined number (step S303: YES), it proceeds to step S304.

In step S304, the control unit 11 identifies the orientation tendency for each of the green light period and the red light period based on the green light orientation information and the red light orientation information stored in association with the specific information and the time period corresponding to the current time. For example, the control unit 11 may calculate the average value and standard deviation of the period length as the orientation tendency, or may calculate the range of the period length based on these average values and standard deviations, or may calculate a representative value of the period. Next, the control unit 11 stores the tendency information indicating the identified orientation tendency in the memory unit 12 in association with the specific information and the time period corresponding to the current time (step S305).

Next, the control unit 11 corrects the received traffic light information based on the trend information stored in the memory unit 12 (step S306). For example, the control unit 11 may match the range of lengths of the green light period and the red light period indicated by the traffic light information to the lengths or ranges of lengths of the green light period and the red light period indicated as a trend by the trend information. The control unit 11 transmits the corrected traffic light information to the vehicle 30 that transmitted the uncorrected traffic light information (step S307), and ends the traffic light information correction process for the sensor-assisted traffic light.

As shown in FIG. 12, when the signal information error determination process (step S103), the signal information correction process for sensor-based traffic lights (step S104), or only probe information is received from the vehicle 30 (step S109: YES), the control unit 11 executes the pseudo signal information generation process (step S105). As shown in FIG. 15, in the pseudo signal information generation process, the control unit 11 identifies the green light period or red light period of the target traffic light based on the image data and date and time information included in the received probe information (step S401). The target traffic light is the traffic light 60 for which pseudo signal information is to be generated, which is identified based on, for example, the position information and direction information included in the probe information. Next, the control unit 11 associates the green light period information indicating the identified green light period or the red light period information indicating the red light period with the identification information of the target traffic light and stores it in the memory unit 12 (step S402).

The control unit 11 then identifies, as a reference traffic light, a traffic light installed at the intersection where the target traffic light is installed and corresponding to a road that intersects with the road to which the target traffic light corresponds at the intersection. The control unit 11 acquires red light period information that is stored in association with the identification information of the reference traffic light (step S403). The control unit 11 then estimates the green light period of the target traffic light based on each acquired red light period information (step S404). The control unit 11 then generates green light period information that indicates the estimated period.

Next, the control unit 11 acquires green light period information stored in the memory unit 12 in association with the specific information of the reference traffic light (step S405). Next, the control unit 11 estimates the red light period of the target traffic light based on each acquired green light period information (step S406). Then, the control unit 11 generates red light period information indicating the estimated period.

Next, the control unit 11 determines whether the total number of the green light period information and red light period information stored in the memory unit 12 in association with the specific information of the target traffic light, and the green light period information and red light period information generated in steps S404 and S406, is equal to or greater than a predetermined number (step S407). If the control unit 11 determines that the total number is not equal to or greater than the predetermined number (step S407: NO), it ends the pseudo-signal information generation process. On the other hand, if the control unit 11 determines that the total number is equal to or greater than the predetermined number (step S407: YES), it proceeds to step S408.

In step S408, the control unit 11 generates pseudo signal information based on the green light period information and the red light period information. For example, the control unit 11 calculates a representative value of the green light duration indicated by the green light period information and a representative value of the red light duration indicated by the red light period information as the green light duration and the red light duration indicated by the pseudo signal information. The representative value may be, for example, an average value, a median value, a mode value, or the like. The control unit 11 also determines the cycle length based on the calculated duration. The control unit 11 also estimates the start time of the cycle based on, for example, the green light start time indicated by the green light period information. The control unit 11 generates pseudo signal information indicating these pieces of information. The control unit 11 associates the generated pseudo signal information with the specific information of the target traffic light and stores it in the storage unit 12 (step S409), and ends the pseudo signal information generation process.

When the control unit 11 finishes the pseudo signal information generation process, as shown in FIG. 12, it determines whether or not an information request has been received from any vehicle 30 (step S106). If the control unit 11 determines that an information request has not been received (step S106: NO), it proceeds to step S108. On the other hand, if the control unit 11 determines that an information request has been received (step S106: YES), it proceeds to step S107.

In step S107, the control unit 11 transmits at least one of the accuracy information and the pseudo signal information to the vehicle 30 in response to the information request. For example, the control unit 11 identifies at least one traffic light 60 to which information is to be transmitted, based on the map data and the location information included in the information request. If the accuracy information of the identified traffic light 60 is stored in the memory unit 12, the control unit 11 transmits the accuracy information. Furthermore, if the pseudo signal information of the identified traffic light 60 is stored in the memory unit 12, the control unit 11 transmits the pseudo signal information.

Next, the control unit 11 determines whether the power of the server device 10 has been turned off (step S108). If the control unit 11 determines that the power has not been turned off (step S108: NO), the process proceeds to step S101. On the other hand, if the control unit 11 determines that the power has been turned off (step S108: YES), the control unit 11 ends the server process.

The terminal process shown in FIG. 16 is started when, for example, the navigation device 20 is powered on. First, the control unit 21 transmits an information request to the server device 10 (step S501). Next, the control unit 21 receives at least one of the accuracy information and the pseudo signal information transmitted from the server device 10 in response to the information request (step S502). Then, the control unit 21 stores the received information in the memory unit 22 (step S503).

Then, the control unit 21 determines whether or not traffic light information has been received from any roadside unit 70 (step S504). If the control unit 21 determines that traffic light information has not been received (step S504: NO), the process proceeds to step S511. In step S511, the control unit 21 transmits probe information including image data etc. acquired from the camera 31 to the server device 10, and the process proceeds to step S512. On the other hand, if the control unit 21 determines that traffic light information has been received (step S504: YES), the process proceeds to step S505.

In step S505, the control unit 21 stores the received signal information in the storage unit 22. Next, the control unit 21 transmits the probe information and the received signal information to the server device 10 (step S506).

Then, the control unit 21 determines whether or not corrected signal information has been received from the server device 10 (step S507). If the control unit 21 determines that no signal information has been received (step S507: NO), the process proceeds to step S509. On the other hand, if the control unit 21 determines that signal information has been received (step S507: YES), the control unit 21 stores the received signal information in the storage unit 22 (step S508) and proceeds to step S509.

In step S509, the control unit 21 determines whether or not it is now possible to receive both signal information and pseudo signal information for the same traffic light 60. If the control unit 21 determines that it is not now possible to receive both signal information and pseudo signal information (step S509: NO), the process proceeds to step S512. On the other hand, if the control unit 21 determines that it is now possible to receive both signal information and pseudo signal information (step S509: YES), the control unit 21 corrects the pseudo signal information based on the signal information (step S510) and proceeds to step S512.

In step S512, the control unit 21 executes the driving support information presentation process. As shown in FIG. 17, in the driving support information presentation process, the control unit 21 identifies the traffic light 60 closest to the vehicle 30 among the traffic lights 60 located in the traveling direction of the vehicle 30 along the road on which the vehicle 30 is located, as the target traffic light, based on the current position and traveling direction of the vehicle 30 and the map data. The control unit 21 then determines whether or not the traffic light information of the target traffic light has been received (step S601). If the control unit 21 determines that the traffic light information has not been received (step S601: NO), the control unit 21 advances the process to step S610. On the other hand, if the control unit 21 determines that the traffic light information has been received (step S601: YES), the control unit 21 advances the process to step S602.

In step S602, the control unit 21 determines whether the vehicle 30 is stopped within a predetermined distance from the target traffic light because the target traffic light is outputting a red signal. For example, the control unit 21 may determine whether the target traffic light is outputting a red signal based on the signal information of the target traffic light. The control unit 21 may also determine whether the vehicle 30 is stopped within a predetermined distance from the stop line corresponding to the target traffic light based on the current position and traveling speed of the vehicle 30. If the control unit 21 determines that the vehicle 30 is not stopped because the target traffic light is outputting a red signal (step S602: NO), the control unit 21 proceeds to step S606. On the other hand, if the control unit 21 determines that the vehicle 30 is stopped because the target traffic light is outputting a red signal (step S602: YES), the control unit 21 proceeds to step S603.

In step S603, the control unit 21 specifies the green light start time of the target traffic light based on the traffic light information. For traffic light information of a sensor-responsive traffic light, the control unit 21 may specify the green light start time so that the green light start time is the shortest in the range of the period length indicated by the traffic light information. Next, the control unit 21 determines the time to end the display of the green light start timing information based on the green light start time and the accuracy information for the target traffic light (step S604). For example, a predetermined time before the green light start time is set as the reference time. The reference time is the time to end the display of the green light start timing information when the accuracy of the traffic light information is the highest. The control unit 21 determines a larger correction value as the accuracy indicated by the accuracy information becomes lower. For example, when the accuracy information includes the average value and standard deviation of the error, the control unit 21 may add the time length obtained by multiplying the standard deviation by a predetermined coefficient to the average value to calculate the maximum value of the error, and subtract this time length from the average value to calculate the minimum value of the error, and determine the absolute value of the error that is the largest within the range from the calculated minimum value to the maximum value as the correction value. The control unit 21 subtracts this correction value from the reference time to calculate the time to end the green light start timing information. Next, the control unit 21 displays the green light start timing information on the display 24 for the determined time, and ends the driving support information presentation process.

In step S606, the control unit 21 determines whether the vehicle 30 is moving based on the traveling speed of the vehicle 30. If the control unit 21 determines that the vehicle 30 is not moving (step S606: NO), the control unit 21 ends the driving assistance information presentation process. On the other hand, if the control unit 21 determines that the vehicle 30 is moving (step S606: YES), the control unit 21 advances the process to step S607.

In step S607, the control unit 21 identifies the green light period of the target traffic light based on the traffic light information. Next, the control unit 21 determines the recommended driving speed range based on the green light start time and green light end time identified from the green light period and the accuracy information for the target traffic light (step S608). For example, the lower the accuracy indicated by the accuracy information, the further in the future the control unit 21 shifts the green light start time to determine the maximum green light start time, and the further in the past the green light end time to determine the minimum green light end time. For example, the control unit 21 may determine a correction value in a manner similar to the method of determining the correction value in step S604, and determine the maximum green light start time by adding the correction value to the green light start time, and determine the minimum green light end time by subtracting the correction value from the green light end time. The control unit 21 determines the speed range in which the vehicle 30 passes the stop line corresponding to the target signal in the period from the maximum green light start time to the minimum green light end time. Next, the control unit 21 displays recommended driving speed range information indicating the determined speed range on the display 24 (step S609) and ends the driving assistance information presentation process.

In step S610, the control unit 21 displays green light start timing information or recommended driving speed range information on the display 24 based on the pseudo signal information of the target traffic light. For example, if the vehicle 30 is stopped because the target signal is outputting a red light, the control unit 21 calculates a reference time from the green light start time indicated by the pseudo signal information. The control unit 21 displays the green light start timing information on the display 24 until the current time reaches the reference time. In addition, if the vehicle 30 is traveling, the control unit 21 determines the speed range at which the vehicle 30 passes the stop line corresponding to the target signal within the green light period indicated by the pseudo signal information. The control unit 21 displays recommended driving speed range information indicating the determined speed range on the display 24. After completing step S610, the control unit 21 ends the driving support information presentation process.

When the driving assistance information presentation process is completed, as shown in FIG. 16, the control unit 21 determines whether the power of the navigation device 20 has been turned off (step S513). If the control unit 21 determines that the power has not been turned off (step S513: NO), the process proceeds to step S501. On the other hand, if the control unit 21 determines that the power has been turned off (step S513: YES), the control unit 21 ends the terminal process.

The route search process shown in FIG. 18 is started when the navigation device 20 receives an operation from the passenger to search for a destination. First, the control unit 21 sets the destination based on the operation from the passenger (step S701). Next, the control unit 21 searches for a route to the destination (step S702). Specifically, for each road to be followed for route search, the control unit 21 acquires accuracy information on the traffic lights 60 corresponding to the direction along the road. The control unit 21 calculates the travel cost of the road based on the distance, congestion status, accuracy information, etc. of the road. At this time, the higher the accuracy indicated by the accuracy information, the lower the travel cost. Then, the control unit 21 identifies a route with the smallest total travel cost. Next, the control unit 21 displays information indicating the route with the smallest total travel cost on the display 24 (step S703) and ends the route search process.

As described above, by the operation of the embodiment, when signal information is acquired, imaging information is acquired, and it is determined whether there is a time difference between the manner in which the traffic signal changes indicated by the acquired signal information and the manner in which the traffic signal changes identified based on the imaging information, it is possible to determine whether there is a time difference between the manner in which the traffic signal changes indicated by the signal information and the manner in which the traffic signal actually changes due to the traffic light 60.

Also, when calculating the time difference, it is possible to understand how much of a time difference there is.

In addition, when difference information indicating the calculated time difference is transmitted to a vehicle 30 traveling on the road corresponding to the traffic light 60, the vehicle 30 that uses the traffic light information can provide appropriate assistance to properly pass through the traffic light 60 based on the difference information.

In addition, when difference information for each of a number of traffic lights 60 installed along a road is collectively transmitted to the vehicle 30, assistance can be provided to help the vehicle 30 properly pass through the multiple traffic lights 60 along the road.

In addition, when accuracy information indicating the calculated accuracy is transmitted to a vehicle 30 traveling on the road corresponding to the traffic light 60, the vehicle 30 that uses the traffic light information can provide appropriate assistance to pass through the traffic light 60 appropriately based on the accuracy information.

In addition, when accuracy information for each of multiple traffic lights 60 installed along a road is collected and transmitted to the vehicle 30, assistance can be provided to help the vehicle 30 properly pass through the multiple traffic lights 60 along the road.

In addition, when difference information is acquired, a recommended driving speed range is determined based on the signal information and the difference information, the greater the time difference indicated by the difference information, the narrower the recommended driving speed range is determined, and recommended driving speed range information indicating the determined range is output by the display 24 or the speaker 25, even if there is a time difference between the signal information and the actual traffic light 60 regarding the change in the traffic signal, the driver can drive the vehicle 30 at a speed within the narrowed range, which increases the likelihood that the vehicle 30 will be able to smoothly pass the position on the road corresponding to the traffic light 60, and therefore information can be presented to assist the vehicle 30 in appropriately passing the position corresponding to the traffic light 60.

In addition, if the greater the time difference indicated by the difference information, the less easily the recommended driving speed range information can be recognized, the greater the time difference between the traffic signal information and the actual traffic light 60 in terms of the changing state of the traffic signal, the more likely the driver will drive the vehicle 30 without relying on the recommended driving speed range information, so that the decision on the driving speed can be left to the driver.

In addition, when recommended driving speed range information including a figure showing the recommended driving speed range is displayed on the display 24, and the greater the time difference shown by the difference information, the greater the decrease in visibility of at least one of the parts showing the maximum value and the minimum value of the recommended driving speed range in this figure. In this case, the greater the time difference between the traffic signal information and the actual traffic light 60 in terms of the change in the traffic signal, the driver will be able to drive the vehicle 30 without relying on information on at least one of the maximum and minimum values of the speed corresponding to the part with decreased visibility in the recommended driving speed range, so that the driver can be responsible for determining the driving speed.

In addition, if the recommended driving speed range information is not output when the time difference indicated by the difference information exceeds a predetermined value, if there is a significant time difference between the traffic signal information and the actual traffic signal 60 regarding the change in the traffic signal, the decision on the driving speed can be left to the driver.

In addition, the difference information is acquired, and based on the signal information and the difference information, driving start support information including green light start timing information is output by the display 24 or the speaker 25. If the time difference indicated by the difference information is greater, the time between the timing at which the output of the green light start timing information ends and the timing at which the traffic signal changes from red to green is lengthened, the greater the time difference between the signal information and the actual traffic light 60 regarding the change in the traffic signal, the earlier the timing at which the driver can direct his/her attention to the traveling direction of the vehicle 30 and check whether the traffic signal has changed to green without relying on the green light start timing information, and therefore the green light start timing information can be presented appropriately.

In addition, if the larger the time difference indicated by the difference information, the longer the time between when the output of the warning information begins and when the traffic signal changes from red to green, the larger the time difference between the traffic signal information and the actual traffic signal 60 in terms of the traffic signal change mode, the earlier the warning information can enable the driver to direct his/her attention to the direction of travel of the vehicle 30 and check whether the traffic signal has changed to green.

In addition, by acquiring difference information and outputting driving start support information including green light start timing information by the display 24 or speaker 25, and the greater the time difference indicated by the difference information, the less easily recognizable the green light start timing information is, the greater the time difference between the traffic light information and the actual traffic light 60 in terms of the traffic light change state is, so that the driver can determine the timing to start the vehicle 30 without relying on the green light start timing information, and therefore information regarding the timing at which the traffic light output from the traffic light 60 changes from red to green can be appropriately presented.

In addition, if the green light start timing information is not output when the time difference indicated by the difference information exceeds a predetermined value, and there is a significant time difference between the traffic signal information and the actual traffic light 60 regarding the traffic signal change mode, the driver can confirm whether the traffic signal has changed to a green light without relying on the green light start timing information.

In addition, when warning information is output when the time difference indicated by the difference information exceeds a predetermined value, if there is a significant time difference between the traffic signal information and the actual traffic light 60 regarding the traffic signal change, the warning information can be used to direct the driver's attention to the direction of travel of the vehicle 30, allowing the driver to check whether the traffic signal has changed to a green light.

In addition, when difference information is acquired and a search process is performed to search for a route along which the vehicle 30 will travel, with a higher priority being given to roads with smaller time differences indicated by the difference information, the travel route searched for is highly likely to include roads corresponding to traffic lights 60 with a relatively small time difference between the manner in which the traffic signal changes indicated by the traffic light information and the manner in which the traffic signal actually changes according to the traffic light 60. Therefore, a route along which the vehicle 30 can travel smoothly can be searched for based on the traffic light information.

In addition, if the vehicle 30 is moving along a route searched by the search process and then stops, when the search process is re-executed, an appropriate route can be searched for at the time the vehicle 30 stops.

In addition, when performing autonomous driving along the searched route, the vehicle 30 can automatically move smoothly along the route.

In addition, at least one of the searched routes is output, an operation to select one of the at least one output route is accepted, and the route selected by the accepted operation is set as the route along which the vehicle 30 will travel, whereby a route along which the vehicle 30 can travel smoothly can be set.

In addition, when imaging information obtained by imaging a sensor-based traffic light is acquired, and trend information showing the trend of traffic signal changes by the sensor-based traffic light is generated based on the acquired imaging information, and the signal information of the sensor-based traffic light is changed based on the generated trend information, the signal information can be appropriately changed taking into consideration the time difference between the manner of traffic signal changes indicated by the signal information for a sensor-based traffic light that switches between and outputs multiple traffic signals based on the vehicle detection results, and the manner of actual traffic signal changes by the sensor-based traffic light.

In addition, when the traffic light information includes range information indicating the range of time that the output of a specified traffic signal continues, trend information indicating the trend of the time that the output of the specified traffic signal continues is generated, and the range information is changed to indicate a time according to the trend indicated by the trend information within the time range indicated by the range information, the traffic light information can reflect the actual time that the output of the specified traffic signal continues.

In addition, when trend information is generated for each time period when the traffic light 60 is imaged, and the traffic light information is changed based on the trend information corresponding to the time period when the vehicle 30 received the traffic light information of the sensor-based traffic light from the roadside unit 70, the traffic light information can be changed appropriately for the sensor-based traffic light corresponding to the road where the traffic volume changes depending on the time period.

In addition, when output status relationship information is acquired and pseudo signal information is generated based on the acquired output status relationship information, the pseudo signal information can be generated as information in place of the signal information indicating the original schedule of the traffic signal changes, in order to provide it to vehicles 30 traveling on roads that cannot receive signal information.

In addition, when obtaining traffic signal output status relationship information from a first traffic light corresponding to a vehicle proceeding from a first road to a point where the first road and the second road intersect, identifying a period during which the output of a first signal continues at the first traffic light based on this output status relationship information, estimating a period during which the output of a second signal continues at a second traffic light corresponding to a vehicle proceeding from the second road to the aforementioned point based on the identified period, and generating pseudo signal information for the second traffic light based on the estimated period, it is possible to appropriately generate pseudo signal information that replaces signal information that shows the original schedule of traffic signal changes even when it is difficult to obtain output status relationship information that can identify the duration of the output of the second signal of the second traffic light.

In addition, when output status relationship information of the second traffic light is acquired, and the period during which the output of the first signal by the second traffic light continues is identified based on this output status relationship information, and pseudo signal information of the second traffic light is generated based on the estimated time during which the output of the first signal continues and the identified period during which the output of the second signal continues, the pseudo signal information can be generated appropriately.

In addition, if output status relationship information is acquired from multiple vehicles 30 for one traffic light 60 and the multiple acquired output status relationship information is subjected to statistical processing to generate pseudo signal information, more appropriate pseudo signal information can be generated.

In addition, when imaging information obtained by imaging the traffic light 60 from the vehicle 30 is acquired as output status related information, the output status of the traffic signal can be identified from the imaging information, so highly accurate pseudo-signal information can be generated.

In addition, for a traffic light that changes the traffic signal for at least one of a plurality of lanes in a manner different from that for the other lanes, when signal information is generated for the at least one lane and each of the other lanes, signal information can be appropriately generated for the traffic light that changes the traffic signal in a different manner depending on the lane.

In addition, if signal information is acquired, pseudo signal information is acquired, and the pseudo signal information is corrected based on the signal information, the accuracy of the pseudo signal information can be improved.

In addition, when the pseudo signal information is corrected at least at any one of the following times: when it becomes possible to obtain both signal information and pseudo signal information, during a period when it becomes possible to obtain both signal information and pseudo signal information, or at the end of a period when it becomes possible to obtain both signal information and pseudo signal information, the pseudo signal information can be corrected when it becomes possible to obtain both signal information and pseudo signal information.

In addition, when the server device 10 generates or corrects pseudo-signal information and transmits the generated or corrected signal information to a vehicle 30, the pseudo-signal information can be provided to multiple vehicles 30.

In addition, when the navigation device 20 generates or corrects pseudo-signal information and executes a process to assist the driving of the vehicle 30 based on the generated or corrected pseudo-signal information, driving assistance based on the pseudo-signal information becomes possible even in a system that does not use a network.

In addition, when the navigation device 20 transmits the generated or corrected pseudo-signal information to other vehicles 30 in the vicinity of the vehicle 30 equipped with this navigation device 20, driving assistance using the pseudo-signal information becomes possible in the other vehicles 30 as well.
[4. Modifications of pseudo signal information generation]
Next, a modified example of the generation of pseudo signal information described in Sections 2-6 and 2-7 will be described with reference to FIGS. 19 to 23. FIG.

FIGS. 19(a) to 19(c) are diagrams showing an example of a vehicle passing by a traffic light. FIGS. 20(a) to 20(c) are diagrams showing an example of two vehicles passing by a traffic light. FIG. 21 is a flowchart showing an example of server processing by a server device according to a modified example. FIG. 22 is a flowchart showing an example of pseudo-signal information generation processing by a server device according to a modified example. FIG. 23 is a flowchart showing an example of terminal processing by a navigation device according to a modified example.

In generating the pseudo traffic light information described in Section 2-6, the imaging information was used as the output status relation information. However, as the output status relation information, moving status information that indicates the moving status of the vehicle 30 detected in the vehicle 30 may be used. The moving status of the vehicle 30 may be affected by the output status of the traffic signal or may reflect the output status of the traffic signal. For example, when a red signal is output from the traffic light 60, the vehicle 30 stops moving, and when a green signal is output, the vehicle 30 moves and passes through an intersection or the like corresponding to the traffic light 60. The moving status is indicated by, for example, the position, speed, acceleration, angular velocity, traveling direction, and the like of the vehicle 30. For example, the probe information transmitted from the navigation device 20 to the server device 10 may include date and time information indicating the current date and time, current position information indicating the position of the vehicle 30, speed information indicating the speed, acceleration information indicating the acceleration, information indicating the angular velocity, direction information indicating the traveling direction, identification information of the navigation device 20, and the like. The navigation device 20 may always transmit the probe information to the server device 10 in real time. The server device 10 uses this probe information as moving status information.

The server device 10 estimates the green light period and red light period for each traffic light 60 based on the probe information acquired from the vehicle 30. In this modified example, it is possible to make an estimation using a series of probe information acquired once for one traffic light, but since the green light period and red light period are not directly identified, it is desirable to estimate the green light period and red light period by statistically processing the probe information acquired from multiple vehicles 30 for one traffic light.

The server device 10 may estimate the red light start time and the green light start time based on a series of probe information acquired from, for example, one vehicle 30, and may estimate the red light duration based on the estimated times. For example, when the probe information indicates that the vehicle 30 has stopped within a predetermined range according to the traffic light 60 and that the vehicle 30 has started to move after this stopping, the server device 10 may estimate the red light duration based on the period from this stopping to the start of movement. The predetermined range according to the traffic light 60 may be, for example, a range within a predetermined distance from the stop line corresponding to the traffic light 60. The server device 10 may then generate pseudo traffic light information based on the estimated red light duration.

For example, as shown in FIG. 19(a), vehicle 30 is traveling toward traffic light 60 that is outputting a green light. Then, as shown in FIG. 19(b), the traffic light changes to a red light, so vehicle 30 stops at the stop line. Then, as shown in FIG. 19(c), the traffic light changes to a green light, so vehicle 30 starts moving. Therefore, server device 10 may estimate the time when vehicle 30 stops as the red light start time, and may estimate the time when vehicle 30 starts moving as the green light start time. Then, server device 10 may estimate the period from when vehicle 30 stops to when it starts moving as the red light period.

The server device 10 may estimate the green light start time and the red light start time based on, for example, probe information acquired from each of two vehicles 30 or three or more vehicles 30, and may estimate the green light period based on the estimated times. For example, when the probe information indicates the start of movement of a first moving body within a predetermined range corresponding to the traffic light 60, and the stop of movement of another second moving body within a predetermined range corresponding to the traffic light 60 after the start of movement, the server device 10 may estimate the green light period based on the period from the start of movement to the stop of movement. Then, the server device 10 may generate pseudo traffic light information based on the estimated green light period.

For example, as shown in FIG. 20(a), the traffic light 60 is outputting a red signal, so the vehicle 30-1 is stopped at the stop line. Then, as shown in FIG. 20(b), the traffic light changes to a green signal, so the vehicle 30-1 starts moving. Meanwhile, the vehicle 30-2 is traveling toward the traffic light 60. Then, as shown in FIG. 20(c), the traffic light changes to a red signal, so the vehicle 30-2 stops at the stop line. Therefore, the server device 10 may estimate the time when the vehicle 30-1 starts moving as the time when the green signal starts, and the time when the vehicle 30-2 stops as the time when the red signal starts. The server device 10 may also estimate the period from when the vehicle 30-1 starts moving until when the vehicle 30-2 stops as the green signal period. Note that it may be determined from the probe information that the vehicle 30-2 stops moving after a considerable amount of time has passed since the vehicle 30-1 started moving. In this case, the traffic signal may have changed for at least one cycle or more between the time when vehicle 30-1 starts moving and when vehicle 30-2 stops moving after a considerable amount of time has passed. Therefore, server device 10 may not use probe information in which the time from when vehicle 30-1 starts moving until vehicle 30-2 stops exceeds a predetermined time, for estimating the green light period. Server device 10 may generate pseudo traffic light information based on the estimated red light period and green light period.

The server device 10 may estimate the green light period and the red light period in a manner similar to that described in Section 2-7. That is, the server device 10 estimates the period during which the first signal output continues at the first traffic light based on the probe information about the first traffic light, and estimates the period during which the second signal output continues at the second traffic light based on this period.

A road may have multiple lanes on one side, and a traffic light 60 corresponding to these lanes may change the traffic signal for at least one of these lanes in a manner different from that for the other lanes. Therefore, the server device 10 may generate pseudo-signal information for each of the at least one lane and the other lanes. Alternatively, the server device 10 may generate pseudo-signal information for each lane. The server device 10 needs to identify the lane in which the vehicle 30 that transmitted the probe information traveled. For example, the server device 10 may estimate which lane the vehicle 30 traveled in based on the movement status of the vehicle 30 indicated by the probe information. For example, the lanes may be divided according to the traveling direction from an intersection. Therefore, it is possible to estimate the lane in which the vehicle 30 traveled by identifying the direction in which the vehicle 30 traveled at the intersection. Also, for example, when the navigation device 20 searches for a travel route to a destination, the vehicle 30 may have traveled according to the searched travel route. Therefore, the server device 10 may obtain information indicating the travel route from the navigation device 20, and estimate the lane on which the vehicle 30 has traveled based on this information. Alternatively, if the accuracy of the GNSS sensor 35 and the map data is high, the server device 10 can identify the lane on which the vehicle 30 has traveled based on the current position information and map data obtained from the GNSS sensor 35.

Even if the vehicle 30 stops within a predetermined range according to the traffic light 60, the vehicle 30 may have stopped due to a factor other than the traffic light 60 outputting a red light. Therefore, the server device 10 does not need to use the probe information when the vehicle 30 may have stopped due to a factor other than the output of a red light, in generating the pseudo traffic light information.

For example, the server device 10 may obtain traffic information from the traffic control center 50. Then, based on the traffic information, the server device 10 may not use probe information detected in the vehicle 30 while the road on which the vehicle 30 is traveling is congested, for generating pseudo signal information. Note that, when the navigation device 20 determines, based on the traffic information, that the vehicle 30 is located on a congested road, the server device 10 may not need to transmit the probe information to the server device 10.

For example, the server device 10 may estimate whether or not the vehicle 30 may have stopped due to a factor other than the output of a red light, based on the movement status of the vehicle 30 indicated by the probe information. The server device 10 may not need to use the probe information when it is estimated that the vehicle 30 has stopped due to a factor other than the output of a red light, in generating the pseudo traffic light information.

For example, the server device 10 may not use probe information indicating that the vehicle 30 has started moving within a predetermined time after stopping with a deceleration exceeding a predetermined value, in generating pseudo-signal information. If the vehicle 30 starts moving immediately after stopping suddenly, the driver may have performed driving operations to avoid danger, such as avoiding a pedestrian that has run out onto the road.

For example, the server device 10 may not need to use probe information indicating that the vehicle 30 stopped near the edge of the road and then started moving after a relatively short time had passed in generating the pseudo-signal information. In such a case, the driver may have stopped the vehicle 30 so as not to prevent the emergency vehicle from traveling for an emergency purpose. Only when the server device 10 determines, based on probe information obtained from multiple vehicles 30 traveling on the same road at the same time, that a predetermined number or more of the vehicles 30 have traveled as described above, does the server device 10 need not use the probe information obtained from these vehicles 30 in generating the pseudo-signal information.

For example, when the server device 10 determines, based on the probe information obtained from the multiple vehicles 30, that the multiple vehicles 30 are traveling on a trajectory that is clearly different from normal and similar to each other, the server device 10 may not use the probe information to generate pseudo signal information. Examples of traveling on a trajectory that is different from normal include alternating one-way traffic and multiple vehicles 30 traveling around a single point. In such a case, there is a possibility that construction work is being carried out on the road on which the vehicles 30 are located, which may result in traffic restrictions.

The method of excluding probe information that may cause the vehicle 30 to stop due to an emergency vehicle traveling for an emergency purpose is not limited to the above-mentioned method. For example, the server device 10 may not use the probe information when the navigation device 20 detects that an emergency vehicle is traveling for an emergency purpose to generate pseudo-signal information. As an example of a method of detecting that an emergency vehicle is traveling for an emergency purpose, the emergency vehicle may transmit information indicating the emergency vehicle to surrounding vehicles by vehicle-to-vehicle communication, and the navigation device 20 may receive this information. In addition, for example, the navigation device 20 may analyze a sound collected by a microphone (not shown) mounted on the vehicle 30 to collect external sounds of the vehicle 30, and determine whether the sound of the siren of the emergency vehicle has been collected. When the navigation device 20 receives information indicating an emergency vehicle, or when it determines that the sound of a siren has been collected, the navigation device 20 may add information indicating the emergency vehicle to the probe information and transmit it to the server device 10. The server device 10 may not use the probe information to which the information indicating the emergency vehicle has been added to generate pseudo-signal information. Alternatively, if it is detected that an emergency vehicle is traveling for an emergency purpose, the navigation device 20 does not need to transmit the information to the probe information server device 10.

The navigation device 20 may receive and use the pseudo signal information generated as described above from the server device 10, as explained in Section 2-6. The navigation device 20 may also generate the pseudo signal information. In this case, it is preferable that the navigation device 20 generates the pseudo signal information by statistically processing probe information obtained multiple times for one traffic light 60. The navigation device 20 may also transmit the pseudo signal information via vehicle-to-vehicle communication.

Next, an example of the operation of the server device 10 and the navigation device 20 will be described. The processes shown in Figs. 21 and 22 are executed by the server device 10, and the process shown in Fig. 23 is executed by the navigation device 20.

In the server process shown in FIG. 21, the control unit 11 determines whether or not probe information has been received from any vehicle 30 (step S801). If the control unit 11 determines that probe information has not been received (step S801: NO), the process proceeds to step S805. On the other hand, if the control unit 11 determines that both probe information and traffic light information have been received (step S801: YES), the process proceeds to step S802.

In step S802, the control unit 11 stores the received probe information in the memory unit 12. Next, the control unit 11 identifies the traffic light 60 that is the subject of the pseudo signal information as the target traffic light, based on the current position information and direction information included in the probe information stored in step S802. The control unit 11 then determines whether or not there is a predetermined number or more of probe information stored in the memory unit 12 for the target traffic light (step S803). If the control unit 11 determines that there is not the predetermined number or more of probe information (step S803: NO), the control unit 11 proceeds to step S805. On the other hand, if the control unit 11 determines that there is the predetermined number or more of probe information (step S803: YES), the control unit 11 proceeds to step S804.

In step S804, the control unit 11 executes a pseudo-signal information generation process. As shown in FIG. 22, in the pseudo-signal information generation process, the control unit 11 acquires probe information of a vehicle that has passed through the road corresponding to the target traffic light from the memory unit 12 (step S901).

Next, the control unit 11 executes noise processing. In the noise processing, among the probe information acquired in step S901, probe information in which the vehicle 30 may have stopped due to factors other than the output of a red signal by the target traffic light is excluded as noise from the probe information used to generate the pseudo traffic light information. For example, the control unit 11 acquires traffic information from the traffic control center 50. Based on the traffic information, the control unit 11 excludes probe information in which the road corresponding to the target traffic light is congested at the date and time indicated by the date and time information included in the probe information. In addition, the control unit 11 excludes probe information in which the movement status indicated by the probe information may have caused the vehicle 30 to stop due to factors other than the output of a red signal. For example, the control unit 11 excludes probe information indicating that the vehicle 30 has started moving within a predetermined time after the vehicle 30 has stopped with a deceleration exceeding a predetermined value, as probe information indicating that the vehicle 30 may have stopped to avoid danger. Furthermore, when there is a predetermined number or more of probe information indicating that a predetermined number or more of vehicles 30 have stopped near the edge of the road at the same date and time, the control unit 11 excludes this probe information as probe information indicating that the vehicle may have stopped due to an emergency vehicle passing through for an emergency purpose. Furthermore, when there is a predetermined number or more of probe information indicating that a predetermined number or more of vehicles 30 are engaged in one-way alternating traffic or making a detour at one location, the control unit 11 excludes this probe information as probe information indicating that the vehicle may have taken a trajectory to avoid a construction site.

Next, the control unit 11 extracts, from the noise-processed probe information, probe information indicating that the vehicle 30 stopped near the stop line corresponding to the target traffic light and then started moving. Then, for each piece of extracted probe information, the control unit 11 estimates the time from when the vehicle 30 stopped to when it started moving as the red light period of the target traffic light (step S903).

Next, the control unit 11 extracts from the noise-processed probe information combinations that indicate that a first vehicle starts moving near the stop line corresponding to the target traffic light, and then a second vehicle stops near the stop line. For each of the extracted combinations, the control unit 11 estimates the time from when the first vehicle starts moving until the second vehicle stops as the green light period of the target traffic light (step S904).

The control unit 11 then identifies, as a reference traffic light, a traffic light installed at the intersection where the target traffic light is installed, corresponding to a road that intersects with the road to which the target traffic light corresponds. The control unit 11 acquires probe information of the reference traffic light from the memory unit 12 (step S905). The control unit 11 then performs noise processing on the probe information acquired in step S905 in a manner similar to that of step S902 (step S906).

Next, the control unit 11 extracts, from the probe information that has been subjected to noise processing in step S906, probe information indicating that the vehicle 30 has stopped near the stop line corresponding to the reference traffic light and then started moving. Then, for each piece of extracted probe information, the control unit 11 estimates the time from when the vehicle 30 stopped to when it started moving as the red light period of the reference traffic light (step S907).

Next, the control unit 11 estimates the green light period of the target traffic light based on each red light period estimated in step S907 (step S908). For example, the control unit 11 may estimate the green light start time of the target traffic light to be a predetermined time after the red light start time of the reference traffic light, and estimate the green light end time of the target traffic light to be a predetermined time before the red light end time of the reference traffic light.

Next, the control unit 11 extracts, from the probe information that has been subjected to noise processing in step S906, combinations of probe information that indicate that a first vehicle starts moving near the stop line corresponding to the target traffic light, and then a second vehicle stops near the stop line. Then, for each of the extracted combinations, the control unit 11 estimates the time from when the first vehicle starts moving until the second vehicle stops as the green light period of the reference traffic light (step S909).

Next, the control unit 11 estimates the red light period of the target traffic light based on each green light period estimated in step S909 (step S910). For example, the control unit 11 may estimate the red light start time of the target traffic light to be a predetermined time before the green light start time of the reference traffic light, and estimate the red light end time of the target traffic light to be a predetermined time after the green light end time of the reference traffic light.

Next, the control unit 11 generates pseudo signal information based on the green light periods estimated in steps S904 and S908 and the red light periods estimated in steps S903 and S910 (step S911). The method of generating the pseudo signal information is the same as that of step S408 shown in FIG. 15. The control unit 11 associates the generated pseudo signal information with the specific information of the target traffic light and stores it in the memory unit 12 (step S912), and ends the pseudo signal information generation process.

When the control unit 11 finishes the pseudo signal information generation process, as shown in FIG. 21, it determines whether or not an information request has been received from any vehicle 30 (step S805). If the control unit 11 determines that an information request has not been received (step S805: NO), it proceeds to step S807. On the other hand, if the control unit 11 determines that an information request has been received (step S805: YES), it proceeds to step S806.

In step S806, the control unit 11 transmits pseudo signal information to the vehicle 30 in response to the information request. The method of determining the pseudo signal information to transmit is the same as in step S107 of FIG. 12. Next, the control unit 11 determines whether the power of the server device 10 has been turned off (step S807). If the control unit 11 determines that the power has not been turned off (step S807: NO), the control unit 11 advances the process to step S801. On the other hand, if the control unit 11 determines that the power has been turned off (step S807: YES), the control unit 11 ends the server process.

In FIG. 23, the same processes as those in FIG. 16 are denoted by the same reference numerals. In the terminal process shown in FIG. 23, the control unit 21 transmits an information request to the server device 10 (step S501), receives pseudo signal information transmitted from the server device 10 (step S1001), and stores the received pseudo signal information in the storage unit 22 (step S1002).

Next, the control unit 21 executes step S505 according to the determination result of step S504. Next, the control unit 21 transmits probe information indicating the movement status of the vehicle 30 to the server device 10 (step S1003). Next, the control unit 21 executes step S508 according to the determination result of step S507.

Next, the control unit 21 identifies the traffic light 60 closest to the vehicle 30 among the traffic lights 60 located in the traveling direction of the vehicle 30 along the road on which the vehicle 30 is located, as the target traffic light, based on the current position and traveling direction of the vehicle 30 and the map data. Then, the control unit 21 determines whether or not the traffic light information of the target traffic light has been received (step S1004). If the control unit 21 determines that the traffic light information has been received (step S1004: YES), the process proceeds to step S1005. In step S1005, the control unit 21 displays the green light start timing information or the recommended driving speed range information on the display 24 based on the traffic light information of the target traffic light. In step S1005, the process is the same as step S610 shown in FIG. 17, except that the traffic light information is used. On the other hand, if the control unit 21 determines that the traffic light information has not been received (step S1004: NO), the process proceeds to step S1006. In step S1006, the control unit 21 causes the display 24 to display green light start timing information or recommended driving speed range information based on the pseudo signal information of the target traffic light, similar to step S610 shown in FIG. 17.

After completing step S1005 or step S1006, the control unit 21 advances the process to step S501 or ends the terminal processing based on the determination result of step S511.

As described above, according to the operation of the modified example, probe information indicating the movement status of the vehicle 30 is acquired as output status related information, and pseudo signal information is generated based on the acquired probe information. Therefore, pseudo signal information can be generated as information to replace the signal information and to provide it to the vehicle 30 traveling on roads where signal information cannot be provided.

In addition, when the probe information indicates that the vehicle 30 stops moving within a specified range corresponding to the traffic light 60 and then starts moving again after the stop, the red light period is estimated based on the period from the stop to the start of the movement, and pseudo signal information is generated based on the estimated red light period, so that appropriate pseudo signal information can be generated for the red light period.

In addition, when probe information is acquired from each of the first vehicle and the second vehicle, and this probe information indicates that the first vehicle has started moving within a specified range covered by the traffic light 60, and that the second vehicle has stopped moving within the specified range covered by the traffic light 60 after this movement has started, the green light period is estimated based on the period from the start of the movement to the stop of the movement, and pseudo signal information is generated based on the estimated red light period, so that appropriate pseudo signal information can be generated for the green light period.

In addition, if traffic information is acquired and probe information detected in the vehicle 30 when the road is congested based on this traffic information is not used to generate pseudo traffic light information, probe information detected in a situation where the vehicle 30 may be stopped due to congestion can be excluded, thereby improving the accuracy of the pseudo traffic light information.

In addition, if it is estimated based on the probe information whether the vehicle 30 has stopped due to a factor other than the output of a red light by the traffic light 60, and the probe information when it is estimated that the vehicle 30 has stopped due to a factor other than the output of a red light is not used to generate the pseudo-signal information, it is possible to exclude probe information that may not have caused the vehicle 30 to stop due to the output of a red light, thereby improving the accuracy of the pseudo-signal information.

In addition, if the probe information obtained when vehicle 30 detects that an emergency vehicle is moving for an emergency purpose near vehicle 30 is not used to generate the pseudo signal information, the accuracy of the pseudo signal information can be improved because the probe information detected in a situation where the driver may stop vehicle 30 to give way to the emergency vehicle can be excluded.

In the above embodiment and modified example, a navigation device is used as a device that provides driving assistance to the vehicle 30 based on at least one of the traffic light information and the pseudo traffic light information. However, the device that provides such driving assistance is not limited to a navigation device.

In the above examples and modified examples, the moving body of the embodiment is a vehicle. However, the moving body may be a motorcycle, a bicycle, a boat, or the like.

REFERENCE SIGNS LIST 1 Signal information acquisition means 2 Image capture information acquisition means 3 Determination means D Information processing device 10 Server device 11 Control unit 12 Memory unit 13 Communication unit 20 Navigation device 21 Control unit 22 Memory unit 23 Communication unit 24 Display 25 Speaker 26 Input unit 27 Interface unit 31 Camera 32 Vehicle speed sensor 33 Acceleration sensor 34 Gyro sensor 35 GNSS sensor 36 Beacon receiver 50 Traffic control center 60 Traffic light 70 Roadside device 40 Network S Driving assistance system

Claims (1)

A traffic signal information acquiring means for acquiring traffic signal information indicating a change in a traffic signal output by a traffic signal device;
An imaging information acquisition means for acquiring imaging information obtained by imaging the traffic light;
a determination means for determining whether or not there is a time difference between a manner of change of the traffic signal indicated by the acquired signal information and a manner of change of the traffic signal output by the traffic light specified based on the acquired imaging information;
An information processing device comprising:

Images