Drive assistance system and drive assistance method

Abstract

A drive assistance system includes an external server wirelessly connected to a first vehicle and a second vehicle located in a predetermined area. The drive assistance system acquires first position information and gaze information of a driver of the first vehicle, and second position information of the second vehicle, generates a traffic status map by superimposing the first position information, the gaze information, and the second position information on a digital map indicating the periphery of the predetermined area, calculates a blind area invisible from the first vehicle or the second vehicle in the traffic status map to determine a threat mode for a threat target viewed from the first vehicle or the second vehicle, and determines a notification method for the driver according to the threat mode.

Description

BACKGROUND OF THE INVENTIONField of the Invention

[0001] The present invention relates to a drive assistance system and a drive assistance method.Description of the Related Art

[0002] A drive assistance device configured to notify a driver of a vehicle of information and / or alarms according to the traffic status is known. At an intersection, in particular, a plurality of traffic participants may simultaneously exist at different positions and move in different moving directions. For this reason, the driver of a vehicle may see the traffic status changing in real time at an intersection.

[0003] Patent Document 1 (Japanese Patent Application Publication No. 2009-265832) discloses a drive assistance device configured to provide right-turn assistance with a vehicle according to the traffic status. The drive assistance device is configured to predict the status of a vehicle to make a right turn at an intersection based on the traffic status around the intersection, which is acquired via vehicle-to-vehicle communication and / or road-to-vehicle communication, to calculate a right-turn permit timing for each right-turn permit condition, and to instruct a driver of the right-turn permit timing.

[0004] A plurality of traffic participants (e.g., vehicles, two-wheel vehicles, bicycles and pedestrians) simultaneously existing around an intersection may stop or move according to traffic signals. This may incur the possibility of collision between vehicles and / or accidental contact between vehicles and pedestrians around an intersection. A variety of technologies have been developed to prevent collisions or accidental contacts between traffic participants and to secure traffic safety. For example, vehicles are equipped with in-vehicle sensors (e.g., an in-vehicle camera, a positioning device, and a millimeter wave radar) to acquire image information around vehicles, position information of vehicles, and distance information between the vehicle currently driven by a driver and its preceding vehicle or its subsequently following vehicle. In addition, engineers have developed technology to detect driver information representing a driver's gaze, a driver's head motion, and a driver's posture by use of a driver monitoring system (DMS). Moreover, engineers have developed technology to three-dimensionally measure the situation around an intersection. For example, engineers have developed the LiDAR (i.e., Laser imaging Detection and Ranging) which is configured to irradiate laser beams to an object, to analyze radio waves reflected from the object, and to sense the surrounding situation of a vehicle. By combining the LiDAR and the in-vehicle camera, it is possible to measure the shape of an object in real time with high accuracy in the order of centimeters. As objects, it is possible to assume other vehicles than the vehicle currently driven by a driver, pedestrians, and obstacles as well as any object (or any structure) such as a plurality of buildings, traffic signals and traffic signs provided at intersections, guardrails, and concrete block walls. In this connection, any obstacle and object appearing on roads will be collectively referred to as "targets".

[0005] As the surrounding situation of a vehicle based on the vehicle information acquired via V2X (i.e., Vehicle to X) communication technology such as V2V (i.e., Vehicle to Vehicle) communication and V2I (i.e., Vehicle to (roadside) Infrastructure) communication, for example, it is possible to detect the existence / nonexistence of any oncoming vehicle, the existence / nonexistence of any pedestrian, traffic status, and weather conditions. Using mobile communication technology (e.g., 4G, 5G, and WiFi), it is possible to acquire vehicle information via communication with servers such as data centers via base stations. The vehicle information would be useful to detect the existence of any traffic participant that may exist in any blind area (e.g., an area regarded as a blind spot for a driver) which cannot be detected by an in-vehicle sensor. Problems will be arisen due to any collision between vehicles at an intersection or a fork road where a plurality of roads intersect with each other, any collision between a right-turning vehicle and a straight-traveling vehicle, and / or any accidental contact between pedestrians and vehicles. As examples of vehicle information acquired via foregoing communication technology, it is possible to mention information detected by the vehicle currently driven by a driver, information detected by other vehicles, information provided from pedestrians, and information obtained from a traffic system using monitoring cameras. The vehicle information can be used to prevent any collision or accidental contact between the vehicle and other traffic participants that may exist in a blind area of the vehicle, for example, other vehicles and / or pedestrians possibly existing in an area, which are hardly viewed or recognized by a driver of the vehicle.

[0006] Japanese traffic rules shall speculate the left-hand traffic of vehicles on roads, wherein in a case of a two-lane road, a sidewalk is laid on the left side of each lane. When a vehicle makes a left turn at an intersection, a driver needs to pay attention to bicycles existing on the left side of a vehicle, pedestrians on a sidewalk, and pedestrians on a crosswalk. When a vehicle makes a right turn at an intersection, the vehicle may stop in the prescribed area of the intersection to wait till any oncoming vehicle (e.g., any straight-traveling vehicle) traveling straight in an oncoming lane goes past. In addition, a driver needs to pay attention to pedestrians existing on a sidewalk just before a crosswalk as well as pedestrians on a crosswalk traversing a right-hand road which the vehicle attempting to make a right turn will be destined to. Moreover, another vehicle that may stop and wait till a green signal is made on the right-hand road, to which the vehicle attempting to make a right turn is destined, can be recognized as an oncoming vehicle. However, a driver cannot visually recognize any target on the right-hand road, to which the vehicle attempting to make a right turn is destined, since any target may enter a blind spot of the driver. In this case, it is assumed that a reference can be made to a two-dimensional image overlooking a plurality of vehicles, pedestrians, and targets around an intersection in the air above. An actual scene of an intersection can be shown as a three-dimensional video changing every moment, wherein the driver's vision will be blocked due to the existence of roadside buildings, roadside trees, and targets, which may therefore apply limitation to a viewing range recognizable by the driver seated in the vehicle making a right turn. This may provide driver's blind spots and blind spots at intersections, in other words, any area hardly viewed by a driver due to poor visibility of roads.

[0007] The drive assistance technology such as the drive assistance device of Patent Document 1, which uses ranging sensors such as in-vehicle sensors (e.g., an in-vehicle camera and LiDAR), is designed to call an attention to the driver of a vehicle via an alert display or alarm sound or to activate control intervention such as start control of a vehicle when an oncoming vehicle enters the detection range of ranging sensors. In addition, it is possible to acquire information related to targets and other traffic participants, e.g., other vehicles, pedestrians, obstacles and traffic signs existing in blind spots of the driver of a vehicle via V2X communication technology, thus providing the information to the driver.

[0008] However, the foregoing drive assistance device has a problem such that the accuracy of drive assistance is not so high. In the situation where the vehicle currently driven by a driver makes a right turn while an oncoming vehicle is running straight in an oncoming lane, for example, the foregoing drive assistance technology is designed to provide drive assistance considering the position and the moving direction of an oncoming vehicle relative to the vehicle without clarifying which lane the oncoming vehicle is traveling in. The foregoing drive assistance technology can provide sufficient drive assistance when the driver of a vehicle making a right turn is aware of the existence of only one oncoming vehicle. However, when a plurality of traffic participants exists around an intersection, it is difficult to accurately determine whether any traffic participant, such as any oncoming vehicle or any pedestrian on a sidewalk or a crosswalk, can be assumed as a threat target (e.g., a threat target presumably incurring a risk of collision or accidental contact) with high probability or not. It is therefore necessary to provide drive assistance with high accuracy by activating an alarm at an appropriate timing based on the information of a vehicle attempting to make a right turn and the information of other traffic participants (e.g., any straight-traveling vehicles and pedestrians) according to the right-turn / straight use case, e.g., the use case in which both the vehicle attempting to make a right turn and the straight-traveling vehicle in an oncoming lane simultaneously enter an intersection.Summary of the Invention

[0009] To solve the above problem, the embodiment of the present invention aims to provide a drive assistance system and a drive assistance method which can determine a threat mode (i.e., a risk of collision or accidental contact) concerned with the possibility of collision and accidental contact between the vehicle currently driven by a driver and other traffic participants, thus executing drive assistance such as activation of an alarm to a driver at an appropriate timing according to the threat mode.

[0010] The first aspect of the present invention is a drive assistance system including a first vehicle attempting to make a turn in a predetermined area and to move in a first moving direction, a second vehicle attempting to pass through the predetermined area in a second moving direction, and an external server wirelessly connected to the first vehicle and the second vehicle. The drive assistance system includes an information acquisition unit configured to acquire first position information indicating the position of the first vehicle, gaze information indicating a gazing direction of a driver of the first vehicle, and second position information indicating the position of the second vehicle, a traffic status map generation unit configured to generate a traffic status map by superimposing the first position information and the gaze information related to the first vehicle, and the second position information related to the second vehicle on a digital map indicating the periphery of the predetermined area, a threat mode determination unit configured to calculate a first blind area invisible from the first vehicle in the traffic status map, to determine a first threat mode of a first threat target viewed from the first vehicle, to calculate a second blind area invisible from the second vehicle, and to determine a second threat mode of a second threat target viewed from the second vehicle, and a notification determination unit configured to determine a first notification method for the driver of the first vehicle according to the first threat mode and to determine a second notification method for a driver of the second vehicle according to the second threat mode.

[0011] A first threat level and a second threat level higher than the first threat level may be set to each of the first threat mode and the second threat mode, wherein the notification determination unit may determine the first notification method for the driver of the first vehicle when the threat mode determination unit determines the first threat mode at the second threat level, and the notification determination unit may determine the second notification method for the driver of the second vehicle when the threat mode determination unit determines the second threat mode at the second threat level.

[0012] The threat mode determination unit may determine the first threat mode at the second threat level when the first threat target is in the first blind area of the first vehicle, and the second threat mode at the second threat level when the second threat target is in the second blind area of the second vehicle.

[0013] The predetermined area is an intersection, wherein when the driver of the first vehicle shows an intention to make a turn at the intersection, the threat mode determination unit may determine the first threat mode for the second vehicle regarded as the first threat target viewed from the first vehicle according to the gazing direction of the driver of the first vehicle in the traffic status map.

[0014] The threat mode determination unit may determine the second threat mode for the first vehicle regarded as the second threat target viewed from the second vehicle according to the gazing direction of the driver of the second vehicle in the traffic status map.

[0015] The predetermined area is an intersection, wherein when a pedestrian having a terminal device wirelessly connected to the external server exists around the intersection, the information acquisition unit may acquire pedestrian information indicating the position and the moving direction of the pedestrian measured with the terminal device, and therefore the traffic status map generation unit may generate the traffic status map reflecting the pedestrian information. When the driver of the first vehicle shows an intention to make a turn at the intersection, the threat mode determination unit may determine the first threat mode for the pedestrian regarded as the first threat target viewed from the first vehicle according to the gazing direction of the driver of the first vehicle in the traffic status map and the pedestrian information.

[0016] The threat degree determination unit may determine a third threat mode for the first vehicle regarded as a third threat target viewed from the pedestrian according to the gazing direction of the driver of the first vehicle in the traffic status map and the pedestrian information, thus notifying the terminal device of the pedestrian of the third threat mode.

[0017] A first threat level and a second threat level higher than the first threat level may be set to each of the first threat mode, the second threat mode, and the third threat mode, wherein when the pedestrian information from the terminal device indicates that the pedestrian is in the first blind area of the first vehicle, the threat mode determination unit may determine the third threat mode at the second threat level, and the notification determination unit may determine and notify a third notification method to the terminal device.

[0018] The predetermined area is an intersection, wherein a monitoring device configured to detect the positional relationship between the first vehicle, the second vehicle, and the pedestrian from a video and to generate monitoring information is installed in the intersection. The information acquisition unit may acquire the monitoring information, the traffic status map generation unit may generate the traffic status map reflecting the monitoring information, the threat mode determination unit may determine a third threat mode for the first vehicle or the second vehicle regarded as a third threat target viewed from the pedestrian, and the monitoring device may determine a third notification method for the pedestrian according to the third threat mode.

[0019] The second aspect of the present invention is a drive assistance method including the steps of: wirelessly connecting with a first vehicle attempting to make a turn in a predetermined area and to move in a first moving direction and a second vehicle attempting to pass through the predetermined area in a second moving direction, acquiring first position information indicating the position of the first vehicle, gaze information indicating a gazing direction of the driver of the first vehicle, and second position information indicating the position of the second vehicle, generating a traffic status map by superimposing the first position information and the gaze information related to the first vehicle, and the second position information related to the second vehicle on a digital map indicating the predetermined area, calculating a first blind area invisible from the first vehicle in the traffic status map to determine a first threat mode for a first threat target viewed from the first vehicle, calculating a second blind area invisible from the second vehicle to determine a second threat mode for a second threat target viewed from the second vehicle, determining a first notification method for the driver of the first vehicle according to the first threat mode, and determining a second notification method for the driver of the second vehicle according to the second threat mode.Effect of the Invention

[0020] According to the embodiment of the present invention, it is possible to determine a threat mode (i.e. a risk of collision or accidental contact) concerned with the possibility of collision or accidental contact between the vehicle currently driven by a driver and other traffic participants, and to execute drive assistance such as activation of an alarm to the driver at an appropriate timing according to the threat mode.Brief Description of the Drawings

[0021] Fig. 1 is a schematic view showing an overview of the positional relationship among traffic participants existing around an intersection, which is applicable to a drive assistance system according to the embodiment of the present invention. Fig. 2 is a block diagram showing a schematic configuration of the drive assistance system according to the embodiment of the present invention. Fig. 3 is a block diagram showing a specific configuration of the drive assistance system according to the embodiment of the present invention. Fig. 4 is a flowchart showing a threat mode determination procedure, which is applicable to a drive assistance method according to the embodiment of the present invention. Detailed Description

[0022] A drive assistance system and a drive assistance method according to the embodiment of the present invention will be described with reference to the accompanying drawings.

[0023] The present embodiment aims to prevent a collision accident between a right-turning vehicle and a straight-traveling vehicle at an intersection. Considering the existence of other traffic participants such as other vehicles and pedestrians, the present embodiment is designed to refer to the vehicle information acquired via V2X communication and the high-precision digital map information, e.g., a three-dimensional digital map. The present embodiment is dedicated to the right-turn / straight use case in which a right-turning vehicle and a straight-traveling vehicle communicate with each other via V2X communication at an intersection, but this is not a restriction. To prevent the possibility of collision between a right-turning vehicle and a straight-traveling vehicle in the right-turn / straight use case, the present embodiment may determine an operation logic considering reference to a high-accuracy digital map, i.e., a logic for providing information or activating an alarm to a driver under a predetermined condition.

[0024] Conventionally, two-dimensional maps have been subjected to digitization, however, what drivers see in actual scenes is three-dimensional videos changing every moment. The object recognition technology of any object in the outside of vehicles using in-vehicle sensors such as in-vehicle cameras and LiDAR have made improvements in terms of the precision of digital maps using higher resolutions and higher speed (or real-time performance) applied to any means for measuring the shape of roads and the terrain around vehicles. Using three-dimensional point groups as original data of maps, it is possible to extract only the point group(s) related to the center line of lanes on roads and combine the point group(s) with white lines used to separate lanes. Three-dimensional maps, which are distinguished from digital maps conventionally installed in navigation devices, will be referred to as high-precision digital maps (or high density (HD) maps).

[0025] In the right-turn / straight use case, the vehicle attempting to make a right turn at an intersection, i.e., the right-turning vehicle needs to wait until a straight-traveling vehicle traveling straight in an oncoming lane goes past, however, not only the straight-traveling vehicle but also another right-turning vehicle may wait for an opportunity to make a right turn in the oncoming lane at an intersection. A driver of the vehicle cannot visually recognize the existence or nonexistence of a straight-traveling vehicle on the far side of the oncoming lane since the driver's sight is blocked by the vehicle body of another right-turning vehicle. In other words, a driver of the vehicle may not be able to visually recognize the straight-traveling vehicle in the oncoming lane since the driver's sight is blocked by a "blind spot" created by the presence of another right-turning vehicle in the oncoming lane. In such a traffic situation, it is possible to improve traffic safety by notifying the existence of the straight-traveling vehicle traveling in the oncoming lane, which will enter the driver's blind spot of the vehicle. Alternatively, it is possible to improve traffic safety by the driver who makes an instruction to stop the vehicle before starting the vehicle (i.e., before starting the vehicle to make a right turn at an intersection) when the straight-traveling vehicle in the oncoming lane approaches the intersection. The present embodiment is designed to perform drive assistance such as notification to the driver of the vehicle, and brake control or start control. To detect other vehicles in the oncoming lane, the present embodiment is designed to use high-precision digital maps by superimposing the position information of the vehicle and other vehicles thereon. In addition, the present embodiment is designed to determine threat modes of other traffic participants subjected to alarming or notification (e.g., oncoming vehicles and pedestrians) (i.e., threat modes indicating any risk of collision or contact between the vehicle and other traffic participants). In other words, the present embodiment is designed to prevent collisions according to threat modes by selecting a manner of notification according to threat modes before executing notification.

[0026] Next, blind spots, which are difficult to be visually recognized by the driver of the vehicle, will be described below. As blind spots of vehicles observed by the gauge of drivers, it is possible to assume physical blind spots due to the existence of pillars at four corners of vehicle bodies, driving blind spots (e.g., blind spots on left and right sides and rear sides of vehicles) which drivers might advertently neglect when intentionally focusing on some objects found during driving of vehicles, and other blind spots deviated from viewing angles of front cameras installed in vehicles.

[0027] It is difficult for drivers to directly and visually recognize physical blind spots, however, by acquiring image information viewed from other vehicles via vehicle-to-vehicle communication (or road-to-vehicle communication) with other vehicles, it is possible for drivers to recognize targets existing in physical blind spots with in-vehicle monitors. As to driving blind spots, it is possible for drivers to recognize targets existing in driving blind spots when drivers change postures of drivers' bodies to gaze side mirrors or rearview mirrors. As to other blind spots deviated from viewing angles of cameras, it is possible for drivers to recognize targets existing in other blind spots using front cameras of vehicles combined with driver monitoring systems.

[0028] In addition, it is possible to define three types of blind spots including "roadside blind spots" such as shades of other vehicles and buildings, "driver's inattentive blind spots" such as blind spots which drivers should pay attention to in right, left, and rear of vehicles and blind spots which may occur when drivers pay great attention to targets easy to attract driver's attention, and a "vehicle's blind spots" such as blind spots due to vehicles' body structures. Using a high-precision digital map overviewing the periphery of an intersection, for example, it is possible to provide the driver of the vehicle with the traffic status map indicating the traffic status around the intersection, which is produced by an external server to superimpose vehicle information (e.g., position information and movement information) obtained from the vehicle or other vehicles on the high-precision digital map. This makes it possible for the driver of the vehicle to recognize targets existing in blind spots, which are difficult to be visually recognized by the driver of the vehicle, based on the traffic status map provided from the external server.

[0029] Next, examples of the right-turn / straight use case in the traffic situation around an intersection will be described with reference to Fig. 1. Fig. 1 is a schematic view showing an overview of the positional relationship among traffic participants existing around an intersection, which is applicable to a drive assistance system 1 according to the present embodiment. At an intersection IS (Inter-Section), two roads X and Y intersect each other. Two roads X and Y are two-lane roads each including one lane on one side. Fig. 1 shows a circular range indicated by a dotted line as the intersection IS, however, this is not a restriction to the range of the intersection IS. In addition, a blind area S (e.g., Sa and Sb) occurs in the intersection IS according to the traffic situation. For the sake of explanation, one of two lanes constituting each of two roads X and Y is denoted by a reference numeral "a", while the other is denoted by a reference numeral "b". In other words, road X includes two lanes Xa and Xb, wherein lane Xb is regarded as an oncoming lane viewed from lane Xa. In addition, a plurality of crosswalks (i.e., two crosswalks for each of two roads X and Y) are laid in the intersection IS at which two lanes X and Y intersect each other. In this connection, traffic signals provided at the intersection IS are not shown here.

[0030] The present embodiment refers to a traffic environment in which two-lane roads X and Y each including one lane on one side intersect at the intersection IS as shown in Fig. 1, however, the present invention is applicable to four-lane roads each including two lanes on one side. To determine the right-turn / straight use case, for example, it is determined whether the driver of vehicle A operates a direction indicator to indicate an intention to make a right turn on road X having one lane on one side or not. The road having two lanes on one side includes a right-turn lane laid in addition to a left-turn / straight lane. For accessing the right-turn / straight use case, for example, it is possible to determine whether the driver shows an intention to make a right turn by detecting whether vehicle A moves to the right-turn lane. As described above, the present embodiment is designed to activate an operation logic dedicated to the right-turn / straight use case triggered by an event in which the driver of vehicle A shows an intention to make a right turn at the intersection IS.

[0031] As a plurality of traffic participants, Fig. 1 shows vehicles A, B, C, D and a pedestrian P existing around the intersection IS. Herein, arrows AD, BD, CD, DD represent gazing directions of drivers of vehicles A, B, C, and D. More specifically, vehicle A attempting to make a right turn in a moving direction Ta exists on one side of the intersection IS in lane Xa, while vehicle B attempting to travel straight in a moving direction Tb exists on the other side of the intersection IS in lane Xb. On one side of the intersection IS, there is building BL1 that exists away from lane Xb adjoining rightwards to lane Xa on which vehicle A exists. Thus, the gaze of the driver of vehicle A is blocked by building BL1, which causes a blind area Sa. In other words, even when the driver of vehicle A attempts to gaze rightwards to visually recognize the viewing range from a gazing direction AD1 to a gazing direction AD2, the driver's gaze is blocked by building BL1. On the other side of the intersection IS, there is building BL2 which exists away from the right side (or the left side when viewed from the driver of vehicle B) of lane Xb in which vehicle B exists. Thus, the gaze of the driver of vehicle B is blocked by building BL2, which causes a blind area Sb. In this connection, the blind areas Sa and Sb are schematically illustrated but different from actual blind spots in a traffic environment at intersections. In addition, Fig. 1 shows the blind areas Sa and Sb overlapping with each other on the side of road Y.

[0032] Vehicle A in lane Xa of road X attempts to make a right turn at the intersection IS in the moving direction Ta and to move to lane Ya of road Y. Vehicle B in lane Xb attempts to travel straight at the intersection IS in the moving direction Tb. In addition, other vehicles C and D stop in a column in lane Yb of road Y intersecting road X and wait until a traffic sign of lane Yb turns green from red. Although vehicle C is partially blocked by the blind areas Sa and Sb, the drivers of vehicles A and B can visually recognize vehicle C when the drivers pay attention to vehicle C. On the other hand, vehicle D exists in the blind areas Sa and Sb, and therefore the drivers of vehicles A and B cannot visually recognize vehicle D.

[0033] Pedestrian P, who exists on a sidewalk around building BL1 on the right side of lane Xb, is moving in a moving direction D and attempts to cross the crosswalk of road Y at the intersection IS. Fig. 1 shows pedestrian P existing in the viewing range from the gazing direction AD1 to the gazing direction AD2 when the driver of vehicle A pays attention to the right side. In other words, the driver of vehicle A in lane Xa can visually recognize pedestrian P by turning the gaze rightwards. On the other hand, the driver of vehicle B in lane Xb can visually recognize pedestrian P across the intersection IS. In addition, pedestrian P is at a position difficult to be visually recognized by the driver of vehicle C that stops in lane Yb at the stop line marked just before the crosswalk of road Y. However, it is possible for the passenger seated on the passenger seat of vehicle C, to visually recognize pedestrian P by paying attention to the left direction. In addition, it is possible for the driver of vehicle C to visually recognize pedestrian P by paying attention to the left direction.

[0034] As described above, threat targets (e.g., objects having a potential risk of collisions) for each traffic participant have different threat modes according to the positional relationship among vehicles A-D around the intersection IS, and the moving direction D of pedestrian P. As threat modes, for example, it is possible to assume urgency as to whether to perform notification to the driver of the vehicle and / or control intervention of the vehicle. The present embodiment is designed to store a traffic status map, which is created by superimposing the position information of vehicles A and B and the drivers' gaze information on the high-precision digital map, in the external server and to determine the threat mode for each traffic participant by executing calculations according to a predetermined logic.

[0035] The present embodiment sets three threat levels with respect to threat targets serving as other traffic participants viewed from vehicles (e.g., vehicle B and pedestrian P viewed from vehicle A) according to the position information of traffic participants (e.g., vehicles A and B) and the gaze information of the drivers of vehicles A and B. As to the position information of traffic participants, it is possible to grasp the relative positional relationship among vehicles at the intersection IS by storing the vehicle information in the external server via V2X communication. The driver's gaze information can be measured using the driver monitoring system (DMS) such that the vehicle information including the gaze information can be transmitted to the external server, and therefore it is possible to grasp the gazing directions of the drivers of vehicles A and B, which are facing each other at the intersection IS, in the traffic status map created by superimposing the gaze information and the position information of traffic participants on the high-precision digital map

[0036] Threat level 1: the driver's gaze is directed to the threat target, thus preventing a collision (or an accidental contact) with ease.

[0037] Threat level 2: a collision (or an accidental contact) can be prevented if the driver changed the gazing direction to visually recognize the threat target.

[0038] Threat level 3: the threat target exists in the blind area S, and therefore the driver cannot visually recognize the threat target although the driver changes the gazing direction.

[0039] The above-described threat levels are not fixed values and change every moment according to the traffic status at the intersection IS. The present embodiment is designed to determine the threat level of the threat target and to provide information to the driver and / or to notify an alarm according to the threat level. When the present embodiment determines the threat mode using the gazing direction AD of the driver of vehicle A (i.e., a right-turning vehicle) and the gazing direction BD of the driver of vehicle B (i.e., a straight-traveling vehicle), for example, the present embodiment may provide the information related to vehicle B to the driver of vehicle A and / or notify an alarm to the driver of vehicle A when the threat mode is at threat level 2 or threat level 3.

[0040] Due to a clear view secured through the intersection IS, the threat mode of vehicle B (i.e., a straight-traveling vehicle) viewed from vehicle A (i.e., a right-turning vehicle) may be determined at threat level 1, while the threat mode of vehicle A (i.e., a right-turning vehicle) viewed from vehicle B (i.e., a straight-traveling vehicle) may be determined at threat level 1, however, which would achieve a minor effect (e.g., a collision prevention effect) even when an alarm is set off to the drivers of vehicles A and B. For this reason, the present embodiment is designed to set off an alarm to the driver of a vehicle encountering a threat target presumably having a relatively high threat level, i.e., a threat target whose threat mode is presumably determined at threat level 2 or threat level 3 higher than threat level 1. When the driver becomes aware of the existence of the threat target at an early timing to perform a collision preventive operation, it is possible to reduce the risk of collision. The collision preventive operation can be realized by driver's operations for decelerating, stopping, and steering the vehicle.

[0041] The threat mode determination method of the present embodiment will be described with reference to Fig. 1. It is possible for the driver of vehicle A to prevent a collision with vehicle B, which can be visually recognized from vehicle A, and therefore vehicle B is determined to have the threat mode at threat level 1. Concerning vehicle C viewed from vehicle A, it is possible for the driver of vehicle A to prevent a potential collision with vehicle C when the driver of vehicle A attempting to make a right turn can visually recognize vehicle C by changing the gazing direction rightwards. Thus, vehicle C, which is viewed by the driver of vehicle A, is determined to have the threat mode at threat level 2. Concerning pedestrian P viewed from vehicle A, it is possible to prevent a potential collision (or a contact) with pedestrian P when the driver of vehicle A changes the gazing direction rightwards to visually recognize pedestrian P, and therefore pedestrian P is determined to have the threat mode at threat level 2. In addition, the threat mode of pedestrian P will be reduced from threat level 2 to threat level 1 when the driver of vehicle A can visually recognize pedestrian P by changing the gazing direction AD rightwards and paying attention to a viewing range from the gazing direction AD1 to the gazing direction AD2. Vehicle D exists in the blind area Sa viewed from vehicle A. If the driver of vehicle A tried to visually recognize the right direction, the driver of vehicle A can visually recognize pedestrian P, however, the driver of vehicle A cannot visually recognize vehicle D, which completely enters the blind area Sa. Thus, vehicle D viewed from vehicle A is determined to have the threat mode at threat level 3.

[0042] On the other hand, when the driver of vehicle B pays close attention to the front side thereof, the driver of vehicle B can visually recognize vehicle A and pedestrian P through the intersection IS. Thus, vehicle A and pedestrian P serving as threat targets viewed from the driver of vehicle B are both determined to have the threat mode at threat level 1. Concerning vehicle C partially blocked by the blind area Sb, the driver of vehicle B can visually recognize vehicle C by changing the gazing direction BD and gazing the left direction through the intersection IS. Thus, vehicle C viewed from vehicle B is determined to have the threat mode at threat level 2. Concerning vehicle D completely entering the blind area Sb, the driver of vehicle B cannot visually recognize vehicle D located in the rear side of vehicle C even when the driver of vehicle B changes the gazing direction BD. Thus, vehicle D viewed from vehicle B is determined to have the threat mode at threat level 3.

[0043] As described above, vehicle D viewed from vehicles A and B is determined to have the threat mode at threat level 3, and therefore an alarm is notified to vehicles A and B or the information indicating that vehicle D exists behind vehicle C is provided to vehicles A and B as necessary. Considering that vehicle D is wirelessly connected to the external server, it is possible to assume that the vehicle information of vehicle D may be reflected in the high-precision digital map. In this case, the drivers of vehicles A and B cannot directly gaze at vehicle D; however, if the drivers of vehicles A and B were each provided with the information based on the high-precision digital map, the drivers of vehicles A and B can confirm that vehicle D exists behind vehicle C.

[0044] The traffic status map of the intersection IS (or a digital map indicating the traffic status of the intersection IS), which is created by superimposing the vehicle information on the high-precision digital map stored in the external server, will be sequentially updated according to variations of the position or the moving direction of any traffic participant, and therefore the determination result about the threat level related to any threat target may be continuously updated in a short period of time. Thus, traffic participants can sequentially download (or browse) the traffic status of a predetermined region, for example, by making an inquiry upon designating the predetermined region (e.g., the periphery of the intersection IS) in the high-precision digital map. This makes it possible for traffic participants (e.g., vehicle A) to prevent a potential collision with any threat target by confirming the status of other traffic participant (e.g., vehicles B and C, and pedestrian P) in real time. In this manner, the present embodiment can implement drive assistance to smoothly execute the traveling of vehicles A and B by paying attention to pedestrian P in the right-turn / straight use case at the intersection IS.

[0045] Fig. 2 is a block diagram showing an example of the configuration of the drive assistance system 1 according to the present embodiment. In the drive assistance system 1, vehicle 10 (e.g., vehicle A) and other traffic participants 20 are wirelessly connected to a data server 30 via V2X communication. As examples of other traffic participants 20, for example, it is possible to mention other vehicles B and C, a terminal device having a communication function carried by pedestrian P, and a monitoring camera installed in the intersection IS. It is possible to acquire images indicating the traffic status of the intersection IS using the monitoring camera. The monitoring camera can specify the position of vehicles A, B, and C and / or the position of pedestrian P (or the terminal device possessed by pedestrian P), which may approach the intersection IS, by way of image processing or image analysis. The data server 30 is an external server connected to the Internet, which may be a cloud server located at a remote place, a roadside device or an edge server installed in the vicinity of road networks. The data server 30 is configured to store a high-precision digital map M. The present embodiment focuses on a predetermined region around the intersection IS within the entire digital data of the high-precision digital map M.

[0046] Vehicle 10 and other traffic participants 20 (in particular, other vehicles) are each equipped with a GPS (Global Positioning System) to acquire the position information of navigation. The drive assistance system 1 according to the present embodiment includes a GNSS (Global Navigation Satellite System) 40 to acquire detailed position information in view of communication satellites in real time. Both vehicle 10 and other traffic participants 20 can make an inquiry to the GNSS 40 to acquire detailed position information.

[0047] The data server 30 cooperates with a plurality of road cameras 50 installed in the periphery of roads. In this connection, the road cameras 50 may include the monitoring camera installed in the intersection IS. Thus, the road cameras 50 can shoot videos about a plurality of vehicles traveling on roads in real time, thus transmitting videos as traffic information to the data server 30. The data server 30 receives videos from road cameras 50 and reflects the traffic status (e.g., traveling conditions of vehicles) changing every moment in the high-precision digital map M.

[0048] Next, the function of the drive assistance system 1 will be described below. Vehicle 10 (e.g., vehicle A) makes an inquiry to GNSS 40 to acquire first position information a. Other traffic participants 20 (e.g., vehicle B) make an inquiry to GNSS 40 to acquire second position information b. On the other hand, the data server 30 acquires traffic information c (i.e., the traffic status of the intersection IS in which vehicles A-D and pedestrian P exist closely) indicating the position and the moving direction of vehicles and pedestrians based on videos shot by road cameras 50. In this connection, the first position information a, the second position information b, and the traffic information c can be acquired from external sensors, which may constitute peripheral technical elements in the periphery of vehicle 10, other traffic participants 20, and the data server 30 serving as the core of the drive assistance system 1.

[0049] Vehicle 10 generates the first position information a, the operating state of a direction indicator, the driver's gaze information and the direction of the driver's head (i.e., the driver information detected by the driver monitoring system), and first vehicle information d including the vehicle body information and the driving status of vehicle 10, which are transmitted to the data server 30. The present embodiment deals with the operating state of a direction indicator as a directional instruction indicating the driver's intention to make a straight travel, a right turn, or a left turn. Fig. 1 shows that the driver of vehicle A operates the direction indicator to show an intention to make a right turn. In two-lane roads X and Y shown in Fig. 1, a driver's intension which the driver may arbitrarily determine with respect to the directional instruction can be determined according to the presence or absence of a driver's operation of the direction indicator, whereas in four-lane roads, it is possible to determine a driver's intention according to the movement of a vehicle toward a right-turn lane as well. In a similar manner, other traffic participants 20 may generate the second position information b, the operating state of a direction indicator, the driver's gaze information, and the direction of the driver's head (i.e., the driver information detected by the driver monitoring system), and second vehicle information e including the vehicle body information and the driving status of other traffic participants 20 (e.g., other vehicles), which are transmitted to the data server 30.

[0050] When pedestrian P acts as one of the other traffic participants 20, the pedestrian P can visually recognize a traffic signal at the intersection IS as well as vehicles A, B, and C. The present embodiment exemplifies a smartphone as a terminal device, i.e., a means for establishing a wireless connection between pedestrian P and the drive assistance system 1. In this case, it is possible to acquire the position of the terminal device of pedestrian P as the second position information b acquired from GNSS 40. Alternatively, it is possible to use the position information, which the terminal device of pedestrian P acquires in cooperation with other satellite communication systems. In addition, the second vehicle information e may include the pedestrian information further including the position information of the terminal device and the moving direction of pedestrian P (or direction of the head of pedestrian P) detected by the terminal device.

[0051] The data server 30 is configured to store, as the high-precision digital map M, a map of road networks in a predetermined territory in Japan (e.g., the Kanto area of Japan) and a three-dimensional map indicating positions and heights of buildings. The data server 30 is configured to update the high-precision digital map M according to the traffic information c obtained from road cameras 50. In addition, the data server 30 is configured to acquire the first vehicle information d from vehicle 10 and the second vehicle information e from other traffic participants 20. The data server 30 is configured to generate a traffic status map by reflecting the positions of vehicles A-D at the intersection IS and the position of pedestrian P in the high-precision digital map M in real time according to a predetermined algorithm.

[0052] Thereafter, the data server 30 determines the threat level of a threat target according to a predetermined operation logic in view of the traffic status map. Although the present embodiment can set the threat mode at threat levels 1 to 3, the threat level may be varied with respect to each threat target viewed from any traffic participant, and therefore the threat level will be updated according to any change in the driver's gazing direction or any change in the traffic status. Assuming vehicle 10 as vehicle A, vehicle B and pedestrian P reflected in the driver's field of vision are regarded as threat targets while vehicle C would be regarded as another threat target viewed from the vehicle making a right turn. Assuming vehicle B as other traffic participants 20, vehicle A and pedestrian P reflected in the driver's field of vision are regarded as threat targets while vehicle C would be regarded as another threat target due to the status of a traffic signal at the intersection IS. Thus, the data server 30 is configured to determine the threat level for each traffic participant, to notify vehicle 10 of a first threat level f related to a first threat target, and to notify other traffic participants 20 of a second threat level g related to a second threat target. In this connection, the first threat level f and the second threat level g can be set to the same threat level or different threat levels.

[0053] Next, a specific configuration of the drive assistance system 1 according to the present embodiment will be described with reference to the block diagram of Fig. 3. Fig. 3 shows another vehicle 210 (e.g., vehicle B), a terminal device 220 held by pedestrian P, and a monitoring device 230 installed in the intersection IS as other traffic participants 20 in addition to vehicle 100 (e.g., vehicle A) corresponding to vehicle 10 shown in Fig. 2. In addition, there is an external server 300 corresponding to the data server 30 shown on Fig. 2. Vehicle 100, the other vehicle 210, the terminal device 220, and the monitoring device 230 are wirelessly connected to the external server 300, while vehicle 100 and the other vehicle 210 can mutually exchange information via V2V communication.

[0054] Vehicle 100 includes sensors 101 (e.g., an in-vehicle camera, a LiDAR, and a driver monitoring system), a vehicle information generation unit 102, a vehicle information transmission unit 103, a notification determination unit 104, and a notification unit 105. The other vehicle 210 has the same configuration as the configuration of vehicle 100. The vehicle information generation unit 102 is configured to generate the first vehicle information based on the first position information from GNSS 40, and the driver information (e.g., the driver's gaze information) detected by sensors 101. The vehicle information transmission unit 103 of vehicle 100 is configured to transmit the first vehicle information to the external server 300. In a similar manner, the other vehicle 210 is configured to generate the second vehicle information based on the second position information from GNSS 40 and the driver information, and to transmit the second vehicle information to the external server 300. In this connection, the external server 300 has already stored the high-precision digital map M.

[0055] The terminal device 220 held by pedestrian P can measure the position thereof (hereinafter, referred to as third position information) by way of the GPS function thereof. In addition, the terminal device 220 can detect the behavior of pedestrian P. For example, the terminal device 220 can detect the direction of the head of pedestrian P or the moving direction of pedestrian P via face authentication of pedestrian P. Thus, the terminal device 220 is configured to generate the pedestrian information based on the third position information of the terminal device 220 and the behavior of pedestrian P in place of the first vehicle information and the second vehicle information, thus transmitting the pedestrian information to the external server 300.

[0056] The monitoring device 230 is installed in the intersection IS together with traffic signals and equipped with a monitoring camera 231 and a speaker 232. The position of the monitoring device 230 (hereinafter, referred to as fourth position information) is set in advance, wherein the monitoring device 230 is configured to analyze images reflecting vehicle 100, the other vehicle 210, and pedestrian P, which are captured by the monitoring camera 231, thus detecting the positions thereof. In other words, the monitoring device 230 is configured to generate the monitoring information indicating the current positions of vehicle 100, the other vehicle 210, and pedestrian P at the intersection IS, thus transmitting the monitoring information to the external server 300. In this connection, the speaker 232 can transmit a predetermined message in sound to a plurality of traffic participants existing around the intersection IS. If the pedestrian P did not hold the terminal device 220, it is possible to convert an alarm from the external server 300 into sound and to convey the alarm to pedestrian P by way of the speaker 232 of the monitoring device 230.

[0057] The external server 300 includes an information acquisition unit 301, a traffic status map generation unit 302, a threat mode determination unit 303, and a threat mode transmission unit 304. The information acquisition unit 301 is configured to acquire traffic information from road cameras 50 shown in Fig. 2. In addition, the information acquisition unit 301 is configured to acquire the first vehicle information from vehicle 100, the second vehicle information from the other vehicle 210, the pedestrian information from the terminal device 220 held by pedestrian P, and the monitoring information from the monitoring device 230. The traffic status map generation unit 302 is configured to reflect the first vehicle information, the second vehicle information, the pedestrian information, and the monitoring information in the high-precision digital map M. Thus, the traffic status map generation unit 302 is configured to generate the traffic status map, which is created by projecting the position of the terminal device 220 and the position of the monitoring device 230 in addition to the positional relationship of vehicle 100 and the other vehicle 210 onto a three-dimensional map in a predetermined area such as the intersection IS. The threat mode determination unit 303 is configured to determine threat modes for threat targets viewed from a predetermined traffic participant according to a predetermined determination logic responsive to the positional relationship among traffic participants (e.g., vehicle 100, the other vehicle 210, and the terminal device 220 held by pedestrian P) on the traffic status map. The threat mode transmission unit 304 is configured to transmit threat modes to vehicle 100, the other vehicle 210, the terminal device 220, and the monitoring device 230 respectively. In this connection, the monitoring device 230 does not have any threat target, whereas if the monitoring device 230 detected pedestrian P, threat modes related to threat targets viewed from pedestrian P will be transmitted to the monitoring device 230 from the external server 300.

[0058] In vehicle 100, the notification determination unit 104 is configured to determine notification methods according to threat modes notified thereto from the external server 300. The notification unit 105 activates speakers in vehicle 100 according to notification methods to notify the driver of alarms using predetermined sound. In this case, it is possible to change the volume of sound according to each threat mode. Alternatively, it is possible to display an alarm such as a predetermined image or a predetermined message on a navigation device (or a display of vehicle 100 serving as the notification unit 105).

[0059] In this connection, the notification determination unit 104 configured to determine notification methods for vehicle 100 is installed inside vehicle 100; however, it is possible to provide the external server 300 with the function of the notification determination unit 104. In a similar manner, it is possible to provide the external server 300 with the function of determining notification methods for the other vehicle 210. In this case, the external server 300 is configured to determine the notification method for vehicle 100 (or the other vehicle 210) based on the threat mode determined by the threat mode determination unit 303. In addition, the external server 300 includes the threat mode transmission unit 304 which functions as a notification method transmission unit configured to transmit to the notification unit 105 of vehicle 100 the notification method determined as described above.

[0060] Fig. 3 shows that the external server 300 implements a process of generating the traffic status map based on the high-precision digital map M and a threat mode determination process of determining threat modes; however, these functions can be distributed separately to the external server 300 and in-vehicle computers mounted on vehicle 100 and the other vehicle 210. The high-precision digital map M requiring a large amount of information should be implemented on the external server 300. In addition, the process of generating the traffic status map requiring high computation capability should be implemented on the external server 300. However, it is possible to implement on in-vehicle computers a process of determining threat modes of other traffic participants considering driver's blind spots. For example, an in-vehicle computer may make an inquiry to the external server 300 to read the traffic status map around an intersection, thus grasping the positional relationship between blind areas viewed from the driver of a vehicle and other traffic participants with a simple diagram (e.g., a two-dimensional diagram as shown in Fig. 1). In other words, an in-vehicle computer can determine threat modes of threat targets with relatively small computation capability if an in-vehicle computer could acquire a simple version (or a small-scale version focusing on the intersection IS) of the traffic status map having a relatively small amount of information from the external server 300.

[0061] Next, the threat mode determination method implemented by the data server 30 (or the threat mode determination unit 303 of the external server 300) will be described with reference to the flowchart of Fig. 4. The data server 30 (or the external server 300) includes a processor and a storage device configured to store programs related to the threat mode determination process. As the processor, it is possible to use a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). The processor may execute the threat mode determination process to calculate threat modes according to multiple conditions respectively.

[0062] When a plurality of traffic participants may serve as a plurality of threat targets, it is necessary to calculate threat modes for each traffic participant by executing control flows in parallel for each traffic participant. Upon focusing on vehicles A and B (i.e., vehicle 100 and the other vehicle 210) and pedestrian P (i.e., the terminal device 220) at the intersection IS in Fig. 1, it is necessary to calculate six combinations of threat modes as follows. (1) Threat Mode for vehicle B viewed from vehicle A (2) Threat Mode for pedestrian P viewed from vehicle A (3) Threat Mode for vehicle A viewed from vehicle B (4) Threat Mode for pedestrian P viewed from vehicle B (5) Threat Mode for vehicle A viewed from pedestrian P (6) Threat Mode for vehicle B viewed from pedestrian P

[0063] The flowchart of Fig. 4 includes an input process IN, step S10, and step S20 describing multiple conditions. The flowchart of Fig. 4 is written upon focusing on the data server 30 in the drive assistance system 1 shown in Fig. 2, wherein other traffic participants 20 viewed from the driver of vehicle 10 are assigned to individual threat modes at threat level 1 to threat level 3. The other traffic participant 20, which does not exist in driver's blind spots, is determined to have the threat mode at threat level 1 if the driver visually recognized the other traffic participant 20; however, the other traffic participant 20 is determined to have the threat mode at threat level 2 if the driver did not visually recognize the other traffic participant 20. In addition, the other traffic participant 20, which exists in driver's blind spots, is determined to have the threat mode at threat level 3. Herein, the present embodiment sets the inequality of "threat level 1 < threat level 2 < threat level 3"; however, this is not a restriction.

[0064] First, the data server 30 inputs various kinds of sensing data (IN). As sensing data, the data server 30 inputs the first position information a of vehicle 10, the second position information b of the other traffic participant 20, the gazing direction and the direction of the head of the driver of vehicle 10 (or the other vehicle regarded as the other traffic participant 20).

[0065] When the other traffic participant 20 regarded as a threat target of vehicle 10 exists in the blind area S, it is determined that the other traffic participant 20 has the threat mode at threat level 3 (step S10). When the driver of vehicle 10 turns the gaze to the other traffic participant 20 in a case where the other traffic participant 20 regarded as a threat target of vehicle 10 does not exist in the blind area S, it is determined that the other traffic participant 20 has the threat mode at threat level 1 (step S20, YES). On the other hand, when the driver of vehicle 10 does not turn the gaze to the other traffic participant 20, it is determined that the other traffic participant 20 has the threat mode at threat level 2 (step S20, NO). In this manner, even if the other traffic participant 20 did not exist in the blind area S, the present embodiment calculates threat levels differently according to the gazing direction of the driver of vehicle 10.

[0066] In Fig. 1, we will study the positional relationship among vehicles A and B, and pedestrian P. Just before the intersection IS, the drivers of vehicles A and B turn the gazing directions AD and BD to the straight directions. Since vehicle B is visually recognized in view of the driver of vehicle A, it is determined that vehicle B has the threat mode at threat level 1 (step S20, YES). Since the gazing direction AD of the driver of vehicle A differs from the position of pedestrian P, it is determined that pedestrian P has the threat mode at threat level 2 (step S20, NO). However, if the driver of vehicle A visually recognized pedestrian P, it is determined that pedestrian P has the threat mode at threat level 1 (step S20, YES). In this case, when vehicle A attempts to make a right turn in the moving direction Ta when approaching a crosswalk, it is likely that vehicle A may contact or collide with pedestrian P who is walking on the crosswalk according to the state of a traffic signal at the intersection IS. Thus, vehicle A should notify the driver of a strong alarm or perform control intervention such as forced braking to cope with the threat target which is determined to have the threat mode at threat level 3.

[0067] On the other hand, although vehicle A and pedestrian P can be regarded as threat targets viewed from vehicle B, vehicle A attempting to make a right turn and pedestrian P can be visually recognized in the viewing range related to the gazing direction BD of the driver of vehicle B, and therefore it is determined that vehicle A and pedestrian P viewed from vehicle B have the threat mode at threat level 1 (see step S10 → step S20). On the other hand, vehicle C that waits until a traffic signal turns green from red in lane Yb of road Y would be regarded as a threat target viewed from vehicle B according to the state of the traffic signal. Since vehicle C viewed from vehicle B is not in the blind area Sb, it is determined that vehicle C has the threat mode at threat level 1 (step S20). Considering that vehicle B may take time to pass through the intersection IS due to the congested state of the intersection IS, it is likely that a traffic signal installed along road X will be changed from green to red. In this case, the traffic signal installed along road Y turns to green from red, it is likely that vehicle C waiting in lane Yb may start to move forwards. For this reason, it is possible to assume that vehicle C serving as the threat target of vehicle B may be changed in the threat level thereof from threat level 1 to threat level 2 or threat level 3.

[0068] In addition, vehicles A, B, C can be regarded as threat targets viewed from pedestrian P. Pedestrian P who is walking in the moving direction D across a crosswalk of road Y can visually recognize vehicle B traveling straight along lane Xb, and therefore it is determined that vehicle B has the threat mode at threat level 1 (step S20). As to vehicle A attempting to make a right turn at the intersection IS, it is likely that pedestrian P may not notice the existence of vehicle A until vehicle A approaches a crosswalk which pedestrian P is currently walking across. Thus, it is determined that vehicle A viewed from pedestrian P has the threat mode at threat level 2 or threat level 3. Normally, the driver of vehicle A has an obligation to pay attention to pedestrians walking on crosswalks, and therefore vehicle A shall be notified of an alarm indicating the existence of pedestrian P.

[0069] As shown in Fig. 3, when pedestrian P has the terminal device 220, the external server 300 may transmit the threat mode to the terminal device 220, which is thus notified of an alarm. When pedestrian P does not have the terminal device 220, the monitoring device 230 shall detect the proximate condition between vehicle A, which makes a right turn at an intersection to approach a crosswalk on road Y, and pedestrian P who is moving along the crosswalk, and therefore the external server 300 notifies the monitoring device 230 of the threat mode based on the monitoring information. When vehicle A and pedestrian P are mutually regarded as threat targets at threat level 2 or threat level 3 when viewed by the monitoring device 230, vehicle A is notified of an alarm while an alert in sound is notified to pedestrian P via the speaker 232 of the monitoring device 230.

[0070] Next, modifications and effects of the drive assistance system and the drive assistance method (particularly, a threat mode determination method and a notification method of an alarm or the like) according to the present invention will be described below. The following descriptions will be written with reference to the block diagram of Fig. 3; however, the functionality shown in Fig. 3 is illustrative and not restrictive. In this connection, the function of the notification determination unit 104 mounted on the vehicle 100 can be mounted on the external server 300.

[0071] The drive assistance system 1 includes vehicle 100 attempting to make a turn in a predetermined area such as an intersection and to move in a first moving direction, the other vehicle 210 attempting to pass through the predetermined area in a second moving direction, and the external server 300 wirelessly connected to vehicle 100 and the other vehicle 210. In the drive assistance system 1, a traffic status map is generated by superimposing the first position information of vehicle 100, the gaze information of the driver, and the second position information of the other vehicle 210 on a digital map indicating the periphery of the predetermined area. A first blind area invisible from vehicle 100 in the traffic status map is calculated to determine a first threat mode for a first threat target viewed from vehicle 100, while a second blind area invisible from the other vehicle 210 is calculated to determine a second threat mode for a second threat target viewed from the other vehicle 210. Thereafter, the first notification method is determined for the driver of vehicle 100 according to the first threat mode, while the second notification method is determined for the driver of the other vehicle 210 according to the second threat mode.

[0072] In this manner, it is possible to implement an appropriate notification method to the driver of vehicle 100 at an appropriate timing according to a threat mode for a threat target determined in view of the blind spot viewed from the driver of vehicle 100. This makes it possible to prevent the risk of collision (or the risk of contact) between vehicle 100 and other traffic participants such as the other vehicle 210.

[0073] A first threat level and a second threat level higher than the first threat level can be set to the first threat mode for the first threat target of vehicle 100 and the second threat mode for the second threat target of the other vehicle 210. In this case, upon determining the first threat mode or the second threat mode at the second threat level, it is possible to determine the notification method for the driver of vehicle 100 or the other vehicle 210. For example, it is possible to determine the first threat mode at the second threat level when the first threat target of vehicle 100 enters the first blind area, while it is possible to determine the second threat mode at the second threat level when the second threat target of the other vehicle 210 enters the second blind area. Thus, it is possible to prevent the situation in which the driver having an uneasy feeling fails to pay attention to a significant alarm since the driver of vehicle 100 or the other vehicle 210 is normally notified of an alarm irrespective of highness or lowness of the first threat mode of the first threat target or the second threat mode of the second threat target.

[0074] When the predetermined area is an intersection, it is assumed that vehicle 100 attempts to make a right turn at the intersection, while the other vehicle 210 travels straight in an oncoming lane to pass through the intersection. In this case, when the driver of vehicle 100 shows an intention to make a right turn at the intersection, it is possible to determine the first threat mode for the other vehicle 210 regarded as the first threat target according to the gazing direction of the driver of vehicle 100 in the traffic status map. The determination process of the first threat mode of the other vehicle 210 to be regarded as the first threat target in view of the traffic status map bears a high computation load. Upon determining the first threat mode by executing a predetermined operation logic when the driver of vehicle 100 shows an intention to make a right turn at the intersection, it is possible to prevent the external server 300 from normally bearing a high computation load.

[0075] In the above, it is possible to determine the second threat mode for vehicle 100 regarded as the second threat target according to the gazing direction of the driver of the other vehicle 210 in the traffic status map.

[0076] When the predetermined area is an intersection, it is possible to assume that a pedestrian attempts to cross a crosswalk around the intersection while the terminal device 220 held by the pedestrian is wirelessly connected to the external server 300. In this case, the drive assistance system 1 may reflect the pedestrian information indicating the position and the moving direction of the pedestrian detected by the terminal device 220 in the traffic status map. In addition, when the driver of a vehicle shows an intention to make a right turn at the intersection, it is possible to determine the first threat mode for the pedestrian to be regarded as the first threat target according to the gazing direction of the driver of vehicle 100 and the moving or gazing direction of the pedestrian in the traffic status map. Upon determining the first threat mode by executing a predetermined operation logic when the driver of vehicle 100 shows an intention to make a right turn at the intersection, it is possible to prevent the external server 300 from normally bearing a high computation load.

[0077] In the above, upon determining vehicle 100 or the other vehicle 210 viewed from the pedestrian as a third threat target, it is possible to determine a third threat mode according to the moving or gazing direction of the pedestrian in the traffic status map, thus notifying the terminal device 220 of the pedestrian of the third threat mode. In this connection, it is possible to determine the moving direction of the pedestrian using a position / orientation sensor built in the terminal device such as a smartphone, or a traffic monitoring camera installed near an intersection. In a similar manner, it is possible to determine the gazing direction (or the direction of the head) of the pedestrian using a traffic monitoring camera installed near an intersection.

[0078] In the above, when the monitoring device 230 is installed near intersection, it is possible to determine the positional relationship among vehicle 100, the other vehicle 210, and the pedestrian based on videos shot by the monitoring camera 231 of the monitoring device 230. The monitoring device 230 generates the monitoring information indicating the traffic status in the periphery of the intersection. The monitoring information is reflected in the traffic status map. Even when the pedestrian does not hold the terminal device 220, for example, it is possible to track the position of the pedestrian at an intersection via the monitoring device 230. When the pedestrian is walking on a crosswalk, vehicle 100 or the other vehicle 210 would be regarded as a third threat target viewed from the pedestrian, indicating the potential occurrence of a contact / collision risk. In this case, it is possible to determine the third threat mode for the third threat target viewed from the pedestrian based on the monitoring information from the monitoring device 230, thus notifying the pedestrian of an alarm using the speaker 232 mounted on the monitoring device 230. Thus, it is possible to secure safety of the pedestrian at an intersection even if the pedestrian did not hold the terminal device 220.

[0079] By notifying not only vehicle 100 and the other vehicle 210 but also other traffic participants such as pedestrians of threat modes determined in view of the traffic status map, it is possible to encourage vehicle 100, the other vehicle 210, and pedestrians to perform preventive measures to prevent collision risks. When other traffic participants such as pedestrians exist in the blind spots of the driver of vehicle 100 and the driver of the other vehicle 210, it is possible to notify the drivers of the potential occurrence of collision risks, thus effectively preventing collision risks.

[0080] Although the present invention has been described in conjunction with various embodiments, the embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in other forms accompanied by various omissions, replacements, and changes within a range not deviating from the gist of the invention. These embodiments and modifications are therefore included in the scope and the gist of the invention; hence, these embodiments shall be included in the invention as defined in claims and equivalents thereof.Reference Signs List

[0081] 10 vehicle 20 other traffic participant 30 data server 40 GNSS 50 road camera 100 vehicle 101 sensors 102 vehicle information generation unit 103 vehicle information transmission unit 104 notification determination unit 105 notification unit 210 other vehicle 220 terminal device 230 monitoring device 300 external server 301 information acquisition unit 302 traffic status map generation unit 303 threat mode determination unit 304 threat mode transmission unit A, B, C, D vehicle BL1, BL2 building IS intersection M high-precision digital map P pedestrian S, Sa, Sb blind area X, Y road Xa, Xb, Ya, Yb lane

Claims

1. A drive assistance system including a first vehicle attempting to make a turn in a predetermined area and to move in a first moving direction, a second vehicle attempting to pass through the predetermined area in a second moving direction, and an external server wirelessly connected to the first vehicle and the second vehicle, the drive assistance system, comprising: an information acquisition unit configured to acquire first position information indicating a position of the first vehicle, gaze information indicating a gazing direction of a driver of the first vehicle, and second position information indicating a position of the second vehicle; a traffic status map generation unit configured to generate a traffic status map by superimposing the first position information and the gaze information related to the first vehicle, and the second position information related to the second vehicle on a digital map indicating a periphery of the predetermined area; a threat mode determination unit configured to calculate a first blind area invisible from the first vehicle in the traffic status map, to determine a first threat mode of a first threat target viewed from the first vehicle, to calculate a second blind area invisible from the second vehicle, and to determine a second threat mode of a second threat target viewed from the second vehicle; and a notification determination unit configured to determine a first notification method for the driver of the first vehicle according to the first threat mode and to determine a second notification method for a driver of the second vehicle according to the second threat mode.

2. The drive assistance system according to claim 1, wherein a first threat level and a second threat level higher than the first threat level are set to each of the first threat mode and the second threat mode, the notification determination unit is configured to determine the first notification method for the driver of the first vehicle when the threat mode determination unit determines the first threat mode at the second threat level, and the notification determination unit is configured to determine the second notification method for the driver of the second vehicle when the threat mode determination unit determines the second threat mode at the second threat level.

3. The drive assistance system according to claim 2, wherein the threat mode determination unit is configured to determine the first threat mode at the second threat level when the first threat target is in the first blind area of the first vehicle and to determine the second threat mode at the second threat level when the second threat target is in the second blind area of the second vehicle.

4. The drive assistance system according to claim 1, wherein the predetermined area is an intersection, and wherein when the driver of the first vehicle shows an intention to make a turn at the intersection, the threat mode determination unit is configured to determine the first threat mode for the second vehicle regarded as the first threat target viewed from the first vehicle according to the gazing direction of the driver of the first vehicle in the traffic status map.

5. The drive assistance system according to claim 4, wherein the threat mode determination unit is configured to determine the second threat mode for the first vehicle regarded as the second threat target viewed from the second vehicle according to a gazing direction of the driver of the second vehicle in the traffic status map.

6. The drive assistance system according to claim 1, wherein the predetermined area is an intersection, and wherein when a pedestrian having a terminal device wirelessly connected to the external server exists around the intersection, the information acquisition unit is configured to acquire pedestrian information indicating a position and a moving direction of the pedestrian measured with the terminal device, the traffic status map generation unit is configured to generate the traffic status map reflecting the pedestrian information, and wherein when the driver of the first vehicle shows an intention to make a turn at the intersection, the threat mode determination unit is configured to determine the first threat mode for the pedestrian regarded as the first threat target viewed from the first vehicle according to the gazing direction of the driver of the first vehicle in the traffic status map and the pedestrian information.

7. The drive assistance system according to claim 6, wherein the threat mode determination unit is configured to determine a third threat mode for the first vehicle regarded as a third threat target viewed from the pedestrian according to the gazing direction of the driver of the first vehicle in the traffic status map and the pedestrian information, thus notifying the terminal device of the pedestrian of the third threat mode.

8. The drive assistance system according to claim 7, wherein a first threat level and a second threat level higher than the first threat level are set to each of the first threat mode, the second threat mode, and the third threat mode, and wherein when the pedestrian information from the terminal device indicates that the pedestrian is in the first blind area of the first vehicle, the threat mode determination unit is configured to determine the third threat mode at the second threat level, and the notification determination unit is configured to determine and notify a third notification method to the terminal device.

9. The drive assistance system according to claim 1, wherein the predetermined area is an intersection while a monitoring device configured to determine a positional relationship among the first vehicle, the second vehicle and a pedestrian from a video and to generate monitoring information is installed in the intersection, and wherein the information acquisition unit is configured to acquire the monitoring information, the traffic status map generation unit is configured to generate the traffic status map reflecting the monitoring information, the threat mode determination unit is configured to determine a third threat mode for the first vehicle or the second vehicle regarded as a third threat target viewed from the pedestrian, and the monitoring device is configured to determine a third notification method for the pedestrian according to the third threat mode.

10. A drive assistance method comprising the steps of: wirelessly connecting with a first vehicle attempting to make a turn in a predetermined area and to move in a first moving direction and a second vehicle attempting to pass through the predetermined area in a second moving direction; acquiring first position information indicating a position of the first vehicle, gaze information indicating a gazing direction of a driver of the first vehicle, and second position information indicating a position of the second vehicle; generating a traffic status map by superimposing the first position information and the gaze information related to the first vehicle, and the second position information related to the second vehicle on a digital map indicating the predetermined area; calculating a first blind area invisible from the first vehicle in the traffic status map to determine a first threat mode for a first threat target viewed from the first vehicle; calculating a second blind area invisible from the second vehicle to determine a second threat mode for a second threat target viewed from the second vehicle; determining a first notification method for the driver of the first vehicle according to the first threat mode; and determining a second notification method for a driver of the second vehicle according to the second threat mode.

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