Patent ID: 12249240

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, the invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to claims. In addition, not all of the combinations of features described in the embodiments are essential to the solving means of the invention.

FIG.1schematically shows a usage scene of a warning system10. The warning system10includes a vehicle20and terminals82aand82b. The terminal82ais a terminal carried by a pedestrian80a, and the terminal82bis a terminal carried by a pedestrian80b. The pedestrians80aand80bmay be collectively referred to as “pedestrian80”. Moreover, the terminal82aand the terminal82bmay be collectively referred to as “terminal82”. The vehicle20is one example of a “moving body”.

In the warning system10, the vehicle20transmits warning information to the terminal82when there exists a pedestrian80having a risk of approaching the vehicle20. When receiving the warning information, the terminal82gives a warning to the pedestrian80by warning display, sound, vibration, or the like. In this way, the pedestrian80is notified of an approach of the vehicle20.

Note that the terminal82is an example of an “external terminal”. The terminal82may be a personal digital assistant such as a mobile phone or a smart phone. The terminal82includes a positioning function. The terminal82receives radio waves transmitted from a GNSS (Global Navigation Satellite System) satellite, for example, and measures a current position of the terminal82based on the radio waves transmitted from the GNSS (Global Navigation Satellite System) satellite. The terminal82periodically updates the current position of the terminal82by periodically performing positioning.

Note that in the present embodiment, a case where a “target” having a risk of approaching the vehicle20is a “pedestrian” will mainly be described. However, the “target” having the risk of approaching the vehicle20may be another moving body or vehicle. In this case, the “external terminal” may be a communication device such as a telematics control unit (TCU) provided in another vehicle.

The vehicle20includes a sensor29and a communication device24. The sensor29includes a camera and a radar. The sensor29acquires information in a range from a left borderline31to a right borderline32. For example, the sensor29acquires an image and distance measurement information in the range from the left borderline31to the right borderline32. The communication device24recognizes the image acquired by the camera to detect the pedestrian80. Further, the communication device24detects a current position of the pedestrian80based on the distance measurement information acquired by the radar and a current position of the vehicle20. The communication device24specifies a moving direction or the like of the pedestrian80based on an orientation or the like of the pedestrian80. The communication device24specifies, based on the current position and the moving direction of the pedestrian80, the pedestrian80who has a risk of approaching the vehicle20, in particular, who can be on a planned traveling route of the vehicle20.

For example, in the situation shown inFIG.1, the vehicle20is traveling on a roadway50. A sidewalk60is provided along with the roadway50. The sensor29detects the pedestrians80aand80bwalking on the sidewalk60. Since the pedestrian80bis facing a direction of walking on the sidewalk60in parallel with the roadway50, the communication device24determines that the pedestrian80bis unlikely to approach the vehicle20. On the other hand, since the pedestrian80ais facing a direction of heading to the roadway50, the communication device24determines that the pedestrian80ahas a risk of approaching the vehicle20.

For acquiring positional information of the terminal82a, the communication device24transmits request information for requesting positional information to the terminal82. At this time, the communication device24incorporates positional information indicating the position of the pedestrian80a, that has been detected by the sensor29, into the request information. Upon receiving the request information, the terminal82aperforms positioning using a positioning function of the terminal82awhen a distance between the position indicated by the positional information included in the request information and the current position of the terminal82ais smaller than a predetermined value. The terminal82atransmits response information including latest positional information obtained by the positioning and address information of the terminal82ato the vehicle20. On the other hand, upon receiving the request information, the terminal82bdetermines that a distance between the position indicated by the positional information included in the request information and the current position of the terminal82bis larger than the predetermined value and does not transmit the response information.

Upon receiving the response information from the terminal82a, the communication device24transmits warning information based on the positional information of the terminal82aincluded in the response information. For example, the communication device24eventually determines whether the pedestrian80ahas a risk of approaching the vehicle20based on the positional information of the terminal82aincluded in the response information and the moving direction or the like of the pedestrian80aspecified by the sensor29. When determining that the pedestrian80ahas a risk of approaching the vehicle20, the communication device24transmits warning information while setting the address information of the terminal82aincluded in the response information as a destination.

Upon receiving the warning information, the terminal82awarns the pedestrian80aby an HMI (Human Machine Interface) function of the terminal82a. Note that when receiving radio waves of the warning information transmitted from the vehicle20to the terminal82a, the terminal82bdetermines that the destination of the warning information is not the terminal82band does not warn the pedestrian80b.

As described above, the communication device24incorporates the positional information of the pedestrian80apredicted to approach the vehicle20into the request information and transmits it to the terminal82. Therefore, based on the positional information included in the request information and the current position of the terminal82a, the terminal82aperforms positioning after determining that a response should be made to the request information, and transmits the latest positional information of the terminal82ato the vehicle20. Accordingly, the communication device24can determine whether it is necessary to transmit the warning information using the latest positional information of the terminal82a. Then, when determining that it is not necessary to transmit the warning information, the communication device24can avoid transmitting the warning information. Accordingly, an increase of communication traffics can be suppressed.

When the request information for positional information is received, the terminal82bdetermines that there is no need to respond to the request information based on the positional information included in the request information and the current position of the terminal82b. Therefore, the terminal82bonly needs to discard the request information received from the vehicle20and does not need to additionally perform processing based on the request information. Further, since the terminal82bdoes not transmit response information, an increase of communication traffics can be suppressed.

Note that as a technique of detecting a physical body having a risk of approaching the vehicle20, there is a detection technique that uses distance measurement information and moving vectors obtained by a radar. However, this technique may misrecognize, for example, a physical body moving on a footbridge or an elevated road as a physical body approaching the vehicle20. To avoid such misrecognition, it is necessary to perform three-dimensional recognition processing with reference to three-dimensional map information. Moreover, since multiple times of measurement are required to calculate the moving vector, it may take some time to detect the physical body having a risk of approaching the vehicle20. In contrast, according to the warning system10, since a type or orientation of a physical body that approaches the vehicle20can be detected using an image recognition, the physical body that approaches the vehicle20can be detected appropriately as compared to a case where a physical body that approaches the vehicle20is detected using mainly the distance measurement information and the moving vectors.

Note that a range in which the sensor29acquires information, that is, the range from the left borderline31to the right borderline32may be variable depending on a velocity of the vehicle20or an external situation of the vehicle20. Making the range in which the sensor29acquires information variable depending on a vehicle velocity or an external situation of a vehicle, allows a physical body to be chosen that is more suitable for the situation.

Further, as described above, according to the warning system10, the communication device24transmits warning information based on the latest positional information obtained by the positioning by the terminal82. Therefore, it becomes possible to cause the terminal82aof the pedestrian80awho needs to be warned to perform warning, and cause the terminal82bof the pedestrian80bwho does not need to be warned not to perform warning. Thereby, it is possible to prevent a warning from being given to the pedestrian80who do not need a warning. Further, since it becomes possible to suppress unnecessary communication from being executed between the terminal82and the vehicle20, an increase of communication traffics can be suppressed. In particular, the terminal82bdoes not need to perform processing such as checking a position of the vehicle20approaching the pedestrian80bor communicating with the vehicle20.

Note that communication between the communication device24and the terminal82is executed by direct communication. For example, the communication device24directly communicates with the terminal82by short-range direct communication in Cellular-V2X. Short-range direct communication in Cellular-V2X includes a communication method such as LTE-V2X PC5 or 5G-V2X PC5 (abbreviated as “PC5” in the present embodiment). As the direct communication between the communication device24and the terminal82, a form that uses Wi-Fi (registered trademark) or DSRC (Dedicated Short Range Communications) may be adopted. As direct communication between the communication device24and the terminal82, any direct communication method such as Bluetooth (registered trademark) in addition to Cellular-V2X or DSRC (registered trademark) may be adopted. The communication device24may also use a communication infrastructure provided in ITS (Intelligent Transport Systems) to directly communicate with the terminal82.

FIG.2shows a system configuration of the vehicle20. The vehicle20includes the sensor29, the communication device24, and a driver-assistance control apparatus30.

The sensor29includes a radar21, a camera22, a GNSS reception unit25, and a vehicle velocity sensor26. The radar21may be LiDAR, a millimeter-wave radar, or the like. The GNSS reception unit25receives radio waves transmitted from a GNSS satellite. The GNSS reception unit25generates information indicating a current position of the vehicle20based on a signal received from the GNSS satellite. The camera22captures an image of a surrounding area of the vehicle20to generate image information. For example, the camera22captures an image in a traveling direction of the vehicle20to generate image information. Note that the sensor29may include a position sensor such as an odometer or IMU (Inertial Measurement Unit) such as an acceleration sensor or an attitude sensor.

The communication device24includes a processing unit200, a storage unit280, and a communication unit294. The processing unit200is realized by, for example, an arithmetic processing apparatus including a processor. The storage unit280is realized by including a nonvolatile storage medium. The processing unit200performs processing by using information stored in the storage unit280. The communication unit294is responsible for direct communication with the terminal82. The communication unit294includes a transmission unit290and a reception unit292. The processing unit200may be realized by an ECU (Electronic Control Unit) including a microcomputer equipped with a CPU, ROM, RAM, I/O, a bus, and the like.

The processing unit200includes a target locating unit210, a velocity calculation unit260, and a communication control unit270. The target locating unit210locates a position of a target having a risk of approaching the vehicle20. In the present embodiment, the “target having a risk of approaching the vehicle20” is, for example, a moving body, and may include at least one of a person or a vehicle. Moreover, “approaching” may include, for example, approaching the planned traveling route of the vehicle20or overlapping the planned traveling route. The target locating unit210may specify a position of a pedestrian having a risk of approaching the vehicle20. The target locating unit210includes an image acquisition unit220, an extraction unit222, a target distance acquisition unit230, a target position calculation unit240, and a moving body positional information acquisition unit250.

The moving body positional information acquisition unit250acquires positional information of the vehicle20. Specifically, the moving body positional information acquisition unit250acquires the positional information of the vehicle20from the GNSS reception unit25. The image acquisition unit220acquires an external image of the vehicle20. Specifically, the image acquisition unit220acquires from the camera22an image captured by the camera22. The extraction unit222extracts, from the image acquired by the image acquisition unit220, the target having a risk of approaching the vehicle20. The target distance acquisition unit230acquires a distance to the target extracted by the extraction unit222. Other than the image acquired by the image acquisition unit220, the target distance acquisition unit230may acquire a distance to the target using the radar21installed in the vehicle20or may fuse those together and acquire the distance based on statistical processing. The target distance acquisition unit230may acquire the distance to the target based on the image acquired by the image acquisition unit220. The target position calculation unit240calculates a position of a target having a risk of approaching the vehicle20based on the positional information of the vehicle20and the distance to the target.

The transmission unit290transmits request information including positional information of the terminal82as a positional information request target, based on the position of the target located by the target locating unit210. Upon receiving the request information, the terminal82transmits response information including the positional information obtained by the positioning by the terminal82. Note that the transmission unit290may include instruction information that instructs the terminal82to perform repositioning of the positional information of the terminal82. Upon receiving the request information, the terminal82performs repositioning and transmits response information including positional information obtained by the repositioning. The response information may include address information for directly or indirectly communicating with the terminal82.

The reception unit292receives the response information with respect to the request information. The transmission unit290transmits warning information based on the positional information of the terminal82included in the response information. For example, the target locating unit210may correct the positional information of the target based on the positional information of the terminal82included in the response information. The transmission unit290may transmit warning information including the positional information corrected by the target locating unit210. For example, the target locating unit210may specify the positional information of the terminal82included in the response information as the positional information of the target, and the transmission unit290may transmit warning information including the positional information of the terminal82included in the response information. As described above, the transmission unit290may transmit warning information including the positional information of the terminal82that is to output the warning, based on the positional information of the terminal82. By transmitting the warning information, the transmission unit290instructs the terminal82that has received the warning information to output the warning when the terminal82is positioned within a range determined based on the positional information included in the warning information.

Further, the target locating unit210may determine whether to warn the target based on the positional information of the terminal82included in the response information. The transmission unit290may transmit the warning information when the target locating unit210determines to warn the target. For example, the target locating unit210may re-determine whether the target has a risk of approaching the vehicle20based on the positional information of the terminal82included in the response information, the position of the vehicle20, the moving direction of the vehicle20, and the velocity of the vehicle20, and the transmission unit290may transmit the warning information when the target locating unit210determines that the target has a risk of approaching the vehicle20. When the address information of the terminal82is included in the response information, the transmission unit290may transmit the warning information while setting the address information as a destination.

Note that the transmission unit290may transmit the request information to the terminal82by direct communication. The transmission unit290may transmit the request information by broadcast. Further, the transmission unit290may transmit the warning information to the terminal82by direct communication. The transmission unit290may transmit the warning information by broadcast. Note that the transmission unit290may transmit at least one of the request information or the warning information by directional communication. For example, the transmission unit290may include a directional antenna so as to transmit at least one of the request information or the warning information toward a position of a target located by the target locating unit210.

The velocity calculation unit260calculates information on a moving velocity of the target extracted by the extraction unit222. For example, the velocity calculation unit260may calculate, based on a temporal change of the position calculated by the target position calculation unit240, the moving velocity of the target extracted by the extraction unit222. The velocity calculation unit260may calculate a relative velocity between the moving velocity of the target extracted by the extraction unit222and the moving velocity of the vehicle20detected by the vehicle velocity sensor26. The velocity calculation unit260may calculate the relative velocity between the moving velocity of the target extracted by the extraction unit222and the moving velocity of the vehicle20detected by the vehicle velocity sensor26based on a temporal change of the distance acquired by the target distance acquisition unit230. The velocity calculation unit260may also calculate the relative velocity based on the temporal change of the distance acquired by the target distance acquisition unit230.

The communication control unit270selects a transmission method that is used by the transmission unit290to transmit at least one of the request information or the warning information. The communication control unit may select the transmission method based on at least any of the moving velocity of the target, the moving velocity of the vehicle20, and the relative velocity between the vehicle20and the target. The communication control unit270may select the transmission method based on a category of the target.

The transmission method may include a first transmission method in which at least one of the request information or the warning information is transmitted at a first signal intensity and a second transmission method in which at least one of the request information or the warning information is transmitted at a second signal intensity different from the first signal intensity. The selection of the transmission method may include selecting one of the first transmission method and the second transmission method. Alternatively, the transmission method may include a first transmission method in which at least one of the request information or the warning information is transmitted to the terminal82associated with the target by unicast and a second transmission method in which at least one of the request information or the warning information is transmitted by broadcast. The selection of the transmission method may include selecting one of the first transmission method and the second transmission method.

The driver-assistance control apparatus30uses the information detected by the sensor29to assist driving of the vehicle20. The driver-assistance control apparatus30may be realized by an ECU having a function of ADAS (Advanced Driver-Assistance Systems).

FIG.3schematically shows an image300captured by the camera22.FIG.4schematically shows a situation where the image300has been acquired.

The image acquisition unit220acquires the image300from the camera22. The extraction unit222analyzes the image300to extract an object of the pedestrian80having a risk of approaching the vehicle20. For example, the extraction unit222extracts, from the image300, an object of a predetermined physical body such as a person or a vehicle which can be a “target” in this embodiment, to specify an orientation of each physical body based on the extracted object. The extraction unit222may specify the orientation of each physical body based on a shape of the object of the physical body. The extraction unit222specifies, based on the specified orientation, an object of a physical body having a risk of approaching the planned traveling route of the vehicle20.

For example, in an example ofFIG.3, an object310aand an object310bare an object of a person. The body of the object310ais facing toward the roadway50. On the other hand, the body of the object310bis not facing toward the roadway50. Therefore, the extraction unit222extracts the object310aas an object of the target having a risk of approaching the vehicle20.

The target distance acquisition unit230acquires distance measurement information from the radar21. The target distance acquisition unit230calculates a distance L from a reference position P1of the vehicle20to a position P2of the pedestrian80a, based on the distance measurement information acquired from the radar21and a position of the object310aon the image300. For example, the target distance acquisition unit230may cause the radar21to measure a distance to a physical body existing in a direction on a real space corresponding to the position of the object310a. Moreover, the target distance acquisition unit230may specify the distance L, by acquiring, from the radar21, distance measurement information on a plurality of points on a real space, and selecting, from the distance measurement information on the plurality of points, distance measurement information on a point corresponding to the position of the object310aon the image300. The target distance acquisition unit230may also specify the distance L by analyzing the image300. The target distance acquisition unit230may specify the distance L based on a size of an object in the image300. The target distance acquisition unit230may specify the distance L based on a blur amount and a color shift amount extracted from an area of the object310aof the image, by taking advantage of the fact that a blur amount and a color shift amount vary depending on a distance to a subject. The target distance acquisition unit230may specify the distance L based on disparity information acquired by the camera22. When the camera22is a twin-lens camera, the target distance acquisition unit230may specify the distance L by extracting the disparity information from an image acquired from the twin-lens camera. Moreover, the target distance acquisition unit230may also specify the distance L by fusing data on the distance L specified with a plurality of different techniques or by weighting and adding up the data.

The target position calculation unit240acquires the positional information of the vehicle20detected by the GNSS reception unit25. The target position calculation unit240calculates the position P2of the pedestrian80ainFIG.4, based on the reference position P1of the vehicle20based on the positional information detected by the GNSS reception unit25, the distance L acquired by the target distance acquisition unit230, and the position of the object310ain the image300. The communication control unit270generates request information including positional information that indicates the position P2. In the present embodiment, the positional information included in the request information is coordinate information that indicates a geographic position of the position P2. The communication control unit270causes the transmission unit290to transmit the request information.

Upon receiving the request information transmitted from the transmission unit290, each of the terminals82aand82bextracts the coordinate information of the position P2from the request information. The terminal82aand the terminal82beach determine whether the terminal82is near the point P2. For example, the terminal82aand the terminal82beach determine whether a distance between a current position of the terminal82and the point P2is equal to or smaller than a predetermined distance D1. Since the distance between the current position of the terminal82aand the point P2is equal to or smaller than D1, the terminal82adetermines that the terminal82ais near the point P2and performs positioning using GNSS signals.

Note that when the positioning is set to be performed periodically using the GNSS signals in the terminal82a, the terminal82amay perform positioning using the GNSS signals separate from the periodic positioning. Even when the periodic positioning using GNSS signals is prohibited in the terminal82a, the terminal82amay perform the positioning using GNSS signals upon receiving the request information. On the other hand, since the distance between the current position of the terminal82and the point P2exceeds D1, the terminal82bdetermines that the terminal82bis not near the point P2and discards the request information without performing repositioning according to the request information.

The terminal82atransmits response information including positional information that indicates a position of a point P3measured by the positioning to the vehicle20. When the reception unit292receives the response information in the vehicle20, the target position calculation unit240corrects the position of the pedestrian80abased on the point P3indicated by the positional information included in the response information.

As an example, the target position calculation unit240may determine that the pedestrian80ais positioned at the point P3. Further, assuming that the pedestrian80ais positioned within a distance D2from the point P3as a center, the target position calculation unit240may determine that the pedestrian80ais positioned at the point P3under a condition that the point P2specified before transmission of the request information is not within the distance D2. Then, the target locating unit210determines whether the pedestrian positioned at the point P3has a risk of approaching the vehicle20and when determined that the pedestrian positioned at the point P3has a risk of approaching the vehicle20, the transmission unit290transmits warning information to the terminal82a. Note that when a distance between the point P2specified before transmission of the request information and the point P3is equal to or smaller than the distance D2, the target position calculation unit240may judge that the pedestrian80ais positioned at the point P2. In this case, the warning information may be transmitted to the terminal82awithout judging whether the pedestrian80ahas a risk of approaching the vehicle20. Note that when transmitting the warning information to the terminal82a, the communication control unit270may generate warning information including positional information that indicates the point P3extracted from the response information, and cause the transmission unit290to transmit the warning information.

Upon receiving the warning information transmitted from the transmission unit290, the terminals82aand82beach extract coordinate information of the point P3from the warning information. The terminals82aand82brespectively determine whether the respective terminals82are near the point P3. For example, the terminals82aand82bdetermine whether distances between the current positions of the respective terminals82and the point P3are equal to or smaller than a predetermined distance D3. Since the distance between the current position of the terminal82aand the point P3is equal to or smaller than D3, the terminal82adetermines that the terminal82is near the point P3and outputs a warning. Note that D3and D1may be of the same length. D3may be shorter than D1. The transmission unit290may transmit request information including distance information that indicates D1. The transmission unit290may transmit warning information while incorporating therein the distance information that indicates D3.

Note that the velocity calculation unit260may calculate a velocity V2of the pedestrian80a. For example, the velocity calculation unit260may calculate the velocity V2of the pedestrian80abased on a temporal change amount of the position calculated by the target position calculation unit240. The communication control unit270may select a transmission method that is used by the transmission unit290to transmit the request information based on the velocity V2. The communication control unit270may also select the transmission method that is used by the transmission unit290to transmit the request information based on the velocity V1of the vehicle20. The communication control unit270may specify the velocity V1based on at least the velocity of the vehicle20detected by the vehicle velocity sensor26. The communication control unit270may specify the velocity V1based on a temporal change amount of the position of the vehicle20detected by the GNSS reception unit25. The communication control unit270may calculate a relative velocity between the vehicle20and the pedestrian80abased on the velocity V1and the velocity V2and select the transmission method used by the transmission unit290to transmit the request information based on the calculated relative velocity. Similarly, the communication control unit270may select the transmission method used by the transmission unit290to transmit the warning information based on the velocity V2. The communication control unit270may select the transmission method used by the transmission unit290to transmit the warning information based on the velocity V1of the vehicle20. The communication control unit270may select the transmission method used by the transmission unit290to transmit the warning information based on the relative velocity between the vehicle20and the pedestrian80a. An example of a method for the communication control unit270to determine the transmission method based on the velocity will be described later.

FIG.5schematically shows a flow of processing executed by the vehicle20and the terminals82aand82b.FIG.5will describe a case where a pedestrian is recognized as a target having a risk of approaching the vehicle20.

In S502, the extraction unit222extracts objects of pedestrians from an image acquired from the camera22. In S504, the extraction unit222determines whether there is a risk of approaching the vehicle20for each pedestrian corresponding to each extracted object. In S506, the target position calculation unit240calculates coordinates of the pedestrian having a risk of approaching the vehicle20.

In S508, the transmission unit290transmits request information including the coordinate information of the position of the pedestrian calculated in S506. At this time, the transmission unit290may transmit the request information by broadcast without designating the terminal82that is to become a destination of the warning information. The transmission unit290may designate the terminal82as the destination of the request information and transmit the request information by unicast. The transmission unit290may specify an address of a peripheral terminal82that has been acquired before transmitting the request information and transmit the request information to the terminal82by unicast. As an example, before causing the transmission unit290to transmit the request information after specifying the coordinates of the pedestrian in S506, the transmission unit290may acquire the address of the terminal82existing in a periphery of the vehicle20by direct communication and transmit warning information to the terminal82by unicast while setting the acquired address as the destination. The transmission unit290may acquire, based on beacon information transmitted from the terminal82existing in the periphery of the vehicle20, the address of the terminal82, and transmit the request information to the terminal82by unicast while setting the acquired address as the destination.

Upon receiving the request information from the communication device24, the terminal82adetermines whether to transmit the positional information to the vehicle20in S520. For example, in the example shown inFIG.4, the terminal82adetermines that the distance between the current position of the terminal82aand coordinates of the point P2included in the request information is equal to or smaller than D1. Therefore, the terminal82adetermines to transmit the positional information to the vehicle and performs positioning in S522. Note that the terminal82amay perform the positioning upon receiving the request information for the positional information and thereafter perform the determination of S520. In S524, response information including the coordinate information of the terminal82ameasured by the positioning is transmitted to the vehicle20. Note that the response information includes a terminal ID of the terminal82aas a transmission source of the response information. The terminal ID included in the response information is an example of the address information.

Meanwhile, in S530, the terminal82bdetermines that the distance between the current position of the terminal82band the point P2included in the request information exceeds D1. Accordingly, the terminal82bdetermines not to transmit the positional information to the vehicle and discards the request information without performing positioning. Note that the terminal82bmay perform the positioning upon receiving the request information for the positional information and thereafter perform the determination of S530.

When the reception unit292receives the response information in the vehicle20, in S510, the target position calculation unit240specifies a warning target based on the coordinate information of the terminal82aincluded in the response information. For example, in the example shown inFIG.4, the target position calculation unit240may assume that the pedestrian80ais positioned at the point P3included in the response information and determine that the pedestrian80ais to be the warning target when the pedestrian80ahas a risk of approaching the vehicle20. When determined that the pedestrian80ais to be the warning target, in S512, the transmission unit290transmits warning information while setting a terminal ID of a transmission source of the response information received in S524as a destination. When the terminal ID of the transmission destination of the warning information can be specified as described above, the transmission unit290may transmit the warning information by unicast.

Upon receiving the warning information from the communication device24, the terminal82awarns the pedestrian80ausing the HMI function of the terminal82ain S526. Note that although radio waves of the warning information transmitted from the communication device24are received, since the terminal82bdoes not correspond to the destination of the warning information, the terminal82bdiscards the warning information without performing warning.

Note that after transmitting the warning information in S512in the vehicle20, the driver-assistance control apparatus30performs driver assistance in S514. For example, when a predetermined condition is met, the driver-assistance control apparatus30may notify the pedestrian of approach of the vehicle20by decelerating the vehicle20or performing beam passing or horn announcement, with a function of an Advanced Emergency Braking System.

FIG.6schematically shows a flow of another processing executed by the vehicle20and the terminals82aand82b. The processing of S502, S504, S506, S508, S514, S520, S522, and S530shown inFIG.6is the same as the processing of S502, S504, S506, S508, S514, S520, S522, and S530shown inFIG.5, so descriptions thereof will be omitted.

After performing the positioning in S522, the terminal82atransmits the response information including the coordinate information of the terminal82ameasured by the positioning to the vehicle20in S624. Here, the response information does not include the terminal ID of the terminal82aas the transmission source of the response information.

When the reception unit292receives the response information in the vehicle20, in S610, the target position calculation unit240specifies a warning target based on the coordinate information of the terminal82aincluded in the response information. The processing of S610is the same as the processing of S510, so descriptions thereof will be omitted. When it is determined in S610that the pedestrian80ais to be the warning target, the transmission unit290transmits warning information including the positional information received in S624in S612. When address information of the terminal82as the transmission destination of the warning information is unknown, the transmission unit290may transmit the warning information including the positional information by broadcast without designating the terminal82as a destination of the warning information.

Upon receiving the warning information transmitted from the communication device24, the terminal82adetermines whether to perform warning in S626. For example, in the example shown inFIG.4, the terminal82adetermines that the distance between the current position of the terminal82aand the coordinates of the point P3included in the warning information is equal to or smaller than D3. Therefore, the terminal82auses the HMI function of the terminal82ato give a warning to the pedestrian80ain S628. On the other hand, in S632, the terminal82bdetermines that the distance between the current position of the terminal82band the coordinates of the point P3included in the warning information exceeds D3. Accordingly, the terminal82bdiscards the warning information without giving a warning.

Note that the form in which the transmission unit290transmits the warning information by unicast when the terminal ID is included in the response information has been described in association withFIG.5. Further, the form in which the warning information including the coordinate information of the terminal82is transmitted by broadcast when the terminal ID is not included in the response information has been described in association withFIG.6. However, the processing ofFIGS.5and6may be combined arbitrarily. For example, in S512ofFIG.5, the warning information including the coordinate information of the terminal82may be transmitted to the terminal82aby unicast so that the terminal82athereafter performs the processing of S626. Further, in S512ofFIG.5, the warning information including the coordinate information of the terminal82amay be transmitted by broadcast so that the terminal82athereafter performs the processing of S626.

FIG.7shows a data structure of transmission method information referred to by the communication control unit270to specify the transmission method. The transmission method information associates a category, a velocity, and a transmission method. Referring to the transmission method information, the communication control unit270determines the transmission method for transmitting at least one of the request information or the warning information. The transmission method information is stored in the storage unit280. Note that to prevent descriptions from becoming redundant, the request information and the warning information will be referred to as “transmission information” in descriptions ofFIG.7.

A “category” is information for identifying a category of a physical body which can be a target of a warning such as a “pedestrian” or an “automobile”, for example A “velocity” is information for indicating a range of a velocity of a physical body which can be a target of a warning.

The “transmission method” is information for identifying the transmission method for the transmission information. The “transmission method” may include information defining a transmission signal intensity of the transmission information. For example, the “method 2” may be a transmission method in which transmission is performed at a higher signal intensity than the “method 1”.

The “transmission method” may include information defining which of unicast transmission and broadcast transmission the transmission information is to be transmitted by. For example, the “method 1” may be “unicast”, and the “method 2” may be “broadcast”.

The “transmission method” may include information defining the number of times the transmission information is to be repeatedly transmitted in the case of broadcast transmission. For example, the “method 2” may be a transmission method in which transmission is performed with a larger number of repeated transmissions than the “method 1”.

The “transmission method” may include information defining a period for repeatedly transmitting the transmission information in the case of broadcast transmission. For example, the “method 2” may be a transmission method in which transmission is performed with a longer period of repeated transmissions than the “method 1”.

The “transmission method” may include information defining a frequency of repeatedly transmitting the transmission information in the case of broadcast transmission. For example, the “method 2” may be a transmission method in which transmission is performed with a higher frequency of repeated transmissions than the “method 1”. The “transmission method” may include information defining a time interval for repeatedly transmitting the transmission information in the case of broadcast transmission. For example, the “method 2” may be a transmission method in which transmission is performed at a shorter interval of repeated transmissions than the “method 1”.

The “transmission method” may include information defining whether to perform retransmission control of the transmission information in unicast transmission. For example, the “method 1” may be a transmission method in which no retransmission control is performed, and the “method 2” may be a transmission method in which retransmission control is performed.

The “transmission method” may include information indicating the number of retransmission attempts by which the transmission information is attempted to be retransmitted in unicast transmission. For example, the “method 2” may be a transmission method in which transmission is performed with a larger number of retransmission attempts than the “method 1”.

The “transmission method” may include information for identifying whether to transmit the transmission information by PC5. The “transmission method” may include information for identifying whether to transmit the transmission information by DSRC (registered trademark). The “transmission method” may include information for identifying whether to transmit the transmission information by Bluetooth (registered trademark). For example, the “method 1” may indicate that the transmission information is to be transmitted by DSRC (registered trademark), and the “method 2” may indicate that the transmission information is to be transmitted by PC5.

The communication control unit270selects, in the transmission method information, a transmission method associated with a combination of a category specified by the target locating unit210and a moving velocity calculated by the velocity calculation unit260, to perform transmission by the selected transmission method. As an example, described will be a case where the “method 1” is a “unicast” transmission method and the “method 2” is a “broadcast” transmission method. When the velocity is higher than a predetermined velocity, the communication control unit270selects at least a “broadcast” transmission method with reference to the transmission method information. Specifically, if a category of a warning target is a pedestrian, when a velocity of the pedestrian is 2 km/s or less, the communication control unit270selects “unicast”, and when the velocity of the pedestrian exceeds 2 km/s, the communication control unit270selects “broadcast”. If a category of a warning target is an automobile, when a vehicle velocity of the automobile is 5 km/s or less, the communication control unit270selects “unicast”, and when the vehicle velocity exceeds 5 km/s, the communication control unit270selects “broadcast”. Note that the “transmission method” may determine a combination of a plurality of transmission methods. For example, the “transmission method” may define that the transmission information is to be transmitted by “unicast” and “broadcast” in association with the case where the vehicle velocity of the automobile exceeds 5 km/s.

As described above, the communication control unit270selects the transmission method for the transmission information based on the category of the target extracted by the extraction unit222. Accordingly, the communication control unit270can select the transmission method for the transmission information according to a risk level that is based on the category of the target and the moving velocity of the target. Note that the above-described selection of the transmission method is merely an example. For the selection of the transmission method, an optimal transmission method only has to be selected, in total consideration of a category of a target, risk of the target approaching the vehicle20, time taken for the target to approach the vehicle20, communication reliability, a degree of communication congestion, or the like. For example, there may be a case where the “method 1” is “broadcast” and the “method 2” is “unicast”.

Note that the transmission unit290may transmit transmission information including category information that indicates a category of the target extracted by the extraction unit222. When the transmission information is received, the terminal82may extract the category information included in the transmission information and determine not to perform warning or positioning when the extracted category information does not coincide with predetermined category information of the terminal82. For example, when the vehicle20transmits transmission information including the category information of “pedestrian”, another vehicle that has received the transmission information may determine not to perform warning or positioning since it does not coincide with the category indicated by the category information included in the transmission information.

FIG.8shows a flowchart according to a communication method executed by the communication device24. The communication device24repeatedly executes processing from a starting point S700of a warning processing loop to an ending point S728of the warning processing loop. When a predetermined condition is met in at least one of the starting point S700of the warning processing and the ending point S728of the warning processing, the communication device24ends the warning processing loop.

In S702, the moving body positional information acquisition unit250and the velocity calculation unit260respectively acquire a current position and a moving velocity of the vehicle20. For example, the moving body positional information acquisition unit250acquires positional information successively output from the GNSS reception unit25. Further, the velocity calculation unit260acquires velocity information successively output from the vehicle velocity sensor26.

In S704, the extraction unit222extracts, from an image acquired by the image acquisition unit220from the camera22, a target having a risk of approaching the vehicle20. Moreover, the extraction unit222specifies, from the image, a category of the target having a risk of approaching the vehicle20.

In S706, the target distance acquisition unit230determines whether the target having a risk of approaching the vehicle20has been extracted. When no target having a risk of approaching the vehicle20has been extracted, the processing advances to S728. On the other hand, when a target having a risk of approaching the vehicle20has been extracted, the target distance acquisition unit230acquires in S708a distance to the target extracted in S704. The target distance acquisition unit230acquires, based on the distance measurement information from the radar21or an analysis result of the image acquired by the image acquisition unit220, the distance to the target extracted in S704.

In S710, the target position calculation unit240calculates a position of the target extracted in S704. Specifically, the target position calculation unit240calculates, based on the position of the vehicle acquired in S702, the distance to the target acquired in S708, and the position of the target in the image, geographic coordinates indicating the position of the target extracted in S704.

In S712, the velocity calculation unit260calculates a moving velocity of the target extracted in S704. For example, the velocity calculation unit260may calculate, based on a temporal change amount of the position of the target extracted in S704, the velocity of the target extracted in S704. The velocity calculation unit260may also calculate a relative moving velocity between the target and the vehicle20.

In S714, the communication control unit270selects a transmission method for request information based on the moving velocity calculated in S712and the category of the target extracted in S704.

In S716, the transmission unit290transmits request information including the coordinates of the target calculated in S710according to the transmission method selected in S714. In S718, the reception unit292receives response information including the coordinate information of the terminal82. In S720, the target position calculation unit240corrects the position of the target based on the coordinate information included in the response information. For example, the target position calculation unit240may assume that the coordinate information included in the response information is the positional information of the target.

In S722, the target locating unit210determines whether the target has a risk of approaching the vehicle20. When determined that the target has no risk of approaching the vehicle20, the processing advances to S728. On the other hand, when determined that the target has a risk of approaching the vehicle20, in S724, the communication control unit270selects a transmission method for warning information based on the moving velocity calculated in S712and the category of the target extracted in S704. Then, in S726, the transmission unit290transmits the warning information according to the transmission method selected in S724.

According to the warning system10described above, since the communication device24transmits the request information including the positional information, it becomes possible to suppress a situation where the terminal82of the pedestrian80who has no risk of approaching the vehicle20performs positioning. Further, the communication device24can determine whether it is necessary to warn the pedestrian80using latest positional information obtained by the positioning by the terminal82. Furthermore, the communication device24can transmit warning information based on the latest positional information of the terminal82. Therefore, it becomes possible to suppress a situation where the pedestrian80who does not need to be warned is warned. Moreover, it is possible to suppress occurrence of unnecessary communication between the terminals82and the vehicle20. Furthermore, according to the warning system10, each of the terminals82only needs to calculate the distance between the positional information included in the request information or the warning information and the current position of the terminal82and does not need to perform processing of checking the position of the vehicle20approaching the pedestrian80or the like. Therefore, a load on the terminal82can be reduced.

Note that the vehicle20is one example of transport equipment. The transport equipment includes an automobile such as a passenger vehicle or a bus, a saddle-type vehicle, a bicycle, and the like. In addition, the moving body includes not only a person but also transport equipment, for example, an automobile such as a passenger vehicle or a bus, a saddle-type vehicle, and a bicycle.

FIG.9shows an example of a computer2000in which a plurality of embodiments of the present invention may be entirely or partially embodied. Programs installed in the computer2000can cause the computer2000to: function as apparatuses such as the communication device24according to the embodiments, or each unit of the apparatuses; execute operations associated with the apparatuses or each unit of the apparatuses; and/or execute a process according to the embodiments or steps of the process. Such a program may be executed by a CPU2012to cause the computer2000to execute the specific operation associated with some or all of the blocks of processing procedures and block diagrams described in the present specification.

The computer2000according to the present embodiment includes the CPU2012and a RAM2014, which are connected mutually by a host controller2010. The computer2000also includes a ROM2026, a flash memory2024, a communication interface2022, and an input/output chip2040. The ROM2026, the flash memory2024, the communication interface2022, and the input/output chip2040are connected to the host controller2010via an input/output controller2020.

The CPU2012operates according to the program stored in the ROM2026and the RAM2014, thereby controlling each unit.

The communication interface2022communicates with other electronic devices via a network. The flash memory2024stores the program and data used by the CPU2012in the computer2000. The ROM2026stores a boot program or the like executed by the computer2000during activation, and/or a program depending on hardware of the computer2000. In addition, the input/output chip2040may connect various input/output units such as a keyboard, a mouse, and a monitor to the input/output controller2020via an input/output port such as a serial port, a parallel port, a keyboard port, a mouse port, a monitor port, a USB port, and an HDMI (registered trademark) port.

The program is provided via a network or a computer-readable medium such as a CD-ROM, a DVD-ROM, or a memory card. The RAM2014, the ROM2026, or the flash memory2024is an example of the computer-readable medium. The program is installed in the flash memory2024, the RAM2014, or the ROM2026and executed by the CPU2012. Information processing written in these programs is read by the computer2000, resulting in cooperation between a program and the above-described various types of hardware resources. An apparatus or method may be constituted by realizing the operation or processing of information in accordance with the usage of the computer2000.

For example, when communication is executed between the computer2000and an external device, the CPU2012may execute a communication program loaded in the RAM2014, and instruct the communication interface2022to process the communication based on the processing written in the communication program. The communication interface2022, under the control of the CPU2012, reads out transmission data stored in a transmission buffer processing area provided in a recording medium such as the RAM2014and the flash memory2024, transmits the read transmission data to the network, and writes reception data received from the network into a reception buffer processing area or the like provided on the recording medium.

In addition, the CPU2012may cause all or a necessary portion of a file or a database to be read into the RAM2014, the file or the database having been stored in the recording medium such as the flash memory2024, and execute various types of processing on the data on the RAM2014. The CPU2012, then, writes back the processed data into the recording medium.

Various types of information, such as various types of programs, data, tables, and databases, may be stored in the recording medium to undergo information processing. The CPU2012may execute, on the data read from the RAM2014, various types of processing including various types of operations, processing of information, conditional judgment, conditional branching, unconditional branching, search and replacement of information, and the like described in the present specification and specified by instruction sequences of the programs, and writes a result back to the RAM2014. The CPU2012may also search for information in a file, a database, and the like in the recording medium. For example, when a plurality of entries, each having an attribute value of a first attribute associated with an attribute value of a second attribute, are stored in the recording medium, the CPU2012may search for an entry matching the condition whose attribute value of the first attribute is designated, from among the plurality of entries, and read the attribute value of the second attribute stored in the entry, thereby obtaining the attribute value of the second attribute associated with the first attribute satisfying the predetermined condition.

The program or software module described above may be stored in a computer-readable medium on the computer2000or near the computer2000. A recording medium such as a hard disk or a RAM provided in a server system connected to a dedicated communication network or the Internet can be used as a computer-readable medium. The programs stored in the computer-readable medium may be provided to the computer2000via the network.

The program installed in the computer2000and causing the computer2000to function as the communication device24may instruct the CPU2012or the like to cause the computer2000to function as each unit of the communication device24. The information processing written in these programs are read by the computer2000to cause the computer to function as each unit of the communication device24, which is a specific means realized by the cooperation of software and the various types of hardware resources described above. Then, these specific means realize operations or processing of information corresponding to the intended use of the computer2000in this embodiment, so that the communication device24is constructed as a specific communication device corresponding to the intended use.

Various embodiments have been described with reference to the block diagrams and the like. In the block diagram, each block may represent (1) a step of a process in which an operation is performed, or (2) each unit of the apparatus having a role of performing the operation. Specific steps and each unit may be implemented by a dedicated circuit, a programmable circuit supplied along with a computer-readable instruction stored on a computer-readable medium, and/or a processor supplied along with the computer-readable instruction stored on the computer-readable medium. The dedicated circuit may include a digital and/or analog hardware circuit, or may include an integrated circuit (IC) and/or a discrete circuit. The programmable circuit may include a reconfigurable hardware circuit including logical AND, logical OR, logical XOR, logical NAND, logical NOR, and other logical operations, a memory element such as a flip-flop, a register, a field programmable gate array (FPGA), and a programmable logic array (PLA), and the like.

The computer-readable medium may include any tangible device capable of storing an instruction to be executed by an appropriate device, so that the computer-readable medium having the instruction stored thereon constitutes at least a part of a product including an instruction that may be executed in order to provide means to execute an operation specified by a processing procedure or a block diagram. Examples of the computer-readable medium may include an electronic storage medium, a magnetic storage medium, an optical storage medium, an electromagnetic storage medium, a semiconductor storage medium, and the like. More specific examples of the computer-readable medium may include a floppy (registered trademark) disk, a diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an electrically erasable programmable read-only memory (EEPROM), a static random access memory (SRAM), a compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a Blu-ray (registered trademark) disc, a memory stick, an integrated circuit card, and the like.

Computer-readable instructions may include assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk (registered trademark), JAVA (registered trademark), and C++, and conventional procedural programming languages, such as the “C” programming language or similar programming languages.

Computer-readable instructions may be provided to a processor of a general-purpose computer, special purpose computer, or other programmable data processing apparatuses, or to a programmable circuit, locally or via a local area network (LAN), wide area network (WAN) such as the Internet, etc., so that the computer-readable instructions are executed to create means for performing operations specified in the described processing procedures or block diagrams. Examples of the processor include a computer processor, a processing unit, a microprocessor, a digital signal processor, a controller, a microcontroller, and the like.

While the embodiments of the present invention have been described, the technical scope of the invention is not limited to the above described embodiments. It is apparent to persons skilled in the art that various alterations and improvements can be added to the above-described embodiments. It is also apparent from the scope of the claims that the embodiments added with such alterations or improvements can be included in the technical scope of the invention.

The operations, procedures, steps, and stages of each process performed by a device, system, program, and method shown in the claims, embodiments, or diagrams can be performed in any order as long as the order is not indicated by “prior to,” “before,” or the like and as long as the output from a previous process is not used in a later process. Even if the process flow is described using phrases such as “first” or “next” in the claims, embodiments, or diagrams, it does not necessarily mean that the process must be performed in this order.

Explanation of References

10: warning system;20: vehicle;21: radar;22: camera;24: communication device;25: GNSS reception unit;26: vehicle velocity sensor;29: sensor;30: driver-assistance control apparatus;50: roadway;60: sidewalk;80: pedestrian;82: terminal;100: vehicle;200: processing unit;210: target locating unit;220: image acquisition unit;222: extraction unit;230: target distance acquisition unit;240: target position calculation unit;250: moving body positional information acquisition unit;260: velocity calculation unit;270: communication control unit;280: storage unit;290: transmission unit;292: reception unit;294: communication unit;300: image;310: object;2000: computer;2010: host controller;2012: CPU;2014: RAM;2020: input/output controller;2022: communication interface;2024: flash memory;2026: ROM;2040: input/output chip