Parking assistance method, parking assistance device, and parking assistance system

Abstract

In a parking assistance method, a controller is made to carry out a first parking assistance function of, on the basis of parking assistance information including information of a candidate parking location stored in association with location information of a known target around a host vehicle, and location information of a target detected around the host vehicle by a sensor mounted on the host vehicle, setting a candidate parking location corresponding to the location information of the detected target as a target parking location of the host vehicle and assisting the parking of the host vehicle in the target parking location. The controller determines whether another vehicle present around the host vehicle has requested transmission of the parking assistance information (S1), determines the degree of safety in transmitting the parking assistance information from the host vehicle to the other vehicle (S2), and transmits the parking assistance information from the host vehicle to the other vehicle when the degree of safety is at least a first threshold and transmission of the parking assistance information is requested by the other vehicle (S4).

Description

Parking assistance method, parking assistance device, and parking assistance system

[0001] The present invention relates to a parking assistance method, a parking assistance device, and a parking assistance system.

[0002] The parking assistance device described in Patent Document 1 extracts feature points from an image captured of an area where the driver wishes to register a parking position, and registers the feature points in association with the parking position, thereby registering the parking position as a registered parking position.When the vehicle is located near the registered parking position, the device detects the feature points to calculate the registered parking position, and performs parking assistance control to park the vehicle at the registered parking position.

[0003] Japanese Patent Application Laid-Open No. 2023-145476

[0004] However, information on the registered parking position of the vehicle (information on feature points and parking position) may contain private information that can identify the user of the vehicle, and if the registered parking position information is transmitted to other vehicles without restriction, there is a risk that the privacy of the user of the vehicle will be compromised.The present invention aims to prevent the privacy of the user of the vehicle from being compromised when parking assistance information including information on landmarks around the parking position used by the vehicle and information on the parking position is used by the parking assistance function of another vehicle.

[0005] According to one aspect of the present invention, there is provided a parking assistance method that causes a controller to implement a first parking assistance function that sets a candidate parking position corresponding to the position information of the detected target as a target parking position of the host vehicle based on parking assistance information including information on candidate parking positions stored in association with position information of known targets around the host vehicle and position information of targets detected around the host vehicle by a sensor mounted on the host vehicle, and assists in parking the host vehicle at the target parking position. The controller determines whether another vehicle around the host vehicle has requested transmission of the parking assistance information, determines a safety level for transmitting the parking assistance information from the host vehicle to the other vehicle, and transmits the parking assistance information from the host vehicle to the other vehicle if the safety level is equal to or greater than a first threshold and transmission of the parking assistance information has been requested by the other vehicle.

[0006] According to the present invention, when parking assistance information including information on targets around a parking position used by the vehicle and information on the parking position is used by a parking assistance function of another vehicle, it is possible to prevent the privacy of the user of the vehicle from being compromised. The objects and advantages of the present invention are realized and achieved by using the elements and combinations set forth in the claims. It should be understood that both the foregoing general description and the following detailed description are merely exemplary and explanatory and are not intended to limit the invention as defined by the claims.

[0007] 1 is a diagram illustrating an example of a schematic configuration of a parking assistance system according to an embodiment; (a) and (b) are schematic diagrams illustrating an example of a first parking assistance function; (b) is a schematic diagram illustrating an example of a third parking assistance function; (c) is a flowchart of an example of a parking assistance method according to an embodiment; (d) is a flowchart of an example of a safety level determination process; (a) to (c) are schematic diagrams illustrating an example of a map data generation process;

[0008] (Configuration) FIG. 1 is a diagram showing an example of the schematic configuration of a parking assistance system according to an embodiment. The parking assistance system 100 includes a host vehicle 1A and another vehicle 1B equipped with a parking assistance function that assists in parking the vehicle at a target parking position. The host vehicle 1A and the other vehicle 1B are equipped with a first parking assistance device 10A and a second parking assistance device 10B, respectively, that assist in parking the host vehicle 1A and the other vehicle 1B at the target parking position. The host vehicle 1A and the other vehicle 1B are examples of the "first vehicle" and the "second vehicle" described in the claims. In the following description, the host vehicle 1A and the other vehicle 1B may be collectively referred to as "vehicle 1," and the first parking assistance device 10A and the second parking assistance device 10B may be collectively referred to as "parking assistance device 10."

[0009] The parking assistance device 10 executes parking assistance control, which is control that assists the vehicle 1 in traveling along a target traveling route from the current position of the vehicle 1 to a target parking position. For example, the parking assistance control may be automatic driving control that controls the vehicle 1 to travel along the target traveling route of the vehicle 1 to a target parking position. Automatic driving control that controls the vehicle 1 to travel along the target traveling route of the vehicle 1 to a target parking position means control that automatically performs all or part of the traveling of the vehicle 1 along the target traveling route by controlling all or part of the steering angle, driving force, and braking force of the vehicle. Furthermore, for example, the parking assistance control may be control that assists the user in parking the vehicle 1 by displaying the target traveling route and the current position of the vehicle 1 on a display device that is visible to the occupants of the vehicle 1.

[0010] The first parking assistance device 10A of the host vehicle 1A includes an external sensor 11A, a vehicle sensor 12A, a communication device 13A, a positioning device 14A, a controller 15A, and an actuator (ACTR) 16A. The external sensor 11A detects objects within a predetermined distance range from the host vehicle 1A. The external sensor 11A detects the surrounding environment of the host vehicle 1A, such as the relative position of the host vehicle 1A and an object present around the host vehicle 1A, the distance between the host vehicle 1A and the object, and the direction in which the object is present. The external sensor 11A may include, for example, a camera that captures the surrounding environment of the host vehicle 1A. In the following description, the camera included in the external sensor 11A will be simply referred to as the "first camera." The external sensor 11A may include a ranging device such as a laser range finder, radar, or LiDAR (Light Detection and Ranging).

[0011] The vehicle sensor 12A detects various information (vehicle information) about the host vehicle 1A. The vehicle sensor 12A may include, for example, a vehicle speed sensor that detects the traveling speed of the host vehicle 1A, a wheel speed sensor that detects the rotational speed of each tire of the host vehicle 1A, a three-axis acceleration sensor (G sensor) that detects the acceleration (including deceleration) of the host vehicle 1A in three axial directions, a steering angle sensor that detects the steering angle, a steering angle sensor that detects the steering angle of the steered wheels, a gyro sensor, and a yaw rate sensor. The communication device 13A provides a communication function between the first parking assistance device 10A and an external device. The communication method used by the communication device 13A may be, for example, wired communication or wireless communication via a public mobile communication network, satellite communication, or vehicle-to-vehicle communication with a vehicle other than the host vehicle 1A (e.g., another vehicle 1B). The controller 15A transmits and receives data to and from the other vehicle 1B via the communication device 13A. The positioning device 14A measures the host vehicle 1A's current position and attitude (e.g., the longitudinal direction of the vehicle body). Positioning device 14A comprises a Global Navigation Satellite System (GNSS) receiver, such as a Global Positioning System (GPS) receiver.

[0012] The controller 15A is an electronic control unit that performs parking assistance control of the host vehicle 1A. The controller 15A includes a processor 17A and peripheral components such as a storage device 18A. The processor 17A may be, for example, a CPU or an MPU. The storage device 18A may include a semiconductor storage device, a magnetic storage device, an optical storage device, or the like. The functions of the controller 15A described below are realized, for example, by the processor 17A executing a computer program stored in the storage device 18A. The actuator 16A operates the steering device, drive device, and braking device of the host vehicle 1A in response to control signals generated by the controller 15A to generate vehicle behavior of the host vehicle 1A, thereby automatically driving the host vehicle 1A. The actuator 16A includes a steering actuator that operates the steering device, an accelerator opening actuator that operates the drive device, and a brake control actuator that operates the braking device.

[0013] The second parking assistance device 10B of the other vehicle 1B includes an external sensor 11B, a vehicle sensor 12B, a communication device 13B, a positioning device 14B, a controller 15B, and an actuator 16B. The external sensor 11B, the vehicle sensor 12B, the positioning device 14B, and the actuator 16B of the other vehicle 1B may have configurations and functions similar to those of the external sensor 11A, the vehicle sensor 12A, the positioning device 14A, and the actuator 16A of the host vehicle 1A. In the case of the external sensor 11B, the vehicle sensor 12B, the positioning device 14B, and the actuator 16B, the term "host vehicle 1A" in the above description of the external sensor 11A, the vehicle sensor 12A, the positioning device 14A, and the actuator 16A should be read as "other vehicle 1B," "first camera" should be read as "second camera," and "controller 15A" should be read as "controller 15B."

[0014] The communication device 13B provides a communication function between the second parking assistance device 10B and an external device. The communication method used by the communication device 13B may be, for example, wired communication or wireless communication via a public mobile communication network, satellite communication, or vehicle-to-vehicle communication with a vehicle other than the other vehicle 1B (for example, the host vehicle 1A). The controller 15B transmits and receives data to and from the host vehicle 1A via the communication device 13B.

[0015] The controller 15B is an electronic control unit that performs parking assistance control for the other vehicle 1B. The controller 15B includes a processor 17B and peripheral components such as a storage device 18B. The processor 17B may be, for example, a CPU or an MPU. The storage device 18B may include a semiconductor storage device, a magnetic storage device, an optical storage device, or the like. The functions of the controller 15B described below are realized, for example, by the processor 17B executing a computer program stored in the storage device 18B.

[0016] Next, a parking assistance function that assists in parking the vehicle 1 will be described. In this specification, a first parking assistance function, a second parking assistance function, and a third parking assistance function will be exemplified. The first parking assistance function is a function that assists in parking the vehicle 1A at the target parking position based on information on known targets around the candidate parking positions, information on the candidate parking positions, and position information on targets detected around the vehicle 1A by a sensor mounted on the vehicle 1A. The first parking assistance function is a function that assists in parking the vehicle 1A at the target parking position based on information on known targets around the candidate parking positions, information on the candidate parking positions, and position information on targets detected around the vehicle 1A by a sensor mounted on the vehicle 1A. The second parking assistance function is a function that assists in parking the vehicle 1B at the target parking position based on information on known targets around the candidate parking positions, information on the candidate parking positions, and position information on targets detected around the vehicle 1B by a sensor mounted on the vehicle 1B. The third parking assistance function provided by the other vehicle 1B may be the same function as the first parking assistance function provided by the own vehicle 1A, and as long as the basic parts are common, the additional functions added to each may be different.

[0017] An example of the first parking assist function will be described with reference to FIGS. 2(a) and 2(b). In the case of the second parking assist function, the terms "first parking assist function," "host vehicle 1A," "first parking assist device 10A," "storage device 18A," and "external sensor 11A" in the following description will be replaced with "second parking assist function," "other vehicle 1B," "second parking assist device 10B," "storage device 18B," and "external sensor 11B." When using the first parking assist function, a candidate parking position 31, which is a candidate for the target parking position where the host vehicle 1B should be parked, is registered in advance in the first parking assist device 10A. Specifically, targets present around the candidate parking position 31 are extracted and stored (registered) in the storage device 18A. In the following description, the targets around the candidate parking position 31 stored in the storage device will be referred to as "learned targets." In FIG. 2(a), circles schematically represent learned targets. This also applies to FIGS. 6(a) to 6(c) described below. The learned target is an example of a "known target" as defined in the claims.

[0018] For example, when the host vehicle 1A is located near the candidate parking position 31 (for example, when the user manually parks the host vehicle 1A at the candidate parking position 31), the first parking assistance device 10A detects targets around the host vehicle 1A using the external environment sensor 11A mounted on the host vehicle 1A and stores the targets as learned targets. For example, the targets may be detected from a surrounding image obtained by capturing an image of the surroundings of the host vehicle 1A with a camera. For example, the first parking assistance device 10A may detect, as targets, edge points or points (feature points) with characteristic shapes where the brightness of adjacent pixels changes by a predetermined amount or more, such as edges or corners of targets such as road markings, road boundaries, and obstacles in the captured image obtained by the camera.

[0019] The first parking assistance device 10A stores parking assistance information, which is data related to the candidate parking position 31, in the storage device 18A. For example, the parking assistance information may include data representing the feature amounts of the learned target (hereinafter referred to as "feature amount data") and data representing the relative positional relationship between the candidate parking position 31 and the position of the learned target (hereinafter referred to as "relative position data"). The relative position data may store, for example, the relative position of the learned target with respect to the candidate parking position 31. For example, the first parking assistance device 10A may acquire the position of the learned target detected when the host vehicle 1A is parked at the candidate parking position 31 as the relative position of the learned target with respect to the candidate parking position 31. The first parking assistance device 10A may store the coordinates of the learned target and the candidate parking position 31 in a coordinate system (hereinafter referred to as "map coordinate system") with a fixed point as the reference point. The first parking assistance device 10A may also detect an obstacle O1 around the candidate parking position 31 using the external environment sensor 11A. The parking assistance information may include obstacle data that indicates the relative positional relationship between the candidate parking position 31 and the obstacle O1.

[0020] FIG. 2(b) shows a scene in which the first parking assistance function is used to park the host vehicle 1A (hereinafter, this may be referred to as "when parking assistance is being performed"). When parking assistance is being performed, the external sensor 11A extracts targets around the host vehicle 1A. In the following description, targets around the host vehicle 1A extracted when parking assistance is being performed are referred to as "surrounding targets." In FIG. 2(b), triangular plots schematically represent surrounding targets. The first parking assistance device 10A matches the learned targets with the surrounding targets to associate identical feature points, and calculates the relative position of the candidate parking position 31 with respect to the host vehicle 1A based on the relative positional relationship between the surrounding targets detected when parking assistance is being performed and the host vehicle 1A, and the relative positional relationship between the learned targets associated with the surrounding targets and the candidate parking position 31.

[0021] For example, the first parking assistance device 10A calculates the position of the candidate parking position 31 in a coordinate system (hereinafter referred to as the "vehicle coordinate system") based on the current position of the host vehicle 1A. Note that if the relative position data includes coordinates of the learned targets and the candidate parking position 31 in the map coordinate system, the coordinates of the candidate parking position 31 in the map coordinate system may be converted to coordinates in the vehicle coordinate system based on the positions of the surrounding targets detected during parking assistance and the positions of the learned targets in the map coordinate system. The first parking assistance device 10A may calculate the relative position of the obstacle O1 with respect to the host vehicle 1A using a similar method. The first parking assistance device 10A sets the candidate parking position 31 as a target parking position and calculates a target parking path 34 from the current position 33 of the host vehicle 1A to the target parking position based on the relative position of the candidate parking position 31 with respect to the host vehicle 1A. The parking assistance device 10A may calculate the target parking path 34 so as to avoid the obstacle O1. The first parking assistance device 10A performs parking assistance control for the host vehicle 1A based on the calculated target parking path 34.

[0022] On the other hand, the third parking assistance function detects the relative positional relationship of a target parking position with respect to the current position of the host vehicle 1A or the other vehicle 1B, and assists the host vehicle 1A or the other vehicle 1B in parking the target parking position based on the detected relative positional relationship. FIG. 3 is a schematic diagram illustrating an example of the third parking assistance function for the first vehicle 1A. In the case of the second vehicle 1B, the terms "host vehicle 1A," "first parking assistance device 10A," and "external sensor 11A" in the following description are replaced with "other vehicle 1B," "second parking assistance device 10B," and "external sensor 11B." When parking assistance control using the third parking assistance function is initiated, the first parking assistance device 10A uses the external sensor 11A to find an available vacant space 41 around the first vehicle 1A and set it as the target parking position. For example, the parking assistance device 10 may find the vacant space 41 based on the detection results of parking frame lines 40 indicating the parking space. Further, for example, the first parking assistance device 10A may detect parked vehicles as objects around the host vehicle 1A and find the spaces between the parked vehicles as the vacant spaces 41.

[0023] The first parking assistance device 10A detects the relative position of a target parking position (vacant space) 41 with respect to a current position 33 of the host vehicle 1A using a sensor mounted on the host vehicle 1A, and calculates a target parking path 34 from the current position 33 of the host vehicle 1A to the target parking position 41. The first parking assistance device 10A may detect an obstacle O2 around the target parking position 41 using an external sensor 11A. The first parking assistance device 10A may calculate the target parking path 34 so as to avoid the obstacle O2. The parking assistance device 10A performs parking assistance control of the host vehicle 1A based on the calculated target parking path 34. In addition, the third parking assistance function may be a function (FAP: Full Auto Parking) that automatically controls all of the steering angle, driving force, and braking force of the vehicle 1A so that the vehicle 1A travels along a target driving route from the current position of the vehicle 1A to the target parking position 41, or a function (IPA: Intelligent Parking Assist) in which the user operates the accelerator pedal and brake pedal and the first parking assistance device 10A automatically controls only the steering angle.

[0024] Referring to FIG. 1 , when the host vehicle 1A has a first parking assist function and the other vehicle 1B has a second parking assist function, parking assist information generated by the host vehicle 1A and stored (registered) in the first parking assist device 10A can be provided to the other vehicle 1B to assist the other vehicle 1B in parking by using a candidate parking position where the host vehicle 1A has previously parked as a target parking position. This improves the convenience of the parking assist function. However, if vehicles other than the host vehicle 1A are allowed to use the host vehicle 1A's parking assist information without restriction, there is a risk that the privacy of the user of the host vehicle 1A may be violated. For example, if a partial image including image feature points of a learned target captured by the first camera of the host vehicle 1A is used as feature data for the parking assist information, transmitting feature data including an image containing personal information of the user of the host vehicle 1A (e.g., an image of a wall, nameplate, or surrounding objects on the user's private property) to the other vehicle 1B may result in a risk of violating the privacy of the user of the host vehicle 1A.

[0025] Therefore, in the parking assistance method of the embodiment, when the other vehicle 1B requests parking assistance information, the safety level of transmitting the parking assistance information from the own vehicle 1A to the other vehicle 1B (or the reliability of the other vehicle 1B) is determined, and if the safety level is equal to or higher than a first threshold value Th1, the parking assistance information is transmitted from the own vehicle 1A to the other vehicle 1B. As a result, if the safety level of transmitting the parking assistance information from the own vehicle 1A to the other vehicle 1B is low, the transmission of parking assistance information that may include personal information of the user of the own vehicle 1A is suppressed, thereby preventing the privacy of the user of the own vehicle 1A from being compromised.

[0026] The parking assistance method of the embodiment will be described in detail below. FIG. 4 is a flowchart of an example of the parking assistance method of the embodiment. In step S1, the controller 15A of the host vehicle 1A determines whether the other vehicle 1B has requested that parking assistance information stored in the storage device 18A of the host vehicle 1A be transmitted to the other vehicle 1B. For example, the controller 15B of the other vehicle 1B may request the host vehicle 1A to transmit parking assistance information by transmitting a parking assistance information request signal requesting transmission of parking assistance information to the host vehicle 1A via the communication devices 13A and 13B. If parking assistance information has not been requested (step S1: N), the process ends. If parking assistance information has been requested (step S1: Y), the process proceeds to step S2.

[0027] In step S2, the controller 15A executes a safety level determination process. In the safety level determination process, the controller 15A determines whether the safety level SL of transmitting parking assist information from the host vehicle 1A to the other vehicle 1B is equal to or greater than a first threshold value Th1 (SL≧Th1), equal to or greater than a second threshold value Th2 that is lower than the first threshold value Th1 and less than the first threshold value Th1 (Th1>SL≧TL2), equal to or greater than a third threshold value Th3 that is lower than the second threshold value Th2 and less than the second threshold value Th2 (Th2>SL≧TL3), or less than the third threshold value Th3 (Th3>SL).

[0028] 5 is a flowchart of an example of the safety level determination process. In step S20, the controller 15A determines whether the user of the host vehicle 1A has consented to the sharing of the parking assistance information registered in the storage device 18A by the host vehicle 1A with unspecified vehicles other than the host vehicle 1A. For example, the controller 15A may receive, from the user of the host vehicle 1A, first consent setting information, which is setting information for selecting whether or not to consent to the sharing of the parking assistance information with unspecified vehicles other than the host vehicle 1A, and determine whether or not the user has consented to the sharing of the parking assistance information with unspecified vehicles based on the first consent setting information. The controller 15A may receive the first consent setting information from the user when the controller 15A receives a parking assistance information request signal from the other vehicle 1B, or may receive the first consent setting information from the user in advance and store it in the storage device 18A.

[0029] If the sharing of parking assistance information with unspecified vehicles is permitted (step S20: Y), the process proceeds to step S22. If the sharing of parking assistance information with unspecified vehicles is not permitted (step S20: N), the process proceeds to step S21. In step S21, the controller 15A determines that the safety level SL is less than the third threshold value Th3. The safety level determination process then ends.

[0030] In step S22, the controller 15A determines whether the user of the host vehicle 1A has consented to the sharing of the parking assist information registered in the storage device 18A by the host vehicle 1A with the other vehicle 1B that transmitted the parking assist information request signal. For example, the controller 15A may receive, from the user of the host vehicle 1A, second consent setting information, which is setting information for selecting whether to consent to the sharing of the parking assist information with a specific other vehicle 1B, and determine whether the user has consented to the sharing of the parking assist information with the other vehicle 1B based on the second consent setting information. For example, the controller 15A may receive the second consent setting information from the user at the time when the controller 15A receives the parking assist information request signal from the other vehicle 1B.

[0031] If the sharing of parking assistance information with the other vehicle 1B has not been approved (step S22: N), the process proceeds to step S21. If the sharing of parking assistance information with the other vehicle 1B has been approved (step S22: Y), the process proceeds to step S23. In the flowchart of FIG. 5 , if the sharing of parking assistance information with unspecified vehicles other than the subject vehicle 1A has not been consented to, or if the sharing of parking assistance information with specific other vehicle 1B has not been consented to, the safety level SL is determined to be less than the third threshold value Th3, and if the sharing of parking assistance information with unspecified vehicles other than the subject vehicle 1A has been consented to and the sharing of parking assistance information with specific other vehicle 1B has been consented to, the processing proceeds to step S23. However, instead of this, the safety level determination processing may be modified so that if the sharing of parking assistance information with unspecified vehicles other than the subject vehicle 1A has not been consented to and the sharing of parking assistance information with specific other vehicle 1B has not been consented to, the safety level SL is determined to be less than the third threshold value Th3, and if the sharing of parking assistance information with unspecified vehicles other than the subject vehicle 1A has been consented to or if the sharing of parking assistance information with specific other vehicle 1B has been consented to, the processing proceeds to step S23.

[0032] In step S23, the controller 15A determines whether the distance between the host vehicle 1A and the other vehicle 1B is equal to or less than a predetermined distance threshold. For example, the controller 15A may detect the current position of the other vehicle 1B and calculate the distance to the other vehicle 1B by performing image recognition processing based on an image of the other vehicle 1B captured by the first camera of the external environment sensor 11A. The controller 15A may also receive information on the current position of the other vehicle 1B measured by the positioning device 14B via the communication devices 13A and 13B. If the distance between the host vehicle 1A and the other vehicle 1B is equal to or less than the predetermined distance threshold (step S23: Y), the process proceeds to step S25. If the distance between the host vehicle 1A and the other vehicle 1B is greater than the predetermined distance threshold (step S23: N), the process proceeds to step S24. In step S24, the controller 15A determines that the safety level SL is equal to or greater than the third threshold Th3 and less than the second threshold Th2. The determination process then ends.

[0033] In step S25, the controller 15A determines whether the other vehicle 1B that transmitted the parking assistance information request signal is registered in advance in the storage device 18A as a vehicle with which the parking assistance information registered by the host vehicle 1A can be shared in the storage device 18A. For example, the controller 15A may receive an operation from the user of the host vehicle 1A to input a vehicle with which the parking assistance information registered in the storage device 18A by the host vehicle 1A can be shared, and register the input vehicle identification information in the storage device 18A. The controller 15A may acquire the identification information of the other vehicle 1B when receiving a parking assistance information request signal from the other vehicle 1B. For example, the controller 15A may detect the vehicle identification information (e.g., a license plate number) by image recognition processing based on an image of the other vehicle 1B captured by the first camera of the external sensor 11A, and may receive the vehicle identification information from the controller 15B of the other vehicle 1B via the communication devices 13A and 13B. The controller 15A may determine whether the other vehicle 1B is a specific vehicle pre-registered in the memory device 18A by comparing the identification information registered in the memory device 18A with the identification information of the other vehicle 1B.

[0034] If the other vehicle 1B is not a pre-registered vehicle (step S25: N), the process proceeds to step S27. If the other vehicle 1B is a pre-registered vehicle (step S25: Y), the process proceeds to step S26. In step S26, the controller 15A determines that the safety level SL is equal to or greater than the first threshold value Th1. The safety level determination process then ends.

[0035] In step S27, the controller 15A determines whether the candidate parking position is privately owned (such as the home or workplace of the user of the vehicle 1A). If the candidate parking position is not privately owned (step S27: N), the process proceeds to step S26. If the candidate parking position is privately owned (step S27: Y), the process proceeds to step S28. In step S28, the controller 15A determines that the safety level SL is equal to or greater than the second threshold value Th2 and less than the first threshold value Th1. The safety level determination process then ends.

[0036] 4. In step S3, the controller 15A determines whether the safety level SL is equal to or greater than the first threshold value Th1. If the safety level SL is not equal to or greater than the first threshold value Th1 (step S3: N), the process proceeds to step S5. If the safety level SL is equal to or greater than the first threshold value Th1 (step S3: Y), the process proceeds to step S4. In step S4, the controller 15A reads out the parking assistance information registered in the storage device 18A by the host vehicle 1A. The controller 15A transmits to the other vehicle 1B the parking assistance information read out from the storage device 18A and a storage permission signal that permits the other vehicle 1B to store the parking assistance information received from the host vehicle 1A in the storage device 18B of the other vehicle 1B.

[0037] The controller 15B of the other vehicle 1B assists the other vehicle 1B in parking the target parking position using the second parking assist function based on the parking assist information received from the host vehicle 1A. Specifically, the controller 15B extracts surrounding targets around the other vehicle 1B using the vehicle sensor 12B. The controller 15B matches the learned targets included in the parking assist information with the surrounding targets and associates identical feature points with each other. The controller 15B calculates the relative position of the candidate parking position with respect to the other vehicle 1B based on the relative positional relationship between the surrounding targets and the other vehicle 1B and the relative positional relationship between the learned targets associated with the surrounding targets and the candidate parking position.

[0038] The controller 15B sets the candidate parking position as the target parking position, and calculates a target parking path from the current position of the other vehicle 1B to the target parking position based on the relative positions of the candidate parking positions with respect to the other vehicle 1B. The controller 15B performs parking assistance control for the other vehicle 1B based on the calculated target parking path. When the controller 15B receives a storage permission signal permitting storage of the parking assistance information, the controller 15B stores the parking assistance information in the storage device 18B. This makes it possible to provide assistance using the second parking assistance function by using the parking assistance information received from the host vehicle 1A when parking the other vehicle 1B again in the same target parking position where it was parked this time. The processing then ends.

[0039] In step S5, the controller 15A determines whether the safety level SL is equal to or greater than the second threshold value Th2. If the safety level SL is not equal to or greater than the second threshold value Th2 (step S5: N), the process proceeds to step S8. If not (step S5: Y), the process proceeds to step S6. In step S6, the controller 15A limits the partial image to a portion including image feature points of the learned target included in the parking assistance information. For example, the controller 15A may mask or delete a portion of the partial image including personal information of the user of the vehicle 1A or image feature points that are not relevant to control by the first parking assistance function or the second parking assistance function (e.g., a portion that is not relevant to matching the feature points of the learned target with the feature points of the surrounding targets), so as to limit the partial image to a portion related to matching the feature points of the learned target with the feature points of the surrounding targets.

[0040] In step S7, the controller 15A transmits to the other vehicle 1B the parking assistance information after some of the image feature points have been processed, and a storage prohibition signal prohibiting the storage of the parking assistance information received from the host vehicle 1A in the storage device 18B of the other vehicle 1B. The controller 15B of the other vehicle 1B assists the other vehicle 1B in parking the other vehicle 1B at the target parking position using the second parking assistance function based on the parking assistance information received from the host vehicle 1A. When the controller 15B receives the storage prohibition signal prohibiting the storage of the parking assistance information, once the parking assistance control of the other vehicle 1B is completed (when the other vehicle 1B is parked at the target parking position), the controller 15B discards the parking assistance information without storing it in the storage device 18B. As a result, the other vehicle 1B temporarily shares the parking assistance information with the host vehicle 1A only during this parking assistance control. The processing then ends.

[0041] In step S8, the controller 15A determines whether the safety level SL is equal to or greater than the third threshold value Th3. If the safety level SL is equal to or greater than the third threshold value Th3 (step S8: Y), the process proceeds to step S9. In step S9, the controller 15A generates map data representing the relative positional relationship between the position of the other vehicle 1B and the candidate parking positions. An example of the map data generation process will be described below with reference to FIGS. 6(a) to 6(c). The controller 15A generates map data when both the host vehicle 1A and the other vehicle 1B are located near the candidate parking position 31, as shown in FIG. 6(a). For example, the controller 15A may generate map data when both the target objects around the candidate parking position 31 and the other vehicle 1B are within a range detectable by the external sensor 11A of the host vehicle 1A. In FIGS. 6(a) and 6(b), the position of the host vehicle 1A is denoted as "P1," and in FIGS. 6(a) and 6(c), the position of the other vehicle 1B is denoted as "P2."

[0042] The storage device 18A of the host vehicle 1A stores parking assistance information related to the candidate parking position 31. The parking assistance information may include feature amount data representing the feature amounts of the learned target (circle plot) and relative position data representing the relative positional relationship between the candidate parking position 31 and the learned target. For example, the feature amount data may be a partial image including image feature points of the learned target captured by the first camera of the host vehicle 1A. For example, the relative position data may be the relative position coordinates of the learned target in a coordinate system based on the candidate parking position 31, or may include position information of the learned target and the candidate parking position 31 in a map coordinate system based on a fixed point.

[0043] The parking assistance information may include information specifying the parking direction (i.e., the forward / backward direction of the vehicle 1 when parked in the target parking position 31) in which the vehicle 1 is parked at the candidate parking position 31. If the relative position data is coordinate information on a coordinate system with the candidate parking position 31 as the reference position, the information specifying the parking direction may be omitted by specifying one of the horizontal coordinate axes, the X-axis or the Y-axis, as the parking direction. The parking assistance information may also include obstacle data indicating the relative positional relationship between the candidate parking position 31 and an obstacle O1 around the candidate parking position 31.

[0044] When generating map data from the parking assistance information, the controller 15A uses the external sensor 11A to detect the relative positional relationship between the host vehicle 1A and targets around the host vehicle 1A. In the following description, targets around the host vehicle 1A detected when generating the map data may be referred to as "detected targets." The controller 15A matches the learned targets with the detected targets to associate identical feature points. Then, based on the relative positional relationship between the detected targets and the host vehicle 1A and the relative positional relationship between the learned targets associated with the detected targets and the candidate parking positions 31, the position information of the candidate parking positions 31 in the parking assistance information is converted into coordinates in a coordinate system based on the current position P1 of the host vehicle 1A (hereinafter referred to as the "first vehicle coordinate system").

[0045] For example, the controller 15A may calculate an affine transformation matrix that converts the coordinate positions of the relative position data of the parking assistance information into coordinate positions on the first vehicle coordinate system based on the relative positional relationship between the detected target and the host vehicle 1A and the relative positional relationship between the learned target associated with the detected target and the candidate parking position 31. The controller 15A may convert the position information of the learned target and the obstacle O1, in addition to the candidate parking position 31, into coordinates on the first vehicle coordinate system. Figure 6(b) shows intermediate map data including the position information of the candidate parking position 31, the learned target, and the obstacle O1 converted into coordinates on the first vehicle coordinate system.

[0046] Next, the controller 15A detects the current position P2 and the longitudinal direction of the other vehicle 1B. For example, the controller 15A may detect the current position P2 and the longitudinal direction of the other vehicle 1B by image recognition processing based on an image of the other vehicle 1B captured by the first camera of the external sensor 11A. The controller 15A may also receive information on the current position and longitudinal direction of the other vehicle 1B measured by the positioning device 14B via the communication devices 13A and 13B. The controller 15A generates map data by converting the position information of the intermediate map data ( FIG. 6( b) ), which is coordinate information in the host vehicle coordinate system, into coordinates in a coordinate system (hereinafter referred to as the “other vehicle coordinate system”) based on the current position P2 of the other vehicle 1B. FIG. 6( c) shows map data including the position information of the candidate parking position 31, the learned target object, and the obstacle O1 converted into coordinates in the other vehicle coordinate system. The map data may include position information of the candidate parking positions 31, the learned targets, and the obstacles O1 in the other vehicle coordinate system, and feature data of the learned targets. As in step S6, the controller 15A may process a part of the partial image including the image feature points of the learned targets included in the map data.

[0047] In step S10, the controller 15A transmits the generated map data to the other vehicle 1B. The second parking assistance device 10B receives the map data via the communication device 13B. From the received map data, the controller 15B extracts the relative positional relationship of the candidate parking position 31 with respect to the current position of the other vehicle 1B and the direction (parking direction) in which the vehicle will be parked at the candidate parking position 31. Based on the extracted relative positional relationship and parking direction, the controller 15B assists the other vehicle 1B in parking at the candidate parking position 31 using the third parking assistance function.

[0048] Specifically, the controller 15B calculates a target parking path from the current position P2 of the other vehicle 1B to the candidate parking position 31. The controller 15B may calculate the target parking path from the current position P2 to the candidate parking position 31 while avoiding the obstacle O1. The controller 15B performs parking assist control of the other vehicle 1B based on the calculated target parking path 34. The processing then ends. On the other hand, if the safety level SL is less than the third threshold value Th3 (step S8: N), the controller 15A prohibits the transmission of parking assist information and map data to the other vehicle 1B (does not transmit parking assist information and map data to the other vehicle 1B). The processing then ends.

[0049] Effects of the Embodiments (1) In the parking assistance method, based on parking assistance information including information on candidate parking positions stored in association with position information of known targets around the host vehicle and position information of targets detected around the host vehicle by a sensor mounted on the host vehicle, the controller sets the candidate parking position corresponding to the position information of the detected targets as the target parking position of the host vehicle, thereby causing the controller to realize a first parking assistance function that assists the host vehicle in parking at the target parking position. The controller determines whether another vehicle around the host vehicle has requested transmission of parking assistance information, determines the safety level of transmitting the parking assistance information from the host vehicle to the other vehicle, and transmits the parking assistance information from the host vehicle to the other vehicle if the safety level is equal to or greater than a first threshold and the other vehicle has requested transmission of the parking assistance information. This improves the convenience of the parking assistance function because the parking assistance information created by the host vehicle can be used to assist the parking of the other vehicle. Meanwhile, because the parking assistance information is shared only if the safety level is equal to or greater than the first threshold, the privacy of the user of the host vehicle is prevented from being compromised.

[0050] (2) When the safety level is less than the first threshold and equal to or greater than a second threshold that is lower than the first threshold, the controller may permit other vehicles to use the parking assistance information only temporarily. This prevents other vehicles from parking in a parking space used by the host vehicle due to the parking assistance information being used unintentionally by the user of the host vehicle. (3) When the safety level is less than the first threshold and equal to or greater than a second threshold that is lower than the first threshold, the controller may transmit to the other vehicle a portion of image information of known targets included in the parking assistance information as information of known targets. This prevents leakage of parking assistance information containing personal information when the safety level is less than the first threshold.

[0051] (4) When the safety level is less than the second threshold and equal to or greater than a third threshold lower than the second threshold, the controller may generate map information indicating the relative positional relationship between the position information of the other vehicle detected by the host vehicle and the target parking position, and transmit the map information from the host vehicle to the other vehicle instead of the parking assistance information. This allows the other vehicle to use the minimum information required for the parking assistance function even when the safety level is relatively low. (5) When the safety level is less than the third threshold, the controller may prohibit the host vehicle from transmitting the parking assistance information to the other vehicle. This prevents the sharing of parking assistance information when the minimum safety level cannot be guaranteed.

[0052] (6) The controller may determine the safety level based on whether the user of the host vehicle 1 has agreed to share the parking assistance information with unspecified vehicles. This makes it possible to restrict the sharing of parking assistance information with other vehicles when the user of the host vehicle 1 does not want to share the parking assistance information with unspecified vehicles. (7) The controller may determine the safety level based on whether the user of the host vehicle has agreed to share the parking assistance information with other vehicles when the other vehicle requests the parking assistance information. This makes it possible to restrict the sharing of parking assistance information with other vehicles when the user of the host vehicle does not want to share the parking assistance information with specific other vehicles.

[0053] (8) The controller may determine the safety level based on the distance between the host vehicle and another vehicle. This makes it possible to prevent the parking assistance information from being shared with an unintended vehicle. (9) The controller may determine the safety level based on whether the target parking position is on private property. This makes it possible to restrict the sharing of parking assistance information depending on whether the target parking position is on private property. (10) The controller may determine the safety level based on whether the other vehicle is a registered vehicle that has been registered in advance with the host vehicle. This makes it possible to share parking assistance information with other users (family members, acquaintances, etc.) who are known in advance to use the same parking space as the parking space where the host vehicle is to be parked.

[0054] All examples and conditional terms described herein are intended for educational purposes to aid the reader in understanding the present invention and the concepts provided by the inventor for the advancement of technology, and should be construed without limitation to the specifically described examples and conditions above, and the configuration of examples herein for illustrating the advantages and disadvantages of the present invention. Although the embodiments of the present invention have been described in detail, it should be understood that various changes, substitutions, and alterations can be made thereto without departing from the spirit and scope of the present invention.

[0055] DESCRIPTION OF SYMBOLS 1A...first vehicle, 1B...second vehicle, 10A...first parking assistance device, 10B...second parking assistance device, 11A, 11B...external sensor, 12A, 12B...vehicle sensor, 13A, 13B...communication device, 14A, 14B...positioning device, 15A, 15B...controller, 16A, 16B...actuator (ACTR), 17A, 17B...processor, 18A, 18B...storage device, 100...parking assistance system

Claims

1. A parking assistance method for causing a controller to realize a first parking assistance function that sets a candidate parking position corresponding to the position information of a target object detected around the host vehicle as a target parking position of the host vehicle, based on parking assistance information including information on candidate parking positions stored in association with position information of known targets around the host vehicle, and position information of targets detected around the host vehicle by a sensor mounted on the host vehicle, and assists the host vehicle in parking at the target parking position, The controller determining whether or not another vehicle present around the host vehicle has requested transmission of the parking assistance information; determining a degree of safety of transmitting the parking assistance information from the host vehicle to the other vehicle; When the safety level is equal to or greater than a first threshold and the other vehicle requests transmission of the parking assistance information, the host vehicle transmits the parking assistance information to the other vehicle. A parking assistance method comprising:

2. The parking assistance method according to claim 1, wherein when the safety level is less than the first threshold and equal to or greater than a second threshold that is lower than the first threshold, the parking assistance information is only permitted to be used temporarily by the other vehicle.

2. The parking assistance method according to claim 1, wherein, when the safety level is less than the first threshold value and is equal to or greater than a second threshold value that is lower than the first threshold value, a part of image information of the known object included in the parking assistance information is transmitted to the other vehicle as information of the known object.

4. The parking assistance method according to claim 2, wherein when the safety level is less than the second threshold and equal to or greater than a third threshold that is lower than the second threshold, map information is generated that represents a relative positional relationship between the position information of the other vehicle detected by the host vehicle and the target parking position, and the map information is transmitted from the host vehicle to the other vehicle in place of the parking assistance information.

5. The parking assistance method according to claim 4, wherein when the safety level is less than the third threshold value, transmission of the parking assistance information from the host vehicle to the other vehicle is prohibited. 　 The parking assistance method according to any one of claims 1 to 5, characterized in that the safety level is determined based on whether or not a user of the vehicle has agreed to sharing the parking assistance information with unspecified vehicles. 　 The parking assistance method according to any one of claims 1 to 6, characterized in that the safety level is determined based on whether or not a user of the vehicle has agreed to sharing the parking assistance information with the other vehicle at the time the other vehicle requests the parking assistance information.

8. The parking assistance method according to claim 1, wherein the safety level is determined based on a distance between the host vehicle and the other vehicle.

9. The parking assistance method according to claim 1, wherein the safety level is determined based on whether the target parking position is on private property or not. 　 The parking assistance method according to any one of claims 1 to 9, characterized in that the safety level is determined based on whether the other vehicle is a registered vehicle that has been registered in advance with the subject vehicle. 　 A parking assistance device having a first parking assistance function that sets a candidate parking position corresponding to the position information of a target object detected around the vehicle as a target parking position of the vehicle based on parking assistance information including information on candidate parking positions stored in association with position information of known targets around the vehicle and position information of targets detected around the vehicle, and assists in parking the vehicle at the target parking position, a sensor mounted on the host vehicle to detect targets present around the host vehicle; a communication device having a function of communicating with other vehicles present around the vehicle; a controller that executes a process of determining whether the other vehicle has requested transmission of the parking assistance information, a process of determining a safety level of transmitting the parking assistance information from the host vehicle to the other vehicle, and a process of transmitting the parking assistance information from the host vehicle to the other vehicle via the communication device when the safety level is equal to or greater than a first threshold value and transmission of the parking assistance information has been requested by the other vehicle; A parking assistance device comprising: 　 a first parking assistance device having a first parking assistance function that sets a candidate parking position corresponding to the position information of a target object detected around the first vehicle as a target parking position of the first vehicle based on parking assistance information including information on candidate parking positions stored in association with position information of known targets around the first vehicle and position information of targets detected around the first vehicle by a sensor mounted on the first vehicle, and assists in parking the first vehicle at the target parking position; a second parking assist device having a second parking assist function that sets a candidate parking position corresponding to the position information of a target object detected around the second vehicle by a sensor mounted on the second vehicle as a target parking position of the second vehicle based on the parking assist information and position information of the detected target object, and assists in parking the second vehicle at the target parking position, the first parking assistance device determines a safety level of transmitting the parking assistance information from the first vehicle to the second vehicle, and when the safety level is equal to or greater than a first threshold value and transmission of the parking assistance information is requested by the second vehicle, transmits the parking assistance information from the first vehicle to the second vehicle; The second parking assistance device receives the parking assistance information from the first parking assistance device, and based on the received parking assistance information and position information of a target object detected around the second vehicle by a sensor mounted on the second vehicle, sets a candidate parking position corresponding to the position information of the detected target object as a target parking position of the second vehicle, thereby assisting the second vehicle in parking at the target parking position. A parking assistance system characterized by:

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