Driving assistance device and driving assistance method

Abstract

A driving assistance device performs driving assistance of a vehicle when a predetermined target exists in a driving assistance area set in front of the vehicle. The driving assistance device is configured so as to be able to change the setting of the area of the driving assistance area, and to change the setting of the area of the driving assistance area in the expansion direction when a pedestrian crosswalk is detected in front of the vehicle. The area of the driving assistance region is expanded so as to expand in the outside direction of the vehicle so as to include the entire driving assistance region when the pedestrian crosswalk is detected.

Description

Technical Field

[0001] The present invention relates to a driving assistance device and a driving assistance method. Background Art

[0002] Japanese Patent Application Laid-Open No. 2009-271766 discloses a conventional obstacle detection device that, when a crosswalk exists within an obstacle detection area set in front of a vehicle, deforms the shape of the obstacle detection area to conform to the crosswalk. Specifically, in this conventional obstacle detection device, when a crosswalk exists within the obstacle detection area set in front of the vehicle, the left and right widths of the obstacle detection area on the crosswalk are expanded to match the left and right widths of the crosswalk. Summary of the Invention

[0003] However, since there are multiple white lines extending in the front-to-back direction at regular intervals on a crosswalk, the multiple white lines and the silhouettes of pedestrians are mixed together. Therefore, pedestrian detection is relatively difficult on a crosswalk, resulting in a possible delay in pedestrian detection.

[0004] The present invention has been made in view of such a problem, and an object of the present invention is to suppress a delay in detecting a predetermined target object ahead of a vehicle.

[0005] In order to solve the above-mentioned problem, a driving assistance device according to a certain technical solution of the present invention, which implements driving assistance of the vehicle when a predetermined target object exists in a driving assistance area set in front of the vehicle, is constructed to be able to change the setting of the area of the driving assistance area. When the area of the driving assistance area when a crosswalk is detected in front of the vehicle can be changed in an expanding direction, the area of the driving assistance area is expanded in a manner that expands toward the outside of the vehicle in a manner that includes the entire area of the driving assistance area when a crosswalk is detected.

[0006] In addition, in a driving assistance method of a certain technical solution of the present invention, which implements driving assistance for the vehicle when a predetermined target object exists in a driving assistance area set in front of the vehicle, the setting of the area of the driving assistance area can be changed. When the area of the driving assistance area when a crosswalk is detected in front of the vehicle can be changed in an expanding direction, the area of the driving assistance area is expanded in a manner that expands outward from the vehicle in a manner that includes the entire area of the driving assistance area when a crosswalk is detected.

[0007] According to these aspects of the present invention, since the driving assistance area is expanded when a crosswalk is detected, it is possible to suppress a delay in detecting a predetermined target object. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0009] Figure 1 This is a schematic diagram of the configuration of a driving assistance device according to one embodiment of the present invention.

[0010] Figure 2A This is a diagram showing an example of a driving assistance area set on the right front side of the vehicle.

[0011] Figure 2B This is a diagram showing an example of a driving assistance area set on the left front side of the vehicle.

[0012] Figure 3 This is a flowchart illustrating setting control of the driving assistance zone according to one embodiment of the present invention. DETAILED DESCRIPTION

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same components are denoted by the same reference numerals.

[0014] Figure 1 1 is a schematic diagram of the configuration of a driving assistance device 100 according to an embodiment of the present invention.

[0015] Driving assistance device 100 includes peripheral sensors 1, vehicle sensors 2, an HMI (Human Machine Interface) 3, an actuator 4, and a control device 5. Peripheral sensors 1, vehicle sensors 2, HMI 3, actuator 4, and control device 5 are communicatively connected to each other via an in-vehicle network 7 compliant with a standard such as a controller area network.

[0016] The surrounding sensor 1 is a sensor for generating surrounding data representing the conditions surrounding a vehicle (hereinafter referred to as the "own vehicle") for which driving assistance is being provided by the driving assistance device 100. In this embodiment, the surrounding sensor 1 includes one or more external cameras 11 for capturing images of the surroundings of the own vehicle, including the area in front of the own vehicle.

[0017] The exterior camera 11 captures the surroundings of the vehicle at a predetermined frame rate (e.g., 10 Hz to 40 Hz) to generate a surrounding image showing the surroundings of the vehicle. Each time the exterior camera 11 generates a surrounding image, it transmits the generated surrounding image to the control device 5 as surrounding data.

[0018] Alternatively, instead of or in addition to the external camera 11, a distance measuring sensor for measuring the distance to objects such as vehicles and pedestrians around the vehicle may be provided as the surrounding sensor 1. Examples of distance measuring sensors include a laser radar (LiDAR) that emits laser light and measures distance based on its reflected light, and a millimeter wave radar sensor that emits radio waves and measures distance based on their reflected waves.

[0019] The vehicle sensor 2 is a sensor for generating vehicle data indicating the status of the vehicle. In this embodiment, the vehicle sensor 2 includes a speed sensor 21 that generates speed data indicating the vehicle's travel speed, and a positioning sensor 22 that generates current position data indicating the vehicle's current position, such as latitude and longitude. However, the vehicle sensor 2 is not limited to these sensors. The vehicle sensor 2 transmits the acquired data to the control device 5 as vehicle data.

[0020] The HMI 3 is a user interface for exchanging information between the vehicle and its occupants. The HMI 3 includes an output device 31 for notifying the vehicle occupants through their physical senses (e.g., vision, hearing, and touch), and an input device 32 for the occupants to input and respond to input operations. In this embodiment, the output device 31 includes a display (e.g., an instrument display, a center display, a heads-up display, etc.) 311 and a speaker 312, while the input device 32 includes a touch panel 321 and a microphone 322.

[0021] The HMI 3 displays information (e.g., text information, image information) corresponding to the display signal received from the control device 5 on the display 311 and outputs sound corresponding to the sound signal from the speaker 312. Furthermore, the HMI 3 transmits data (hereinafter referred to as "occupant input data") input by the vehicle occupant through the input device 32 via the panel or voice input to the control device 5.

[0022] The HMI 3 can be a device pre-installed in the vehicle itself or a terminal such as a smartphone owned by a vehicle occupant. In the latter case, information can be exchanged, for example, by short-range wireless communication between the vehicle itself and the vehicle occupant's terminal, or by communication between the vehicle occupant's terminal and an external server (not shown), with information exchanged indirectly via the server.

[0023] The actuator 4 is a device used to control the driving of the vehicle. In this embodiment, the actuator 4 includes an acceleration actuator 41 (e.g., at least one of an engine and a motor) for controlling the acceleration of the vehicle, a brake actuator 42 (e.g., a hydraulic actuator) for controlling the braking of the vehicle, and a steering actuator 43 (e.g., a steering motor) for controlling the steering of the vehicle.

[0024] The control device 5 is an ECU (Electronic Control Unit) including a communication unit 51 , a storage unit 52 , and a processing unit 53 .

[0025] The communication unit 51 includes an interface circuit for connecting the control device 5 to the in-vehicle network 7. The communication unit 51 provides various data received from the sensors 1 and 2, the HMI 3, etc. to the processing unit 53. The communication unit 51 also outputs various signals output from the processing unit 53 to the HMI 3, the actuator 4, etc.

[0026] The storage unit 52 includes a storage medium such as a HDD (Hard Disk Drive), an SSD (Solid Disk Drive), or a semiconductor memory, and stores various computer programs and data used for processing in the processing unit 53 .

[0027] The processing unit 53 has one or more CPUs (Central Processing Units) and their peripheral circuits, and executes various computer programs stored in the storage unit 52. The processing unit 53 is, for example, a processor. The processing unit 53 may also have other arithmetic circuits such as a logical operation unit, a numerical operation unit, or a graphics processing unit. The processing unit 53 functions as a ground object (ground object) detection unit 61, a target object detection unit 62, and a driving assistance unit 63 by executing processing according to the computer program, and works as a functional unit (module) that realizes predetermined functions. In the following description, when the processing is described with each functional unit 61 to 63 as the subject, it means that the processing unit 53 is executing the program that realizes each functional unit 61 to 63.

[0028] Hereinafter, the content of the specific processing performed by the control device 5 will be described. Specifically, the content of each functional unit 61 to 63 realized by the processing unit 53 executing the processing according to the program will be described.

[0029] The object detection unit 61 detects objects (ground objects) based on the surrounding data received from the surrounding sensor 1. In the present embodiment, the object detection unit 61 detects the crosswalk ahead based on the surrounding image received from the external camera 11. The object detection unit 61 can detect the crosswalk ahead based on the surrounding image received from the external camera 11 using, for example, image recognition methods such as graphic matching and semantic segmentation. When a crosswalk is detected, the object detection unit 61 detects crosswalk data related to the crosswalk. The crosswalk data includes, for example, the distance to the crosswalk. The distance to the crosswalk can be detected based on, for example, the distance of the Y coordinate (vertical coordinate) on the surrounding image where the crosswalk is detected, or the size of the crosswalk area extracted from the surrounding image by image recognition.

[0030] Furthermore, the feature detection unit 61 can detect a pedestrian crossing ahead by, for example, inputting surrounding images received from the external camera 11 into a recognizer pre-trained to detect pedestrian crossings. The method for detecting a pedestrian crossing is not particularly limited, and various known methods may be used.

[0031] The target object detection unit 62 detects targets existing around the vehicle based on the surrounding data received from the surrounding sensor 1. The target object detection unit 62 detects areas in the surrounding images where targets such as vehicles, two-wheeled vehicles, pedestrians, traffic lights, and buildings are displayed, and the types of targets displayed in the areas, by, for example, sequentially inputting the surrounding images received from the external camera 11 into the recognizer. The recognizer can be, for example, a convolutional neural network (CNN) having a plurality of convolutional layers connected in series from the input side to the output side. The target object detection unit 62 uses the standard size of the target stored in the storage unit 52 for each type of target and the size of the target detected in the surrounding image to estimate the distance from the external camera 11 to the target, and calculates the position and speed of the target by tracking (tracing) the target detected in the surrounding image in a time series. In addition, the target detection method is not limited to this method, and detection can be performed by various well-known methods.

[0032] The driving assistance unit 63 is in a driving assistance area set in front of the own vehicle (see Figure 2A and Figure 2B) When a predetermined target object exists, driving assistance is provided to the driver of the own vehicle. The predetermined target object is a moving object such as a pedestrian or a two-wheeled vehicle that is moving in the direction of the own vehicle and that may be traveling on the crosswalk. As driving assistance to the driver, for example, the driving assistance unit 63 can implement notifications such as attention-calling notifications and deceleration urging notifications through the HMI3. In addition, as driving assistance to the driver, for example, the driving assistance unit 63 can also implement driving control of the own vehicle (for example, deceleration, steering avoidance, etc.) through the actuator 4 in addition to or instead of notifications based on the HMI3.

[0033] Below, refer to Figure 2A and Figure 2B , the driving assistance performed by the driving assistance unit 63 is described in further detail.

[0034] Figure 2A and Figure 2B This is a diagram showing an example of driving assistance areas set on the right front side and the left front side of the vehicle.

[0035] like Figure 2A and Figure 2B As shown, the driving assistance zones set on the right and left front sides of the vehicle are bilaterally symmetrical, and their area can be changed in stages or continuously (gradually or steplessly) according to the driver's preference. In this embodiment, the driving assistance zones can be changed in three stages (levels) from smallest to largest: the first zone, the second zone, and the third zone.

[0036] The first area is a predetermined area on the right and left front sides of the vehicle. The second area is an area that is expanded so as to encompass the entire first area and expand outward from the vehicle. The third area is an area that is expanded so as to encompass the entire second area and expand outward from the vehicle.

[0037] The driving assistance zone is initially set to the third zone, which has the largest area. Increasing the area of the driving assistance zone allows for earlier detection of predetermined objects to the right and left front of the vehicle, but this also increases the frequency of driving assistance intervention. Therefore, some drivers may decide that the driving assistance zone is too large and set it to the second or first zone.

[0038] On the other hand, at a crosswalk, since there are multiple white lines extending in the front-to-back direction at intervals, the multiple white lines and the silhouettes of pedestrians are mixed together. Therefore, pedestrian detection is relatively difficult in a crosswalk, resulting in the possibility of delayed pedestrian detection.

[0039] Therefore, when there is a crosswalk ahead, it is desirable to detect pedestrians as early as possible. Therefore, in this embodiment, if the driving assistance area is not the third area when a crosswalk is detected ahead, the driving assistance area is temporarily changed to the third area.

[0040] Figure 3 This is a flowchart illustrating the setting control of the driving assistance area according to the present embodiment, which is performed by the driving assistance unit 63 and the control device 5. The control device 5 repeatedly executes this routine at a predetermined calculation cycle ΔT.

[0041] In step S1, the control device 5 determines whether there is a crosswalk ahead based on the detection results of the feature detection unit 61. If there is a crosswalk ahead, the control device 5 proceeds to step S2. On the other hand, if there is no crosswalk ahead, the control device 5 ends this process.

[0042] In step S2, the control device 5 determines whether the pedestrian crossing ahead is a pedestrian crossing without a signal. If the pedestrian crossing ahead is a pedestrian crossing without a signal, the control device 5 proceeds to step S3. On the other hand, if the pedestrian crossing ahead is a pedestrian crossing with a signal, the control device 5 proceeds to step S4.

[0043] Whether the pedestrian crossing ahead is a pedestrian crossing without a signal can be determined based on, for example, the pedestrian crossing detection results of the feature detection unit 61 and the signal detection results of the object detection unit 62. In this embodiment, if the object detection unit 62 does not detect a signal within a predetermined distance before or after the pedestrian crossing detected by the feature detection unit 61, the control device 5 determines that the pedestrian crossing is a pedestrian crossing without a signal.

[0044] Furthermore, in this embodiment, the determination of whether a crosswalk is equipped with a signal is based on the following reasons. This is because collision accidents with moving objects on crosswalks are particularly likely to occur on crosswalks without signals. Expanding the driving assistance zone against the driver's will on crosswalks equipped with signals could increase the frequency of unnecessary driving assistance interventions, such as responding to pedestrians waiting at traffic lights and implementing driving assistance. This could lead to drivers becoming annoyed with the driving assistance.

[0045] In step S3, if the driving assistance zone is not set to the third zone, the control device 5 temporarily expands the driving assistance zone. In this embodiment, the control device 5 temporarily changes the driving assistance zone to the third zone. The temporarily changed driving assistance zone returns to the original zone, for example, when the vehicle passes the crosswalk.

[0046] In step S4 , the control device 5 maintains the driving assistance area at the currently set area.

[0047] The driving assistance device 100 of the present embodiment described above provides driving assistance for the vehicle when a predetermined target object is present in a driving assistance zone set in front of the vehicle. The driving assistance device is configured to be able to change the area of the driving assistance zone. When the area of the driving assistance zone is set to be larger when a crosswalk is detected in front of the vehicle, the area of the driving assistance zone is expanded outward from the vehicle to encompass the entire area of the driving assistance zone when a crosswalk is detected. The predetermined target object is, for example, a moving object capable of traveling on a crosswalk, such as a pedestrian moving toward the vehicle.

[0048] In this way, since the driving assistance area is expanded when a crosswalk is detected in front of the vehicle, it is possible to suppress the occurrence of delays in detecting the specific target object for driving assistance. As a result, it is also possible to suppress the occurrence of delays in the activation timing of driving assistance.

[0049] In particular, in this embodiment, the area of the driving assistance zone is expanded outward from the vehicle to encompass the entire area of the driving assistance zone when a crosswalk is detected. This allows, for example, the driver to capture a specific object, such as a pedestrian traveling on the sidewalk outside of a crosswalk on the roadway, within the driving assistance zone. This specific object, in other words, the specific object that is about to travel across the crosswalk, within the vehicle's lane. In this case, detection of the specific object is no longer required at the crosswalk, thus minimizing any reduction in detection accuracy. Consequently, delays in detecting the specific object can be minimized.

[0050] Furthermore, the driving assistance device 100 of this embodiment is configured to expand the area of the driving assistance area to the maximum settable area when the area of the driving assistance area when a crosswalk is detected in front of the vehicle is not the maximum settable area.

[0051] As a result, when a crosswalk is detected ahead, the driving assistance area can be expanded to the maximum extent, thereby suppressing a delay in detecting a specific target object that is the target of driving assistance.

[0052] Furthermore, in this embodiment, the crosswalks targeted for driving assistance are those without traffic lights. This can prevent unnecessary driving assistance, such as responding to pedestrians waiting at traffic lights. This can also help prevent drivers from becoming annoyed by the driving assistance.

[0053] While the embodiments of the present invention have been described above, the above embodiments merely illustrate a part of application examples of the present invention and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

[0054] For example, in the above embodiment, the driving assistance area is expanded to the third area which is the largest area when a crosswalk is detected ahead. However, the area may be expanded compared to when a crosswalk is detected ahead without being expanded to the largest area.

[0055] Furthermore, for example, in the above-described embodiment, the computer program executed in the control device 5 may be provided in the form of being recorded on a computer-readable removable recording medium such as a semiconductor memory, a magnetic recording medium, or an optical recording medium.

Claims

1. A driving assistance device that provides driving assistance for a vehicle when a predetermined target object is present in a driving assistance area set in front of the vehicle. The driving assistance device is configured as follows: The area of the driving assistance area can be changed. In a case where the area of the driving assistance zone when a crosswalk is detected in front of the vehicle can be set and changed in an expanding direction, the area of the driving assistance zone is expanded in a manner that expands outward from the vehicle in a manner that includes the entire area of the driving assistance zone when the crosswalk is detected.

2. The driving assistance device according to claim 1, The driving assistance device is configured to expand the area of the driving assistance area to the maximum settable area when the area of the driving assistance area when a crosswalk is detected in front of the vehicle is not the maximum settable area.

3. The driving assistance device according to claim 1 or 2, The pedestrian crossing is a pedestrian crossing without a signal light.

4. The driving assistance device according to claim 1 or 2, The predetermined target object is a movable body that is moving toward the vehicle and is capable of traveling on a crosswalk.

5. A driving assistance method for performing driving assistance on a vehicle when a predetermined target object exists in a driving assistance area set in front of the vehicle. In the driving assistance method, The area of the driving assistance area can be changed. In a case where the area of the driving assistance zone when a crosswalk is detected in front of the vehicle can be changed in an expanding direction, the area of the driving assistance zone is expanded in a manner that expands outward from the vehicle in a manner that includes the entire area of the driving assistance zone when the crosswalk is detected.

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