JP7673699B2 - Driving Support Devices - Google Patents

Description

This disclosure relates to a driving assistance device.

Patent No. 4483764 is known as a technical document related to driving assistance devices. Patent No. 4483764 discloses a technology for ensuring the visibility of traffic signals, which encourages the driver to maintain the required distance when the distance between vehicles detected by a vehicle distance detection device is less than the required distance required for the driver to keep the traffic signal within the driver's field of vision.

Patent No. 4483764

However, the above-mentioned conventional technologies ensure visibility based only on the environment outside the vehicle, and do not sufficiently consider the environment inside the vehicle, which affects the driver's viewing angle, so there are cases where visibility of traffic signals is insufficient.

The present disclosure aims to provide a driving assistance device that can calculate the visibility distance between the vehicle and a traffic light to ensure visibility of the traffic light.

The driving assistance device disclosed herein is a driving assistance device for ensuring the driver's visibility of traffic lights based on the height of a traffic light ahead of the vehicle, and includes a viewpoint position estimation unit that estimates the driver's viewpoint position based on an image captured by a driver monitor camera or the seat position of the driver's seat, an angle estimation unit that estimates the sun visor angle based on the detection result of an angle sensor of the driver's sun visor, a visual angle calculation unit that calculates the driver's visual angle relative to the upper front of the vehicle based on the visual angle and the sun visor angle, and a visibility distance calculation unit that calculates the distance between the vehicle and the traffic light, which is the visibility distance for the driver to see the traffic light, based on the visual angle and the height of the traffic light.

This disclosure makes it possible to provide a driving assistance device that can calculate the visibility distance between the vehicle and a traffic light to ensure visibility of the traffic light.

1 is a block diagram showing a driving assistance device according to an embodiment; 1A is a diagram for explaining a visibility distance between a vehicle and a traffic light to ensure visibility of the traffic light, and FIG. 1B is a diagram showing a case where a preceding vehicle is present between the vehicle and the traffic light. 4 is a flowchart showing driving assistance control.

Embodiments of the present disclosure will be described below with reference to the drawings.

As shown in FIG. 1, the driving assistance device 1 includes a driver monitor camera 2, a driver sun visor angle sensor 3, a seat position sensor 4, a traffic light information receiver 5, a forward sensor 6, a drive actuator 7, a brake actuator 8, an HMI [Human Machine Interface] 9, and an ECU [Electronic Control Unit] 10. The driving assistance device 1 is mounted on the driver's own vehicle, such as a passenger car. The driving assistance device 1 performs driving assistance to ensure the driver's visibility of traffic lights based on the height of the traffic lights ahead of the vehicle.

The driver monitor camera 2 is a camera for capturing an image of the driver. The driver monitor camera 2 is mounted, for example, on the cover of the steering column in front of the driver, and captures an image of the driver's head, including the face. The driver monitor camera 2 transmits information about the image of the driver to the ECU 10.

The angle sensor 3 is provided on the rotation axis of the sun visor for the driver. The sun visor is located inside the body of the vehicle, above and in front of the driver's seat. The sun visor can rotate around an axis that is parallel to the left-right direction of the vehicle 20, for example. The angle sensor 3 detects the rotation angle of the rotation axis as the sun visor angle. The angle sensor 3 transmits information on the sun visor angle to the ECU 10.

The seat position sensor 4 detects the seat position of the driver's seat. The seat position of the driver's seat includes, for example, the seat height and the angle of the backrest. The seat position sensor 4 transmits information about the seat position of the driver's seat to the ECU 10.

The traffic light information receiver 5 performs road-to-vehicle communication between the vehicle and a roadside transmitter and receiver (e.g., an optical beacon) installed on the road. The traffic light information receiver 5 acquires various types of traffic information from TSPS [Traffic Signal Prediction Systems] and the like through road-to-vehicle communication with the roadside transmitter and receiver. The traffic light information receiver 5 acquires display cycle information of traffic lights located on the path of the vehicle. Traffic light display cycle information is information regarding the timing at which a traffic light changes from green to yellow to red.

The traffic light information receiving unit 5 may obtain information about the height of traffic lights located on the path of the vehicle through road-to-vehicle communication. The height of the traffic lights may be obtained by a forward sensor 6, which will be described later. The height of the traffic lights may be obtained from map information if the vehicle's position is recognized. The height of the traffic lights may be a fixed value. The traffic light information receiving unit 5 transmits various pieces of traffic light information obtained through road-to-vehicle communication to the ECU 10.

The forward sensor 6 is a detection device that includes at least one of a camera and a radar sensor, and detects the situation ahead of the vehicle. The camera is an imaging device that captures an image ahead of the vehicle. The camera transmits information about the captured image to the ECU 10. Objects ahead of the vehicle are detected by image recognition processing of the image captured by the camera. The radar sensor detects objects ahead of the vehicle using radio waves (e.g., millimeter waves) or light. The radar sensor detects objects by transmitting radio waves or light ahead of the vehicle and receiving the radio waves or light reflected by the object. The radar sensor transmits information about the detected object to the ECU 10.

The drive actuator 7 controls the drive force of the vehicle's power source in response to a control signal from the ECU 10. The brake actuator 8 controls the braking force of the vehicle's brake system in response to a control signal from the ECU 10. The HMI 9 is an interface for inputting and outputting information between the driving assistance device 1 and the driver. The HMI 9 includes, for example, a display, a speaker, etc. The HMI 9 outputs images from the display and sounds from the speaker in response to a control signal from the ECU 10.

The ECU 10 is an electronic control unit having a CPU [Central Processing Unit] and a storage unit such as a ROM [Read Only Memory] or a RAM [Random Access Memory]. The ECU 10 realizes various functions, for example, by having the CPU execute programs stored in the storage unit.

The functional configuration of the ECU 10 will be described. The ECU 10 includes a viewpoint position estimation unit 11, an angle estimation unit 12, a visual angle calculation unit 13, a visible distance calculation unit 14, a vehicle height estimation unit 15, a distance setting unit 16, and an execution unit 17.

The viewpoint position estimation unit 11 estimates the viewpoint position of the driver based on the image captured by the driver monitor camera 2. The viewpoint position estimation unit 11 estimates the viewpoint position of the driver using well-known image processing methods such as edge extraction, noise removal, pattern matching, deep learning, etc. Here, FIG. 2(a) is a diagram for explaining the visibility distance between the vehicle and a traffic light to ensure the visibility of the traffic light. As shown in FIG. 2(a), the driver's viewpoint position 22 is located inside the body 21 of the vehicle 20. The driver's viewpoint position 22 is the position of the driver's eyes in the vertical direction and in the forward and backward directions of the vehicle 20.

The angle estimation unit 12 estimates the sun visor angle based on the detection result of the angle sensor 3. The sun visor angle is, for example, the angle that the surface of the sun visor 23 facing the driver makes with respect to the horizontal plane.

The visual angle calculation unit 13 calculates the visual angle V of the driver relative to the upper front of the vehicle 20 based on the driver's viewpoint position 22 and the sun visor angle. The visual angle calculation unit 13 calculates the bottom end position (position in the vertical direction and position in the front-rear direction) of the sun visor 23 based on pre-stored information on the mounting position of the sun visor 23, pre-stored information on the shape of the sun visor 23 (including size information), and the sun visor angle. The visual angle calculation unit 13 calculates the visual angle V of the driver based on the driver's viewpoint position 22 and the bottom end position of the sun visor 23. The visual angle V is, for example, the angle formed by a straight line passing through the driver's viewpoint position 22 and the bottom end position of the sun visor 23 in a side view of the vehicle 20 with respect to the front-rear direction.

The visibility distance calculation unit 14 calculates the visibility distance for the driver to see the traffic light 30 based on the viewing angle V and the height H of the traffic light 30. When there is no preceding vehicle ahead of the vehicle 20, the visibility distance calculation unit 14 calculates the horizontal distance D1 between the vehicle 20 and the traffic light 30 when the traffic light 30 is located on a straight line passing through the driver's viewpoint position 22 and the bottom end position of the sun visor 23 as the visibility distance.

Next, calculation of the visibility distance when a preceding vehicle is present between the host vehicle 20 and the traffic light 30 will be described. FIG. 2(b) is a diagram showing a case where a preceding vehicle is present between the host vehicle 20 and the traffic light 30. As shown in FIG. 2(b), a preceding vehicle 40 is present in front of the host vehicle 20 and in front of the traffic light 30. The vehicle height estimation unit 15 estimates the vehicle height of the preceding vehicle 40 based on the detection result of the forward sensor 6.

The visibility distance calculation unit 14 calculates the horizontal distance D2 between the vehicle 20 and the traffic light 30 at which the driver can see the traffic light 30 based on the viewing angle V, the height H of the preceding vehicle 40, the height of the preceding vehicle 40, and the distance between the vehicle 20 and the preceding vehicle 40, as the visibility distance. The visibility distance at which the driver can see the traffic light 30 is calculated, for example, geometrically. In the situation shown in FIG. 2(b), the horizontal distance D2 is greater than the horizontal distance D1. When there is a possibility that the preceding vehicle 40 may obstruct the driver's view of the traffic light 30, the visibility distance calculation unit 14 may calculate a relatively large visibility distance with a margin of error.

The distance setting unit 16 sets a target distance to the traffic light 30 for the vehicle 20. The distance setting unit 16 determines whether the visibility distance is greater than a preset distance. The preset distance is, for example, a distance preset by the driver. If the visibility distance is greater than the preset distance, the distance setting unit 16 sets the visibility distance as the target distance. If the visibility distance is equal to or less than the preset distance, the distance setting unit 16 sets the preset distance as the target distance.

The execution unit 17 executes driving assistance. When the visibility distance is set as the target distance, the execution unit 17 outputs to the HMI 9 that the visibility distance (target distance) is greater than the preset distance. This makes it possible to suppress inadvertent accelerator operation by the driver. The execution unit 17 controls the drive actuator 7 or the brake actuator 8 to control the host vehicle 20 so that the horizontal distance between the host vehicle 20 and the traffic light 30 becomes the target distance. When the traffic light 30 is displaying red, the execution unit 17 stops the host vehicle 20 at the target position. When the traffic light 30 is displaying green, the execution unit 17 does not need to execute driving assistance.

Next, the processing of the ECU 10 will be described. As shown in FIG. 3, in step S1, the ECU 10 estimates the driver's viewpoint position and the sun visor angle. In step S2, the ECU 10 calculates the driver's viewing angle V. In step S3, the ECU 10 calculates the visibility distance. In step S4, the ECU 10 determines whether the visibility distance is greater than a preset distance. If the ECU 10 determines that the visibility distance is greater than the preset distance (step S4: YES), the ECU 10 proceeds to step S5. In step S5, the ECU 10 sets the visibility distance as a target distance.

In step S6, the ECU 10 notifies the HMI 9 that the visible distance (target distance) is greater than the preset distance. In step S7, the ECU 10 controls the host vehicle 20 so that the distance between the host vehicle 20 and the traffic light 30 becomes the target distance.

If the ECU 10 determines that the visible distance is equal to or less than the preset distance (step S4: NO), the ECU 10 proceeds to step S8. In step S8, the ECU 10 sets the preset distance as the target distance. After step S8, the ECU 10 proceeds to step S7.

As described above, in the driving assistance device 1, the viewpoint position estimation unit 11 estimates the viewpoint position of the driver based on the image captured by the driver monitor camera 2, and the angle estimation unit 12 estimates the sun visor angle based on the detection result of the angle sensor 3 of the sun visor 23 for the driver. Then, the visual angle calculation unit 13 calculates the visual angle V of the driver with respect to the upper front of the vehicle 20 based on the viewpoint position and the sun visor angle. As a result, the visual angle calculation unit 13 can accurately calculate the visual angle V of the driver based on the in-vehicle environment (sun visor angle) that affects the visual angle V of the driver compared to the case where the sun visor angle is not taken into account. The visual angle calculation unit 13 can calculate the visual angle V of the driver even if the sun visor angle changes, for example. Therefore, the visual distance calculation unit 14 can accurately calculate the visual distance for the driver to view the traffic light 30 based on the accurate visual angle V and the height H of the traffic light 30 compared to the case where the sun visor angle is not taken into account. Therefore, the driving assistance device 1 can calculate the visibility distance to ensure the visibility of the traffic light 30.

Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments. The present disclosure can be implemented in various forms, including the above-described embodiments, with various modifications and improvements based on the knowledge of those skilled in the art.

The viewpoint position estimation unit 11 may estimate the viewpoint position of the driver based on the seat position of the driver's seat. In this case, the viewpoint position estimation unit 11 assumes that the driver's seat height is a predetermined value and estimates the viewpoint position of the driver based on the height of the seat surface of the driver's seat and the angle of the backrest, etc. The viewpoint position estimation unit 11 may estimate the viewpoint position of the driver based on at least one of the image captured by the driver monitor camera 2 and the seat position of the driver's seat.

When the sun visor 23 is imaged by the driver monitor camera 2, the angle estimation unit 12 may estimate the sun visor angle based on the image captured by the driver monitor camera 2. The angle estimation unit 12 may estimate the sun visor angle by using a known image processing method such as edge extraction, noise removal, pattern matching, deep learning, etc. The driving assistance device 1 may not be provided with a vehicle height estimation unit 15.

When there is no preceding vehicle ahead of the host vehicle 20 and the visibility distance is greater than the distance between the stop line and the traffic light 30, the execution unit 17 may stop the host vehicle 20 at a position a predetermined distance away from the stop line (a position not exceeding the stop line). Even in this case, the execution unit 17 may output to the HMI 9 that the visibility distance is greater than the distance between the stop line and the traffic light 30. When there is a preceding vehicle 40 ahead of the host vehicle 20, the execution unit 17 may control the inter-vehicle distance between the host vehicle 20 and the preceding vehicle 40 so that the distance between the host vehicle 20 and the traffic light 30 becomes the target distance. The execution unit 17 may be configured to only have a function of providing the driver with information regarding the visibility distance without controlling the vehicle speed of the host vehicle 20. The driving assistance device 1 may not be provided with the execution unit 17. The driving assistance device 1 may simply transmit information regarding the visibility distance to the driver's user terminal (including a wearable device).

1...driving assistance device, 2...driver monitor camera, 3...angle sensor, 11...viewpoint position estimation unit, 12...angle estimation unit, 13...viewpoint calculation unit, 14...visibility distance calculation unit, 20...own vehicle, 22...viewpoint position, 23...sun visor, 30...traffic signal, V...viewpoint.

Claims (1)

A driving assistance device for ensuring visibility of a traffic signal by a driver based on a height of the traffic signal ahead of a vehicle, comprising:
a viewpoint position estimation unit that estimates a viewpoint position of the driver based on an image captured by a driver monitor camera or a seat position of the driver's seat;
an angle estimation unit that estimates a sun visor angle based on a detection result of an angle sensor of the driver's sun visor;
a visual angle calculation unit that calculates a visual angle of the driver with respect to an upper front direction of the vehicle based on the viewpoint position and the sun visor angle;
a visibility distance calculation unit that calculates a visibility distance between the vehicle and the traffic light, which is the distance required for the driver to see the traffic light, based on the viewing angle and the height of the traffic light.

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