Notification device, notification method, and notification program

Abstract

To notify a driver of a start of a preceding vehicle according to a state of the driver.SOLUTION: A notification device for notifying a driver of an own vehicle of a start of a preceding vehicle stopped in front of the own vehicle includes: a determination section 332 for determining whether the driver is visually recognizing a front side; a state detection section 334 for detecting a state of the preceding vehicle; and a notification section 336 for notifying the driver of the start of the preceding vehicle. The notification section changes a notification form of the start of the preceding vehicle to the driver, based on the state of the preceding vehicle detected by the state detection section, between a case where it is determined that the driver is visually recognizing the front side and a case where it is determined that the driver is not visually recognizing the front side. The notification form includes at least one of notification timing, presence / absence of notification, and a notification method.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to a notification device, a notification method, and a notification program.

Background Art

[0002] There has conventionally been known a vehicle-to-vehicle distance warning device that transmits ultrasonic waves toward a preceding vehicle during traffic congestion and parking, captures the reflected waves that have been reflected, detects that the preceding vehicle has started moving and the vehicle-to-vehicle distance from the own vehicle has reached a predetermined distance, and notifies the driver (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the device described in Patent Document 1, a notification to the driver is made uniformly when the vehicle-to-vehicle distance reaches a predetermined distance regardless of the driver's state. Therefore, if this predetermined distance is set long, there is a possibility that the notification to the driver may be delayed when the driver is distracted or dozing off and does not recognize the start of the preceding vehicle. On the other hand, if this predetermined distance is set short, there is a possibility that a notification may be given to the driver even though the driver is paying attention to the front and recognizes the start of the preceding vehicle, but the driver's operation is slightly delayed.

[0005] In view of the above problems, an object of the present disclosure is to be able to notify the driver of the start of the preceding vehicle according to the driver's state.

Means for Solving the Problems

[0006] The gist of the present disclosure is as follows.

[0007] (1) A notification device that notifies a driver of a host vehicle of the start of a preceding vehicle stopped in front of the host vehicle, comprising: a determination unit that determines whether the driver is visually recognizing the front; a state detection unit that detects the state of the preceding vehicle; a notification unit that notifies the driver of the start of the preceding vehicle, and the notification unit changes the notification form of the start of the preceding vehicle to the driver based on the state of the preceding vehicle detected by the state detection unit when it is determined that the driver is visually recognizing the front and when it is determined that the driver is not visually recognizing the front, wherein the notification form includes at least any one of a notification timing, a presence or absence of notification, and a notification method, the notification device (2) The notification device according to (1) above, wherein when it is determined that the driver is not visually recognizing the front, the notification unit notifies the driver of the start of the preceding vehicle at a timing earlier than when it is determined that the driver is visually recognizing the front after the preceding vehicle starts. (3) The notification device according to (2) above, wherein when it is determined that the driver is visually recognizing the front, the notification unit notifies the driver of the start of the preceding vehicle when the moving amount of the started preceding vehicle becomes equal to or more than a first moving amount, and when it is determined that the driver is not visually recognizing the front, the notification unit notifies the driver of the start of the preceding vehicle when the moving amount of the started preceding vehicle becomes equal to or more than a second moving amount less than the first moving amount. (4) The notification device according to (2) above, wherein when it is determined that the driver is visually recognizing the front, the notification unit notifies the driver of the start of the preceding vehicle when the elapsed time after the preceding vehicle starts becomes equal to or more than a first time, and when it is determined that the driver is not visually recognizing the front, the notification unit notifies the driver of the start of the preceding vehicle when the elapsed time after the preceding vehicle starts becomes equal to or more than a second time less than the first time. (5) When it is determined that the driver is visually recognizing the front, the notification unit notifies the driver of the start of the preceding vehicle when the distance from the host vehicle to the preceding vehicle becomes equal to or greater than a first distance, and when it is determined that the driver is not visually recognizing the front, the notification unit notifies the driver of the start of the preceding vehicle when the distance from the host vehicle to the preceding vehicle becomes equal to or greater than a second distance that is less than the first distance. The notification device according to (2) above. (6) When it is determined by the determination unit that the driver is visually recognizing the front, the notification unit does not notify the driver of the start of the preceding vehicle even if the state detection unit detects that the preceding vehicle has started. The notification device according to (1) above. (7) A notification method performed by a processor of a host vehicle for notifying a driver of a host vehicle of the start of a preceding vehicle stopped in front of the host vehicle, determining whether the driver is visually recognizing the front, detecting the state of the preceding vehicle, and notifying the driver of the start of the preceding vehicle, and when notifying the driver of the start of the preceding vehicle, the form of notifying the driver of the start of the preceding vehicle based on the state of the preceding vehicle is changed depending on whether it is determined that the driver is visually recognizing the front or not visually recognizing the front, The notification form includes at least one of the timing of notification, the presence or absence of notification, and the notification method. A notification method. (8) A notification program for notifying a driver of a host vehicle of the start of a preceding vehicle stopped in front of the host vehicle, determining whether the driver is visually recognizing the front, detecting the state of the preceding vehicle, notifying the driver of the start of the preceding vehicle, causing a computer to execute, When notifying the driver of the start of the preceding vehicle, the notification form of the start of the preceding vehicle to the driver based on the state of the preceding vehicle is changed depending on whether it is determined that the driver is visually recognizing the front or not visually recognizing the front. The notification form includes a notification program including at least any one of the timing of notification, the presence or absence of notification, and the notification method.

Advantages of the Invention

[0008] According to the present disclosure, it is possible to notify the driver of the start of the preceding vehicle according to the state of the driver.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0010] Hereinafter, embodiments will be described in detail with reference to the drawings. In the following description, the same reference numerals are given to similar components.

[0011] First Embodiment <Configuration of the Notification System> Referring to FIGS. 1 to 3, the configuration of a notification system 1 including a notification device according to one embodiment will be described. The notification device notifies the driver of the vehicle (own vehicle) 100 of the start of a preceding vehicle stopped ahead of the own vehicle. FIG. 1 is a schematic block diagram showing the configuration of the notification system 1. FIG. 2 is a schematic side view partially showing the interior of the vehicle 100 equipped with the notification system 1.

[0012] The notification system 1 is mounted on the vehicle 100 and notifies the driver of the vehicle 100 of the start of a preceding vehicle. As shown in FIG. 2, the vehicle 100 includes a steering wheel 102 attached via a steering column 101 and a driver's seat 103 on which the driver sits.

[0013] As shown in FIG. 1, in the present embodiment, the notification system 1 includes a driver monitor camera 11, an outside vehicle camera 12, a distance measuring sensor 13, a human machine interface (HMI) 15, and an electronic control unit (hereinafter referred to as "ECU") 30. The driver monitor camera 11, the outside vehicle camera 12, the distance measuring sensor 13, the HMI 15, and the ECU 30 are communicably connected via, for example, an in-vehicle network 21. The in-vehicle network 21 is a network compliant with a standard such as CAN (Controller Area Network), for example.

[0014] The driver monitor camera 11 captures an image of the driver's face. In the present embodiment, the driver monitor camera 11 is provided above the steering column 101 and is arranged to face the driver so as to be able to capture the driver, specifically, a part of the driver's face and upper body. Note that the driver monitor camera 11 may be provided at a position different from above the steering column 101 as long as it can capture the driver of the vehicle 100. For example, the driver monitor camera 11 may be provided on the steering wheel 102, rearview mirror, meter panel, meter hood, etc. of the vehicle 100.

[0015] The driver monitoring camera 11 includes a camera and a projector. For example, the camera is a CMOS (Complementary Metal Oxide Semiconductor) camera or a CCD (Charge Coupled Device) camera, and the projector is an LED (Light Emitting Diode). Also, in order to be able to image the driver's face without giving discomfort to the driver even in low illuminance situations such as at night, the projector is preferably a near-infrared LED, and it is also preferable that the camera can detect near-infrared rays. For example, the projector is two near-infrared LEDs arranged on both sides of the camera. Also, a filter such as a visible light cut filter may be provided in the camera. The driver monitoring camera 11 outputs the images captured at predetermined intervals to the ECU 30 via the in-vehicle network 21.

[0016] The outside camera 12 is a device that photographs the surroundings of the vehicle. In the present embodiment, the outside camera 12 photographs the front of the vehicle 100. The outside camera 12 is a CMOS camera or a CCD camera that is sensitive to visible light. In the present embodiment, the outside camera 12 is attached, for example, inside the vehicle 100 so as to face the front of the vehicle 100. The outside camera 12 photographs the front area of the vehicle 100 at a predetermined photographing cycle and generates an image in which the front area is shown. Each time the outside camera 12 generates an image, it outputs the generated image to the ECU 30 via the in-vehicle network 21. Note that the outside camera 12 may be a monocular camera or a stereo camera. When a stereo camera is used as the outside camera 12, the outside camera 12 also functions as a distance measuring sensor 13. A plurality of outside cameras with different photographing directions or focal lengths may be provided on the vehicle 100.

[0017] The distance measurement sensor 13 is a sensor that measures the distance to an object existing around the vehicle 100. In particular, in the present embodiment, the distance measurement sensor 13 measures the distance to an object existing in front of the vehicle 100. Further, in the present embodiment, the distance measurement sensor 13 can also measure the azimuth of an object existing around the vehicle 100. The distance measurement sensor 13 is, for example, a radar such as a millimeter-wave radar or a lidar (LIDAR). Furthermore, the distance measurement sensor 13 may be configured to be able to measure the relative speed with an object existing around the vehicle 100. In the present embodiment, the distance measurement sensor 13 measures the distance to an object existing in front of the vehicle. The distance measurement sensor 13 outputs the measurement result of the distance to the surrounding objects to the ECU 30 at a predetermined cycle via the in-vehicle network 21.

[0018] The vehicle sensor 14 is a sensor that detects the state of the vehicle 100. In the present embodiment, the vehicle sensor 14 is a sensor that can be used for detecting or estimating the speed of the vehicle 100. Specifically, the vehicle sensor 14 includes a speed sensor that detects the speed of the vehicle 100 or an acceleration sensor that detects the acceleration of the vehicle 100. The vehicle sensor 14 outputs the detection result of the state of the vehicle 100 to the ECU 30 at a predetermined cycle via the in-vehicle network 21.

[0019] The HMI 15 is an interface for inputting and outputting information between the driver or passenger and the notification system 1. The HMI 15 includes an information providing device for providing various information to the driver or passenger and an input device for the driver or passenger to perform an input operation.

[0020] Specifically, as an information providing device, the HMI 15 includes a display 16 for displaying character information or image information. The display 16 is an example of a display device for displaying images. The display 16 is a display device of any type, such as a liquid crystal display or an organic EL display. The display 16 is arranged such that at least the driver can view its screen. Therefore, the display 16 is arranged, for example, on the instrument panel, meter panel, etc. of the vehicle 100. The display 16 receives an image signal from the ECU 30 via the in-vehicle network 21 and displays an image according to this image signal. Note that the vehicle 100 may include, as an information providing device, another type of display device, such as a head-up display, instead of or in addition to the display 16.

[0021] Also, the HMI 15 has a speaker 17 as an information providing device. The speaker 17 is an example of a device for outputting sound. The speaker 17 receives an audio signal from the ECU 30 via the in-vehicle network 21 and outputs sound according to this audio signal. Note that the HMI 15 may include, as an information providing device, devices other than the display 16 and the speaker 17 (for example, a vibration device, etc.) that provide various information to the driver or passengers.

[0022] In addition, the HMI 15 has a touch panel 18 as an input device. The touch panel 18 is an example of a device for inputting by being touched by the driver or passenger. When the driver or passenger performs an operation by contact, the touch panel 18 outputs an operation signal to the ECU 30 via the in-vehicle network 21. Note that the HMI 15 may include, as an input device, devices other than the touch panel 18 (for example, buttons, switches, etc.) for the driver or passenger to perform input operations.

[0023] <Configuration of the notification device> The ECU 30 functions as a notification device that notifies the driver of the vehicle 100 of the start of the preceding vehicle. Also, the ECU 30 controls the information provided by the information providing device of the HMI 13. Therefore, the ECU 30 controls the image displayed on the display 16 and the sound output from the speaker 17. As shown in FIG. 1, the ECU 30 includes a communication interface 31, a storage unit 32, and a processor 33.

[0024] The communication interface 31 is a circuit for connecting the ECU 30 to the in-vehicle network 21.

[0025] The storage unit 32 stores data. The storage unit 32 has, for example, at least one of a volatile semiconductor memory, a non-volatile semiconductor memory, a hard disk drive (HDD), and a solid state drive (SSD). The storage unit 32 stores a computer program executed by the processor 33 of the ECU 30. Also, the storage unit 32 stores data used in the computer program executed by the processor 33, such as data transmitted from the driver monitoring camera 11 and the like.

[0026] The processor 33 has one or more CPUs (Central Processing Units) and peripheral circuits thereof. The processor 33 may further have other arithmetic circuits such as a logical arithmetic unit or a numerical arithmetic unit. The processor 33 executes the computer program stored in the storage unit 32.

[0027] FIG. 3 is a functional block diagram of the processor 33 of the ECU 30. As shown in FIG. 3, the processor 33 includes an eye opening degree / gaze direction detection unit 331, a determination unit 332, a surrounding recognition unit 333, a preceding vehicle state detection unit 334, a host vehicle state detection unit 335, and a notification unit 336.

[0028] The eye opening degree and line-of-sight direction detection unit 331 detects the driver's eye opening degree and the driver's line-of-sight direction based on the image captured by the driver monitor camera 11. In the present embodiment, the eye opening degree is represented as the distance between the upper and lower eyelids. Also, in the present embodiment, the line-of-sight direction is represented by the horizontal or vertical angle between the longitudinal direction of the vehicle 100 and the driver's line of sight. The eye opening degree and line-of-sight direction detection unit 331 inputs the information on the driver's eye opening degree and line-of-sight direction detected by the eye opening degree and line-of-sight direction detection unit 331 to the determination unit 332.

[0029] The eye opening degree and line-of-sight direction detection unit 331 detects the driver's eye opening degree and line-of-sight direction by any method based on the image captured by the driver monitor camera 11. For example, the eye opening degree and line-of-sight direction detection unit 331 inputs the image obtained from the driver monitor camera 11 to a discriminator that recognizes the upper and lower eyelids, and detects the distance between the recognized upper and lower eyelids as the eye opening degree.

[0030] Also, for example, the eye opening degree and line-of-sight direction detection unit 331 inputs the image obtained from the driver monitor camera 11 to a discriminator that has been pre-trained to identify the positions of the pupil and the corneal reflex of the light source. Then, the eye opening degree and line-of-sight direction detection unit 331 detects the line-of-sight direction based on the positional relationship between the identified pupil and corneal reflex. As such a discriminator, for example, a convolutional neural network (CNN) that outputs the positions of the pupil and corneal reflex when a face image is input is used. Alternatively, the eye opening degree and line-of-sight direction detection unit 331 may input the image obtained from the driver monitor camera 11 to a discriminator that identifies the positions of the inner canthus and iris in the driver's eye. In this case, the eye opening degree and line-of-sight direction detection unit 331 detects the line-of-sight direction based on the positional relationship between the identified inner canthus and iris.

[0031] The determination unit 332 determines whether the driver is visually recognizing the front. In the present embodiment, the determination unit 332 acquires information on the driver's eye opening degree and line-of-sight direction from the eye opening degree and line-of-sight direction detection unit 331, and determines whether the driver is visually recognizing the front based on this information. For example, when the eye opening degree is less than a predetermined threshold value, the determination unit 332 determines that the driver has closed eyes and is not visually recognizing the front. On the other hand, when the eye opening degree is equal to or greater than the predetermined threshold value, for example, when the driver's line-of-sight direction is within a predetermined angle (e.g., 10°) with respect to the longitudinal direction of the vehicle 100 and within a predetermined angle (e.g., 10°) with respect to the horizontal direction (or the direction parallel to the road), the determination unit 332 determines that the driver is visually recognizing the front. On the other hand, when the driver's line-of-sight direction is greater than the above-mentioned predetermined angle with respect to the longitudinal direction of the vehicle 100, or when the driver's line-of-sight direction is greater than the above-mentioned predetermined angle with respect to the horizontal direction (or the direction parallel to the road), the determination unit 332 determines that the driver is not visually recognizing the front. The determination unit 332 inputs the determination result as to whether the driver is visually recognizing the front to the notification unit 336.

[0032] Note that in the present embodiment, the determination unit 332 determines whether the driver is visually recognizing the front based on the driver's eye opening degree and line-of-sight direction. However, the determination unit 332 may determine whether the driver is visually recognizing the front based on parameters other than the driver's eye opening degree and line-of-sight direction. For example, it may be determined whether the driver is visually recognizing the front based on the orientation of the driver's face.

[0033] The surrounding recognition unit 333 recognizes the objects around the vehicle 100 and estimates the relative position of the objects with respect to the vehicle 100 based on the output of the vehicle exterior camera 12 and the output of the distance measurement sensor 13. In particular, in the present embodiment, the surrounding recognition unit 333 recognizes the preceding vehicle located in front of the vehicle 100 and estimates the relative position (relative distance) of the preceding vehicle with respect to the vehicle 100. The surrounding recognition unit 333 inputs the information on the objects around the vehicle 100 to the preceding vehicle state detection unit 334.

[0034] For example, when a lidar is used as the distance measurement sensor 13, the surrounding recognition unit 333 groups the point cloud data output from the lidar for each data having the same distance, and groups the related groups together to perform grouping for each group representing an object. Further, the surrounding recognition unit 333 recognizes an object represented in the image by performing recognition processing on the image captured by the outside vehicle camera 12. Then, the surrounding recognition unit 333 estimates the relative position of the object with respect to the vehicle 100 based on the object group located at the position corresponding to the position of the object in the image recognized by the recognition processing. In particular, the surrounding recognition unit 333 estimates the center position of the object group as the center position of the object. Note that the relative position of the object with respect to the vehicle 100 may be estimated by different methods using the outside vehicle camera 12 and the distance measurement sensor 13. Further, the relative position of the object with respect to the vehicle 100 may be estimated based on only the outside vehicle camera 12, only the distance measurement sensor 13, or sensors different from these.

[0035] The preceding vehicle state detection unit 334 detects the state of the preceding vehicle located in front of the vehicle 100. In the present embodiment, the preceding vehicle state detection unit 334 acquires information on the objects around the vehicle 100 from the surrounding recognition unit 333, and detects the state of the preceding vehicle based on this information. The preceding vehicle state detection unit 334 detects the state of the preceding vehicle based on the information of the preceding vehicle among the object information acquired from the preceding vehicle state detection unit 334. In particular, in the present embodiment, the preceding vehicle state detection unit 334 detects the presence or absence of a preceding vehicle located in front of the vehicle 100 within the same lane as the vehicle 100, the distance and relative speed (or the speed of the preceding vehicle) between the vehicle 100 and the preceding vehicle when the preceding vehicle exists, and the like. The relative speed between the vehicle 100 and the preceding vehicle is detected using this information when the output of the distance measurement sensor 13 includes information on the relative speed with the surrounding objects. On the other hand, when such information is not included in the output of the distance measurement sensor 13, the relative speed between the vehicle 100 and the preceding vehicle is detected based on the time-series relative position of the preceding vehicle. Further, the speed of the preceding vehicle is calculated based on the speed of the vehicle 100 detected by the host vehicle state detection unit 335 described later and the relative speed between the vehicle 100 and the preceding vehicle. The preceding vehicle state detection unit 334 of the vehicle 100 outputs information regarding the state of the preceding vehicle to the notification unit 336.

[0036] The host vehicle state detection unit 335 detects the state of the vehicle 100. In the present embodiment, the host vehicle state detection unit 335 detects the speed of the vehicle 100 based on the output of the vehicle sensor 14. When the vehicle sensor 14 is a speed sensor, the host vehicle state detection unit 335 calculates the speed corresponding to the output of the vehicle sensor 14. The host vehicle state detection unit 335 outputs information on the speed of the vehicle 100 to the notification unit 336.

[0037] The notification unit 336 notifies the driver that the preceding vehicle has started when the preceding vehicle starts from a stopped state. For example, when the preceding vehicle starts from a stopped state, the notification unit 336 causes the display 16 to display that the preceding vehicle has started and causes the speaker 17 to output a voice indicating that the preceding vehicle has started.

[0038] In particular, in the present embodiment, when it is determined in the determination unit 332 that the driver is visually recognizing the front, and when it is determined in the determination unit 332 that the driver is not visually recognizing the front, the form of notification of the start of the preceding vehicle to the driver based on the state of the preceding vehicle detected by the preceding vehicle state detection unit 334 is changed. Here, the form of notification includes at least any one of the timing of notification to the driver, the presence or absence of notification to the driver, and the method of notification to the driver.

[0039] In particular, in the present embodiment, when it is determined in the determination unit 332 that the driver is not visually recognizing the front, the notification unit 336 notifies the driver of the start of the preceding vehicle at an earlier timing after the preceding vehicle has started, compared to when it is determined in the determination unit 332 that the driver is visually recognizing the front. Therefore, in the present embodiment, the notification unit 336 changes the timing of notification to the driver based on whether the driver is visually recognizing the front.

[0040] FIG. 4 is a diagram for explaining the timing of notifying the start of the preceding vehicle P. In FIG. 4, the positional relationship between the vehicle 100 and the preceding vehicle P is shown, and the dashed line in the figure indicates the position where the preceding vehicle P had stopped before starting. In particular, FIG. 4(A) shows the case where the driver is visually recognizing the front, and FIG. 4(B) shows the case where the driver is not visually recognizing the front.

[0041] In the present embodiment, when the stopped preceding vehicle P starts, the notification unit 336 notifies the driver of the start of the preceding vehicle P when the moving amount of the preceding vehicle P after starting becomes equal to or greater than a predetermined reference value. Specifically, the notification unit 336 calculates the moving amount after the stopped preceding vehicle P has started based on the state of the preceding vehicle detected by the preceding vehicle state detection unit 334. Then, the notification unit 336 notifies the driver of the start of the preceding vehicle P when the calculated moving amount becomes equal to or greater than the predetermined reference value.

[0042] In particular, in the present embodiment, as shown in FIG. 4(A), when the driver is visually recognizing the front, the notification unit 336 notifies the driver of the start of the preceding vehicle P when the moving amount of the preceding vehicle P becomes equal to or greater than the first moving amount M1.

[0043] On the other hand, in the present embodiment, as shown in FIG. 4(B), when the driver is not visually recognizing the front, the notification unit 336 notifies the driver of the start of the preceding vehicle P when the moving amount of the preceding vehicle P becomes equal to or greater than the second moving amount M2. Here, the second moving amount M2 is less than the first moving amount. Therefore, in the present embodiment, when the driver is not visually recognizing the front, even if the moving amount of the stopped preceding vehicle P is small, the driver is notified compared to the case where the driver is visually recognizing the front.

[0044] Note that the first moving amount M1 and the second moving amount M2 are predetermined values. However, the first moving amount M1 and the second moving amount M2 may be values that change according to, for example, the brightness outside the vehicle (day or night), etc. However, even in this case, the second moving amount M2 is always set to a value less than the first moving amount.

[0045] As described above, according to the present embodiment, the notification form of the start of the preceding vehicle to the driver is changed based on whether the driver is visually recognizing the front. As a result, the start of the preceding vehicle can be notified to the driver according to the state of the driver. In particular, in the present embodiment, since the driver is notified at an early timing when the driver is not visually recognizing the front, the start of the preceding vehicle can be appropriately notified to the driver according to the state of the driver.

[0046] <Flow of Control> FIG. 5 is a flowchart showing the flow of notification processing performed by the notification device. The illustrated notification processing is executed by the processor 33 of the ECU 30 at regular time intervals.

[0047] As shown in FIG. 5, in the notification process, first, the host vehicle state detection unit 335 detects the state of the vehicle 100 (step S11). In the present embodiment, the host vehicle state detection unit 335 detects the speed of the vehicle 100. Next, the preceding vehicle state detection unit 334 detects the state of the preceding vehicle (step S12). In the present embodiment, the preceding vehicle state detection unit 334 detects, for example, the distance from the preceding vehicle and the speed of the preceding vehicle. Next, the eye opening degree / gaze direction detection unit 331 detects the eye opening degree and gaze direction of the driver (step S13). Note that in this notification process, the detection of the state of the vehicle 100 by the host vehicle state detection unit 335, the detection of the state of the preceding vehicle by the preceding vehicle state detection unit 334, and the detection of the eye opening degree / gaze direction by the eye opening degree / gaze direction detection unit 331 are performed in this order. However, these detections may be performed in any order, or may be performed entirely or partially simultaneously.

[0048] Next, the determination unit 332 determines whether the position of the preceding vehicle has changed while the vehicle 100 is stopped (step S14). Specifically, the determination unit 332 determines that the position of the preceding vehicle has changed while the vehicle 100 is stopped when the speed of the vehicle 100 detected in step S11 is zero and the speed of the preceding vehicle detected in step S12 is not zero. On the other hand, the determination unit 332 determines that the position of the preceding vehicle has not changed while the vehicle 100 is stopped when the speed of the vehicle 100 detected in step S11 is not zero or the speed of the preceding vehicle detected in step S12 is zero. If it is determined in step S14 that the position of the preceding vehicle has not changed while the vehicle 100 is stopped, the notification process ends. Therefore, in this case, the driver is not notified that the preceding vehicle has started. Note that in the present embodiment, in step S14, the determination unit 332 determines whether the position of the preceding vehicle has changed while the vehicle 100 is stopped, but it may also determine only whether the vehicle 100 is stopped.

[0049] In step S14, when it is determined that the position of the preceding vehicle has changed while the vehicle 100 is stopped, the determination unit 332 determines whether the driver is visually recognizing the front (step S15). Whether the driver is visually recognizing the front is determined based on the eye opening degree and the line-of-sight direction detected by the eye opening degree and line-of-sight direction detection unit 331 in step S13.

[0050] In step S15, when it is determined that the driver is visually recognizing the front, the notification unit 336 determines whether the movement amount M of the preceding vehicle after the stopped preceding vehicle starts moving is equal to or greater than the first movement amount M1 (step S16). The movement amount M of the preceding vehicle after the stopped preceding vehicle starts moving is calculated based on the state of the preceding vehicle detected in step S12.

[0051] In step S16, when it is determined that the movement amount M of the preceding vehicle is less than the first movement amount M1, the notification process ends. Therefore, in this case, the driver is not notified that the preceding vehicle has started moving. On the other hand, in step S16, when it is determined that the movement amount M of the preceding vehicle is equal to or greater than the first movement amount M1, the notification unit 336 notifies the driver that the preceding vehicle has started moving (step S17). In the present embodiment, the notification unit 336 causes the display 16 to display that the preceding vehicle has started moving and causes the speaker 17 to output a voice indicating that the preceding vehicle has started moving.

[0052] On the other hand, in step S15, when it is determined that the driver is not visually recognizing the front, the notification unit 336 determines whether the movement amount M of the preceding vehicle after the stopped preceding vehicle starts moving is equal to or greater than the second movement amount M2 (M2 < M1) (step S18). The movement amount M of the preceding vehicle after the stopped preceding vehicle starts moving is calculated based on the state of the preceding vehicle detected in step S12.

[0053] If it is determined in step S18 that the moving amount M of the preceding vehicle is less than the second moving amount M2, the notification process ends. Therefore, in this case, the driver is not notified that the preceding vehicle has started. On the other hand, if it is determined in step S18 that the moving amount M of the preceding vehicle is equal to or greater than the second moving amount M2, the notification unit 336 notifies the driver that the preceding vehicle has started (step S17).

[0054] <Modification Example> In the above embodiment, when the preceding vehicle P that has stopped starts, the notification unit 336 notifies the driver that the preceding vehicle has started when the moving amount of the preceding vehicle after starting becomes equal to or greater than a predetermined reference value.

[0055] However, in one modification example, when the preceding vehicle P that has stopped starts, the notification unit 336 may notify the driver that the preceding vehicle has started when the elapsed time since the preceding vehicle started becomes equal to or greater than a predetermined time. In this case, when it is determined in the determination unit 332 that the driver is visually recognizing the front, the notification unit 336 notifies the driver that the preceding vehicle has started when the elapsed time since the preceding vehicle started becomes equal to or greater than the first time. Further, when it is determined in the determination unit 332 that the driver is not visually recognizing the front, the notification unit 336 notifies the driver that the preceding vehicle has started when the elapsed time since the preceding vehicle started becomes equal to or greater than the second time. Here, the second time is less than the first time. Therefore, also in this modification example, when the driver is not visually recognizing the front, the driver is notified at an earlier timing than when the driver is visually recognizing the front.

[0056] Note that the first time and the second time are predetermined fixed values. However, the first time and the second time may be values that change according to, for example, the brightness outside the vehicle. However, even in this case, the second time is always set to a value less than the first time. Also, the elapsed time may be the elapsed time during the movement of the preceding vehicle. Therefore, the elapsed time may be a time that progresses while the preceding vehicle is moving and stops while the preceding vehicle is stopped.

[0057] Also, in another modification, when the stopped preceding vehicle P starts moving, the notification unit 336 may notify the driver that the preceding vehicle has started moving when the distance from the vehicle 100 to the preceding vehicle becomes equal to or greater than a predetermined reference value. In this case, as shown in FIG. 4, when it is determined in the determination unit 332 that the driver is visually recognizing the front, the notification unit 336 notifies the driver that the preceding vehicle has started moving when the distance from the vehicle 100 to the preceding vehicle becomes equal to or greater than the first distance D1. Further, when it is determined in the determination unit 332 that the driver is not visually recognizing the front, the notification unit 336 notifies the driver that the preceding vehicle has started moving when the distance from the vehicle 100 to the preceding vehicle becomes equal to or greater than the second distance D2. Here, the second distance D2 is less than the first distance D1. Therefore, also in this modification, when the driver is not visually recognizing the front, the notification to the driver is performed at an earlier timing than when the driver is visually recognizing the front.

[0058] Note that the first distance and the second distance are predetermined values. However, the first distance and the second distance may be values that change according to, for example, the brightness outside the vehicle or the like. However, even in this case, the second distance is always set to a value less than the first distance.

[0059] In the above-described embodiment, regardless of whether the driver is looking ahead, the driver is notified of the start of the vehicle ahead by the same notification method. However, depending on whether the driver is looking ahead or not, the driver may be notified of the start of the vehicle ahead by different notification methods. For example, when it is determined that the driver is looking ahead, the notification by the speaker 17 is performed but the notification by the display 16 is not performed, and when it is determined that the driver is not looking ahead, the notification may be performed by both the speaker 17 and the display 16. Alternatively, when it is determined that the driver is looking ahead, the notification by the speaker 17 may be performed at a lower notification volume compared to when it is determined that the driver is not looking ahead. Further, when notifying the driver of the start of the vehicle ahead by different notification methods depending on whether the driver is looking ahead or not, it is not necessary to change the timing of the notification to the driver depending on whether the driver is looking ahead or not.

[0060] Second Embodiment Next, with reference to FIG. 6, the notification device according to the second embodiment will be described. The configuration and control of the notification device according to the second embodiment are basically the same as those of the notification device according to the first embodiment. Hereinafter, among the controls of the notification device according to the second embodiment, the parts different from those of the notification device according to the first embodiment will be mainly described.

[0061] In the above-described first embodiment, regardless of whether the driver is looking ahead, when the preceding vehicle starts moving while the vehicle 100 is stopped, the driver is notified of the start of the preceding vehicle. However, in the second embodiment, when the driver is looking ahead, even if the preceding vehicle starts moving while the vehicle 100 is stopped, the driver is not notified of the start of the preceding vehicle. Therefore, in the present second embodiment, when it is determined in the determination unit 332 that the driver is looking ahead and when it is determined in the determination unit 332 that the driver is not looking ahead, the form of notification of the start of the preceding vehicle to the driver based on the state of the preceding vehicle detected by the preceding vehicle state detection unit 334 (particularly, the presence or absence of notification to the driver) is changed. As a result, even when the driver is looking ahead, the annoyance of being notified of the start of the preceding vehicle is reduced.

[0062] FIG. 6 is a flowchart showing the flow of notification processing performed by the notification device according to the second embodiment. The illustrated notification processing is executed by the processor 33 of the ECU 30 at regular time intervals. Since steps S21 to S24 and S27 in FIG. 6 are the same as steps S11 to S14 and S17 in FIG. 5, respectively, the description thereof is omitted.

[0063] As shown in FIG. 6, in the notification processing according to the second embodiment, when it is determined in step S24 that the position of the preceding vehicle has changed while the vehicle 100 is stopped, the determination unit 332 determines whether the driver is looking ahead (step S25). If it is determined in step S25 that the driver is looking ahead, the notification processing ends. Therefore, in this case, the driver is not notified that the preceding vehicle has started moving.

[0064] On the other hand, if it is determined in step S25 that the driver is not looking ahead, the notification unit 336 determines whether the moving amount M of the preceding vehicle after the stopped preceding vehicle has started moving is equal to or greater than a third moving amount M3 (step S26). The third moving amount M3 may be a predetermined constant value or a value that changes according to the brightness outside the vehicle or the like.

[0065] If it is determined in step S26 that the moving amount M of the preceding vehicle is less than the third moving amount M3, the notification process ends. Therefore, in this case, the driver is not notified that the preceding vehicle has started. On the other hand, if it is determined in step S26 that the moving amount M of the preceding vehicle is equal to or greater than the third moving amount M3, the notification unit 336 notifies the driver that the preceding vehicle has started (step S27).

[0066] As described above, the preferred embodiments according to the present disclosure have been described. However, the present disclosure is not limited to these embodiments, and various modifications and changes can be made within the scope of the claims.

Explanation of Reference Numerals

[0067] 1 Notification system 11 Driver monitoring camera 12 Exterior camera 13 Distance measuring sensor 14 Vehicle sensor 30 ECU 33 Processor

Claims

1. A notification device that notifies a driver of a host vehicle of the start of a preceding vehicle stopped in front of the host vehicle, comprising: a determination unit that determines whether the driver is visually recognizing the front; a state detection unit that detects the state of the preceding vehicle; a notification unit that notifies the driver of the start of the preceding vehicle; and the notification unit changes the notification form of the start of the preceding vehicle to the driver based on the state of the preceding vehicle detected by the state detection unit when it is determined that the driver is visually recognizing the front and when it is determined that the driver is not visually recognizing the front, wherein the notification form includes at least any one of a notification timing, a presence or absence of notification, and a notification method.

2. The notification device according to claim 1, wherein when it is determined that the driver is not visually recognizing the front, the notification unit notifies the driver of the start of the preceding vehicle at a timing earlier than when it is determined that the driver is visually recognizing the front, after the preceding vehicle has started.

3. The notification device according to claim 2, wherein when it is determined that the driver is visually recognizing the front, the notification unit notifies the driver of the start of the preceding vehicle when the moving amount of the started preceding vehicle becomes equal to or greater than a first moving amount, and when it is determined that the driver is not visually recognizing the front, the notification unit notifies the driver of the start of the preceding vehicle when the moving amount of the started preceding vehicle becomes equal to or greater than a second moving amount less than the first moving amount.

4. The notification device according to claim 2, wherein when it is determined that the driver is visually recognizing the front, the notification unit notifies the driver of the start of the preceding vehicle when the elapsed time since the preceding vehicle started becomes equal to or greater than a first time, and when it is determined that the driver is not visually recognizing the front, the notification unit notifies the driver of the start of the preceding vehicle when the elapsed time since the preceding vehicle started becomes equal to or greater than a second time less than the first time.

5. The notification device according to claim 2, wherein when it is determined that the driver is visually recognizing the front, the notification unit notifies the driver of the start of the preceding vehicle when the distance from the host vehicle to the preceding vehicle becomes equal to or greater than a first distance, and when it is determined that the driver is not visually recognizing the front, the notification unit notifies the driver of the start of the preceding vehicle when the distance from the host vehicle to the preceding vehicle becomes equal to or greater than a second distance less than the first distance.

6. The notification unit according to claim 1, wherein when it is determined by the determination unit that the driver is visually recognizing the front, even if it is detected by the state detection unit that the preceding vehicle has started moving, the notification unit does not notify the driver of the start of the preceding vehicle.

7. A notification method performed by a processor of a host vehicle for notifying a driver of the host vehicle of the start of a preceding vehicle stopped in front of the host vehicle, comprising: determining whether the driver is visually recognizing the front; detecting the state of the preceding vehicle; notifying the driver of the start of the preceding vehicle, and when notifying the driver of the start of the preceding vehicle, the notification form of the start of the preceding vehicle to the driver based on the state of the preceding vehicle is changed depending on whether it is determined that the driver is visually recognizing the front or not, wherein the notification form includes at least any one of a notification timing, presence or absence of notification, and a notification method.

8. A notification program for notifying a driver of a host vehicle of the start of a preceding vehicle stopped in front of the host vehicle, comprising: determining whether the driver is visually recognizing the front; detecting the state of the preceding vehicle; notifying the driver of the start of the preceding vehicle, and causing a computer to execute when notifying the driver of the start of the preceding vehicle, the notification form of the start of the preceding vehicle to the driver based on the state of the preceding vehicle is changed depending on whether it is determined that the driver is visually recognizing the front or not, wherein the notification form includes at least any one of a notification timing, presence or absence of notification, and a notification method. ​

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