Driver state estimation device

Abstract

Provided is a driver state estimation device capable of accurately estimating the state of a driver regardless of the traveling environment. A driver state estimation device (100) is provided with an in-vehicle imaging device (32) for detecting the line of sight of a driver, and a controller (10) configured so as to estimate the state of the driver on the basis of the line of sight of the driver, and the controller sets a predetermined visual range including the line of sight direction when the line of sight of the driver is directed in the direction of travel of the vehicle. A distribution of fixation points of the driver within a predetermined time is acquired on the basis of the line of sight of the driver, and when the proportion of fixation points included in a predetermined visual range among all fixation points included in the acquired distribution of fixation points is equal to or greater than a predetermined proportion, it is estimated that the driver is in an abnormal state.

Description

Technical Field

[0001] The present invention relates to a driver state estimating device for estimating the state of a driver driving a vehicle. Background Art

[0002] Previously, a driver status detection device has been proposed for detecting abnormalities in a vehicle driver (e.g., see Patent Document 1). The device described in Patent Document 1 detects the amplitude and frequency of the driver's eye blinks (jumping eye movements in which the driver intentionally shifts their line of sight) and also detects the driver's attention level. While the driver is driving, this attention level increases as the number of areas to be noted in the vehicle's external environment increases. Based on the height of the driver's attention level and the amplitude and frequency of the driver's eye blinks, abnormalities in the driver's condition are detected.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2021-077136

[0006] Technical problem to be solved by the invention

[0007] In driving environments that require rapid and extensive visual search, such as when turning right at an intersection and simultaneously checking for multiple objects of concern, such as vehicles in the oncoming lane or pedestrians crossing a crosswalk, the amplitude of eye blinks increases when the driver is in a normal state. In contrast, when the driver's state is abnormal, such as due to a brain disease, the amplitude of eye blinks does not increase and tends to remain at a low value. Therefore, it is possible to infer whether the driver's state is normal based on the amplitude of eye blinks.

[0008] However, in driving environments where rapid, extensive visual exploration is unnecessary, such as when driving on a highway where there are few other vehicles nearby and few objects to check for attention, the eye blink amplitude does not increase even when the driver's state is normal. Therefore, there is no significant difference in eye blink amplitude between normal and abnormal conditions. In such situations, it is difficult to accurately estimate the driver's state using the aforementioned prior art. In other words, depending on the driving environment, it can sometimes be difficult to accurately estimate the driver's state. Summary of the Invention

[0009] The present invention has been made to solve such a problem, and an object of the present invention is to provide a driver state estimating device capable of accurately estimating the driver's state regardless of the driving environment.

[0010] Technical means for solving technical problems

[0011] In order to solve the above-mentioned technical problems, the present invention is a driver state estimation device for estimating the state of a driver driving a vehicle, comprising: a line of sight detection device for detecting the driver's line of sight; and a controller for estimating the driver's state based on the driver's line of sight. The controller sets a prescribed visual range, and the prescribed visual range includes the direction of sight when the driver directs his line of sight toward the direction of travel of the vehicle. Based on the driver's line of sight, the distribution of the driver's gaze points within a prescribed time is obtained. When the proportion of the gaze points included in the prescribed visual range among all the gaze points included in the obtained distribution of gaze points is greater than a prescribed proportion, it is estimated that the driver is in an abnormal state.

[0012] According to the present invention thus constructed, when the proportion of gaze points included in a prescribed visual range in the direction of sight when the driver directs his or her gaze in the direction of travel of the vehicle, among all the gaze points included in the distribution of the driver's gaze points within a prescribed time, is greater than a prescribed proportion, the controller infers that the driver is in an abnormal state. Therefore, based on the proportion of gaze points included in the prescribed visual range, it can be determined that the driver's tendency to concentrate his or her gaze near the direction of travel has increased due to a certain disease, and regardless of the driving environment, the driver can be correctly inferred to be in an abnormal state.

[0013] In the present invention, preferably, the driver state estimating device further includes a driving environment information acquiring device that acquires driving environment information of the vehicle, and the controller is configured to set the size of the predetermined visual range based on the driving environment information.

[0014] According to the present invention thus constituted, the controller sets the size of the predetermined visual range based on the driving environment information. Therefore, by setting an appropriate size of the predetermined visual range based on the driving environment information, it is possible to more accurately estimate whether the driver's condition is abnormal based on the driving environment.

[0015] In the present invention, it is preferred that the controller is configured to obtain the number of attention objects around the vehicle based on driving environment information, and when the number of attention objects is above a prescribed threshold, the prescribed visual range is set larger than when the number of attention objects is less than the prescribed threshold.

[0016] According to the present invention thus constructed, when the number of attention objects is greater than a prescribed threshold value, the controller sets the prescribed visual range to be larger than when the number of attention objects is less than the prescribed threshold value. Therefore, based on the characteristic that the smaller the number of attention objects is, the stronger the tendency of the driver in an abnormal state to concentrate his or her line of sight near the direction of travel of the vehicle is. The size of the prescribed visual range that is likely to differ from that of a driver in a normal state can be set, and whether the driver's state is abnormal can be more accurately inferred according to the driving environment.

[0017] In the present invention, preferably, the controller is configured to set a circular range centered on an average direction of distribution of gaze directions within a predetermined time as the predetermined visual range based on the driver's gaze.

[0018] According to the present invention thus constructed, the controller sets a circular range centered on the average direction of the distribution of line of sight directions within a specified time as a specified visual range. Therefore, the specified visual range can be set as a basis for estimating the driver's state based on the actual line of sight direction of the driver, and whether the driver's state is abnormal can be more accurately estimated.

[0019] Effects of the Invention

[0020] According to the driver state estimating device of the present invention, the driver's state can be accurately estimated regardless of the driving environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is an explanatory diagram of a vehicle equipped with a driver state estimation device according to an embodiment of the present invention.

[0022] Figure 2 This is a block diagram of a driver state estimation device according to an embodiment of the present invention.

[0023] Figure 3 This is a diagram illustrating the distribution of the driver's gaze points when visually checking the vehicle's traveling direction.

[0024] Figure 4 It is a graph showing the relationship between the size of the central range and the central confirmation ratio p.

[0025] Figure 5 is the central confirmation ratio p of the subjects with brain diseases u The central confirmation ratio p of the subjects without disease n Graph of the difference Δp.

[0026] Figure 6 This is a flowchart of the driver state estimation process according to the embodiment of the present invention.

[0027] Explanation of symbols

[0028] 1 vehicle

[0029] 10 controllers

[0030] 100 Driver status estimation device

[0031] 21Exterior camera device

[0032] 22 radar

[0033] 23 Navigation System

[0034] 24 positioning system

[0035] 25 vehicle speed sensor

[0036] 26 accelerometers

[0037] 27 yaw rate sensor

[0038] 28 steering angle sensor

[0039] 29 Steering torque sensor

[0040] 30 accelerometer sensors

[0041] 31 brake sensor

[0042] 32In-car camera

[0043] 36 displays

[0044] 37 speakers. DETAILED DESCRIPTION

[0045] Hereinafter, a driver state estimating device according to an embodiment of the present invention will be described with reference to the drawings.

[0046] [System Structure]

[0047] First, refer to Figure 1 and Figure 2 , the structure of the driver state estimation device of this embodiment is described. Figure 1 is an explanatory diagram of a vehicle equipped with a driver state estimation device. Figure 2 This is a block diagram of a driver state estimation device.

[0048] The vehicle 1 of this embodiment includes: a driving force source 2 such as an engine or an electric motor that outputs driving force; a transmission 3 that transmits the driving force output from the driving force source 2 to the drive wheels; a brake 4 that applies braking force to the vehicle 1; and a steering device 5 for steering the vehicle 1.

[0049] The driver state estimation device 100 is configured to estimate the state of the driver of the vehicle 1 and perform control of the vehicle 1 and driving support control as needed. Figure 2 As shown, the driver state estimation device 100 includes a controller 10, a plurality of sensor devices, a plurality of control systems, and a plurality of information output devices.

[0050] Specifically, the multiple sensor devices include an exterior camera 21 and a radar 22 for acquiring information about the driving environment of vehicle 1; a navigation system 23 and a positioning system 24 for detecting the position of vehicle 1. Furthermore, the multiple sensor devices include a vehicle speed sensor 25, an acceleration sensor 26, a yaw rate sensor 27, a steering angle sensor 28, a steering torque sensor 29, an accelerator sensor 30, and a brake sensor 31 for detecting the movement of vehicle 1 or the driver's driving operations. Furthermore, the multiple sensor devices include an interior camera 32 for detecting the driver's line of sight. The multiple control systems include a powertrain control module (PCM) 33 for controlling drive source 2 and transmission 3; a dynamic stability control system (DSC) 34 for controlling drive source 2 and brakes 4; and an electric power steering system (EPS) 35 for controlling steering system 5. The multiple information output devices include a display 36 for outputting image information and a speaker 37 for outputting audio information.

[0051] In addition, other sensor equipment may also include peripheral sonar for measuring the distance and position of surrounding structures relative to the vehicle 1, corner radar for measuring the approach of surrounding structures at the corners of the four parts of the vehicle 1, and various sensors for detecting the driver's status (such as heart rate sensors, electrocardiogram sensors, steering wheel grip force sensors, etc.).

[0052] The controller 10 performs various calculations based on signals received from a plurality of sensor devices, sends control signals to the PCM 33, DSC 34, and EPS 35 to properly operate the drive source 2, transmission 3, brakes 4, and steering system 5, and sends control signals to the display 36 and speaker 37 to output desired information. The controller 10 is configured as a computer having one or more processors 10a (typically CPUs), memory 10b (ROM, RAM, etc.) that stores various programs and data, and input / output devices.

[0053] The exterior camera 21 captures images of the surroundings of the vehicle 1 and outputs image data. The controller 10 identifies objects (e.g., preceding vehicles, parked vehicles, pedestrians, the road, lane markings (lane boundaries, white lines, yellow lines), traffic signals, traffic signs, stop signs, intersections, obstacles, etc.) based on the image data received from the exterior camera 21. Furthermore, the exterior camera 21 serves as an example of the "driving environment information acquisition device" in the present invention.

[0054] The radar 22 measures the position and speed of an object (especially a preceding vehicle, a parked vehicle, a pedestrian, a fallen object on the road, etc.). As the radar 22, for example, a millimeter wave radar can be used. The radar 22 transmits radio waves in the direction of travel of the vehicle 1, and receives reflected waves generated when the transmitted waves are reflected by the object. Then, the radar 22 measures the distance between the vehicle 1 and the object (for example, the distance between the vehicles), and the relative speed of the object relative to the vehicle 1 based on the transmitted waves and the received waves. In addition, in this embodiment, a laser radar, an ultrasonic sensor, etc. can be used instead of the radar 22 to measure the distance and relative speed to the object. In addition, a plurality of sensor devices can also be used to form a position and speed measuring device. In addition, the radar 22 is equivalent to an example of a "driving environment information acquisition device" in the present invention.

[0055] The navigation system 23 internally stores map information and can provide the map information to the controller 10. Based on the map information and the current vehicle position information, the controller 10 identifies roads, intersections, traffic signals, buildings, and the like surrounding the vehicle 1 (particularly in the direction of travel). The map information may also be stored within the controller 10. The positioning system 24 is a GPS system and / or a gyroscope system that detects the position of the vehicle 1 (current vehicle position information). Furthermore, the navigation system 23 and the positioning system 24 also constitute an example of the "driving environment information acquisition device" in the present invention.

[0056] The vehicle speed sensor 25 detects the speed of the vehicle 1 based on, for example, the rotational speed of the wheels or drive shaft. The acceleration sensor 26 detects the acceleration of the vehicle 1. This acceleration includes acceleration in the front-to-rear direction of the vehicle 1 and acceleration in the lateral direction (i.e., lateral acceleration). In this specification, acceleration includes not only the rate of change of speed in the direction of increasing speed but also the rate of change of speed in the direction of decreasing speed (i.e., deceleration).

[0057] The yaw rate sensor 27 detects the yaw rate of the vehicle 1. The steering angle sensor 28 detects the rotation angle (steering angle) of the steering wheel of the steering system 5. The steering torque sensor 29 detects the torque (steering torque) applied to the steering shaft via the steering wheel. The accelerator sensor 30 detects the amount of depression of the accelerator pedal. The brake sensor 31 detects the amount of depression of the brake pedal.

[0058] The in-vehicle camera 32 captures the driver's image and outputs image data. The controller 10 detects the driver's line of sight based on the image data received from the in-vehicle camera 32. The in-vehicle camera 32 is an example of a "line of sight detection device" in the present invention.

[0059] The PCM 33 controls the driving force source 2 of the vehicle 1 to adjust the driving force of the vehicle 1. For example, the PCM 33 controls the engine's spark plugs, fuel injection valves, throttle valve, variable valve mechanism, transmission 3, and the inverter that supplies power to the electric motor. When the vehicle 1 needs to be accelerated or decelerated, the controller 10 sends a control signal to the PCM 33 to adjust the driving force.

[0060] The DSC 34 controls the driving force source 2 and brakes 4 of the vehicle 1, performing deceleration control and posture control of the vehicle 1. For example, the DSC 34 controls the hydraulic pump and valve unit of the brakes 4, controlling the driving force source 2 via the PCM 33. When deceleration control or posture control of the vehicle 1 is required, the controller 10 sends a control signal to the DSC 34 to adjust the driving force or generate braking force.

[0061] The EPS 35 controls the steering system 5 of the vehicle 1. For example, the EPS 35 controls a motor that applies torque to the steering shaft of the steering system 5. When the traveling direction of the vehicle 1 needs to be changed, the controller 10 sends a control signal to the EPS 35 to change the steering direction.

[0062] The display 36 is provided in front of the driver in the vehicle cabin and displays image information to the driver. For example, a liquid crystal display or a head-up display is used as the display 36. The speaker 37 is provided in the vehicle cabin and outputs various audio information.

[0063] [Overview of Driver State Estimation]

[0064] Next, refer to Figures 3 to 5 , an overview of driver state estimation by the driver state estimation device 100 according to this embodiment will be described. Figure 3 This is a diagram illustrating the distribution of the driver's gaze points when visually checking the vehicle's traveling direction. Figure 4 Graph 1 is a graph showing the relationship between the size of the central range and the central confirmation ratio p, where the central confirmation ratio p represents the ratio of the gaze points included in the central range among all the gaze points. Figure 5 is the central confirmation ratio p when the anomaly occurs u Compared with the normal central confirmation ratio p n Graph of the difference Δp.

[0065] To investigate how a driver's visual activity (hereinafter referred to as "exploratory activity") changes between normal and abnormal driver states, the inventors conducted driving experiments using a driving simulator with multiple subjects with brain diseases and healthy subjects without diseases. Specifically, the subjects were instructed to drive in various driving environments (such as standard roads without intersections, standard roads with intersections, and highways) with varying numbers of objects to which the driver should pay attention (attention objects). The subjects' gaze movements were then measured while driving.

[0066] As a result, it can be seen that healthy test subjects without any disease (equivalent to normal drivers) basically direct their gaze toward the vicinity of the vehicle's direction of travel, and confirm the surroundings of the vehicle by repeatedly performing exploratory actions of temporarily moving their gaze toward objects of attention (such as other vehicles, interior rearview mirrors, side rearview mirrors, etc.) away from the direction of travel and then returning their gaze to the vicinity of the direction of travel.

[0067] On the other hand, among the subjects with brain diseases (equivalent to drivers in abnormal conditions), the following results were obtained: a higher proportion of them directed their gaze toward the direction of travel of the vehicle, and a lower proportion of them moved their gaze away from the direction of travel compared to the subjects without diseases.

[0068] Therefore, in order to quantitatively evaluate the proportion of people whose gazes are directed toward the direction of travel of the vehicle, the inventors extracted the gaze points where the gazes were fixed for a predetermined time (e.g., 0.3 seconds) for subjects with brain diseases and subjects without diseases, and obtained the distribution of the gaze points. Figure 3 As shown in the example, a predetermined visual range (hereinafter referred to as a "center range") including the direction of sight when the driver directs his sight toward the direction of travel of the vehicle is determined. Figure 3 The range of the circle A represented by the imaginary line in the image) contains the fixation point (in Figure 3 The number of fixations outside the central range (indicated by black circles in Figure 3 The ratio of the fixation points included in the central range among all the fixation points (hereinafter referred to as the “central confirmation ratio”) is calculated.

[0069] exist Figure 4 The figure shows the relationship between the size of the center range and the center confirmation ratio p when a driving experiment on a general road without intersections was conducted using a driving simulator. Figure 4 In the graph, the horizontal axis represents the size of the central area (the value of the radius of the central area at the perspective based on the driver's head position), and the vertical axis represents the central confirmation ratio p. Figure 4The dotted line in the middle represents the central confirmation ratio p of the subjects with brain diseases. u , the solid line represents the central confirmed proportion p of test subjects without disease n .

[0070] like Figure 4 As shown, regardless of the size of the central range, the central confirmation ratio p of the subjects with brain diseases u The central confirmation rate p of the subjects without disease n This indicates that the proportion of subjects with brain disease who look toward the direction of the vehicle's travel is higher than that of subjects without disease. Furthermore, in the range of 2 degrees to 15 degrees from the direction of the vehicle's travel, the central confirmation ratio p of subjects with brain disease is u The central confirmation ratio p of the subjects without disease n The difference is particularly large.

[0071] Here, the central confirmation ratio p of the subjects with brain disease is u The central confirmation ratio p of the subjects without disease n The difference Δp in Figure 5 In Figure 5 In the figure, the horizontal axis represents the size of the central range, and the vertical axis represents Δp=p u -p n .in addition, Figure 5 The solid line in the figure represents Δp when the driving experiment is conducted on a general road without intersections (i.e., a driving environment with an average number of attention objects), the single-dash line represents Δp when the driving experiment is conducted on a general road with intersections (i.e., a driving environment with a relatively large number of attention objects), and the dotted line represents Δp when the driving experiment is conducted on a highway (i.e., a driving environment with a relatively small number of attention objects).

[0072] like Figure 5 As shown, regardless of the driving environment, Δp has a peak in the central range of 2 degrees to 15 degrees. That is, the central confirmation ratio p of the subjects with brain disease is u The central confirmation ratio p of the subjects without disease n Moreover, the size of the central range of the peak value Δp is larger in a driving environment with a relatively large number of objects to be noticed ( Figure 5 The maximum value is 6 degrees in the case of the single-dot chain line, and the maximum value is 6 degrees in the case of the driving environment with a relatively small number of objects to pay attention to ( Figure 5 The dashed line) is the smallest (3 degrees), and in a driving environment with an average number of objects to pay attention to ( Figure 5The solid line shows the middle value (4 degrees) in the case of the attention object. This is because, the smaller the number of attention objects, the more likely the test subject with brain disease is to focus their sight on the direction of travel of the vehicle compared to the test subject without disease. This means that reducing the central range is more likely to result in a difference in the central confirmation ratio p, that is, it is easier to show a difference in the distribution of the gaze point. Therefore, by calculating the central confirmation ratio p from the distribution of the driver's gaze point, it is possible to correctly infer whether the driver's state is abnormal regardless of the driving environment. By setting the central range of an appropriate size according to the number of attention objects, it is possible to more accurately infer whether the driver's state is abnormal according to the driving environment.

[0073] [Driver status estimation process]

[0074] Next, refer to Figure 6 , the flow of the driver state estimation process using the driver state estimation device 100 of this embodiment will be described. Figure 6 This is a flowchart of a driver state estimation process for estimating the driver's state.

[0075] Figure 6 The driver state estimation process is started when the power of the vehicle 1 is turned on, and is repeatedly executed by the controller 10 at a predetermined cycle (for example, every 0.05 to 0.2 seconds).

[0076] When the driver state estimation process starts, the controller 10 obtains driving environment information based on the signals received from the sensor equipment including the external vehicle camera 21, radar 22, navigation system 23, positioning system 24, vehicle speed sensor 25, acceleration sensor 26, yaw angular velocity sensor 27, steering angle sensor 28, steering torque sensor 29, accelerator sensor 30 and brake sensor 31 (step S1).

[0077] Next, the controller 10 detects the driver's line of sight based on the signal received from the in-vehicle camera 32 (step S2 ).

[0078] Next, the controller 10 obtains objects (attention objects) that the driver should pay attention to in the direction of travel of the vehicle 1 based on the driving environment information obtained in step S1 (step S3). Examples of attention objects include other vehicles, obstacles, pedestrians, traffic lights, road signs, etc.

[0079] Next, the controller 10 obtains the distribution of the driver's gaze points in the most recent prescribed time (e.g., 30 seconds) based on the driver's line of sight detected in step S2 (step S4). For example, based on the driver's line of sight detected in step S2, when it is detected that the driver's line of sight has stagnated for a prescribed time (e.g., 0.3 seconds), the controller 10 uses a combination of an azimuth angle and an elevation angle based on the direction of travel of the vehicle to represent the direction of the line of sight, that is, the direction from the driver's head position toward the gaze point, and determines the position of the gaze point. The positions of each determined gaze point are then accumulated in the memory 10b. The accumulation of the positions of the gaze points is repeated during the execution of the driver state estimation process. Then, in step S4, the controller 10 reads out the gaze point positions of the most recent prescribed time accumulated in the memory 10b, and obtains the distribution of the gaze points.

[0080] Next, the controller 10 determines whether the number of cautionary objects obtained in step S3 is greater than a predetermined threshold value N1 (step S5). N1 is preset and stored in the memory 10b. A driving environment where the number of cautionary objects is less than N1 corresponds to a driving environment with relatively few cautionary objects, such as a highway.

[0081] As a result, if the number of attention objects is not greater than N1 (i.e., less than N1) (step S5: No), the controller 10 sets a central area A1 of a size corresponding to a driving environment with a relatively small number of attention objects and calculates the proportion of gaze points included in central area A1 (central confirmation ratio p) (step S6). Central area A1 is set to a circular area centered on the average direction of the distribution of gaze directions over a recent specified period of time (e.g., 30 seconds). Furthermore, the size of central area A1 (the value representing the radius of the central area based on the driver's head position) is set to, for example, 3 degrees based on the results of the aforementioned driving experiment.

[0082] On the other hand, if the number of caution objects is greater than N1 (step S5: Yes), the controller 10 determines whether the number of caution objects acquired in step S3 is greater than a predetermined threshold value N2 (step S7). N2 is a value greater than N1 and is pre-set and stored in the memory 10b. A driving environment where the number of caution objects is greater than N1 and less than N2 corresponds to a driving environment where the number of caution objects is average, such as a typical road without intersections. Furthermore, a driving environment where the number of caution objects is greater than N2 corresponds to a driving environment where the number of caution objects is relatively high, such as a typical road with intersections.

[0083] If the number of attention objects is not greater than the predetermined threshold value N2 (i.e., greater than N1 and less than N2) (step S7: No), the controller 10 sets a central area A2 of a size corresponding to the driving environment with an average number of attention objects and calculates the proportion of gaze points included in central area A2 (central confirmation ratio p) (step S8). Central area A2 is set to a circular area centered on the average direction of the distribution of gaze directions over a recent predetermined period of time (e.g., 30 seconds). The size of central area A2 is set to 4 degrees, for example, based on the results of the aforementioned driving experiment.

[0084] If the number of attention objects is greater than N2 (step S7: Yes), the controller 10 sets a central area A3 of a size appropriate for a driving environment with a relatively large number of attention objects and calculates the proportion of gaze points included in central area A3 (central confirmation ratio p) (step S9). Central area A3 is set to a circular area centered on the average direction of the distribution of gaze directions over a recent predetermined period of time (e.g., 30 seconds). The size of central area A3 is set to 6 degrees, for example, based on the results of the aforementioned driving experiment.

[0085] After the processing of step S6, S8 or S9, the controller 10 determines whether the calculated center confirmation ratio p is a threshold value p. th Above (step S10). Threshold value p th is preset and stored in the memory 10b. th For example, it is set to 0.5 based on the results of the above-mentioned driving experiment.

[0086] As a result, the central confirmation ratio p is the threshold p th In the above case (step S10: YES), it is considered that the driver's line of sight is focused on the central area and rarely moves outside the central area. Therefore, the controller 10 estimates that the driver is in an abnormal state (step S11).

[0087] Next, the controller 10 sends a control signal to the display 36 and the speaker 37, and an alarm is outputted from the display 36 and the speaker 37 to inform the driver of the abnormal state (step S12). At this time, the display 36 and the speaker 37 may output image information and sound information (sight guidance information) to guide the driver's sight to the attention object that the driver has not visually recognized.

[0088] In addition, the central confirmation ratio p is not the threshold p th In the above case (step S10: YES), it is considered that the driver frequently moves his line of sight not only within the central range but also outside the central range. Therefore, the controller 10 estimates that the driver's state is normal (step S13).

[0089] After step S12 or S13 , the controller 10 ends the driver state estimation process.

[0090] [Modification]

[0091] In addition, in the above-mentioned embodiment, the central range is described as being set as a circular range centered on the average direction of the distribution of the line of sight direction in the most recent specified time (for example, 30 seconds), but the central range can also be a range centered on the vehicle's direction of travel, or a shape other than a circle.

[0092] [Function, effect]

[0093] Next, the effects of the driver state estimation device 100 according to the above-described embodiment will be described.

[0094] The ratio of all the gaze points included in the distribution of the driver's gaze points within the predetermined time period that is included in the central range of the direction of sight when the driver's gaze is directed in the direction of travel of the vehicle 1 (central confirmation ratio p) is a predetermined threshold value p. th In the above case, the controller 10 infers that the driver is in an abnormal state. Therefore, based on the central confirmation ratio p, it can determine that the driver's line of sight has a stronger tendency to focus near the direction of travel due to a certain disease, and can correctly infer that the driver is in an abnormal state regardless of the driving environment.

[0095] Furthermore, the controller 10 sets the size of the central range based on the driving environment information. Therefore, by setting an appropriate size of the central range according to the driving environment information, it is possible to more accurately estimate whether the driver's condition is abnormal based on the driving environment.

[0096] In addition, when the number of attention objects is greater than a specified threshold, the controller 10 sets the central range to be larger than when the number of attention objects is less than the specified threshold. Therefore, based on the characteristic that the smaller the number of attention objects, the stronger the tendency of the driver in the abnormal state to concentrate his or her line of sight near the direction of travel of the vehicle 1, the size of the central range in which the difference from the driver in the normal state is likely to occur can be set, and whether the driver's state is abnormal can be more accurately inferred according to the driving environment.

[0097] In addition, the controller 10 sets a circular range centered on the average direction of the distribution of line of sight directions within a specified time as a central range. Therefore, the central range can be set as a basis for estimating the driver's state based on the actual line of sight direction of the driver, and whether the driver's state is abnormal can be more accurately estimated.

Claims

1. A driver state estimation device for estimating the state of a driver driving a vehicle, characterized in that: have: a sight line detection device, the sight line detection device detecting the sight line of the driver; as well as a controller configured to estimate the driver's state based on the driver's line of sight, The controller is configured as follows: setting a predetermined visual range including the visual direction of the driver when the driver directs his / her visual line of sight toward the traveling direction of the vehicle; Based on the driver's sight line, the distribution of the driver's gaze points within a specified time is obtained, When the ratio of the gaze points included in the predetermined visual range among all the gaze points included in the acquired distribution of gaze points is equal to or greater than a predetermined ratio, it is estimated that the driver is in an abnormal state.

2. The driver state estimation device according to claim 1, characterized in that: It also includes a driving environment information acquisition device, which acquires the driving environment information of the vehicle. The controller is configured to set a size of the predetermined visual range based on the driving environment information.

3. The driver state estimation device according to claim 2, characterized in that: The controller is configured as follows: Based on the driving environment information, the number of attention objects around the vehicle is obtained. When the number of the attention objects is equal to or greater than a predetermined threshold, the predetermined visual range is set larger than when the number of the attention objects is smaller than the predetermined threshold.

4. The driver state estimation device according to claim 1 or 2, characterized in that: The controller is configured as follows: Based on the driver's line of sight, a circular range centered on an average direction of distribution of line of sight directions within a predetermined time is set as the predetermined visual range.

5. The driver state estimation device according to claim 1 or 2, characterized in that: The predetermined visual range is a range of 2 degrees to 15 degrees centered on the traveling direction of the vehicle.

6. The driver state estimation device according to claim 5, characterized in that: The predetermined visual range is a range of 3 to 6 degrees centered on the traveling direction of the vehicle.

Images