Information presenting method and information presenting device

Abstract

In this information presenting method, a controller executes: processing (S1) for measuring an amount of brain activity of a driver in response to visual information relating to the surroundings of a vehicle presented by means of a visual information presenting device provided in the vehicle; and processing (S4, S5) for controlling a spatial range that is visible to the driver from the visual information presented by the visual information presenting device, on the basis of the results of the measurement of the amount of brain activity.

Description

Information presentation method and information presentation device

[0001] The present invention relates to an information presentation method and an information presentation device.

[0002] The following Patent Document 1 describes a driving assistance device that displays images captured by an external camera capable of capturing a specified area outside the vehicle on a monitor visible to the driver, in which only a set area of ​​the image captured by the external camera, which is set as an area narrower than the specified area, is displayed on the monitor.

[0003] JP 2018-018760 A

[0004] By presenting visual information about the vehicle's surroundings to the driver using a visual information presentation device such as a display device or a rearview mirror, the driver can understand the situation around the vehicle. However, since perception of visual information varies from person to person, if the spatial range visible from the visual information presented by the visual information presentation device is not appropriate for each driver, it may be difficult for the driver to understand the situation around the vehicle. The present invention aims to make it easier for the driver to perceive the visual information about the vehicle's surroundings presented by the visual information presentation device.

[0005] In one aspect of the information presentation method of the present invention, a controller performs the following processes: measuring the driver's brain activity in response to visual information about the area around the vehicle that is presented by a visual information presentation device installed in the vehicle; and controlling the spatial range that the driver can see from the visual information presented by the visual information presentation device based on the results of the brain activity measurement.

[0006] According to the present invention, it is possible to make it easier for a driver to recognize visual information about the surroundings of a vehicle, which is presented by a visual information presentation device. The objects and advantages of the present invention are realized and attained by using the elements and combinations set forth in the claims. It should be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not intended to limit the invention as defined by the claims.

[0007] FIG. 1 is a schematic diagram of a vehicle equipped with an information presentation device according to an embodiment. FIGS. 1A and 1B are diagrams showing time changes in total hemoglobin concentration (total - Hb) in the dorsolateral prefrontal cortex when an image including multiple objects is presented to drivers of different genders. FIG. 1 is a block diagram of an example of the functional configuration of a controller. FIGS. 1A to 1D are schematic diagrams for explaining a method of reducing the visible range. FIG. 1 is a flowchart of an example of an information presentation method according to a first embodiment. FIG. 1 is a flowchart of an example of an information presentation method according to a second embodiment. FIG. 1 is a flowchart of an example of an information presentation method according to a third embodiment.

[0008] 1 is a schematic diagram of a vehicle equipped with an information presentation device according to an embodiment. The vehicle 1 includes a surrounding environment sensor 11, a visual information presentation device 12, a brain activity sensor 13, a visual target sensor 14, a threshold database (threshold DB) 15, and a controller 16.

[0009] The surrounding environment sensor 11 is a sensor that detects the surrounding environment of the vehicle 1 (e.g., objects around the vehicle 1). The surrounding environment sensor 11 detects the surrounding environment of the vehicle 1, such as the relative position of the vehicle 1 and objects present around the vehicle 1, the distance between the vehicle 1 and the objects, and the direction in which the objects are present. The surrounding environment sensor 11 may include, for example, a camera that captures the surrounding environment of the vehicle 1. Furthermore, for example, the vehicle 1 may include a distance measuring device such as a laser range finder (LRF), radar, or LiDAR (Light Detection and Ranging) laser radar, or a sonar sensor that detects obstacles around the vehicle 1. The surrounding environment sensor 11 outputs surrounding environment information, which is information on the detected surrounding environment of the vehicle 1, to the controller 16.

[0010] The visual information presentation device 12 presents visual information representing the surroundings of the vehicle 1 to the driver of the vehicle 1. For example, the visual information presentation device 12 may be a display device (e.g., a back view monitor, a rear view monitor, a side view monitor, an around view monitor, a see-through A-pillar, a see-through hood, etc.) that displays, as visual information, an image of the surroundings of the vehicle 1 (e.g., an image behind the vehicle 1) captured by the camera of the surrounding environment sensor 11. Furthermore, for example, the visual information presentation device 12 may display, as visual information, a CG image representing the location of other vehicles and obstacles around the vehicle 1 based on the detection results of other vehicles and obstacles around the vehicle 1 by the surrounding environment sensor 11. Furthermore, for example, the visual information presentation device 12 may be a mirror (e.g., an interior rearview mirror or an exterior rearview mirror) that reflects the scenery around the vehicle 1 (e.g., behind or to the rear side of the vehicle 1) to present visual information about the surroundings of the vehicle 1 to the driver.

[0011] Brain activity sensor 13 is a sensor that detects the brain activity of the driver. For example, brain activity sensor 13 may be an electroencephalogram (EEG) sensor that detects the brain waves of the driver, a magnetoencephalogram (MEG) that detects brain magnetic fields, or an electroencephalogram (EEG) that detects brain potentials. It may also be a brain function imaging device that measures the activity state of the driver's brain surface using functional near-infrared spectroscopy (fNIRS). In the case of a brain function imaging device, brain activity sensor 13 may include a near-infrared light transmitter and receiver. Brain activity sensor 13 inputs detected brain activity data related to the driver's brain activity to controller 16.

[0012] The visual target sensor 14 is a sensor used to detect a visual target that is an object being viewed by the driver. For example, the visual target sensor 14 may be a gaze measuring device that measures the three-dimensional position of the driver's viewpoint and the direction of his / her line of sight. The visual target sensor 14 inputs gaze data indicating the three-dimensional position of the driver's viewpoint and the direction of his / her line of sight to the controller 16.

[0013] The controller 16 is an electronic control unit (ECU) that controls the visual information presented by the visual information presentation device 12 in accordance with the driver's brain activity in response to the visual information about the vehicle surroundings presented by the visual information presentation device 12. The controller 16 includes a processor 16a and peripheral components such as a storage device 16b. The processor 16a may be, for example, a central processing unit (CPU) or a micro-processing unit (MPU). The storage device 16b may include a semiconductor storage device, a magnetic storage device, an optical storage device, or the like. The storage device 16b may include memories such as a read-only memory (ROM) and a random access memory (RAM) used as main storage devices, as well as registers and cache memories.

[0014] The functions of the controller 16 described below are realized, for example, by the processor 16a executing a computer program stored in the storage device 16b. The controller 16 may also be formed of dedicated hardware for executing the information processing described below. For example, the controller 16 may include a functional logic circuit configured in a general-purpose semiconductor integrated circuit. The controller 16 may also include a programmable logic device (PLD) such as a field-programmable gate array (FPGA).

[0015] The controller 16 controls the spatial range that the driver can see from the visual information presented by the visual information presentation device 12 (hereinafter, this may be referred to as the "visible range"), depending on the amount of brain activity of the driver in response to the visual information around the vehicle presented by the visual information presentation device 12. The reason for this is explained below. In driving situations such as parking and changing lanes, the driver grasps the positional relationship of obstacles around the vehicle 1 based on the visual information around the vehicle presented by the visual information presentation device 12 (for example, the camera image of the surrounding environment sensor 11 and the mirror image from the rearview mirror).

[0016] Generally, it is considered preferable for the driver to have a wide visible range from the visual information provided by the visual information presentation device 12; however, depending on the individual's characteristics, a wide visible range may make it difficult to understand the forward and backward positions of obstacles. The reason why it is difficult to understand the relative positions of surrounding objects when the visible spatial range is wide is that object vision and space vision are involved in the recognition and judgment of visual information. Object vision is information processing for recognizing "what the object being viewed is," while space vision is information processing for recognizing "the position and spatial relationship of the object being viewed."

[0017] When visual information including multiple obstacles is presented, people who understand the positional relationships based on object vision rather than spatial vision may be able to easily grasp the positional relationships of the multiple obstacles, while people who understand the positional relationships based on spatial vision rather than object vision may have difficulty understanding the positional relationships of the multiple obstacles. For example, in a 3D virtual reality space, it is known that women tend to perceive a sense of presence through object vision, while men tend to perceive a sense of presence through spatial vision (So-Yeon Yoon et al.: User attributes in processing 3D VR-enabled showroom: Gender, visual cognitive styles, and the sense of presence, Cornell University, International Journal of Human-Computer Studies, Volume 82, Pages 1-10 (2015)).

[0018] Here, because the visual information presented by the visual information presentation device 12 is not an actual image, it is believed to have a tendency similar to the above-mentioned research results in a three-dimensional virtual reality space. Figures 2(a) and 2(b) show the time change in total hemoglobin concentration (total - Hb) in the dorsolateral prefrontal cortex when drivers of different genders were presented with an image containing multiple objects and asked to judge the longitudinal positional relationship of the objects. Figures 2(a) and 2(b) show the experimental results for men and women, respectively.

[0019] Because the working memory of the dorsolateral prefrontal cortex is used to recognize and judge visual information, detecting brain activity in the dorsolateral prefrontal cortex can measure the driver's cognitive load in relation to visual information. The more difficult it is for the subject to recognize and judge visual information, the higher the cognitive load is thought to be. In this experiment, functional near-infrared spectroscopy (fNIRS) was used to measure total hemoglobin concentration (total - Hb) in the dorsolateral prefrontal cortex, which was then used to calculate cerebral blood flow and detect brain activity.

[0020] In the period immediately after the image was presented, the cerebral blood flow of male drivers increased, as shown by the dashed-dotted line 20 in Figure 2(a). In contrast, the cerebral blood flow of female drivers decreased, as shown by the dashed-dotted line 21 in Figure 2(b). This tendency was the same when a two-dimensional image was presented (dashed line) and when a three-dimensional image was presented (solid line). This indicates that male drivers, who understand positional relationships based on spatial vision, tend to have difficulty understanding the longitudinal positional relationships of multiple objects in an image that includes these objects.

[0021] When the visible range is wide, depending on the individual's characteristics, it may be difficult for the driver to understand the forward / backward positions of surrounding obstacles. Therefore, it is necessary to reduce the visible range depending on the individual's characteristics to make it easier for the driver to understand the forward / backward positions of obstacles. Therefore, the controller 16 determines whether the driver understands the positional relationship of objects based on spatial vision rather than object vision, based on the driver's brain activity in response to the visual information presented by the visual information presentation device 12.

[0022] When it is determined that the driver understands the positional relationship based on spatial vision rather than object vision, the controller 16 controls the visual information presentation device 12 to reduce the visible range. As a result, for a driver who has difficulty understanding the forward and backward positions of surrounding obstacles when the visible range is wide, the visible range can be reduced to reduce the number of obstacles included in the visual information, making it easier for the driver to understand the positional relationship of obstacles from the visual information.

[0023] FIG. 3 is a block diagram of an example of the functional configuration of the controller 16. The controller 16 includes a brain activity analysis unit 30, a cognitive load calculation unit 31, a visual target determination unit 32, and a visible range control unit 33. The brain activity analysis unit 30 analyzes the detection signal output from the brain activity sensor 13 to detect brain activity signals (e.g., EEG (Electroencephalography) data, MEG (Magnetoencephalography) data, fNIRS data, etc.) from the dorsolateral prefrontal cortex of the driver's brain. The brain activity analysis unit 30 determines the amount of brain activity in the dorsolateral prefrontal cortex of the driver's brain based on the intensity of the detected brain activity signals. For example, it may be determined based on fNIRS data that the greater the cerebral blood flow in the dorsolateral prefrontal cortex, the greater the amount of brain activity.

[0024] The cognitive load calculation unit 31 determines the level of the driver's cognitive load based on the amount of brain activity in the dorsolateral prefrontal cortex determined by the brain activity analysis unit 30. Specifically, the cognitive load calculation unit 31 determines that the greater the amount of brain activity in the dorsolateral prefrontal cortex, the higher the driver's cognitive load. In the following description, the amount of brain activity in the driver's dorsolateral prefrontal cortex may be simply referred to as "amount of brain activity." The visual target determination unit 32 determines whether the driver's visual target is the visual information presentation device 12 (i.e., whether the visual information output by the visual information presentation device 12 is the visual target) based on the gaze data (the three-dimensional position of the driver's viewpoint and the direction of the gaze) output by the visual target sensor 14.

[0025] The visual target determination unit 32 may determine whether the driver's line of sight is directed toward the visual information presentation device 12, based on the known three-dimensional position information of the visual information presentation device 12, the three-dimensional position of the driver's viewpoint, and the direction of the driver's line of sight. If the driver's line of sight is directed toward the visual information presentation device 12, it may determine that the visual target of the driver is the visual information presentation device 12.

[0026] Furthermore, the visual target determination unit 32 may determine the driver's attention state in addition to determining whether the driver's line of sight is directed toward the visual information presentation device 12. For example, the visual target determination unit 32 may measure the driver's eye movement to detect the eye fixation start time, which is the end time of saccade movement. The driver's eye movement may be measured based on gaze data output by the visual target sensor 14, for example, or may be detected based on an electro-oculography (EOG) method. The visual target determination unit 32 then extracts an eye fixation related potential (EFRP) waveform by extracting the driver's electroencephalogram starting from the eye fixation start time, and analyzes the extracted EFRP waveform.

[0027] The analysis interval, which is a time interval for analyzing the EFRP waveform, is divided into multiple subintervals. The visual target determination unit 32 identifies which subinterval the extracted EFRP waveform belongs to. When multiple EFRPs are classified into a certain subinterval, the visual target determination unit 32 averages the EFRPs for each subinterval. The visual target determination unit 32 determines the driver's attention state for each subinterval based on the EFRP for each subinterval. For example, it may determine whether the driver is concentrating by comparing the amplitude value of the lambda response of the EFRP with a threshold value.

[0028] When the driver's line of sight is directed toward the visual information presentation device 12 and the driver is in a state of concentrated attention, the visual target determination unit 32 may determine that the visual target of the driver is the visual information presentation device 12. Note that when multiple visual information presentation devices 12 are provided in the vehicle, the visual target determination unit 32 may determine which of the multiple visual information presentation devices 12 is the visual target of the driver.

[0029] The visible range control unit 33 controls the visual information presentation device 12 to reduce the visible range that the driver can see from the visual information presented by the visual information presentation device 12, based on the amount of brain activity (e.g., the driver's cognitive load) determined by the cognitive load calculation unit 31. That is, the visible range is controlled based on the measurement results of the amount of brain activity determined by the brain activity analysis unit 30. Specifically, the visible range control unit 33 determines whether the driver understands the positional relationship of objects based on spatial vision rather than object vision, based on the amount of brain activity. If it is determined that the driver understands the positional relationship based on spatial vision rather than object vision, the visual information presentation device 12 is controlled to reduce the visible range.

[0030] For example, the visible range control unit 33 determines that the driver understands the positional relationship based on spatial vision rather than object vision when the amount of brain activity is greater than the discrimination threshold Th within a predetermined time after the visual target determination unit 32 determines that the driver's visual target is the visual information presentation device 12 (for example, immediately after determining that the driver's visual target is the visual information presentation device 12). For example, the visible range control unit 33 may determine that the driver understands the positional relationship based on spatial vision rather than object vision when multiple obstacles are visible from the visual information presented by the visual information presentation device 12 and the amount of brain activity is greater than the discrimination threshold Th within a predetermined time after determining that the driver's visual target is the visual information presentation device 12.

[0031] Furthermore, for example, the visible range control unit 33 may detect the distance between the vehicle 1 and an obstacle around the vehicle 1 based on an image captured by a camera of the surrounding environment sensor 11 or a detection signal from a laser range finder, radar, LiDAR, laser radar, or sonar sensor. If the distance between the vehicle 1 and the obstacle is less than a threshold value despite an increase in brain activity after it is determined that the driver's visual target is the visual information presentation device 12, the visible range control unit 33 may determine that the driver understands the positional relationship based on spatial vision rather than object vision.

[0032] For example, the visible range control unit 33 may determine that the amount of brain activity has increased after it has been determined that the driver's visual target is the visual information presentation device 12 if the amount of brain activity within a predetermined time after it has been determined that the driver's visual target is the visual information presentation device 12 (for example, immediately after it has been determined that the driver's visual target is the visual information presentation device 12) is greater than the discrimination threshold Th.

[0033] When it is determined that the driver understands positional relationships based on spatial vision rather than object vision, the visible range control unit 33 controls the visual information presentation device 12 to reduce the visible range. When the visual information presentation device 12 is a display device that displays images of the surroundings of the vehicle 1 captured by the camera of the surrounding environment sensor 11 and CG images showing the locations of other vehicles and obstacles, the visible range control unit 33 reduces the visible range that the driver can see from the image presented by the display device by reducing the area in which the image is displayed.

[0034] 4(a) and 4(b) are shown. Reference numeral 40 denotes a display screen of the visual information presentation device 12, which is a display device. Fig. 4(a) shows the display state of the visual information presentation device 12 in a normal state before the visible range is reduced, and Fig. 4(b) shows the display state of the visual information presentation device 12 after the visible range has been reduced. For example, as shown in Fig. 4(b), the visible range control unit 33 may reduce the visible range by reducing an area 41 of the display screen 40 on which an image captured by a camera is displayed.

[0035] See FIG. 4( c). For example, the visible range control unit 33 may reduce the visible range by blocking a portion of the image displayed on the display screen 40 with masks 42 to 45. For example, the masks 42 and 43 may be arranged at positions on the display screen 40 where a mirror image of a pillar inside the vehicle 1 would be visible to the driver if the display screen 40 of the visual information presentation device 12, which is a display device, were a mirror. Also, for example, the masks 44 and 44 may be arranged at positions on the display screen 40 where a mirror image of a headlight in the rear seat of the vehicle 1 would be visible to the driver if the display screen 40 of the visual information presentation device 12 were a mirror. These masks 42 to 45 may be superimposed with pseudo images that resemble pillars or headlights.

[0036] 4(d) . For example, the visible range control unit 33 may reduce the visible range by increasing the magnification at which the display device, which is the visual information presentation device 12, displays an image. For example, if obstacles 46 and 47 (e.g., obstacles behind the vehicle 1) are shown near the center of the display screen 40, the central portion of the image captured by the camera may be enlarged and displayed on the display screen.

[0037] If the visual information presentation device 12 is a mirror such as an interior rearview mirror or an exterior rearview mirror, the visible range control unit 33 may reduce the visible range by reducing the area on which the mirror reflects an image or by blocking part of the mirror. For example, the visible range control unit 33 may reduce the area on which the mirror reflects an image or by blocking part of the mirror by controlling the transparency of a light-transmitting member (e.g., glass) on the surface of the mirror of the visual information presentation device 12. For example, the visible range control unit 33 may reduce the area on which the mirror reflects an image or by blocking part of the mirror by controlling a liquid crystal device provided on the surface of the mirror of the visual information presentation device 12.

[0038] (Operation) Figure 5 is a flowchart of an example of the information presentation method of the first embodiment. In step S1, the brain activity sensor 13 measures the brain activity of the driver. In step S2, the visual target sensor 14 measures the three-dimensional position of the driver's viewpoint and the direction of his / her line of sight. In step S3, the visual target determination unit 32 of the controller 16 determines whether or not the driver is viewing the visual information presentation device 12. If the driver is not viewing the visual information presentation device 12 (step S3: N), the process returns to step S1. If the driver is viewing the visual information presentation device 12 (step S3: Y), the process proceeds to step S4.

[0039] In step S4, the visible range control unit 33 determines whether the driver understands the positional relationships of objects based on spatial vision rather than object vision. If the driver does not understand the positional relationships of objects based on spatial vision rather than object vision (step S4: N), for example, if the driver understands the positional relationships of objects based on object vision rather than spatial vision, the process proceeds to step S6. If the driver understands the positional relationships of objects based on spatial vision rather than object vision (step S4: Y), the process proceeds to step S5.

[0040] In step S5, the visible range control unit 33 controls the visual information presentation device 12 to reduce the visible range. The process then proceeds to step S6. In step S6, the controller 16 determines whether the ignition key of the vehicle 1 has been turned off. If the ignition key has not been turned off (step S6: N), the process returns to step S1. If the ignition key has been turned off (step S6: Y), the process ends.

[0041] Second Embodiment The visible range control unit 33 in the second embodiment reads out a discrimination threshold Th of brain activity used when determining whether the driver understands positional relationships based on spatial vision rather than object vision from the threshold database 15 shown in FIG. 1 . For example, the threshold database 15 may store a discrimination threshold Th corrected for each individual driver. The visible range control unit 33 may identify the driver currently driving the vehicle 1 (e.g., the person sitting in the driver's seat), read out the discrimination threshold Th stored in association with the identified driver from the threshold database 15, and use the discrimination threshold Th when determining whether the driver understands positional relationships based on spatial vision rather than object vision.

[0042] Furthermore, for example, the threshold database 15 may store a discrimination threshold Th adjusted to suit each of a plurality of visual information presentation devices 12 (e.g., a back view monitor, a rear view monitor, a side view monitor, an around view monitor, a see-through A-pillar, a see-through hood, and a rearview mirror). In other words, the threshold database 15 may store a discrimination threshold Th adjusted to suit the visual information presented by a plurality of visual information presentation devices 12.

[0043] The visible range control unit 33 may read from the threshold database 15 the discrimination threshold Th stored in association with the visual information presentation device 12 determined by the visual target determination unit 32 to be the visual target of the driver, and may use the discrimination threshold Th when determining whether the driver understands the positional relationship based on spatial vision rather than object vision. For example, the visible range control unit 33 may determine that the driver understands the positional relationship based on spatial vision rather than object vision when the amount of brain activity within a predetermined time after the visual target determination unit 32 determines that the visual target of the driver is the visual information presentation device 12 (e.g., immediately after determining that the visual target of the driver is the visual information presentation device 12) is greater than the discrimination threshold Th.

[0044] Furthermore, for example, if the amount of brain activity within a predetermined time after it is determined that the driver's visual target is the visual information presentation device 12 (for example, immediately after it is determined that the driver's visual target is the visual information presentation device 12) is greater than the discrimination threshold Th, the visible range control unit 33 may determine that the amount of brain activity of the driver has increased after it is determined that the driver's visual target is the visual information presentation device 12. If the distance between the vehicle 1 and an obstacle is less than a threshold even though the amount of brain activity has increased after it is determined that the driver's visual target is the visual information presentation device 12, it may be determined that the driver understands the positional relationship based on spatial vision rather than object vision.

[0045] 6 is a flowchart of an example of the information presentation method according to the second embodiment. The processes of steps S11 to S13 are the same as the processes of steps S1 to S3 in FIG. 5. If the driver is not visually recognizing the visual information presentation device 12 (step S13: N), the process returns to step S11. If the driver is visually recognizing the visual information presentation device 12 (step S13: Y), the process proceeds to step S14. In step S14, the visible range control unit 33 reads out the discrimination threshold value Th from the threshold value database 15.

[0046] In step S15, the visible range control unit 33 determines whether the amount of brain activity of the driver is higher than the discrimination threshold Th. If the amount of brain activity is not higher than the discrimination threshold Th (step S15: N), the process proceeds to step S16. If the amount of brain activity is higher than the discrimination threshold Th (step S16: Y), the process proceeds to step S16. In step S16, the visible range control unit 33 determines that the driver understands positional relationships based on spatial vision rather than object vision.

[0047] If it is not determined that the driver understands the positional relationship based on spatial vision rather than object vision (step S17: N), the process proceeds to step S20. If it is determined that the driver understands the positional relationship based on spatial vision rather than object vision (step S17: Y), the process proceeds to step S18. In step S18, the visual information presentation device 12 is controlled to reduce the visible range.

[0048] In step S19, the visible range control unit 33 corrects the value of the discrimination threshold Th read from the threshold database 15 in step S14 to a higher value. The visible range control unit 33 updates the value of the discrimination threshold Th stored in the threshold database 15 to the corrected value. Thereafter, the process proceeds to step S21.

[0049] In step S20, the value of the discrimination threshold Th read from the threshold database 15 in step S14 is corrected to a lower value. The visible range control unit 33 updates the value of the discrimination threshold Th stored in the threshold database 15 to the corrected value. Thereafter, the process proceeds to step S21. In step S21, the controller 16 determines whether the ignition key of the vehicle 1 has been turned off. If the ignition key has not been turned off (step S21: N), the process returns to step S11. If the ignition key has been turned off (step S21: Y), the process ends.

[0050] Third Embodiment In a third embodiment, the visible range control unit 33 recognizes obstacles visible to the driver from the visual information presented by the visual information presentation device 12. The visible range control unit 33 determines whether or not the driver will be unable to see obstacles necessary for driving among obstacles around the vehicle 1 when the visual information presentation device 12 is controlled to reduce the visible range.

[0051] For example, the visible range control unit 33 may detect the relative positional relationship and relative speed between the vehicle 1 and obstacles around the vehicle 1 based on images captured by the camera of the surrounding environment sensor 11 or detection signals from a laser range finder, radar, LiDAR, laser radar, or sonar sensor. For example, the visible range control unit 33 may determine for each obstacle whether the driver can see the obstacle using the visual information presented by the visual information presentation device 12, based on the relative positional relationship between the obstacle and the vehicle 1. Furthermore, the visible range control unit 33 may determine for each obstacle whether the driver will not be able to see the obstacle if the visible range is reduced.

[0052] For example, the visible range control unit 33 may determine, for each of these obstacles, whether or not the driver needs to be aware of the obstacle in order to drive the vehicle 1, based on the relative positional relationship between the obstacle and the vehicle 1. For example, the visible range control unit 33 may determine that the obstacle is an obstacle that the driver needs to be aware of when the obstacle is present within a predetermined distance range from the vehicle 1. Alternatively, for example, the visible range control unit 33 may determine that the obstacle is an obstacle that the driver needs to be aware of based on the relative positional relationship and relative speed between the obstacle and the vehicle 1. For example, the visible range control unit 33 may determine that the obstacle is an obstacle that the driver needs to be aware of when the vehicle 1 and the obstacle are approaching each other. Alternatively, for example, the visible range control unit 33 may determine that the obstacle is an obstacle that the driver needs to be aware of when it is predicted that the distance between the vehicle 1 and the obstacle will be less than a predetermined distance within a predetermined time.

[0053] If reducing the visible range would cause the driver to be unable to see an obstacle that the driver needs to see in order to drive the vehicle 1, the visible range control unit 33 prohibits controlling the visual information presentation device 12 to reduce the visible range. If reducing the visible range does not cause the driver to be unable to see an obstacle that the driver needs to see in order to drive the vehicle 1, the visible range control unit 33 permits controlling the visual information presentation device 12 to reduce the visible range.

[0054] 7 is a flowchart of an example of an information presentation method according to the third embodiment. The processes of steps S31 to S34 are the same as steps S1 to S4 in FIG. 5. If the driver does not understand the positional relationship based on spatial vision rather than object vision (step S34: N), the process proceeds to step S37. If the driver understands the positional relationship based on spatial vision rather than object vision (step S34: Y), the process proceeds to step S35. In step S35, the visible range control unit 33 determines whether reducing the visible range will cause the driver to become unable to see obstacles that the driver needs to see in order to drive the vehicle 1.

[0055] If the driver is not unable to see the obstacles necessary for driving the vehicle 1 (step S35: N), the process proceeds to step S36. If the driver is unable to see the obstacles necessary for driving the vehicle 1 (step S: Y), step S36 is skipped and the process proceeds to step S37. This prohibits the visual information presentation device 12 from being controlled to reduce the visible range. The processes of steps S36 and S37 are the same as steps S5 and S6 of FIG. 5.

[0056] (Effects of the embodiment) (1) The controller 16 executes a process of measuring the brain activity of the driver in response to the visual information around the vehicle that is presented to the driver by the visual information presentation device 12, and a process of controlling, based on the measurement result of the brain activity, the spatial range that the driver can see from the visual information presented by the visual information presentation device 12. This makes it possible to switch the visible range in accordance with the visual perception ability of the individual driver, thereby improving driving safety.

[0057] (2) The amount of brain activity may be measured in the dorsolateral prefrontal cortex of the driver's brain. For example, the amount of brain activity in the dorsolateral prefrontal cortex may be measured based on at least one of functional near-infrared spectroscopy, electroencephalography, magnetoencephalography, and electroencephalography. This allows the driver's individual visual cognitive ability to be determined based on the driver's brain activity. (3) The controller 16 may determine whether the driver understands the positional relationship of objects based on spatial vision rather than object vision based on the results of the brain activity measurement. If it is determined that the driver understands the positional relationship based on spatial vision rather than object vision, the controller 16 may control the visual information presentation device 12 to reduce the spatial range that the driver can see from the visual information presented by the visual information presentation device 12. This allows the visible range to be switched based on the results of the determination of the driver's visual cognitive ability based on the measurement of the driver's brain activity.

[0058] (4) By comparing the measurement result of brain activity with a predetermined discrimination threshold, it may be determined whether the driver understands the positional relationship of objects based on spatial vision rather than object vision. This makes it possible to determine whether reducing the visible range can improve safety. (5) The controller 16 may detect the distance between the vehicle and an obstacle around the vehicle. If the distance between the vehicle and the obstacle is less than the threshold despite the driver's brain activity increasing after the driver visually recognizes the visual information presented by the visual information presentation device 12, it may be determined that the driver understands the positional relationship based on spatial vision rather than object vision. This makes it possible to determine whether reducing the visible range can improve safety.

[0059] (6) The spatial range that the driver can see from the image presented by the display device may be reduced by reducing the area in which the image is displayed on the display screen of the display device that is the visual information presentation device 12, by blocking part of the image displayed on the display screen, or by increasing the magnification at which the display device displays the image. This allows the visible range to be changed to suit the visual perception ability of the individual driver.

[0060] (7) A portion of the image displayed on the display screen may be obscured by superimposing a pseudo image of a pillar or headlight. For example, if the display screen were a mirror, the pseudo image of the pillar or headlight may be superimposed at a position where the driver would see a mirror image of the pillar or headlight inside the vehicle. This reduces the visible range in a more natural way for the driver.

[0061] (8) The spatial range that the driver can see from the mirror image presented by the visual information presentation device 12 may be reduced by reducing the area on which the image is reflected or by blocking part of the mirror. This allows the visible range to be switched to suit the driver's individual visual perception ability. (9) If reducing the spatial range that the driver can see would prevent the driver from seeing obstacles around the vehicle that are necessary for driving, control of the visual information presentation device 12 to reduce the spatial range that the driver can see may be prohibited. This improves safety by presenting only the minimum necessary visual information about obstacles.

[0062] (10) The controller 16 may execute a process for determining whether the driver is viewing the visual information presentation device 12 based on the direction of the driver's line of sight and the three-dimensional position information of the visual information presentation device 12, and measure the amount of brain activity when the driver is viewing the visual information presentation device 12. This improves the accuracy of measuring the amount of brain activity of the driver in response to the visual information presented by the visual information presentation device 12.

[0063] All examples and conditional terms described herein are intended for educational purposes to aid the reader in understanding the present invention and the concepts provided by the inventor for the advancement of technology, and should be construed without limitation to the specifically described examples and conditions above, and the configuration of examples herein for illustrating the advantages and disadvantages of the present invention. Although the embodiments of the present invention have been described in detail, it should be understood that various changes, substitutions, and alterations can be made thereto without departing from the spirit and scope of the present invention.

[0064] 1...vehicle, 10...information presentation device, 11...surrounding environment sensor, 12...visual information presentation device, 13...brain activity sensor, 14...visual target sensor, 15...threshold database, 16...controller, 16a...processor, 16b...storage device, 30...brain activity analysis unit, 31...cognitive load calculation unit, 32...visual target determination unit, 33...visible range control unit

Claims

1. An information presentation method characterized in that a controller executes the following processes: measuring the brain activity of the driver in response to visual information about the vehicle's surroundings that is presented to the driver by a visual information presentation device; and controlling the spatial range that the driver can see from the visual information presented by the visual information presentation device based on the results of the brain activity measurement.

2. The information presentation method according to claim 1, characterized in that the amount of brain activity is measured in the dorsolateral prefrontal cortex of the driver's brain.

3. The information presentation method according to claim 2, characterized in that brain activity in the dorsolateral prefrontal cortex is measured based on at least one of functional near-infrared spectroscopy, electroencephalography, magnetoencephalography, or electroencephalography.

4. The information presentation method described in any one of claims 1 to 3, characterized in that the controller determines whether the driver understands the positional relationship of objects based on spatial vision rather than object vision based on the measurement results of the brain activity, and if it determines that the driver understands the positional relationship based on spatial vision rather than object vision, controls the visual information presentation device to reduce the spatial range that the driver can see from the visual information presented by the visual information presentation device.

5. The information presentation method described in claim 4, characterized in that the measurement results of the brain activity are compared with a predetermined discrimination threshold to determine whether the driver understands the positional relationship of objects based on spatial vision rather than object vision.

6. The information presentation method described in claim 4 or 5, characterized in that the controller detects the distance between the vehicle and an obstacle around the vehicle, and when the distance between the vehicle and the obstacle is less than a threshold value despite the driver's brain activity increasing after the driver views the visual information presented by the visual information presentation device, determines that the driver understands the positional relationship based on spatial vision rather than object vision.

7. An information presentation method according to any one of claims 4 to 6, characterized in that the spatial range visible to the driver from the image presented by the display device is reduced by reducing the area in which the image is displayed on the display screen of the visual information presentation device, or by blocking part of the image displayed on the display screen, or by increasing the magnification at which the display device displays the image.

8. The method of presenting information according to claim 7, characterized in that a portion of the image displayed on the display screen is obscured by superimposing a pseudo image of a pillar or headlist.

9. The information presentation method according to claim 8, characterized in that a pseudo image of a pillar or headlight is superimposed at a position where a mirror image of the pillar or headlight inside the vehicle would be visible to the driver if the display screen were a mirror.

10. An information presentation method as claimed in any one of claims 4 to 6, characterized in that the area of ​​the mirror that is the visual information presentation device reflects an image is reduced, or a portion of the mirror is blocked, thereby reducing the spatial range that the driver can see from the mirror image presented by the mirror.

11. An information presentation method as described in any one of claims 4 to 6, characterized in that, if reducing the spatial range visible to the driver would cause the driver to be unable to see obstacles necessary for driving among obstacles around the vehicle, control of the visual information presentation device to reduce the spatial range visible to the driver is prohibited.

12. The information presentation method described in any one of claims 1 to 10, characterized in that the controller executes a process to determine whether the driver is viewing the visual information presentation device based on the direction of the driver's line of sight and three-dimensional position information of the visual information presentation device, and measures the amount of brain activity when the driver is viewing the visual information presentation device.

13. An information presentation device comprising: a visual information presentation device that presents visual information about the surroundings of a vehicle to a driver; and a controller that executes a process of measuring the driver's brain activity in response to the visual information about the surroundings of the vehicle presented by the visual information presentation device; and a process of controlling the spatial range that the driver can see from the visual information presented by the visual information presentation device based on the results of the measurement of the brain activity.

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