Visual field measurement method and movable body

Abstract

To measure a visual field according to a situation.SOLUTION: A method for measuring a visual field of a subject, comprises: an arrangement step of arranging a target object at a position at a measurement target distance from the subject and arranging symbols at a plurality of positions around the target object; and an identification step of identifying the visual field of the subject on the basis of at which position of the plurality of positions the subject can visually recognize the symbol arranged there while the subject is looking at the target object.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a visual field measurement method and a moving object. [Background technology]

[0002] There is known a technology for providing driving assistance by utilizing the driver's visual field. Patent Document 1 describes a visual field test performed by irradiating the windshield with light. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-119428 Summary of the Invention [Problem to be solved by the invention]

[0004] The present inventors have found that a person's visual field may vary depending on the focal length of the eye. An object of some aspects of the present invention is to provide a technique for measuring visual field depending on the situation. [Means for solving the problem]

[0005] According to some embodiments, there is provided a method for measuring the visual field of a subject, the method comprising: a placement step of placing a target at a position at a measurement distance from the subject and placing symbols at multiple positions around the target; and an identification step of identifying the visual field of the subject based on which of the multiple positions the symbol placed at can be seen by the subject while looking at the target. [Effects of the Invention]

[0006] According to some embodiments, the visual field can be measured in a context-sensitive manner. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram illustrating an example configuration of a vehicle according to some embodiments. [Figure 2] FIG. 1 is a flow diagram illustrating an example of a perimetry method according to some embodiments. [Figure 3] FIG. 10 is a schematic diagram illustrating an example of a test case according to some embodiments. [Figure 4] FIG. 10 is a schematic diagram illustrating an example of a test case according to some embodiments. [Figure 5] 1 is a schematic diagram illustrating an example field of view according to some embodiments. [Figure 6] FIG. 10 is a diagram illustrating an example of visual field information according to some embodiments. [Figure 7] FIG. 1 is a flow diagram illustrating an example of a driving assistance method according to some embodiments. [Figure 8] 1A and 1B are schematic diagrams illustrating examples of driving assistance situations according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention as claimed, and not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more of the features described in the embodiments may be combined in any desired manner. Furthermore, the same reference numerals are used to designate identical or similar components, and redundant descriptions will be omitted.

[0009] <Control device and its application examples> FIG. 1 is a block diagram of a control device CNT according to some embodiments, and a schematic diagram of a vehicle V as an application example thereof. In FIG. 1, the vehicle V is shown in a plan view and a side view. The vehicle V of this embodiment is, as an example, a four-wheeled sedan-type passenger vehicle, and may be, for example, a parallel hybrid vehicle. The vehicle V is not limited to a four-wheeled passenger vehicle, but may also be a saddle-type vehicle (motorcycle, motor tricycle), or a large vehicle such as a truck or bus.

[0010] The control device CNT includes a controller 1, which is an electronic circuit that controls the vehicle V, including driving assistance for the vehicle V. The controller 1 includes multiple ECUs (Electronic Control Units). An ECU is provided, for example, for each function of the control device CNT. Each ECU includes a processor, such as a CPU (Central Processing Unit), a storage device such as a semiconductor memory, an interface with an external device, etc. The storage device stores programs executed by the processor and data used by the processor for processing, etc. The interface includes an input / output interface and a communication interface. Each ECU may include multiple processors, multiple storage devices, and multiple interfaces. The programs stored in the storage device may be installed in the control device CNT using a storage medium such as a CD-ROM and stored in the storage device. Additionally or alternatively, the programs stored in the storage device may be downloaded from an external server via wireless communication.

[0011] The controller 1 controls the drive (acceleration) of the vehicle V by controlling a power unit (power plant) 2. The power unit 2 is a traveling drive unit that outputs drive force to rotate the drive wheels of the vehicle V, and may include an internal combustion engine, a motor, and an automatic transmission. The motor can be used as a drive source to accelerate the vehicle V, and can also be used as a generator during deceleration, etc. (regenerative braking).

[0012] In this embodiment, the controller 1 controls the output of the internal combustion engine and the motor and shifts the gears of the automatic transmission in response to the driver's operation detected by the operation detection sensor 2a provided on the accelerator pedal AP and the operation detection sensor 2b provided on the brake pedal BP, and the vehicle speed of the vehicle V detected by the rotation speed sensor 2c. The automatic transmission is provided with a rotation speed sensor 2c that detects the rotation speed of the output shaft of the automatic transmission as a sensor that detects the running state of the vehicle V. The vehicle speed of the vehicle V can be calculated from the detection result of the rotation speed sensor 2c.

[0013] The controller 1 controls the braking (deceleration) of the vehicle V by controlling the hydraulic device 3. The driver's braking operation on the brake pedal BP is converted into hydraulic pressure in the brake master cylinder BM and transmitted to the hydraulic device 3. The hydraulic device 3 is an actuator that can control the hydraulic pressure of the hydraulic oil supplied to the brake devices 3a (e.g., disc brake devices) provided on each of the four wheels based on the hydraulic pressure transmitted from the brake master cylinder BM.

[0014] The controller 1 can control the braking of the vehicle V by controlling the driving of the solenoid valves and the like provided in the hydraulic device 3. The controller 1 can also configure an electric servo brake system by controlling the distribution of braking force by the brake device 3a and braking force by regenerative braking of the motor provided in the power unit 2. The controller 1 may also turn on the brake lamps 3b during braking.

[0015] The controller 1 controls the steering of the vehicle V by controlling the electric power steering device 4. The electric power steering device 4 includes a mechanism for steering the front wheels in response to the driver's driving operation (steering operation) with respect to the steering wheel ST. The electric power steering device 4 includes a drive unit 4a that generates a driving force (sometimes referred to as steering assist torque) for assisting the steering operation or for automatically steering the front wheels of the vehicle V. The drive unit 4a includes a motor as a drive source. The electric power steering device 4 also includes a steering angle sensor 4b that detects the steering angle, a torque sensor 4c that detects the steering torque borne by the driver (called steering burden torque, to be distinguished from steering assist torque), and the like.

[0016] The controller 1 controls an electric parking brake device 3c provided on the rear wheels of the vehicle V. The electric parking brake device 3c has a mechanism for locking the rear wheels. The controller 1 can control the electric parking brake device 3c to lock and unlock the rear wheels.

[0017] The controller 1 controls an information output device 5 that notifies the driver of information inside the vehicle. The information output device 5 includes, for example, a display device 5a that notifies the driver of information by image and / or an audio output device 5b that notifies the driver of information by audio. The display device 5a includes, for example, a display device provided on the instrument panel or a display device provided on the steering wheel ST. The display device 5a may also include a head-up display. The information output device 5 may notify the occupants of information by vibration or light.

[0018] The controller 1 receives instruction inputs from a passenger (e.g., the driver) via the input device 6. The input device 6 is arranged in a position operable by the driver, and includes, for example, a group of switches 6a through which the driver issues instructions to the vehicle V, and / or a turn signal lever 6b that activates a turn signal (blinker).

[0019] The controller 1 recognizes and determines the current position and course (attitude) of the vehicle V. In this embodiment, the vehicle V is provided with a gyro sensor 7a, a GNSS (Global Navigation Satellite System) sensor 7b, and a communication device 7c. The gyro sensor 7a detects the rotational motion (yaw rate) of the vehicle V. The GNSS sensor 7b detects the current position of the vehicle V. The communication device 7c wirelessly communicates with a server that provides map information and traffic information to acquire this information. Furthermore, the communication device 7c may read field of view information from a database 10. The field of view information is information used to estimate the field of view of the driver of the vehicle V. Details of the field of view information will be described later.

[0020] The controller 1 determines the route of the vehicle V based on the detection results of the gyro sensor 7a and the GNSS sensor 7b, and sequentially acquires map information related to the route from the server via the communication device 7c and stores it in a database 7d (storage device). The vehicle V may be provided with other sensors for detecting the state of the vehicle V, such as an acceleration sensor for detecting the acceleration of the vehicle V.

[0021] The controller 1 performs driving assistance for the vehicle V based on the detection results of various detection units provided in the vehicle V. The vehicle V is provided with surrounding detection units 8a to 8b, which are external sensors that detect the outside of the vehicle V (surrounding conditions), and interior detection units 9a to 9b, which are interior sensors that detect the conditions inside the vehicle (the conditions of the occupants (particularly the driver)). The controller 1 is able to grasp the surrounding conditions of the vehicle V based on the detection results of the surrounding detection units 8a to 8b, and perform driving assistance in accordance with the surrounding conditions. Furthermore, the controller 1 is able to determine, based on the detection results of the interior detection units 9a to 9b, whether the driver is performing the predetermined operational obligations imposed on the driver when driving assistance is performed.

[0022] The surroundings detection unit 8a is an imaging device that captures images in front of the vehicle V (hereinafter, sometimes referred to as the front camera 8a), and is attached, for example, to the inside of the passenger compartment of the windshield at the front of the roof of the vehicle V. The controller 1 can extract the contours of targets and lane markings (white lines, etc.) on the road by analyzing the images captured by the front camera 8a.

[0023] The surroundings detection unit 8b is a millimeter wave radar (hereinafter, may be referred to as radar 8b), and uses radio waves to detect targets around the vehicle V, and detect (measure) the distance to the target and the direction (azimuth) of the target relative to the vehicle V. In the example shown in FIG. 1, five radars 8b are provided: one in the center of the front of the vehicle V, one at each of the left and right corners of the front, and one at each of the left and right corners of the rear.

[0024] The surrounding detection unit installed in the vehicle V is not limited to the above configuration, and the number of cameras and the number of radars may be changed, or a lidar (Light Detection and Ranging: LIDAR) that detects targets around the vehicle V may be installed.

[0025] The in-vehicle detection unit 9a is an imaging device that captures images of the interior of the vehicle (hereinafter, sometimes referred to as in-vehicle camera 9a), and is attached, for example, to the inside of the vehicle cabin at the front of the roof of the vehicle interior V. In this embodiment, the in-vehicle camera 9a is a driver monitor camera that captures images of the driver (for example, the driver's eyes and face). The controller 1 can determine the driver's line of sight and facial direction by analyzing the image (image of the driver's face) captured by the in-vehicle camera 9a.

[0026] The in-vehicle detection unit 9b is a grip sensor that detects the driver's grip of the steering wheel ST (hereinafter, may be referred to as grip sensor 9b), and is provided, for example, on at least a part of the steering wheel ST. As the in-vehicle detection unit, a torque sensor 4c that detects the steering torque of the driver may be used.

[0027] <Visual field measurement method> A method for measuring a person's visual field according to some embodiments will be described with reference to Fig. 2. In the following description, a person whose visual field is being measured will be referred to as a subject, and a person measuring the visual field will be referred to as an measurer. The method of Fig. 2 may be performed for each of multiple subjects. Measurement of one subject's visual field may be performed by multiple measurers.

[0028] In the method of FIG. 2, the visual field of the subject is measured in one test case. To start the method of FIG. 2, the person being measured guides the subject to a fixed position at the measurement location. The subject does not move from this fixed position and remains in the same position while the visual field is being measured. In this specification, when an object is described as moving without specifying a reference, it means that the object moves relative to the ground. The subject may be standing upright or sitting in a chair or the like during the visual field measurement. Alternatively, the visual field of the subject may be measured while the subject is riding in a moving object such as a vehicle V. This allows the visual field of the subject to be measured in a situation similar to when the moving object is being driven. The moving object may be any moving object such as a car, a bicycle, an electric wheelchair, or the like.

[0029] In S201, the tester determines the values ​​of parameters to be used in the test case to be executed. The parameter values ​​may be set in advance for each test case. The parameters may include at least one of (1) the distance from the subject to the target, (2) the orientation of the target relative to the subject's torso, (3) the orientation of the subject's face relative to the subject's torso, (4) the color of the symbol, (5) the lighting environment in which the visual field measurement is performed, and (6) an indicator representing the number of traffic participants to be placed around the target. Any of these parameters may affect the subject's visual field. Each parameter will be described below.

[0030] (1) Distance from the subject to the target A target is an object that the subject keeps looking at while measuring the visual field. The subject focuses on the target while measuring the visual field. The target may be any object that the subject can focus on. The subject's visual field may vary depending on the subject's focal length. Therefore, the test case may specify the distance from the subject to the target. In the following description, the distance from the subject to the target is referred to as the measurement target distance. The position of the subject may be the position of any point on the subject, for example, the position between the subject's eyebrows. The position of the target may be the position of any point on the target, for example, the center of the target.

[0031] (2) The orientation of the target relative to the subject's torso The subject's field of view may vary depending on the orientation of the target relative to the subject's torso. Therefore, the test case may specify the orientation of the target relative to the subject's torso. The orientation of the target relative to the subject's torso may be determined by a combination of the elevation / depression angle and azimuth angle of the target relative to the front of the subject's torso. For example, the test case may specify that the target be placed directly in front of the subject's torso, or that the target be placed 45 degrees to the right of the subject's torso, or that the target be placed 45 degrees above the subject's torso.

[0032] (3) The direction of the subject's face relative to the subject's body The subject's field of view may vary depending on the orientation of the subject's face relative to their torso. Therefore, the test case may specify the orientation of the subject's face relative to their torso. The orientation of the subject's face relative to their torso may be defined by a combination of the elevation / depression angle and azimuth angle of the front of the face relative to the front direction of the subject's torso. For example, the test case may specify that the subject faces forward, or that the subject faces a 45-degree angle to the right, or that the subject faces a 45-degree angle upward.

[0033] The direction of the target relative to the subject's face is determined according to the relationship between the direction in which the target is placed relative to the subject's torso and the direction of the subject's face relative to the subject's torso. The subject directs their gaze in the direction of the target relative to their face. When the direction of the target relative to the subject's torso and the direction of the subject's face relative to the subject's torso coincide, the subject will look at the target with their pupils centered. When the direction of the target relative to the subject's torso and the direction of the subject's face relative to the subject's torso do not coincide, the subject will look at the target with their pupils shifted from the center.

[0034] (4) Symbol color During visual field measurement, symbols are placed around the target to identify positions that can be seen by the subject. The subject's visual field may vary depending on the color of the symbols. Therefore, the test case may specify the color of the symbols. The color of the symbols may be selected from multiple colors (e.g., black, red, blue, yellow, etc.).

[0035] (5) Light environment The field of view of the subject may vary depending on the lighting environment at the measurement location. Therefore, the test case may specify the lighting environment. The lighting environment may refer to the environment related to the amount of light, the position of the light source, the color (wavelength) of light, etc. Examples of lighting environments include daytime, nighttime, backlight, frontlight, and specific weather conditions (sunny, cloudy). The measurer may illuminate the measurement location with a light or other device to adjust the lighting environment.

[0036] (6) An index showing the number of traffic participants to be placed around the landmark. The field of view of the subject may vary depending on the number of traffic participants included in the field of view of the subject. Therefore, the test case may specify an index representing the number of traffic participants to be placed around the target. The traffic participants may include pedestrians, cyclists, vehicles, etc. The index representing the number of traffic participants may be the actual number of traffic participants or a category of the number of traffic participants (for example, four categories: 0, 1 to 5, 6 to 10, and 11 or more).

[0037] In S202, the person measuring places a target at a position specified by the parameter values ​​determined in S201. Specifically, the person measuring places the target at a position in a specified direction relative to the body of the person being measured and at a measurement target distance from the person being measured.

[0038] In S203, the measurer places a symbol at any position around the target. The symbol has the color determined in S201. The symbol may be a two-dimensional symbol (e.g., a circle, a square, a cross, a triangle, a specific character, etc.) or a three-dimensional symbol (e.g., a sphere, a rectangular solid, a cone, etc.). Furthermore, the measurer may place one or more traffic participants of the indices determined in S201 around the target.

[0039] In S204, the measurer instructs the subject to look at the target (i.e., to focus on the target). The measurer may instruct the subject on the direction of their face based on the parameter values ​​determined in S201. For example, the measurer may instruct the subject to look at the target while facing forward. The measurer then asks the subject whether they can see a symbol while looking at the target. When measuring central vision as the visual field, the measurer may ask whether they can see the presence of a symbol. When measuring functional visual field as the visual field, the measurer may ask whether they can see the type of symbol.

[0040] In S205, the measurer records the response from the subject (i.e., whether the symbol was visible or not) in relation to the position of the symbol. The position of the symbol may be defined by a combination of the elevation / depression angle and azimuth angle of the symbol relative to the direction in front of the measurer's torso, and the distance from the measurer's torso to the symbol. The position of the symbol may be the position of any one point on the symbol, for example, the center of the symbol.

[0041] In S206, the measurer determines whether to place the symbol in a different position and perform measurement. If it is determined that the symbol will be placed in a different position and measurement will be performed ("YES" in S206), the measurer repeats steps S203 to S205. If it is determined that the symbol will not be placed in a different position and measurement will not be performed ("NO" in S206), the measurer executes S207. In this way, the measurer places symbols in multiple positions around the target and determines whether the person being measured can see the symbols at each position.

[0042] In S207, the subject specifies the visual field based on the record made in S205, which has been executed one or more times. Specifically, the subject specifies the visual field as a three-dimensional area that includes the positions that the subject answered that they could see, but does not include the positions that the subject answered that they could not see.

[0043] In S208, the person measuring the visual field records the visual field information in the database 10. The visual field information includes the values ​​of the parameters used in measuring the visual field and the visual field identified in S207. The parameters may include at least one of (1) the distance from the person being measured to the target, (2) the color of the symbol, (3) the orientation of the person being measured's face relative to the torso during the measurement, (4) the direction of the person being measured's gaze relative to the face during the measurement, (5) the lighting environment in which the measurement was performed, and (6) an indicator representing the number of traffic participants located around the target.

[0044] The visual field may be measured for a single subject using multiple test cases. In this case, the method of FIG. 2 may be performed for each of the multiple test cases. The multiple test cases may specify different values ​​of parameters. For example, the subject may determine, for each of multiple measurement distances, the subject's visual field when a target is placed at a position at each of the measurement distances from the subject. The subject may determine, for each of multiple directions relative to the subject's torso, the subject's visual field when a target is placed in each of the directions relative to the subject's torso and the subject's face is directed in each of the directions. The subject may determine, for each of multiple directions relative to the subject's face, the subject's visual field when a target is placed in each of the directions relative to the subject's face and the subject's gaze is directed in each of the directions. The subject may determine, for each of multiple lighting environments, the subject's visual field in each of the lighting environments. The subject may determine, for each of multiple colors, the subject's visual field when a symbol is represented in each of the colors. The measurer may specify, for each of a plurality of indicators representing the number of traffic participants, the field of view of the subject to be measured when the traffic participants of each indicator are positioned.

[0045] An example of a test case will be described with reference to FIGS. 3 and 4. FIGS. 3(a) and 4(b) to 4(d) show the measurement location as seen from above the subject 300. FIGS. 3(b) and 4(a) show the field of view of the subject 300. In the example of FIG. 3, a symbol (a circle in the example of FIG. 3(b)) drawn on a board 301 is used as the target. The surface of the board 301 on which the symbol is drawn is, for example, a rectangle with sides of 1 to 2 m. The board 301 is held by a person standing on the ground 303. Alternatively, the board 301 may be placed on a stand. Alternatively, the symbol may be displayed on a display device instead of being drawn on the board 301. Furthermore, the symbol may be represented by the subject's body. For example, the symbol may represent a specific pose of the subject. The board 301 is placed at a measurement distance 304 from the subject 300. During the measurement of the visual field, the line of sight 305 of the subject 300 is directed toward the board 301 .

[0046] In the example of FIG. 3, symbols (triangles and squares in the example of FIG. 3(b)) that are placed around the target to identify positions visible to the subject are drawn on a board 302. The surface on which the symbols are drawn is, for example, a rectangle with sides of 1 to 2 m. The board 302 is held by an examiner standing on the ground 303. Alternatively, the board 302 may be placed on a stand. By displaying the symbols on the board 302, the visual field can be measured even in places without a power source. The symbols may be displayed on a display device instead of being drawn on the board 302. Furthermore, the symbols may be represented by the body of the examinee. For example, the symbol may represent a specific pose of the examinee. The symbol has a size that allows it to be visible to the examinee when it is within the subject's visual field. This allows the visual field to be measured without being affected by the subject's eyesight.

[0047] The symbols used to identify the visual field are selected randomly so that they are not predictable by the subject. The symbols may be hidden from the subject until the subject directs their gaze toward the target. For example, the subject may turn the board 302 upside down or cover the symbols on the board 302 with a cloth or the like.

[0048] 3, two symbols (two boards 302) are placed in one execution of S202. Alternatively, only one symbol may be placed in one execution of S202, or three or more symbols may be placed.

[0049] 3, two symbols (boards 302) are placed symmetrically around the target object. The two symbols (boards 302) are placed on the same normal plane as the target object (board 301) with respect to the line of sight 305. Alternatively, the symbols may be placed on a different normal plane from the target object (board 301) with respect to the line of sight 305.

[0050] In the example of Figure 3, the two symbols (boards 302) are placed at the same height from the ground 303 as the target (board 302). Alternatively, as shown in Figure 4(a), the height at which the symbols are placed may be different from the height at which the target is placed. The ground 303 is an example of a horizontal plane, and other horizontal planes may be used to measure height. The symbols may also be placed directly above the target.

[0051] In the test cases shown in Figures 4(b) and (c), the board 301 is placed at a position away from the direction 401 in front of the torso 300b of the person being measured 300. In the test case shown in Figure 4(b), the person being measured 300 is instructed to turn the face 300a toward the direction 401 in front of the torso 300b. Therefore, the person being measured 300 moves his / her pupils to direct the gaze direction 305 toward the symbol on the board 301. In the test case shown in Figure 4(c), the person being measured 300 is instructed to turn the face 300a toward the symbol on the board 301. Therefore, the person being measured 300 directs the gaze direction 305 of his / her face toward the symbol on the board 301.

[0052] In the test case shown in Fig. 4(d), three pedestrians 402 are placed around the board 301 as traffic participants. The pedestrians 402 may walk around freely or remain in the same position during the field of view measurement. Traffic participants other than pedestrians may also be placed, or no traffic participants may be placed as shown in Fig. 3(b).

[0053] Figure 5 shows an example of a field of view obtained through an experiment by the inventors. Figure 5(a) shows a field of view 501 seen from above the head of the person being measured 300. Figure 5(b) shows a field of view 501 seen from the side of the person being measured 300. The field of view 501 has a shape formed by a cone portion 501a with the person being measured 300 at its apex and a cylindrical portion 501b extending from the bottom surface of the cone portion 501a.

[0054] FIG. 6 shows an example of visual field information 600 recorded in the database 10 in S208 of FIG. 2. In FIG. 6, the visual field information 600 is recorded in table format, but the visual field information 600 may be recorded in other formats. The visual field information 600 has one entry for each execution of the method of FIG. 2. In the visual field information 600, information in columns 601 to 605 is recorded in association with each other. Column 601 stores identification information for identifying each test. Column 602 stores identification information for identifying the subject. Column 603 stores attribute values ​​of the subject. The subject may record attribute values ​​that may affect the visual field as part of the visual field information 600. Such attributes may include, for example, at least one of age category, visual acuity category, whether or not the subject wears glasses, whether or not the subject wears contact lenses, and whether or not the subject suffers from a specific disease (e.g., glaucoma). The age category may be divided, for example, in increments of 10 years, or at other granularities. The visual acuity classification may be divided in increments of 0.1, for example, or may be divided at other granularities. Column 604 stores the values ​​of the parameters used to measure the visual field. Column 605 stores the visual field identified in S207.

[0055] The administrator of the database 10 may combine multiple entries in the field of view information 600 to generate a new entry. For example, the administrator may combine multiple entries having the same attribute (column 603) value and parameter (column 604) value to generate a new entry. Columns 603 and 604 of this new entry store information before the combination. Column 605 of this new entry stores a field of view (e.g., union, intersection, etc.) that represents the field of view of the multiple entries before the combination. The newly generated entry may be used as general-purpose field of view information related to a specific value of the attribute. Furthermore, the administrator may combine multiple entries having the same parameter (column 604) value to generate a new entry. Column 604 of this new entry stores information before the combination. Column 605 of this new entry stores a field of view (e.g., union, intersection, etc.) that represents the field of view of the multiple entries before the combination. The newly generated entry may be used as general-purpose field of view information that is independent of attributes.

[0056] <Driving assistance method> A driving assistance method executed by the vehicle V will be described with reference to FIG. 7. Each step in FIG. 7 may be executed by the control device CNT. Specifically, each step in FIG. 7 may be performed by a processor of the control device CNT executing a program loaded into the memory of the control device CNT. Alternatively, some or all of the steps in FIG. 7 may be executed by a dedicated integrated circuit such as an ASIC (Application Specific Integrated Circuit). The method in FIG. 7 may be started in response to an instruction to start driving assistance from the driver of the vehicle V (hereinafter simply referred to as the driver), or may be started automatically in response to the power of the vehicle V being turned on. The method in FIG. 7 may be executed by a moving body other than the vehicle V (for example, an airplane, a ship, etc.).

[0057] In S701, the control device CNT acquires the visual field information 600 from the database 10. If the control device CNT can identify the driver and the visual field information 600 regarding this driver is recorded in the database 10, the control device CNT may acquire the visual field information 600 regarding this driver. In other cases, the control device CNT may acquire general-purpose visual field information 600.

[0058] In S702, the control device CNT starts measuring parameters for estimating the field of view of the driver of the vehicle V. After this, the control device CNT continues to measure parameters. The parameters may include at least one of (1) a distance from the driver to a target located in the driver's line of sight, (2) a color of traffic participants located around the target, (3) a direction of the driver's face relative to the driver's torso, (4) a direction of the driver's line of sight relative to the driver's face, (5) a light environment around the vehicle V, and (6) an index representing the number of traffic participants located around the target.

[0059] The distance from the driver to a target located in the driver's line of sight is measured, for example, based on the detection results of the front camera 8a and radar 8b. The color of traffic participants located around the target located in the driver's line of sight is measured, for example, based on the detection results of the front camera 8a. The direction of the driver's face relative to his torso is measured, for example, based on the detection results of the in-vehicle camera 9a. The direction of the driver's line of sight relative to his face is measured, for example, based on the detection results of the in-vehicle camera 9a. The light environment around the vehicle V is measured, for example, based on the detection results of the front camera 8a and radar 8b. An index representing the number of traffic participants located around the target located in the driver's line of sight is measured, for example, based on the detection results of the front camera 8a and radar 8b.

[0060] In S703, the control device CNT estimates the field of view associated with the value of the parameter measured in S702 in the field of view information 600 as the driver's field of view. If there is no field of view information 600 having a value matching the value of the parameter measured in S702, the control device CNT may identify the field of view information 600 having a value closest to the value of the parameter measured in S702. The field of view included in the field of view information 600 has the shape of the field of view 501 described in FIG. 5. Therefore, the control device CNT estimates the driver's field of view to have a shape formed by a cone portion with the driver at the apex and a cylindrical portion extending from the base of this cone portion.

[0061] In S704, the control device CNT provides driving assistance based on the field of view estimated in S703. The driving assistance may include notifying the driver of the presence of a traffic participant. For example, the control device CNT may notify the driver of the presence of a traffic participant located outside the driver's field of view when the traffic participant is likely to collide with the vehicle V. Alternatively or in addition, the control device CNT may notify the driver of the presence of a traffic participant when the traffic participant is located within the driver's field of view for a predetermined period of time but the driver is not looking at it.

[0062] In S705, the control device CNT determines whether the value of the parameter whose measurement was started in S702 has changed. If it is determined that the value of the parameter has changed ("YES" in S705), the control device CNT transitions the process to S706, and otherwise ("NO" in S705) repeats S705. In this way, the control device CNT waits until the value of the parameter has changed.

[0063] In S706, the control device CNT estimates the field of view associated with the changed value of the parameter as the field of view of the driver, in the same manner as in S703. In this way, the control device CNT updates the field of view used for driving assistance every time the value of the parameter changes.

[0064] An example of a driving assistance situation will be described with reference to FIG. 8 . Assume that a driver 801 of a vehicle V is driving while looking at a preceding vehicle 802. In this case, the target located in the driver's line of sight is the preceding vehicle 802. Therefore, the control device CNT measures the distance from the driver 801 to the preceding vehicle 802. The control device CNT may also determine that the driver's face is facing forward with respect to the driver's torso and that the driver's line of sight is facing forward with respect to the driver's face. The control device CNT may also determine that the light environment around the vehicle V is sunny during the day and that the only traffic participant around the preceding vehicle 802 is a pedestrian 803. Furthermore, the control device CNT may measure the color of the pedestrian's clothing. The control device CNT may estimate the field of view of the driver 801 based on the values ​​of these parameters and provide driving assistance based on this field of view. The color of the traffic participants may differ for each traffic participant. Therefore, the control device CNT may provide driving assistance for each traffic participant based on the field of view estimated for each traffic participant.

[0065] <Summary of the embodiment> [Item 1] A method for measuring a visual field (501) of a subject (300), comprising: an arrangement step (S202) of arranging a target (301) at a position at a measurement target distance (304) from the subject and arranging symbols (302) at a plurality of positions around the target; and a determination step (S207) of determining the subject's field of view based on which of the multiple positions a symbol placed at can be seen by the subject while looking at the target. This item allows you to measure your field of view depending on the situation. [Item 2] 2. The method according to claim 1, wherein the specifying step includes specifying, for each of a plurality of measurement target distances, the field of view of the subject when the target is placed at a position at each of the measurement target distances from the subject. This item allows for the measurement of visual field in individual situations. [Item 3] 3. The method according to claim 1, wherein the symbol has a size that allows the symbol to be visible to the subject when present within the subject's field of vision. According to this item, the visual field can be measured with high accuracy regardless of the subject's visual acuity. [Item 4] 4. The method according to any one of items 1 to 3, wherein the plurality of positions include positions at different heights from a horizontal plane (303) of the target object. This item allows you to measure your field of view in three-dimensional space. [Item 5] The method according to any one of items 1 to 4, wherein the specifying step includes specifying, for each of a plurality of directions relative to the torso (300b) of the person being measured, the field of view of the person being measured when the target is positioned in each direction relative to the torso of the person being measured and the face (300a) of the person being measured is facing the each direction. This item allows for the measurement of visual field in individual situations. [Item 6] The method according to any one of items 1 to 5, wherein the specifying step includes specifying, for each of a plurality of directions relative to the face of the person being measured, the field of view of the person being measured when the target is positioned in each direction relative to the face of the person being measured and the line of sight of the person being measured is directed in each direction. This item allows for the measurement of visual field in individual situations. [Item 7] 7. The method according to any one of items 1 to 6, wherein the specifying step includes specifying the field of view to be measured in each of a plurality of light environments. This item allows for the measurement of visual field in individual situations. [Item 8] 8. The method according to any one of items 1 to 7, wherein the specifying step includes specifying, for each of a plurality of colors, the visual field of the subject when the symbol is represented in each of the colors. This item allows for the measurement of visual field in individual situations. [Item 9] The step of placing includes placing one or more traffic participants (402) around the landmark; The method according to any one of items 1 to 8, wherein the specifying step includes specifying, for each of a plurality of indicators representing the number of the one or more traffic participants, the field of view of the object to be measured when the traffic participant of each indicator is positioned. This item allows for the measurement of visual field in individual situations. [Item 10] The method further includes a recording step (S208) of recording the field of view identified in the identifying step in a database (10) in association with the value of the parameter used in the measurement, The parameters are: The distance from the subject to the target; The color of the symbol; the orientation of the subject's face relative to their torso during measurement; The direction of the subject's gaze relative to the face during measurement; The lighting environment in which the measurements were taken, an indicator representing the number of traffic participants arranged around the landmark; 10. The method according to any one of items 1 to 9, comprising at least one of: This item makes available the field of view measured for each individual situation. [Item 11] 11. The method according to any one of items 1 to 10, wherein the specifying step includes specifying the field of view of the subject while the subject is on board a moving body (V). This item allows for the measurement of the field of view in situations where driving assistance is provided. [Item 12] A moving body (V), an acquisition means for acquiring visual field information from a database (10); A measuring means for measuring parameters for estimating the field of view of the driver (801) of the vehicle; and an estimation means for estimating a field of view (501) associated with the value of the parameter in the field of view information as the field of view of the driver, The parameters are: A distance from the driver to a target located in the driver's line of sight; the color of the traffic participants located around the target; the orientation of the driver's face relative to their torso; A direction of the driver's line of sight with respect to the face; A light environment around the moving body; an indicator representing the number of traffic participants located around the target; A mobile object including at least one of the following: According to this item, the field of view used for driving assistance can be estimated with high accuracy.

[0066] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention. [Explanation of symbols]

[0067] V Vehicle, CNT Control Device, 300 Subject, 801 Driver

Claims

1. A method for measuring a subject's visual field, comprising: an arrangement step of arranging a target at a position at a measurement target distance from the subject and arranging symbols at a plurality of positions around the target; and a determination step of determining the subject's field of view based on which of the multiple positions a symbol placed at can be seen by the subject while looking at the target.

2. 2. The method according to claim 1, wherein the specifying step includes specifying, for each of a plurality of measurement target distances, the field of view of the subject when the target is placed at a position at each of the measurement target distances from the subject.

3. The method of claim 1 , wherein the symbol has a size that allows it to be seen by the subject when present within the subject's field of vision.

4. The method of claim 1 , wherein the plurality of locations includes locations at different heights above a horizontal plane than the target.

5. 2. The method of claim 1, wherein the identifying step includes identifying, for each of a plurality of directions relative to the torso of the subject, the field of view of the subject when the target is positioned in each direction relative to the torso of the subject and the face of the subject is facing the each direction.

6. 2. The method according to claim 1, wherein the specifying step includes specifying, for each of a plurality of directions relative to the face of the person being measured, the field of view of the person being measured when the target is positioned in each of the directions relative to the face of the person being measured and the person's line of sight is directed in each of the directions.

7. The method of claim 1 , wherein the step of identifying includes identifying the field of view to be measured in each of a plurality of lighting environments.

8. The method according to claim 1 , wherein the specifying step includes specifying, for each of a plurality of colors, the visual field of the subject when the symbol is displayed in each of the colors.

9. the arranging step includes arranging one or more traffic participants around the landmark; 2. The method of claim 1, wherein the identifying step includes identifying, for each of a plurality of indicators representing the number of the one or more traffic participants, the field of view of the object to be measured when the traffic participant of each indicator is positioned.

10. The method further comprises a recording step of recording the visual field identified in the identifying step in a database in association with the values ​​of the parameters used in the measurement, The parameters are: The distance from the subject to the target; The color of the symbol; the orientation of the subject's face relative to their torso during measurement; The direction of the subject's gaze relative to the face during measurement; The lighting environment in which the measurements were taken, an indicator representing the number of traffic participants arranged around the landmark; The method of claim 1 , comprising at least one of:

11. The method according to claim 1 , wherein the specifying step includes specifying the field of view of the subject while the subject is on board a moving object.

12. A mobile object, an acquisition means for acquiring visual field information from a database; a measuring means for measuring a parameter for estimating the field of view of the driver of the moving body; an estimation means for estimating a field of view associated with the parameter value in the field of view information as the field of view of the driver; The parameters are: A distance from the driver to a target located in the driver's line of sight; the color of the traffic participants located around the target; the orientation of the driver's face relative to their torso; A direction of the driver's line of sight with respect to the face; A light environment around the moving body; an indicator representing the number of traffic participants located around the target; A mobile object including at least one of the following:

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