Automobile data recorder and control method thereof

Abstract

An automobile data recorder according to the present invention is provided with: a camera for generating an image of the front of a vehicle to which the automobile data recorder is mounted; a recognition unit that recognizes, on the basis of the image, a dividing line of a road on which the vehicle travels; a determination unit that determines whether or not the vehicle is about to deviate from the travel lane on the basis of the amount of change per unit time of the distance between the automobile data recorder and the division line; and an alarm unit that outputs an alarm when it is determined that the vehicle is about to deviate from the travel lane.

Description

TECHNICAL FIELD

[0001] The present application relates to a vehicle-mounted camera and a control method thereof. BACKGROUND

[0002] Techniques are known that alert a driver to a vehicle's imminent departure from a lane. Such an alert is referred to as a lane departure alert. In the technique described in Patent Literature 1, it is determined whether a vehicle will depart from a travel lane, based on a reference line made in accordance with the state of a lane, and an estimated position of the vehicle after a predetermined time.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2018-43539 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] In place of a lane departure alert by a vehicle, or on the basis of a lane departure alert by a vehicle, it is considered to perform a lane departure alert using a vehicle-mounted camera. The installation position of a vehicle-mounted camera can differ from vehicle to vehicle, and therefore it is difficult to determine the positional relationship between a vehicle and a lane and perform a lane departure alert on the basis of an image generated by a vehicle-mounted camera alone. Some aspects of the present application provide a technique for performing a vehicle departure alert using an image generated by a vehicle-mounted camera.

[0008] MEANS FOR SOLVING THE PROBLEMS

[0009] According to some embodiments, a vehicle-mounted camera is provided that includes a camera that generates an image of the front of a vehicle on which the vehicle-mounted camera is mounted, an identification mechanism that identifies a division line of a road on which the vehicle is traveling, based on the image, a determination mechanism that determines whether the vehicle will depart from a travel lane, based on the amount of change per unit time in the distance between the vehicle-mounted camera and the division line, and an alert mechanism that outputs an alert in the case where it is determined that the vehicle will depart from the travel lane.

[0010] EFFECTS OF THE INVENTION

[0011] According to some embodiments, a vehicle departure alert can be performed using an image generated by a vehicle-mounted camera.

[0012] Other features and advantages of the present application will be apparent from the following description, taken in conjunction with the accompanying drawings, mentioned herein. Furthermore, in the accompanying drawings, like reference numerals designate like elements throughout the several views. BRIEF DESCRIPTION OF DRAWINGS

[0013] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the application and, together with the description, serve to explain the principles of the application.

[0014] Figure 1 is a block diagram illustrating a configuration example of a vehicle to which a plurality of embodiments are applied.

[0015] Figure 2 is a block diagram illustrating a hardware configuration example of a car navigation device to which a plurality of embodiments are applied.

[0016] Figure 3 is a flowchart illustrating an action example of a car navigation device to which a plurality of embodiments are applied.

[0017] Figure 4 is a schematic diagram illustrating an image example generated by a car navigation device to which a plurality of embodiments are applied.

[0018] Figure 5 is a schematic diagram illustrating an alarm condition example to which a plurality of embodiments are applied. DETAILED DESCRIPTION

[0019] Hereinafter, embodiments will be described with reference to the drawings. Note that the following embodiments do not limit the technical scope of the application. In addition, the following embodiments do not limit the combinations of features described in the embodiments. Two or more features described in the embodiments can be combined. In addition, the same portions in the drawings are denoted with the same reference numerals, and repeated explanation is omitted.

[0020] Reference Signs List Figure 1 A configuration example of a vehicle V to which a part of the embodiments is applied will be described. Figure 1 is a block diagram of a control device CNT and a schematic diagram of a vehicle V as an application example. In Figure 1 , a schematic of the vehicle V is indicated by a plan view and a side view. The vehicle V of the present embodiment is a four-wheel passenger car of a sedan type as one example, and can be, for example, a parallel hybrid vehicle. The vehicle V is not limited to the four-wheel passenger car, and can be a straddle-type vehicle (automobile two-wheeler, automobile three-wheeler), or a large vehicle such as a truck, a bus, or the like.

[0021] The control device CNT includes a controller 1 that is a circuit that executes control of the vehicle V including drive assist of the vehicle V. The controller 1 is provided with a plurality of ECUs (Electronic Control Units). The ECUs are provided, for example, in accordance with each function of the control device CNT. Each ECU includes a processor typified by a CPU (Central Processing Unit), a storage device such as a semiconductor memory, an interface with an external device, and the like. In the storage device, a program executed by the processor, data used for processing by the processor, and the like are stored. In the interface, an input-output interface, a communication interface are included. Each ECU can be provided with a plurality of processors, a plurality of storage devices, and a plurality of interfaces. The program stored in the storage device can be installed in the control device CNT by using a storage medium such as a CD-ROM, and stored in the storage device. On this basis or alternatively, the program stored in the storage device can be downloaded from an external server through wireless communication.

[0022] The controller 1 controls driving (acceleration) of the vehicle V by controlling a power unit (power device) 2. The power unit 2 is a travel drive portion that outputs a driving force that rotates a driving wheel of the vehicle V, and can include an internal combustion engine, a motor, and an automatic transmission. The motor can be used as a driving source for accelerating the vehicle V, and can also be used as a generator (regenerative brake) at the time of deceleration, and the like.

[0023] In the case of the present embodiment, the controller 1 controls the output of the internal combustion engine, the motor, or shifts the gear of the automatic transmission in accordance with the driving operation of the driver detected by an operation detection sensor 2a provided to an accelerator pedal AP, an operation detection sensor 2b provided to a brake pedal BP, the vehicle speed of the vehicle V detected by a rotation speed sensor 2c, and the like. The rotation speed sensor 2c is provided to the automatic transmission, and detects the rotation speed of an output shaft of the automatic transmission as a sensor that detects the travel 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.

[0024] The controller 1 controls braking (deceleration) of the vehicle V by controlling a hydraulic device 3. The brake operation of the brake pedal BP by the driver is converted into hydraulic pressure in a 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 working oil supplied to brake devices 3a (for example, disc brake devices) respectively provided to the four wheels, based on the hydraulic pressure transmitted from the brake master cylinder BM.

[0025] The controller 1 can control the braking of the vehicle V by performing drive control of a solenoid valve or the like provided in the hydraulic device 3. In addition, the controller 1 controls distribution of the braking force based on the brake device 3a and the braking force based on the regenerative braking of the motor provided in the power unit 2, and thus can also constitute an electric servo brake system. The controller 1 can also cause the brake light 3b to be lit at the time of braking.

[0026] 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 that steers the front wheels in accordance with a steering operation (steering operation) of the driver on the steering wheel ST. The electric power steering device 4 has a drive unit 4a that exerts an assist for the steering operation or exerts a driving force (sometimes expressed as a steering assist torque) for automatically steering the front wheels of the vehicle V. The drive unit 4a has a motor as a driving source. In addition, the electric power steering device 4 includes a steering angle sensor 4b that detects a steering angle, a torque sensor 4c that detects a steering torque (referred to as a steering undertaken torque, distinguished from the steering assist torque) undertaken by the driver, and the like.

[0027] The controller 1 controls an electric parking brake device 3c provided to the rear wheels of the vehicle V. The electric parking brake device 3c has a mechanism that locks the rear wheels. The controller 1 can control locking and unlocking of the rear wheels based on the electric parking brake device 3c.

[0028] The controller 1 controls an information output device 5 that reports information to the inside of the vehicle. The information output device 5 includes, for example, a display device 5a that reports information to the driver by an image, and / or a sound output device 5b that reports information to the driver by a sound. The display device 5a includes, for example, a display device provided to an instrument panel, a display device provided to the steering wheel ST. In addition, the display device 5a can also include a head-up display. The information output device 5 can also report information to the occupant by vibration, light.

[0029] The controller 1 accepts an instruction input from an occupant (for example, a driver) via an input device 6. The input device 6 is disposed at a position operable by the driver, and includes, for example, a switch group 6a by which the driver instructs the vehicle V, and / or a winker lever 6b that operates a winker (turn signal).

[0030] The controller 1 recognizes and determines the current position and the travel route (attitude) of the vehicle V. In the case of the present embodiment, a gyro sensor 7a, a GNSS (Global Navigation Satellite System) sensor 7b, and a communication device 7c are provided in the vehicle V. The gyro sensor 7a detects the rotational movement (yaw rate) of the vehicle V. The GNSS sensor 7b detects the current position of the vehicle V. In addition, the communication device 7c performs wireless communication with a server that provides map information and traffic information and acquires these information. In the case of the present embodiment, the controller 1 determines the travel route of the vehicle V on the basis of the detection results of the gyro sensor 7a and the GNSS sensor 7b, and sequentially acquires map information relating to the travel route from the server via the communication device 7c, and then stores the map information relating to the travel route in a data base 7d (storage device). Other sensors for detecting the state of the vehicle V, such as an acceleration sensor that detects the acceleration of the vehicle V, can also be provided in the vehicle V.

[0031] The controller 1 performs driving assistance of the vehicle V on the basis of the detection results of various detection units provided in the vehicle V. In the vehicle V, there are provided outside sensors, i.e., surrounding detection units 8a to 8b, that detect the outside (surrounding situation) of the vehicle V, and in-vehicle sensors, i.e., in-vehicle detection units 9a to 9b, that detect the situation in the vehicle (state of the occupant (particularly, the driver)). The controller 1 can grasp the surrounding situation of the vehicle V on the basis of the detection results of the surrounding detection units 8a to 8b, and perform driving assistance in accordance with the surrounding situation. In addition, the controller 1 can determine whether or not the driver is performing a predetermined action obligation required of the driver at the time of performing the driving assistance on the basis of the detection results of the in-vehicle detection units 9a to 9b.

[0032] The surrounding detection unit 8a is a photographing device (hereinafter sometimes referred to as a front camera 8a) that photographs the front of the vehicle V, for example, is installed in the vehicle V on the in-cabin side of the front window of the front portion of the roof. The photographing device generates an image of a subject by photographing the subject. The controller 1 can extract the outline of a target object and extract the division line (white line or the like) of the lane on the road by analyzing the image generated by the front camera 8a.

[0033] The surrounding detection unit 8b is a millimeter wave radar (hereinafter sometimes referred to as a radar 8b) that detects a target object in the surroundings of the vehicle V using an electric wave, and detects (measures) the distance to the target object and the direction (bearing) of the target object with respect to the vehicle V. In the case of the present embodiment, the radar 8b is provided in the front portion of the vehicle V. The controller 1 can grasp the surrounding situation of the vehicle V on the basis of the detection results of the radar 8b. Figure 1In the illustrated example, five radars 8b are provided, one radar 8b is provided at the center of the front portion of the vehicle V, one radar 8b is provided at each of the corners of the left and right of the front portion, and one radar 8b is provided at each of the corners of the left and right of the rear portion.

[0034] The surrounding detection unit provided to the vehicle V is not limited to the above-described configuration, and the number of cameras and the number of radars can be changed, and an optical radar (LIDAR: Light Detection and Ranging) that detects a target object around the vehicle V can be provided.

[0035] The in-vehicle detection unit 9a is an imaging device (hereinafter sometimes referred to as an in-vehicle camera 9a) that images the inside of the vehicle, for example, is installed on the inside of the cabin at the front portion of the roof of the vehicle V. In the case of the present embodiment, the in-vehicle camera 9a is a driver monitor camera that images the driver (for example, the eyes, the face of the driver). The controller 1 can determine the orientation of the line of sight, the face of the driver by analyzing the image (the face image of the driver) generated by the in-vehicle camera 9a.

[0036] The in-vehicle detection unit 9b is a holding sensor (hereinafter sometimes referred to as a holding sensor 9b) that detects the holding of the steering wheel ST of the driver, for example, is provided to 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 can also be used.

[0037] A dashcam 100 is installed in the vehicle V. The dashcam 100 records the image of the front of the vehicle V generated by the camera 203 (image generation unit) of the dashcam 100. Figure 2 ) of the dashcam 100. The dashcam 100 is installed, for example, on the inside of the cabin of the front window at the front portion of the roof of the vehicle V. The installation position (particularly, the position in the vehicle width direction) of the dashcam 100 can be various depending on the type of the vehicle V, the preference of the user. In some embodiments, the dashcam 100 detects the situation that the vehicle V is about to deviate from the travel lane by analyzing the image of the front of the vehicle V, and outputs an alarm to the user of the dashcam 100. The travel lane can be the lane in which the vehicle is traveling. The user of the dashcam 100 can be, for example, the occupant of the vehicle V, particularly, the driver of the vehicle V. In the following description, the user of the dashcam 100 is simply referred to as the user. The alarm that the vehicle V is about to deviate from the travel lane can also be referred to as a lane deviation alarm.

[0038] The driving assistance of the vehicle V to the driver includes, for example, acceleration / deceleration assistance, lane maintenance assistance, and lane change assistance. The acceleration / deceleration assistance is a driving assistance (ACC: Adaptive Cruise Control) in which the controller 1 automatically controls the power unit 2 and the hydraulic device 3 on the basis of the detection result of the surrounding detection unit 8, the map information, thereby automatically controlling the acceleration / deceleration of the vehicle V within a predetermined vehicle speed. In the ACC, in the presence of a preceding vehicle, the acceleration / deceleration of the vehicle V can be performed in such a manner as to maintain the inter-vehicle distance from the preceding vehicle. With the ACC, the driver is relieved of the operation burden of the acceleration / deceleration operation (operation of the accelerator pedal AP and the brake pedal BP).

[0039] The lane maintenance assistance is a driving assistance (LKAS: Lane Keeping Assist System) in which the controller 1 automatically controls the electric power steering device 4 on the basis of the detection result of the surrounding detection unit 8, the map information, thereby causing the vehicle V to be maintained on the inner side of the lane. With the LKAS, the driver is relieved of the operation burden of the steering operation (operation of the steering wheel ST) in the straight running of the vehicle V.

[0040] The lane change assistance is a driving assistance (ALC: Auto Lane Changing, ALCA: Active Lane Change Assist) in which the controller 1 automatically controls the power unit 2, the hydraulic device 3, and the electric power steering device 4 on the basis of the detection result of the surrounding detection unit 8, the map information, thereby changing the travel lane of the vehicle V to an adjacent lane. The ALC is a lane change assistance based on a system request, and the ALCA is a lane change assistance based on a passenger request. As the system request, for example, there can be cited a case where the lane change of the vehicle V is requested by a navigation system that guides the route of the vehicle V to a destination, or a case where the lane change is requested regardless of the route guidance in the presence of a preceding vehicle. In the case of the passenger request, the driver instructs the lane change by operating an input device (for example, the direction indicator lever 6b). The driver is relieved of the operation burden of the acceleration / deceleration operation and the steering operation of the vehicle V at the time of the lane change by the ALC or the ALCA.

[0041] As other examples of the driving assistance control, there can be cited, for example, a collision mitigation brake that assists in collision avoidance with a target object (for example, a pedestrian, another vehicle, or an obstacle) on the road by controlling the hydraulic device 3, an ABS function, a traction control, and / or a posture control of the vehicle V.

[0042] Reference Signs List Figure 2 A hardware configuration example of the dashcam 100 will be described. The dashcam 100 can include, for example, Figure 2The illustrated constituent elements. The car navigation device 100 can not include Figure 2 part of the illustrated constituent elements, and can include Figure 2 constituent elements not illustrated. For example, the car navigation device 100 can further include a global positioning satellite system (GNSS) sensor, an accelerometer.

[0043] The processor 201 controls the overall action of the car navigation device 100. The processor 201 can be constituted by, for example, a central processing unit (CPU). The processor 201 can be a single processor, or a collection of a plurality of processors.

[0044] The memory 202 stores programs and data used for the action of the car navigation device 100. The memory 202 can also record an image (particularly, a moving image) of the front of the vehicle V generated by the camera 203. The memory 202 can be constituted by, for example, a read only memory (ROM), a random access memory (RAM). The memory 202 can be a single memory, or a collection of a plurality of memories.

[0045] The camera 203 is a device for taking an image of the front of the vehicle V. The camera 203 takes an image of the front of the vehicle V, thereby generating an image of the front of the vehicle V. The car navigation device 100 is installed to the vehicle V in a manner that the taking range of the camera 203 becomes the front of the vehicle V. The car navigation device 100 can further include a camera for taking an image of the rear of the vehicle V.

[0046] The communication device 204 is a device for communicating with a device different from the car navigation device 100. For example, it can be that the communication device 204 is able to communicate with the communication device 7c of the vehicle V. Alternatively or in addition thereto, it can be that the communication device 204 is able to communicate with a portable device (for example, a smartphone) held by a user. The communication based on the communication device 204 can be wireless communication, or wired communication. For example, the communication based on the communication device 204 can be near distance wireless communication like Bluetooth (registered trademark).

[0047] The input device 205 is a device for receiving an instruction from a user of the car navigation device 100. The input device 205 can be constituted by a physical button, a dial switch, a touch panel, or any combination of these. The instruction to the car navigation device 100 from the user can be acquired from another device through the communication device 204 on the basis of or instead of the input device 205.

[0048] The output device 206 is a device for outputting information to the user. The output device 206 can be constituted by a display device such as a liquid crystal display, an acoustic device such as a speaker, a lamp, an indicator, or any combination of these. The information output to the user can be performed in other apparatuses through the communication device 204 on the basis of or instead of the output device 206.

[0049] Referring to Figure 3 An example of the operation of the vehicle-mounted camera 100 will be described. In some embodiments, the vehicle-mounted camera 100 can have a function of performing a lane departure warning. That is, the vehicle-mounted camera 100 can output a warning to the user in a case where the vehicle V is about to depart from a travel lane. Figure 3 The steps of the method of Figure 3 Some or all of the steps of the method of Figure 3 The method of Figure 3 The method of

[0050] In S301, the processor 201 acquires an image of the front of the vehicle V generated by the camera 203. The camera 203 photographs the front of the vehicle V at a predetermined interval. Figure 3 The photographing of the front of the vehicle V is repeated in the execution of the method of

[0051] In S302, the processor 201 identifies a lane in which the vehicle V travels (i.e., a travel lane) by analyzing the image acquired in S301. Referring to Figure 4 An example of the operation for identifying the travel lane will be described. Figure 4 is an example of an image 400 of the front of the vehicle V generated by the camera 203. The processor 201 identifies division lines 401 to 404 of a road in which the vehicle V travels by performing image recognition on the image 400. The division line refers to a line drawn on a road in order to indicate the configuration of the road, and includes, for example, a lane center line, a lane boundary line, a lane outer side line, and the like. In Japan, the division line is a white or yellow line. The white division line can also be referred to as a white line. In Japan, the white line is a solid line or a broken line, and the yellow division line is a solid line.

[0052] Next, the processor 201 identifies the division line among the division lines 401 to 404 included in the image 400, which makes an angle with the traveling direction of the vehicle V within a predetermined range (for example, within 30 degrees). For example, the processor 201 converts the image 400 into an overhead image 410. The overhead image 410 is an image of a portion of the road included in the image 400, which is at least observed from directly above the vehicle V to the vicinity of the car recorder 100. A position 411 of the lower edge center of the overhead image 410 can correspond to the position of the car recorder 100 in the road. The generation of the overhead image 410 can be performed using an existing method. Thereafter, the processor 201 identifies the division line (in the example of the division lines 401 to 404) in the overhead image 410, which makes an angle with the traveling direction of the vehicle V within a predetermined range (for example, within 30 degrees). The processor 201 can set the longitudinal direction of the overhead image 410 as the traveling direction of the vehicle V. Figure 4 In the example of the division lines 401 to 404, the processor 201 identifies the division line 401 as the right side division line. In addition, the processor 201 identifies the division line 402 as the left side division line. In this way, the right side division line refers to the division line, which is located to the right of the car recorder 100, which makes an angle within a predetermined angle with respect to the traveling direction of the vehicle V, and which does not include other division lines between the car recorder 100. The left side division line refers to the division line, which is located to the left of the car recorder 100, which makes an angle within a predetermined angle with respect to the traveling direction of the vehicle V, and which does not include other division lines between the car recorder 100.

[0053] Thereafter, the processor 201 identifies the division line among the division lines 401 to 404 included in the image 400, which makes an angle with the traveling direction of the vehicle V within a predetermined range (for example, within 30 degrees). For example, the processor 201 converts the image 400 into an overhead image 410. The overhead image 410 is an image of a portion of the road included in the image 400, which is at least observed from directly above the vehicle V to the vicinity of the car recorder 100. A position 411 of the lower edge center of the overhead image 410 can correspond to the position of the car recorder 100 in the road. The generation of the overhead image 410 can be performed using an existing method. Thereafter, the processor 201 identifies the division line (in the example of the division lines 401 to 404) in the overhead image 410, which makes an angle with the traveling direction of the vehicle V within a predetermined range (for example, within 30 degrees). The processor 201 can set the longitudinal direction of the overhead image 410 as the traveling direction of the vehicle V. Figure 4 In the example of the division lines 401 to 404, the processor 201 identifies the division line 401 as the right side division line. In addition, the processor 201 identifies the division line 402 as the left side division line. In this way, the right side division line refers to the division line, which is located to the right of the car recorder 100, which makes an angle within a predetermined angle with respect to the traveling direction of the vehicle V, and which does not include other division lines between the car recorder 100. The left side division line refers to the division line, which is located to the left of the car recorder 100, which makes an angle within a predetermined angle with respect to the traveling direction of the vehicle V, and which does not include other division lines between the car recorder 100. Figure 4 In the example of the division lines 401 to 404, the processor 201 identifies the division line 401 as the right side division line. In addition, the processor 201 identifies the division line 402 as the left side division line. In this way, the right side division line refers to the division line, which is located to the right of the car recorder 100, which makes an angle within a predetermined angle with respect to the traveling direction of the vehicle V, and which does not include other division lines between the car recorder 100. The left side division line refers to the division line, which is located to the left of the car recorder 100, which makes an angle within a predetermined angle with respect to the traveling direction of the vehicle V, and which does not include other division lines between the car recorder 100.

[0054] Thereafter, the processor 201 identifies the division line among the division lines 401 to 404 included in the image 400, which makes an angle with the traveling direction of the vehicle V within a predetermined range (for example, within 30 degrees). For example, the processor 201 converts the image 400 into an overhead image 410. The overhead image 410 is an image of a portion of the road included in the image 400, which is at least observed from directly above the vehicle V to the vicinity of the car recorder 100. A position 411 of the lower edge center of the overhead image 410 can correspond to the position of the car recorder 100 in the road. The generation of the overhead image 410 can be performed using an existing method. Thereafter, the processor 201 identifies the division line (in the example of the division lines 401 to 404) in the overhead image 410, which makes an angle with the traveling direction of the vehicle V within a predetermined range (for example, within 30 degrees). The processor 201 can set the longitudinal direction of the overhead image 410 as the traveling direction of the vehicle V.

[0055] If the processor 201 cannot identify the right dividing line but recognizes the left dividing line, it may identify the area to the right of the left dividing line as the driving lane. If the processor 201 cannot identify the left dividing line but recognizes the right dividing line, it may identify the area to the left of the right dividing line as the driving lane. If the processor 201 cannot identify either the left dividing line or the right dividing line, it may determine that the vehicle V is not traveling in a lane and repeat S301 and S302 without transitioning to S303.

[0056] Back to Figure 3 As explained above, in S303, processor 201 determines whether the time during which vehicle V has been continuously traveling in the same lane has reached a threshold time. If processor 201 determines that vehicle V has been continuously traveling in the same lane for a threshold time ("Yes" in S303), processing proceeds to S304. If processor 201 determines that vehicle V has not been continuously traveling in the same lane for a threshold time ("No" in S303), processing proceeds to S301. The advantages of this step will be described later.

[0057] In S304, the processor 201 calculates the distance between the driving recorder 100 and the dividing line, and stores it in the memory 202 in association with the current time. The dividing line used for calculating the distance is denoted as the reference dividing line. The reference dividing line can be the dividing line identified in S302, which forms an angle with the traveling direction of the vehicle V within a predetermined range (e.g., within 30 degrees) ( Figure 4 In the example, any one of the dividing lines 401 to 404). In particular, the reference dividing line may be the right dividing line or the left dividing line. The dividing line located near the driving recorder 100 can be identified with high precision, and the distance measurement accuracy is also high, so a dividing line like this is used as a reference dividing line, thereby enabling a lane departure warning to be performed with high precision. The reference dividing line may be one or more. The distance between the driving recorder 100 and the reference dividing line may be the shortest distance between the position 411 in the overhead image 410 and the reference dividing line (e.g., the dividing line 401).

[0058] In S305, the processor 201 determines whether or not an alarm condition is satisfied. The processor 201 transfers the process to S306 in a case where it is determined that the alarm condition is satisfied (YES in S305), and transfers the process to S301 in a case where it is determined that the alarm condition is not satisfied (NO in S305). The alarm condition refers to a condition that should be satisfied in order for the car recorder 100 to make an alarm facing the user. For example, the alarm condition can include a case where it is determined that the vehicle V is about to deviate from the travel lane 405. For example, the processor 201 can determine whether or not the vehicle V is about to deviate from the travel lane on the basis of the amount of change per unit time of the distance between the car recorder 100 and the reference dividing line, and determine that the alarm condition is satisfied in a case where it is determined that the vehicle V is about to deviate.

[0059] In S306, the processor 201 outputs an alarm facing the user. The alarm can be made in a manner that the user can recognize that the vehicle V is about to deviate from the lane. The output of the alarm can be made by any response. For example, the processor 201 can output an alarm (e.g., an alarm sound) from the output device 206 (e.g., a speaker) of the car recorder 100. The processor 201 can also request the control device CNT of the vehicle V to make an alarm facing the user through the communication device 204. In accordance with a case where the request has been received, the control device CNT can display a screen including an alarm message using the information output device 5, or can broadcast an alarm message through a sound. The processor 201 can end the alarm in accordance with a case where a certain time has elapsed, or can end the alarm in accordance with an instruction of the user.

[0060] Reference Signs List Figure 5 A specific example of the alarm condition will be described. It is assumed that the vehicle V is traveling on the travel lane 405 with the dividing line 401 as the right dividing line and the dividing line 402 as the left dividing line. It is assumed that the front end of the vehicle is located at the position 501 at the time T1, and the front end of the vehicle V is located at the position 502 at the time T2 after that. First, a case where the processor 201 uses only the right dividing line (the dividing line 401) as the reference dividing line will be described. The same applies to a case where the processor 201 uses only the left dividing line (the dividing line 402) as the reference dividing line.

[0061] At time T1, the processor 201 calculates the distance 503 between the vehicle-mounted camera 100 and the dividing line 401 by executing S304, which is stored in the memory 202 in association with the time T1. At a later time T2, the processor 201 calculates the distance 504 between the vehicle-mounted camera 100 and the dividing line 401 by executing S305 again, which is stored in the memory 202 in association with the time T2. Thereafter, in S305, the processor 201 calculates the amount of change in the distance between the vehicle-mounted camera 100 and the dividing line 401 per unit time. The unit time is a value that is determined in advance, for example, and is stored in the memory 202. The unit time can be, for example, 0.5 seconds, 1 second, 5 seconds, or the like. In the following description, the time from the time T1 to the time T2 is assumed to coincide with the unit time. Therefore, the processor 201 sets the value obtained by subtracting the distance 503 from the distance 504 as the amount of change in the distance between the vehicle-mounted camera 100 and the dividing line 401 per unit time. The amount of change becomes positive if the vehicle V moves away from the dividing line 401, and becomes negative if the vehicle V approaches the dividing line 401.

[0062] The processor 201 can determine that the vehicle V is about to deviate from the travel lane 405 by exceeding the right dividing line (the dividing line 401) when the amount of change is less than a predetermined value (for example, -30 cm). The processor 201 can determine that the vehicle V is about to deviate from the travel lane 405 by exceeding the left dividing line (the dividing line 402) when the amount of change is greater than a predetermined value (for example, 30 cm). The processor 201 can determine that the vehicle V is not about to deviate from the travel lane 405 when the amount of change is within a predetermined range (for example, -30 cm to 30 cm).

[0063] It is considered that the amount of change in the distance between the vehicle-mounted camera 100 and the reference dividing line per unit time coincides or almost coincides with the amount of change in the distance between the vehicle V and the reference dividing line per unit time, regardless of the position at which the vehicle-mounted camera 100 is installed in the vehicle V. Therefore, as described above, it is possible to appropriately perform a lane deviation warning using the image generated by the vehicle-mounted camera 100 based on the amount of change in the distance between the vehicle-mounted camera 100 and the reference dividing line per unit time.

[0064] Next, a case where the processor 201 uses both the right dividing line (dividing line 401) and the left dividing line (dividing line 402) as the reference dividing line will be described. At time T1, the processor 201 calculates the distance 503 between the vehicle-mounted camera 100 and the dividing line 401 and the distance 505 between the vehicle-mounted camera 100 and the dividing line 402 by executing S304, and stores them in association with time T1 in the memory 202. At a later time T2, the processor 201 calculates the distance 504 between the vehicle-mounted camera 100 and the dividing line 401 and the distance 506 between the vehicle-mounted camera 100 and the dividing line 402 by executing S305 again, and stores them in association with time T2 in the memory 202. Thereafter, in S305, the processor 201 calculates the amount of change in the distance between the vehicle-mounted camera 100 and the dividing line 401 per unit time (hereinafter, right side change amount) and the amount of change in the distance between the vehicle-mounted camera 100 and the dividing line 402 per unit time (hereinafter, left side change amount).

[0065] The processor 201 can determine that the vehicle V is about to deviate from the travel lane 405 by exceeding the right dividing line (dividing line 401) in a case where the right side change amount is smaller than a predetermined value (for example, -30 cm). The processor 201 can determine that the vehicle V is about to deviate from the travel lane 405 by exceeding the left dividing line (dividing line 402) in a case where the left side change amount is smaller than a predetermined value (for example, -30 cm). The processor 201 can determine that the vehicle V is not about to deviate from the travel lane 405 in a case where the right side change amount is larger than a predetermined value (for example, -30 cm) and the left side change amount is larger than a predetermined value (for example, -30 cm).

[0066] For example, in a case where the width of the travel lane 405 is large, the distance between the vehicle-mounted camera 100 and the reference dividing line can be large regardless of whether the vehicle V is not about to deviate from the travel lane 405 or not. As described above, by using both the right dividing line and the left dividing line as the reference dividing line, it is possible to suppress the case where the lane deviation warning is made excessively.

[0067] Reference Signs Figure 3 As described above, the processor 201 does not make a warning based on the amount of change per unit time in the distance between the vehicle-mounted camera 100 and the reference dividing line in a case where the time during which the vehicle V continues to travel in the same lane is smaller than a threshold time. The position of the vehicle V in the vehicle width direction within the travel lane can swing immediately after the vehicle V starts traveling in a new lane. Therefore, by executing S303, it is possible to suppress the case where the lane deviation warning is made excessively. The threshold time is a value decided in advance, for example, stored in the memory 202. The threshold time can be, for example, 30 seconds, 1 minute, 5 minutes, or the like.

[0068] The alarm condition can be based not only on the amount of change in the distance between the car navigation device 100 and the reference division line per unit time as described above, but also on the case where the distance between the car navigation device 100 and the reference division line is within a threshold distance. That is, the processor 201 can output an alarm in the case where the distance between the car navigation device 100 and the reference division line is within a threshold distance. The threshold distance is a value that is decided in advance, for example, stored in the memory 202. The threshold distance can be, for example, 30 cm, 50 cm, or the like. In order to suppress an excessive lane departure alarm, the threshold distance can be a value set assuming that the car navigation device 100 is installed in the vehicle V at the position closest to the reference division line.

[0069] <Summary of Embodiments>

[0070] [Item 1]

[0071] A car navigation device (100) includes:

[0072] The car navigation device (100) includes:

[0073] a camera (203) that generates an image (400) of the front of a vehicle (V) in which the car navigation device is installed;

[0074] an identification mechanism (201) that identifies a division line (401 to 404) of a road on which the vehicle is traveling, based on the image;

[0075] a determination mechanism (201) that determines whether the vehicle is about to deviate from a travel lane (405), based on an amount of change in a distance (503 to 506) between the car navigation device and the division line per unit time; and

[0076] an alarm mechanism (201) that outputs an alarm in the case where it is determined that the vehicle is about to deviate from the travel lane.

[0077] According to this item, a vehicle deviation alarm can be performed using an image generated by a car navigation device.

[0078] [Item 2]

[0079] The car navigation device according to item 1, wherein:

[0080] the alarm mechanism does not perform the alarm based on the amount of change in the distance between the car navigation device and the division line per unit time in the case where a time during which the vehicle continuously travels on the same lane is less than a threshold time.

[0081] According to this item, an excessive vehicle deviation alarm can be suppressed.

[0082] [Item 3]

[0083] The drive recorder according to Item 1 or 2, wherein

[0084] The identification mechanism uses at least one of the following division lines as the division line:

[0085] a right division line (401) that is located on the right side of the drive recorder, is located within a predetermined angle with respect to the traveling direction of the vehicle, and does not include other division lines between the drive recorder and the vehicle; and

[0086] a left division line (402) that is located on the left side of the drive recorder, is located within a predetermined angle with respect to the traveling direction of the vehicle, and does not include other division lines between the drive recorder and the vehicle.

[0087] According to this item, the vehicle deviation warning can be performed with high accuracy.

[0088] [Item 4]

[0089] The drive recorder according to any one of Items 1 to 3, wherein

[0090] The warning mechanism further outputs a warning in a case where the distance between the drive recorder and the division line is within a threshold distance.

[0091] According to this item, the vehicle deviation warning can be performed with high accuracy.

[0092] [Item 5]

[0093] A control method of a drive recorder (100) having a camera (203) that generates an image (400) of the front of a vehicle (V), wherein

[0094] The control method has the following steps:

[0095] identifying a division line (401 to 404) of a road on which the vehicle travels, on the basis of the image (S302);

[0096] determining whether the vehicle is about to deviate from a travel lane (405) on the basis of an amount of change per unit time of a distance (503 to 506) between the drive recorder and the division line (S305); and

[0097] outputting a warning in a case where it is determined that the vehicle is about to deviate from the travel lane (S306).

[0098] According to this item, the vehicle deviation warning can be performed using the image generated by the drive recorder.

[0099] The application is not limited to the above-described embodiments, and various modifications and changes can be made within the scope of the application.

Claims

1. A drive recorder, wherein the drive recorder is provided with: a camera that generates an image of a front of a vehicle on which the drive recorder is mounted; an identification mechanism that identifies a dividing line of a road on which the vehicle is traveling, based on the image; a determination mechanism that determines whether the vehicle is about to deviate from a travel lane, based on an amount of change per unit time of a distance between the drive recorder and the dividing line; and an alarm mechanism that outputs an alarm in a case where it is determined that the vehicle is about to deviate from the travel lane.

2. The drive recorder according to claim 1, wherein the alarm mechanism does not perform the alarm based on the amount of change per unit time of the distance between the drive recorder and the dividing line, in a case where a time during which the vehicle continuously travels on the same lane is less than a threshold time.

3. The drive recorder according to claim 1 or 2, wherein the identification mechanism uses at least one of the following dividing lines as the dividing line: a right dividing line that is located on a right side of the drive recorder, is located within a predetermined angle with respect to a traveling direction of the vehicle, and does not include other dividing lines between the drive recorder and the right dividing line; and a left dividing line that is located on a left side of the drive recorder, is located within a predetermined angle with respect to the traveling direction of the vehicle, and does not include other dividing lines between the drive recorder and the left dividing line.

4. The drive recorder according to any one of claims 1 to 3, wherein the alarm mechanism further outputs an alarm in a case where the distance between the drive recorder and the dividing line is within a threshold distance.

5. A control method of a drive recorder that has a camera that generates an image of a front of a vehicle, wherein the control method has the following steps: identifying a dividing line of a road on which the vehicle is traveling, based on the image; determining whether the vehicle is about to deviate from a travel lane, based on an amount of change per unit time of a distance between the drive recorder and the dividing line; and outputting an alarm in a case where it is determined that the vehicle is about to deviate from the travel lane. ​ ​

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