Anti-fog system

Abstract

To properly control the output of a heater in a defogging system that suppresses fogging of a window with heating by the heater.SOLUTION: A defogging system X for a camera 10 that captures the vehicle exterior through a predetermined visual area R set to a window 6 of a vehicle 1 comprises: a heater 31 which heats the visual area; a vehicle exterior temperature sensor 40 which detects the temperature of the outside of a passenger compartment 3 as the vehicle exterior temperature; and a control device 26 which controls the heater on the basis of the vehicle exterior temperature acquired by the vehicle exterior temperature sensor. The control device determines whether or not a given ice melting condition is satisfied on the basis of the vehicle exterior temperature detected by the vehicle exterior temperature sensor, and, when the ice melting condition is not satisfied, suppresses the output of the heater compared to a case where the ice melting condition is satisfied.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an anti-fog system for reducing fogging on vehicle windows. [Background technology]

[0002] Conventionally, vehicles equipped with an imaging device that captures an image of an exterior space of the vehicle through a window from inside the vehicle are known. Such vehicles are sometimes provided with a defogging system for suppressing fogging of the window to prevent fogging of the window from interfering with imaging by the imaging device. The defogging system includes a defogging device (e.g., a heating device for heating the window) that suppresses fogging of the window and a control device that controls the defogging device.

[0003] For example, Patent Document 1 discloses a mobile body equipped with a monitoring device capable of monitoring the surrounding environment of the mobile body through a translucent window member, a heating device for heating a portion of the window member within the monitoring area of ​​the monitoring device, an air conditioning device for conditioning the air inside the vehicle cabin, and a control device for controlling the operation of the heating device.

[0004] The heating device includes a first heating section and a second heating section provided downstream of the first heating section in the direction of conditioned air from the air conditioner. When the air conditioner is in operation, the control device drives the second heating section with priority over the first and second heating sections. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-152324 Summary of the Invention [Problem to be solved by the invention]

[0006] Such an anti-fogging system controls the heater to prevent fogging on the inside of the window. However, if the outside of the window freezes over, it becomes difficult to capture images using a camera (photographing device).

[0007] The inventors of the present application therefore came up with the idea of ​​using a heater in the defogging system to remove ice that has adhered to the exterior surface of the window, but when using a heater in the defogging system, there is a risk that the heater will not provide enough heat or that the heater will provide too much heat, which could put stress on the components that make up the window.

[0008] In view of the above background, the present invention aims to provide an anti-fogging system that prevents fogging on windows by heating the windows with a heater, and to promote de-icing of the windows with the heater and appropriately control the heater output. By suppressing fogging on the windows, situations in which vehicle driving control based on the image capture results from the image capture device cannot be performed are reduced, and ultimately, traffic safety is further improved, contributing to the development of a sustainable transportation system. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, one aspect of the present invention is an anti-fogging system (X) for a camera (10) that photographs the outside of a vehicle (1) through a predetermined viewing area (R) set on a window (6), the system comprising: a heater (31) that heats the viewing area; an outside temperature sensor (40) that detects the temperature outside the passenger compartment (3) as the outside temperature; and a control device (26) that controls the heater based on the outside temperature acquired by the outside temperature sensor, the control device determining whether or not predetermined de-icing conditions are met based on the outside temperature detected by the outside temperature sensor, and suppressing the output of the heater when the de-icing conditions are not met compared to when the conditions are met.

[0010] According to this aspect, when the de-icing condition is not satisfied, the heater output is limited. As a result, when the de-icing condition is satisfied, the heater output is not limited, which promotes de-icing of the window by the heater. Also, when the de-icing condition is not satisfied, excessive heater output can be prevented. Therefore, the heater output can be appropriately controlled.

[0011] In the above aspect, preferably, the device further includes a camera internal temperature sensor (41) that detects the internal temperature of the camera as the camera internal temperature, and the control device sets a threshold value (Th) based on the outside vehicle temperature detected by the outside vehicle temperature sensor, and when the camera internal temperature detected by the camera internal temperature sensor is low, determines that the de-icing condition is met.

[0012] According to this aspect, it is possible to appropriately set the ice-melting conditions for limiting the heater output.

[0013] In the above aspect, the threshold value is preferably set to be maintained or to increase as the outside temperature decreases.

[0014] According to this aspect, the threshold value can be set appropriately.

[0015] In the above aspect, preferably, the vehicle further includes an interior temperature sensor (42) that acquires the temperature inside the vehicle compartment as the interior temperature, and the control device sets a threshold value (Th) based on the outside temperature detected by the outside temperature sensor, and when the inside temperature acquired by the interior temperature sensor is lower than the threshold value, determines that the de-icing condition is met.

[0016] According to this aspect, it is possible to appropriately set the ice-melting conditions for limiting the heater output.

[0017] In the above aspect, preferably, the threshold value is set to be maintained or to decrease as the outside temperature decreases.

[0018] According to this aspect, the threshold value can be set appropriately.

[0019] In the above aspect, preferably, the control device is capable of applying a voltage pulse that repeatedly turns on and off to the heater, and changes the output of the heater by changing the duty ratio of the voltage pulse.

[0020] According to this aspect, the heater output can be appropriately controlled by a simple method. [Effects of the Invention]

[0021] According to the above aspect, in an anti-fogging system that suppresses fogging of a window by heating with a heater, it is possible to promote thawing of the window by the heater and to appropriately control the output of the heater. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a perspective view showing a vehicle according to an embodiment of the present invention; [Figure 2] FIG. 1 is a perspective view showing a front camera and its peripheral portion according to an embodiment of the present invention; [Figure 3] FIG. 1 is a functional block diagram illustrating an anti-fogging system according to an embodiment of the present invention. [Figure 4] Control device block diagram [Figure 5] Authenticity table according to the first embodiment [Figure 6] Output control process flow chart [Figure 7] Authenticity table according to the second embodiment [Figure 8] Graph showing modified examples of determination information DETAILED DESCRIPTION OF THE INVENTION

[0023] <Vehicle> First, a vehicle 1 equipped with an anti-fogging system X according to one embodiment of the present invention will be described with reference to the drawings. An arrow Fr in Figs. 1 and 2 indicates the front of the vehicle 1.

[0024] <<First Embodiment>> 1, vehicle 1 is a four-wheeled vehicle, or what is known as an automobile. Vehicle 1 may be an electric vehicle using only an electric motor as a drive source, or may be a hybrid vehicle equipped with an electric motor and an engine as drive sources.

[0025] Vehicle 1 has a vehicle body 2 that forms its exterior shape. Vehicle body 2 has a shape that is long in the front-to-rear direction of the vehicle. An interior space SP1 is formed inside vehicle body 2, and a passenger compartment 3 that accommodates occupants is provided in the center of interior space SP1 in the front-to-rear direction. The passenger compartment 3 is provided with, for example, a plurality of front seats 4 (driver's seat, passenger seat) and a plurality of rear seats 5 arranged behind the front seats 4. Note that in this embodiment, two rows of seats are provided in the front and rear, but in other embodiments, there may be only one row of seats in the front and rear, or three or more rows of seats in the front and rear.

[0026] A front windshield 6 (an example of a window) is provided in the front part of the vehicle body 2, in front of the front seats 4. The front windshield 6 is configured by a panel (window member) made of glass. In other embodiments, the front windshield 6 may be made of a transparent material other than glass (for example, a transparent resin). A rear window 7 is provided in the rear part of the vehicle body 2, behind the rear seats 5. A plurality of side doors 8 are provided on both sides of the vehicle body 2, beside the front seats 4 and rear seats 5, and a side window 9 is provided above each side door 8.

[0027] As shown in FIGS. 1 and 2, a front camera 10 (an example of an imaging device) is provided at the upper rear of the windshield 6. The front camera 10 is an imaging device that images (photographs) an exterior space SP2 (in this embodiment, the space in front of the vehicle 1) from an interior space SP1 through the windshield 6. The front camera 10 is, for example, a digital camera that uses a solid-state imaging element such as a CCD or CMOS. The front camera 10 includes a lens 10A that converges light incident from the front through the windshield 6, and a sensor (not shown) that converts the light converged by the lens 10A into an electrical signal.

[0028] 2, the front camera 10 is attached to the inner surface of the windshield 6 via a bracket 11. The bracket 11 has a fixing frame 12 fixed to the inner surface of the windshield 6 and a hood 13 protruding from the fixing frame 12 toward the rear lower side (inside the vehicle). When viewed from the front of the vehicle 1, the fixing frame 12 overlaps with black ceramic 6A printed on the surface of the windshield 6 facing inside the vehicle.

[0029] The hood 13 is provided behind the windshield 6 (inside the vehicle). The hood 13 is installed to prevent, for example, light reflected by an object in the vehicle interior space SP1 from being reflected by the windshield 6 and thereby capturing an object in the vehicle interior space SP1 in an image captured by the front camera 10. The hood 13 may be provided with a stray light shield (SLS) to prevent light reflected by the hood 13 from entering the front camera 10. The hood 13 defines the lower edge of a space (hereinafter referred to as a visual field space S) through which light entering the front camera 10 from the vehicle exterior space SP2 passes. The front camera 10 captures an image of the vehicle exterior space SP2 through a portion of the windshield 6 located within the visual field space S of the front camera 10 (hereinafter referred to as a visual field region R).

[0030] 3, the vehicle 1 includes a propulsion device 14, a braking device 15, a steering device 16, an HMI (Human Machine Interface) 17, a navigation device 18, an air conditioning device 20, a heating device 21, an external sensor 23, a vehicle sensor 24, and a control device 26. The heating device 21, the vehicle sensor 24, and the control device 26 constitute an anti-fogging system X for the vehicle 1.

[0031] The propulsion device 14 is a device that applies driving force to the vehicle 1. The propulsion device 14 includes, for example, an internal combustion engine such as a gasoline engine or a diesel engine and / or an electric motor.

[0032] The braking device 15 is a device that applies braking force to the vehicle 1. The braking device 15 includes, for example, a brake caliper that presses a pad against a brake rotor, and an electric cylinder that supplies hydraulic pressure to the brake caliper.

[0033] The steering device 16 is a device that changes the steering angle of the wheels. The steering device 16 includes, for example, a rack and pinion mechanism that steers the wheels, and an electric motor that drives the rack and pinion mechanism.

[0034] The HMI 17 is a device that notifies the occupant of various information and receives input operations from the occupant. The HMI 17 includes, for example, a power switch for switching the power state of the vehicle 1, a touch panel, a sound generating device (speaker), a sound acquiring device (microphone), and the like.

[0035] The navigation device 18 is a device that provides route guidance to the destination of the vehicle 1. The navigation device 18 includes an input device that accepts input operations from the occupant. This input device may be configured as a part of the HMI 17, or may be provided separately from the HMI 17.

[0036] The navigation device 18 stores map information of the area in which the vehicle 1 travels. The navigation device 18 identifies the current position (latitude and longitude) of the vehicle 1 based on GNSS signals (e.g., GPS signals) received from artificial satellites. The navigation device 18 sets a driving route from the departure point (e.g., current position) of the vehicle 1 to the destination based on the map information, the current position of the vehicle 1, and the destination of the vehicle 1 input by the occupant to the input device.

[0037] The navigation device 18 is connected to various servers 30 via a network N such as the Internet. Each server 30 is a computer equipped with a CPU, memories such as ROM and RAM, and storage devices such as HDD and SSD. Each server 30 provides corresponding information in response to a request from the navigation device 18. The server 30 to which the navigation device 18 is connected may include a weather server 30A that provides weather forecast information for the driving route in response to a request from the navigation device 18. The weather forecast information includes the weather, temperature, and wind speed predicted for each point on the driving route. Furthermore, the weather forecast information may also include the amount of solar radiation, temperature, humidity, etc. predicted for each point on the driving route.

[0038] The air conditioner 20 is configured as a so-called car air conditioner that cools, heats, and ventilates the interior space SP1. The air conditioner 20 cools the air using the heat of vaporization of a refrigerant and sends the air into the interior space SP1, thereby cooling the interior space SP1. The air conditioner 20 heats the air using heat generated by the propulsion device 14, etc., and sends the air into the interior space SP1, thereby heating the interior space SP1. Alternatively, the air conditioner 20 may be configured to heat the interior space SP1 by using an electric heater, a heat pump, etc., and sending the air into the interior space SP1.

[0039] The air conditioner 20 includes a duct connected to the interior space SP1 and the exterior space SP2, an evaporator and a heater core installed in the duct, a blower fan that generates an air flow in the duct, and an electric motor that drives the blower fan. The air conditioner 20 is configured to be able to change the set temperature, air volume (the rotation speed of the blower fan), and air conditioning mode.

[0040] The heating device 21 is a device that heats the windshield 6 to suppress fogging of the windshield 6, and includes a heater 31 for performing the heating. In this embodiment, the heater 31 heats the viewing area R of the windshield 6 to suppress fogging of the viewing area R. In this way, suppressing fogging of the viewing area R (i.e., the portion of the windshield 6 required for the front camera 10 to capture an image of the vehicle exterior space SP2) prevents the front camera 10 from being unable to capture an image of the vehicle exterior space SP2.

[0041] The heater 31 is composed of a heating wire 33. As shown in Fig. 2, the heating wire 33 is fixed to the inner surface of the windshield 6 and is arranged along the outer periphery of the visual field space S of the front camera 10, specifically, along the outer edge of the visual field area R. Note that in other embodiments, the heating wire 33 may be built into the windshield 6 or may be fixed to the bracket 11.

[0042] The external sensor 23 is a sensor that detects objects (such as obstacles on the roadway of the vehicle 1, lane markings, and preceding vehicles) present in the vehicle exterior space SP2. As shown in FIG. 3, the external sensor 23 includes the front camera 10, a sonar 38, and an exterior camera 39 that captures images of the left and right sides and rear of the vehicle 1 through the window.

[0043] The vehicle sensor 24 is a sensor for acquiring information related to temperature and the like that may cause stress on the windshield 6, and detects the state of the interior space SP1 and the exterior space SP2, etc. The vehicle sensor 24 is connected to the control device 26 and outputs the detection results to the control device 26.

[0044] The vehicle sensor 24 includes an exterior temperature sensor 40 provided on the vehicle body 2 and an interior temperature sensor 41 provided inside the front camera 10. The vehicle sensor 24 may further include an interior temperature sensor 42 provided inside the vehicle compartment.

[0045] The exterior temperature sensor 40 (also referred to as an exterior air temperature sensor) detects the temperature of the exterior space SP2 (an example of the state of the exterior space SP2; hereinafter referred to as "exterior temperature"). The exterior temperature sensor 40 may be disposed, for example, near the front bumper or the front grille. The exterior temperature sensor 40 may be configured, for example, by a thermistor whose resistance value changes depending on the exterior temperature (outside air temperature). The exterior temperature sensor 40 may be configured by a resistance temperature detector or a thermocouple instead of a thermistor.

[0046] The camera internal temperature sensor 41 detects the temperature inside the front camera 10 (hereinafter referred to as the camera internal temperature). The camera internal temperature sensor 41 is preferably configured as a thermistor whose resistance value changes with temperature changes. The camera internal temperature sensor 41 is preferably provided on a circuit board on which a solid-state imaging element is provided, and is preferably configured and arranged so that its resistance changes according to the temperature of the memory or the solid-state imaging element, for example. The camera internal temperature sensor 41 may be configured as a resistance temperature detector or a thermocouple instead of a thermistor.

[0047] The interior temperature sensor 42 detects the temperature of the interior space SP1 (an example of the state of the interior space SP1: hereinafter referred to as "interior temperature"). The interior temperature sensor 42 may be disposed, for example, inside the interior space SP1 (inside the vehicle cabin). The interior temperature sensor 42 may be configured with a thermistor whose resistance value changes depending on the interior temperature. The interior temperature sensor 42 may be configured with a resistance temperature detector or a thermocouple instead of a thermistor.

[0048] As shown in Fig. 4, the control device 26 is an electronic control unit (ECU) configured by a computer including a processor 26A such as a CPU (Central Processing Unit) or an MPU (Microprocessor Unit), a memory 26B such as a ROM (Read Only Memory) or a RAM (Random Access Memory), and a storage device 26C such as an SSD (Solid State Drive) or an HDD (Hard Disk Drive). The control device 26 can execute various processes by having the processor 26A read necessary data and application software from the memory 26B or the storage device 26C and execute predetermined arithmetic processing in accordance with the software. The control device 26 may be configured as a single piece of hardware, or may be configured as a unit consisting of multiple pieces of hardware.

[0049] 3, the control device 26 is connected to each component of the vehicle 1 via a communication network 43 such as a CAN (Controller Area Network), and controls each component of the vehicle 1. The communication network 43 may be configured with multiple networks, and may include, for example, a B-CAN and an F-CAN, which has a faster communication speed than the B-CAN.

[0050] The vehicle 1 is equipped with a battery 46. The battery 46 may be charged by regeneration using an electric motor, or may be charged by electric power from an ACG (alternator) provided in a gasoline engine.

[0051] The battery 46 functions as a voltage source that supplies power to various devices installed on the vehicle 1, including the propulsion device 14, the braking device 15, the HMI 17, the navigation device 18, the heating device 21, the external sensor 23, the vehicle sensor 24, and the control device 26.

[0052] The control device 26 includes, as functional units, an external environment recognition unit 52, a driving control unit 53, an anti-fogging control unit 54, and a memory unit 57. At least a portion of the functional units of the control device 26 may be realized by hardware such as an LSI, an ASIC, or an FPGA, or may be realized by a combination of software and hardware.

[0053] The external environment recognition unit 52 of the control device 26 recognizes the positions of targets (obstacles on the road on which the vehicle 1 is traveling, lane markings, vehicles ahead, etc.) present in the vehicle exterior space SP2 based on the detection results of the external environment sensor 23. For example, the external environment recognition unit 52 recognizes the positions of targets present ahead of the vehicle 1 by analyzing changes in density values ​​on the image captured by the front camera 10.

[0054] The driving control unit 53 of the control device 26 performs driving control of the vehicle 1 based on the positions of targets (obstacles on the roadway of the vehicle 1, lane markings, vehicles ahead, etc.) recognized by the external environment recognition unit 52. The driving control performed by the driving control unit 53 includes various driving controls (driving control equivalent to SAE autonomous driving levels 1 to 2) for configuring an Advanced Driver Assistance System (ADAS). In other embodiments, the driving control performed by the driving control unit 53 may include various driving controls (driving control equivalent to SAE autonomous driving levels 3 or higher) for achieving autonomous driving (AD).

[0055] Various types of driving controls that realize ADAS include, for example, lane keeping control and vehicle-in-front following control. In lane keeping control, the driving control unit 53 controls the steering device 16 so that the vehicle 1 travels at a reference position (for example, the center of the lane in the width direction) within a lane defined by dividing lines. In vehicle-in-front following control, the driving control unit 53 controls the propulsion device 14 and the braking device 15 so that the distance between the vehicle 1 and the vehicle in front is maintained within a predetermined range.

[0056] The defogging control unit 54 of the control device 26 controls the output of the heater 31 of the heating device 21 based on the detection result of the vehicle sensor 24 in order to suppress fogging of the windshield 6.

[0057] The defogging control unit 54 includes a heater control unit 55 and a heater control determination unit 56 .

[0058] The heater control unit 55 applies a voltage to the heater 31 to execute various processes for controlling the amount of heat output from the heater 31 .

[0059] The heater control unit 55 is configured to be able to perform a de-icing process in which a predetermined voltage (hereinafter referred to as supply voltage) is applied to the heater 31 and maintained thereon, an anti-fogging process in which a voltage pulse is applied to the heater 31 by PWM (Pulse Width Modulation) control, and a stop process in which no voltage is applied to the heater 31 and maintained thereon.

[0060] In PWM control, the defogging control unit 54 repeatedly switches on and off to generate a voltage pulse that repeatedly switches on and off, and applies the generated voltage pulse to the heater 31. At this time, the defogging control unit 54 generates a voltage pulse with a constant period that becomes the supply voltage when on (High) and becomes 0 V when off. In PWM control, the defogging control unit 54 controls the output from the heater 31 (more specifically, the amount of heat generated per unit time by the heater 31) by changing the ratio of the time that the voltage pulse remains on per period, i.e., the duty ratio.

[0061] The heater control unit 55 determines whether or not a predetermined condition is met based on the detection result of the vehicle sensor 24, and when it determines that the predetermined condition is met, it instructs the heater control unit 55 to execute the corresponding process.

[0062] The heater control determination unit 56 determines whether or not the conditions for performing the thawing process (hereinafter referred to as the thawing conditions) are met based on the detection results of the vehicle exterior temperature sensor 40 and the camera interior temperature sensor 41. When the thawing conditions are met, the heater control unit 55 instructs the heater control unit 55 to perform the thawing process.

[0063] The heater control determination unit 56 determines whether or not the conditions for performing the defogging process (hereinafter referred to as the defogging conditions) are met based on the detection results of the vehicle exterior temperature sensor 40 and the camera internal temperature sensor 41. When the defogging conditions are met, the heater control unit 55 instructs the heater control unit 55 to perform the defogging process.

[0064] The heater control determination unit 56 determines whether or not a condition for performing the stop process (hereinafter, the stop condition) is met based on the detection results of the vehicle exterior temperature sensor 40 and the camera internal temperature sensor 41. When the stop condition is met, the heater control unit 55 instructs the heater control unit 55 to perform the stop process.

[0065] The storage unit 57 of the control device 26 is configured with the memory 26B and / or the storage device 26C. The storage unit 57 stores various information required for controlling the vehicle 1 and for controlling the heater 31 performed by the defogging control unit 54.

[0066] The information stored in the memory unit 57 includes, for example, dynamic map data. The dynamic map data includes static information, quasi-static information, quasi-dynamic information, and dynamic information. The static information includes three-dimensional map information with higher accuracy than the map information stored in the navigation device 18. The quasi-static information includes traffic regulation information, road construction information, and wide-area weather information. The quasi-dynamic information includes accident information, congestion information, and narrow-area weather information. The dynamic information includes traffic signal information, nearby vehicle information, and pedestrian information. The control device 26 may connect to the high-accuracy map server 30B via the network N as appropriate and update the dynamic map data stored in the memory device 26C.

[0067] The information stored in the storage unit 57 includes various types of information required for the defogging control unit 54 to control the heater 31 (hereinafter referred to as heater control information).

[0068] The heater control information includes determination information indicating the relationship between the outside air temperature and the camera internal temperature and whether or not to perform the defrosting process. That is, the determination information indicates whether or not the outside air temperature and the camera internal temperature satisfy the conditions for performing the defrosting process (hereinafter referred to as the defrosting conditions).

[0069] In this embodiment, the determination information is represented by a true / false table shown in Fig. 5. In Fig. 4, True means that the thawing process is to be performed (the thawing conditions are met), and False means that the thawing process is not to be performed (the thawing conditions are not met). The boundary between the True region and the False region corresponds to a threshold value Th that distinguishes between whether or not the thawing process is to be performed.

[0070] As shown in FIG. 4, the threshold value Th is set to be maintained or to increase as the outside temperature decreases.

[0071] However, instead of a truth table, the memory unit 57 may store, as the determination information, a predetermined map or formula or the like that indicates the relationship between the outside vehicle temperature and the internal camera temperature and whether or not the de-icing process is performed.

[0072] <Output control processing> After the vehicle 1 starts, until the vehicle 1 stops, the defogging control unit 54 of the control device 26 executes an output control process at predetermined time intervals (for example, every minute). In the output control process, the defogging control unit 54 sets a voltage to be supplied to the heater 31, applies the voltage, and causes the heater 31 to generate heat (i.e., output heat from the heater 31). The output control process will be described in detail below with reference to FIG. 6. However, although the following description will be given assuming that the defogging control unit 54, which is a functional unit, executes various processes, this means that the processor 26A of the control device 26 executes predetermined processes in accordance with software, thereby executing various processes as the defogging control unit 54.

[0073] In the first step ST1 of the output control process, the defogging control unit 54 acquires the outside-vehicle temperature from the outside-vehicle temperature sensor 40 and the inside-camera temperature from the inside-camera temperature sensor 41. Once the acquisition is complete, the defogging control unit 54 refers to the determination information (true / false table) and determines whether the thawing conditions are met based on the outside-vehicle temperature and the inside-camera temperature.

[0074] In this embodiment, the anti-fogging control unit 54 acquires a corresponding threshold value Th (for example, when the outside temperature is -5°C, the threshold value Th is 20°C) based on the acquired outside temperature, and determines that the de-icing condition is met when the internal temperature of the camera is lower than the threshold value Th.

[0075] Alternatively, the anti-fogging control unit 54 may refer to the corresponding column in the truth table (for example, when the temperature outside the vehicle is -5°C and the temperature inside the camera is 5°C, the column in the first row and second column of the truth table) to determine whether the de-icing conditions are met.

[0076] The defogging control unit 54 executes step ST2 when the temperature outside the vehicle and the temperature inside the camera satisfy the defrosting conditions, and executes step ST3 when they do not satisfy the conditions.

[0077] In step ST2, the defogging control unit 54 executes the de-icing process. During the de-icing process, the defogging control unit 54 maintains the supply voltage applied to the heater 31. Once the de-icing process is started and the supply voltage is applied to the heater 31, the defogging control unit 54 ends the output control process while the supply voltage is still applied to the heater 31 (i.e., while the de-icing process is continuing).

[0078] In step ST3, the defogging control unit 54 determines whether the defogging condition is met (i.e., whether the defogging process should be performed). The defogging condition may be, for example, that the outside temperature is higher than -40°C and lower than 10°C. However, the defogging condition is not limited to this.

[0079] The defogging control unit 54 executes step ST4 if the defogging conditions are met, and executes step ST5 if the defogging conditions are not met.

[0080] In step ST4, the defogging control unit 54 executes the defogging process. In the defogging process, the defogging control unit 54 sets a duty ratio and applies a voltage pulse corresponding to the duty ratio to the heater 31. However, the defogging control unit 54 is configured to continue applying the voltage pulse corresponding to the duty ratio to the heater 31 until any one of the thawing process, the defogging process, and the stop process is started.

[0081] The defogging control unit 54 sets the duty ratio to a value greater than 0 and less than 1 (less than 1) in the defogging process.

[0082] The defogging control unit 54 may set the duty ratio to decrease as the camera internal temperature increases from the threshold value Th. For example, when the difference between the camera internal temperature and the threshold value Th is ΔT, the defogging control unit 54 may determine the duty ratio to be exp(-ΔT / T0) (where T0 is an arbitrary constant).

[0083] The defogging control unit 54 starts the defogging process by applying a voltage pulse corresponding to the duty ratio to the heater 31, and then ends the output control process while continuing the defogging process.

[0084] In step ST5, the defogging control unit 54 determines that the stop condition is satisfied and executes the stop process. In the stop process, the defogging control unit 54 stops the supply of voltage to the heater 31. When the defogging control unit 54 starts the stop process, the defogging control unit 54 ends the output control process while continuing the stop process (i.e., stopping the supply of voltage to the heater 31).

[0085] When the vehicle 1 is stopped, the defogging control unit 54 stops various processes such as the de-icing process, the defogging condition, and the stop process, and stops supplying voltage to the heater 31.

[0086] <Effects> Next, the effects of the defogging system X configured as described above will be described. The defogging control unit 54 determines whether the defrosting conditions are met (ST1) based on the vehicle exterior temperature detected by the vehicle exterior temperature sensor 40 and the camera internal temperature detected by the camera internal temperature sensor 41. If the defrosting conditions are met, the defogging control unit 54 executes the defrosting process, and if the defrosting conditions are not met, the defogging control unit 54 executes the defogging process or the stop process.

[0087] In the defrosting process, the defogging control unit 54 maintains the supply voltage applied to the heater 31. On the other hand, in the anti-fogging process, the defogging control unit 54 sets the duty ratio to less than 1, and in the stop process, the defogging control unit 54 stops the heater 31. In other words, the defogging control unit 54 sets the duty ratio to 1 in the defrosting process, to a value greater than 0 and less than 1 in the anti-fogging process, and to 0 in the stop process. Therefore, when the defrosting conditions are not met, the defogging control unit 54 suppresses the output of the heater 31 compared to when the defrosting conditions are met.

[0088] This limits the output of the heater 31 (the amount of heat emitted from the heater 31) when the ice-melting conditions are not met. This makes it possible to prevent the windshield 6 (more specifically, the panel that constitutes the windshield 6) from being suddenly heated. This makes it possible to reduce stress that may be applied to the windshield 6.

[0089] When the temperature outside the vehicle is low and the temperature inside the camera is also low, it is predicted that the windshield 6 will freeze. In particular, when the temperature outside the vehicle is low, it is necessary to continue outputting from the heater 31.

[0090] Therefore, in this embodiment, the threshold value Th is set to be higher as the outside temperature decreases. As a result, when the outside temperature is low, output from the heater 31 continues until the camera internal temperature exceeds the threshold value Th. Therefore, the threshold value Th can be set appropriately so that ice on the outer surface of the windshield 6 can be melted when the outside temperature is low.

[0091] In this way, by suppressing fogging of the front windshield 6, it is possible to reduce situations in which driving control of the vehicle 1 cannot be performed based on the image capture results of the front camera 10. Therefore, the present invention further improves traffic safety and contributes to the development of sustainable transportation systems.

[0092] <<Second embodiment>> The anti-fogging system X according to the second embodiment differs from the first embodiment in the conditions for performing the de-icing process, i.e., the de-icing conditions, but the other configurations are the same as those of the first embodiment. Therefore, a description of the other configurations will be omitted, and the de-icing conditions according to the second embodiment will be described below.

[0093] The thawing conditions in the second embodiment are determined based on the outside-vehicle temperature detected by the outside-vehicle temperature sensor 40 and the inside-vehicle temperature acquired by the inside-vehicle temperature sensor 42. In other words, in the second embodiment, the determination information indicates whether the outside-vehicle temperature and the inside-vehicle temperature satisfy the conditions for executing the thawing process.

[0094] Specifically, the determination information according to the second embodiment is shown by a true / false table shown in Fig. 7. In Fig. 7, True means that the thawing process is to be performed (the thawing conditions are met), and False means that the thawing process is not to be performed (the thawing conditions are not met). The boundary between the True region and the False region corresponds to a threshold value Th that distinguishes whether or not the thawing process is to be performed.

[0095] As shown in FIG. 7, the threshold value Th is set to be maintained or to decrease as the outside temperature decreases.

[0096] In the second embodiment, in the first step ST1 of the output control process, the defogging control unit 54 acquires the outside-vehicle temperature from the outside-vehicle temperature sensor 40 and the inside-vehicle temperature from the inside-vehicle temperature sensor 42. Once the acquisition is complete, the defogging control unit 54 refers to the determination information (true / false table) and determines whether the thawing conditions are met based on the outside and inside-vehicle temperatures.

[0097] The anti-fogging control unit 54, for example, acquires a corresponding threshold value Th (for example, when the outside temperature is -5°C, the threshold value Th is 10°C) based on the acquired outside temperature, and determines that the de-icing condition is met when the inside temperature is lower than the threshold value Th.

[0098] As in the first embodiment, the defogging control unit 54 executes step ST2 when it determines that the thawing condition is met, and executes step ST3 when it determines that the thawing condition is not met.

[0099] <Effects> Next, the effects of the defogging system X configured in this manner will be described. As in the first embodiment, when the defrosting conditions are not met, the output of the heater 31 (the amount of heat emitted from the heater 31) is limited. This makes it possible to prevent the windshield 6 (more specifically, the panel that constitutes the windshield 6) from being suddenly heated.

[0100] When the temperature outside the vehicle is low and the temperature inside the vehicle is also low, it is predicted that ice will adhere to the windshield 6. Therefore, by increasing the output of the heater 31, the ice can be properly melted.

[0101] When the air conditioner 20 is operating, the temperature difference between the temperature outside the vehicle and the temperature inside the vehicle is small, and it is predicted that the temperature difference between the temperature outside the vehicle and the temperature inside the vehicle will increase as the operating time of the air conditioner 20 becomes longer. On the other hand, as the operating time of the air conditioner 20 becomes longer, it is predicted that the front window 6 will be warmed as the temperature inside the vehicle rises, and ice adhering to the front window 6 will melt.

[0102] Therefore, in this embodiment, the true / false table is configured so that the supply voltage is applied to the heater 31 (i.e., the duty ratio is set to 1) until a sufficient temperature difference is obtained between the temperature outside the vehicle and the temperature inside the vehicle. As shown in Fig. 7, the threshold value Th is configured to decrease as the temperature outside the vehicle decreases. This allows the threshold value Th to be appropriately set based on the operating time of the air conditioner 20.

[0103] Although the description of the specific embodiment has been completed above, the present invention is not limited to the above embodiment and its modifications, and can be modified in a wide range of ways.

[0104] In the above embodiment, an example has been described in which the driving control unit 53 of the vehicle 1 performs driving control related to ADAS and AD, but it is not essential for the present invention that the driving control unit 53 perform driving control. The defogging system X may have any configuration as long as it includes a control device 26 provided with a defogging control unit 54, and the control device 26 controls the output of the heater 31 to prevent fogging of windows such as the windshield 6 and prevent the generation of stress inside the windshield 6. For example, the defogging control unit 54 may be configured by a computer (control device) different from the computer that performs driving control, etc. The control device 26 that configures the defogging control unit 54 may be housed inside the front camera 10.

[0105] In the above embodiment, the anti-fogging system X is described as preventing fogging of a portion of the windshield 6 located in front of the front camera 10, but the present invention is not limited to this. The present invention can be applied to an anti-fogging system X that prevents fogging of a portion of the window located within the field of view of an imaging device that captures an image of an exterior space SP2 from an interior space SP1 of the vehicle.

[0106] In the above embodiment, as shown in Figures 5 and 6, the determination information showing the relationship between the outside vehicle air temperature and the internal camera temperature (or the outside vehicle temperature and the internal vehicle temperature) and whether or not to perform the de-icing process is represented by a true / false table, but this is not limited to this. The determination information may also be represented by a map, a graph, or the like. For example, as shown in Figure 8, the determination information may be represented by a map with the outside vehicle air temperature on the horizontal axis and the internal camera temperature (internal vehicle temperature) on the vertical axis.

[0107] In the above embodiment, the control device 26 was configured to change the output of the heater 31 by changing the duty ratio, but the control device 26 may also be configured to change the output of the heater 31 by changing the voltage applied to the heater 31.

[0108] In the above embodiment, the control device 26 is configured to determine in ST1 whether the defrosting conditions are met, i.e., whether defrosting control should be performed, based on the vehicle exterior temperature and the camera interior temperature, or the vehicle exterior temperature and the vehicle interior temperature (see FIGS. 6 and 8). However, the present invention is not limited to this. For example, the control device 26 may obtain information via the weather server 30A and determine whether defrosting is required (whether the defrosting conditions are met).

[0109] A condensation sensor 60 (see Figure 2) is provided on the inside of the front windshield 6, and the control device 26 may be configured to determine whether de-icing control should be performed based on the detection results of the condensation sensor 60, the outside temperature detected by the outside temperature sensor 40, and the image taken by the front camera 10.

[0110] Specifically, the control device 26 first determines whether the outside-vehicle temperature acquired by the outside-vehicle temperature sensor 40 is equal to or lower than a predetermined threshold (a temperature threshold at which freezing or condensation may occur). The control device 26 executes a stop process when the outside-vehicle temperature is equal to or higher than the threshold. When the outside-vehicle temperature is lower than the threshold, the control device 26 acquires an image acquired by the front camera 10. The control device 26 then performs image color analysis of the image acquired by the front camera 10 to determine whether the field of view R of the windshield 6 is whitened. Next, when the field of view R is whitened and condensation is detected by the condensation sensor 60, the control device 26 determines that the field of view R is fogged and performs defogging control. When the field of view R is whitened and condensation is not detected by the condensation sensor 60, the control device 26 determines that the windshield 6 is frozen and performs a defrosting process. The control device 26 grays out the image acquired by the front camera 10, acquires a shading distribution, and determines whether the field of view R is whitened based on the shading distribution.

[0111] Alternatively, a capacitance sensor 62 (see FIG. 2) may be provided on the windshield 6 to detect ice on the windshield 6. The control device 26 may determine whether or not ice is present on the windshield 6 based on the capacitance detected by the capacitance sensor 62. The capacitance sensor 62 may include, for example, two electrodes (e.g., comb-shaped electrodes) provided on the windshield 6 and an electronic circuit for detecting the impedance (capacitance) between the two electrodes. The control device 26 may determine whether or not ice is present on the exterior of the windshield 6 based on the impedance detected by the capacitance sensor 62. The two electrodes of the capacitance sensor 62 are preferably disposed between the glass and the black ceramic 6A. In this manner, by disposing the electrodes constituting the capacitance sensor 62 between the glass and the black ceramic 6A, it is possible to reduce the effect of condensation on the interior side of the windshield 6 on the detection results of the capacitance sensor 62. [Explanation of symbols]

[0112] 1: Vehicle 3: Vehicle interior 6: Front window (an example of a window component) 10: Front camera (example of camera) 26: Control device 31: Heater 40: Outside temperature sensor 41: Camera internal temperature sensor 42: Vehicle interior temperature sensor R:Visual field X: Anti-fog system

Claims

1. An anti-fogging system for a camera that captures an image of the outside of a vehicle through a predetermined field of view set on a vehicle window, comprising: a heater for heating the viewing area; an outside temperature sensor that detects the temperature outside the vehicle compartment as the outside temperature; a dew condensation sensor provided on the interior side of the window; a control device that controls the heater based on the outside temperature acquired by the outside temperature sensor, the detection result by the condensation sensor, and the image captured by the camera, The control device When the outside temperature detected by the outside temperature sensor is less than a temperature threshold value, determining whether the field of view is whitened based on the captured image acquired from the camera; When the field of view is whitened and condensation is detected by the condensation sensor, an anti-fogging process is performed; When the field of view is white and no condensation is detected by the condensation sensor, the defrosting system performs a defrosting process by setting the heater output higher than that of the anti-fogging process.

2. An anti-fogging system for a camera that captures an image of the outside of a vehicle through a predetermined field of view set on a vehicle window, comprising: a heater for heating the viewing area; an outside temperature sensor that detects the temperature outside the vehicle compartment as the outside temperature; a capacitance sensor having two electrodes and a detection unit that detects capacitance between the two electrodes; a control device that controls the heater based on a detection result of the capacitance sensor, The control device determines whether a predetermined thawing condition is satisfied based on the capacitance detected by the detection unit, and when the thawing condition is not satisfied, reduces the output of the heater compared to when the thawing condition is satisfied, The window includes a panel made of glass and black ceramic printed on the interior surface of the panel so as to surround the viewing area, The two electrodes are respectively provided between the panel and the black ceramic.

3. the control device is capable of applying a voltage pulse that repeatedly turns on and off to the heater; 3. The anti-fogging system according to claim 1, wherein the output of the heater is changed by changing the duty ratio of the voltage pulse.

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