WO2024069676A1

WO2024069676A1 - Headlight control device and headlight control method

Info

Publication number: WO2024069676A1
Application number: PCT/JP2022/035616
Authority: WO
Inventors: 裕小野寺; 僚太郎江原; 悟井上
Original assignee: 三菱電機株式会社
Priority date: 2022-09-26
Filing date: 2022-09-26
Publication date: 2024-04-04

Abstract

The purpose of the present invention is to provide a technology that makes it possible to suppress the occurrence of glare for a driver of a vehicle while illuminating a region. This headlight control device comprises an acquisition unit and a control unit. When an object is present in a region illuminated by a headlight of a vehicle, the acquisition unit acquires, from a camera, object information pertaining to the object. While using the headlight to gradually increase the brightness in the region, the control unit uses the headlight to illuminate the object with a brightness corresponding to a type of the object, on the basis of the object information acquired by the acquisition unit.

Description

Headlamp control device and headlamp control method

This disclosure relates to a headlamp control device and a headlamp control method.

Auto light and auto high beam have been proposed as technologies that automatically turn on and off a vehicle's headlights based on the illuminance around the vehicle at night or when the vehicle enters a tunnel or overpass (for example, Patent Document 1).

Also, to reduce glare for pedestrians and others, a technology has been proposed for partially dimming or blocking the headlight illumination, such as adaptive driving beam (ADB) (for example, Patent Document 2).

JP 2021-195042 A Patent No. 5438410

However, with conventional technology, the headlights turn on and their brightness rises sharply when the headlights start to turn on due to a decrease in illuminance around the vehicle, or when dimming or blocking is released in the ADB. This causes problems such as glare for pedestrians and glare for the driver due to return reflection from objects such as signs that contain reflective material.

The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide technology that can reduce glare caused to the vehicle driver while brightening an area.

The headlight control device according to the present disclosure includes an acquisition unit that acquires object information about the object from a camera when an object is present in an area illuminated by the vehicle's headlights, and a control unit that illuminates the object with the headlights at a brightness corresponding to the type of object based on the object information while gradually increasing the brightness of the area with the headlights.

According to the present disclosure, while the brightness of the area is gradually increased by the headlights, the object is illuminated by the headlights at a brightness that corresponds to the type of object based on the object information. With this configuration, it is possible to prevent glare from being caused to the driver of the vehicle while the area is being brightened.

The objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings.

1 is a functional block diagram showing a main part of a headlamp control device according to a first embodiment. 3 is a diagram for explaining an example of control of the headlamp control device according to the first embodiment; FIG. 3 is a diagram for explaining an example of control of the headlamp control device according to the first embodiment; FIG. 3 is a diagram for explaining an example of control of the headlamp control device according to the first embodiment; FIG. 3 is a diagram for explaining an example of control of the headlamp control device according to the first embodiment; FIG. 4 is a flowchart showing an example of an operation of the headlamp control device according to the first embodiment. 10 is a flowchart showing an example of an operation of a headlamp control device according to a second embodiment. FIG. 11 is a functional block diagram showing a main part of a headlamp control device according to a third embodiment. FIG. 13 is a diagram for explaining an example of a determination made by a headlamp control device according to a third embodiment. FIG. 13 is a diagram for explaining an example of a determination made by a headlamp control device according to a third embodiment. FIG. 13 is a diagram for explaining an example of a determination made by a headlamp control device according to a third embodiment. 13 is a flowchart showing an example of an operation of a headlamp control device according to a third embodiment. FIG. 13 is a functional block diagram showing a main part of a headlamp control device according to a fourth embodiment. FIG. 13 is a top view for explaining an example of control of the headlamp control device according to the fourth embodiment. 13 is a flowchart showing an example of the operation of the headlamp control device according to the fourth embodiment. FIG. 13 is a top view for explaining an example of control of the headlamp control device according to the fifth embodiment. FIG. 13 is a block diagram showing a hardware configuration of a headlamp control device according to another modified example. FIG. 13 is a block diagram showing a hardware configuration of a headlamp control device according to another modified example.

<First embodiment>
1 is a functional block diagram showing a main part of a headlamp control device 1 according to the first embodiment. The headlamp control device 1 according to the first embodiment is mounted on a vehicle such as an automobile. In the following description, the vehicle on which the headlamp control device 1 is mounted may be referred to as a "vehicle," and a vehicle other than the vehicle on which the headlamp control device 1 is mounted may be referred to as an "other vehicle."

As shown in FIG. 1, the headlamp control device 1 is connected to an illuminance detection unit 2, an imaging unit 3, and a headlamp 4 so as to be able to communicate with them.

The headlamp 4 has a lamp with functions such as low beam, high beam, or spot beam, and has an ADB function that allows the headlamp 4's illumination range and illumination amount to be adjusted. The headlamp 4 configured in this way is capable of emitting light in various light distribution patterns based on the light distribution control signal from the headlamp control device 1.

The imaging unit 3 is, for example, a forward monitoring camera that captures a visible light image in front of the vehicle. The image is, for example, a moving image. The imaging unit 3 captures an image in front of the vehicle, generates object information based on the image, and outputs it to the headlight control device 1. The object information is information about objects that exist in the area illuminated by the headlights 4 (hereinafter sometimes referred to as the "illumination area").

In the present embodiment 1, the object information is information that allows the headlamp control device 1 to determine the type and position information of the object, and as an example, it will be described as an image signal showing an image in front of the vehicle. However, as will be described later, the object information is not limited to image signals, etc.

The illuminance detection unit 2 is, for example, an illuminance sensor. The illuminance detection unit 2 outputs the illuminance around the vehicle to the headlamp control device 1 as an illuminance signal. In the first embodiment, the illuminance detection unit 2 outputs the illuminance around the vehicle as an illuminance signal. Note that the illuminance signal is not limited to this, and for example, the illuminance detection unit 2 may output the luminance of an image captured by a camera possessed by the vehicle as an illuminance signal. In this case, the function of the imaging unit 3 can be realized by the illuminance detection unit 2.

Although not shown, the headlamp control device 1 is connected to a computer network within the vehicle (e.g., CAN (Controller Area Network)) and can appropriately acquire various information (hereinafter referred to as "vehicle information") from the vehicle. The vehicle information includes, for example, information indicating whether the light switch is on or off. The light switch is configured to be able to switch between the on and off states of the headlamp 4, and to switch whether or not to automatically control the headlamp 4. For example, when an operation to execute automatic control of the headlamp 4 is performed on the light switch, automatic control of the headlamp 4 is executed by the headlamp control device 1.

Next, the headlight control device 1 will be described. The headlight control device 1 acquires an illuminance signal relating to the illuminance around the vehicle from the illuminance detection unit 2, acquires object information from the imaging unit 3, and outputs a light distribution control signal for controlling the headlight 4 to the headlight 4 based on the illuminance signal and the object information. This enables the headlight control device 1 to automatically control the light distribution of the vehicle's headlight 4. The headlight control device 1 in Figure 1 includes a lighting determination unit 11, an acquisition unit 12, and a control unit 13.

The light-on determination unit 11 selectively determines whether the headlights 4 are on or off based on the illuminance signal from the illuminance detection unit 2. The light-on determination unit 11 outputs a light-on signal to the control unit 13 when the illuminance indicated by the illuminance signal is equal to or lower than a threshold value, and outputs an off signal to the control unit 13 when the illuminance is greater than the threshold value.

The acquisition unit 12 acquires object information (image capture signals in this embodiment 1) from the image capture unit 3, which is a camera.

The control unit 13 starts lighting control of the headlights 4 when a lighting signal indicating illuminance exceeding a threshold value is output from the lighting determination unit 11. When lighting control starts, the control unit 13 gradually increases the brightness of the area illuminated by the headlights 4, i.e., the brightness of the illumination area. Note that in this embodiment 1, the control unit 13 controls the brightness of the headlights 4 with the luminance of the headlights 4, so the brightness described in this embodiment 1 is substantially the same as the luminance. The control unit 13 linearly increases the brightness of the illumination area by having the headlights 4 illuminate the illumination area in order of luminance from among a plurality of predetermined luminances, starting with the darkest luminance.

In parallel with the above processing, the control unit 13 determines the type and position of an object present in the illumination area based on the object information (imaging signal in this embodiment 1) acquired by the acquisition unit 12. The determination of the type and position of an object can be realized by known information processing techniques such as pattern recognition and machine learning. The types of objects are, for example, other vehicles, people (e.g., cyclists and pedestrians), signs (e.g., road signs), road structures, road marks, etc. In this embodiment 1, the control unit 13 determining the type and position of an object is essentially the same as the control unit 13 detecting an object.

The control unit 13 illuminates the position of the object determined above with the headlights 4 at a brightness corresponding to the type of object determined above. Although details will be described later, the control unit 13 illuminates the object as part of the illumination area until the brightness of the illumination area gradually increased by the headlights 4 reaches a brightness corresponding to the type of object. Then, when the brightness of the illumination area gradually increased by the headlights 4 exceeds the brightness corresponding to the type of object, the control unit 13 illuminates the object and the illumination area at different brightnesses.

The control unit 13 configured as described above generates a light distribution control signal for illuminating an object with the headlight 4 at a brightness corresponding to the type of object based on the object information while gradually increasing the brightness of the illumination area with the headlight 4. In this way, the control unit 13 controls the light distribution of the headlight 4.

FIGS. 2 to 5 are diagrams for explaining an example of control by the control unit 13 in this embodiment 1.

FIG. 2 is a diagram for explaining a series of controls in which the control unit 13 starts turning on the headlights 4 in response to a turn-on signal, and gradually increases the brightness of the headlights 4 while illuminating an object with the headlights 4 at a brightness corresponding to the type of object. The horizontal axis of FIG. 2 indicates time, and the vertical axis indicates the light distribution control signal, i.e., the brightness of the headlights 4.

In the example of Figure 2, a linear slope with a gradient ΔB is set for the change in brightness of the headlight 4, and the brightness of the headlight 4 increases linearly.

In the first embodiment, brightness corresponding to the type of object is set for signs and people. Specifically, brightness B2 is set as the brightness of the headlight 4 corresponding to signs, and brightness B3 is set as the brightness of the headlight 4 corresponding to people.

Similarly, in the example of FIG. 2, the brightness of the headlight 4 corresponding to the illumination area where an object is not ultimately detected is set to brightness B4, which has an upper limit equal to the standard brightness of the headlight 4. Note that the "gradually" in the description of gradually increasing the brightness of the illumination area by the headlight 4 corresponds to the fact that the time until the illumination area is illuminated at the brightness B4 corresponding to the illumination area is longer than the time until the object is illuminated at the brightness corresponding to the type of object.

As shown in FIG. 2, when the object type is a person, the brightness B3 corresponding to the object type is greater than the brightness B2 corresponding to the object type when the object type is a sign. The brightness B4 of the headlight 4 corresponding to the illumination area where an object is not ultimately detected is greater than the brightnesses B2 and B3 corresponding to the object types.

Here, brightness B4 is set to 100%. Brightness B2 is set to a brightness that allows the vehicle driver to recognize the sign, within a range that is greater than the brightness at which the control unit 13 can detect the sign (e.g., 50%) and has an upper limit of brightness that does not cause glare to the vehicle driver or the like due to reflected light from the illuminated sign (e.g., 60%).

Brightness B3 is set to a brightness that allows the driver of the vehicle to recognize people, within a range that is greater than the brightness at which the control unit 13 can detect people (e.g., 70%) and has an upper limit of brightness that does not cause glare on illuminated people, etc. (e.g., 80%).

In the first embodiment, when the control unit 13 detects another vehicle based on the object information, the control unit 13 does not illuminate the other vehicle with the headlights 4. Therefore, the brightness B1 of the headlights 4 corresponding to the other vehicle shown in FIG. 2 is substantially the same as the brightness (0%) of the headlights 4 when they are turned off.

Figures 3, 4 and 5 are diagrams showing an example of a traffic scene as seen by a driver of a vehicle at a certain time. Figures 3 to 5 show area A1 where there is another vehicle 31 traveling ahead of the vehicle, area A2 where there is a road sign 32, which is a sign, area A3 where there is a pedestrian 33, which is a person, and an area where no object is ultimately detected, for example area A4.

Below, the change in brightness of the headlight 4 will be explained over time. At time t-1, the control unit 13 turns off the headlight 4.

At time t, the lighting determination unit 11 outputs a lighting signal, and the control unit 13 starts controlling the lighting of the headlights 4. FIG. 3 is a diagram showing a traffic scene at time t. The control unit 13 detects an object based on the object information (image pickup signal in the present embodiment 1) acquired by the acquisition unit 12. At time t, the headlights 4 are not yet turned on, and the image shown by the image pickup signal is dark, so the control unit 13 cannot detect the road sign 32 and the pedestrian 33. On the other hand, the tail lamps 31a, etc. of the other vehicle 31 are turned on, so the control unit 13 can detect the other vehicle 31 from the dark image. The control unit 13 is configured not to illuminate the other vehicle 31 and the area A1 with the headlights 4 when it is determined that the type of the object is the other vehicle 31 based on the object information. With this configuration, it is possible to suppress glare for the driver of the other vehicle 31.

From time t to time t+1, the control unit 13 gradually brightens the illumination area other than area A1 using the headlights 4. FIG. 4 is a diagram showing a traffic scene at time t+1. In FIG. 4, the illumination area other than area A1 is brighter than the illumination area in FIG. 3. By gradually increasing the brightness of the illumination area, it is possible to prevent a perceptual gap caused by a sudden change in the brightness of the light, and therefore to reduce discomfort to the driver of the vehicle. In addition, by gradually increasing the output in the headlights 4, it is possible to reduce the load on the Boost circuit, which is expected to simplify the voltage resistance of the Boost circuit.

Between time t and time t+1, the brightness of areas A2 to A4 gradually increases until the control unit 13 can detect the road sign 32. Generally, road signs 32 are coated with a retroreflective material, so the minimum brightness required for the control unit 13 to detect the road sign 32 is less than the minimum brightness required for the control unit 13 to detect the pedestrian 33. When the control unit 13 determines that the type of object is a road sign 32 based on the object information, it sets brightness B2 for area A2 where the road sign 32 is present. At time t+1, when the brightness of area A2 reaches brightness B2 along with the other illuminated areas, it is maintained at brightness B2 without becoming brighter than that.

Generally, signs coated with retroreflective material have the advantage that they are easily recognized by drivers with only a small amount of light, but the disadvantage that they are easily dazzling when illuminated. Despite this, in conventional technology, when the headlights 4 are turned on, the brightness of the headlights 4 is first increased relatively to detect the sign, and then the brightness is reduced. This causes a problem in that glare is experienced by the driver of the vehicle immediately after the headlights 4 are turned on.

In contrast to this, in the present embodiment 1, while the brightness of the illumination area is gradually increased by the headlights 4, that is, before the brightness of the illumination area reaches brightness B4, the sign is illuminated by the headlights 4 at brightness B2 corresponding to the sign. This makes it possible to suppress glare for the driver of the vehicle. Note that brightness B2 is set to a brightness that allows the driver of the vehicle to recognize the sign, within a range that is greater than the brightness at which the control unit 13 can detect the sign and has an upper limit value of brightness that does not cause glare to the driver of the vehicle, etc. This makes it possible to achieve both safety in object recognition and suppression of glare for the driver of the vehicle, and further reduces power consumption.

From time t+1 to time t+2, the control unit 13 uses the headlights 4 to gradually brighten the illumination areas other than areas A1 and A2. During this time, the brightness of areas A3 and A4 gradually increases until the control unit 13 can detect a pedestrian 33. If the control unit 13 determines that the type of object is a pedestrian 33 based on the object information, it sets brightness B3 for area A3 where the pedestrian 33 is present. At time t+2, when the brightness of area A3, along with the other illumination areas, reaches brightness B3, it is maintained at brightness B3 without becoming brighter than that.

In the prior art, when the headlights 4 start to be turned on, the brightness of the headlights 4 is increased relatively once to detect a person, and then the brightness is decreased. This causes a problem in that glare is caused on the person immediately after the headlights 4 are turned on. In contrast, in the present embodiment 1, while the brightness of the illumination area is gradually increased by the headlights 4, that is, before the brightness of the illumination area reaches brightness B4, the headlights 4 illuminate the person at brightness B3 corresponding to the person. This makes it possible to suppress glare on the person. Note that brightness B3 is set to a brightness that allows the vehicle driver to recognize the person, within a range that is greater than the brightness at which the control unit 13 can detect the person and has an upper limit value of brightness that does not cause glare on people, etc. This makes it possible to achieve both safety in object recognition and suppression of glare on people, and further to reduce power consumption.

From time t+2 to time t+3, the control unit 13 gradually brightens the illumination areas other than areas A1 to A3 using the headlights 4. Figure 5 shows a traffic scene at time t+3. Because no new object types are detected, the control unit 13 sets brightness B4 to illumination areas where no objects are detected, such as area A4. Area A4, where no traffic participants (e.g. the driver of the vehicle, the driver of another vehicle 31, and pedestrian 33) are present, is illuminated at brightness B4, improving the visibility of the vehicle driver at night.

As a result of the above, area A1 where other vehicles 31 exist is not illuminated, and area A2 where road signs 32 exist is illuminated with brightness B2 that is greater than brightness B1. Area A3 where pedestrians 33 exist is illuminated with brightness B3 that is greater than brightness B2, and area A4 where no object is detected is illuminated with brightness B4 that is greater than brightness B3.

<Operation>
6 is a flowchart showing an example of the operation of the headlamp control device 1 according to the embodiment 1. First, in step S1, the illuminance detection unit 2 detects an illuminance signal, and the lighting determination unit 11 acquires the illuminance signal.

In step S2, the lighting determination unit 11 determines whether the illuminance indicated by the illuminance signal is equal to or less than a threshold value. If it is determined that the illuminance is equal to or less than the threshold value, the process proceeds to step S3, and if it is determined that the illuminance is greater than the threshold value, the operation in FIG. 6 ends.

In step S3, the imaging unit 3 captures an image and generates an imaging signal as object information, and the acquisition unit 12 acquires the object information.

In step S4, the control unit 13 determines whether or not the type of object present in the illumination area has been determined based on the object information. If it is determined that the type of object has been determined, the process proceeds to step S5, and if it is determined that the type of object has not been determined, the process proceeds to step S6.

In step S5, the control unit 13 sets a brightness corresponding to the type of object for the area in which the object exists.

In step S6, the control unit 13 determines whether the headlights 4 are on or not. If it is determined that the headlights 4 are on, the process proceeds to step S8, and if it is determined that the headlights 4 are not on, the process proceeds to step S7.

In step S7, the control unit 13 turns on the headlights 4.

In step S8, it is determined whether the brightness of the illumination area has reached the brightness (e.g., brightness B4 in FIG. 2) set for the illumination area where an object is not ultimately detected. If it is determined that the brightness of the illumination area has reached the set brightness, the operation in FIG. 6 ends, and if it is determined that the brightness of the illumination area has not reached the set brightness, the process proceeds to step S9.

In step S9, the control unit 13 increases the brightness of the illumination area by ΔB. However, if the type of object is determined and the brightness of the illumination area exceeds the brightness corresponding to the type of object, the control unit 13 illuminates the object with the headlights 4 at the brightness corresponding to the type of object. After that, the process returns to step S3.

Summary of the First Embodiment
According to the headlight control device 1 of the first embodiment as described above, while the brightness of the illumination area is gradually increased by the headlights 4, the object is illuminated by the headlights 4 at a brightness corresponding to the type of the object based on the object information. With this configuration, while the illumination area is being brightened, glare to the driver of the vehicle can be suppressed, and the driver of the vehicle can easily identify the object. Furthermore, by gradually increasing the brightness of the illumination area by the headlights 4, the control unit 13 can easily determine the type of object, regardless of the brightness around the vehicle.

In addition, in this embodiment 1, the brightness of the illuminated area is increased linearly, which reduces discomfort to the vehicle driver.

In addition, in the first embodiment, the headlights 4 are caused to illuminate the illumination area at a predetermined brightness. This allows the headlights 4 to be controlled in an open loop, simplifying the control of the headlight control device 1.

In addition, in this embodiment 1, the brightness corresponding to a person is greater than the brightness corresponding to a sign, and if the type of object is determined to be another vehicle, the headlights 4 do not illuminate the other vehicle. With this configuration, it is possible to reduce glare for the driver of the vehicle, people, and drivers of other vehicles, and the driver of the vehicle can easily identify other vehicles, signs, and people.

<Modification>
In the first embodiment, the object information is an imaging signal that enables the headlight control device 1 to determine the type and position information of an object, but is not limited to this. For example, if the imaging unit 3 is capable of determining the type and position of an object based on an image in front of the vehicle, the object information may be the determination result of the type and position of the object in the imaging unit 3. In this case, the control unit 13 may use the object information from the imaging unit 3, i.e., the determination result of the type and position of the object by the imaging unit 3, as the determination result by the control unit 13. Furthermore, the imaging unit 3 and the control unit 13 may work together to determine the type and position of an object.

In addition, in the first embodiment, the lighting determination unit 11 selectively determines whether the headlights 4 are on or off based on the illuminance signal from the illuminance detection unit 2, but this is not limited to the above. For example, the lighting determination unit 11 may selectively determine whether the headlights 4 are on or off based on the on/off state of the light switch included in the vehicle information, that is, based on the operation of the light switch.

In addition, in the first embodiment, when the control unit 13 determines that the type of object is another vehicle, the control unit 13 does not illuminate the other vehicle with the headlights 4. However, the control unit 13 may illuminate the other vehicle with the headlights 4 to an extent that can be regarded as not substantially illuminating the other vehicle.

In addition, in the first embodiment, the object types were other vehicles, signs, and people, but are not limited to this. Furthermore, the brightness corresponding to signs and people is not limited to the brightness described in the first embodiment.

In addition, in the first embodiment, the brightness with which the headlights 4 illuminate an object is set based on the type of object, but it may be changed as appropriate depending on the distance and direction of the object, etc.

The brightness described in the first embodiment may be set to the minimum brightness that can be perceived by the driver of the vehicle, or may be set to the minimum brightness at which the control unit 13 can detect an object.

In addition, in the first embodiment, the gradient ΔB of the change in brightness of the illumination area is a fixed value, but it may be changed based on the type of object, distance, direction, and vehicle speed, etc.

In addition, in the first embodiment, the control unit 13 linearly increases the illumination area according to a linear slope having a gradient ΔB, but the illumination area may also be increased in a stepped manner, i.e., in stages. With this configuration, the illumination area can be brightened quickly, and the type of object can be detected quickly.

In the first embodiment, if an object is newly detected after the brightness of the illumination area exceeds the brightness corresponding to the type of object, the control unit 13 may reduce the brightness of the object in the illumination area to the brightness corresponding to the type of object. For example, if a pedestrian is newly detected in the area A4 in FIG. 5 that is illuminated at brightness B4 without any object being detected, the control unit 13 may illuminate the area A4 with the headlights 4 at the brightness B3 corresponding to a pedestrian. Conversely, if an object that was previously present is no longer present, the control unit 13 may illuminate the area where the object was present with the headlights 4 at the illumination area brightness B4. The above modified examples may be applied to embodiments other than the first embodiment.

<Embodiment 2>
In the first embodiment, the control unit 13 controls the brightness of the headlights 4 by luminance. That is, the brightness corresponding to an object is preset to a luminance that is assumed to enable the driver or the control unit 13 to recognize the object. However, unlike illuminance, luminance is not the brightness received by the observer. For this reason, depending on the environment and conditions, the brightness of an object may be too much or too little for the driver or the control unit 13.

For example, if a sign is not coated with a retroreflective material, the brightness corresponding to the sign described in embodiment 1 may be insufficient for the driver or control unit 13. Also, for example, if a pedestrian is wearing dark clothing with poor visibility, the brightness corresponding to the person described in embodiment 1 may be insufficient for the driver or control unit 13. Also, for example, if the headlights 4 are determined to be turned on, but the brightness around the vehicle is somewhat high due to street lights or the like, the brightness corresponding to the area where no object is detected may be excessive for the driver or control unit 13.

In response to this, the headlamp control device 1 according to the second embodiment described below is configured to control the brightness of the headlamp 4 using illuminance rather than luminance in order to solve this problem.

The functional block diagram of the headlamp control device 1 according to the second embodiment is the same as the functional block diagram of the headlamp control device 1 according to the first embodiment (see FIG. 1). Below, among the components according to the second embodiment, the components that are the same as or similar to the components described above are given the same or similar reference numerals, and different components are mainly described.

The acquisition unit 12 according to the second embodiment acquires the illuminance of an object illuminated by the headlight 4. For example, the acquisition unit 12 acquires the illuminance of an object illuminated by the headlight 4 from the luminance of an image captured by the imaging unit 3.

The control unit 13 performs feedback control of the headlights 4 based on the illuminance acquired by the acquisition unit 12 and a predetermined illuminance so that the acquired illuminance is substantially the same as the predetermined illuminance. In other words, if the illuminance of an object acquired by the acquisition unit 12 is lower than the predetermined illuminance, the control unit 13 increases the brightness of the object. On the other hand, if the illuminance of an object acquired by the acquisition unit 12 is higher than the predetermined illuminance, the control unit 13 decreases the brightness of the object.

<Operation>
Fig. 7 is a flowchart showing an example of the operation of the headlamp control device 1 according to the embodiment 2. The flowchart in Fig. 7 is similar to the flowchart in Fig. 6 except that step S11 is added between step S7 and step S8 and step S9 is changed to step S12. Therefore, steps S11 and S12 will be mainly described below.

In step S11, the imaging unit 3 captures an image, and the acquisition unit 12 acquires the illuminance of the object illuminated by the headlight 4 based on the image. Then, the process proceeds to step S8.

In step S12, the control unit 13 performs substantially the same control as in step S9 in FIG. 6. However, the control unit 13 performs feedback control based on the illuminance acquired in step S11. After that, the process returns to step S3.

Summary of the second embodiment
According to the headlamp control device 1 of the second embodiment described above, the headlamp 4 is feedback-controlled based on the acquired illuminance and the predetermined illuminance. With this configuration, it is possible to suppress the influence of the environment on the brightness of an object, and therefore it is possible to optimize the brightness of the object.

<Third embodiment>
8 is a functional block diagram showing a main part of the headlamp control device 1 according to the present embodiment 3. Hereinafter, among the components according to the present embodiment 3, the components that are the same as or similar to the components described above are given the same or similar reference numerals, and different components will be mainly described.

The configuration of FIG. 8 is the same as the configuration of FIG. 1, except that a danger determination unit 13a is added to the control unit 13. Note that the danger determination unit 13a may be provided outside the control unit 13 so as to be able to communicate with the control unit 13.

The risk determination unit 13a determines whether or not there is a predetermined possibility of a collision between the vehicle and an object. An example of the risk determination unit 13a is described below.

After the control unit 13 detects an object, if the position (i.e., coordinates) of the object in the image changes due to movement of at least one of the vehicle and the object, the danger determination unit 13a tracks the movement of the object. Tracking of the movement of an object can be achieved by known information processing technology, such as Multi-Object Tracking, which tracks the movements of multiple specific objects in a moving image.

The risk determination unit 13a determines whether or not there is a predetermined possibility of collision between the vehicle and the object based on the tracking of the object. Figures 9 to 11 are diagrams for explaining an example of collision possibility determination by the risk determination unit 13a. Figures 9 to 11 show a roadway 36, a vehicle 37 traveling on the roadway 36, and an object 38 with which the vehicle 37 may collide.

As shown in FIG. 9, when an object 38 detected in the initial detection stage is present in the traveling direction of the vehicle 37, the danger determination unit 13a predicts a collision between the two based on the traveling direction and speed of the vehicle 37 and the traveling direction and speed of the object 38. Then, when the danger determination unit 13a determines that the two will collide, it determines that there is a predetermined possibility of a collision.

As shown in FIG. 10, when an object 38 with limited brightness is moving toward a roadway 36, the risk determination unit 13a predicts a collision between the two based on the traveling direction and speed of the vehicle 37 and the traveling direction and speed of the object 38. Then, when the risk determination unit 13a determines that the two will collide, it determines that there is a possibility of a collision.

The risk determination unit 13a determines whether an object 38 with limited brightness exists within a predetermined distance from the area in the traveling direction of the roadway 36 or the vehicle 37 without predicting a collision as described in Figures 9 and 10. Then, when the risk determination unit 13a determines that the object 38 exists within a predetermined distance from the area in the traveling direction of the roadway 36 or the vehicle 37 as in Figure 11, it determines that there is a possibility of a collision. For example, if the object 38 is a pedestrian checking the traffic conditions before crossing the road, the object 38 exists within a predetermined distance from the area in the traveling direction of the roadway 36 or the vehicle 37, and therefore the risk determination unit 13a can determine that there is a possibility of a collision.

The control unit 13 in FIG. 8 increases the upper brightness limit corresponding to the type of object for which a collision is determined to be possible. For example, the danger determination unit 13a determines whether or not there is a predetermined collision possibility between the vehicle and the object after the area in which the object exists is illuminated with a brightness corresponding to the type of object. Then, when it is determined that there is a collision possibility, the control unit 13 increases the brightness of the object by increasing the upper brightness limit corresponding to the object.

The control unit 13 outputs a light distribution control signal to the headlights 4 so that the brightness corresponding to the type of object determined to be a potential collision target is increased in a stepped manner, i.e., stepwise, steeply up to an upper limit. This causes the brightness corresponding to the type of object to increase steeply, creating a perceptual gap for the vehicle driver, allowing the driver to focus their attention on the object. As long as this can be achieved, the presentation format of objects determined to be a potential collision target is not limited to this.

<Operation>
Fig. 12 is a flowchart showing the operation of the headlamp control device 1 according to the third embodiment. The flowchart in Fig. 12 is similar to the flowchart in Fig. 6, except that step S21 is added between step S4 and step S5, and steps S22 and S23 are added between step S5 and step S6. For this reason, steps S21 to S23 will be mainly described below.

In step S21, if the object is the same as the previously detected object, the danger determination unit 13a tracks the movement of the object. Then, the process proceeds to step S5.

In step S22, the risk determination unit 13a determines whether or not there is a predetermined possibility of a collision between the vehicle and the object based on the tracking result. If it is determined that there is a predetermined possibility of a collision, the process proceeds to step S23, and if it is determined that there is no predetermined possibility of a collision, the process proceeds to step S6.

In step S23, the control unit 13 increases the upper limit of brightness corresponding to the type of object for which it has been determined that there is a predetermined collision possibility. Then, the process proceeds to step S6.

<Summary of the Third Embodiment>
According to the headlamp control device 1 of the third embodiment described above, for an object determined to have a collision possibility, the upper limit value of brightness corresponding to the type of object is increased. With this configuration, the driver of the vehicle can easily recognize an object that has the possibility of interfering with the traveling of the vehicle.

<Modification>
In the third embodiment, the control unit 13 increases the upper limit value of the brightness corresponding to the type of object for which a collision possibility has occurred, but the upper limit value may be released. That is, the control unit 13 may set the upper limit value of the brightness of an object for which a collision possibility has occurred to be the same as the brightness of an illumination area in which the type of object is not detected. In this case, the control unit 13 may increase the brightness corresponding to the type of object for which a collision possibility has occurred in a stepped manner, i.e., stepwise and steeply.

<Fourth embodiment>
In the modified example of the first embodiment, when the brightness of the illumination area exceeds the brightness corresponding to the type of the object and the object is newly detected, the control unit 13 reduces the brightness of the object in the illumination area to the brightness corresponding to the type of the object. However, since it takes a certain amount of time from when the object enters the illumination area until the brightness is reduced to the brightness corresponding to the type of the object, there is a possibility that glare may occur to the driver of the vehicle during that time. In contrast, the headlamp control device 1 according to the fourth embodiment described below is configured to be able to solve such a problem.

FIG. 13 is a functional block diagram showing the main parts of the headlamp control device 1 according to the fourth embodiment. Below, among the components according to the fourth embodiment, components that are the same as or similar to the components described above are given the same or similar reference numerals, and different components are mainly described.

The configuration in FIG. 13 is the same as the configuration in FIG. 1 in which the control unit 13 is connected to the detection unit 5. The detection unit 5 detects objects that exist farther than the illumination area of the vehicle, that is, objects that exist farther than the detection range of the imaging unit 3 at night, without relying on the illumination of the headlights 4, and generates object detection information including the detection results. In this embodiment 4, the detection of an object by the detection unit 5 includes detection of the position of the object. The detection unit 5 is a distance measurement sensor mounted on the vehicle, such as a LiDAR (Light detection and Ranging), a ToF (Time of Flight) camera, an infrared camera, a millimeter wave radar, or an ultrasonic sensor.

The detection unit 5 is not limited to a distance measurement sensor mounted on the vehicle. For example, the detection unit 5 may be a communication device that acquires object detection information detected by a sensor possessed by another vehicle using V2V (Vehicle-to-Vehicle) technology. Or, for example, the detection unit 5 may be a communication device that acquires object detection information detected by infrastructure sensors such as roadside cameras and roadside LiDAR, location information from mobile phones, and external devices of the vehicle such as dynamic maps using V2X (Vehicle-to-Everything) technology.

The acquisition unit 12 acquires object detection information from the detection unit 5. Then, when the control unit 13 detects, based on the acquired object detection information, that an object exists farther away from the vehicle than the illumination area, the control unit 13 darkens the brightness of the portion of the illumination area into which the object will enter in the future by lowering the upper limit value of the brightness of the portion. For example, the portion into which the object will enter in the future may be the portion of the illumination area that is closest to the position of the object indicated in the object detection information. Or, for example, the portion into which the object will enter in the future may be the portion of the illumination area that is determined to be the portion into which the object will enter in the future based on the position and speed of the object indicated in the object detection information by a determination similar to that made by the danger determination unit 13a according to embodiment 3.

FIG. 14 is a top view for explaining an example of control by the control unit 13 according to the fourth embodiment. In FIG. 14, a vehicle 37, a road sign 32, a pedestrian 33, an illumination area 39 indicated by a thick line, and a detection area 40 are illustrated.

Generally, the illumination area 39 illuminated by the headlights 4 is different from the area in which the control unit 13 can detect objects based on object information, but for simplicity, they are considered to be the same here. The detection area 40 is the area in which the detection unit 5 can detect objects. It is assumed that the detection unit 5 is a millimeter wave radar, and the distance from the vehicle 37 to the edge of the detection area 40 is also greater than the distance from the vehicle 37 to the edge of the illumination area 39.

When the road sign 32 and pedestrian 33 approach the vehicle 37 due to the vehicle 37 traveling, as shown in FIG. 14, they are not present in the illumination area 39 but are present in the detection area 40. In this case, the detection unit 5 detects the road sign 32 and pedestrian 33 and outputs object detection information to the control unit 13. Based on the object information from the imaging unit 3 and the object detection information from the detection unit 5, the control unit 13 detects the road sign 32 and pedestrian 33 that are not present in the illumination area 39 but are present in the detection area 40. When such a detection result is obtained, the control unit 13 calculates the

portions

39a and 39b of the illumination area 39 into which the road sign 32 and pedestrian 33 will enter in the future, and makes the brightness of the

portions

39a and 39b darker than the brightness of the illumination area 39 other than the

portions

39a and 39b.

When the road sign 32 and pedestrian 33 come closer to the vehicle 37 due to the vehicle 37 traveling, they will be present in the illumination area 39, and the control unit 13 will detect the road sign 32 and pedestrian 33 present in the illumination area 39 based on the object information from the imaging unit 3. When such a detection result is obtained, the control unit 13 will illuminate the road sign 32 and pedestrian 33 with the headlights 4 at a brightness corresponding to the road sign 32 and pedestrian 33, as in the first embodiment.

<Operation>
Fig. 15 is a flowchart showing the operation of the headlamp control device 1 according to the fourth embodiment. The flowchart in Fig. 15 is similar to the flowchart in Fig. 6, except that steps S31 to S33 are added between steps S5 and S6. Therefore, steps S31 to S33 will be mainly described below.

In step S31, the detection unit 5 generates object detection information, and the acquisition unit 12 acquires the object detection information. In step S32, the control unit 13 determines whether the detected object will enter the illumination area in the future based on the object information and the object detection information. For example, if an object is present in an area of the detection area of the detection unit 5 that is outside the illumination area and within a predetermined distance from the illumination area, the control unit 13 determines that the object will enter the illumination area in the future. If it is determined that the detected object will enter the illumination area in the future, the process proceeds to step S33, and if it is determined that the detected object will not enter the illumination area in the future, the process proceeds to step S6.

In step S33, the control unit 13 lowers the upper brightness limit of the portion of the illumination area into which the object will enter in the future. The process then proceeds to step S6. According to the above operation, if an object is present in an area of the detection area of the detection unit 5 that is relatively close to the illumination area, the brightness of the illumination area relating to the object becomes darker, but if an object is present in an area relatively far from the illumination area, the brightness of the illumination area relating to the object is maintained.

Summary of the Fourth Embodiment
According to the headlight control device 1 of the fourth embodiment as described above, when it is detected that an object exists farther away than the illumination area of the vehicle, the brightness of the portion of the illumination area into which the object will enter in the future is dimmed. With this configuration, even if a new object enters the illumination area due to the movement of the vehicle after the headlights 4 are turned on, the glare caused by the entry of the new object can be suppressed.

<Modification>
In the fourth embodiment, the detection unit 5 may be a sensor capable of determining the type of an object to some extent, or a receiver capable of receiving the determination result of the type of the object, as described in the following fifth embodiment. In this case, the control unit 13 may change the brightness of a portion of the illumination area into which the object will enter in the future, based on the determination result.

<Fifth embodiment>
In the first embodiment, the imaging unit 3 was a camera such as a forward monitoring camera that captures visible light images, but images from such a camera are easily affected by the environment outside the vehicle (e.g., rain, snow, fog, etc.), which may reduce the reliability of the object type determination by the control unit 13. In contrast, the headlamp control device 1 according to the following fifth embodiment is configured to be able to solve such problems.

The functional block diagram of the headlamp control device 1 according to the fifth embodiment is the same as the functional block diagram of the headlamp control device 1 according to the fourth embodiment (see FIG. 13). Below, among the components according to the fifth embodiment, the components that are the same as or similar to the components described above are given the same or similar reference numerals, and different components are mainly described.

The detection unit 5 in this fifth embodiment is a millimeter wave radar, a distance measurement sensor that is not dependent on visible light and is equipped in the vehicle, and generates and acquires information regarding the type and position of an object as a result of object detection. The determination of the type of object by the millimeter wave radar can be realized by conventional technology such as micro Doppler. Pedestrians have a characteristic way of moving as they walk, so the movement of their hands and feet appears as a Doppler shift in the frequency components of the exploration waves reflected from the pedestrian. By detecting this Doppler shift, the millimeter wave radar can determine not only relatively stationary objects, relatively moving objects, and unidentified objects, but also pedestrians.

The control unit 13 determines the type of object based on the object information of the imaging unit 3 acquired by the acquisition unit 12 and the object detection result acquired by the detection unit 5 (a millimeter wave radar in this embodiment 5). Figure 16 is a diagram for explaining an example of the determination by the control unit 13 according to this embodiment 5. Figure 16 illustrates a vehicle 37, an object 38a which is a road sign, an object 38b which is a pedestrian, an illumination area 39 indicated by a thick line, and a detection area 40.

Generally, the illumination area 39 illuminated by the headlights 4 is different from the area in which the control unit 13 can detect objects based on object information, but for simplicity, they are considered to be the same here. The detection area 40 is the area in which the millimeter wave radar, which is the detection unit 5, can detect objects. Here, the millimeter wave radar, which is the detection unit 5, can determine at least stationary objects, moving objects, unidentified objects, and pedestrians.

When the headlights 4 start to be turned on, the acquisition unit 12 acquires object information from the imaging unit 3 and the detection results from the detection unit 5, and the control unit 13 determines the type of object based on the object information from the imaging unit 3 and the detection results from the detection unit 5.

For example, when visibility is good, the control unit 13 determines that the object 38a is a road sign and the object 38b is a pedestrian based on the object information from the imaging unit 3, and if the reliability of the determination based on the object information is greater than a threshold, illumination is performed in the same manner as in embodiment 1.

For example, assume that due to mildly poor visibility caused by weather, the control unit 13 has determined that the object 38a is a road sign and the object 38b is a pedestrian based on the object information of the imaging unit 3, but the reliability of the determination based on the object information is below a threshold. In this assumed case, if the detection result of the detection unit 5 indicates that the object 38a is unidentified and the object 38b is a pedestrian, the control unit 13 gradually increases the illumination of the headlights 4 up to brightness B5 to illuminate the object 38a, and gradually increases the illumination of the headlights 4 up to brightness B3 in FIG. 2 to illuminate the object 38b. Note that brightness B5 is set to a brightness that does not cause problems such as glare, regardless of the type of object.

In addition to the above assumed case where the reliability of the judgment based on the object information of the imaging unit 3 is equal to or lower than the threshold, if the detection result of the detection unit 5 indicates that no object is present, the control unit 13 judges that the judgment based on the object information is incorrect. Then, the control unit 13 illuminates the

objects

38a and 38b with the same brightness as the illumination area where no object is detected.

For example, if the control unit 13 is unable to determine the type of object based on the object information from the imaging unit 3 due to severe poor visibility caused by weather, it illuminates the

objects

38a and 38b with a brightness that corresponds to the type of object based on the detection results from the detection unit 5.

Summary of the Fifth Embodiment
A visible light camera that captures images using visible light can identify a large number of object types, but is subject to the effects of poor visibility, etc. On the other hand, a distance measuring sensor is less susceptible to the effects of poor visibility, etc., but the number of object types that can be identified is smaller than that of a visible light camera.

In contrast, the headlamp control device 1 according to the fifth embodiment determines the type of object based on the object information acquired by the acquisition unit 12 and the information acquired by the distance measurement sensor, which is the detection unit 5. With this configuration, the camera that captures a visible light image and the distance measurement sensor can be used complementarily, thereby improving the reliability of the object type determination.

<Modification>
In the fifth embodiment, the distance measurement sensor of the detection unit 5 is a millimeter wave radar, but is not limited to this and may be a LiDAR, a ToF camera, an infrared camera, an ultrasonic sensor, or the like, and is not limited to one. In addition, the types of objects that can be detected by the distance measurement sensor are not limited to stationary objects, moving objects, unidentified objects, and pedestrians.

In addition, the detection unit 5 is not limited to a distance measurement sensor such as a millimeter wave radar, but may be a communication device that obtains information regarding the type and position of an object through communication from an external device of the vehicle using V2V technology or V2X technology.

　Visible light cameras can make judgments even when there are no other vehicles or infrastructure around the vehicle, but they are subject to the effects of poor visibility. On the other hand, V2V or V2X technology is less susceptible to the effects of poor visibility, but cannot function unless there are other vehicles or infrastructure around the vehicle. In contrast, with the configuration of the modified example described above, the camera that captures visible light images and the communication device can be used in a complementary manner, thereby increasing the reliability of object type judgment.

<Other Modifications>
The acquisition unit 12 and the control unit 13 in FIG. 1 described above will be hereinafter referred to as "acquisition unit 12, etc." The acquisition unit 12, etc. are realized by a processing circuit 81 shown in FIG. 17. That is, the processing circuit 81 includes an acquisition unit 12 that acquires object information related to an object from a camera when an object exists in an area illuminated by the headlights of a vehicle, and a control unit 13 that illuminates the object with the headlights at a brightness corresponding to the type of the object based on the object information while gradually increasing the brightness of the above-mentioned area with the headlights. The processing circuit 81 may be implemented with dedicated hardware, or may be implemented with a processor that executes a program stored in a memory. Examples of the processor include a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, and a DSP (Digital Signal Processor).

When the processing circuit 81 is dedicated hardware, the processing circuit 81 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination of these. Each function of each unit such as the acquisition unit 12 may be realized by a circuit with distributed processing circuits, or the functions of each unit may be realized together by a single processing circuit.

When the processing circuit 81 is a processor, the functions of the acquisition unit 12 and the like are realized in combination with software and the like. The software and the like includes, for example, software, firmware, or software and firmware. The software and the like is written as a program and stored in a memory. As shown in FIG. 18, the processor 82 applied to the processing circuit 81 realizes the functions of each part by reading and executing a program stored in the memory 83. That is, the headlight control device 1 includes a memory 83 for storing a program that, when executed by the processing circuit 81, results in the execution of the steps of acquiring object information about the object from a camera when an object is present in an area illuminated by the vehicle's headlights, and illuminating the object with the headlights at a brightness corresponding to the type of object based on the object information while gradually increasing the brightness of the area by the headlights. In other words, this program can be said to cause a computer to execute the procedures and methods of the acquisition unit 12 and the like. Here, memory 83 may be, for example, non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), HDD (Hard Disk Drive), magnetic disk, flexible disk, optical disk, compact disk, mini disk, DVD (Digital Versatile Disc), drive devices for these, or any storage medium to be used in the future.

The above describes a configuration in which the functions of the acquisition unit 12, etc. are realized either by hardware or software, etc. However, this is not limited to this, and a configuration in which part of the acquisition unit 12, etc. is realized by dedicated hardware and another part is realized by software, etc. For example, the function of the acquisition unit 12 can be realized by a processing circuit 81 as dedicated hardware, and the other functions can be realized by the processing circuit 81 as a processor 82 reading and executing a program stored in a memory 83.

As described above, the processing circuit 81 can realize each of the above-mentioned functions through hardware, software, etc., or a combination of these.

In addition, each embodiment and each modified example can be freely combined, and each embodiment and each modified example can be modified or omitted as appropriate.

The above description is illustrative in all respects and is not limiting. It is understood that countless variations not illustrated can be envisioned.

1 Headlight control device, 3 Imaging unit, 4 Headlight, 12 Acquisition unit, 13 Control unit, 13a Danger determination unit, 31 Other vehicles, 32 Road signs, 33 Pedestrians, 37 Vehicles, 38 Objects.

Claims

an acquisition unit that acquires object information relating to an object from a camera when the object is present in an area illuminated by the vehicle headlights;
and a control unit that illuminates the object with the headlight at a brightness corresponding to a type of the object based on the object information while gradually increasing the brightness of the area with the headlight.
The headlamp control device according to claim 1,
The control unit increases the brightness of the area linearly or stepwise.
The headlamp control device according to claim 1,
The control unit controls the headlight to illuminate the area at a predetermined brightness.
The headlamp control device according to claim 1,
The acquisition unit further acquires an illuminance of the object illuminated by the headlight,
The control unit feedback-controls the headlamp based on the acquired illuminance and a predetermined illuminance.
The headlamp control device according to claim 1,
A headlamp control device, wherein the brightness corresponding to the type of the object when the type of the object is a person is greater than the brightness corresponding to the type of the object when the type of the object is a sign.
The headlamp control device according to claim 5,
The control unit, when it is determined based on the object information that the type of the object is a vehicle other than the vehicle, does not illuminate the other vehicle with the headlights.
The headlamp control device according to claim 1,
a risk determination unit that determines whether or not there is a predetermined possibility of a collision between the vehicle and the object,
The control unit increases or cancels the upper limit value of the brightness corresponding to the type of the object for which the object is determined to have the possibility of collision.
The headlamp control device according to claim 7,
The control unit increases the brightness corresponding to the type of the object for which the object is determined to have the possibility of collision in a stepwise manner to the upper limit value or the brightness of the area.
The headlamp control device according to claim 1,
The control unit is
A headlamp control device that, when it is detected that the object is present farther away than the area relative to the vehicle, darkens the brightness of a portion of the area into which the object will enter in the future.
The headlamp control device according to claim 1,
A headlight control device, wherein the control unit determines the type of the object based on the object information acquired by the acquisition unit, information acquired by a distance measuring sensor, or information acquired via communication from an external device of the vehicle.
When an object is present in an area illuminated by the vehicle's headlights, object information relating to the object is acquired from a camera;
The headlight control method includes illuminating the object with the headlight at a brightness corresponding to a type of the object based on the object information while gradually increasing the brightness of the area with the headlight.