Light control device, light control system, and light control method

Abstract

The purpose of the present disclosure is to provide a technique for transmitting information by using a light of a vehicle without generating flickering. A light control device (101) comprises: an information acquisition unit (11) that acquires notification information pertaining to a target vehicle or a driver of the target vehicle; a pattern conversion unit (12) that converts the notification information into a corresponding two-dimensional display pattern; and a light control unit (13) that causes a light device (23) of the target vehicle to irradiate the display pattern. The continuous irradiation time of the display pattern is equal to or greater than the time resolution of a camera (22) mounted on a non-target vehicle that is irradiated with the display pattern, and less than the temporal resolution of the human eye.

Description

Light control device, light control system, and light control method

[0001] The present disclosure relates to a technique for controlling vehicle lights.

[0002] In the past, there have been technologies for transmitting information to other vehicles using vehicle lights. For example, Patent Literature 1 discloses a configuration for notifying other vehicles of the type of vehicle by irradiating a flashing pattern determined for each type of vehicle from a vehicle's lighting device.

[0003] Japanese Patent Application Laid-Open No. 2008-269447

[0004] In the configuration of Patent Document 1, the lighting device outputs a light that flashes at 1 / 15 second intervals. Therefore, it takes (1 / 15) x 6 = 0.4 seconds to transmit 6 bits of information. Furthermore, in the example of a flashing pattern corresponding to the type of emergency vehicle, it takes 3 bits, or 0.2 seconds, for the light to be off. Because it takes time to transmit information, there is a problem in that the light flickers for drivers of other vehicles.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a technology for transmitting information using vehicle lights without causing flickering.

[0006] The lighting control device disclosed herein includes an information acquisition unit that acquires notification information regarding a target vehicle or the driver of the target vehicle, a pattern conversion unit that converts the notification information into a corresponding two-dimensional display pattern, and a lighting control unit that causes the lighting device of the target vehicle to emit the display pattern, and the continuous illumination time of the display pattern is within a time period that is equal to or greater than the time resolution of a camera mounted on a non-target vehicle that is illuminated by the display pattern and is less than the time resolution of the human eye.

[0007] The light control device of the present disclosure causes the light device to continuously project a two-dimensional display pattern within a time period that is equal to or greater than the time resolution of a camera and less than the time resolution of the human eye, thereby enabling information to be transmitted without flickering. Objects, features, aspects, and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings.

[0008] 1 is a block diagram showing the configuration of a light control system. FIG. 2 is a block diagram showing the configuration of a light control device. FIG. 3 is a flowchart showing the operation of the light control device. FIG. 4 is a diagram showing the illumination range of a headlight and the illumination range of a display pattern. FIG. 5 is a diagram showing a display pattern in negative mode. FIG. 6 is a diagram showing a display pattern in negative mode. FIG. 7 is a diagram showing a display pattern in negative mode. FIG. 8 is a diagram showing a display pattern in positive mode. FIG. 9 is a diagram showing a display pattern in positive mode. FIG. 10 is a diagram showing a display pattern in negative + positive mode. FIG. 11 is a diagram showing a display pattern in negative + positive mode. FIG. 12 is a diagram showing a display pattern in negative + positive mode. FIG. 13 is a diagram showing an image captured by a camera of the area in front of a target vehicle. FIG. 14 is a diagram showing a radiation intensity reduction process for right-hand drive vehicles. FIG. 15 is a diagram showing a radiation intensity reduction process for left-hand drive vehicles. FIG. 16 is a diagram showing a brightness compensation process for increasing the brightness of a portion adjacent to a display pattern. FIG. 17 is a diagram showing a brightness compensation process for increasing the brightness of a portion adjacent to a display pattern. FIG. 18 is a diagram showing a brightness compensation process by duty control. FIG. 19 is a diagram showing the hardware configuration of a light control device. FIG. 19 is a diagram showing the hardware configuration of a light control device.

[0009] <A. First Embodiment> <A-1. Configuration> Fig. 1 is a block diagram showing a light control system 1001 and other configurations according to the first embodiment. The light control system 1001 is made up of a light control device 101 mounted on each of a plurality of vehicles V1 and V2. The light control device 101 mounted on each of the vehicles V1 and V2 has the same configuration. Furthermore, although Fig. 1 shows two vehicles V1 and V2, a light control device 101 may be provided on each of three or more vehicles.

[0010] For the light control device 101 mounted on the vehicle V1, the vehicle V1 on which the light control device 101 is mounted is referred to as a target vehicle, and the other vehicle V2 is referred to as a non-target vehicle. Similarly, for the light control device 101 mounted on the vehicle V2, the vehicle V2 is referred to as a target vehicle, and the vehicle V1 is referred to as a non-target vehicle.

[0011] Since the configurations of vehicles V1 and V2 are similar, the configuration of vehicle V1 will be described below. In addition to a light control device 101, vehicle V1 is equipped with an information device 21, a camera 22, and a lighting device 23. The light control device 101 is connected to the information device 21, the camera 22, and the lighting device 23 and is configured to be able to use these. The light control device 101 controls the lighting device 23.

[0012] The information device 21 detects information that the vehicle V1 wants to notify to the outside of the vehicle V1 (hereinafter referred to as "notification information") and transmits the information to the light control device 101. The notification information includes notification information about the vehicle V1 (hereinafter referred to as "vehicle information") and notification information about the driver (hereinafter referred to as "driver information").

[0013] The vehicle information may include information regarding the position of the steering wheel of the vehicle V1. That is, the vehicle information may include information regarding whether the vehicle V1 is a right-hand drive vehicle or a left-hand drive vehicle. The vehicle information may also include information regarding the class of the vehicle V1, such as a passenger car, truck, or bus. Furthermore, the vehicle information may include information regarding the position, speed, or direction of travel of the vehicle V1.

[0014] The driver information may include information about the seating position of the driver of the vehicle V1. The information about the seating position of the driver is represented, for example, by information about the driver's height from the ground. The driver information may also include information about the driver's perception of dazzle. The information device 21 can detect the driver information using, for example, a DMS (Driver Monitoring System).

[0015] The camera 22 captures an image of the display pattern of the lighting device 23 of the vehicle V2, which is a non-target vehicle. The camera 22 is also used to confirm the position of the vehicle V2.

[0016] The lighting devices 23 include, for example, at least one of headlights, auxiliary lights, and taillights of the vehicle V1. The lighting devices 23 receive instructions from the lighting control device 101 and irradiate the display patterns generated by the lighting control device 101. The lighting devices 23 have an ADB (Adaptive Driving Beam) function that independently irradiates multiple ranges.

[0017] Fig. 2 is a block diagram showing the configuration of the light control device 101. The configuration of the light control device 101 mounted on the vehicle V1 will be described below with reference to Fig. 2. The light control device 101 is configured to include an information acquisition unit 11, a pattern conversion unit 12, a light control unit 13, a notification information conversion unit 14, and a non-target vehicle determination unit 15.

[0018] The information acquisition unit 11 acquires notification information from the information device 21 .

[0019] The pattern conversion unit 12 acquires notification information from the information acquisition unit 11 and converts the notification information into a corresponding two-dimensional display pattern. The correspondence between the notification information and the display pattern is predetermined. The display pattern may be any of letters, numbers, or symbols, or a combination of these. The display pattern may also be an icon or a two-dimensional barcode. When a two-dimensional barcode is used as the display pattern, detailed information such as the driver's height from the ground can also be displayed.

[0020] The notification information conversion unit 14 analyzes the image captured by the camera 22 and interprets the meaning of the display pattern included in the captured image. When a display pattern is projected from the lighting device 23 of the vehicle V2 toward the vehicle V1, the display pattern is included in the image captured by the camera 22 of the vehicle V1. The notification information conversion unit 14 interprets the meaning of the display pattern projected from the vehicle V2 and acquires the notification information represented by the display pattern.

[0021] The non-target vehicle determination unit 15 determines the direction of the non-target vehicle to which the notification information is to be transmitted, i.e., vehicle V2. In the example of Fig. 2, the non-target vehicle determination unit 15 determines the direction of vehicle V2 included in the captured image by analyzing the image captured by camera 22. However, the non-target vehicle determination unit 15 is not limited to the camera 22, and it is sufficient if it can obtain detection information regarding the direction of the non-target vehicle from any detection device mounted on the target vehicle, and can project a display pattern toward the non-target vehicle based on the detection information.

[0022] The light control unit 13 controls the lighting device 23 to emit the display pattern converted by the pattern conversion unit 12 toward the vehicle V2. The lighting device 23 does not steadily emit the display pattern, but instead repeatedly emits and does not emit the display pattern. In other words, the lighting device 23 transitions between a first state in which the display pattern is not emitted and a second state in which the display pattern is emitted. However, the lighting device 23 may emit the display pattern only once.

[0023] The duration of the second state per one lighting device 23, i.e., the continuous illumination period of the display pattern per one lighting device 23, is equal to or greater than the time resolution of the camera mounted on the non-target vehicle but less than the time resolution of the human eye. For example, if the time resolution of the camera mounted on the non-target vehicle is 33 ms, the continuous illumination period of the display pattern is equal to or greater than 33 ms but less than 50 ms. Therefore, when a display pattern is illuminated from the lighting device 23 of vehicle V1 toward vehicle V2, the driver of vehicle V2 will not be able to see the display pattern, but the camera 22 mounted on vehicle V2 will be able to capture it. Because the display pattern of this embodiment is a two-dimensional display pattern rather than a flashing pattern, it is possible to transmit information in a short period of time.

[0024] In addition to the illumination process of the display pattern, the light control unit 13 also controls the illumination range of the lighting device 23 based on notification information from non-target vehicles (see Figures 15 and 16).

[0025] <A-2. Operation> Fig. 3 is a flowchart showing the operation of the light control device 101. The operation of the light control device 101 will be described below in accordance with the flow of Fig. 3.

[0026] First, in step S101, the pattern conversion unit 12 converts the notification information acquired by the information acquisition unit 11 into a display pattern corresponding to the notification information.

[0027] Next, in step S102, the non-target vehicle determination unit 15 analyzes the image captured by the camera 22 to determine the position of the non-target vehicle, and determines the projection direction of the display pattern so that the display pattern is projected onto the non-target vehicle.

[0028] 4 shows how a display pattern is irradiated from the headlight 24, which is the lighting device 23 of the vehicle V1, toward the vehicle V2. A part of the entire illumination range R1 of the headlight 24 is an illumination range R2 of the display pattern.

[0029] Then, in step S103, the light control unit 13 determines whether the current state of the headlights 24 of the target vehicle is a fully lit state. The current state of the headlights 24, in which no display pattern is emitted, corresponds to the first state of the headlights 24. Then, the light control unit 13 determines the illumination mode in the second state, in which the display pattern is emitted, according to the first state of the headlights 24. In other words, the display pattern changes according to the first state of the lighting device 23.

[0030] The full lighting state means that the headlights 24 are in a lighting state over their entire illumination range. If the headlights 24 are in a full lighting state in step S103, the light control unit 13 causes the headlights 24 to illuminate a display pattern in negative mode in step S105.

[0031] 5 to 7 show examples of display patterns P in negative mode. The lighting device 23 has a plurality of illumination areas shown in a grid pattern in FIGS. 5 to 7, and it is possible to control whether each illumination area is turned on or off. In negative mode, some illumination areas of the lighting device 23 are turned off, and the display pattern P is drawn by the turned-off illumination areas. FIG. 5 shows a display pattern P of "L" representing a left-hand drive vehicle. FIG. 6 shows a display pattern P of "R" representing a right-hand drive vehicle. FIG. 7 shows a display pattern P of "G" representing that the driver is sensitive to glare.

[0032] If the headlights 24 are not in a fully lit state in step S103, the light control unit 13 determines whether the headlights 24 are currently in an off state. An off state means that the headlights 24 are not lit in their entire illumination range. If the headlights 24 are in an off state in step S104, the light control unit 13 causes the headlights 24 to emit a display pattern in positive mode in step S106.

[0033] 8 to 10 show examples of display patterns P in positive mode. In positive mode, a portion of the illumination range of the lighting device 23 is lit, and the display pattern P is drawn by the lit illumination range. Fig. 8 shows the display pattern P for "L". Fig. 9 shows the display pattern P for "R". Fig. 10 shows the display pattern P for "G".

[0034] If the headlights 24 are not in the off state in step S104, the headlights 24 are currently in a partially on state. A partially on state means that the headlights 24 are in a partly on state in the illumination range and in a partly off state in the illumination range. In this case, the light control unit 13 causes the headlights 24 to illuminate the display pattern in the negative + positive mode in step S107.

[0035] 11 to 13 illustrate display patterns P in the negative + positive mode. In the negative + positive mode, a portion of the illuminated area that was unlit in the first state is switched to illuminated, and the display pattern P is drawn by the switched illuminated area. FIG. 11 shows the display pattern P for "L." FIG. 12 shows the display pattern P for "R." FIG. 13 shows the display pattern P for "G."

[0036] In any of steps S105 to S107, the display pattern P is projected from the target vehicle toward the non-target vehicle. However, the continuous projection time of the display pattern P is equal to or longer than 33 ms and shorter than 50 ms, and the headlamp 24 alternates between the first state and the second state.

[0037] Next, in step S108, the notification information conversion unit 14 determines whether the driver of the non-target vehicle is experiencing dazzling. Specifically, the notification information conversion unit 14 analyzes the video captured by the camera 22 and interprets the meaning of the display pattern included in the captured video, i.e., converts the display pattern into corresponding notification information. The display pattern included in the video captured by the camera 22 is a display pattern irradiated from the non-target vehicle toward the target vehicle.

[0038] If the display pattern projected onto the target vehicle means "the driver is dazzled," the notification information conversion unit 14 determines that the driver of the non-target vehicle is dazzled. If it is not determined in step S108 that the driver of the non-target vehicle is dazzled, the lighting control device 101 ends the process.

[0039] If it is determined in step S108 that the driver of the non-target vehicle is experiencing dazzling light, then in step S109 the notification information conversion unit 14 determines whether the non-target vehicle has a right-hand drive. Specifically, the notification information conversion unit 14 analyzes the video captured by the camera 22, interprets the meaning of the display pattern included in the captured video, and if the display pattern projected on the target vehicle means a "right-hand drive," determines that the non-target vehicle has a right-hand drive.

[0040] The display pattern determined by the notification information conversion unit 14 in step S108 and the display pattern determined by the notification information conversion unit 14 in step S109 may be irradiated simultaneously from one non-target vehicle, or may be irradiated at different times. That is, for example, a display pattern of "RG" may be irradiated from a non-target vehicle to a target vehicle, or the display pattern of "R" and the display pattern of "G" may be displayed alternately.

[0041] Fig. 14 shows an image captured by the camera 22 used for the determinations in steps S108 and S109. In the example of Fig. 14, three non-target vehicles, vehicles V3, V4, and V5, are captured. Vehicles V3 and V4 are traveling in the oncoming lane of the target vehicle in a direction approaching the target vehicle, while vehicle V5 is traveling ahead in the same lane as the target vehicle. The headlights 24 of vehicle V3 emit an "R" display pattern P, indicating a right-hand drive vehicle, and the headlights 24 of vehicle V4 emit an "L" display pattern P, indicating a left-hand drive vehicle. Furthermore, the taillights 25 of vehicle V5 emit a "G" display pattern P, indicating that the driver is feeling dazzled.

[0042] If the non-target vehicle has a right-hand drive in step S109, the lighting control unit 13 performs a radiance reduction process in step S110 to reduce the radiance of the portion of the illumination range of the lighting device 23 that corresponds to the right-hand driver's seat of the non-target vehicle.

[0043] 15 shows an example of the radiance reduction process for vehicle V3. The radiance reduction process reduces the radiance of a portion S3 of vehicle V3 that corresponds to driver D3. This allows vehicle V3 to be illuminated while reducing the glare experienced by driver D3.

[0044] If the non-target vehicle is not a right-hand drive vehicle in step S110, the lighting control unit 13 performs a radiance reduction process in step S111 to reduce the radiance of the part of the illumination range of the lighting device 23 that corresponds to the left driver's seat of the non-target vehicle.

[0045] 16 shows an example of the radiance reduction process for vehicle V4. The radiance reduction process is performed to reduce the radiance of a portion S4 of vehicle V4 that corresponds to driver D4. This allows the vehicle V4 to be illuminated while reducing the glare experienced by driver D4.

[0046] <A-3. Effects> As described above, the light control device 101 according to the first embodiment includes an information acquisition unit 11, a pattern conversion unit 12, and a light control unit 13. The information acquisition unit 11 acquires notification information related to a target vehicle or a driver of the target vehicle. The pattern conversion unit 12 converts the notification information into a corresponding two-dimensional display pattern. The light control unit 13 causes the lighting device 23 of the target vehicle to emit a display pattern. The continuous illumination time of the display pattern is equal to or greater than the time resolution of a camera mounted on a non-target vehicle that receives the illumination of the display pattern and is less than the time resolution of the human eye. Because the light control device 101 emits a two-dimensional display pattern within the extremely short time period described above, the display pattern is not visible to the driver of the non-target vehicle and can be detected by the camera of the non-target vehicle. Therefore, information can be transmitted using the vehicle's lights without flickering.

[0047] <B. Second Embodiment> <B-1. Configuration> The configurations of the light control system 1002 and the light control device 102 according to the second embodiment are the same as the configurations of the light control system 1001 and the light control device 101 according to the first embodiment, as shown in FIGS. 1 and 2 .

[0048] The light control device 102 differs from the light control device 101 according to embodiment 1 in that the light control unit 13 also functions as a brightness compensation unit that compensates for the brightness of the light device 23 that decreases due to the illumination of the display pattern.

[0049] <B-2. Operation> When the first state of the lighting device 23 is the fully lit state, the display pattern is illuminated in the negative mode in the second state of the lighting device 23, as shown in Figures 5 to 7. In this case, if the brightness of the illuminated area that is lit in the second state does not change from the first state, the brightness of the entire illuminated area in the second state will be lower than in the first state.

[0050] Therefore, the light control unit 13 performs a process to compensate for this decrease in brightness. The first method of compensating for the decrease in brightness is to increase the brightness of a portion Q of the illumination range adjacent to the display pattern P in the second state of the lighting device 23 to be higher than the brightness of the portion Q in the first state. Figures 17 to 19 show the portion Q adjacent to the display pattern P.

[0051] The second method for compensating for the decrease in brightness is to control the lighting duty of the lighting device 23. In this example, the light control unit 13 controls the lighting device 23 using PWM (Pulse Width Modulation). FIG. 20 shows pulses in PWM control of the lighting device 23. Pulses P21-P27 are arranged in chronological order, and pulses P23-P25 are pulses when the headlight 24 is in the second state, i.e., when the display pattern is irradiated. Pulses P21, P22, P26, and P27 are pulses when the headlight 24 is in the first state, i.e., when the display pattern is not irradiated.

[0052] In the second state, the display pattern is illuminated in negative mode, so the amplitude of pulses P23-P25 is smaller than the amplitude of pulses P21, P22, P26, and P27 in the first state. Accordingly, the light control unit 13 sets the width of pulses P23-P25, i.e., the lighting duty, to t2 = t1 + Δt, which is larger than the lighting duty t1 of pulses P21 and P27 in the first state. This suppresses a decrease in brightness of the headlamp 24 in the second state.

[0053] Furthermore, if adjusting the lighting duty of the pulses P23-P25 in the second state alone is not sufficient to compensate for brightness, the light control unit 13 may adjust the lighting duty of at least one pulse in the first state that is adjacent to or before or after the pulses P23-P25 in the second state. In the example of FIG. 20, the lighting duty of one pulse P22 adjacent to and before the pulses P23-P25 and one pulse P26 adjacent to and after the pulses P23-P25 is set to t2, which is greater than t1. The light control unit 13 may increase the lighting duty of the pulse in the first state to t2 only either before or after the pulses P23-P25. This makes it possible to make the reduction in brightness of the headlamp 24 in the second state less noticeable.

[0054] <B-3. Effects> The light control device 102 according to the second embodiment includes a brightness compensation unit that compensates for the reduction in brightness of the light 23 due to the illumination of the display pattern when the first state of the light 23 of the target vehicle is the fully illuminated state. Therefore, it is possible to suppress the reduction in brightness of the light 23 due to the illumination of the display pattern.

[0055] <C. Hardware Configuration> The information acquisition unit 11, pattern conversion unit 12, light control unit 13, notification information conversion unit 14, and non-target vehicle determination unit 15 (hereinafter referred to as the "information acquisition unit 11, etc.") in the above-mentioned light control devices 101, 102 are realized by a processing circuit 81 shown in FIG. 21 . That is, the processing circuit 81 includes the information acquisition unit 11, etc. The processing circuit 81 may be implemented by dedicated hardware, or may be implemented by a processor that executes a program stored in memory. The processor may be, for example, a central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, DSP (Digital Signal Processor), etc.

[0056] When the processing circuitry 81 is dedicated hardware, the processing circuitry 81 may be, 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 thereof. Each function of each unit such as the information acquisition unit 11 may be realized by a plurality of processing circuits 81, or the functions of each unit may be realized together by a single processing circuit.

[0057] When the processing circuit 81 is a processor, the functions of the information acquisition unit 11 and the like are realized by a combination of software, etc. (software, firmware, or software and firmware). The software, etc. is written as a program and stored in a memory. As shown in FIG. 22 , the processor 82 applied to the processing circuit 81 realizes the functions of each unit by reading and executing a program stored in a memory 83. That is, the light control device 101, 102 includes a memory 83 for storing a program that, when executed by the processing circuit 81, results in the function of the information acquisition unit 11 and the like being executed. In other words, this program can be said to cause a computer to execute the procedure or method of the information acquisition unit 11 and the like. Here, the memory 83 may be, for example, a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), or an EEPROM (Electrically Erasable Programmable Read Only Memory), a HDD (Hard Disk Drive), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD (Digital Versatile Disk) and its drive device, or any storage medium that will be used in the future.

[0058] The above describes a configuration in which each function of the information acquisition unit 11, etc. is realized either by hardware or software, etc. However, the present invention is not limited to this, and a configuration in which part of the information acquisition unit 11, etc. is realized by dedicated hardware and another part is realized by software, etc. For example, the function of the light control unit 13 can be realized by a processing circuit as dedicated hardware, and the other functions can be realized by the processing circuit 81 as the processor 82 reading and executing programs stored in the memory 83.

[0059] As described above, the processing circuit can realize the above-mentioned functions by hardware, software, or a combination of these. Note that the storage units are configured with memory 83, but they may be configured with a single memory 83, or each may be configured with a separate memory.

[0060] Furthermore, although the light control devices 101 and 102 have been described above as in-vehicle devices, they can also be applied to a system constructed by appropriately combining a PND (Portable Navigation Device), a communication terminal (for example, a mobile terminal such as a mobile phone, smartphone, or tablet), the functions of applications installed thereon, a server, etc. In this case, the functions or components of the light control devices 101 and 102 described above may be distributed among the devices that construct the system, or may be concentrated in one of the devices.

[0061] It should be noted that the embodiments can be freely combined, and each embodiment can be modified or omitted as appropriate. The above description is an example in all respects. It is understood that countless variations not illustrated can be envisioned.

[0062] REFERENCE SIGNS LIST 11 Information acquisition unit, 12 Pattern conversion unit, 13 Light control unit, 14 Notification information conversion unit, 15 Non-target vehicle determination unit, 21 Information device, 22 Camera, 23 Lighting device, 24 Headlight, 25 Taillight, 81 Processing circuit, 82 Processor, 83 Memory, 101, 102 Lighting control device, 1001, 1002 Lighting control system.

Claims

1. An information acquisition unit that acquires notification information regarding a target vehicle or a driver of the target vehicle, a pattern conversion unit that converts the notification information into a corresponding two-dimensional display pattern, and a lighting control unit that irradiates the display pattern onto a lighting device of the target vehicle, wherein a continuous irradiation time of the display pattern is within a time that is equal to or greater than a time resolution of a camera mounted on a non-target vehicle that receives irradiation of the display pattern and less than a time resolution of a human eye. A lighting control device.

2. The lighting control device according to claim 1, wherein the lighting control unit irradiates the display pattern toward the non-target vehicle based on detection information of the non-target vehicle by a detection device mounted on the target vehicle.

3. The lighting control device according to claim 1 or claim 2, wherein the lighting device of the target vehicle transitions between a first state in which the display pattern is not irradiated and a second state in which the display pattern is irradiated, the first state of the lighting device includes a full lighting state in which the entire irradiation range of the lighting device is lit and a lighting-off state in which the entire irradiation range of the lighting device is turned off, and the display pattern changes according to the first state of the lighting device.

4. The lighting control device according to claim 3, wherein when the first state of the lighting device of the target vehicle is the full lighting state, the display pattern is a negative-mode pattern depicted by a partially turned-off irradiation range of the lighting device.

5. The lighting control device according to claim 3, wherein when the first state of the lighting device of the target vehicle is the lighting-off state, the display pattern is a positive-mode pattern depicted by a partially lit irradiation range of the lighting device.

6. The lighting control device according to claim 3, wherein the lighting device of the target vehicle includes a headlight of the target vehicle, and the first state of the headlight includes a partial lighting state in which only a partial irradiation range of the headlight is lit in addition to the full lighting state and the lighting-off state.

7. The lighting control device according to claim 6, wherein when the first state of the lighting device of the target vehicle is the partial lighting state, the display pattern is a negative + positive-mode pattern depicted by a partial irradiation range that switches from lighting-off in the first state to lighting-on in the second state.

8. The lighting control device according to claim 4, further comprising a luminance compensation unit that compensates for the luminance of the lighting device of the target vehicle that decreases due to the irradiation of the display pattern when the first state of the lighting device of the target vehicle is the full-on state.

9. The lighting control unit performs PWM control on the lighting device, and when the first state of the lighting device of the target vehicle is the full-on state, the luminance compensation unit makes the lighting duty in the second state of the lighting device greater than the lighting duty in the first state. The lighting control device according to claim 8.

10. The lighting control unit performs PWM control on the lighting device, and when the first state of the lighting device of the target vehicle is the full-on state, the luminance compensation unit makes the lighting duty of at least one pulse in the first state greater than the lighting duty of other pulses in the first state for at least one of before or after the second state of the lighting device. The lighting control device according to claim 9.

11. The luminance compensation unit increases the luminance of a portion adjacent to the display pattern in the irradiation range in the second state to be higher than the luminance in the first state when the first state of the lighting device of the target vehicle is the on state. The lighting control device according to claim 8.

12. A notification information conversion unit that converts the display pattern irradiated from the lighting device of a non-target vehicle into corresponding notification information based on a captured image captured by the camera mounted on the target vehicle, and the lighting control unit controls the lighting device of the target vehicle based on the notification information corresponding to the display pattern irradiated from the lighting device of the non-target vehicle. The lighting control device according to claim 1.

13. When the notification information converted from the display pattern includes information on the steering wheel position of the non-target vehicle, the lighting control unit performs a radiation intensity reduction process of reducing the radiation intensity of a range corresponding to an area that is narrower than the entire non-target vehicle and includes the steering wheel position of the non-target vehicle in the irradiation range of the lighting device irradiating the non-target vehicle to be lower than other ranges. The lighting control device according to claim 12.

14. When the notification information converted from the display pattern includes information indicating that the driver of the non-target vehicle feels dazzled, the lighting control unit performs the radiation intensity reduction process. The lighting control device according to claim 13.

15. A lighting control method, comprising: obtaining notification information regarding a target vehicle or a driver of the target vehicle; converting the notification information into a corresponding two-dimensional display pattern; irradiating the display pattern onto a lighting device of the target vehicle; and the continuous irradiation time of the display pattern being within a time that is equal to or greater than the time resolution of a camera mounted on a non-target vehicle receiving the irradiation and less than the time resolution of a human eye.

16. The lighting control method according to claim 15, comprising: converting the display pattern irradiated from a lighting device of a non-target vehicle into the corresponding notification information based on a captured image captured by a camera mounted on the target vehicle; and controlling the lighting device of the target vehicle based on the notification information corresponding to the display pattern irradiated from the lighting device of the non-target vehicle.

17. A lighting control system comprising a plurality of lighting control devices respectively mounted on a plurality of vehicles each equipped with a camera, each lighting control device comprising: an information acquisition unit configured to acquire notification information regarding a target vehicle or a driver of the target vehicle; a pattern conversion unit configured to convert the notification information into a corresponding two-dimensional display pattern; a lighting control unit configured to irradiate the display pattern onto a lighting device of the target vehicle; and a notification information conversion unit configured to convert the display pattern irradiated from a lighting device of a non-target vehicle into the corresponding notification information based on a captured image captured by the camera mounted on the target vehicle, the continuous irradiation time of the display pattern being within a time that is equal to or greater than the time resolution of a camera mounted on a non-target vehicle receiving the irradiation and less than the time resolution of a human eye, and the lighting control unit controlling the lighting device of the target vehicle based on the notification information corresponding to the display pattern irradiated from the lighting device of the non-target vehicle.

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