JP2022144915A - Lighting control device of vehicle - Google Patents

Abstract

To suppress deterioration in visibility of road conditions in front of a vehicle by improving visibility of a driver.SOLUTION: A lighting control device of a vehicle has an ECU for controlling an HUD 10 for calculating a luminance gradient formed by a headlight and displaying an image by a virtual image. In an annular region CA in a predetermined angle range in a radiation direction centering on a gazing point FP of a driver, when a ratio of a predetermined gradient region that has a predetermined gradient in which a luminance gradient heading a radiation direction from an outer edge position of the annular region CA to an inner edge position decreases at a specific ratio is less than a predetermined ratio, the ECU displays an image in which the luminance gradient becomes a predetermined gradient at a portion overlapping with the annular region CA in a front window glass 1.SELECTED DRAWING: Figure 14

Description

The technology disclosed herein belongs to the technical field related to vehicle lighting control devices.

2. Description of the Related Art Conventionally, technologies have been proposed that enable a driver to recognize road conditions in an environment in which the driver's visibility of a vehicle is poor, such as at night in the rain.

For example, in Patent Document 1, when the vehicle is turning, a driver gaze point angle is calculated from a vehicle speed and a lateral G assumed value, and an angle corresponding to this driver gaze point angle is set as a target swivel angle. A vehicle headlamp device that tilts a lamp unit up to a swivel angle is disclosed.

JP 2005-138622 A

D. Zevagno, Some new luminance effect, Perception, 1999

By the way, the inventors of the present application conducted extensive research and found that one of the causes of deterioration in the visibility of road conditions in front of the vehicle at night or the like is that the driver's pupils become smaller due to miosis. That is, at night, ambient light such as the light from the headlights of an oncoming vehicle is incident on the driver's pupil, which causes the driver's pupil to become smaller. If the pupil becomes smaller, it becomes difficult for reflected light from the road itself to enter, so the driver's ability to see the road conditions deteriorates, and the visibility of the road conditions in front of the vehicle deteriorates. In particular, when it rains at night, the light from the headlights of oncoming vehicles is likely to be reflected on the road surface and input to the driver, which tends to deteriorate the driver's visual recognition ability.

A lighting unit capable of changing the irradiation direction as described in Patent Document 1 can be expected to improve visibility during turning. However, since the driver's visibility itself does not change, it is difficult to expect an improvement in visibility in rainy weather or the like.

The technology disclosed herein has been made in view of the above points, and its purpose is to improve the driver's visual recognition ability and to suppress the deterioration of the visibility of the road conditions in front of the vehicle. That's what it is.

In order to solve the above problems, the technology disclosed herein targets a lighting control device of a vehicle, which is positioned in front of the driver and has a display that displays a virtual image, and is illuminated by the headlights of the vehicle. a road surface luminance detector that detects the luminance of the road surface; a visual field area detection unit that detects a visual field area of the driver of the vehicle; a luminance gradient calculation unit that calculates a luminance gradient formed by the light of the headlight; a control unit for controlling a display, wherein the control unit radiates from the outer edge position to the inner edge position of the annular area within a predetermined angular range in the radial direction centering on the gaze point of the driver. When the ratio of the predetermined gradient region where the luminance gradient in the direction decreases at a specific ratio is less than the predetermined ratio, a portion of the display that overlaps with the annular region has a luminance gradient that is equal to the predetermined gradient. It is configured to display a different image.

That is, as a result of extensive research by the inventors of the present application, a mydriatic effect can be obtained when a predetermined gradient region having a predetermined luminance gradient exists in an annular region visible to the driver around the driver's gaze point. It was found that the driver's pupil dilated when Therefore, a predetermined gradient area is provided within the annular area. Specifically, a predetermined gradient area is formed in the annular area by displaying an image with a predetermined luminance gradient on the display while realizing a luminance gradient with a predetermined gradient by the headlights. As a result, the pupil of the driver can be enlarged by appropriately obtaining a mydriatic effect. As a result, it is possible to improve the visibility of the driver and prevent deterioration of the visibility of the road conditions in front of the vehicle.

In the lighting control device for a vehicle, the control unit causes the portion of the display that overlaps with the annular region to have the luminance gradient such that the ratio of the predetermined gradient region in the annular region becomes the predetermined ratio. The configuration may be such that an image having a predetermined gradient is displayed.

Further research by the inventors of the present application revealed that if the predetermined gradient area is too narrow, a sufficient mydriatic effect cannot be obtained, while if the predetermined gradient area is too wide, the amount of light entering the driver's eyes increases. It turned out that the pupil was constricted. Therefore, by displaying an image with a predetermined luminance gradient on the display, a predetermined ratio of the predetermined gradient region is formed in the annular region. As a result, it is possible to improve the visibility of the driver and more effectively suppress the deterioration of the visibility of the road conditions in front of the vehicle.

In the vehicle lighting control device, the visual field detection unit may detect the visual field based on input signals from a driver monitor camera that photographs the driver and a front camera that photographs the front of the vehicle. good.

According to this configuration, the point of gaze of the driver can be detected with high accuracy, and as a result, the annular region in which the mydriatic effect can be obtained can be set with high accuracy. As a result, the driver's visual recognition ability can be improved more effectively.

In the vehicle lighting control device, the outer edge position of the annular region may be set between 10° and 25° in radial directions centering on the gaze point of the driver.

That is, as a result of extensive research by the inventors of the present application based on the density distribution of photoreceptors, the outer edge position of the toric region is set between 10° and 25° in the radial direction from the point of gaze of the driver. It was found that the mydriatic effect can be obtained remarkably when the Therefore, according to the above configuration, it is possible to more effectively improve the visual recognition ability of the driver.

In the vehicle lighting control device, the width of the predetermined angle range may be set to 1° to 4°.

That is, if the width of the predetermined angle range is too narrow, the amount of light is insufficient and a sufficient mydriatic effect cannot be obtained. As a result of diligent research by the inventors of the present application, it was found that if the width of the predetermined angle range is 1° to 4°, a sufficient mydriatic effect can be obtained while suppressing miosis. Therefore, according to the above configuration, it is possible to more effectively improve the visual recognition ability of the driver.

In the vehicle lighting control device, the predetermined ratio may be set to 8% to 12%.

As a result of diligent research by the inventors of the present application, it was found that a sufficient mydriatic effect can be obtained while suppressing miosis if the ratio of the predetermined gradient region in the toric region is 8% to 12%. Therefore, according to the above configuration, it is possible to more effectively improve the visual recognition ability of the driver.

In one embodiment of the vehicle lighting control device, the luminance gradient calculation unit calculates the luminance gradient of a specific area that extends in the circumferential direction of the annular area and that is set to the predetermined proportion of the entire annular area. When a portion of the specific region is the predetermined gradient region and the remainder of the specific region is not the predetermined gradient region, the control unit calculates only the portion overlapping the remainder of the specific region on the display, An image having a brightness gradient that is the predetermined gradient is displayed.

According to this configuration, since the specific area is set in advance, the predetermined gradient area can be formed in the annular area in an appropriate ratio. Further, if the specific area is set to an area where the mydriatic effect is likely to be obtained according to the point of gaze of the driver, it is possible to appropriately obtain the mydriatic effect by forming a predetermined gradient area. As a result, the driver's visual recognition ability can be improved more effectively.

In the one embodiment, the specific areas may be set in equal proportions to the left and right.

According to this configuration, the right and left pupils of the driver can be appropriately stimulated, and the mydriatic effect can be appropriately obtained for both the left and right pupils. As a result, the driver's visual recognition ability can be improved more effectively.

As described above, according to the technology disclosed herein, the pupil diameter of the driver can be increased by the mydriatic effect. As a result, it is possible to improve the visibility of the driver and prevent the visibility of the road conditions ahead of the vehicle from deteriorating.

FIG. 1 is a schematic diagram showing a vehicle equipped with a lighting control device according to exemplary embodiment 1. FIG. FIG. 2 is a schematic diagram showing the configuration of the interior of the vehicle. FIG. 3 is a front view of the vehicle. FIG. 4 is a schematic diagram showing the configuration of the headlight. FIG. 5 is a schematic diagram showing the LED arrangement of the low beam unit. FIG. 6 is a block diagram showing the configuration of the control unit. FIG. 7 is a diagram showing experimental conditions for testing the relationship between the luminance gradient and the visual recognition ability of the driver. FIG. 8 is a diagram for explaining the definition of the luminance gradient. FIG. 9 is a graph showing the relationship between the luminance gradient ratio and the pupil diameter change amount of the subject. FIG. 10 is a graph showing the relationship between the outer edge position of the toric region and the pupil diameter change amount of the subject. FIG. 11 is a graph showing the relationship between the width of the annular region and the pupil diameter change amount of the subject. FIG. 12 is a graph showing the relationship between the luminance gradient and the pupil diameter change amount of the subject. FIG. 13 is a diagram for explaining the light distribution control executed by the control unit of the lighting control device, and shows a case where the vehicle is running on a straight road. FIG. 14 is a diagram for explaining light distribution control executed by the control unit of the lighting control device, and shows a case where the vehicle is traveling on a left curve. FIG. 15 is a flowchart showing processing operations of light distribution control executed by the ECU. FIG. 16 is a diagram for explaining light distribution control executed by the ECU of the lighting control device according to the second embodiment. FIG. 17 is a flowchart showing processing operations of light distribution control executed by the ECU of the lighting control device according to the second embodiment. FIG. 18 is a flowchart showing processing operations of light distribution control executed by the ECU of the lighting control device according to the third embodiment.

Exemplary embodiments are described in detail below with reference to the drawings. In the following description, front, rear, left, right, top and bottom as viewed from the driver of the vehicle are simply referred to as front, rear, left, right, top and bottom, respectively. The front-back direction, the left-right direction, and the up-down direction are only specified for convenience in order to simplify the explanation, and do not limit the actual usage conditions.

(Embodiment 1)
<Vehicle configuration>
FIG. 1 shows a vehicle V having a lighting control device according to the first embodiment. The vehicle V is a four-wheeled automobile, and two of the four wheels (for example, the front wheels) that are symmetrically positioned are driven by a driving device (not shown). As a result, the vehicle V moves (runs).

As shown in FIG. 2, the vehicle V is a right-hand drive vehicle, and a steering wheel 8 is arranged on the right side. A front window glass 1 is arranged on the front side of the vehicle when viewed from the driver's seat in the vehicle interior. The front window glass 1 is partitioned by a plurality of vehicle components when viewed from the inside of the vehicle compartment. Specifically, the front window glass 1 is partitioned by left and right front pillar trims 2 , a roof trim 3 , and an instrument panel 4 .

The left and right front pillar trims 2 form boundaries on the outer side of the front window glass 1 in the vehicle width direction. Each front pillar trim 2 is arranged along each front pillar. As shown in FIG. 2, the front pillar trims 2 are arranged so as to be inclined upward so as to be spaced apart from each other.

The roof trim 3 forms the upper boundary of the front window glass 1 . The roof trim 3 covers the interior side of the roof panel of the vehicle. A rearview mirror 5 is attached to the center of the front window glass 1 in the vehicle width direction and a slightly lower portion of the roof trim 3 .

The instrument panel 4 constitutes the lower boundary of the windshield 1 . A meter box and a center display 7 are provided on the instrument panel 4 . A driver monitor camera 102 (see FIG. 6) is provided in the vicinity of the center display 7 to capture the interior of the vehicle, particularly the face of the driver. By arranging the driver monitor camera 102 in the vicinity of the center display 7, the driver's eyes can be photographed without being obstructed by the driver's bangs and eyelashes.

The vehicle also has a head-up display 10 (hereinafter referred to as HUD 10) as a display device that displays an image in a field of view in front of the driver. Specifically, the HUD 10 displays a virtual image on the front window glass 1 . The HUD 10 displays a virtual image of the image in a predetermined area on the front window glass 1 by projecting the image onto the front window glass 1 from below. In Embodiment 1, the display range of the HUD 10 is set to the entire front window glass 1 . The front window glass 1 and the HUD 10 are an example of a display positioned in front of the driver and displaying a virtual image.

The vehicle also has side mirrors 6 outside the left and right front pillars in the vehicle width direction. Each side mirror 6 is arranged so that the driver sitting in the driver's seat can see through the side door window.

As shown in FIG. 3, the vehicle V is provided with a plurality of cameras for photographing the external environment (only the front camera 100 is shown in FIG. 3). For example, the front camera 100 that captures the external environment in front of the vehicle is arranged at the front end of the vehicle slightly below the hood 9 of the vehicle. A plurality of cameras are also installed on both sides of the vehicle and also on the rear of the vehicle so as to take a 360° image of the surroundings of the vehicle in the horizontal direction.

The vehicle has a pair of headlights 20 on the front side and on the left and right sides. The headlight 20 illuminates the front of the vehicle V. As shown in FIG. Each headlight 20 is arranged so as to be continuous with the front fender of the vehicle V. As shown in FIG. Headlight 20 is electrically connected to battery B, as shown in FIG. The headlight 20 is lit by electric power supplied from the battery B. As shown in FIG.

As shown in FIG. 4 , the headlight 20 has a low beam unit 21 and a high beam unit 22 . The low beam unit 21 emits a low beam directed slightly downward in front of the vehicle. The low beam forms a part of the light emitted by the headlights 20 that is closer to the vehicle. The high beam unit 22 emits a high beam directed substantially horizontally in front of the vehicle. The high beam forms part of the light emitted by the headlights 20 that is on the far side of the vehicle.

The low beam unit 21 includes an LED array 23 composed of a plurality of LED light sources 23a that emit low beams, and a reflecting mirror. As shown in FIG. 5, the LED array 23 is formed by arranging a plurality of rows of LED light sources 23a arranged in the vertical direction in a plurality of rows in the lateral direction (vehicle width direction). Each LED light source 23a is configured so that the luminance can be adjusted independently. The number of columns of the LED light sources 23a is not particularly limited. The number of LED light sources 23a in each row is not particularly limited as long as there are two or more LED light sources 23a. In particular, the number of LED light sources 23a may differ in each row.

Like the low beam unit 21, the high beam unit 22 also has an LED array 24 made up of a plurality of LED light sources. The arrangement of the plurality of LED light sources in the LED array 24 may be the same as or different from the arrangement of the LED light sources 23a in the low beam unit 21a.

The headlight 20 is controlled by an ECU 30 (Electrical Control Unit). The ECU 30 is computer hardware including a processor and a memory having a plurality of modules. The ECU 30 controls the HUD 10 in addition to controlling the headlights 20 .

<Configuration of control system>
As shown in FIG. 6, the ECU 30 generates control signals for the HUD 10 and the headlights 20 based on information input from a plurality of sensors and external terminals. The ECU 30 stores information from a plurality of front cameras 100 that capture images of the front of the vehicle V, map data 101 transmitted from an external server, information from a driver monitor camera 102 that captures an area including the driver's face, A signal from a rain sensor 103 that detects whether it is raining, a signal from a wiper switch 104 that activates a wiper that wipes the front window glass 1, and a signal from a headlight switch 105 that receives a request to turn on the headlights 20. is entered. What is shown here is an example of information received by the ECU 30 , and other information may be input to the ECU 30 .

The front camera 100 acquires an image including the road surface illuminated by the headlights 20 of the vehicle V. FIG. The information of the image acquired by the front camera 100 includes the brightness of the road surface illuminated by the headlights 20 of the vehicle V. FIG. Therefore, the front camera 100 constitutes a road luminance detector.

The headlight switch 105 is provided, for example, on a winker lever. When the headlight switch 105 is turned on, the headlights 20 are operated by the headlight control unit 35, which will be described later, and the front of the vehicle V is illuminated with light.

The ECU 30 includes a luminance gradient calculator 31 that calculates the luminance gradient formed by the light from the pair of headlights 20, a road shape calculator 32 that calculates the shape of the road in front of the vehicle V, and a driver's visual field area. and a visual field area calculator 33 .

The brightness gradient calculation unit 31 calculates the brightness gradient of the light included in the driver's field of view, among the light emitted from the headlights 20 to the road surface, from the image captured by the front camera 100 . The details of the operation of the luminance gradient calculator 31 will be described later.

The road shape calculator 32 calculates the road shape ahead of the vehicle V based on the information from the front camera 100 and the map data 101 . The road geometry calculator 32 detects whether the road geometry in front of the vehicle V is straight ahead, curved to the left, curved to the right, uphill, or downhill. The road shape calculation unit 32 also calculates whether or not there are obstacles in the middle of the road or on the left and right sides of the road.

The visual field calculation unit 33 calculates the driver's visual field based on the information from the front camera 100 and the information from the driver monitor camera 102 . Specifically, the visual field calculation unit 33 detects the line of sight of the driver from the driver monitor camera 102 . The field-of-view area calculation unit 33 applies the detected line of sight of the driver to the image captured by the front camera 100 to detect the driver's gaze point FP (see FIGS. 13 and 14). Further, although the details will be described later, the visual field area calculation unit 33 calculates an annular area CA within a predetermined angular range in the radial direction centering on the point of gaze FP of the driver. For these reasons, the front camera 100, the driver monitor camera 102, and the viewing area calculation section 33 constitute a viewing area detection section.

The ECU 30 has a light distribution control section 34 for controlling the light distribution in the driver's visual field area. Details of the operation of the light distribution control unit 34 will be described later.

The ECU 30 has a headlight control section 35 that controls each headlight 20 according to a signal from the light distribution control section 34 . The ECU 30 also has a display control section 36 that controls the HUD 10 according to signals from the light distribution control section 34 .

<Relationship between luminance gradient and visibility>
At night, ambient light such as the light from the headlights of an oncoming vehicle is incident on the driver's pupil, which causes the driver's pupil to become smaller. If the pupil becomes smaller, it becomes difficult for reflected light from the road itself to enter, so the driver's ability to see the road conditions deteriorates, and the visibility of the road conditions in front of the vehicle deteriorates. In particular, when it rains at night, the light from the headlights of oncoming vehicles is likely to be reflected on the road surface and input to the driver, which tends to deteriorate the driver's visual recognition ability.

The inventor of the present application paid attention to the characteristics of the glare illusion (see Non-Patent Document 1) and studied a method of obtaining a mydriatic effect without reducing the amount of light in front of the vehicle V as much as possible. Specifically, the inventors investigated enlarging the driver's pupil by adjusting the luminance gradient of the light contained in the driver's viewing area. The inventors conducted experiments to examine the above assumptions.

7 and 8 show experimental conditions conducted by the inventors of the present application. In FIG. 7, the background of the display D is white and the image displayed on the display D is black, but in reality, the background of the display D is black and white light is displayed on the display D. is doing.

In this experiment, as shown in FIG. 7, an annular area CA was set, and light was displayed on the display D such that the brightness decreased from the outer edge to the inner edge of the annular area CA. The subjects were instructed to gaze at the center P of the toric area CA. Then, the size of the pupil of the subject was measured while changing the ratio of the area where the light was projected (hereinafter referred to as the luminance gradient ratio), the outer edge position of the annular area CA, the width, and the luminance gradient. The luminance gradient ratio was defined as 100% when the light was reflected on the entire annular area CA, and 0% when the light was not displayed at all. The outer edge position of the annular area CA is defined by the angle (i.e., viewing angle) from the point of gaze centering on the pupil of the subject, and the width of the annular area CA is defined by the distance between the outer edge position and the inner edge position of the annular area. Defined by angular difference.

FIG. 8 shows the definition of luminance gradient in this experiment. First, as shown in FIG. 8A, from the outer edge position (position A' in FIG. 8A) to the inner edge position ( The white line luminance is calculated up to the position A in FIG. 8A). Next, as shown in FIG. 8B, a graph is created with the viewing angle on the horizontal axis and the white line luminance on the vertical axis, and the luminance gradient curve is calculated. Then, the average gradient from the outer edge position A' to the inner edge position A is calculated, and the calculated gradient is used as the luminance gradient.

9 to 12 show experimental results, respectively. FIG. 9 shows the relationship between the luminance gradient ratio and the pupil diameter of the subject, FIG. 10 shows the relationship between the outer edge position of the toric area CA and the pupil diameter of the subject, and FIG. The relation with the pupil diameter of the subject is shown, and FIG. 12 shows the relation between the brightness gradient and the pupil diameter of the subject. In each experimental result, parameters other than variables are fixed at arbitrary values.

As shown in FIG. 9, when the luminance gradient ratio was changed, it was found that the mydriatic effect was clearly obtained in the luminance gradient ratio range of 8% to 12%. Specifically, when the luminance gradient ratio is around 10%, the amount of change in pupil diameter becomes maximum. is greater than 10%, the amount of change in pupil diameter decreases as the luminance gradient ratio increases. This is probably because the stimulus to the photoreceptor cells is too small when the luminance gradient ratio is small. On the other hand, when the luminance gradient ratio is large, the amount of light becomes too large and conversely the pupil diameter becomes small. From the results of this experiment, it was found that a mydriatic effect can be easily obtained when the luminance gradient ratio is set to 8% to 12%.

As shown in FIG. 10, it was found that when the outer edge position of the toric area CA was changed, the mydriatic effect was clearly obtained in the range of 10° to 25°. Specifically, when the outer edge position is around 15°, the amount of change in pupil diameter becomes maximum. It was found that the amount of change in pupil diameter is almost constant when the angle is larger than °. This is thought to be related to the density of rod cells responsible for scotopic vision among photoreceptors. Although there are some individual differences, in general, the maximum density of rod cells in the left-right direction is in the region near the viewing angle of 15°. Therefore, it is considered that the maximum mydriatic effect was obtained when the outer edge position of the annular area CA was 15°. From this experimental result, it was found that setting the outer edge position of the annular area CA to 10° to 25° in the radial direction centering on the gaze point of the subject facilitates obtaining the mydriatic effect.

As shown in FIG. 11, it was found that when the width of the annular area CA was changed, the mydriatic effect was clearly obtained in the range of 1° to 4°. Specifically, it becomes maximum when the width is between 2° and 3°, decreases as the width decreases when the width is less than 2°, and decreases as the width increases when the width is greater than 3°. I found out. This is probably because the subject cannot perceive the luminance gradient when the width is small. On the other hand, when the width is large, the amount of light becomes too large and conversely the pupil diameter becomes small. From this experimental result, it was found that setting the width of the annular region CA to 1° to 4° facilitates obtaining the mydriatic effect.

As shown in FIG. 12, when the luminance gradient is changed, the mydriatic effect is clearly obtained in the range of 0.5 (cd/m ² /deg) to 1.5 (cd/m ² /deg). I found out. Specifically, when the luminance gradient is around 1.0 (cd/m ² /deg), the amount of change in pupil diameter becomes maximum, and when the luminance gradient is less than 1.0 (cd/m ² /deg), the luminance gradient approaches 0 (cd/m ² /deg), the amount of change in pupil diameter decreases, and when the luminance gradient is greater than 1.0 (cd/m ² /deg), the amount of pupil diameter change decreases as the luminance gradient increases. found to decrease. This is probably because the perceptible luminance gradient is around 1.0 (cd/m ² /deg) with visual acuity around a viewing angle of 15°. From this experimental result, it was found that a mydriatic effect can be easily obtained when the luminance gradient is set between 0.5 (cd/m ² /deg.) and 1.5 (cd/m ² /deg.).

From the above experimental results, in the first embodiment, the ECU 30 moves from the outer edge position of the annular area to the gaze point FP in the annular area CA within a predetermined angular range in the radial direction centering on the driver's gaze point FP. Each headlight 20 and HUD 10 is controlled so that a predetermined ratio of a predetermined gradient region, which is a predetermined gradient in which the luminance gradient decreases at a specific rate, exists. Specifically, the predetermined angle range is an angle range in which the outer edge position of the annular area CA is 10° to 25° and the width of the annular area CA is 1° to 4°, and the predetermined gradient is 0.5 ( cd/m ² /deg) to 1.5 (cd/m ² /deg), and the predetermined ratio is 8% to 12%. Particularly preferably, the ECU 30 preferably determines that the luminance gradient from the outer edge position to the gaze point FP is 0.5 (cd/m ² /deg) with respect to the annular area CA having an outer edge position of 15° and a width of 2°. Each headlight 20 and HUD 10 is controlled so that a predetermined percentage of a predetermined gradient region in the range of ˜1.5 (cd/m ² /deg) exists.

<Light distribution control in vehicles>
Next, the light distribution control when actually mounted on the vehicle V will be described with reference to FIGS. 13 to 15. FIG.

FIG. 13 shows a case where the vehicle V is traveling straight at night. At this time, the light distribution control unit 34 sends control signals to the headlight control unit 35 to turn on each headlight 20 . The light distribution control unit 34 adjusts the light distribution of the headlights 20 so that the luminance gradient of the light that the headlights 20 irradiate onto the road surface decreases at a predetermined gradient from the near side of the vehicle toward the far side of the vehicle. The predetermined gradient is 0.5 (cd/m ² /deg) to 1.5 (cd/m ² /deg).

In the light distribution control when mounted on the vehicle V, first, the visual field area of the driver is calculated by the visual field area calculator 33 . The field-of-view area calculator 33 synthesizes an image showing the vehicle components within the driver's field of vision when the vehicle V is traveling with the image captured by the front camera 100, and produces an image such as shown in FIGS. 13 and 14 . to generate The field-of-view area calculation unit 33 calculates the line of sight of the driver from the image of the driver captured by the driver monitor camera 102, and calculates the driver's gaze point FP. Next, the field-of-view area calculator 33 sets an annular area CA centered on the point of gaze FP. Here, an annular area CA having an outer edge position of 15° and a width of 2° is set.

Next, the light distribution control unit 34 sets two specific areas SA extending in the circumferential direction of the annular area CA set by the visual field area calculation unit 33 . The specific area SA is set so that the ratio of the entire specific area SA to the entire annular area CA is a predetermined ratio and is evenly distributed to the left and right. Here, the specific area SA is set to 5% on the right side of the center and 5% on the left side of the center so that the ratio of the entire specific area SA to the entire annular area CA is 10%. . Based on the image information synthesized by the visual field calculation unit 33, the light distribution control unit 34 sets each specific area SA to a portion overlapping the area irradiated with the light of the headlights 20 in the annular area CA. Set each. The left and right specific areas SA may be arranged symmetrically or asymmetrically with respect to a straight line passing through the gaze point FA and extending in the vertical direction.

Next, the luminance gradient calculator 31 calculates the luminance gradient in each specific area SA. The brightness gradient calculator 31 calculates the brightness in the radial direction from the outer edge position to the inner edge position of the specific area SA in the same manner as in the experiment described above. The luminance gradient calculator 31 calculates the gradient of the average luminance and uses the calculated gradient as the luminance gradient.

Next, the light distribution control unit 34 determines whether the luminance gradient of each specific area SA is a predetermined gradient, that is, whether each specific area SA is a predetermined gradient area, based on the calculation result of the luminance gradient calculation unit 31. judge. As shown in FIG. 13, on straight roads, obstacles are less likely to exist in the optical path of the headlights 20. Therefore, when the vehicle V is traveling on a straight road, the luminance gradient of the specific area SA is often a predetermined gradient. . The light distribution control unit 34 maintains the current state when each specific area SA is the predetermined gradient area.

FIG. 14 shows a case where the vehicle V is traveling on a left curve at night. Even in this case, the light distribution control unit 34 adjusts the light distribution of the headlights 20 so that the luminance gradient of the light that the headlights 20 irradiate the road surface decreases at a predetermined gradient from the near side of the vehicle to the far side of the vehicle. is doing. The predetermined gradient is 0.5 (cd/m ² /deg) to 1.5 (cd/m ² /deg).

As shown in FIG. 14, in a left curve, there are often obstacles on the optical path of the headlights 20, such as slopes and guardrails, in the front and left area of the vehicle. At this time, the specific area SA on the right tends to have a predetermined luminance gradient, but the specific area SA on the left has a predetermined luminance gradient as a result of the light from the left headlight 20 illuminating the obstacle. Hateful.

When the light distribution control unit 34 determines that the right side specific area SA is a predetermined gradient area but the left side specific area SA is not a predetermined gradient area, the HUD 10 controls the front window glass 1 as viewed from the inside of the vehicle compartment. An image having a predetermined luminance gradient is displayed in the portion overlapping the specific area SA on the left side. The light distribution control unit 34 transmits a control signal for displaying the image in the left specific area SA to the display control unit 36 . The display controller 36 controls the HUD 10 based on the control signal from the light distribution controller 34 . For example, the display control unit 36 displays an image in which the inner edge position of the left specific area SA is darkened so that the luminance gradient of the left specific area SA becomes a predetermined gradient. As a result, both the left and right specific areas SA can be set as predetermined gradient areas. Accordingly, the light distribution control section 34 and the display control section 36 can be an example of a control section.

FIG. 15 is a flowchart showing operation processing of light distribution control by the ECU 30. As shown in FIG.

In step S101, the ECU 30 acquires various sensor information.

Next, in step S102, the ECU 30 determines whether each headlight 20 is on. The ECU 30 determines whether or not an ON signal is being transmitted from the headlight switch 105 . When each headlight 20 is in the ON state (YES), the ECU 30 proceeds to step S103. On the other hand, the ECU 20 returns to step S101 when each headlight 20 is in the off state (NO).

In step S103, the ECU 30 calculates the driver's gaze point FP.

Next, in step S104, the ECU 30 sets an annular area CA within a predetermined angular range in the radial direction centering on the gaze point FP calculated in step S103. The ECU 30 sets an annular area CA having an outer edge position of 10° to 25° and a width of 1° to 4°.

Next, in step S105, the ECU 30 sets a specific area SA for the annular area CA. The ECU 30 is set so that the ratio of the entire specific area SA to the entire annular area CA is a predetermined ratio, and the ratios of the left and right specific areas SA to the entire annular area CA are equal.

Next, in step S106, the ECU 30 calculates the luminance gradient of each specific area SA.

Subsequently, in step S107, the ECU 30 returns when both of the specific areas SA are predetermined gradient areas with a predetermined luminance gradient. On the other hand, the ECU 30 proceeds to step S108 when at least one of the specific areas SA is not the predetermined gradient area and NO.

In step S108, the ECU 30 displays an image having a predetermined luminance gradient in the specific area SA that is not the predetermined gradient area. Specifically, the ECU 30 causes the HUD 10 to display an image in which the brightness gradient of the portion overlaps with the specific region SA, which is not the predetermined gradient region, on the front window glass 1 when viewed from the inside of the vehicle compartment. . After step S108, the process returns.

Therefore, in the first embodiment, the front camera 100 detects the brightness of the road surface illuminated by the headlights 20 of the vehicle V, and the visual field detection unit (front camera 100, driver monitor, The camera 102 and the visual field area calculation unit 33), the brightness gradient calculation unit 31 that calculates the brightness gradient formed by the light of the headlight 20, the light distribution control unit 34 that controls the HUD 10, and the display control unit 36 In addition, the light distribution control unit 34 controls the luminance gradient in the radial direction from the outer edge position to the inner edge position of the annular area CA within a predetermined angular range in the radial direction around the driver's gaze point FP. When the ratio of the predetermined gradient region, which is a predetermined gradient in which is reduced at a specific rate, is less than the predetermined ratio, an image having a predetermined luminance gradient is displayed in a portion of the front window glass 1 that overlaps the annular region CA. A control signal is output to the display control unit 36 so as to do so. As a result, the pupil of the driver can be enlarged by appropriately obtaining a mydriatic effect. As a result, it is possible to improve the visibility of the driver and prevent deterioration of the visibility of the road conditions in front of the vehicle.

In particular, in the first embodiment, the specific area SA extending in the circumferential direction of the annular area CA and having a predetermined proportion of the entire annular area CA is set in advance. The luminance gradient is calculated, and when part of the specific area SA is the predetermined gradient area and the remainder of the specific area SA is not the predetermined gradient area, the light distribution control unit A control signal is output to the display controller 36 so that an image having a predetermined luminance gradient is displayed only in the overlapping portion. Accordingly, since the specific area SA is set in advance, the predetermined gradient area can be formed in the annular area CA in an appropriate ratio. As a result, the driver's visual recognition ability can be improved more effectively.

In addition, in the first embodiment, the specific area SA is set to the left and right at an equal ratio. The left and right pupils of the driver can be appropriately stimulated, and the mydriatic effect can be properly obtained for both the left and right pupils. As a result, the driver's visual recognition ability can be improved more effectively.

Further, in the first embodiment, the visual field calculation unit 33 detects the visual field area of the driver based on the input signals from the driver monitor camera 102 that captures the driver and the front camera 100 that captures the front of the vehicle V. As a result, the point of gaze FP of the driver can be detected with high accuracy, and as a result, the annular area CA in which the mydriatic effect can be obtained can be set with high accuracy. As a result, the driver's visual recognition ability can be improved more effectively.

<Embodiment 2>
Hereinafter, Embodiment 2 will be described in detail with reference to the drawings. In the following description, the same reference numerals are assigned to the same parts as in the first embodiment, and detailed description thereof will be omitted.

The second embodiment differs from the first embodiment in light distribution control by the light distribution control unit 34 . Light distribution control in the second embodiment will be described with reference to FIGS. 16 and 17. FIG.

FIG. 16 shows a case where the vehicle V is traveling on a left curve at night. The light distribution control unit 34 adjusts the light distribution of the headlights 20 so that the luminance gradient of the light that the headlights 20 irradiate onto the road surface decreases at a predetermined gradient from the near side of the vehicle toward the far side of the vehicle. The predetermined gradient is 0.5 (cd/m ² /deg) to 1.5 (cd/m ² /deg).

In Embodiment 2, the light distribution control unit 34 does not set the specific area SA. In the second embodiment, the luminance gradient calculator 31 calculates the luminance gradient of the entire annular area CA after the light distribution controller 34 sets the annular area CA. Note that the brightness gradient calculation unit 31 calculates the brightness of a portion of the annular area CA that overlaps the front window glass 1 (strictly speaking, the portion that overlaps with the front window glass of the synthesized image generated by the viewing area calculation unit 33). Alternatively, only the gradient may be calculated.

Next, the light distribution control unit 34 identifies a predetermined gradient area existing in the annular area CA from the calculation result of the luminance gradient calculation unit 31 . Here, as shown in FIG. 16, it is assumed that the predetermined gradient area is identified only in the right portion of the annular area CA. This predetermined gradient area is a predetermined gradient area formed by the light of the headlights 20 .

Next, the light distribution control unit 34 calculates the ratio of the predetermined gradient area formed by the light from the headlights 20 to the entire annular area. Here, it is assumed that the predetermined gradient area formed by the light of the headlights 20 is 3% of the total toric area.

Then, the light distribution control unit 34 controls the portion of the front window glass 1 that overlaps the annular area CA as viewed from the inside of the vehicle so that the ratio of the predetermined gradient area to the entire annular area becomes a predetermined ratio. Then, an image is displayed in which the luminance gradient of the relevant portion is a predetermined gradient. More specifically, for example, when the predetermined ratio is 10%, the predetermined gradient area formed by the light from the headlights 20 is already 3%, so the light distribution control unit An image having a predetermined luminance gradient is displayed in an area corresponding to 7% of the direction (indicated by hatching in FIG. 16). The light distribution control section 34 transmits a control signal for displaying the image to the display control section 36 . The display controller 36 controls the HUD 10 based on the control signal from the light distribution controller 34 . As a result, the ratio of the predetermined gradient area to the annular area CA becomes the predetermined ratio.

The light distribution control unit 34 transmits a control signal to the display control unit 36 so as to display the image in the lowest possible portion of the annular area CA. This is because displaying an image at a position similar to that of the road surface in the driver's field of view is less likely to affect the driving of the driver.

FIG. 17 is a flowchart showing operation processing of light distribution control by the ECU 30 in the second embodiment.

In step S201, the ECU 30 acquires various sensor information.

Next, in step S202, the ECU 30 determines whether each headlight 20 is on. The ECU 30 determines whether or not an ON signal is being transmitted from the headlight switch 105 . When each headlight 20 is in the ON state (YES), the ECU 30 proceeds to step S203. On the other hand, the ECU 20 returns to step S201 when each headlight 20 is in the OFF state (NO).

In step S203, the ECU 30 calculates the driver's gaze point FP.

Next, in step S204, the ECU 30 sets an annular area CA within a predetermined angular range in the radial direction centering on the gaze point FP calculated in step S203. The ECU 30 sets an annular area CA having an outer edge position of 10° to 25° and a width of 1° to 4°.

Next, in step S205, the ECU 30 calculates the brightness gradient of the annular area CA.

Subsequently, in step S206, the ECU 30 determines whether or not a predetermined proportion of the predetermined slope area exists in the annular area CA. The ECU 30 returns when YES indicating that a predetermined proportion of the predetermined gradient area exists in the annular area CA. On the other hand, the ECU 30 advances to step S207 when the predetermined gradient area does not exist at the predetermined ratio in the annular area CA (NO).

In step S207, the ECU 30 displays an image having a predetermined luminance gradient such that a predetermined ratio of the predetermined gradient area exists in the annular area CA. Specifically, the ECU 30 causes the HUD 10 to display an image having a predetermined luminance gradient on a portion of the front window glass 1 that overlaps the annular region CA as viewed from the inside of the vehicle. The ECU 30 calculates the ratio of the predetermined gradient area formed by the headlights 20 to the entire annular area CA, and displays the image only in the area corresponding to the ratio obtained by subtracting the calculated ratio from the predetermined ratio. After step S207, the process returns.

Therefore, in the second embodiment, the light distribution control unit 34 controls the distribution of light from the outer edge position to the inner edge position of the annular area CA within a predetermined angular range in the radial direction centering on the driver's gaze point FP. When the ratio of the predetermined gradient region, which is a predetermined gradient in which the luminance gradient in the radial direction decreases at a specific rate, is less than the predetermined ratio, the front surface is adjusted so that the ratio of the predetermined gradient region in the annular area CA is the predetermined ratio. A control signal is output to the display controller 36 so that an image having a predetermined luminance gradient is displayed on the portion of the window glass 1 that overlaps the annular region CA. As a result, the pupil of the driver can be enlarged by appropriately obtaining a mydriatic effect. As a result, it is possible to improve the visibility of the driver and prevent deterioration of the visibility of the road conditions in front of the vehicle.

<Embodiment 3>
Hereinafter, Embodiment 3 will be described in detail with reference to the drawings. In the following description, the parts common to those of the first and second embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the third embodiment, the light distribution control process of the ECU 30 is different from the above-described first and second embodiments. Specifically, in the third embodiment, the ECU 30 causes the HUD 10 to display an image with a predetermined luminance gradient only when there is an obstacle on the optical path of the headlight 20 . When there is no obstacle on the optical path of the headlight 20, the ECU 30 controls the headlight 20 so that the predetermined ratio of the predetermined gradient area exists within the annular area CA.

FIG. 18 is a flow chart showing operation processing of light distribution control by the ECU 30 in the third embodiment.

In step S301, the ECU 30 acquires various sensor information.

Next, in step S302, the ECU 30 determines whether each headlight 20 is on. The ECU 30 determines whether or not an ON signal is being transmitted from the headlight switch 105 . When the determination is YES that each headlight 20 is on, the ECU 30 proceeds to step S303. On the other hand, the ECU 20 returns to step S301 when each headlight 20 is in the off state (NO).

In step S303, the ECU 30 calculates the driver's gaze point FP.

Next, in step S304, the ECU 30 sets an annular area CA within a predetermined angular range in the radial direction centering on the gaze point FP calculated in step S303. The ECU 30 sets an annular area CA having an outer edge position of 10° to 25° and a width of 1° to 4°.

Next, in step S305, the ECU 30 calculates the luminance gradient of the annular area CA.

Subsequently, in step S306, the ECU 30 determines whether or not a predetermined proportion of the predetermined slope area exists in the annular area CA. The ECU 30 returns when YES indicating that a predetermined proportion of the predetermined gradient area exists in the annular area CA. On the other hand, the ECU 30 proceeds to step S307 when NO, that is, the predetermined ratio of the predetermined slope area does not exist in the annular area CA.

In step S307, the ECU 30 detects the shape of the road on which the vehicle V is traveling. The road shape detected here includes not only the shape of the road, but also targets on the road, slopes of mountains on the left and right sides of the road, forests, guardrails, utility poles, and the like.

In the next step S<b>308 , the ECU 30 determines whether or not there is an obstacle on the optical path of the headlight 20 . This obstacle is an obstacle that blocks the light from the headlights 20 . When the determination is YES that there is an obstacle on the optical path of the headlight 20, the ECU 30 proceeds to step S309. On the other hand, the ECU 30 proceeds to step S310 when there is no obstacle on the optical path of the headlight 20 (NO).

In step S309, the ECU 30 displays an image having a predetermined luminance gradient such that a predetermined ratio of the predetermined gradient area exists in the annular area CA. Specifically, the ECU 30 causes the HUD 10 to display an image having a predetermined luminance gradient on a portion of the front window glass 1 that overlaps the annular region CA as viewed from the inside of the vehicle. The ECU 30 calculates the ratio of the predetermined gradient area formed by the headlights 20 to the entire annular area CA, and displays the image only in the area corresponding to the ratio obtained by subtracting the calculated ratio from the predetermined ratio. After step S309, the process returns.

On the other hand, in step S309, the ECU 30 adjusts the light distribution of the headlights 20 so that the annular area CA has a predetermined gradient area at a predetermined ratio. After step S310, the process returns.

In the third embodiment, the light distribution control unit 34 radiates from the outer edge position to the inner edge position of the annular area CA within a predetermined angle range in the radial direction centering on the point of gaze FP of the driver. A portion of the front window glass 1 that overlaps the annular region CA has a predetermined luminance gradient so that the ratio of the predetermined gradient region, which is a predetermined gradient that decreases at a specific rate, becomes a predetermined ratio. A control signal is output to the display control unit 36 or a control signal is output to the headlight control unit 35 so as to display an image. As a result, the pupil of the driver can be enlarged by appropriately obtaining a mydriatic effect. As a result, it is possible to improve the visibility of the driver and prevent deterioration of the visibility of the road conditions in front of the vehicle.

(Other embodiments)
The technology disclosed herein is not limited to the above-described embodiments, and substitutions are possible without departing from the scope of the claims.

In the first embodiment described above, the specific areas SA are set evenly on the left and right, but the sizes of the specific areas on the left and right may be different. In particular, the sizes of the left and right specific regions may be adjusted according to the shape of the road.

Further, in the first embodiment described above, an image having a predetermined luminance gradient is displayed only in a specific region having a non-predetermined luminance gradient. Without being limited to this, when there is a specific region where the luminance gradient is not the predetermined gradient, the image may be displayed in all of the specific regions.

Further, by combining the above-described first and third embodiments, for example, when the specific area SA and an obstacle on the optical path of the headlight 20 overlap, the specific area SA has a predetermined luminance gradient. HUD 10 may be controlled to display an image.

Further, in the first to third embodiments described above, the light distribution control by the ECU 30 may be performed only at night when it rains. Whether it is raining or not can be determined based on signals from the rain sensor 103 and the wiper switch 104 .

The above-described embodiments are merely examples, and should not be construed as limiting the scope of the present disclosure. The scope of the present disclosure is defined by the claims, and all modifications and changes within the equivalent range of the claims are within the scope of the present disclosure.

The technology disclosed herein is useful as a vehicle lighting control device having a display that is positioned in front of the driver and displays a virtual image.

1 Front window glass (display)
10 Head-up display (display)
20 headlight 30 ECU (control unit)
31 luminance gradient calculator 33 visual field calculator (visual field detector)
34 light distribution control unit (control unit)
36 Display control unit (control unit)
100 Front camera (road surface luminance detector, visual field detection unit)
102 Driver monitor camera (viewing area detection unit)
CA Annular area SA Specific area FP Point of regard V Vehicle

Claims (8)

A vehicle lighting control device having a display positioned in front of a driver and displaying a virtual image,
a road surface brightness detector that detects the brightness of the road surface illuminated by the headlights of the vehicle;
A visual field detection unit that detects a visual field area of a driver of the vehicle;
a luminance gradient calculation unit that calculates a luminance gradient formed by the light of the headlight;
A control unit that controls the display,
The control unit reduces a luminance gradient in a radial direction from an outer edge position to an inner edge position of the annular area within a predetermined angular range in the radial direction centering on the gaze point of the driver at a specific rate. when the ratio of the predetermined gradient region, which is the predetermined gradient, is less than the predetermined ratio, an image having the predetermined luminance gradient is displayed in a portion of the display that overlaps with the annular region. lighting controller. In the vehicle lighting control device according to claim 1,
The control unit displays an image having a luminance gradient of the predetermined gradient in a portion of the display that overlaps the annular region so that the ratio of the predetermined gradient region in the annular region is the predetermined ratio. A lighting control device for a vehicle, characterized by: In the vehicle lighting control device according to claim 1 or 2,
A lighting control device for a vehicle, wherein the visual field area detection unit detects the visual field area based on input signals from a driver monitor camera that captures an image of the driver and a front camera that captures an image in front of the vehicle. In the vehicle lighting control device according to any one of claims 1 to 3,
A lighting control device for a vehicle, wherein an outer edge position of the annular region is set between 10° and 25° in a radial direction centering on the gaze point of the driver. In the vehicle lighting control device according to any one of claims 1 to 4,
A lighting control device for a vehicle, wherein the width of the predetermined angle range is set to 1° to 4°. In the vehicle lighting control device according to any one of claims 1 to 5,
The lighting control device for a vehicle, wherein the predetermined ratio is set to 8% to 12%. In the vehicle lighting control device according to any one of claims 1 to 6,
The brightness gradient calculation unit calculates a brightness gradient of a specific region that extends in the circumferential direction of the annular region and is set by the predetermined proportion of the entire annular region,
When a portion of the specific region is the predetermined gradient region and the remainder of the specific region is not the predetermined gradient region, the control unit controls that only a portion of the display that overlaps the remainder of the specific region has a luminance gradient. A lighting control device for a vehicle, characterized by displaying an image having the predetermined gradient. In the vehicle lighting control device according to claim 7,
A lighting control device for a vehicle, wherein the specific areas are set in equal proportions to the left and right.

Images