Light distribution control device
The light distribution control device adjusts headlight illuminance based on both lateral position and speed of a vehicle ahead, addressing inaccuracies in existing systems by ensuring precise and adaptive low-illuminance area settings.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2023-11-17
- Publication Date
- 2026-07-22
Smart Images
Figure 0007893224000001 
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Abstract
Description
Technical Field
[0001] The present disclosure relates to a light distribution control device.
Background Art
[0002] Conventionally, as a light distribution control device that controls light distribution so that the illuminance of a first area including a vehicle ahead of a vehicle is lower than the illuminance of a second area not including the vehicle ahead, based on a forward imaging image of an in-vehicle camera of the vehicle, for example, the device described in Patent Document 1 is known.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In a light distribution control device that controls the light distribution of a headlight, based on the lateral position of a vehicle ahead in a forward imaging image of an in-vehicle camera of the vehicle, the range of a first area having an illuminance lower than the illuminance of a second area not including the vehicle ahead is set. Here, if the range of the first area is set only based on the lateral position of the vehicle ahead in the forward imaging image, for example, when a delay occurs in the processing of the control unit, the vehicle ahead moving laterally in the forward imaging image may protrude from the range of the first area. On the other hand, if the range of the first area is expanded in advance considering the movement of the vehicle ahead, the range of the first area may become too wide when the vehicle ahead is not moving laterally in the forward imaging image.
Means for Solving the Problems
[0005] One aspect of the present disclosure is a light distribution control device for controlling the light distribution of a headlight that illuminates the area in front of a vehicle, comprising a control unit that controls the light distribution based on a forward-imported image of an on-board camera of the vehicle so that the illuminance of a first area including a vehicle in front of the vehicle is less than the illuminance of a second area not including a vehicle in front, wherein the control unit sets the range of the first area based on the lateral position of the vehicle in front in the forward-imported image and the lateral movement speed of the vehicle in front in the forward-imported image.
[0006] In a light distribution control device according to one aspect of this disclosure, the control unit sets the range of the first region based not only on the lateral position of the vehicle in front in the forward-imaging image, but also on the speed at which the vehicle in front moves laterally in the forward-imaging image. As a result, because the range of the first region is set based not only on the lateral position of the vehicle in front in the forward-imaging image but also on its speed, the range of the first region can be set in such a way that it suppresses the overhang of the vehicle in front that is moving laterally in the forward-imaging image, for example, when there is a delay in the processing of the control unit. As a result, it is possible to prevent the range of the first region from becoming too wide when the vehicle in front is not moving laterally in the forward-imaging image, by not expanding the range of the first region too much in advance.Therefore, according to a light distribution control device according to one aspect of this disclosure, when the vehicle in front is moving laterally in the forward-imaging image, the range of the first region can be set more appropriately than when it is based only on the lateral position of the vehicle in front in the forward-imaging image.
[0007] In one embodiment, the control unit may acquire a right margin to expand the first region to the right relative to the right edge position based on the right edge position of the forward vehicle region surrounding the forward vehicle in the forward image, and acquire a left margin to expand the first region to the left relative to the left edge position based on the left edge position of the forward vehicle region in the forward image. If the movement speed is greater than or equal to a predetermined value in the right direction, the control unit may increase the right margin and decrease the left margin compared to the case where the movement speed is not greater than or equal to a predetermined value in the right direction, and if the movement speed is greater than or equal to a predetermined value in the left direction, the control unit may increase the left margin and decrease the right margin compared to the case where the movement speed is not greater than or equal to a predetermined value in the left direction. In this case, the range of the first region can be corrected laterally to match the forward vehicle moving laterally in the forward image. [Effects of the Invention]
[0008] According to one aspect of the present disclosure, when the vehicle in front is moving laterally in the forward-imaging image, the range of the first region can be set more appropriately than when it is based solely on the lateral position of the vehicle in front in the forward-imaging image. [Brief explanation of the drawing]
[0009] [Figure 1] Block diagram showing a light distribution control device according to one embodiment. [Figure 2] This diagram illustrates the angles of each vehicle in the forward-facing image. [Figure 3] (a) is a graph of the right margin coefficient. (b) is a graph of the left margin coefficient. (c) is a graph of the upper margin coefficient. (d) is a graph of the lower margin coefficient. [Figure 4] (a) is a graph of the offset right margin coefficient. (b) is a graph of the offset left margin coefficient. [Figure 5] Figure 2 illustrates the extent of the first region of the vehicle in front. [Figure 6](a) is a diagram showing the range of the first region in a comparative example for a forward vehicle moving laterally. (b) is a diagram showing the range of the first region in a comparative example when the forward vehicle in Figure 6(a) moves further laterally. [Figure 7] (a) is a diagram showing the extent of the first region according to another comparative example when the vehicle in front of Figure 6(a) moves further laterally. (b) is a diagram showing the extent of the first region according to the embodiment when the vehicle in front of Figure 6(a) moves further laterally. [Figure 8] Figure 1 is a flowchart showing an example of the processing performed by the light distribution control ECU. [Figure 9] Figure 8 is a flowchart showing an example of the calculation process for the margin coefficient. [Modes for carrying out the invention]
[0010] The embodiments of this disclosure will be described below with reference to the drawings.
[0011] Figure 1 is a block diagram showing a light distribution control device according to one embodiment. The light distribution control device 100 is mounted on a vehicle such as a passenger car. The light distribution control device 100 is a device for controlling the light distribution of the headlights that illuminate the area in front of the vehicle. Some functions of the light distribution control device 100 may be executed on a server that can communicate with the vehicle. In this embodiment, the oncoming lane in which the oncoming vehicle (vehicle in front) is traveling is located to the right of the lane in which the vehicle is traveling.
[0012] [Configuration of the light distribution control device] The configuration of the light distribution control device 100 according to this embodiment will be described below with reference to Figure 1. As shown in Figure 1, the light distribution control device 100 includes a light distribution control ECU (Electronic Control Unit) 10, an external sensor 20, an internal sensor 21, and a headlight 30. The external sensor 20, the internal sensor 21, and the headlight 30 are connected to the light distribution control ECU 10.
[0013] The light distribution control ECU 10 is an electronic control unit having a CPU (Central Processing Unit), a memory unit, and an interface (I / F). The memory unit consists of, for example, ROM (Read Only Memory), RAM (Random Access Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), etc. The light distribution control ECU 10 realizes various functions by, for example, executing a program stored in the memory unit with the CPU. The light distribution control ECU 10 may be composed of multiple electronic units.
[0014] The external sensor 20 is a detection device that detects the conditions around the vehicle. The external sensor 20 includes a camera (onboard camera). The external sensor 20 may also include a radar sensor. The camera is an imaging device that captures images of the conditions in front of the vehicle. The camera is installed, for example, on the back of the rearview mirror behind the windshield of the vehicle and captures images of the area in front of the vehicle. The optical axis of the camera coincides with the longitudinal axis of the vehicle in a plan view of the vehicle. Here, the longitudinal axis is an axis that passes through the center of the vehicle in the width direction and is parallel to the ground surface of the vehicle. The camera transmits the forward-captured images of the conditions in front of the vehicle to the light distribution control ECU 10.
[0015] A radar sensor is a detection device that uses radio waves (e.g., millimeter waves) or light to detect objects around a vehicle. Objects around a vehicle include other vehicles traveling in front of the vehicle. The radar sensor may include, for example, millimeter-wave radar or LiDAR (Light Detection and Ranging). The radar sensor transmits information about the detected object to the light distribution control ECU 10.
[0016] The internal sensor 21 is a detection device that detects the driving state of the vehicle. The internal sensor 21 includes a vehicle speed sensor. The vehicle speed sensor is a detector that detects the speed of the vehicle. As the vehicle speed sensor, for example, a wheel speed sensor that detects the rotational speed of a wheel of the vehicle or a drive shaft that rotates integrally with the wheel is used. The internal sensor 21 may include an acceleration sensor and a yaw rate sensor.
[0017] The headlight 30 includes, for example, a left headlight provided at the left front end of the vehicle and a right headlight provided at the right front end of the vehicle. The left headlight and the right headlight are headlamps for driving having a high beam function. The left headlight and the right headlight may have a low beam function. The headlight 30 is a light using an LED matrix as a light source. The LED matrix includes an LED group composed of a plurality of LEDs. The LED group is two-dimensionally arranged at a predetermined interval in the horizontal and vertical directions when viewed from the front of the vehicle. The light distribution control ECU 10 independently controls the lighting or extinguishing of the LED groups of the left and right headlights for each LED. The light distribution control ECU 10 independently controls the current value supplied to the LED groups of the left and right headlights for each LED. When the LED group is controlled to light by the light distribution control ECU 10, the LED group emits light and irradiates the front area of the vehicle.
[0018] The light distribution control ECU 10 recognizes the driving state of the vehicle based on the detection result of the internal sensor 21. The driving state includes the vehicle speed of the vehicle. The driving state may include the acceleration of the vehicle and the yaw rate of the vehicle. The light distribution control ECU 10 recognizes the vehicle speed of the vehicle based on the vehicle speed information of the vehicle speed sensor. The light distribution control ECU 10 may recognize the acceleration of the vehicle based on the acceleration information of the acceleration sensor. The light distribution control ECU 10 may recognize the direction of the vehicle based on the yaw rate information of the yaw rate sensor.
[0019] The light distribution control ECU 10 recognizes the situation in front of the vehicle based on the detection results of the external sensor 20. The situation in front includes the driving state of the vehicle in front. The driving state of the vehicle in front includes the relative position, relative speed, and direction of movement of the vehicle in front relative to the vehicle. The driving state of the vehicle in front may also include the relative angular velocity and relative angular acceleration of the vehicle in front. Relative angular velocity is the relative angular velocity of the vehicle in front as seen from the vehicle.
[0020] The light distribution control ECU 10 detects light sources based on the forward-facing image. Light sources include ambient light and light from other vehicles. Ambient light is light from streetlights and buildings, etc. Light from other vehicles is light from vehicles ahead, such as the headlights of oncoming vehicles and the taillights of preceding vehicles. Vehicles ahead may include not only vehicles in the oncoming lane but also vehicles traveling at intersections in a direction intersecting the vehicle's direction of travel. The light distribution control ECU 10 recognizes the type of detected light source (ambient light or light from other vehicles) using a well-known method.
[0021] The light distribution control ECU 10 is capable of performing adaptive high-beam control. Adaptive high-beam control is a control that controls the light distribution (high-beam light distribution) of the headlight 30 so that the illuminance in a first region including the vehicle in front of the vehicle is less than the illuminance in a second region that does not include the vehicle in front. The first region is a so-called "dimmed region" or "shaded region".
[0022] Figure 2 is a diagram illustrating the angles of each vehicle in the forward-facing image. Figure 2 shows the forward-facing image IM when the headlights 130, which are the light source of the oncoming vehicle (forward vehicle) V, are captured by the camera. In reality, the body of the oncoming vehicle V may not be clearly captured, but for the sake of explanation, the body of the oncoming vehicle V is shown in Figure 2.
[0023] As an example, the light distribution control ECU 10 calculates the vehicle angle of the vehicle in front based on the forward-facing image. The vehicle angle of the vehicle in front is a relative angle with respect to a predetermined direction, representing the position of the vehicle in front as seen from the vehicle. As shown in Figure 2, the vehicle angle includes the right vehicle angle θr, the left vehicle angle θL, the center vehicle angle θm, the upper vehicle angle θu, and the lower vehicle angle θd. The right vehicle angle θr is the lateral angle (lateral angle) of the right end of the vehicle in front relative to the longitudinal axis of the vehicle. The left vehicle angle θL is the lateral angle of the left end of the vehicle in front relative to the longitudinal axis. The center vehicle angle θm is the lateral angle of the center of the vehicle in front relative to the longitudinal axis. The upper vehicle angle θu is the vertical angle (vertical angle) of the upper end of the vehicle in front relative to the longitudinal axis. The lower vehicle angle θd is the vertical angle of the lower end of the vehicle in front relative to the longitudinal axis.
[0024] The light distribution control ECU 10 estimates the forward vehicle region F, which is the area surrounding the forward vehicle, based on the light source of the forward vehicle detected from the forward image IM. The forward vehicle region F may be rectangular in shape, for example, and consist of a pair of sides extending horizontally and a pair of sides extending vertically. In the following description, the horizontal position of any point in the forward image IM is referred to as the "horizontal position," and the vertical position of the same point is referred to as the "vertical position."
[0025] The light distribution control ECU 10 calculates, for example, the horizontal position Pr of the right edge of the front vehicle area F, the horizontal position PL of the left edge of the front vehicle area F, the horizontal position Pm of the center M of the front vehicle area F, the vertical position Pu of the upper edge of the front vehicle area F, and the vertical position Pd of the lower edge of the front vehicle area F. The horizontal positions Pr, PL, and Pm are calculated, for example, as the horizontal length (number of pixels) from the horizontal position PfoeL of the vanishing point FOE [Focus Of Expansion] of the forward image IM. The vertical positions Pu and Pd are calculated, for example, as the vertical length (number of pixels) from the vertical position PfoeV of the vanishing point FOE.
[0026] The light distribution control ECU 10 calculates the right vehicle angle θr, left vehicle angle θL, center vehicle angle θm, upper vehicle angle θu, and lower vehicle angle θd by converting the horizontal position Pr, horizontal position PL, horizontal position Pm, vertical position Pu, and vertical position Pd into angles.
[0027] The lateral length LL of the forward-facing image IM corresponds to the camera's horizontal field of view. The camera's optical axis passes through, for example, the center of the vehicle in the vehicle width direction (lateral direction). The angle (lateral angle with respect to the longitudinal axis) corresponding to the lateral position PfoeL of the vanishing point FOE is 0°. In this case, the right vehicle angle θr of the oncoming vehicle V can be calculated by proportionally allocating the camera's horizontal field of view using the ratio of the lateral position Pr to the lateral length LL of the forward-facing image IM. The left vehicle angle θL of the oncoming vehicle V can be calculated by proportionally allocating the camera's horizontal field of view using the ratio of the lateral position PL to the lateral length LL. The center vehicle angle θm of the oncoming vehicle V can be calculated by proportionally allocating the camera's horizontal field of view using the ratio of the lateral position Pm to the lateral length LL.
[0028] The vertical length LV of the forward-imaging image IM corresponds to the vertical field of view of the camera. The optical axis of the camera is oriented such that, for example, the vanishing point FOE is located in the vertical center of the forward-imaging image IM. The angle (vertical angle with respect to the front-rear axis) corresponding to the vertical position PfoeV of the vanishing point FOE is 0°. In this case, the upper vehicle angle θu of the oncoming vehicle V can be calculated by proportionally allocating the camera's vertical field of view using the ratio of the vertical position Pu to the vertical length LV of the forward-imaging image IM. The lower vehicle angle θd of the oncoming vehicle V can be calculated by proportionally allocating the vertical field of view using the ratio of the vertical position Pd to the vertical length LV.
[0029] The light distribution control ECU 10 calculates the right vehicle width angle Δθr and the left vehicle width angle ΔθL from the vehicle width angle of the vehicle in front. The vehicle width angle of the vehicle in front is an angle that represents the range of the vehicle width of the vehicle in front as seen from the vehicle. The vehicle width angle can be calculated as the difference between the right vehicle angle θr and the left vehicle angle θL. The vehicle width angle corresponds to the horizontal length of the vehicle in front (forward vehicle region F) in the forward image IM. The light distribution control ECU 10 calculates the right vehicle width angle Δθr and the left vehicle width angle ΔθL as, for example, half the value of the vehicle width angle. The right vehicle width angle Δθr corresponds to the horizontal length from the center M of the vehicle in front to the right edge of the forward vehicle region F. The left vehicle width angle ΔθL corresponds to the horizontal length from the center M of the vehicle in front to the left edge of the forward vehicle region F.
[0030] The light distribution control ECU 10 calculates the upper vehicle height angle Δθu and the lower vehicle height angle Δθd from the vehicle height angle of the vehicle in front. The vehicle height angle of the vehicle in front is an angle that represents the range of the vehicle height of the vehicle in front as seen from the vehicle. The vehicle height angle can be calculated as the difference between the upper vehicle angle θu and the lower vehicle angle θd. The vehicle height angle corresponds to the vertical length of the vehicle in front (forward vehicle region F) in the forward image IM. The light distribution control ECU 10 calculates the upper vehicle height angle Δθu and the lower vehicle height angle Δθd as, for example, half the value of the vehicle height angle. The upper vehicle height angle Δθu corresponds to the vertical length from the center M of the vehicle in front to the upper end of the forward vehicle region F. The lower vehicle height angle Δθd corresponds to the vertical length from the center M of the vehicle in front to the lower end of the forward vehicle region F.
[0031] The light distribution control ECU 10 sets the range of the first region based on the lateral position of the vehicle in front in the forward-imaging image and the lateral movement speed of the vehicle in front in the forward-imaging image. As an example, the light distribution control ECU 10 determines margin coefficients to define the range of the first region R1. The margin coefficients include a right margin coefficient Cr, a left margin coefficient CL, an upper margin coefficient Cu, and a lower margin coefficient Cd. The right margin coefficient Cr is a coefficient for obtaining a right margin to extend the first region to the right relative to the right edge position, based on the right edge position of the forward vehicle region surrounding the vehicle in front in the forward-imaging image. The left margin coefficient CL is a coefficient for obtaining a left margin to extend the first region to the left relative to the left edge position, based on the left edge position of the forward vehicle region in the forward-imaging image.
[0032] Figure 3(a) is a graph of the right margin coefficient. Figure 3(b) is a graph of the left margin coefficient. Figure 3(c) is a graph of the upper margin coefficient. Figure 3(d) is a graph of the lower margin coefficient. In the graphs of Figures 3(a) to 3(d), the light distribution control ECU 10 acquires each margin coefficient based on the right and left edge positions of the forward vehicle region of the vehicle in front in the forward image. The right margin coefficient C1r is determined by reading the margin coefficient corresponding to the right vehicle angle θ1r in the graph of Figure 3(a) when the right vehicle angle θr corresponding to the right edge position of the forward vehicle region F is the right vehicle angle θ1r. The left margin coefficient C1L is determined by reading the margin coefficient corresponding to the left vehicle angle θ1L in the graph of Figure 3(b) when the left vehicle angle θL corresponding to the left edge position of the forward vehicle region F is the left vehicle angle θ1L. The upper margin coefficient C1u and the lower margin coefficient C1d are determined by reading the margin coefficients corresponding to the central vehicle angle θ1m in the graphs of Figure 3(c) and Figure 3(d), when the central vehicle angle θm of the forward vehicle region F is θ1m. The minimum values of each margin coefficient C1r, C1L, C1u, and C1d are all 1 or greater.
[0033] The light distribution control ECU 10 corrects the right margin coefficient and the left margin coefficient based on the lateral movement speed of the vehicle in front in the forward-captured image, for example. As an example, the light distribution control ECU 10 here acquires an offset amount based on the lateral movement speed of the vehicle in front in the forward-captured image, and uses the offset amount to correct the right margin coefficient and the left margin coefficient.
[0034] The light distribution control ECU 10, for example, if the magnitude of the moving speed is not greater than or equal to a predetermined value, acquires the right margin coefficient and left margin coefficient obtained from the graphs in Figures 3(a) and 3(b) as the basic margin coefficient. The basic margin coefficient is the margin coefficient before correction. The moving speed can be, for example, the relative angular velocity of the vehicle in front. The relative angular velocity may be calculated as the rate of change in angle based on the time change of the lateral position of the vehicle in front in the forward-imaging image. The predetermined value is a threshold value for the moving speed to switch whether or not to correct the right margin coefficient and left margin coefficient. The predetermined value may be set in advance, for example, according to the processing speed of the light distribution control ECU 10.
[0035] The light distribution control ECU 10 may, for example, increase the right margin coefficient Cr when the moving speed in the right direction is greater than or equal to a predetermined value, compared to when the moving speed in the right direction is not greater than or equal to a predetermined value. The light distribution control ECU 10 may also, for example, decrease the left margin coefficient CL when the moving speed in the right direction is greater than or equal to a predetermined value, compared to when the moving speed in the right direction is not greater than or equal to a predetermined value.
[0036] Specifically, Figure 4(a) shows a graph of the offset right margin coefficient. Figure 4(b) shows a graph of the offset left margin coefficient. As shown in Figures 4(a) and 4(b), the offset amount refers to the amount of movement that offsets (translates) the curves of the right margin coefficient and the left margin coefficient in the vertical axis direction of the margin coefficient graph. It can also be said that the light distribution control ECU 10 interprets the graphs in Figures 4(a) and 4(b) as values shifted in the vertical axis direction by the offset amount compared to the graphs in Figures 3(a) and 3(b). The offset amount may be a parameter or a variable value. The magnitude of the offset amount is, for example, set to a larger value the greater the relative angular velocity of the vehicle in front. The magnitude of the offset amount may also be adjusted according to the relative angular acceleration of the vehicle in front.
[0037] The graphs in Figures 4(a) and 4(b) correspond to the case where the speed of movement is greater than or equal to a predetermined value in the rightward direction. As shown in Figure 4(a), the right margin coefficient C2r is determined by reading the right margin coefficient C2r, which is obtained by increasing the dashed right margin coefficient (basic margin coefficient) corresponding to the graph in Figure 3(a) by an offset amount, at the right vehicle angle θ2r corresponding to the right edge position of the forward vehicle area surrounding the vehicle in front.
[0038] As shown in Figure 4(b), the left margin coefficient C2L is determined by reading the dashed left margin coefficient (basic margin coefficient) corresponding to the graph in Figure 3(b) at the position corresponding to the left vehicle angle θ2L that corresponds to the left edge position of the forward vehicle area surrounding the vehicle in front, and reducing it by the offset amount. The left margin coefficient C2L is determined so that it is not smaller than the guard value C2g. The value of the guard value C2g is, for example, 1.
[0039] The light distribution control ECU 10 defines (sets) a first region including the vehicle in front of the vehicle. Figure 5 is an example diagram illustrating the range of the first region of the vehicle in front of Figure 2. As shown in Figure 5, the range of the first region R1 is defined, for example, by the lateral and vertical shading angles corresponding to the range of the first region R1. The lateral shading angle is a lateral angle that represents the range in the lateral direction that reduces the illuminance of the headlights as seen from the vehicle. The vertical shading angle is a vertical angle that represents the range in the vertical direction that reduces the illuminance of the headlights as seen from the vehicle. In the example in Figure 5, the range of the first region R1 is defined by the positions corresponding to the lateral shading angles θrt and θLt and the vertical shading angles θut and θdt.
[0040] The light distribution control ECU 10 calculates, for example, a target shading angle corresponding to the range of the first region R1 in order to determine the horizontal shading angles θrt and θLt and the vertical shading angles θut and θdt. The target shading angle is an angle range that represents the range in which the illuminance of the headlights is reduced as viewed from the vehicle. The target shading angle includes the right target shading angle Δθrt, the left target shading angle ΔθLt, the upper target shading angle Δθut, and the lower target shading angle Δθdt.
[0041] The right target shading angle Δθrt corresponds to the horizontal length from the center M of the vehicle ahead to the right edge of the first region R1. The right target shading angle Δθrt can be calculated by multiplying the right vehicle width angle Δθr by the right margin coefficient Cr. The left target shading angle ΔθLt corresponds to the horizontal length from the center M to the left edge of the first region R1. The left target shading angle ΔθLt can be calculated by multiplying the left vehicle width angle ΔθL by the left margin coefficient CL.
[0042] The upper target shading angle Δθut corresponds to the vertical length from the center M to the upper end of the first region R1. The upper target shading angle Δθut can be calculated by multiplying the upper vehicle height angle Δθu by the upper margin coefficient Cu. The lower target shading angle Δθdt corresponds to the vertical length from the center M to the lower end of the first region R1. The lower target shading angle Δθdt can be calculated by multiplying the lower vehicle height angle Δθd by the lower margin coefficient Cd.
[0043] Here, referring to Figures 6(a) to 7(b), we will explain the significance of defining the range of the first region based not only on the lateral position of the vehicle in front in the forward-facing image, but also on the speed at which the vehicle moves laterally in the forward-facing image.
[0044] Figure 6(a) shows the extent of the first region in a comparative example for a forward vehicle moving laterally. In Figure 6(a), the forward vehicle region FA and the first region R1A surrounding the forward vehicle V2, which is moving laterally near the center of the forward image, are shown. The extent of the first region R1A is defined by the positions corresponding to the shading lateral angles θArt and θBLt and the shading vertical angles θAut and θAdt, which are calculated using the basic margin coefficient without correction.
[0045] Figure 6(b) is a diagram showing the range of the first region in a comparative example where the vehicle in front of Figure 6(a) moves further laterally. In Figure 6(b), the forward vehicle region FB and the first region R1B are shown for a forward vehicle V2 that moves from near the center to the right in the forward image. The range of the first region R1B is defined by the positions corresponding to the lateral shading angles θBrt and θBLt and the vertical shading angles θBut and θBdt, which are calculated using the basic margin coefficient without correction.
[0046] In Figure 6(b), as the vehicle in front V2 moves, the right and left ends of the front vehicle region FB surrounding the vehicle in front V2 move to the right from the state in Figure 6(a). As a result, the right vehicle angle θr and left vehicle angle θL, from which the basic margin coefficient is read in the graphs of Figures 3(a) and 3(b), change to values to the right along the horizontal axis. Therefore, in the first region R1B, the margin on the right is larger compared to the first region R1A. However, if the movement speed of the vehicle in front V2 exceeds a predetermined value, for example, the processing speed of the light distribution control ECU 10 may become insufficient, and the vehicle in front V2 may deviate from the first region R1B, as in the example in Figure 6(b).
[0047] Figure 7(a) shows the extent of the first region in another comparative example when the vehicle in front of Figure 6(a) moves further laterally. In Figure 7(a), similar to Figure 6(b), the forward vehicle region FC and the first region R1C are shown for a forward vehicle V2 moving to the right from near the center in the forward image. The extent of the first region R1C is defined by the positions corresponding to the shading lateral angles θCrt and θCLt and the shading vertical angles θCut and θCdt, which are calculated using the basic margin coefficient without correction. However, in the example of Figure 7(a), the basic margin coefficient is set to a larger value than in the example of Figure 6(b) in anticipation of the deviation of the forward vehicle V2 from the first region R1B as in Figure 6(b). Therefore, in the first region R1C, the margin on the right is even larger compared to the first region R1B. However, in the first region R1C, the margin on the left is excessively large for the forward vehicle V2 moving to the right. Furthermore, if we assume, for example, that the vehicle in front V2 is not moving laterally in the forward-facing image, we would use a pre-defined large base margin coefficient, which could result in the first region becoming too wide.
[0048] Figure 7(b) shows the extent of the first region according to the embodiment when the forward vehicle in Figure 6(a) moves further laterally. In Figure 7(b), similar to Figure 6(b), the forward vehicle region FD and the first region R1D are shown for a forward vehicle V2 moving to the right from near the center in the forward image. The extent of the first region R1D is defined by the positions corresponding to the light-shielding lateral angles θDrt and θDLt calculated using the corrected right margin coefficient and left margin coefficient, and the light-shielding vertical angles θDut and θDdt calculated using the basic margin coefficient without correction. In the example of Figure 7(a), the movement speed of the forward vehicle V2 is greater than a predetermined value in the rightward direction. The right end, left end, top end, and bottom end of the first region R1D are calculated using the increased right margin coefficient Cr and the decreased left margin coefficient CL. Therefore, in the first region R1D, the right margin is even larger compared to the first region R1B. In the first region R1D, the left margin is smaller compared to the first region R1B. As a result, unlike the example in Figure 6(b), the forward vehicle V2 moving to the right is prevented from deviating from the first region R1D.
[0049] Furthermore, if we consider the case where the vehicle in front V2 is not moving laterally in the forward-facing image, for example, the movement speed of the vehicle in front V2 will be less than a predetermined value in the rightward direction, and therefore the basic margin coefficient that is not corrected using the offset amount will be used. Thus, unlike the example in Figure 7(a), the range of the first region will not become too wide for a vehicle in front V2 that is not moving laterally.
[0050] The light distribution control ECU 10 selects a group of LEDs from the LED matrix of the headlight 30 to be turned off. The light distribution control ECU 10 targets the group of LEDs corresponding to the first region R1 for the turn-off control. The group of LEDs to be turned off can be selected by a well-known method based, for example, on the horizontal shading angles θrt and θLt, the vertical shading angles θut and θdt, and the vehicle state. The light distribution control ECU 10 performs adaptive high beam control by turning off the selected group of LEDs and turning on the remaining LEDs.
[0051] [Operation of the light distribution control device] Next, the operation of the light distribution control device 100 will be described with reference to the drawings. Figure 8 is a flowchart showing an example of the processing of the ECU in Figure 1. The processing of the ECU in Figure 8 is performed, for example, when the ambient illuminance is below a predetermined ambient illuminance threshold. The ambient illuminance may be calculated by a well-known method based on the forward-facing image. The processing of the ECU in Figure 8 may also be performed when the vehicle speed is above a predetermined vehicle speed threshold.
[0052] As shown in Figure 8, the light distribution control ECU 10 of the light distribution control device 100 acquires the captured image and vehicle status in step S11. The light distribution control ECU 10 acquires a forward-facing image captured by the vehicle's camera of the vehicle in front of it. The light distribution control ECU 10 acquires at least the vehicle speed as the driving status. The light distribution control ECU 10 may also acquire the vehicle's acceleration and yaw rate as the driving status.
[0053] In step S12, the light distribution control ECU 10 calculates the vehicle angle of the vehicle in front. For example, the light distribution control ECU 10 calculates the vehicle angle of the vehicle in front based on the right edge position, left edge position, center position, upper edge position, and lower edge position of the forward vehicle region surrounding the vehicle in front in the forward image.
[0054] In step S13, the light distribution control ECU 10 calculates the vehicle width angle and the vehicle height angle. For example, the light distribution control ECU 10 calculates the vehicle width angle and the vehicle height angle based on the vehicle angle.
[0055] In step S14, the light distribution control ECU 10 calculates the margin coefficient (obtaining the right margin and left margin). The light distribution control ECU 10 may perform the process shown in Figure 9 as the calculation of the margin coefficient. Figure 9 is a flowchart showing an example of the margin coefficient calculation process in Figure 8.
[0056] As shown in Figure 9, in step S21, the light distribution control ECU 10 calculates the relative angular velocity of the vehicle in front. The light distribution control ECU 10 obtains the relative speed of the vehicle in front, for example, based on the detection result of the external sensor 20. The light distribution control ECU 10 calculates the relative angular velocity of the vehicle in front based on the vehicle's driving state and the relative speed of the vehicle in front.
[0057] In step S22, the light distribution control ECU 10 may calculate the relative angular acceleration of the vehicle in front. The light distribution control ECU 10 may, for example, calculate the relative angular acceleration based on the relative acceleration.
[0058] In step S23, the light distribution control ECU 10 determines whether or not a margin coefficient correction is required. For example, if the relative angular velocity of the vehicle in front is greater than or equal to a predetermined relative angular velocity threshold (predetermined value) in the rightward or leftward direction, the light distribution control ECU 10 determines that a margin coefficient correction is required.
[0059] If it is determined that no correction of the margin coefficient is required (S23: NO), in step S24, the light distribution control ECU 10 obtains the basic margin coefficient. After that, the light distribution control ECU 10 completes the process shown in Figure 9 and returns to the process shown in S15 of Figure 8.
[0060] If it is determined that a correction of the margin coefficient is required (S23: YES), in step S25, the light distribution control ECU 10 obtains the basic margin coefficient and calculates the offset amount.
[0061] In step S26, the light distribution control ECU 10 obtains a corrected margin coefficient corrected using the offset amount. The corrected margin coefficient is the right margin coefficient and left margin coefficient obtained by adding the offset amount to the basic margin coefficient. That is, if the movement speed of the vehicle in front in the forward-imaging image is greater than or equal to a predetermined value in the right direction, the light distribution control ECU 10 increases the right margin and decreases the left margin compared to the case where the movement speed is not greater than or equal to a predetermined value in the right direction. If the movement speed of the vehicle in front in the forward-imaging image is greater than or equal to a predetermined value in the left direction, the light distribution control ECU 10 increases the left margin and decreases the right margin compared to the case where the movement speed is not greater than or equal to a predetermined value in the left direction. After that, the light distribution control ECU 10 finishes the process shown in Figure 9 and returns to the process shown in S15 of Figure 8.
[0062] In step S15, the light distribution control ECU 10 calculates the target shading angle and defines the range of the first region (setting the range of the first region). The light distribution control ECU 10 uses the calculated margin coefficient to calculate the target shading angle and define the range of the first region.
[0063] In step S16, the light distribution control ECU 10 selects a group of LEDs to be switched off. In step S17, the light distribution control ECU 10 performs adaptive high beam control. After that, the light distribution control ECU 10 completes the process shown in Figure 8.
[0064] In the light distribution control device 100 described above, the light distribution control ECU 10 sets the range of the first region R1D based not only on the lateral position of the front vehicle V2 in the forward-imaging image, but also on the speed at which the front vehicle V2 moves laterally in the forward-imaging image. In this way, because the range of the first region R1D is set based not only on the lateral position of the front vehicle V2 in the forward-imaging image but also on its speed, the range of the first region R1D can be set in such a way that, for example, if there is a processing delay in the light distribution control ECU 10, the front vehicle V2 moving laterally in the forward-imaging image will not extend beyond the first region R1D. As a result, it is possible to prevent the range of the first region R1C from becoming too wide when the front vehicle V2 is not moving laterally in the forward-imaging image, by not expanding the range of the first region R1C too much in advance.Therefore, the light distribution control device 100 can set the range of the first region R1D more appropriately when the front vehicle V2 is moving laterally in the forward-imaging image compared to when it is based only on the lateral position of the front vehicle V2 in the forward-imaging image.
[0065] In the light distribution control device 100, the light distribution control ECU 10 acquires a right margin to expand the first region R1D to the right relative to the right edge position of the forward vehicle region FD that surrounds the forward vehicle V2 in the forward image. When the movement speed in the right direction is greater than or equal to a predetermined value, the light distribution control ECU 10 increases the right margin and decreases the left margin compared to when the movement speed in the right direction is not greater than or equal to a predetermined value. This allows the range of the first region R1D to be corrected laterally to match the forward vehicle V2 moving to the right in the forward image.
[0066] While embodiments of this disclosure have been described above, this disclosure is not limited to the embodiments described above. This disclosure can be implemented in various forms, including the embodiments described above, with various modifications and improvements based on the knowledge of those skilled in the art.
[0067] In the above embodiment, the movement speed of the forward vehicle V2 in the forward image was greater than or equal to a predetermined value in the rightward direction. However, the movement speed of the forward vehicle in the forward image may also be greater than or equal to a predetermined value in the leftward direction. In this case, the light distribution control ECU 10 acquires a left margin to expand the first region to the leftward relative to the left edge position, based on the left edge position of the forward vehicle region in the forward image. For example, when the movement speed is greater than or equal to a predetermined value in the leftward direction, the light distribution control ECU 10 increases the left margin coefficient CL compared to when the movement speed is not greater than or equal to a predetermined value in the leftward direction. For example, when the movement speed is greater than or equal to a predetermined value in the leftward direction, the light distribution control ECU 10 may decrease the right margin coefficient Cr compared to when the movement speed is not greater than or equal to a predetermined value in the leftward direction. In this case, for example, an offset amount can be used that corrects in the opposite direction to the vertical axis direction of the graphs in Figures 4(a) and 4(b), respectively.
[0068] In the above embodiment, the light distribution control ECU 10 corrects the right margin coefficient Cr and the left margin coefficient CL by adding or subtracting an offset amount along the vertical axis to set the range of the first region, but it is not limited to this example. For example, when the vehicle in front of the vehicle is located to the right of the vehicle and the speed of the vehicle in front is greater than or equal to a predetermined value in the rightward direction, the light distribution control ECU 10 may obtain the right margin coefficient Cr using a different offset amount along the horizontal axis to refer to a value further to the right of the graph in Figure 3(a). When the vehicle in front of the vehicle is located to the left of the vehicle and the speed of the vehicle in front is greater than or equal to a predetermined value in the leftward direction, the light distribution control ECU 10 may obtain the left margin coefficient CL using a different offset amount along the horizontal axis to refer to a value further to the left of the graph in Figure 3(b). In addition, the light distribution control ECU 10 may pre-set another map that reflects a correction value corresponding to the speed of the vehicle in front in the basic margin coefficient, and use this other map to obtain the right margin coefficient Cr and the left margin coefficient CL. In short, the light distribution control ECU 10 only needs to set the range of the first region based not only on the lateral position of the vehicle in front in the forward-imaging image, but also on the lateral movement speed of the vehicle in front in the forward-imaging image. [Explanation of symbols]
[0069] 10...Light distribution control ECU (control unit), 30...Headlight, 100...Light distribution control device, CL...Left margin coefficient, Cr...Right margin coefficient, F,FD...Forward vehicle area, IM...Forward image capture, R1,R1D...First area, V2...Forward vehicle.
Claims
1. A light distribution control device that controls the light distribution of headlights illuminating the area in front of a vehicle, The vehicle includes a control unit that controls the light distribution based on a forward-facing image captured by the vehicle's onboard camera, such that the illuminance of a first region including the vehicle in front of the vehicle is less than the illuminance of a second region not including the vehicle in front. The control unit, Based on the lateral position of the vehicle in front in the forward-imaging image and the lateral movement speed of the vehicle in front in the forward-imaging image, the range of the first region is set. Based on the right vehicle angle corresponding to the right end position of the forward vehicle region surrounding the forward vehicle in the forward image, a right margin coefficient is obtained to obtain a right margin for expanding the first region to the right with respect to the right end position. Based on the left vehicle angle corresponding to the left edge position of the front vehicle region in the forward-imaging image, a left margin coefficient is obtained to obtain a left margin for extending the first region to the left with respect to the left edge position. If the moving speed is greater than or equal to a predetermined value in the rightward direction, the right margin coefficient is increased and the left margin coefficient is decreased using an offset amount based on the moving speed. If the movement speed in the left direction is greater than or equal to a predetermined value, the left margin coefficient is increased and the right margin coefficient is decreased using the offset amount. A light distribution control device that sets the range of the first region based on the right margin coefficient and the left margin coefficient.
2. A light distribution control device that controls the light distribution of headlights illuminating the area in front of a vehicle, The vehicle includes a control unit that controls the light distribution based on a forward-facing image captured by the vehicle's onboard camera, such that the illuminance of a first region including the vehicle in front of the vehicle is less than the illuminance of a second region not including the vehicle in front. The control unit, Based on the lateral position of the vehicle in front in the forward-imaging image and the lateral movement speed of the vehicle in front in the forward-imaging image, the range of the first region is set. Based on the position of the rightmost edge of the forward vehicle region surrounding the forward vehicle in the forward image, a right margin coefficient for obtaining a right margin to extend the first region to the right with respect to the rightmost edge is obtained from a graph defining the relationship between the right vehicle angle corresponding to the rightmost edge and the margin coefficient. Based on the leftmost position of the front vehicle region in the forward-facing image, a left margin coefficient for obtaining a left margin to extend the first region to the left relative to the leftmost position is obtained from a graph defining the relationship between the left vehicle angle corresponding to the leftmost position and the margin coefficient. If the magnitude of the aforementioned movement speed is not greater than or equal to a predetermined value, the right margin coefficient and the left margin coefficient obtained from the graph are used as the basic margin coefficients. If the moving speed is greater than or equal to a predetermined value in the rightward direction, the basic margin coefficient is corrected using an offset amount based on the moving speed, so that the right margin coefficient is greater than the basic margin coefficient and the left margin coefficient is smaller than the basic margin coefficient. If the movement speed in the left direction is greater than or equal to a predetermined value, the basic margin coefficient is corrected using the offset amount, so that the left margin coefficient is greater than the basic margin coefficient and the right margin coefficient is smaller than the basic margin coefficient. A light distribution control device that sets the range of the first region based on the right margin coefficient and the left margin coefficient.
3. The light distribution control device according to claim 2, wherein the offset amount is the amount of movement that causes the curves of the right margin coefficient and the left margin coefficient to be shifted in parallel along the vertical axis direction of the graph of the margin coefficient.
4. The optical distribution control device according to claim 2 or 3, wherein the magnitude of the offset amount becomes larger as the relative angular velocity of the vehicle in front increases.
5. The light distribution control device according to claim 4, wherein the magnitude of the offset amount is adjusted according to the relative angular acceleration of the vehicle in front.
6. The light distribution control device according to claim 1 or 2, wherein when the control unit reduces the left margin coefficient or the right margin coefficient, the control unit controls the left margin coefficient or the right margin coefficient so that it does not become smaller than the guard value.