Other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings, in which:
An embodiment of the present invention will be described hereinbelow with reference to the drawings.
The illuminating device for a vehicle has a left headlamp 10 and a right headlamp 20. The left headlamp 10 mounted on the left side of the front face of a vehicle illuminates the front left side of the vehicle, and includes a high-beam lamp 11, a low-beam lamp 12, and a drive controller 13. The high-beam lamp 11 is a lamp for a high beam, and the low-beam lamp 12 is a lamp for a low beam. The drive controller 13 drive-controls the high-beam lamp 11 and the low-beam lamp 12 (controls a lamp application voltage). Similarly, the right headlamp 20 mounted on the right side of the front face of the vehicle illuminates the front right side of the vehicle, and includes a high-beam lamp 21, a low-beam lamp 22, and a drive controller 23. The high-beam lamp 21 is a lamp for a high beam, and the low-beam lamp 22 is a lamp for a low beam. The drive controller 23 drive-controls the high-beam lamp 21 and the low-beam lamp 22 (controls a lamp application voltage).
The illuminating device for a vehicle has a headlamp controller 30. The headlamp controller 30 includes a light distribution determining/controlling unit 32 and a swivel/leveling determining unit 31.
Each of headlamp driving mechanisms 41 and 42 includes a leveling mechanism of adjusting the optical axis in the vertical direction and a swivel mechanism of varying an illumination range and direction by moving the optical axis or the headlamp itself in the horizontal direction. The headlamp driving mechanisms 41 and 42 are driven by a motor and the like. Switching and the like of the high-beam lamps 11 and 21 and the low-beam lamps 12 and 22 can be performed by controlling the drive controllers 13 and 23 of the headlamps 10 and 20 by using the headlamp controller 30 (the light distribution determining/controlling unit 32). By controlling the headlamp driving mechanisms 41 and 42 by using the headlamp controller 30 (the swivel/leveling determining unit 31), the adjustment of the optical axis in the vertical direction of the headlamps 10 and 20 by the leveling mechanism and the adjustment of the illumination range and direction by the swivel mechanism can be performed.
To the headlamp controller 30, a display 43, an in-vehicle front environment detector 44, a headlamp operating switch 45, an engine starter 46, a wiper device 47, a vehicle speed sensor 48, a steering angle sensor 49, a vehicle state sensor 50, and a road information provider (navigator) 51 are connected.
The display 43 is provided to notify the driver of the state of a headlamp presently used, and is disposed as an indicator in an instrument panel or the like.
The in-vehicle front environment detector 44 is an apparatus for determining vehicle front environment in the front field in the travel direction. The details will be described later.
The headlamp operating switch 45 is normally disposed near the steering wheel and can be manually operated by the driver. As operating modes, a light-out mode, a low-beam mode, a high-beam mode, and an automatic mode are provided. When the headlamp operating switch 45 is set in automatic mode, the in-vehicle front environment detector 44 is used.
The engine starter 46 outputs a start signal on start of the engine. The wiper device 47 outputs a wiping speed signal. The vehicle speed sensor 48 outputs a vehicle speed signal. The steering angle sensor 49 outputs a steering state signal. The vehicle state sensor 50 is a yaw rate sensor, an inclination sensor, or the like and outputs a vehicle state signal. The road information provider (navigator) 51 outputs an information signal of a road shape or the like. The headlamp controller 30 and the in-vehicle front environment detector 44 obtain those signals (the start signal, wiping speed signal, vehicle speed signal, steering state signal, vehicle state signal, navigation signal, and the like).
In
The control circuit unit 70 is formed by a drive controller 72, an image input interface (I/F) 73, and an arithmetic processor 71. The drive controller 72 drives the image sensor unit 60. The image input interface (I/F) 73 obtains an image subjected to A/D conversion performed by the A/D converter 63. The arithmetic processor 71 is formed mainly by a CPU and, when it is set in the automatic mode, performs a process of analyzing an image and controls the headlamps.
Next, the action of the illuminating device for a vehicle will be described.
A signal for starting the image sensor unit 60 is output from the control circuit unit 70 in
In
In such a manner, the arithmetic processor (CPU) 71 processes the image obtained by the imaging device 62 and determines the brightness of the environment in which the vehicle travels. More specifically, an average level of gray in a preset range on a captured image of the front of the vehicle in the travel direction is calculated and compared with a preset gray-level value (threshold), thereby determining the brightness of the environment in which the vehicle travels. Alternatively, the number of light sources in a preset range on a captured image of the front of the vehicle in the travel direction is calculated and compared with a preset value (the number of light sources), thereby determining the brightness of the environment in which the vehicle travels.
The “preset range on an image” can be set in consideration of the parameters of the in-vehicle front environment detector (i.e., mount requirements such as mount height, angle of view, angle of depression, and the like), road conditions (i.e., road design basic requirements such as width of road, radius of curvature, and gradient), parameters of lightings on roads (i.e., basic requirements for mounting lightings on roads such as attachment height and intervals), and delineator parameters (i.e., basic requirements of mounting such as attachment height and intervals).
When a road light as a lighting on a road exists, the arithmetic processor (CPU) 71 determines that the travel environment is light in Step S101, moves to Step S102, and outputs a low-beam-mode signal (L mode sig. in
On the other hand, when the arithmetic processor (CPU) 71 determines that the travel environment is not light in Step S101, whether another high-brightness light source exists in the preset range on the image or not is determined in Step S103. A process of extracting a high-brightness light source is performed to extract a light source estimated as the light source of an oncoming vehicle at high probability in consideration of the relations that brightness of a tail lamp of a preceding vehicle is generally lower than that of a road light, and the brightness of a road light is generally lower than that of the headlamp of an oncoming vehicle. A high-brightness light source is a light source having gray level equal to or higher than a preset threshold value.
After the high-brightness light source is extracted in Step S103, the arithmetic processor (CPU) 71 moves to Step S104 and determines traceability. When the high-brightness light source has been traced for a predetermined period, the arithmetic processor (CPU) 71 determines that the light source is (the headlamp of) an oncoming vehicle.
In such a manner, the arithmetic processor (CPU) 71 extracts the light source of high brightness in the preset range on the captured image of the front of the vehicle in the travel direction and traces the light source, thereby determining the presence or absence of an oncoming vehicle. When it is determined that there is (the headlamp on an oncoming vehicle, the arithmetic processor (CPU) 71 moves to Step S102 and outputs the low-beam-mode signal. In response to the signal, illuminating operation is performed with the low-beam lamp (low beam is emitted) by the headlamp controller 30.
In Step S104, a determination is made in consideration of a movement change, a shape change, and the like of the high-brightness light source. The “movement” is considered on the basis of the fact that if the light source is an oncoming vehicle, the relative speed is high, so that the movement amount of the light source is large. The “shape change” is considered on the basis of the fact that if the light source is an oncoming vehicle, the vehicle approaches, so that the build of the light source gradually increases. When the change tendencies are different from the above, the light source is determined as ambient light.
When the light source is determined as ambient light by the determination of traceability in Step S104, the arithmetic processor (CPU) 71 moves to Step S105 and outputs a travel mode signal. In response to the signal, illuminating operation is performed with the high-beam lamp (high beam is emitted) by the headlamp controller 30.
When a high-bright light source is not extracted in Step S103, the arithmetic processor (CPU) 71 moves to Step S106, and determines whether or not a light source having symmetry exists in the horizontal direction in the preset range on the image. The operation is performed in consideration of the fact that the lightings of a vehicle are bilaterally symmetrical, and it is effective for determining whether the light source is the light source of a vehicle or not.
Specifically, when the vehicle width is set as 1.8 m and one side of a lighting of the vehicle is set as 0.2 m, the interval between the lightings of the vehicle is about seven times as wide as the build of the vehicle lighting. Consequently, the interval between the light sources which are symmetrical on the image is calculated, and whether the light source is a light source corresponding to the vehicle light or not is determined by comparing the calculated interval with an expected interval and comparing the build of the light source with an expected build. In addition, the symmetrical light sources having similar sizes are selected for the reason that even if the interval is an expected interval, the possibility that the light sources whose sizes are largely different from each other are ambient light is high.
When symmetrical light sources are extracted in Step S106, the arithmetic processor (CPU) 71 moves to Step S107 and determines traceability. When the symmetry is traced for predetermined time, the light sources are determined as those of a vehicle. The traceability is determined also in consideration of a change in the interval between symmetrical light sources, a change in build, a change in the brightness of the light source, a movement amount, a movement direction, and the like.
As described above, the arithmetic processor (CPU) 71 extracts light sources which are symmetrical in the horizontal direction in the preset range on the image of the front of the vehicle in the travel direction and traces the light sources, thereby determining the presence or absence of another vehicle. When the arithmetic processor (CPU) 71 determines that there is another vehicle (headlamp or tail lamp), the arithmetic processor (CPU) 71 moves to Step S102 and outputs a low-beam-mode signal. In response to the signal, illuminating operation is performed with the low-beam lamp (low beam is emitted) by the headlamp controller 30. When the light source is determined as ambient light from the determination of traceability, the arithmetic processor (CPU) 71 moves to Step S105 and outputs a high-beam-mode signal (H mode sig. in
On the other hand, when symmetrical light sources are not extracted in Step S106, the arithmetic processor (CPU) 71 moves to Step S108 and extracts a light source having preset gray level in a preset range on an image. The “preset gray level” denotes a gray level band having a range like a bandpass having the lower and upper limits. Specifically, the gray level band of a preceding vehicle is preset in consideration of the tendency that brightness of (tail lamp) of a preceding vehicle is lower than brightness of a road light, and the brightness of a road light is lower than that of (the headlamp of) an oncoming vehicle.
When the light source is extracted in Step S108, the arithmetic processor (CPU) 71 moves to Step S109 and determines traceability. The traceability is determined in consideration of a change in the build of the light source, a movement amount, a movement direction, and the like in a manner similar to Steps 104 and 107. When the light source has been traced for a predetermined period, the arithmetic processor (CPU) 71 determines that the light sources are those of a vehicle.
The trace time upon determination of the traceability of the extracted light source is predetermined time (continuous image frames) in which fluctuations in the light source position according to exposure time are considered. The time may be changed using, as elements, ups and downs in the road surface and the like. That is, the time of tracing the light source at the time of determining the presence or absence of a vehicle by tracing the light source may be changed on the basis of travel information (such as vehicle speed, steering angle, yaw rate, and inclination of the vehicle) of the vehicle (in a manner similar to Steps 104 and 107). Concretely, the time of tracing the light source is adjusted by using information indicative of the vehicle states from the vehicle speed sensor 48, the steering angle sensor 49, the vehicle state sensor 50, and the like. For example, when a vehicle travels at high speed, the light source trace time is shortened. The operation is preferable to optimize the light source trace time.
When a light source is not traced in predetermined time of tracing a light source at the time of determining the presence or absence of a vehicle by tracing a light source, the presence of a vehicle may be estimated on the basis of travel information (vehicle speed, steering angle, yaw rate, inclination of the vehicle, and the like) of the vehicle (in a manner similar to Steps 104 and S107). Concretely, even if a light source is not traced in predetermined time for tracing a light source, the presence of a vehicle is estimated by using information indicative of vehicle states from the vehicle speed sensor 48, the steering angle sensor 49, and the vehicle state sensor 50. It corresponds to, for example, the time when a vehicle travels at high speed or travels on a curved road. The operation is preferable to optimize the trace of the light source.
As described above, in Steps 108 and S109, the arithmetic processor (CPU) 71 extracts a light source having a preset gray level in a preset range on an image of the front of a vehicle in the travel direction, and traces the light source, thereby determining the presence or absence of another vehicle. When it is determined that another vehicle (headlamp or tail lamp) exists, the arithmetic processor (CPU) 71 moves to Step S102 and outputs a low-beam-mode signal. In response to the signal, illuminating operation is performed with the low-beam lamp (low beam is emitted) by the headlamp controller 30. When the light source is determined as ambient light from the determination of traceability and when no light source is extracted in Step S108, the arithmetic processor (CPU) 71 determines that there is no vehicle, moves to Step S105, and outputs a high-beam-mode signal. In response to the signal, illuminating operation is performed with the high-beam lamp by the headlamp controller 30 (high beam is emitted).
In such a manner, by the processes of Steps S102 and S105, the headlamp as the illuminating device for a vehicle is controlled optimally in various travel environments, so that visibility of the driver can be improved. For example, in an environment with the small number of road lights, the high-beam lamp is used. When a preceding or oncoming vehicle exists, the low-beam lamp is used to prevent the driver of the other vehicle from being dazzled.
Though switching between the headlamps 10 and 20 is controlled as the processes in Steps S102 and S105, light distribution of the headlamps 10 and 20 may be controlled. Alternatively, both of the control of switching between the headlamps 10 and 20 and the control of light distribution may be performed. Specifically, at least one of the switching between the headlamps 10 and 20 of the vehicle and the light distribution is controlled on the basis of a determination result of the environment in which the vehicle travels and a determination result of the presence or absence of another vehicle. The “switching between the headlamps” at the time of controlling at least one of the switching between headlamps 10 and 20 of the vehicle and the light distribution denotes switching between the low-beam lamp and the high-beam lamp, and the “light distribution” denotes a change in the illumination distance and direction or adjustment of an illumination amount (lighting control) by changing the optical axis of light emitted. Those operations can be performed by using an adaptive front-lighting system (AFS) or an optical axis adjusting mechanism (auto leveling system) introduced in recent years.
At the time of controlling one of the switching between the headlamps 10 and 20 of the vehicle and the light distribution, the arithmetic processor (CPU) 71 may change the control speeds (switching speed and light distribution speed) on the basis of the travel information (vehicle speed, steering angle, yaw rate, inclination of the vehicle, and the like) of the vehicle. Concretely, the time required to switch the headlamp may be varied by using the information indicative of the vehicle states from the vehicle speed sensor 48, the steering angle sensor 49, the vehicle state sensor 50, and the like. For example, the headlamp is switched swiftly when the vehicle travels at high speed, and is switched slowly when the vehicle travels on a curved road or the like. The operation is preferable to optimize the control speed of the headlamps of the vehicle.
The action will now be described by using image examples of
Generally, in the mounting position, the height is about 1.5 m. In
By the process of Step S101 in
By the processes in Steps S103, S106, and S108 in
The ranges 90 and 91 in
For example, as shown in
The above operations are preferable for optimization.
The range 91 for determining the presence or absence of another vehicle will be mentioned. When the light amount characteristics of vehicle lights such as the headlamp and the tail lamp in a distance from another vehicle are considered and the size and symmetry of light sources extracted from an image are provided, the upper and lower limits of the range 91 can be also finely adjusted from the distance calculated from the interval of the light sources (estimated distance). For example, when the brightness is high, it is estimated that the distance is short, and the upper and lower limits are finely adjusted.
The in-vehicle front environment detector 44 in
By the embodiment, the following effects can be obtained.
(1) In the configuration of the in-vehicle front environment detector 44, the arithmetic processor (CPU) 71 processes an image obtained by the imaging device 62, determines the brightness of the environment in which the vehicle travels and, when it is determined that the environment in which the vehicle travels is dark, processes the image obtained by the imaging device 62 to determine the presence or absence of another vehicle. Therefore, considering the brightness of the environment in which the vehicle travels (the night visibility of the driver), whether the road environment requires the vehicle detection and determination or not is determined. When the vehicle detection and determination is necessary, the vehicle detection can be performed. That is, necessity of determining the presence or absence of other vehicles can be easily determined. Without using two optical systems (i.e., without increasing the cost) and without performing high-speed imaging or high-level signal process, vehicle detection can be performed easily as necessary. Further, without using high-level image analyzing process for extracting a preceding vehicle and an oncoming vehicle from a captured image, vehicle detection can be performed easily as necessary.
Particularly, the range 90 for determining the brightness of the travel environment and the range 91 for determining the presence or absence of another vehicle are predetermined ranges on a captured image. Consequently, as compared with the case of making determination in the whole image range, the arithmetic process load can be lessened.
(2) The processor 71 is employed to appropriately control the selective switching and/or the intensity control of the headlamps 10, 20 based on the detection result of the brightness and other vehicles.
(3) The processor 71 is employed to appropriately control the headlamps 10, 20 according to the vehicle information such as the vehicle speed, the steering angle, the yaw rate, the vehicle body angle (inclination), and the information from an outside information source. For example, the vehicle speed may be correlated with the detection area in the image, the steering angle may be correlated with the detection area, and the vehicle body angle may be correlated with the detection area.
Although the present invention has been fully described in connection with the preferred embodiment thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art.
That is, signals from the vehicle speed sensor 48, the steering angle sensor 49, the vehicle state sensor 50, and the road information provider 51 may be totally considered for controlling the headlamps 10, 20 in addition to the signals from the in-vehicle front environment detector 44. In other words, the vehicle information in addition to the brightness and other vehicle is used to control the headlamps 10, 20.
For example, the automatic mode may only be used for the vehicle speed of 50 km/h or more. Or, the low beam may only be used for a hill climb. Or, the optical axis of the headlamps 10, 20 may be swiveled according to the steering angle or the like when the vehicle is turning right or left.
Such changes and modifications are to be understood as being within the scope of the present invention as defined by the appended claims.
Number | Date | Country | Kind |
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2006-122250 | Apr 2006 | JP | national |