JPH06321007A - Automotive glare sensor - Google Patents

Abstract

(57) [Summary] [Purpose] The color of the light source is clearly identified and detected regardless of the perspective of the target light source to be identified. [Configuration] CC on the rear optical axis L of the zoom objective lens 1
The D image pickup devices 10 and 12 are arranged, and the light flux incident on the objective lens 1 is condensed on the surfaces of the CCD image pickup devices 10 and 12 to discriminate the color of the incident light flux. The objective lens 1 is configured by a zoom type lens system in which the focal position of the lens system is displaced by the lens driving device 4 and is always focused on the CCD image sensor surface, or a plurality of lenses having different focal lengths are arranged in parallel. Each objective lens 1a, 1b, 1c is composed of a lens system.
It is configured by a plurality of lens systems for each focal length in which a pair of CCD image pickup devices 10 and 12 are arranged on the rear optical axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle glare sensor for identifying a preceding vehicle or an oncoming vehicle in front of an automobile and controlling the light distribution of a headlight of the vehicle.

[0002]

2. Description of the Related Art Conventionally, a headlight of an automobile has a function of changing a light distribution of an irradiation light flux depending on whether the vehicle is traveling normally or passing a vehicle to prevent dazzling of an oncoming vehicle and ensure driving safety. A variable light distribution type headlight is used.

However, in the conventional variable light distribution type headlight, the driver actually switches the light distribution manually, and the headlight is frequently used while driving the vehicle on a road where driving conditions are different. Switching the light distribution of the lamp complicates the driving operation and is not preferable for safe driving.

Therefore, in order to control the light distribution of the headlight of the automobile by discriminating the preceding vehicle or the oncoming vehicle existing in front, a glare sensor as shown in FIG. 11 is conventionally known. There is. That is, a beam splitter 51 composed of a half mirror is attached at an inclination angle of 45 degrees with respect to the optical axis L on the optical axis L behind the objective lens 50 that forms an image of an object existing in the front field of view of an automobile at a predetermined position. At the same time, an infrared cut filter 52, on the transmitted light axis L1 and a reflected light axis L2 of the beam splitter 51, respectively.
CCD elements 53 and 55 are provided via 54.

The beam splitter 51 has a multilayer film structure that transmits yellow light in the direction of the transmitted light axis L1 and reflects blue light in the direction of the reflected light axis L2, and cuts infrared rays on the transmitted light axis L1. The filter 52 has a structure using a yellow or red filter, and the infrared cut filter 54 on the reflection optical axis L2 uses a blue filter.

The dazzling sensor constructed as described above forms an image of the light flux of the tail lamp of the preceding vehicle or the light flux of the head lamp of the oncoming vehicle existing in the forward field of view of the vehicle on the CCD elements 53 and 55. , Its presence is detected, and the light distribution of the headlamps of the own vehicle is variably controlled to a preferable state by this detection signal, so that the glare to other vehicles is eliminated.

[0007]

However, since the objective lens 50 has a fixed focus in the above-mentioned conventional glare sensor,
When the light source to be identified is at a long distance, the image on the CCD element surface becomes too small, and when it is at a short distance, the image on the CCD element surface is blurred, so the S / N ratio becomes small and the object detection performance is reduced. It had the problem of getting worse.

The present invention was devised in view of the above problems, and automatically identifies a preceding vehicle or an oncoming vehicle in front of an automobile to automatically control the light distribution of the headlight of the vehicle. It is an object of the present invention to provide an automotive glare sensor capable of clearly identifying and detecting the color of a light source regardless of the distance of a target light source to be identified.

[0009]

In a vehicle glare sensor according to the present invention, a CCD image pickup device is arranged on the rear optical axis of an objective lens, and a light beam incident on the objective lens is condensed on the CCD image pickup device surface. In a car glare sensor for determining the color of an incident light flux, (1) a zoom lens for controlling an objective lens so that a focal point of a lens system is displaced by a lens driving device so that the objective lens is always focused on a CCD image sensor surface. It is composed by the system. (2) The objective lens is configured by a plurality of lens systems in which lenses having different focal lengths are arranged in parallel, and a plurality of lens systems for each focal length in which a pair of CCD image pickup devices are arranged on the rear optical axis of each objective lens. Constitute. This is the summary.

[0010]

In the configuration (1), the focal position of the zoom type objective lens is displaced by the lens driving device according to the distance of the vehicle to be detected, and the focal position is constantly changed so as to form an image on the CCD image pickup element surface. Therefore, when the target vehicle is distant, the zoom type objective lens operates so as to extend the focal position, and the lamp image of the preceding vehicle or the oncoming vehicle is enlarged and formed on the CCD image pickup element surface.

In the case of (2), when the target vehicle is distant from the plurality of lens systems, the lens system having a long focal length is selected, and the lamp image of the preceding vehicle or the oncoming vehicle is C
A magnified image is formed on the surface of the CD image sensor.

In this way, the image of a distant object is magnified to C
The identification performance is improved by imprinting on the surface of the CD image pickup device.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the automotive glare sensor according to the present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment using a zoom type optical system, FIG. 1 is a vertical cross-sectional view of an automobile glare sensor, and FIG. 2 is an enlarged view of a lens driving device section.

Reference numeral 1 denotes a zoom type objective lens formed in the tubular portion 3 of the housing 2, and a lens driving device for the first lens system fixed to the tip of the tubular portion 3 and the first lens system. Four
And a second lens system which is displaced by. The first lens system is composed of a fixed lens 5 made of a convex lens, and the second lens system is slidably inserted in the cylindrical portion 3 in parallel with the optical axis L of the fixed lens 5. The moving lens 7 is configured by a concave lens fixedly mounted on the sliding cylinder 6.

The sliding cylinder 6 is controlled so as to be displaced in the optical axis L direction via a lens driving device 4 described later,
The movable lens 7 is moved in the optical axis L direction with respect to the fixed lens 5 to change the relative distance, thereby changing the focal position of the zoom type objective lens 1. The zoom type objective lens 1
The first lens system and the second lens system can be combined in various ways, but in this embodiment, the fixed lens 5 of the first lens system is a convex lens The moving lens 7 of the two-lens system is composed of a combination of concave lenses.

On the optical axis L behind the fixed lens 5, a beam splitter 8 consisting of a half mirror having a multilayer film structure is provided.
Is attached with an inclination angle of 45 degrees with respect to the optical axis L, and the rear transmission optical axis L of the beam splitter 8 is attached.
CCD image sensor 1 via red filter 9 at the upper position
Place 0. Further, a CCD image pickup device 12 is arranged on the back reflection optical axis L2 of the beam splitter 8 via a blue filter 11. As shown in FIG. 3, it is desirable that both CCD image pickup devices 10 and 12 are vertically asymmetric with respect to the horizontal axis H and have an upper portion wider than a lower portion, and an image pickup surface is horizontally long.

The inner surface of the fixed lens 5 is coated with an infrared cut film 13 in the form of a selectively transmitted light thin film.

In the lens driving device 4, the connecting pin 14 projecting from the sliding barrel 6 is bored in the tubular portion 3 and led out from the elongated hole 15 extending in the optical axis L direction. It is slidably engaged with a helical groove 17 of a helical cylinder 16 which is rotatably inserted. The gear 18 formed on the outer periphery of the end of the helical cylinder 16 meshes with a drive gear 20 axially attached to the drive shaft of a control motor 19 which is attached to the casing 2 by means of a small screw or the like and which is capable of forward and reverse control. Motor 19
The connecting pin 14 engaged with the helical groove 17 is displaced in the axial direction of the cylinder by the rotational driving of, and the movable lens 7 is displaced forward and backward along the optical axis L.

In the automobile glare sensor constructed as described above, the moving lens 7 of the zoom type objective lens 1 is displaced by the lens driving device 4 according to the distance of the vehicle to be detected, and C
The focus position is changed so as to form an image on the surface of the CD image pickup device 10 or 12 (see FIG. 4), and the distance between the own vehicle and the detection target vehicle is measured by, for example, a known infrared distance measuring device 21. , The control motor 19 via the central control unit 22
Is rotated by a preset rotation angle to displace the moving lens 7 to a predetermined position via the helical mechanism.

When the lamp image TL is detected on the CCD image pickup device 10 side on the transmitted light axis L1, this is detected as a "taillight of the preceding vehicle" and the headlight of the own vehicle is deflected downward. Change the direction of the light flux. Further, when the lamp image HL is detected on the CCD image pickup device 12 side on the reflected light axis L2, this is detected as the “headlight of the oncoming vehicle” and the headlight of the own vehicle is deflected diagonally leftward ( This is a detection signal for automatically performing optical axis deflection processing such as changing the direction of the light flux as in the case of left-hand traffic.

The infrared distance measuring device 21 has a light emitting and receiving unit and irradiates a pulsed near infrared laser beam from a laser radar to the front, and the rear of the car (in the case of a preceding car) or the front of the car (in the case of an oncoming car). ) The reflected light from the reflector is used to receive light, and at the same time, a half of the speed of light from light emission to light reception is calculated by the arithmetic circuit as the distance to the target vehicle.

Therefore, when the target vehicle is distant, the moving lens 7 is displacement-controlled so as to be closer to the fixed lens 5 side (see the solid line in FIG. 1), and the lamp image of the preceding vehicle and / or the oncoming vehicle is CCD imaged. An image is formed on the surfaces of the elements 10 and 12. By displacing the moving lens 7 in this way, a clear image can always be obtained on the surfaces of the CCD image pickup devices 10 and 12.
Since the image of the distant target vehicle is enlarged, the discrimination performance is improved.

In measuring the distance between the own vehicle and the target vehicle,
Although the one using the infrared distance measuring device 21 has been described, since the preceding vehicle and the oncoming vehicle are present as the target vehicles, the CCD image pickup device 10 on the transmitted light axis L1 side is used,
It is also possible to measure the distance D from the image forming position (see FIG. 5).

Assuming that the focal length of the fixed lens 5 is f1, the focal length of the moving lens 7 is f2, and the distance between both lenses is d, the focal length f'from the moving lens 7 when both lenses are combined is 1 / F '= 1 / (f1-d) + 1 / f2 and the theoretical focal length f is 1 / f = 1 / f1 + 1 / f2-d / f1 × f2. Therefore, as shown in FIG. 5A, if the lamp image G is located above the horizontal line H passing through the optical axis O on the surface of the CCD image sensor 10, if f * tan θ = h tan θ = (HS−HL) / D ( HS: sensor mounting height HL: lamp mounting height), the distance D between the own vehicle and the target vehicle is calculated by this calculation.
Can be calculated, and the lens driving device 4 is controlled and driven via the central control device 22 to displace the moving lens 7 to a preferable position.

In the measurement of the distance D using the CCD image pickup device 10, images of a plurality of light emitters (lamps) may be present on the surface of the CCD image pickup device 10 at the same time. By performing image processing so as to select a luminance image, it is possible to perform measurement in the same manner as above.

FIG. 6 and FIG. 7 show a second embodiment of the automobile glare sensor according to the present invention. In this embodiment, instead of the zoom type objective lens 1 constructed in the first embodiment, a long distance fixed lens 1a, a middle distance fixed lens 1b, and a short distance fixed lens 1a which are convex lenses having different focal lengths are used. The fixed lenses 1c are provided side by side as objective lenses, and the beam splitter 8 and the two CCD image pickup devices 10 and 12 are provided behind the fixed lenses 1a, 1b and 1c, respectively, in the same manner as in the first embodiment. For long distance,
The sensor unit is configured for medium distance and short distance.

In the above structure, the long distance fixed lens 1a,
Fixed lens 1b for medium distance and fixed lens 1c for short distance
Is used as an objective lens, and the view angles ω1, ω2, and ω3 are different according to the distance between the identification target vehicle and the own vehicle (the view angle on the near distance side is set to be larger than the view angle on the far distance side). .)
It is structured so that the image formation on the CCD image pickup devices 10 and 12 is substantially constant.

As described above, depending on the distance to the target vehicle, a clear image is always displayed on the surfaces of the CCD image pickup devices 10 and 12 by detecting with the dedicated sensor units for long distance, medium distance, and short distance. Is obtained and the image in the case of a distant target vehicle does not become small, so that the discrimination performance is improved.

Further, FIGS. 8 and 9 show a third embodiment of the automotive glare sensor according to the present invention. In the present embodiment, in the second embodiment, a large number of optical fibers 23, 23 are provided between the focal plane position (arrow A) of each fixed lens 1a, 1b constituting the objective lens by the convex lens and the beam splitter 8. (A light guide lens may be used) to provide optical conduction. In the embodiment, it is composed of a pair of long-distance sensor parts and a pair of short-distance sensor parts.

In the structure of this embodiment, the fixed lens 1a,
Since the optical fibers 23, 23 ... Guide light between the focal plane position (arrow A) of 1b and the beam splitter 8, even if the focal plane position A differs between the long distance sensor unit and the short distance sensor unit, C via beam splitter 8
The amount of light incident on the surfaces of the CD image pickup devices 10 and 12 can be made substantially constant.

The beam splitter 8 for distinguishing between the taillight and the headlight in each of the embodiments of the present invention has been described above as having a multi-layered film structure using an interference film. As shown in FIG. 10, the structure of the beam splitter 8 is such that a prism-shaped reflecting mirror 25 is arranged on the rear optical axis L of the objective lens 1 via a light guide 24, and the reflected light flux is paired with a pair of CCDs. Image sensor 10, 1
It is also possible to configure so as to receive light by two. Reference numeral 26 is a blue filter.

[0032]

As described above, the vehicle glare sensor according to the present invention has an objective lens for condensing light when the luminous flux from the vehicle lamp in the front field of view is received by the CCD image pickup element surface to detect the lamp color. By using a zoom type or a plurality of objective lenses that are selectively used depending on the distance, even a distant image can be largely received on the CCD image pickup element surface, and the S / N ratio is improved. Therefore, the color of the light source can be clearly identified and detected irrespective of the distance of the target light source to be identified, and a good object detection performance is demonstrated to automatically detect a preceding vehicle or an oncoming vehicle in front of the vehicle. The characteristics of the present invention can be identified, and the effect obtained by implementing the present invention is extremely large.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view showing a first embodiment of an automotive glare sensor according to the present invention.

FIG. 2 is an enlarged view showing an embodiment of the lens driving device section.

FIG. 3 is a front view of a CCD image pickup device.

FIG. 4 is an explanatory diagram showing image formation on the surface of a CCD image pickup device.

5A and 5B are explanatory diagrams showing a distance measuring method using an image of a CCD image pickup element surface.

FIG. 6 is a schematic vertical cross-sectional view showing a second embodiment.

FIG. 7 is a schematic cross-sectional view of the same.

FIG. 8 is a schematic vertical sectional view showing a third embodiment.

FIG. 9 is a schematic cross-sectional view of the same.

FIG. 10 is a schematic view of a main part showing another embodiment of the beam splitter.

FIG. 11 is a schematic vertical sectional view showing an example of a conventional automotive glare sensor.

[Explanation of symbols]

 1 Zoom type objective lens 1a Fixed lens for long distance 1b Fixed lens for medium distance 1c Fixed lens for short distance 4 Lens driving device 5 Fixed lens 6 Sliding cylinder 7 Moving lens 8 Beam splitter 9 Red filter 10 CCD image sensor 11 Blue filter 12 CCD image sensor 13 infrared cut film 19 control motor 21 infrared distance measuring device 22 central control device 23 optical fiber

Claims (1)

[Claims] 1. A dazzling sensor for an automobile in which a CCD image pickup device is arranged on the rear optical axis of an objective lens, and a light beam incident on the objective lens is condensed on a surface of the CCD image pickup device to determine the color of the incident light beam. The objective lens is composed of a zoom type lens system which is controlled so that the focal position of the lens system is displaced by a lens driving device and is always focused on the CCD image pickup device surface, or the objective lens has different focal lengths. For a vehicle characterized by comprising a plurality of parallel lens systems, and a plurality of lens systems for each focal length in which a pair of CCD image pickup devices are arranged on the rear optical axis of each objective lens. Glare sensor.