WO2016185980A1

WO2016185980A1 - Window surface detection sensor

Info

Publication number: WO2016185980A1
Application number: PCT/JP2016/064042
Authority: WO
Inventors: 翔鷹野; 圭吾疋田
Original assignee: アスモ株式会社
Priority date: 2015-05-19
Filing date: 2016-05-11
Publication date: 2016-11-24

Abstract

This window surface detection sensor is constituted so as to obtain information of the surface of a vehicle window by capturing an image of the vehicle window from the vehicle interior. The window surface detection sensor includes an image capture element that has an image capture surface, and a lens that has a principal surface. The image capture surface of the image capture element and the principal surface of the lens extend in a mutually non-parallel manner such that a plane including the image capture surface, a plane including the principal surface, and a plane including the outer surface of the vehicle window intersect on a straight line.

Description

Wind surface detection sensor

The present invention relates to a window surface detection sensor.

Some vehicles control a wiper based on the brightness of an image obtained by imaging a vehicle window (outside the vehicle window) from the inside of the vehicle with an imaging device (see, for example, Patent Document 1). In such a vehicle, the wiper can be automatically driven to wipe away raindrops and the like on the outer surface of the vehicle window.

JP 2014-133425 A

However, the above-described vehicle predicts and determines the amount of raindrops based on the brightness of the image. For example, when there is a light source in the background outside the vehicle, there is a risk of making an erroneous determination. This causes the wiper to be operated more than necessary due to an erroneous determination.

It is an object of the present invention to provide a window surface detection sensor that can obtain information on the outer surface of a vehicle window with high definition.

In order to achieve the above object, a window surface detection sensor according to an aspect of the present invention is configured to obtain an image of a surface of a vehicle window by imaging the vehicle window from the inside of the vehicle. The window surface detection sensor includes an imaging device having an imaging surface and a lens having a main surface. The imaging surface of the imaging device and the main surface of the lens are not parallel to each other so that a plane including the imaging surface, a plane including the main surface, and a plane including the outer surface of the vehicle window intersect in a straight line. It extends to.

1 is a schematic cross-sectional view of a vehicle according to an embodiment of the present invention. The schematic cross section of the vehicle in another example. The front view of the windshield in another example. The schematic cross section of the vehicle in another example.

Hereinafter, an embodiment of a vehicle will be described with reference to FIG.
As shown in FIG. 1, the vehicle C is provided with a windshield 2 as a vehicle window so as to extend obliquely downward from the vehicle front side end portion of the roof panel 1 toward the vehicle front. A rear view mirror 4 for confirming the rear from the driver's seat 3 is supported on the lower surface of the roof panel 1 in the vehicle C.

In addition, the vehicle C is provided with a camera 11 as a window surface detection sensor for imaging the windshield 2 from inside the vehicle C and obtaining information on the surface of the windshield 2. The camera 11 includes a housing 12, a CMOS (image) sensor 13 as an image sensor housed and held in the housing 12, and a lens 14 held so as to be exposed to the outside from the housing 12. In this embodiment, the camera 11 is fixed to the roof panel 1 so as to be disposed on the vehicle front side of the rear view mirror 4. Specifically, the camera 11 has a support portion 12 a extending upward to support the housing 12, and the support portion 12 a is fixed to the roof panel 1 so that the camera 11 is disposed on the vehicle front side of the rear view mirror 4. Has been. The rear view mirror 4 is arranged at the center of the vehicle C in the vehicle width direction (width direction of the windshield 2), and the camera 11 is also arranged at the center of the vehicle C in the vehicle width direction (width direction of the windshield 2).

The imaging surface 13a of the CMOS sensor 13 and the main surface 14a of the lens 14 are on a straight line L so that a plane including the imaging surface 13a, a plane including the main surface 14a, and a plane including the outer surface 2a of the windshield 2 are aligned. It is provided at an angle so as to meet at In other words, the imaging surface 13a of the CMOS sensor 13 and the main surface 14a of the lens 14 extend non-parallel to each other. The outer surface 2a of the windshield 2 is actually curved and not a flat surface, but the inclination of the imaging surface 13a of the CMOS sensor 13 and the main surface 14a of the lens 14 is inclined using a plane closest to the curved surface. Is set. FIG. 1 is a schematic cross-sectional view of the vehicle C as viewed from the side (vehicle width direction). A plane including the imaging surface 13a is illustrated as a straight line S1, and a plane including the main surface 14a is illustrated as a straight line S2. The plane including the outer surface 2a of the windshield 2 is illustrated as a straight line S3, and the straight line L is illustrated as a point because the straight line L extends in a direction orthogonal to the paper surface.

In addition, the camera 11 has an imaging center axis J tilted in the vertical direction with respect to the horizontal plane (in other words, tilted downward toward the front of the vehicle), and the imaging center axis J has the windshield 2. The position P that intersects the outer surface 2a of the windshield 2 is provided so as to be in the range H1 of the upper half of the windshield 2. In addition, the range H1 of the upper half of the windshield 2 is a range between the upper end of the windshield 2 and the vertical direction center Z of the windshield 2 in detail.

Next, the operation of the vehicle C (camera 11) configured as described above will be described.
For example, when the lever switch SW provided in the vehicle is operated to the auto position, the windshield 2 is periodically imaged from the inside of the vehicle C by the camera 11. In FIG. 1, the imaging range (angle) by the camera 11 is indicated by a broken line. When a control unit (not shown) determines that raindrops or the like are present on the windshield 2 based on the captured image, the wiper (not shown) is driven to wipe the windshield 2 and automatically Etc. are removed.

Next, the characteristic advantages of the above embodiment will be described below.
(1) Since the camera 11 is disposed on the vehicle front side of the rear view mirror 4, it is prevented from obstructing the passenger's field of view. Further, the imaging surface 13a of the CMOS sensor 13 and the main surface 14a of the lens 14 intersect on a straight line L a plane including the imaging surface 13a, a plane including the main surface 14a, and a plane including the outer surface 2a of the windshield 2. Therefore, the focal point (focus) can be adjusted to a wide range X along the outer surface 2a of the windshield 2 by the principle of Scheinproof. In FIG. 1, the in-focus range X is schematically shown by a two-dot chain line. Therefore, even if it is arranged at a position that does not face the windshield 2 and does not interfere with the sight of the passenger, the outer surface 2a of the windshield 2 is focused and the background is not focused (background The captured image can be obtained, and the information (such as the outline of raindrops) of the outer surface 2a of the windshield 2 can be obtained with high definition in the captured image. As a result, for example, whether or not raindrops are present on the windshield 2 can be determined with high accuracy based on the captured image, and the wiper is operated more than necessary due to erroneous determination (false detection). Can be prevented.

(2) Since the support portion 12a that supports the housing 12 (the CMOS sensor 13 and the lens 14) is fixed to the roof panel 1 of the vehicle C, for example, is fixed to the inner surface of the windshield 2. As compared with the above, it is possible to image a wide range of the windshield 2.

(3) Since the camera 11 is provided so that the imaging center axis J is inclined in the vertical direction with respect to the horizontal plane, the possibility of directly capturing sunlight can be reduced. Occurrence of a phenomenon such as overexposure can be suppressed. Further, since the camera 11 is provided so that the position P where the imaging center axis J intersects the outer surface 2a of the windshield 2 is in the upper half range H1 of the windshield 2, the working distance (from the lens 14 to the windshield 2) is set. The distance to the outer surface 2a) can be shortened, and the depth of field can be reduced (shallow). Therefore, it is possible to prevent the background from being focused (focus), and thus to prevent erroneous detection.

The above embodiment may be modified as follows.
In the above embodiment, the camera 11 is fixed to the roof panel 1 so as to be arranged on the vehicle front side of the rear view mirror 4, but may be fixed to another position.

For example, as shown in FIG. 2, the camera 11 may be fixed to the inner surface 2 b of the windshield 2. That is, in this example, the support portion 12b that supports the housing 12 (the CMOS sensor 13 and the lens 14) is fixed to the inner surface 2b of the windshield 2 so that the camera 11 is disposed on the vehicle front side of the rear view mirror 4. Has been.

In this way, for example, the working distance (distance from the lens 14 to the outer surface 2a of the windshield 2) can be shortened compared to that fixed to the roof panel 1 (see the above-described embodiment). The depth of field can be reduced (shallow). Therefore, it is possible to prevent the background from being focused (focus), and thus to prevent erroneous detection.

In the above embodiment, the camera 11 is centered in the vehicle width direction (the width direction of the windshield 2) of the vehicle C and is disposed on the vehicle front side of the rear view mirror 4, but is not limited thereto. It may be fixed at another position.

For example, as shown in FIG. 3, the camera 11 may be fixed to the position of the vehicle on the driver's seat side from the center Y in the width direction of the windshield 2. That is, in this example, the support portion 12c that supports the housing 12 (CMOS sensor and lens 14) is such that the camera 11 is divided into two in the vehicle width direction in the vehicle seat side from the center Y in the width direction of the windshield 2. In the case where the steering wheel 21 is provided) is fixed to the inner peripheral surface of the windshield 2. In other words, the support portion 12c is fixed to a region of the windshield 2 between the center Y in the width direction of the windshield 2 and the width direction end of the windshield 2 near the driver's seat side door.

In this way, information on the outer surface of the windshield 2 in a range (eyepoint) corresponding to the driver's field of view can be obtained with high definition. Therefore, it is possible to determine whether or not raindrops or the like are present in a range (eye point) corresponding to the driver's field of view, and keep the driver's field of view particularly good by linking the wiper. It becomes possible.

In the above embodiment, the outer surface 2a of the windshield 2 is actually curved and not a flat surface, and the plane closest to the curved surface is used as the plane including the outer surface 2a of the windshield 2 so that the CMOS sensor 13 Although the inclination of the imaging surface 13a and the main surface 14a of the lens 14 is set, the plane including the outer surface 2a of the windshield 2 used in this way may be changed. That is, the plane including the outer surface 2a of the windshield 2 used for setting the inclination of the imaging surface 13a of the CMOS sensor 13 and the main surface 14a of the lens 14 is focused on the windshield according to the principle of Scheinproof. Other planes may be used as long as they can be adjusted to a wide range along the outer surface 2a.

For example, as shown in FIG. 4, when the windshield 2 is curved from the vertical upper end to the vertical lower end, the plane including the outer surface 2 a of the windshield 2 is the height range of the headrest 22 of the vehicle C. It is good also as a plane containing the outer surface 2a in H2. That is, in this example, the imaging surface 13a of the CMOS sensor 13 and the main surface 14a of the lens 14 are a plane including the imaging surface 13a, a plane including the main surface 14a, and an outer surface within the height range H2 of the headrest 22. It is inclined and provided so as to intersect with a plane including 2a on a straight line L. In other words, the imaging surface 13a of the CMOS sensor 13 and the main surface 14a of the lens 14 extend non-parallel to each other. FIG. 4 is a schematic cross-sectional view of the vehicle C as viewed from the side (vehicle width direction). The plane including the imaging surface 13a is illustrated as a straight line S1, and the plane including the main surface 14a is illustrated as a straight line S2. The plane including the outer surface 2a of the windshield 2 within the height range H2 of the headrest 22 is illustrated as a straight line S4. Since the straight line L extends in the direction orthogonal to the paper surface, it is illustrated with dots. The straight line S4 at this time is a tangent line having a contact A on the outer surface 2a of the windshield 2 within the height range H2 of the headrest 22.

In this way, the plane including the outer surface 2a of the windshield 2 for determining the inclination between the imaging surface 13a and the main surface 14a is the outer surface 2a within the height range H2 of the headrest 22 of the vehicle C. Since the flat surface includes the information, the information on the outer surface 2a of the windshield 2 in the height range (eye point) corresponding to the driver's field of view can be obtained with high definition. Therefore, it is possible to determine whether or not raindrops or the like are present in a range (eye point) corresponding to the driver's field of view, and keep the driver's field of view particularly good by linking the wiper. It becomes possible.

In this example, the plane including the outer surface 2a of the windshield 2 is a plane including the outer surface 2a within the height range H2 of the headrest 22 of the vehicle C. However, from the upper end to the lower end of the windshield 2 It is good also as a plane containing the outer surface 2a in the range H3 (refer FIG. 4) in the middle of the height which divided | segmented into 3 parts. Even in this case, substantially the same advantage can be obtained.

In the above embodiment, although not particularly mentioned, the image sensor (CMOS sensor 13) may be sensitive to the infrared light region. Specifically, for example, an InGaAs image sensor having sensitivity to the near infrared light region may be employed as the imaging element. If it does in this way, it will become possible to determine more precisely whether raindrop (water) exists from the phenomenon in which water absorbs infrared light. The windshield 2 has a function of cutting infrared light having a wavelength of 3000 nm or more. However, if an imaging element corresponding to the near infrared light region such as an InGaAs image sensor is used, the wavelength of 3000 nm or more is used. Even if it is used for the windshield 2 having the function of cutting infrared light, the occurrence of problems can be avoided.

In this case, a configuration may be provided that includes a filter member for preventing light in a region other than the infrared light region that is directed toward the image sensor. Specifically, for example, the filter member may include a visible light cut filter that does not transmit visible light but transmits infrared light. In this way, it is possible to determine whether or not raindrops (water) are present with higher accuracy.

In the above embodiment, although not particularly mentioned, the depth of field is preferably about 10 mm. In this way, for example, the thickness of raindrops can be detected (estimated). Further, for example, even if the mounting angle of the camera 11 is somewhat deviated, the deviation can be absorbed and a decrease in detection accuracy can be suppressed. Further, for example, it is possible to absorb the influence of the curvature of the windshield 2 (vehicle window) and suppress the decrease in detection accuracy. Of course, the depth of field may be 10 mm or more, or 10 mm or less.

In the above embodiment, the camera 11 images the windshield 2 from the inside of the vehicle C, but may capture other vehicle windows such as a rear glass.
In the above embodiment, the image sensor is the CMOS sensor 13, but is not limited to this, and may be changed to another image sensor such as a CCD (image) sensor.

In the above embodiment, the wiper is driven when it is determined that raindrops or the like are present on the windshield 2 based on the captured image, but the captured image may be used for other purposes. Further, the captured image may be used to determine whether or not insects other than raindrops are attached.

In the above embodiment, the camera 11 is simply described as including only the lens 14 exposed to the outside, but is not limited thereto, and may be a camera including a lens inside the housing 12. The lens (main surface) and the imaging surface 13a may be tilted so that the focus is adjusted to a wide range X along the outer surface 2a of the windshield 2 by the principle of Scheinproof.

Claims

A window surface detection sensor for imaging a vehicle window from the inside of the vehicle and obtaining information on the surface of the vehicle window,
An imaging device having an imaging surface;
A lens having a main surface,
The imaging surface of the imaging device and the main surface of the lens are not parallel to each other so that a plane including the imaging surface, a plane including the main surface, and a plane including the outer surface of the vehicle window intersect in a straight line. Wind surface detection sensor extending to
The window surface detection sensor according to claim 1,
A support unit for supporting the imaging element and the lens;
The support portion is a wind surface detection sensor fixed to the vehicle such that the imaging element and the lens are arranged on the vehicle front side of the rear view mirror.
The window surface detection sensor according to claim 1,
A support unit for supporting the imaging element and the lens;
The support portion is a wind surface detection sensor fixed to the vehicle such that the imaging element and the lens are disposed at a position of the vehicle closer to the driver's seat than the center of the vehicle window in the width direction.
The window surface detection sensor according to claim 2 or 3,
The said support part is a window surface detection sensor fixed to the inner surface of the said vehicle window.
The window surface detection sensor according to claim 2 or 3,
The support portion is a wind surface detection sensor fixed to a vehicle roof panel.
The window surface detection sensor according to any one of claims 1 to 5,
The window surface detection so that the imaging center axis is inclined in the vertical direction with respect to the horizontal plane, and the position where the imaging center axis intersects the outer surface of the vehicle window is within the upper half of the vehicle window. A window surface detection sensor provided with a sensor.
The window surface detection sensor according to any one of claims 1 to 6,
The image sensor is a window surface detection sensor having sensitivity to an infrared light region.
The window surface detection sensor according to claim 7,
A window surface detection sensor further comprising a filter member for preventing transmission of light in a region other than the infrared light region toward the image sensor.
The window surface detection sensor according to any one of claims 1 to 8,
The vehicle window is curved from the vertical upper end to the vertical lower end,
The plane including the outer surface of the vehicle window is a window surface detection sensor which is a plane including the outer surface within the height range of the headrest of the vehicle.