WO2022230287A1

WO2022230287A1 - On-board camera device

Info

Publication number: WO2022230287A1
Application number: PCT/JP2022/004473
Authority: WO
Inventors: 武志芳賀; 陽一有路
Original assignee: 日立Astemo株式会社
Priority date: 2021-04-28
Filing date: 2022-02-04
Publication date: 2022-11-03
Also published as: JPWO2022230287A1; DE112022001196T5

Abstract

Provided is a on-board camera device that can prevent reflection of reflected light without increasing the overall device size, even if the visual field of a stereo camera is made wide angle in a left-right direction, and that can also suppress fogging in front of a lens. This on-board camera device includes: a plurality of cameras that each comprise an imaging element and a lens system; a polarizing filter attached to each of the plurality of cameras; a camera cover that stores the plurality of cameras; and a hood that extends in the visual field direction of the plurality of cameras. The hood is a member that is common to the plurality of cameras and that includes a single flat section extending in the visual field direction of the plurality of cameras.

Description

In-vehicle camera device

The present invention relates to an in-vehicle camera device mounted on the inner surface of the windshield.

In recent years, vehicles such as automobiles have advanced driving support systems that activate driver support controls such as emergency automatic braking and steering operation support according to the external environment, and automated driving systems that control all steering and acceleration/deceleration. As a type of sensor for realizing each system, there is a stereo camera mounted on the upper inner surface of the windshield for imaging the front.

A stereo camera identifies the horizontal deviation (parallax) of the same object in a pair of images captured by the left and right cameras, and uses the principle of triangulation based on the identified parallax to determine the distance to the object. It has the ability to measure distance. The stereo camera also has a function of determining whether each object is a vehicle, a pedestrian, or something else, based on the shape and size of each captured object.

A structure described in Patent Document 1 is known as a structure for fixing a stereo camera to a windshield. For example, in the abstract of the document, it is stated that "in the in-vehicle imaging device 100, an imaging unit that captures an image, a shielding unit that shields a part of the imaging unit, a holding unit that holds the imaging unit, wherein a holding portion is adhered to a window glass in advance, the imaging portion has a supported portion supported by the holding portion, and the holding portion is arranged in a direction in which the imaging portion approaches the shielding portion. a guide portion that guides the supported portion in a certain first direction; and a guide portion that restricts movement of the supported portion in the first direction after being guided by the guide portion and supports the supported portion. It is characterized by having a support part."

Here, if there is a gap between the window glass (windshield) and the in-vehicle imaging device (stereo camera), the light from below will be reflected by the windshield and enter the camera lens, degrading the image quality of the captured image. It may deteriorate.

Therefore, in Patent Document 1, in paragraph 0020 of the same document, "the vehicle-mounted camera 11 has two camera units 22 capable of imaging through the lens 21. The camera units 22 are CCD (Charge Coupled Device) and CMOS (Complementary Metal Oxide Semiconductor), which is not shown, and performs imaging through the hollow portions of the lens 21 and the lens hood 33, as shown in Fig. 1. Further, as shown in Fig. 2, the lens hood 33 can prevent light outside the imaging range 16 from entering the camera section 22.", the surroundings of the imaging angle of view range are covered with a shielding section (lens hood 33), and light outside the imaging range is covered. of light is prevented from entering the camera unit, the image quality deterioration of the captured image is suppressed (see also FIGS. 1 and 2 of the same document).

Japanese Unexamined Patent Application Publication No. 2020-114728

Advanced driver assistance systems and automated driving systems in recent years are required to have more advanced functions, such as detecting pedestrians crossing the road when turning right or left at an intersection and activating automatic emergency braking. As a proposal to meet this demand, the field of view of stereo cameras is being widened.

However, in order to apply a structure in which the periphery of the imaging angle of view is covered with a shielding part as shown in FIG. Therefore, it is necessary to expand the range of the shielding part in the horizontal direction. In that case, the expanded shielding part blocks the driver's field of vision, and depending on the type of vehicle, there is a possibility that it may violate the field of vision regulation. In addition, as in Patent Document 1, if the entire periphery of the imaging angle of view is covered with a shield, the flow of air between the windshield and the lens becomes poor, and fogging tends to occur. Therefore, in some cases, it was necessary to take measures such as incorporating an anti-fogging heater at the bottom of the shield.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points. To provide an in-vehicle camera device capable of preventing fogging and suppressing the occurrence of fogging in front of the lens.

In order to solve the above-mentioned problems, an in-vehicle camera device of the present invention includes a plurality of cameras each comprising an imaging element and a lens system, a polarizing filter attached to each of the plurality of cameras, and a camera cover housing the plurality of cameras. and a canopy extending in the direction of the field of view of the plurality of cameras, wherein the canopy is common to the plurality of cameras and is a member including a single planar portion extending in the direction of the field of view of the plurality of cameras. and

The in-vehicle camera device of the present invention can prevent reflection of reflected light and prevent fogging in front of the lens even when the field of view of the stereo camera is widened in the horizontal direction without increasing the size of the entire device. can do.

Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiment.

1 is a perspective view of a stereo camera device of one embodiment; FIG. FIG. 1 is a side view showing a stereo camera device in an on-vehicle state of an embodiment; FIG. 4 is a top view for explaining the shape of the eaves of the stereo camera device of the embodiment (when θ is small); FIG. 4 is a perspective view explaining the structure of a camera cover used in a comparative example; The side view which shows the vehicle-mounted state of the stereo camera of a comparative example. FIG. 4 is a top view for explaining a modification of the eaves of FIG. 3 (when θ is large);

A stereo camera device 1, which is an embodiment of the vehicle-mounted camera device of the present invention, will be described below with reference to the drawings.

FIG. 1 is a perspective view of the stereo camera device 1 of this embodiment. As shown here, the stereo camera device 1 of this embodiment is an in-vehicle camera device having a left camera 10L, a right camera 10R, an image processing section 20, a camera cover 30, and an eaves 31. FIG. FIG. 2 is a side view showing a state in which the stereo camera device 1 of this embodiment is mounted on the upper inner surface of the windshield 2. As shown in FIG. In addition, below, as shown in FIG. 2, the inclination angle which the windshield 2 makes with horizontal is defined as (theta).

The left camera 10L and the right camera 10R are a pair of imaging devices arranged side by side so as to capture an image in front of the vehicle on which the stereo camera device 1 is mounted. 10R captures the right captured image PR. Details of both cameras will be described later.

The image processing unit 20 processes the left captured image PL and the right captured image PR (hereinafter also referred to as “captured image P”) to determine the environment outside the vehicle (for example, the position and speed of other vehicles, the position and speed of pedestrians, After detecting the position of white lines on the road surface, the type of road signs, etc.), it outputs the detected external environment information to the ECU (Electronic Control Unit) etc. via the controller area network CAN. The image processing unit 20 is specifically a computer equipped with hardware such as an arithmetic device such as a microcomputer, a storage device such as a semiconductor memory, and a communication device. is executed to detect the environment outside the vehicle, but the following description will be made while omitting such well-known techniques as appropriate.

The camera cover 30 is a resin protective cover that covers the left camera 10L, the right camera 10R, and the image processing section 20. The canopy 31 is a flat plate made of resin extending from the lower front surface of the camera cover 30 to a position in contact with or very close to the windshield 2, and extends in the front-rear direction so as not to block the field of view of the left camera 10L and the right camera 10R. A tilt angle is set (see FIG. 2). Incidentally, the camera cover 30 and the eaves 31 may be formed integrally, or may have a structure in which separate bodies are joined together with screws or the like.

As shown in FIGS. 1 and 2, the upper surface of the eaves 31 is flat so as not to obstruct the airflow in the left-right direction, and the air is less likely to stay in the space sandwiched between the windshield 2 and the eaves 31. It is designed to prevent fogging.

Next, the structure of the left camera 10L and the right camera 10R, the relationship between the fields of view of each camera, and the shape of the eaves 31 will be described using the top view of FIG. Note that the illustration of the image processing unit 20 is omitted here.

As shown here, the left camera 10L includes an imaging element 11L such as a CCD or CMOS, a lens 12L for focusing on the imaging element 11L, and a polarizing filter 13L for preventing transmission of reflected light incident from the front direction. have. Similarly, the right camera 10R has an imaging element 11R such as a CCD or CMOS, a lens 12R for focusing on the imaging element 11R, and a polarizing filter 13R for preventing transmission of reflected light incident from the front direction. there is

In this embodiment, the imaging device 11L of the left camera 10L is arranged on the left side, and the lens 12L is arranged on the right side, so that the field of view of the left camera 10L indicated by the dashed line is tilted to the right from the front. Symmetrically, the imaging device 11R of the right camera 10R is arranged on the right side, and the lens 12R is arranged on the left side, so that the field of view of the right camera 10R indicated by the dashed line is tilted leftward from the front.

In this way, the front direction of the stereo camera device 1 is the common field of view of the left camera 10L and the right camera 10R, the right direction is the monocular field of view of the left camera 10L, and the left direction is the monocular field of view of the right camera 10R. The stereo camera device 1 of this embodiment realizes widening of the field of view in the left-right direction while using an imaging element equivalent to that of the conventional one.

<Influence of Reflected Light in Stereo Camera Device 1A of Comparative Example>
Here, the problem of reflected light that occurs in the stereo camera device 1A of the comparative example that does not have the canopy 31 will be described with reference to FIGS. 4 and 5. FIG. FIG. 4 is a perspective view of a camera cover 30A used in the stereo camera device 1A of the comparative example, and FIG. . Note that the stereo camera device 1A of the comparative example is the same as the stereo camera device 1 of the present embodiment except for one point that it does not have the eaves 31 (see FIG. 4). A wide angle in the horizontal direction is realized by intentionally providing a single viewing area (see FIG. 3).

As illustrated by the solid line arrows in FIG. 5, in the stereo camera device 1A of the comparative example that does not have the eaves 31, the light from below within the range sandwiched by the dashed lines in FIG. The light is reflected by the windshield 2 and enters the left camera 10L and the right camera 10R.

Of the reflected light incident on the left camera 10L, the reflected light with a small incident angle (see FIG. 3) incident from the common viewing direction can be removed by the polarizing filter 13L designed to remove the reflected light in the front direction. , reflected light with a large incident angle that enters from the left camera monocular viewing direction cannot be removed by the directional polarizing filter 13L, so there is a high possibility that the reflected light will be captured in the monocular viewing area of the left captured image PL.

Similarly, of the reflected light incident on the right camera 10R, the reflected light with a small incident angle from the common viewing direction can be removed by the polarizing filter 13R designed to remove the reflected light in the front direction. Reflected light with a large incident angle entering from the direction of the monocular field of view of the camera cannot be removed by the directional polarizing filter 13R.

As described above, the stereo camera device 1A of the comparative example without the canopy 31 has a problem that the image quality of the monocular visual field region of the captured image P deteriorates due to the influence of the reflected light that cannot be removed by the

polarizing filters

13L and 13R.

<Influence of reflected light in the stereo camera device 1 of the present embodiment>
On the other hand, in the stereo camera device 1 of the present embodiment, as shown in FIGS. 2 and 3, the camera cover 30 is placed below the monocular visual field direction of the left camera 10L so as to contact or come very close to the windshield 2 from the lower front surface of the camera cover 30. 5. Since the substantially trapezoidal canopy 31 is provided, which extends to a position where the front side (upper side) is narrow and the rear side (bottom side) is wide, the reflected light as indicated by the solid line arrow in FIG. The light does not enter the left camera 10L, and image quality deterioration of the left captured image PL due to the influence of reflected light is avoided. A similar action avoids image quality deterioration of the right captured image PR due to the influence of reflected light.

<Modified example of eaves 31>
Next, a modification of the canopy 31 of FIG. 3 will be described with reference to FIG.

The canopy 31 illustrated in FIG. 3 has a shape assuming a vehicle such as a sedan-type passenger car in which the inclination angle θ of the windshield 2 is relatively small. In addition, it was possible to prevent the incidence of reflected light even in the common viewing direction in which the light can be removed.

On the other hand, the eaves 31 illustrated in FIG. From the right and left of , it has the structure which the reflected light of the windshield 2 can pass through. However, since the reflected light from the common visual field direction that has passed through the left and right sides of the front side of the eaves 31 can be removed by the polarizing filter 13 having the property of removing the reflected light from the front direction, the left captured image PL and the right captured image Image quality deterioration due to the influence of reflected light can be suppressed for the PR common viewing area.

Also, in the stereo camera device 1 illustrated in FIG. 6, since the canopy 31 is always arranged below the direction of the left camera single visual field or the right camera single visual field, the single visual field area where the polarizing filter 13 cannot remove the reflected light. As for the above, the canopy 31 can prevent the reflected light from entering, and the deterioration of the image quality of the left captured image PL and the right captured image PR can be suppressed.

In order to obtain the effects of the present invention described above, the eaves 31 should be designed so as to satisfy all of the following conditions, as is clear from FIGS. (1) When the stereo camera device 1 is mounted, the front side of the canopy 31 is in contact with or very close to the windshield 2 . (2) The canopy 31 is below the field of view of the left camera 10L and the right camera 10R. (3) The right edge of the front side of the canopy 31 is on the right side of the right edge of the field of view of the left camera 10L. (4) The left edge of the front side of the canopy 31 is on the left side of the left edge of the field of view of the right camera 10R.

With the stereo camera device 1 of this embodiment that satisfies these conditions, even if the canopy 31 is made small in order to secure the driver's field of view, the captured image P is affected by the reflected light from a single visual field direction. Deterioration can be suppressed, and the occurrence of fogging in front of the lens can be suppressed.

As described above, with the in-vehicle camera device of the present invention, even when the field of view of the stereo camera consisting of the left and right cameras is widened in the horizontal direction, reflection of reflected light can be prevented without increasing the size of the entire device. It is possible to suppress the occurrence of fogging in the front.

REFERENCE SIGNS LIST 1, 1A... stereo camera device, 10L... left camera, 10R... right camera, 11... imaging device, 12... lens, 13... polarizing filter, 20... image processing unit, 30, 30A... camera cover, 31... canopy, 2 …windshield

Claims

a plurality of cameras each comprising an imaging element and a lens system; a polarizing filter attached to each of the plurality of cameras; a camera cover housing the plurality of cameras; death,
An in-vehicle camera device, wherein the canopy is common to the plurality of cameras and is a member including a single plane portion extending in a viewing direction of the plurality of cameras.
The in-vehicle camera device according to claim 1,
The plurality of cameras are stereo cameras consisting of a right camera and a left camera,
imaging the left side with respect to the central axis of the stereo camera with the right camera;
imaging the right side with respect to the central axis of the stereo camera with the left camera; and
a portion of the field of view of the right camera and the left camera overlap so that the camera has a monocular field of view and a stereo field of view;
The eaves have a base side that is in contact with the camera cover and a top side that faces the bottom side. , a vehicle-mounted camera device having a shape that is longer than the distance between the position of the upper side and the right end of the field of view of the left camera.
The in-vehicle camera device according to claim 1,
An in-vehicle camera device, wherein the eave does not have a side wall extending in a substantially vertical direction with respect to the single plane portion.
In the in-vehicle camera device according to claim 2,
The in-vehicle camera device, wherein the eaves are provided at least at a position corresponding to the monocular visual field range.
The in-vehicle camera device according to claim 1,
The single planar portion comprises:
An in-vehicle camera device, wherein the camera cover has a trapezoidal shape with a front side coming in contact with or very close to a windshield when the camera cover is in-vehicle, and a flat upper surface.
In the in-vehicle camera device according to claim 5,
a left camera whose viewing direction is tilted to the right;
a right camera with a viewing direction tilted to the left;
The image captured by the left camera is classified into a left camera monocular viewing area and a common viewing area,
The image captured by the right camera is classified into a right camera monocular viewing area and a common viewing area,
An in-vehicle camera device, wherein reflected light from the windshield is not imaged in the left camera monocular visual field area and the right camera monocular visual field area.
In the in-vehicle camera device according to claim 5,
a left camera whose viewing direction is tilted to the right;
a right camera with a viewing direction tilted to the left;
The right edge of the front side of the eaves is on the right side of the right edge of the field of view of the left camera,
An in-vehicle camera device, wherein the left end of the front side of the eaves is on the left side of the left end of the visual field of the right camera.