WO2021075179A1 - In-vehicle camera system, vehicle, and polarizing element - Google Patents

Abstract

This in-vehicle camera system for photographing the outside world from the inside of a vehicle comprises a camera that includes an image sensor element for converting an optical signal into an electrical signal and a lens for forming an image of light, and a polarizing element that is provided on the front side of the lens, wherein in the polarizing element, a polarization direction of light passing through the polarizing element changes according to at least one of the incident angle or the incident position of the light.

Description

On-board camera systems, vehicles, and polarizing elements Capture by reference

This application claims the priority of Japanese Patent Application No. 2019-188354, which is a Japanese application filed on October 15, 2019, and incorporates it into this application by referring to its contents.

The present invention relates to an in-vehicle camera system.

As a background technology in this technical field, there is Japanese Patent Application Laid-Open No. 11-787737. In this reference, there is a description about the arrangement of the windshield, the camera and the polarizing filter to prevent the dashboard from being reflected on the front glass etc. and reflected in the camera image. In a vehicle-mounted camera for photographing the environment, the camera is mounted on the inner surface of the front windshield of the vehicle, and a polarizing filter is arranged in front of the lens of the vehicle-mounted camera. This eliminates the need for a stay mounting portion. The vibration resistance is improved, the image quality is improved, it is easy to deal with each vehicle type, and it is possible to effectively prevent the dashboard and the like from being reflected on the front windshield. " (See paragraph [0006]).

There is also Japanese Patent Application Laid-Open No. 2001-94842. In this publication, there is a description corresponding to the reflected light other than the horizontal direction caused by the formation of a curvature in the left-right direction of the windshield of an automobile. It is used in an image recognition device that monitors the running state by recognition, and a polarizing filter is attached to the front of the camera, and the polarization axis of this polarizing filter is set to an offset angle determined according to the curvature of the windshield in the vertical direction. It was decided to have it. "(See paragraph [0016]).

Further, there is Japanese Patent Application Laid-Open No. 2013-31051. In this publication, even when the polarizing filter is used for the purpose of selectively transmitting only the reflected light (polarized light) from the curved surface by the polarizing filter, the polarization axis (transmission axis) is uniform over the entire filter surface. The conventional polarizing filter has a problem that only the reflected light (polarized light) from a part of the curved surface can be sufficiently transmitted, and the transmittance of the reflected light (polarized light) from the remaining part is insufficient. There is a description, "via a polarizing filter provided with a polarizing filter region which is installed so that the relative position with respect to the curved surface member having a curved surface is constant and which cuts or selectively transmits the reflected light from the curved surface. In an imaging apparatus that images the inside of an imaging region by receiving light from an object existing in the imaging region by an image sensor composed of a pixel array in which light receiving elements are two-dimensionally arranged, the polarizing filter region is described above. Is composed of a plurality of filter region portions having different transmission axis directions, and the transmission axis direction of each filter region portion is the reflected light from the curved surface of the curved surface member incident on the filter region portion. An imaging device characterized in that it is set based on the polarization direction of the maximum polarization component. ”(See claim 1).

In the in-vehicle camera system, the camera captures the scenery of the outside world and the object as an image, the image processing system in the subsequent stage detects and recognizes the object, and controls the vehicle using the recognition result. In-vehicle cameras are often installed inside the vehicle to avoid the risk of foreign matter such as raindrops and mud adhering to the lens, and as a result, reflections on the glass in front of the camera cause reflections in the interior such as the dashboard. It may reduce the detection / recognition performance of objects. As a countermeasure for this, a method of reducing reflected light by using a polarizing filter as in Patent Document 1 has been proposed.

In this reflected wave reduction method, in a situation where the S polarization of many reflected lights is in the horizontal direction, the intensity of the reflected light is reduced by making the polarization direction of the light passing through the polarizing filter vertical. However, the reflector in front of the camera, such as a windshield, often has a curved surface shape, and the polarization direction may not be symmetrical with respect to the optical axis of the camera. Therefore, as in Patent Document 2, a method is disclosed in which the polarization direction of the passing light is appropriately tilted from the vertical direction to cope with the left-right tilt of the reflecting object.

However, with the recent widening of the angle of in-vehicle cameras, reflected light is incident from a wide angle, and the direction of S polarization differs depending on the incident direction and is not a constant direction. Therefore, even if a conventional polarizing element having a constant polarization direction is used, it has become difficult to sufficiently reduce the reflection in a wide range. Therefore, as in Patent Document 3, a method using a filter having a plurality of polarization directions on the same plane has been proposed.

However, forming different polarization directions on the same plane of the polarizing filter is expensive because the manufacturing method is complicated as compared with generating a uniform polarization direction. Further, the finer or more complicated the change in the polarization direction, the more difficult the manufacturing becomes.

A typical example of the invention disclosed in the present application is as follows. That is, an in-vehicle camera system that photographs the outside world from the inside of a vehicle, the camera including an image sensor that converts an optical signal into an electric signal and a lens that forms an image of light, and a polarizing element provided on the front side of the lens. The polarizing element is characterized in that the polarization direction of the light passing through the polarizing element changes according to at least one of the incident angle or the incident position of the light.

According to the present invention, reflection can be reduced in a wide field of view. Issues, configurations and effects other than those mentioned above will be clarified by the description of the following examples.

It is a figure which shows the reflection in the narrow angle of view in-vehicle camera system. It is a figure which shows the polarization element which reduces the S polarization in a horizontal direction. It is a figure which shows the reflection in the wide angle of view in-vehicle camera system. It is a figure which shows the polarization element which reduces the S polarization in an oblique direction. It is a figure which shows the configuration example of the vehicle-mounted camera system of Example 1 and the vehicle which has this. It is a figure which shows the example of the film-like polarizing element formed in a tubular shape. It is a figure which shows the principle of the reflected light reduction by the three-dimensional shape polarizing element. It is a figure which shows another example of the film-like polarizing element formed in a tubular shape. It is a figure which shows another example of the film-like polarizing element formed in a tubular shape. It is a figure which shows another example of the film-like polarizing element formed in a tubular shape. It is a figure which shows the example of the film-like polarizing element formed in a truncated cone. It is a figure which shows the example of the film-like polarizing element formed as a part of a rotating body. It is a figure which shows the configuration example of the vehicle-mounted camera system using the polarizing element shown in FIG. 8 and the vehicle which has this. It is a block diagram of the vehicle-mounted camera system of the first embodiment. It is a figure which shows the example of the attenuation polarization direction of a plate-like polarizing element when the inclination of a windshield is 25 degrees. It is a figure which shows the example of the attenuation polarization direction of a plate-like polarizing element when the inclination of a windshield is 45 degrees. It is a figure which shows the example of the attenuation polarization direction of a plate-like polarizing element when the inclination of a windshield is 60 degrees. It is a figure which shows the example of the attenuation polarization direction of a plate-like polarizing element when the inclination of a windshield is 90 degrees. It is a figure which shows the configuration example of the vehicle-mounted camera system of Example 2 and the vehicle which has this. It is a figure which shows another configuration example of the vehicle-mounted camera system of Example 2.

Hereinafter, an example of an in-vehicle camera system having a polarizing element for reducing reflection in the vehicle interior and improving the performance of object detection and object recognition and a vehicle equipped with the same will be described with reference to the drawings.

First, the necessity of the present invention will be described with reference to FIG. FIG. 1 shows the periphery of the windshield of a vehicle having the vehicle-mounted camera system 200. The windshield 300 is provided on the upper part of the dashboard 310 of the vehicle, and the vehicle-mounted camera system 200 is provided on the upper part of the windshield 300. In the figure, the arrow a indicates the traveling direction of the vehicle. Arrows b, c, and d indicate light rays emitted from the dashboard 310 or the like, reflected by the windshield 300, and incident on the camera, that is, light rays related to so-called reflection. When the angle of view of the camera is small, light rays related to reflection on the dashboard or the like are incident from below, and the S polarization component of the light reflected by the windshield 300 is in the horizontal direction. Therefore, as shown in FIG. 2, most of the reflected light can be reduced by installing the polarizing element 100 in which the polarization direction of the passing light is the vertical direction in the lens barrel 210 of the camera system.

On the other hand, when the angle of view of the camera is widened, as shown in FIG. 3, the light ray c'd'related to the reflection is incident from diagonally downward. At this time, for example, the polarization direction of the light passing through the polarizing filter for reducing the reflected light of c'needs to be directed obliquely as shown in FIG. However, with respect to the reflected light b, the polarization direction of the passing light must be directed perpendicularly as described above. As described above, with a plate-shaped filter such as a conventional polarizing filter in which the polarization direction of the passing light is constant, it is difficult to reduce the light rays related to the reflection incident from various directions.

<Example 1>
An example of an in-vehicle camera system 200 and a vehicle having the in-vehicle camera system 200 that solves the above problems will be described. FIG. 5 is a diagram showing a configuration example of the in-vehicle camera system 200 of this embodiment and a vehicle provided with the in-vehicle camera system 200. FIG. 5 schematically shows a cross section of a vehicle (not shown) cut to the left and right. In the first embodiment, the reflection is reduced and the object is reduced by continuously changing the polarization direction of the light passing through the polarizing element 100 according to the incident angle of the light incident on the polarizing element 100 having a three-dimensional shape. An example of an in-vehicle camera system 200 that improves detection and object recognition performance and a vehicle having the same will be described.

The in-vehicle camera system 200 is fixed to the windshield 300 by a support (not shown). Further, the in-vehicle camera system 200 outputs vehicle control information by a data communication means (not shown), and the vehicle information is input. The in-vehicle camera system 200 has a polarizing element 100 on the front side thereof. The polarizing element 100 is formed by bending a polarizing film into a curved surface as shown in FIG. 6 to form a tubular shape, and the polarization direction of the passing light is the same as the rotation axis of the cylinder as shown by the solid line arrow in FIG. Moreover, it is installed so as to be substantially parallel to the normal line of the front glass 300. An in-vehicle camera system 200 is installed in one opening of the tubular polarizing element, and all camera images are imaged by light rays that have passed through the polarizing element 100. The other opening is supported by the bracket 400 and is closed to prevent outside light from entering through the opening, and the bracket 400 serves as a shielding member for preventing the reflected light on the inner surface of the polarizing element 100 from entering the camera. It is functioning.

FIG. 7 is a diagram showing a principle in which this embodiment uses a three-dimensionally shaped polarizing element to reduce reflected light incident from multiple directions. In the figure, the cylindrical polarizing element 100 is arranged on the reflecting surface 300 of a flat plate assuming a windshield. Further, the figure shows S-polarized light e and f of the reflected light in the polarizing element 100. The axis of rotation (indicated by an arrow) of the polarizing element 100 is parallel to the normal of the reflecting surface 300, and the polarization direction of the light passing through the polarizing element 100 is also parallel to the normal of the reflecting surface 300. The S-polarized light e and f of the reflected light reflected by the reflecting surface 300 and traveling toward the central axis of the polarizing element are perpendicular to the traveling direction and parallel to the reflecting surface 300. Therefore, since the S-polarized light e and f are perpendicular to the polarization direction of the light passing through the polarizing element 100, the reflected light appears to be reduced to the camera placed in the cylinder of the polarizing element. In FIG. 5 described above, the reflected light can be reduced by the same principle. That is, the polarization direction of the light passing through the polarizing element 100 is irrelevant to the positional relationship with the camera, and is determined by the relationship with the normal of a reflector such as a windshield. The inclination of the windshield differs depending on the vehicle, and trucks and buses have a nearly vertical inclination of about 90 degrees, and some passenger cars have a small inclination angle such as 10 degrees. When the polarization direction of the light passing through the polarizing element 100 is 90 degrees (parallel to the normal line) with respect to the inclination angle α of the reflecting surface, the reflected light can be effectively reduced. When this is expressed with reference to the optical axis of the camera, when the optical axis is oriented in the horizontal direction, the reflected light can be effectively reduced at 90-α degrees (for example, 0 to 80 degrees). This angle may be based on the lens barrel axis instead of the optical axis of the camera. In addition, α is an arbitrary positive number.

Further, in FIG. 5, the optical axis of the in-vehicle camera system 200 is represented by a one-dot chain line, and the vertical angle of view of the in-vehicle camera system 200 is represented by a broken line. The upper edge of the angle of view (shooting range) passes below the boundary of the bracket-side opening of the tubular polarizing element 100, and is designed so that the boundary of the polarizing element is not reflected in the camera image. In other words, when the three-dimensional polarizing element 100 described above is formed from a flat polarizing filter, the opening may be arranged at a position not within the camera angle of view. Further, the connection portion when the flat plate polarizing filter is rolled and the end portion of the polarizing element 100 in the form described later (FIGS. 8, 9, and 10) may be arranged at a position not within the camera angle of view, for example, at the upper part. ..

FIG. 14 is a block diagram of a configuration example of the in-vehicle camera system 200 of this embodiment. The in-vehicle camera system 200 includes a camera module 201 including a lens and an image sensor, an image correction unit 203, an object recognition unit 204, and a parameter memory 205. The camera module 201 sends the captured image data to the image correction unit 203. The image correction unit 203 corrects the brightness and distortion of the image data input from the camera module 201 based on the parameters read from the parameter memory 205, and sends the corrected image data to the object recognition unit 204. The object recognition unit 204 recognizes an object from the corrected image data, generates a control signal based on the recognition result, and sends the generated control signal to a vehicle control unit (for example, an automatic driving ECU).

As described above, the cylindrical polarizing element 100 is installed with the rotation axis of the cylinder and the polarization direction of the passing light parallel to the normal line of the front glass 300, and the camera module 201 is installed in one opening and the other opening is installed. By providing the light-shielding structure (bracket 400) in the light-shielding structure, the polarization direction of the light passing through the polarizing element 100 can be continuously changed according to the incident angle of the light incident on the polarizing element 100. Therefore, it is possible to take an image with reduced reflection over a wide range, and it is possible to improve the performance of object detection and object recognition.

The polarizing element 100 of this embodiment is not limited to the shape described above in FIG. 6, and may form, for example, a part of the side surface of the pillar as shown in FIGS. 8, 9, and 10. Specifically, the polarizing element 100 shown in FIG. 8 has a shape in which a film-shaped polarizing plate is formed in a tubular shape, both openings are obliquely cut off, and the side surface of the cylinder is not closed at the upper portion. Further, the polarizing element 100 shown in FIG. 9 has a shape in which a film-shaped polarizing plate is formed in a tubular shape, an opening on the camera side is cut diagonally, and an upper portion of a side surface is cut in parallel with a shaft. Further, the polarizing element 100 shown in FIG. 10 has a shape in which a film-shaped polarizing plate is formed in a tubular shape, the opening on the camera side is cut diagonally, and the upper part of the side surface is cut larger than in FIG. 9 in parallel with the axis. Is. As described above, the same effect can be obtained even in a shape in which the upper polarizing film from which the reflected light is not incident is removed. Further, the polarizing element 100 may have a shape in which the diameter on the vehicle-mounted camera system 200 side is smaller than that on the windshield 300 side. That is, as shown in FIG. 11, a shape may form a part of the truncated cone, or a shape having a small diameter of one opening as shown in FIG. 12 in order to correspond to a curved surface in the left-right direction of the windshield 300. Good. However, even in such a case, it is desirable that the opening is covered with a camera, a bracket 400, or the like so that reflection does not occur on the inner surface of the polarizing element 100. FIG. 13 shows the positional relationship between the windshield 300, the bracket 400, and the in-vehicle camera system 200 when the polarizing element 100 having the shape shown in FIG. 8 is used. The bracket 400 has a shape that shields the opening of the polarizing element 100 on the windshield side from light.

Further, in the present embodiment, the polarization direction of the light passing through the polarizing element 100 is parallel to the normal line of the windshield 300, but the present invention is not limited to this. That is, as described above, the polarizing element 100 may be formed so that the rotation axis of the cylindrical or conical polarizing element 100 and the polarization direction are parallel to each other, but the rotation axis of the polarizing element 100 The polarizing element 100 may be formed so that the polarization direction has a predetermined angle. The effect of reducing reflected light can be obtained even if the polarization direction is not parallel to the rotation axis. For example, for a vehicle with an inclination of the windshield 300 of 30 degrees and a vehicle with an inclination of the windshield 300 of 40 degrees, the angle between the rotation axis of the polarizing element 100 and the optical axis of the camera may be 55 degrees, or the polarizing element 100 may be set. Even if the in-vehicle camera system 200 in which the angle between the polarization direction of the light passing through the windshield and the optical axis of the camera is 55 degrees is applied, a certain effect can be obtained. Further, the polarizing element 100 may be formed with a curved line so that the rotation axis of the cylindrical or conical polarizing element 100 is a straight line parallel to the polarization direction, but the rotation axis of the cylindrical or conical polarizing element 100. The polarizing element 100 may be formed with a curved surface so that the polarization direction becomes a curved line having a predetermined angle.

Further, in the present embodiment, the in-vehicle camera system 200 is supported by the windshield 300 via a support (not shown), but the present invention is not limited to this. The same effect can be obtained even if the in-vehicle camera system 200 is supported by the roof.

Further, in the present embodiment, the reflector in front of the camera is the windshield 300, but the present invention is not limited to this. The rear glass is used as a reflector for a camera that shoots the rear, and the side glass is used as a reflector for a camera that shoots in the lateral direction. In this case, the same effect can be obtained.

The same effect can be obtained even when the camera system is a stereo camera. However, when the in-vehicle camera system 200 is a stereo camera, the rotation axis of the polarizing element of the right camera is on the upper right, considering that the front glass 300 in front of each of the left and right cameras is inclined in the left-right direction. It is desirable that the rotation axis of the polarizing element of the left camera is directed to the upper left.

Furthermore, in order to reduce image distortion, it is desirable to reduce the thickness of the polarizing element. For example, it is desirable to use a general-purpose polarizing film having a thickness of about 0.1 to 0.2 mm.

Further, in the calibration process for adjusting the distortion and brightness of the captured image before shipment, it is desirable to perform the adjustment by combining the camera module 201 with a polarizing element from the viewpoint of adjustment accuracy. On the other hand, if there is a limitation in the process order, the brightness may be adjusted by the camera module alone, and the image distortion may be adjusted after combining the polarizing elements. Further, instead of the adjustment performed by the camera module 201 alone, the adjustment may be performed by using a polarizing element for adjustment.

<Example 2>
In the first embodiment, by forming the polarizing element into a three-dimensional shape, the polarization direction of the light passing through the polarizing element is continuously changed according to the incident angle of the light on the polarizing element. When the lens of the camera is a wide-angle lens, the incident light rays include those that do not form an image on the imaging device, and the light rays incident from a specific direction at a specific position on the plane perpendicular to the optical axis. Only the light rays passing through the lens contribute to the imaging. Therefore, the plate-shaped polarizing element is used to continuously change the polarization direction of the light passing through the polarizing element according to the incident position of the light on the polarizing element. In the second embodiment, the reflection is reduced by continuously changing the polarization direction of the light passing through the polarizing element 100 according to the incident position of the light on the planar polarizing element 100, and the object detection and the object are detected. An example of an in-vehicle camera system 200 for improving recognition performance and a vehicle having the same will be described.

Note that, in the second embodiment, the description of the configuration having the same function as that of the first embodiment will be omitted, and different configurations will be mainly described.

FIG. 15 is a diagram showing a planar polarizing element 150. The dotted line in the figure indicates the polarization direction of the light attenuated by reflection or absorption (hereinafter referred to as the attenuated polarization direction) which is orthogonal to the polarization direction of the light passing through the polarizing element 100 among the polarization directions. The decaying polarization direction is indicated by a quadratic function curve or an ellipse, and the upper side of the polarizing element 150 is a downwardly convex curve, the lower side is flatter, and the lower side is an upwardly convex curve.

This curve differs depending on the relative angle between the normal of the polarizing element 150 and the inclination of the windshield 300 which is a reflector. When the optical axis of the camera and the normal of the polarizing element 150 are in the horizontal direction, FIG. 15 shows a curve in the decaying polarization direction when the inclination of the front glass 300 is 25 degrees, and FIG. 16 shows a curve of the attenuation polarization direction when the inclination of the front glass 300 is 45 degrees. The curve of the dampening polarization direction in the case of degrees is shown, FIG. 17 shows the curve of the dampening polarization direction when the inclination of the front glass 300 is 60 degrees, and FIG. 18 shows the curve of the dampening polarization direction when the inclination of the front glass 300 is 90 degrees. The curve of the direction is shown.

FIG. 19 is a diagram showing a configuration example of the in-vehicle camera system 200 of this embodiment and a vehicle equipped with the in-vehicle camera system 200. In FIG. 19, the vehicle-mounted camera system 200 is fixed to the windshield 300 by a support (not shown). Further, the in-vehicle camera system 200 outputs vehicle control information by a data communication means (not shown), and the vehicle information is input. The in-vehicle camera system 200 has a polarizing element 150 on the front side thereof, and the polarizing element 150 is supported by the in-vehicle camera system 200.

As described above, in the planar polarizing element 150, the polarization direction is changed depending on the position on the plane, and in particular, the decaying polarization direction is formed into a curved or elliptical shape of a quadratic function of downward convex or upward convex. The polarization direction of the light passing through the polarizing element can be continuously changed according to the position of the light incident on the polarizing element 150. Therefore, it is possible to take an image with reduced reflection over a wide range, and it is possible to improve the performance of object detection and object recognition.

The planar polarizing element 150 of this embodiment can be realized by using a phase plate having a different phase shift amount depending on the position and a polarizing element having a constant polarization direction. At this time, the phase shift amount may be designed at a wavelength intermediate to the vertical cutoff wavelength of the camera, or about 550 nm.

Further, the same effect can be obtained when the camera system is a stereo camera, but as shown in FIG. 20, considering that the front glass 300 in front of the left and right cameras 200L and 200R is inclined in the left-right direction. The normal of the polarizing element 150R for the right camera 200R may be tilted to the front right, and the normal of the polarizing element 150L for the left camera 200L may be tilted to the front left by a small amount. That is, in the form shown in FIG. 20, the normal directions of the polarizing elements 150L and 150R are different from the optical axis of the lens and the lens barrel axis in each of the left and right cameras 200L and 200R.

As described above, the in-vehicle camera system 200 of the embodiment of the present invention includes a camera (camera module 201) including an image pickup element that converts an optical signal into an electric signal and a lens that forms an image of light, and the lens. The polarizing elements 100 and 150 are provided on the front side, and the polarizing elements 100 and 150 change the polarization direction of the light passing through the polarizing elements 100 and 150 according to at least one of the incident angle or the incident position of the light. Therefore, it is possible to take an image with reduced reflection (reflected light) in a wide field of view, improve object detection performance and object recognition performance, and provide a safer in-vehicle camera system 200 and a vehicle having the same.

Further, since the polarizing elements 100 and 150 continuously change the polarization direction of the light passing through the polarizing elements 100 and 150 corresponding to at least one of the incident angle or the incident position of the light, the distortion of the image can be reduced. , Object detection performance and object recognition performance can be improved.

Further, the polarizing element 100 changes the polarization direction of the light passing through with respect to the incident direction by forming a curved surface. In particular, the polarizing element 100 is at least a part of a column or a truncated cone (for example,). Since it is formed of a part of the side surface), the polarizing element 100 can be manufactured by using an inexpensive commercially available polarizing plate.

Also, the attenuation polarization direction of the polarizing element 100 forms a curve. In particular, since the polarization direction of the light passing through the polarizing element 100 forms a straight line parallel to the axis of the column or the truncated cone, the reflected light can be effectively reduced.

Further, since the polarization direction of the light passing through the polarizing element 100 is an angle of 0 to 80 degrees with the optical axis of the lens or the lens barrel axis, the reflected light can be effectively reduced.

Further, since the polarization direction of the light passing through the polarizing element 100 is substantially parallel to the normal line of the reflecting object (windshield 300) in front of the camera, the reflected light can be effectively reduced.

Further, since the opening on the front side of the polarizing element 100 is closed by the light-shielding structure (bracket 400) and the other opening is closed by the camera (vehicle-mounted camera system 200), the polarizing element 100 is directly incident on the inner surface of the polarizing element 100. It is possible to block the light to be emitted, and to improve the object detection performance and the object recognition performance.

Further, since the end portion and the connecting portion of the polarizing element 100 are provided outside the angle of view of the camera, distortion of the image can be reduced, and object detection performance and object recognition performance can be improved.

Further, the polarizing element 150 is represented by a curve in which the polarization direction of the attenuated light has an extreme value of 1 or less, and the curve is convex downward toward the upper side and has a large curvature toward the lower side on the polarizing element. Since it is convex and has a small curvature, or is convex downward and has a large curvature toward the upper side and is convex upward and has a large curvature toward the lower side on the polarizing element 150, light is incident on the polarizing element 150 by using a flat polarizing plate. The polarization direction of the light passing through the polarizing element 150 can be changed according to the position, the structure of the in-vehicle camera system 200 can be simplified, and the assembly can be facilitated.

Further, since the curvature of the curve changes continuously, distortion of the image can be reduced, and object detection performance and object recognition performance can be improved.

Further, since the normal direction of the polarizing element 150 having a planar shape is different from the optical axis of the lens and the lens barrel axis, the reflected light can be effectively reduced even if the front glass 300 is a curved surface.

The present invention is not limited to the above-described embodiment, but includes various modifications and equivalent configurations within the scope of the attached claims. For example, the above-described examples have been described in detail in order to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to those having all the described configurations. Further, a part of the configuration of one embodiment may be replaced with the configuration of another embodiment. Further, the configuration of another embodiment may be added to the configuration of one embodiment. In addition, other configurations may be added / deleted / replaced with respect to a part of the configurations of each embodiment.

Further, each of the above-described configurations, functions, processing units, processing means, etc. may be realized by hardware by designing a part or all of them by, for example, an integrated circuit, and the processor realizes each function. It may be realized by software by interpreting and executing the program to be executed.

Information such as programs, tables, and files that realize each function can be stored in a memory, a hard disk, a storage device such as an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD.

Also, the control lines and information lines indicate those that are considered necessary for explanation, and do not necessarily indicate all the control lines and information lines that are necessary for implementation. In practice, it can be considered that almost all configurations are interconnected.

Claims (16)

1. An on-board camera system that captures the outside world from inside the car
   A camera that includes an image sensor that converts an optical signal into an electrical signal and a lens that forms an image of light.
   A polarizing element provided on the front side of the lens is provided.
   The polarizing element is an in-vehicle camera system characterized in that the polarization direction of light passing through the polarizing element changes according to at least one of an incident angle or an incident position of light.
2. The in-vehicle camera system according to claim 1.
   The polarizing element is an in-vehicle camera system characterized in that the polarization direction of light passing through the polarizing element is continuously changed according to at least one of an incident angle or an incident position of light.
3. The in-vehicle camera system according to claim 1.
   An in-vehicle camera system characterized in that the polarizing element changes the polarization direction of light passing through the incident direction by forming a curved surface.
4. The in-vehicle camera system according to claim 3.
   An in-vehicle camera system, wherein the polarizing element is formed of at least a part of a column or a truncated cone.
5. The in-vehicle camera system according to claim 3.
   An in-vehicle camera system characterized in that the polarization direction of light attenuated by the polarizing element is curved.
6. The in-vehicle camera system according to claim 4.
   An in-vehicle camera system characterized in that the polarization direction of light passing through the polarizing element forms a straight line parallel to the axis of the column or the truncated cone.
7. The in-vehicle camera system according to claim 1.
   An in-vehicle camera system characterized in that the polarization direction of light passing through the polarizing element is an angle of 0 to 80 degrees with the optical axis of the lens or the lens barrel axis.
8. The in-vehicle camera system according to claim 1.
   An in-vehicle camera system characterized in that the polarization direction of light passing through the polarizing element is substantially parallel to the normal line of a reflecting object in front of the camera.
9. The in-vehicle camera system according to claim 4.
   The polarizing element is an in-vehicle camera system characterized in that an opening on the front side is closed by a light-shielding structure.
10. The in-vehicle camera system according to claim 1.
    An in-vehicle camera system characterized in that an end portion and a connecting portion of the polarizing element are provided outside the angle of view of the camera.
11. The in-vehicle camera system according to claim 1.
    The polarizing element is
    The polarization direction of the attenuated light is represented by a curve having an extremum of 1 or less.
    An in-vehicle camera system characterized in that the curve is convex downward and has a large curvature toward the upper side and convex downward and has a small curvature toward the lower side on the polarizing element.
12. The in-vehicle camera system according to claim 1.
    The polarizing element is
    The polarization direction of the attenuated light is represented by a curve having an extremum of 1 or less.
    An in-vehicle camera system characterized in that the curve is convex downward and has a large curvature toward the upper side and convex upward and has a large curvature toward the lower side on the polarizing element.
13. The vehicle-mounted camera system according to claim 12.
    The curve is an in-vehicle camera system characterized in that the curvature changes continuously.
14. The vehicle-mounted camera system according to claim 13.
    The polarizing element has a planar shape and has a planar shape.
    An in-vehicle camera system characterized in that the normal direction of the polarizing element is different from the optical axis of the lens and the lens barrel axis.
15. A vehicle equipped with the in-vehicle camera system according to any one of claims 1 to 14.
16. A polarizing element provided on the front side of the lens of an in-vehicle camera system.
    A polarizing element characterized in that the polarization direction of light passing through the polarizing element changes according to at least one of an incident angle or an incident position of light.

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