Scanning type on-vehicle imaging device

Abstract

To provide an imaging device specialized for optically detecting the approach of objects and complementing conventional imaging devices and sensors for a vehicle by mounting a plurality of imaging elements at different angles on the vehicle, each equipped with a visible light incidence angle restriction section to extract visible light as perpendicular as possible to a light-receiving surface, and designed to absorb impact during vehicle collisions.SOLUTION: It is characterized that a device absorbs impact during vehicle collisions by installing numerous partitions to reduce the directionality of incident visible light other than that perpendicular to a light-receiving surface and mounting a plurality of imaging devices equipped with imaging elements or light sensors behind the visible light incidence angle restriction section at different angles on the vehicle.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an imaging device characterized in that a plurality of image sensors each having a visible light incident angle limiting section that transmits only visible light perpendicular to the light receiving surface are arranged at different angles on a vehicle. [Background technology]

[0002] Currently, in order to enable autonomous driving of vehicles, the surrounding conditions are mainly grasped through digital images, but due to the structure of capturing images by collecting light with a lens on a small image sensor, there is a drawback in that a dirty lens can cause significant defects in the image. In addition, the image sensor of a digital camera has a limited dynamic range, and when there is a large difference in brightness, white blowout and black crush occur, making it impossible to capture an accurate image. Inaccurate image capture is highly dangerous and can lead to an accident. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2009-071676 [Patent Document 2] Patent Publication No. 2009-080846 [Patent Document 3] Patent Publication No. 2009-258632 [Patent Document 4] Patent Publication No. 2022-175162 [Patent Document 5] Patent Publication No. 2023-036549 [Patent Document 6] Patent Publication No. 07-264360 [Patent Document 7] Patent Publication No. 10-107973 [Patent Document 8] CN-A-102177719 [Patent Document 9] CN-U-212278293 [Patent Document 10] KR-A-150140251 [Patent Document 11] KR-A-220104634 [Patent Document 12] Patent Publication No. 11-078737 [Patent Document 13] International Publication No. 2006 / 035510 [Patent Document 14] Patent Publication No. 2012-194055 Summary of the Invention [Problem to be solved by the invention]

[0004] In the past, technologies such as LiDAR and millimeter-wave radar were used in combination to compensate for the shortcomings of in-vehicle digital cameras. However, because LiDAR and millimeter-wave radar rely on reflections from objects, there is a possibility that they may not be able to acquire information depending on the shape and material of the object. This invention complements conventional in-vehicle digital cameras by using a low-resolution, large imaging device to optically capture images and narrow the image range to recognize the center line and detect approaching objects, thereby reducing the possibility of accidents involving self-driving vehicles. [Means for solving the problem]

[0005] In order to achieve the above object, the scanning type in-vehicle imaging device according to claim 1 is characterized in that it comprises a visible light incident angle limiting section provided with a number of partitions to reduce the directivity of incident visible light in directions other than perpendicular to the light receiving surface, and an imaging element or optical sensor is provided behind the visible light incident angle limiting section, which serves to absorb impact in the event of a vehicle collision. [Effects of the Invention]

[0006] The present invention is configured as described above and has the effects described below. When the mechanism according to claim 1 is used, a visible light incident angle limiting unit is provided with multiple partitions for reducing directivity of incident visible light in directions other than perpendicular to the light receiving surface. An imaging device equipped with an image sensor or a photosensor is also disposed in the vehicle behind the visible light incident angle limiting unit. Because the imaging device of the present invention has a narrow imaging range, safety can be further improved by installing multiple or more imaging devices of the present invention at different angles. Because the amplitude of visible light changes in proportion to the light intensity, it is impossible to extract only light in a completely perpendicular direction using partitions, and so it is stated that directivity other than perpendicular to the light receiving surface is reduced.

[0007] To extract visible light as perpendicular to the light-receiving surface as possible, a structure composed of multiple holes penetrating in one direction may be used. By reducing the size of the holes and increasing their depth, the non-vertical directivity of the incident visible light can be further reduced. Furthermore, by blackening the inside of the holes, visible light incident from directions other than the vertical can be absorbed as much as possible. Alternatively, films with multiple slits, each with a width comparable to the amplitude of the visible light to be captured, may be arranged in front and behind the light-receiving surface. The transmission axis of the rear film may be oriented perpendicular to the transmission axis of the front film, thereby transmitting only visible light in the vertical direction. In this case, one of the films may be a polarizing film. For convenience, a portion that extracts visible light as perpendicular to the light-receiving surface as possible is referred to as a visible light incident angle limiting portion. Furthermore, the light-receiving surface refers to the front surface of the visible light incident angle limiting portion. However, when the light-receiving surface is composed of a visible light incident angle limiting portion partition and holes, the light-receiving surface is considered to be a virtual surface that also includes the holes.

[0008] When imaging with visible light that minimizes directivity in directions other than the vertical, the imaging range does not change significantly even with distance, requiring an imaging element of approximately the same size as the desired imaging range. While using the same imaging elements as digital cameras would be extremely expensive, the imaging device of the present invention only needs to detect approaching obstacles and centerlines as a supplement to existing vehicle-mounted cameras and sensors, so a density of approximately one pixel per 5 mm to 1 cm is considered sufficient. With one pixel per 5 mm, an imaging element measuring 1 m wide and 5 cm high would have 2,000 pixels. While recent imaging elements can have pixel counts of over 10 million pixels per square centimeter, the present invention can also use an optical sensor with one pixel per 5 mm to 1 cm square. As mentioned above, the resolution required for imaging in the present invention is extremely low, so the size of the holes through which visible light passes in the visible light incident angle limiting section can function even if they are the size of a single pixel.

[0009] Furthermore, the small number of pixels reduces the amount of information, speeding up image analysis by AI and other technologies. This means that even a low-performance image processing chip can achieve sufficient processing speed, reducing costs and power consumption. Furthermore, a larger image capture device also contributes to safety. For example, with existing cameras, the structure of focusing light through the lens means that even a single insect on the lens can obscure most of the image. However, with this invention, even if around 20% of the image sensor is unable to receive light due to insects or dirt, this does not significantly impede AI image recognition. If there is insufficient light, a mechanism can be provided to automatically turn on the headlights. In this case, it would be even better if the brightness of the lights could be automatically adjusted as needed.

[0010] When placing the imaging device of the present invention on the front of a vehicle, it is better to place it tilted downward from vertical. If it is placed vertically, it may be possible to detect the left and right movement of the subject, but it is difficult to detect the forward and backward movement. However, if it is placed tilted downward from vertical, the imaging device will move upward if the subject moves away, and will move downward if the subject moves closer, so it is possible to detect the approach of the subject and scan the road. Although it is possible to detect the approach of a subject by tilting the imaging device diagonally upward from vertical, it is better to tilt it downward because backlight is more likely to enter.

[0011] The phenomenon of overexposure can be significantly reduced by using a visible light incident angle limiting section to allow the image sensor to receive as much visible light as possible from the perpendicular direction. Also, overexposure occurs in an image sensor that receives strong light from the perpendicular direction, but in this case, another image sensor positioned at a different angle can compensate. The angle of the image sensor may also be adjusted automatically. Furthermore, because the amplitude of visible light changes in proportion to the light intensity, nanoslits may be used in the visible light incident angle limiting section to cut visible light with an amplitude large enough to cause overexposure.

[0012] The image sensor can be made smaller by providing a lattice-shaped, hexagonal, or circularly divided structure between the visible light incident angle limiting unit and the image sensor, providing a lens in each hole of the lattice-shaped, hexagonal, or circularly divided structure, and providing the image sensor in the focal direction of the lens. Also, a light sensor may be used instead of the image sensor.

[0013] The imaging device of the present invention is large in size, which increases its weight, leading to problems with fuel economy and space for installation. However, by making it capable of absorbing impact during a collision, it can be used in place of an existing bumper, thus solving the problems of weight and installation.

[0014] The cameras used in Patent Document 12, Japanese Patent Laid-Open No. 11-078737, and Patent Document 13, International Publication No. 2006 / 035510, are capable of capturing a wide range of images, and the polarizing plate is intended to prevent stray light. If both documents were equipped with a visible light incident angle limiting unit that transmits only visible light perpendicular to the light-receiving surface used in the present invention, the driver would be unable to see outside the windshield in Patent Document 12, which would be dangerous, and the camera would not be able to capture images outside the vehicle. Furthermore, Patent Document 13, International Publication No. 2006 / 035510, combines a camera and radar into a single unit, and the camera itself is a conventional vehicle-mounted camera. Therefore, if Patent Document 13 were to use the visible light incident angle limiting unit of the present invention, it would be useless because it would only be able to capture images within the range of the lens diameter. If the present invention is provided with a visible light incident angle limiting section that transmits only visible light perpendicular to the light receiving surface, it will only be possible to obtain images up to the size of the visible light incident angle limiting section, and so it will have to be used as an auxiliary to conventional vehicle-mounted cameras. However, Patent Document 12 (JP Patent Publication No. 11-078737) and Patent Document 13 (WO 2006 / 035510) do not mention this point and therefore differ from the present invention. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a perspective view showing an embodiment of the invention. [Figure 2] FIG. 1 is a side view showing the first embodiment. [Figure 3] FIG. 1 is a side view showing the first embodiment. [Figure 4] FIG. 10 is a side view showing the second embodiment. [Figure 5] FIG. 10 is a top view showing Example 3. [Figure 6] FIG. 10 is a perspective view showing a fourth embodiment. [Figure 7] FIG. 10 is a cross-sectional view showing Example 5. [Figure 8] FIG. 10 is a perspective view showing a sixth embodiment. [Figure 9] FIG. 10 is a perspective view showing a sixth embodiment. [Figure 10] FIG. 10 is a side view showing Example 7. [Figure 11] FIG. 10 is a cross-sectional view showing Example 8. [Figure 12] FIG. 13 is a perspective view showing Example 9. DETAILED DESCRIPTION OF THE INVENTION

[0016] An embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a perspective view of a vehicle (5) equipped with multiple scanning-type vehicle-mounted imaging devices mounted on the front of the vehicle. The visible light incident angle limiting portion (1a) of the imaging device is tilted slightly downward from the vertical. The visible light incident angle limiting portion (1b) of the imaging device is tilted downward from the visible light incident angle limiting portion (1a) of the imaging device. The visible light incident angle limiting portion (1c) of the imaging device is tilted downward from the visible light incident angle limiting portion (1b) of the imaging device. In the event of a vehicle collision, these scanning-type vehicle-mounted imaging devices break, thereby absorbing the impact.

[0017] The visible light incident angle limiting section (2c) of the imaging device is tilted slightly to the right from the front. The visible light incident angle limiting section (2b) of the imaging device is tilted more to the right than the visible light incident angle limiting section (2c) of the imaging device. The visible light incident angle limiting section (2a) of the imaging device is tilted more to the right than the visible light incident angle limiting section (2b) of the imaging device.

[0018] The visible light incident angle limiting section (2d) of the imaging device is tilted slightly leftward from the front. The visible light incident angle limiting section (2e) of the imaging device is tilted further leftward than the visible light incident angle limiting section (2d) of the imaging device. The visible light incident angle limiting section (2f) of the imaging device is tilted further left than the visible light incident angle limiting section (2e) of the imaging device. [Example]

[0019] Example 1 will be described with reference to FIGS. 2 and 3. FIG. 2 is a side view showing the imaging range of a scanning-type vehicle-mounted imaging device attached to the front. The visible light incident angle limiting section (1a-1c) of the imaging device is installed in front of the vehicle (5a). The visible light incident angle limiting section (1a) of the imaging device is tilted slightly downward from the vertical. The visible light incident angle limiting section (1b) of the imaging device is tilted downward from the visible light incident angle limiting section (1a) of the imaging device. The visible light incident angle limiting section (1c) of the imaging device is tilted downward from the visible light incident angle limiting section (1b) of the imaging device. The imaging range (3a) extends perpendicularly from the upper and lower ranges of the visible light incident angle limiting section (1a) of the imaging device to capture a portion of the rear of the vehicle (5b). The imaging range (3b) extends perpendicularly from the upper and lower ranges of the visible light incident angle limiting section (1b) of the imaging device to capture the road surface (6). The imaging range (3c) extends perpendicularly from the range above and below the visible light incident angle limiting section (1c) of the imaging device to capture the road surface (6). A blind spot (4a) that cannot be imaged exists between the imaging range (3a) and the imaging range (3b). A blind spot (4b) that cannot be imaged exists between the imaging range (3b) and the imaging range (3c). The blind spot may be reduced by providing more visible light incident angle limiting sections of the imaging device.

[0020] As shown in FIG. 3, if the distance between the vehicles (5a) and (5b) is reduced, a part of the rear of the vehicle (5b) is captured in the imaging range (3b), so that approaching obstacles can be detected even if there are blind spots (4a, 4b).

[0021] A second embodiment will be described with reference to FIG. 4. Incident light (7) becomes reflected light (8) on the road surface (6), and the angle of the reflected light (8) matches the angle of the imaging range (3b) of the visible light incident angle limiting unit (1b) of the imaging device. If the incident light (7) is strong light such as sunlight, there is a high possibility that the image captured by the visible light incident angle limiting unit (1b) of the scanning-type vehicle-mounted imaging device will be overexposed. However, in this case, the imaging ranges (3a, 3c) of the visible light incident angle limiting units (1a, 1c) of the other imaging devices differ from the reflection angle of the reflected light (8), so overexposure does not occur and the device can function as intended. The angle of the visible light incident angle limiting unit of the imaging device may be automatically changed.

[0022] A third embodiment will be described with reference to Fig. 5. Fig. 5 is a top view showing the imaging range of a scanning-type in-vehicle imaging device attached to the front. The visible light incident angle limiting section (1a) of the imaging device is installed in front of the vehicle (5a), and the imaging range (3a) extends in perpendicular directions from the left and right ranges of the visible light incident angle limiting section (1a) of the imaging device.

[0023] The visible light incident angle limiting section (2a-2c) of the imaging device is installed on the right front of the vehicle (5a). The visible light incident angle limiting section (2a) of the imaging device faces diagonally to the right from the front. The visible light incident angle limiting section (2b) of the imaging device faces slightly more forward than the visible light incident angle limiting section (2a) of the imaging device. The visible light incident angle limiting section (2c) of the imaging device faces slightly more forward than the visible light incident angle limiting section (2b) of the imaging device. The imaging range (9a) extends perpendicularly from the left and right range of the visible light incident angle limiting section (2a) of the imaging device. The imaging range (9b) extends perpendicularly from the left and right range of the visible light incident angle limiting section (2b) of the imaging device. The imaging range (9c) extends perpendicularly from the left and right range of the visible light incident angle limiting section (2c) of the imaging device. The imaging ranges (9a-9c) enable optical detection of obstacles approaching from the right front as viewed from the vehicle (5a).

[0024] The visible light incident angle limiting section (2d-2f) of the imaging device is installed on the left front of the vehicle (5a). The visible light incident angle limiting section (2d) of the imaging device faces diagonally left from the front. The visible light incident angle limiting section (2e) of the imaging device faces slightly to the left of the visible light incident angle limiting section (2d) of the imaging device. The visible light incident angle limiting section (2f) of the imaging device faces slightly to the left of the visible light incident angle limiting section (2e) of the imaging device. The imaging range (9d) extends perpendicularly from the left and right range of the visible light incident angle limiting section (2d) of the imaging device. The imaging range (9e) extends perpendicularly from the left and right range of the visible light incident angle limiting section (2e) of the imaging device. The imaging range (9f) extends perpendicularly from the left and right range of the visible light incident angle limiting section (2f) of the imaging device. The imaging ranges (9d-9f) enable optical detection of obstacles approaching from the left front as seen from the vehicle (5a). A similar system may also be installed at the rear of the vehicle.

[0025] Example 4 will be described with reference to Fig. 6. Fig. 6 is a perspective view showing a visible light incident angle limiting section (10) and an imaging element (11). The visible light incident angle limiting section (10), which has a structure divided into lattice shapes, is provided in front of the visible light incident angle limiting section of the single-plate imaging element (11).

[0026] Since the visible light incident angle limiting unit only needs to reduce light in directions other than the orthogonal direction as much as possible, it can also function by placing a structure partitioned in a direction perpendicular to the light receiving surface of the image sensor (11) in front of the image sensor and painting the inside of the holes with a paint that has a high light absorption rate. In this case, the angle of incidence of light on the image sensor can be further limited by reducing the size of the lattice and increasing the depth of the structure. The shape of the holes in the visible light incident angle limiting unit (10) can be either hexagonal or circular. The structure of the visible light incident angle limiting unit (10) can be given the role of shock absorption, like a bumper.

[0027] A fifth embodiment will be described with reference to FIG. 7. FIG. 7 is a cross-sectional view of an imaging device using a lens (12) behind the visible light incident angle limiting section (10). Partitions (13) are arranged behind the visible light incident angle limiting section (10), and lenses (12) and optical sensors (15) are arranged within each partition of the partitions (13). Light transmitted through the visible light incident angle limiting section (10) is collected by each lens (12) into each optical sensor (15). The optical sensors (15) need only be able to distinguish monochrome, but they must be able to distinguish a certain degree of gradation. Since an optical sensor basically only functions as one pixel of an imaging element, when optical sensors are used, the substrate (14) must be equipped with as many optical sensors (15) as the required number of pixels. The partitions (13) are given the role of shock absorption, like a bumper.

[0028] Example 6 will be described with reference to Figures 8 and 9. Figure 8 shows the partitions (16) of film a for limiting the angle of incidence of visible light, in which the slit width is approximately the same as the amplitude of the visible light to be acquired, and the visible light (17a, 17b, 17c) that passes through the film. Because the transmission axis is horizontal, visible light other than that incident horizontally on the light-receiving surface of the film for limiting the angle of incidence of visible light is attenuated. However, since the film is horizontal, it is ineffective against visible light incident from left and right angles, and therefore visible light (17a, 17c) other than visible light (17b) incident from the perpendicular direction on the light-receiving surface of the film for limiting the angle of incidence of visible light also passes through without attenuation. For convenience, a film with many slits that are approximately the same as the amplitude of the visible light to be acquired will be referred to as a film for limiting the angle of incidence of visible light.

[0029] Figure 9 shows a diagram of a visible light incident angle limiting film b with a partition (18) whose transmission axis is perpendicular to the partition (16) of the visible light incident angle limiting film a, which has a horizontal transmission axis. This allows for attenuation of visible light (17b) other than that coming perpendicular to the surface of the visible light incident angle limiting film. Alternatively, either of the front or rear visible light incident angle limiting films may be a polarizing film. Because the amplitude of light varies depending on its intensity, visible light with an amplitude smaller than the slit width will be incident at an angle other than perpendicular. Therefore, even if the slit is made small enough to the nanometer scale, it is not possible to extract only light that is completely perpendicular. However, it is possible to limit the intensity of the light captured by adjusting the slit width, thereby suppressing the phenomenon of overexposure.

[0030] A seventh embodiment will be described with reference to Fig. 10. Unlike Figs. 1 to 4, Fig. 10 shows that the visible light incident angle limiting units (1a to 1c) of the imaging device are arranged so as to be recessed into the body of the vehicle (5a). Therefore, while Fig. 1 shows that the visible light incident angle limiting unit (1a) of the imaging device captures the most distant image, Fig. 10 shows that the visible light incident angle limiting unit (1c) of the imaging device can capture the most distant image. Advantages of storing the imaging device inside the vehicle include the ability to reduce damage due to contact by attaching a cover (19) and the ease of attaching wipers as a measure against heavy rain.

[0031] Example 8 will be described with reference to Fig. 11. Fig. 11 is a cross-sectional view showing a configuration in which light collected by each lens (12) is collected into a single imaging element (23) by bundling all of the optical cables (21) together instead of using an optical sensor (15). Partitions (13) are arranged behind the visible light incident angle limiting unit (10), and lenses (12) and optical cable light receiving units (20) are arranged within each partition of the partition (13). Light transmitted through the visible light incident angle limiting unit (10) is collected by each lens (12) into the light receiving units (20) of the optical cables, and further collected from the light receiving units (20) of the optical cables through the optical cables (21) to the imaging elements (23) connected by the connectors (22).

[0032] Example 9 will be described with reference to Figure 12. Figure 12 is a perspective view of Figure 7, and the visible light incident angle limiting section (24) uses a structure consisting of many holes that penetrate vertically in order to reduce directivity in directions other than perpendicular to the light receiving surface. A transparent cover is attached in front of the visible light incident angle limiting section (24) to prevent dust, insects, etc. from entering the holes. The shape of the holes in the partition with many holes that penetrate in one direction may be circular or polygonal. Furthermore, when slits are used, two or more panels must be arranged so that the slits intersect, as shown in Figure 9. [Explanation of symbols]

[0033] 1a Visible light incident angle limiting section of imaging device 1b Visible light incident angle limiting section of imaging device 1c Visible light incident angle limiting section of imaging device 2a Visible light incident angle limiting section of imaging device 2b Visible light incident angle limiting section of imaging device 2c Visible light incident angle limiting section of imaging device 2d Visible light incident angle limiting section of imaging device 2e Visible light incident angle limiting section of imaging device 2f Visible light incident angle limiting section of imaging device 3a Imaging range 3b Image capture area 3c Image Range 4a blind spot 4b blind spot 5 vehicles 5a Vehicle 5b Vehicle 6 Road surface 7 Incident light 8 Reflected light 9a Imaging range 9b Image capture area 9c Image Range 9d imaging range 9e Imaging range 9f imaging range 10 Visible light incident angle limiting section 11 Image sensor 12 Lenses 13 Partition 14 Foundation 15. Optical Sensor 16 Partition of visible light incident angle limiting film a 17a visible light 17b visible light 17c visible light 18 Partition of visible light incident angle limiting film b 19 Cover 20 Optical cable light receiving part 21 Optical Cable 22 Connectors 23 Image sensor 24 Visible light incident angle limiting section

Claims

[Claim 1] An in-vehicle imaging device comprising: a visible light incident angle limiting section provided with a number of partitions for reducing directivity of incident visible light in directions other than perpendicular to the light receiving surface; and an imaging element or optical sensor provided behind the visible light incident angle limiting section, which serves to absorb impact in the event of a vehicle collision.

Images