JP6179975B2 - Back monitor camera, vehicle, back monitor system, and back monitor method - Google Patents

Description

  The present invention relates to a back monitor camera installed on the rear surface of a vehicle, a vehicle in which the back monitor camera is installed, a back monitor system using the back monitor camera, and a back monitor method using the back monitor camera.

  For example, when an automobile, which is a vehicle, is moved backward and placed in a parking lot, the driver usually operates the automobile while confirming the rear. However, since the lower part of the rear window shield cannot be viewed with this, for example, even if an obstacle such as a soccer ball rolls behind the automobile, the vehicle may come into contact with the ball without noticing it. In order to prevent this, a back monitor camera may be installed on the rear surface of the automobile.

  As shown in FIG. 7, such a back monitor camera 10 is installed at the substantially center of the rear surface of the automobile CR equipped with a rear bumper RB below. Such a back monitor camera 10 is different from a normal camera because, for example, in accordance with the US standard, the entire parking lot PS having a lateral width of 3 m and a front and rear of 6 m is imaged from a short distance. Therefore, the imaging optical system is close to a fisheye lens. For example, as shown in FIG. 7, the captured image of the back monitor camera 10 with the angle of view of the imaging optical system of 130 ° to 140 ° is 3 m behind the automobile CR as described above, as shown in FIG. Thus, the entire parking lot PS at the front and rear of 6 m is curved and imaged.

  However, in the back monitor camera 10 having an angle of view of 130 ° to 140 ° as described above, the left and right ends of the rear bumper RB are inevitably captured because of the relative position. For this reason, when the automobile CR is moved backward and moved to the parking lot PS while confirming the rear in the captured image of the back monitor camera 10, the left end or the right end of the rear bumper RB may be brought into contact with a wall surface or the like. .

  In order to prevent this, for example, as shown in FIG. 9, there is a back monitor camera using a fisheye lens of an equidistant projection method having an angle of view of 180 ° or more. In such a back monitor camera, as shown in FIG. 10, the entire rear bumper RB is imaged together with the entire parking lot PS having a lateral width of 3 m and a front and rear of 6 m of the automobile CR. However, in this case, although the left end and the right end of the rear bumper RB are imaged, the captured image of the rear parking lot PS is very curved.

  In order to solve this problem, for example, there is a product such as a camera device described in Patent Document 1 that enlarges the captured image by image processing using an electronic circuit or software so that the sense of distance can be easily grasped. is there. In this camera device, as a lens configuration, the relationship between the image height of each image portion on the image formed on the image sensor and the angle of view of the light ray incident on each image portion (incident angle with respect to the optical axis) FIG. 11A shows an image obtained by an imaging apparatus configured such that the amount of change in the image height with respect to the change in the angle of view is larger in the peripheral portion than in the central portion of the image. Thus, the central region 21 of the image 20 is cut out and the central region 21 is enlarged as shown in FIG.

JP 2011-193485 A

  As described above, in a general back monitor camera 10 having an angle of view of 130 ° to 140 °, the rear distance feeling is easily grasped, but the left and right ends of the rear bumper RB are not imaged. For this reason, when the automobile CR is retracted and parked in the parking lot PS while confirming the rear in the captured image of the back monitor camera 10, the left and right ends of the rear bumper RB may come into contact with the wall surface and be damaged. .

  On the other hand, in the back monitor camera using a fisheye lens with an angle of view of 180 ° or more, the left and right ends of the rear bumper are confirmed, but the captured image of the rear parking lot PS is very curved, so the sense of distance is grasped. Hard to do.

  Further, in the camera device described in Patent Document 1, there is a problem that the lens itself has a large distortion in the central region of the lens due to the relationship between the image height and the angle of view, and it is difficult to obtain a clear image. Since the area is enlarged by image processing, there is a problem that the structure of the apparatus is complicated and expensive. In addition, since it mainly captures the rear of the vehicle, it is difficult to grasp the position of the vehicle itself. Therefore, as with the general back monitor camera described above, the left and right ends of the rear bumper are brought into contact with the wall surface. May cause damage.

  The present invention has been made in view of the above-described problems, and provides a back monitor camera, a vehicle, and a back monitor method for solving the above problems.

  The back monitor camera of the present invention is a back monitor camera installed on the rear surface of a vehicle equipped with a slender rear bumper in the left-right direction, and an image pickup device array in which a plurality of image pickup devices are arranged in a matrix The angle of view of the central region is smaller than that of the fisheye lens, the size of the central region is larger than the peripheral region, and the angle of view of the peripheral region extends to the left and right ends of the rear bumper. And an imaging optical system having an angle of view within a range of 140 degrees to 190 degrees.

  The vehicle according to the present invention includes a vehicle body equipped with an elongated rear bumper in the left-right direction, and the back monitor camera equipped on the rear surface of the vehicle body.

  The back monitor system of the present invention is a back monitor system for a vehicle equipped with a rear bumper elongated in the left-right direction and the back monitor camera on the rear surface of the vehicle body, wherein the vehicle length of the vehicle is L1, and the vehicle width is L2. The parking space display in the range of L1 + 600 mm to 1000 mm in the front-rear direction and L2 + 400 mm to 1000 mm in the left-right direction is attached to the parking surface of the parking lot, and the imaging optical system enters the parking space display of the vehicle. During the garage entry operation, both ends of the rear bumper and the left and right ends and the rear end of the parking space are imaged.

  The back monitor method of the present invention is a back monitor method by a back monitor camera installed on the rear surface of a vehicle equipped with a slender rear bumper in the left-right direction. The angle of view is smaller than that of the fisheye lens, and an optical system in which the size of the central region is larger than the peripheral region is used, and the left and right ends of the rear bumper are connected to the image sensor array in the peripheral region of the imaging optical system. It is a method to image.

  In the back monitor method using the back monitor camera of the present invention, since the curvature of the central area of the rear captured image to be captured and displayed is small, it is easy to grasp the sense of distance when the vehicle is moved backward to the parking lot. Since the region has a large curvature and the left and right ends of the rear bumper can be imaged, it is possible to prevent the left and right ends of the rear bumper from contacting the wall surface when the vehicle is moved backward to the parking lot. In addition, since the configuration is simple, it can be provided at low cost.

4A is a schematic plan view of a back monitor camera according to an embodiment of the present invention, and FIG. 4B is a schematic diagram illustrating a relative relationship between an imaging range and an angle of view. (A), (b) is a figure which shows the relationship between the incident angle and image height of a common fisheye lens and an example of the imaging optical system which concerns on this invention. It is a typical vertical side view which shows the optical structure of the back monitor camera in embodiment of this invention. It is a perspective view which shows the external appearance of the motor vehicle which is a vehicle in which the back monitor camera in embodiment of this invention was installed. It is a typical top view which shows the positional relationship of the motor vehicle and parking lot in which the back monitor camera in embodiment of this invention was installed. It is a schematic diagram which shows the picked-up image of the back monitor camera in embodiment of this invention. It is a typical top view which shows the positional relationship of the motor vehicle in which the back monitor camera in the prior art example was installed, and a parking lot. It is a schematic diagram which shows the captured image of the back monitor camera in one prior art example. It is a schematic diagram which shows the relative relationship between the imaging range of a fisheye lens, and an angle of view. It is a schematic diagram which shows the captured image of the back monitor camera which uses a fisheye lens. (A), (b) is a schematic diagram which shows the picked-up image of the camera apparatus in one prior art example.

  An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1A, the back monitor camera 100 of the present embodiment is installed on the rear surface of an automobile CR, which is a vehicle equipped with an elongated rear bumper RB in the left-right direction. As shown in FIG. 1B, the image pickup device array 110 in which the image pickup devices 111 such as CCDs are arranged in a matrix, and the rear bumper RB in the peripheral region having a larger central area with a smaller angle of view than the fisheye lens and a larger angle of view. And an imaging optical system 120 that forms an image on the imaging element array 110 at both left and right ends.

  As shown in FIG. 3, the imaging optical system 120 of the back monitor camera 100 of the present embodiment is actually a first lens 121, a second lens 122, a third lens 123, a fourth lens 124, and a fifth lens. A glass 125 and a sixth glass 126 are included. The first lens 121 collects light incident from the outside onto the image sensor array 110. The second lens 122 collects light incident from the outside onto the image sensor array 110 and varies the distortion between the central region and the peripheral region of the imaging range. The third lens 123 corrects the aberration. The fourth lens 124 corrects aberrations and reflects unnecessary light rays on the surface. The fifth glass 125 blocks infrared rays by reflection and absorption. The sixth glass 126 protects the imaging element array 110.

  Such a back monitor camera 100 is installed on the rear surface of the automobile CR equipped with an elongated rear bumper RB in the left-right direction, as shown in FIGS. In this case, the back monitor camera 100 is installed at a height of 80 to 95 mm from the ground, a position within ± 250 mm from the center of the vehicle body, and an angle of 48 ° with the ground. Thus, the back monitor camera 100 installed on the rear surface of the automobile CR generates an angle of view of 180 ° to 190 ° as shown in FIG.

  In the imaging optical system 120, the angle of view of the central region is smaller than that of the fisheye lens, and the size of the central region is larger than the peripheral region. That is, as shown in FIG. 1B, the central region having a small angle of view such as 20 ° or 60 ° is large, and the peripheral region having a large angle of 100 ° or 180 ° is formed only in the vicinity of the outer edge. The angle of view of the peripheral region is desirably in the range of 140 ° to 190 ° so that the left and right ends of the rear bumper RB are imaged on the image sensor array 110 as described later.

FIGS. 2A and 2B are diagrams showing the relationship between the incident angle (field angle) of the imaging optical system and the image height, and an example of a general fisheye lens and an imaging optical system according to the present invention. FIG.
As shown in these drawings, in the imaging optical system 120 according to the present invention, the amount of change in the image height with respect to the change in the incident angle is smaller in the peripheral region than in the central region of the image. Therefore, the central region with a smaller incident angle is reflected more widely and has less distortion.
In this example, the angle of view of the imaging optical system 120 can be secured up to 180 ° on both the left and right sides.
In addition, the imaging optical system 120 of this example has a larger central area with a small angle of view and a smaller peripheral area with a large angle of view than a fisheye lens of an orthogonal projection method.

  On the other hand, as shown in FIGS. 5 and 6, the back monitor camera 100 of the present embodiment, for example, corresponds to the US standard and the like, and covers the entire parking lot PS having a lateral width of 3 m behind the automobile CR and a front and rear of 6 m. The imaging optical system 120 is adjusted so that imaging can be performed from a short distance. For this reason, in the back monitor camera 100 of the present embodiment, the rear parking lot PS having a lateral width of 3 m is incident on the imaging optical system 120 at an inner angle of 80 °, for example. In this case, an existing general fisheye lens forms an image on the image sensor array with an image height of “100” as “40 (%)”, but the imaging optical system 120 of the back monitor camera 100 of the present embodiment. Then, the image is formed on the image sensor array 110 as “75 (%)”.

  In the back monitor camera 100 of the present embodiment, as described above, the imaging optical system 120 is adjusted so that the entire parking lot PS having a lateral width of 3 m behind the automobile CR and a front and rear 6 m can be imaged from a short distance. However, as described above, it is set so that the left and right ends of the rear bumper RB are imaged on the image sensor array 110 in the peripheral region having a large angle of view. For this reason, in the back monitor camera 100 of the present embodiment, as shown in FIG. 6, the captured image of the rear parking lot PS has a necessary minimum curvature in the central region of the small angle of view.

  Therefore, it is easy to grasp the sense of distance from the captured image of the back monitor camera 100, and the vehicle CR can be moved backward to the parking lot PS while confirming the rear side with the captured image. Further, in the back monitor camera 100 of the present embodiment, the left and right ends of the rear bumper RB are also imaged in the peripheral region with a large angle of view. For this reason, it is possible to prevent the left end and the right end of the rear bumper RB from coming into contact with the wall surface or the like when the automobile CR is moved backward to the parking lot PS while confirming the rear from the captured image of the back monitor camera 100.

  Further, as described above, the back monitor camera 100 can capture the rear parking lot PS in the central area with a small angle of view with a minimum curvature, and the left and right ends of the rear bumper RB in the peripheral area with a large angle of view. However, this is realized only by the imaging optical system 120 in which the central area of the small angle of view is larger and the peripheral area of the large angle of view is smaller than the fisheye lens of the orthographic projection method. With this configuration, when the vehicle is moved backward to the parking lot behind, the central region of the imaging optical system 120 is widely reflected and there is little distortion. Therefore, it is easy to grasp the sense of distance, and parking can be performed easily. Further, it is not necessary to correct the captured image by an electronic circuit or software, and the structure is simple and can be provided at low cost.

  In the back monitor camera 100 of the present embodiment, the imaging optical system 120 forms an image of the entire parking lot PS having a shape and size corresponding to the automobile CR on the image sensor array 110. More specifically, the entire parking lot PS of at least 6 m in the front-rear direction and 3 m in the left-right direction is imaged on the image sensor array 110. For this reason, the whole general parking lot PS can be imaged and parking can be facilitated, and US standards can be cleared.

As a modification of the above-described embodiment, the present invention can be configured so that the resolution of the output image of the image sensor array 110 is higher in the peripheral region than in the central region.
The configuration of this resolution can be realized by arranging the image pickup devices 111 of the image pickup device array 110 with higher density in the peripheral region than in the central region, or by processing the output image of the image pickup device array 110.
In such a configuration, the image in the peripheral area is compressed with high density, but the resolution of the image is high so that the image can be clearly seen. The positions of both ends of the RB can be clearly confirmed.

As another modification, the first image processing unit 300 that adjusts the luminance of the peripheral region with respect to the central region with respect to the output image of the image sensor array 110 (see FIG. 1A). Can be provided.
In such a configuration, when the vicinity of the parking space is dark due to the weather or the surrounding environment of the parking space, the positions of both ends of the rear bumper RB with respect to the parking space are increased as described above by increasing the brightness of the surrounding region. Can be clearly confirmed.

As another modification, a second image processing unit 301 that adds auxiliary lines for displaying the positions of the left and right ends of the rear bumper RB to the output image of the image sensor array 110 (see FIG. 1A). Can be provided.
When configured in this way, the positions of the left and right ends of the rear bumper RB can be clearly confirmed from the captured image, and the vehicle CR is retracted and parked while confirming the rear from the captured image of the back monitor camera 100. When moving to the car park PS, it is possible to satisfactorily prevent the left and right ends of the rear bumper RB from coming into contact with the wall surface.

As another modification, third image processing is performed in which an angle-of-view line 400 for displaying an angle of view near the outer edge of the central region is added to the output image of the image sensor array 110 as shown in FIG. A portion 302 (see FIG. 1A) can be provided.
When configured in this manner, the boundary between the small field angle region and the large field angle region can be confirmed, and the moving state of the vehicle can be clearly grasped by confirming the portion where the image density changes rapidly. be able to.

Further, according to the present invention, a vehicle back monitor system can be configured using the above back monitor camera.
For example, when the vehicle length of the vehicle is L1 and the vehicle width is L2, a parking space display in the range of L1 + 600 mm to 1000 mm in the front-rear direction and L2 + 400 mm to 1000 mm in the left-right direction is attached to the parking surface of the parking lot.
The imaging optical system 120 forms an image of both ends of the rear bumper and both the left and right ends and the rear end of the parking space when the vehicle is put into the parking space display.
The size of the parking space is set in the above range in consideration of the passage of people after parking in the front and rear of the space, and the opening and closing of doors, the passage of people, etc. in the left-right direction.
According to this structure, parking can be easily performed without an accident like said embodiment and each modification.

  The various components of the present invention do not necessarily have to be independent of each other. A plurality of components are formed as a single member, and a single component is formed of a plurality of members. A certain constituent element is a part of another constituent element, a part of a certain constituent element and a part of another constituent element are allowed to overlap. In the above-described embodiment, the structure of each part has been specifically described. However, the present invention is not limited to this embodiment, and various modifications are allowed without departing from the scope of the invention. The structure and the like can be changed in various ways as long as the present invention is satisfied.

DESCRIPTION OF SYMBOLS 100 Back monitor camera 110 Image pick-up element array 111 Image pick-up element 120 Imaging optical system 300 1st image processing part 301 2nd image processing part 302 3rd image processing part 400 Angle of view CR Automobile which is a vehicle PS Parking lot RB rear bumper

Claims (8)

A back monitor camera installed on the rear side of a vehicle equipped with an elongated rear bumper in the left-right direction,
An image pickup device array in which a plurality of image pickup devices are arranged in a matrix;
The angle of view of the central region is smaller than that of the fisheye lens, the size of the central region is larger than the peripheral region, and the angle of view of the peripheral region is set at the left and right ends of the rear bumper to the image sensor array. An imaging optical system having an angle of view within a range of 140 to 190 degrees to form an image;
I have a,
A third image processing unit that adds an angle-of-view line that displays an angle of view near the outer edge of the central region to the output image of the image sensor array;
Back monitor camera. In the imaging optical system, the central region has a smaller angle of view than a fisheye lens of an orthogonal projection method,
The back monitor camera according to claim 1. The output image of the image sensor array is configured such that the resolution is higher in the peripheral area than in the central area.
The back monitor camera according to claim 1 or 2. A first image processing unit that adjusts the brightness of the peripheral region with respect to the central region with respect to the output image of the image sensor array;
The back monitor camera according to any one of claims 1 to 3. A second image processing unit for adding auxiliary lines for displaying the positions of the left and right ends of the rear bumper to the output image of the image sensor array;
The back monitor camera as described in any one of Claim 1 to 4. A vehicle body equipped with an elongated rear bumper in the left-right direction;
The back monitor camera according to any one of claims 1 to 5 , which is mounted on a rear surface of the vehicle body,
Vehicle having. A vehicle back monitor system comprising a rear bumper that is elongated in the left-right direction and the back monitor camera according to any one of claims 1 to 5 on the rear surface of the vehicle body,
When the vehicle length of the vehicle is L1 and the vehicle width is L2,
Parking space indications in the range of L1 + 600mm to 1000mm in the front-rear direction and L2 + 400mm to 1000mm in the left-right direction are attached to the parking surface of the parking lot,
The imaging optical system is
At the time of garage operation in the parking space display of the vehicle, both ends of the rear bumper and the left and right ends and the rear end of the parking space are imaged.
Vehicle back monitor system. A back monitoring method by a back monitor camera installed on the rear surface of a vehicle equipped with an elongated rear bumper in the left-right direction,
As the imaging optical system, an optical system in which the angle of view of the central region is smaller than that of the fisheye lens, and the size of the central region is larger than the peripheral region, and the optical region in the peripheral region of the imaging optical system is The left and right ends of the rear bumper are imaged on the image sensor array ,
Adding an angle-of-view line that displays an angle of view near the outer edge of the central region to the output image of the image sensor array;
Back monitor method.