JP2012049892A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a resolution of an area within a picked-up image where the vicinity of an imaging apparatus is imaged with a simple structure.SOLUTION: An imaging apparatus comprises: lenses 13(i is an integer from 1 to 6) which concentrate light; and an imaging device 14 which converts the light concentrated by the lenses 13into an electrical signal. The imaging device 14 has a distance from the lenses and an angle against the lenses determined so that a diameter of a circle of confusion where the light arriving the lens 13from a photographic subject in a prescribed distance range from the lens 13focuses on the imaging device 14 may become smaller than a prescribed length, and that a diameter of a circle of confusion where the light arriving at the lens 13from a photographic subject at a distance outside of the prescribed distance range from the lens 13focuses on the imaging device 14 may become equal to or larger than the prescribed length.

Description

  The present invention relates to an imaging apparatus.

Conventionally, an in-vehicle camera is used to image the front of a vehicle and detect a white line on a road or an obstacle on traveling. FIG. 16 is a diagram illustrating an example of a mounting structure of a lens and an imaging element of a conventional imaging device. The conventional imaging device 101 includes an optical unit 110 and a control unit 20.
The optical unit 110 includes a lens holder 111, a lens barrel 112, six lenses 113 _i (i is an integer from 1 to 6), an image sensor 114, and an A / D converter 115.
The image sensor 114 is installed such that the distance from the rear principal point to the image sensor surface is the focal length f.

  Further, in Patent Document 1, in order to improve the visibility of an object to be monitored from a restricted installation position, in an in-vehicle camera device that is mounted on a vehicle and images the inside or outside of the vehicle, the imaging lens and the imaging lens are used. It is shown that an image pickup device that converts the obtained image into an electric signal is provided, and the reading region of the image pickup device and the image pickup lens are arranged in a positional relationship where an effect is produced.

JP 2001-285701 A

However, in the conventional in-vehicle camera, the number of pixels of the image sensor of the in-vehicle camera is selected so as to obtain a resolution for detecting a distant object, so that the resolution is excessive in the vicinity of the in-vehicle camera. As a result, there is a drawback in that the calculation processing in the subsequent calculation unit becomes heavy.
Conventionally, there has been a problem that the calculation unit in the subsequent stage needs to apply a filter that lowers the resolution of the portion where the vicinity of the own vehicle is imaged with respect to the image obtained by the in-vehicle camera.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide an imaging apparatus that can reduce the resolution of an area in the vicinity of the imaging apparatus in the captured image.

[1] In order to solve the above-described problem, an imaging apparatus according to one embodiment of the present invention includes a lens that collects light, and an imaging element that converts light collected by the lens into an electrical signal. The imaging element has a diameter of a first circle of confusion on the imaging element from which light arriving at the lens from a subject within a predetermined distance range from the lens is smaller than a predetermined length, and from the lens The distance from the lens and the distance to the lens so that the diameter of the second circle of confusion that the light arriving at the lens from the subject outside the predetermined distance range joins on the image sensor is not less than the predetermined length. The angle is determined.
According to the above imaging device, it is possible to focus on a subject within a predetermined distance range, and to stop focusing on a subject outside the predetermined distance range. Among them, the resolution of the area where the vicinity of the imaging device included outside the predetermined distance range is imaged can be lowered.

[2] In the imaging device according to [1], the distance from the lens of the first circle of confusion ranges from a short distance from the focal distance to the focal depth to a long distance from the focal distance to the focal depth. The distance from the lens of the second circle of confusion is out of a range from a short distance from the focal distance to the focal depth to a long distance from the focal distance to the long focal depth. The angle is not parallel to the lens.
According to this, the position and lens in which the imaging element can focus on a subject within a predetermined distance range and can not focus on a subject outside the predetermined distance range. Therefore, it is possible to reduce the resolution of the area in which the vicinity of the imaging device included outside the predetermined distance range in the captured image is captured.

[3] In the imaging apparatus according to [1], the imaging element may have a distance from the lens from the focal length of the lens to a distance shorter than the focal length of the lens by a focal depth. It is characterized by being parallel.
According to this, the imaging element can be focused on a subject in a predetermined distance range, and can be out of focus on a subject outside the predetermined distance range, Since it is installed horizontally with the lens, the resolution of the area where the vicinity of the imaging device included outside the predetermined distance range in the captured image is captured can be lowered.

[4] In the imaging apparatus according to [1], a drive unit that moves one end of the imaging device to change an angle of the imaging device, an angle calculation unit that calculates an angle of the imaging device with respect to the lens, Based on the calculated angle, a movement amount calculation unit that calculates a movement amount of one end of the imaging element, and a drive control unit that controls the driving unit so that one end of the imaging element moves the calculated movement amount And.
According to this, since the angle of the imaging element can be adjusted, even if the imaging condition changes, the resolution of the area where the vicinity of the imaging device included outside the predetermined distance range in the captured image is reduced is reduced. Can do.

[5] In the imaging apparatus according to [4], the angle calculation unit calculates an angle of the imaging element with respect to the lens based on depression angle information indicating an depression angle of the own apparatus with respect to the ground. It is characterized by.
According to this, since the angle of the image sensor with respect to the lens can be calculated based on the depression angle information, even if the depression angle of the imaging apparatus with respect to the ground is changed, the imaging apparatus included outside the predetermined distance range in the captured image The resolution of the area in which the vicinity is imaged can be lowered.

[6] In the imaging device according to [4], the aperture amount calculation unit that calculates the aperture amount from the electrical signal converted by the image sensor, and the angle calculation unit, based on the calculated aperture amount, An angle of the image sensor with respect to the lens is calculated.
According to this, since the angle of the image sensor with respect to the lens can be calculated based on the aperture amount, the vicinity of the imaging device included outside the predetermined distance range in the captured image is captured even if the aperture amount is changed. The resolution of the area can be lowered.

  ADVANTAGE OF THE INVENTION According to this invention, the resolution of the area | region where the imaging device vicinity was imaged among the captured images can be reduced.

It is a functional block diagram of the imaging device in the 1st Embodiment of this invention. It is an example of the output image when the road condition ahead of a vehicle is image | photographed with the imaging device. It is the figure which showed the positional relationship of the lens and imaging device of the conventional imaging device. It is the figure which showed one example of the positional relationship of the lens and imaging device of the imaging device in the 1st Embodiment of this invention. It is a figure for demonstrating the positional relationship of the lens and imaging device of the imaging device in the 1st Embodiment of this invention. In the 1st Embodiment of this invention, it is a figure for demonstrating the angle of the image pick-up element with respect to a lens. It is a functional block diagram of the imaging device in the 2nd Embodiment of this invention. It is the figure which showed one example of the positional relationship of the lens and imaging device of the imaging device in the 2nd Embodiment of this invention. It is a figure for demonstrating the positional relationship of the lens and imaging device of the imaging device in the 2nd Embodiment of this invention. In the 2nd Embodiment of this invention, it is a figure for demonstrating the position of the image pick-up element with respect to a lens. It is a functional block diagram of the imaging device in the 3rd Embodiment of this invention. It is the flowchart which showed the flow of the process which changes the angle of the image pick-up element in the 3rd Embodiment of this invention. It is a functional block diagram of the imaging device in the 4th Embodiment of this invention. In the 4th Embodiment of this invention, when incident light is narrowed, it is a figure for demonstrating the inclination angle at the time of changing the inclination angle of the image pick-up element with respect to a lens. It is the flowchart which showed the flow of the process of the imaging device in the 4th Embodiment of this invention. It is the figure which showed one example of the attachment structure of the lens and imaging device of the conventional vehicle-mounted camera.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<First Embodiment>
First, a first embodiment of the present invention will be described. FIG. 1 is a functional block diagram of an imaging apparatus according to the first embodiment of the present invention. The imaging device 1 includes an optical unit 10 and a control unit 20. The optical unit 10 includes a lens holder 11, a lens barrel 12, six lenses 13 _i (i is an integer from 1 to 6), an image sensor 14, and an A / D converter 15.

The lens holder 11 holds the lens barrel 12. The lens barrel 12 holds each lens 13 _i . Each lens 13 _i condenses the light supplied from the subject and forms an image with the image sensor 14.

The image sensor 14 is attached to each lens 13 _i at a predetermined angle φ. The image sensor 14 converts the light collected by the lens 13 _i into an electric signal and supplies it to the A / D converter 15.
The A / D conversion unit 15 converts the supplied electric signal into digital image data, and stores the converted image data in a storage unit 21 described later of the control unit 20.

  The control unit 20 includes a storage unit 21 and an image processing unit 22. The image processing unit 22 reads out the image data stored in the storage unit 21, applies a predetermined filter to the read out image data as necessary, adjusts the luminance value, and performs projective transformation. . The image processing unit 22 supplies the image data after the image processing to an external device (not shown).

  FIG. 2 is an example of an output image when a road situation ahead of the vehicle is photographed by the imaging device. In the figure, a captured vehicle object is shown on the subject surface in front of the vehicle. A subject located a predetermined distance away from the subject surface is referred to as a far subject, and a subject located near a predetermined distance from the subject surface is referred to as a near subject.

Subsequently, a difference between the conventional imaging device and the imaging device of the present embodiment will be described.
FIG. 3 is a diagram illustrating a positional relationship between a lens and an imaging element of a conventional imaging device. Here, the depth of focus δ. In the figure, the light emitted from the intermediate subject A, the light emitted from the near subject B, and the light emitted from the far subject C are condensed by the lens, and the positions A ′ and B of the image sensor are respectively obtained. An image is formed at “position C”.

Since the position A ′ is in focus, the diameter of the circle of confusion, which is a circular image that the light from the light source joins on the image sensor, is almost zero. On the other hand, the position B ′ is out of focus, and the diameter of the circle of confusion in the neighborhood image is ε _b . Moreover, out of focus in the position C ', the diameter of the circle of confusion Tosobazo is epsilon _c. Also, the diameter ε _{b of the} circle of confusion in the near image is equal to the diameter ε _{c of the} circle of confusion in the far side image.

  FIG. 4 is a diagram illustrating an example of the positional relationship between the lens and the imaging element of the imaging device according to the first embodiment of the present invention. In the figure, the light emitted from the intermediate subject A, the light emitted from the near subject B, and the light emitted from the far subject C are collected by the lens, and the positions A ′, B ′, An image is formed at position C ′. The image sensor has a predetermined angle φ with respect to the lens.

The diameter ε _c of the distant circle of the distant image at the position C ′ is smaller than the diameter ε _a of the confusion circle of the intermediate image at the position A ′. Further, the diameter ε _a of the confusion circle of the intermediate image at the position A ′ is smaller than the diameter ε _b of the confusion circle of the neighboring image at the position B ′.
In the example of FIG. 4, the imaging element 14 is installed at a predetermined position and a predetermined inclination angle with respect to the lens such that the diameter of the circle of confusion increases as the subject approaches the imaging device.

Next, a method for calculating the tilt angle θ of the image sensor will be described using an example. FIG. 5 is a diagram for explaining the positional relationship between the lens and the imaging element of the imaging apparatus according to the first embodiment of the present invention. In the figure, the region between the far subject C and the intermediate subject A that are in focus is the in-focus region, and the region between the intermediate subject A and the near subject B that is not in focus is the out-of-focus region. Further, the in-focus distance, which is the in-focus distance from the lens of the subject A, is f _A , the in-focus distance of the subject B is f _B , and the in-focus distance of the subject C is f _C.

Here, assuming that the focal point (focusing) distance f, the allowable confusion circle diameter ε, and the lens effective aperture diameter D, the focal depth δ is calculated by the following equation (1).
δ = f × ε / D (1)
The allowable confusion circle diameter ε is, for example, the length of one pixel.

As an example, the effective lens diameter D is 2 [mm], the allowable circle of confusion ε is 5 [μm], the distance from the subject C to the lens is 100 [m], and the distance from the subject A to the lens is 50 [m]. When the distance from the subject B to the lens is B = 20 [m], the in-focus distances are f _C = 3.99 [mm], f _A = 4.00 [mm], and f _B = 4.01, respectively. [Mm].
Then, from the above equation (1), the focal depths are δ _C = 9.975 [μm], δ _A = 10 [μm], and δ _B = 10.25 [μm], respectively, which are approximately ± 10 [μm]. Is the allowable focusing range from the focusing surface.

  FIG. 6 is a diagram for explaining the angle of the image sensor with respect to the lens in the first embodiment of the present invention. The in-focus range from the in-focus surface at position A ′, position B ′, and position C ′ is ± 10 [μm]. Then, as shown in the figure, the focusing range 61 at the position C ′ is within a range of ± 10 [μm] from the position C ′. Further, the focusing range 62 at the position A ′ is a range of ± 10 [μm] from the position A ′. Further, since the in-focus range at the position B ′ is a range of ± 10 [μm] from the position B ′, the out-of-focus range at the position B ′ is out of focus with the out-of-focus range 63 shown in FIG. The focal range 64.

  Since the distance from the far subject C to the intermediate subject A in FIG. 5 is an in-focus region, the inclination angle θ of the image sensor is calculated so as to focus at the position C ′ and the position A ′. Further, since the area from the near subject B to the lens in FIG. 5 is an out-of-focus area, the tilt angle θ of the image sensor is calculated so as not to focus at the position B ′.

  Specifically, for example, the range of the inclination angle θ of the imaging surface is calculated as follows. First, a case will be described in which the imaging element passes through a point 10 [μm] away from the position C ′ in order to focus the far subject C.

In FIG. 6, in order to focus the intermediate subject A, a line segment from a point 10 [μm] left from the position C ′ to a point 10 [μm] left from the position A ′. It is necessary that the image sensor is tilted to the right from 65. In addition, the imaging element is tilted to the left from the line segment 65 from the point 10 [μm] left from the position C ′ to the point 10 [μm] right from the position A ′. Need to be. Then, since the vertical distance between the position A ′ and the position C ′ is 2 [mm], the inclination angle θ of the imaging surface needs to satisfy the following condition (2).
10/2000 <tan θ <30/2000 (2)

On the other hand, in order to prevent the near subject B from being focused, a line from a point 10 [μm] to the left from the position C ′ to a point 10 [μm] to the left from the position B ′. The image sensor needs to be tilted to the left with respect to the minute 66. In addition, the imaging element is tilted to the right from the line segment 66 from the point 10 [μm] left from the position C ′ to the right 10 [μm] from the position B ′. Need to be. Then, since the vertical distance between the position B ′ and the position C ′ is 5 [mm], the inclination angle θ of the imaging surface needs to satisfy the following condition (3).
tan θ <20/5000 or tan θ> 40/5000 (3)

  In order to prevent the intermediate subject A from being in focus and the nearby subject B from being in focus, the inclination angle θ of the imaging surface needs to satisfy the expressions (2) and (3). Solving Equation (2) and Equation (3), the range of the inclination angle θ of the imaging surface is 0.458 [deg] <θ <0.859 [deg] (inclination angle 69a in FIG. 6).

Next, a case where the image sensor passes through a point 10 [μm] away from the position C ′ to the right will be described. In FIG. 6, in order to focus the intermediate subject A, a line segment from a point 10 [μm] to the right from the position C ′ to a point 10 [μm] to the left from the position A ′. It is necessary that the image sensor is tilted to the right from 67. In addition, the image sensor is tilted to the left from a line segment 67 from a point 10 [μm] to the right from the position C ′ to a point 10 [μm] to the right from the position A ′. Need to be. Then, since the vertical distance between the position A ′ and the position C ′ is 2 [mm], the inclination angle θ of the imaging surface needs to satisfy the following condition (4).
−10/2000 <tan θ <10/2000 (4)

On the other hand, in order to prevent the near subject B from being focused, a line from a point 10 μm to the right from the position C ′ to a point 10 μm to the left from the position B ′. It is necessary that the image sensor is tilted to the left from the minute 68. In addition, the imaging element is tilted to the right with respect to a line segment 68 from a point 10 [μm] to the right from the position C ′ to a point 10 [μm] to the right from the position B ′. Need to be. Then, since the vertical distance between the position B ′ and the position C ′ is 5 [mm], the inclination angle θ of the imaging surface needs to satisfy the following condition (5).
tan θ <0 or tan θ> 20/5000 (5)

  In order to prevent the intermediate subject A from being in focus and the nearby subject B from being in focus, the inclination angle θ of the imaging surface needs to satisfy Expressions (4) and (5). When Expression (4) and Expression (5) are solved, the range of the inclination angle θ of the imaging surface is −0.286 [deg] <θ <0 [deg] or 0.229 [deg] <θ <0.286. [Deg] (inclination angle 69b in FIG. 6).

As described above, in the imaging apparatus according to the first embodiment, the distance from the lens of the image (or the first circle of confusion) in which the light arriving from the subject in the in-focus area is connected to the imaging element is the focal length to the focal depth. The tilt angle of the image sensor is set in advance so that the distance is within a range from a short distance to a distance long from the focal distance to the focal depth.
In addition to the above condition, the distance from the lens of the image (or the second circle of confusion) that the light arriving from the subject in the out-of-focus area is connected to the imaging device is shorter than the focal length by the focal depth, The tilt angle of the image sensor is set in advance so that it is outside the range from the focal length to the distance longer by the focal depth.

  As described above, in the imaging device, the diameter of the first circle of confusion that the light coming from the subject within the predetermined distance range from the lens joins on the imaging device is smaller than the predetermined length, and the predetermined distance range from the lens. The distance from the lens and the angle with respect to the lens are determined such that the diameter of the second circle of confusion that the light arriving at the lens from a subject at an outside distance joins on the image sensor is equal to or greater than the predetermined length. The

  According to the first embodiment, the imaging apparatus can focus on a subject in a predetermined far area and can not focus on a subject in a predetermined nearby area. Therefore, it is possible to reduce the resolution of the area where the vicinity of the imaging device is captured in the captured image. This eliminates the need for filter processing for reducing the resolution in the vicinity of the image processing unit, thereby reducing the calculation processing in the image processing unit.

<Second Embodiment>
Subsequently, a second embodiment of the present invention will be described. FIG. 7 is a functional block diagram of the imaging apparatus according to the second embodiment of the present invention. Elements common to those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. The configuration of the imaging device 1b in FIG. 7 is obtained by changing the optical unit 10 to the optical unit 10b with respect to the configuration of the imaging device 1 in FIG. The configuration of the optical unit 10b in FIG. 7 is obtained by changing the image sensor 14 to the image sensor 14b with respect to the configuration of the optical unit 10 in FIG.

Since the imaging device 1b opens the lens aperture, the imaging device 1b does not have an aperture, and lowers the degree of focusing in the vicinity by adjusting the focal position to the far field depth (front of the focal depth). Thereby, the effect of a low pass filter can be given to the image which imaged the neighborhood.
The imaging device 14b is located is disposed in parallel with respect to each lens 13 _i, distance from the rear principal point minus the depth of focus [delta] from the focal length f (f-δ). The image sensor 14 b converts the light collected by the lens 13 _i into an electrical signal and supplies the signal to the A / D converter 15.

  FIG. 8 is a diagram illustrating an example of the positional relationship between the lens and the imaging element of the imaging apparatus according to the second embodiment of the present invention. In the figure, the light emitted from the intermediate subject A, the light emitted from the near subject B, and the light emitted from the far subject C are condensed by the lens, and the positions A ′ and B of the image sensor are respectively obtained. An image is formed at “position C”. The image sensor is located at a distance (f−δ) from the rear principal point of the lens and is installed in parallel to the lens.

The far-field confusion circle diameter ε _{c at the} position C ′ is almost 0, which is smaller than the intermediate image confusion circle diameter ε _a at the position A ′. Further, the diameter ε _a of the confusion circle of the intermediate image at the position A ′ is smaller than the diameter ε _b of the confusion circle of the neighboring image at the position B ′.
In the example of FIG. 8, the image sensor 14b is installed in parallel to the lens at a position away from the lens by a predetermined distance so that the diameter of the circle of confusion increases as the subject approaches the imaging device.

Next, a method for calculating the distance from the lens of the image sensor will be described using an example. FIG. 9 is a diagram for explaining the positional relationship between the lens and the imaging element of the imaging apparatus according to the second embodiment of the present invention. In the figure, the region between the far subject C and the intermediate subject A in focus is the in-focus region, and the region between the intermediate subject A and the near subject B that is not in focus is the out-of-focus region. The in-focus distance of the subject A is f _A , the in-focus distance of the subject B is f _B , and the in-focus distance of the subject C is f _C. The imaging element is located at a distance between the focusing distance f _B focusing distance f _A and the object B of the subject A from the lens.

  FIG. 10 is a diagram for explaining the position of the image sensor with respect to the lens in the second embodiment of the present invention. In the figure, an in-focus range 101 is a range where a distant subject is focused, and is a range of ± 10 [μm] from the position C ′. The in-focus range 102 is a range in which the intermediate subject is focused, and is a range of ± 10 [μm] from the position A ′. The out-of-focus range 103 and the out-of-focus range 104 are ranges in which the near subject is out of focus, respectively, and ranges from the position B ′ to the left by more than 10 [μm], and the position B It is a range that exceeds 10 [μm] to the right from the point '.

The lens diameter D is 2 [mm], the permissible circle of confusion ε is 5 [μm] per pixel, the distance from the subject C to the lens is 100 [m], and the distance from the subject A to the lens is 50 [m]. The distance of the subject B from the lens is 20 [m]. In this case, assuming that the focus distances are f _C = 3.99 [mm], f _A = 4.00 [mm], and f _B = 4.01 [mm], the focal depths are δ _B = 9.975, respectively. [Μm], δ _A = 10 [μm], and δ _C = 10.25 [μm]. For all of the subjects A, B, and C, about 10 [μm] is an allowable in-focus range from the in-focus surface.

  When the depths of focus of the subjects B and C are approximated to 10 [μm], the distance from the lens of the image sensor is 3 in order to focus on the subjects A and B and not on the subject C. 99 to 4.00 [mm]. FIG. 10 shows the installation range 105 of the image sensor in that case.

As described above, in the imaging apparatus according to the second embodiment, the position of the imaging element when the light coming from the subject in the in-focus area forms an image is a position that is away from the focal distance from the position corresponding to the focal distance. The position of the image sensor is set in advance so as to fall within the range up to.
In addition to the above conditions, the position of the image sensor when the light coming from the subject in the out-of-focus area forms an image does not fall within the range from the position corresponding to the focal length to the position away from the focal length. As described above, the position of the image sensor is set in advance.

  In other words, the imaging element has a diameter of a circle of confusion where light arriving at the lens from a subject within a predetermined distance range from the lens is smaller than a predetermined length and a distance outside the predetermined distance range from the lens. Are arranged so that the diameter of the circle of confusion connecting the light coming from the subject to the lens on the image sensor is not less than a predetermined length.

  According to the second embodiment, the imaging apparatus can focus on a subject in a predetermined far area, and can not focus on a subject in a predetermined nearby area. Therefore, it is possible to reduce the resolution of the area where the vicinity of the imaging device is captured in the captured image. This eliminates the need for filter processing for reducing the resolution in the vicinity of the image processing unit, thereby reducing the calculation processing in the image processing unit.

<Third Embodiment>
Subsequently, a third embodiment of the present invention will be described. In the third embodiment, an imaging apparatus that adjusts the angle of the imaging element when the depression angle of the imaging apparatus with respect to the ground is changed will be described. Adjusting the angle of the image pickup device is, for example, when the depression angle of the image pickup device is changed when changing the distance range from the vehicle observed by the image pickup device, or when the vehicle loaded with the image pickup device is loaded. This is useful when the vehicle height changes due to the change in weight, and as a result, the depression angle of the imaging device is changed.

  FIG. 11 is a functional block diagram of an imaging apparatus according to the third embodiment of the present invention. Elements common to those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. The configuration of the imaging device 1c in FIG. 11 is the same as the configuration of the imaging device 1 in FIG. 1, except that the optical unit 10 is changed to the optical unit 10c and the control unit 20 is changed to the control unit 20c.

11 is different from the configuration of the optical unit 10 in FIG. 1 in that the imaging element 14 is changed to an imaging element 14c, and an imaging element substrate 16, a fixing member 17, an actuator (driving unit) 18, and the like. Has been added.
The imaging element 14c is such that the predetermined angle φ with respect to each lens 13 _i, is mounted horizontally with respect to the image pickup device substrate 16. The image sensor 14 c converts the light collected by the lens 13 _i into an electrical signal and supplies it to the A / D converter 15.

  The image sensor substrate 16 supports the image sensor 14c. One end of the image pickup device substrate 16 is fixed to the lens holder 11 by a fixing member 17. The other end of the image sensor substrate 16 is joined to an actuator (drive unit) 18.

The actuator (drive unit) 18 adjusts its length by a drive signal supplied from a drive control unit 25 of the control unit 20c described later. As a result, the actuator (drive unit) 18 can change the inclination angle of the image sensor substrate 16 with respect to each lens 13 _i, so that the image sensor 14 c has a predetermined angle φ with respect to each lens 13 _i . Can be adjusted.

The control unit 20c in FIG. 11 is different from the control unit 10 in FIG. 1 in that the storage unit 21 is changed to a storage unit 21c, and an angle calculation unit 23, a movement amount calculation unit 24, and a drive control unit 25 are used. Is added.
The storage unit 21c stores image data supplied from the A / D conversion unit 15. The storage unit 21c stores current inclination angle information indicating the current inclination angle of the image sensor.

The angle calculation unit 23 calculates the tilt angle of the image sensor after the change from the depression angle information indicating the depression angle with respect to the ground of the imaging apparatus supplied from the angle adjustment apparatus (not shown) and the information of the range to be observed in advance. The angle calculation unit 23 supplies the changed tilt angle information indicating the calculated tilt angle φ ₂ of the changed image sensor to the movement amount calculation unit 24.
Movement amount calculating section 24 reads the current tilt angle information indicating the tilt angle phi ₁ of the current image sensor in the storage unit 21c is stored. The movement amount calculation unit 24 calculates the movement amount of the actuator (drive unit) 18 from the current inclination angle information and the changed inclination angle information indicating the changed inclination angle φ ₂ supplied from the angle calculation unit 23. Further, the movement amount calculation unit 24 updates the value of the current inclination angle information stored in the storage unit with the changed inclination angle information.

The movement amount Δx of the actuator (drive unit) 18 is calculated by the following equation (6).
Δx = L (tanφ ₂ −tanφ ₁ ) (6)
Here, L is a vertical distance between the fixing member 17 and the actuator (drive unit) 18. The movement amount calculation unit 24 supplies the calculated movement amount information to the drive control unit 25.

  The drive control unit 25 generates a control signal for moving the actuator (drive unit) 18 from the movement amount information supplied from the movement amount calculation unit 24 and supplies the control signal to the actuator (drive unit) 18. To do. Accordingly, the drive control unit 25 can move the actuator (drive unit) 18 by a predetermined movement amount.

FIG. 12 is a flowchart showing a flow of processing for changing the angle of the image sensor in the third embodiment of the present invention. First, the angle calculation unit 23 receives depression angle information indicating the depression angle with respect to the ground of the imaging device supplied from an angle adjustment device (not shown) (step S101). Then, the angle calculating unit 23 calculates the inclination angle phi ₂ after the change of the imaging device from depression information (step S102).

Next, the movement amount calculation unit 24 reads the current inclination angle information indicating the inclination angle φ ₁ of the image sensor read from the storage unit 21 and the changed inclination indicating the changed inclination angle φ ₂ supplied from the angle calculation unit 23. The amount of movement of the actuator (drive unit) 18 is calculated from the angle information (step S103).
Next, the drive control unit 25 generates a control signal for moving the actuator (drive unit) 18 by the movement amount from the movement amount of the actuator (drive unit) 18 and supplies the control signal to the actuator (drive unit) 18. (Step S104).

  Next, the actuator (driving unit) 18 moves the joining position of the actuator (driving unit) 18 and the image sensor substrate 16 according to the supplied control signal, and changes the tilt angle of the image sensor substrate 16 (step). S105). Thereby, the actuator (driving unit) 18 can change the inclination angle of the image sensor 14c. Above, this flowchart is complete | finished.

  According to the third embodiment, when the depression angle that is the angle of the imaging apparatus with respect to the ground is changed in order to change the shootable range, the imaging apparatus is configured to change the inclination angle of the imaging element according to the changed depression angle. Can be changed. As a result, the imaging apparatus can focus on a subject in a far region according to the depression angle, and can not focus on a subject in a predetermined nearby region. In the captured image, the resolution of the area where the vicinity of the imaging device is captured can be reduced. This eliminates the need for filter processing for reducing the resolution in the vicinity of the image processing unit, thereby reducing the calculation processing in the image processing unit.

  In addition, since the angle of the image sensor can be adjusted so as to maximize the resolution of the object regardless of the position in the depth of field, the object to be detected can be imaged clearly.

<Fourth Embodiment>
Subsequently, a fourth embodiment of the present invention will be described. In the fourth embodiment, an imaging apparatus that adjusts the angle of the imaging element when the aperture is changed will be described. Adjusting the angle of the image sensor is, for example, when reducing the amount of light arriving at the image sensor by reducing the aperture when the surrounding brightness becomes extremely bright when going out of the tunnel. Useful for.

  FIG. 13 is a functional block diagram of an imaging apparatus according to the fourth embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the element which is common in FIG. 11, and the specific description is abbreviate | omitted. The configuration of the imaging device 1d in FIG. 13 is obtained by changing the optical unit 10c to the optical unit 10d with respect to the configuration of the imaging device 1c in FIG. The configuration of the optical unit 10d in FIG. 13 is obtained by adding a diaphragm 19 to the configuration of the optical unit 10c in FIG.

Stop 19 adjusts the width of the light incident from the lens 13 ₆ based on the control signal supplied from the throttle control unit 27 of the control unit 20d to be described later, it guides the light width is adjusted to the image pickup device 14c.
The configuration of the control unit 20d in FIG. 13 is different from the configuration of the optical unit 20c in FIG. 11 in that the image processing unit 22 is changed to the image processing unit 22d, the angle calculation unit 23 is changed to the angle calculation unit 23d, and the aperture amount is changed. A calculation unit 26 and an aperture control unit 27 are added.

  The image processing unit 22d reads the image data stored in the storage unit 21, applies a predetermined filter to the read image data as necessary, adjusts the luminance value, and performs projective transformation. . The image processing unit 22d supplies the image data after the image processing to the aperture amount calculation unit 26 and an external device (not shown).

The aperture amount calculation unit 26 calculates the aperture amount using a predetermined relational expression from the luminance value of the image data after image processing supplied from the image processing unit 22d. The aperture amount calculation unit 26 supplies the calculated aperture amount to the angle calculation unit 23 d and the aperture control unit 27.
The aperture control unit 27 generates a control signal for moving the aperture 19 by the aperture amount based on the aperture amount supplied from the aperture amount calculation unit 26, and supplies the control signal to the aperture 19. Thereby, the aperture control unit 27 can move the aperture 19 by a predetermined aperture amount.

The angle calculation unit 23 d calculates the tilt angle of the image sensor based on the aperture amount supplied from the aperture amount calculation unit 26, and supplies the tilt angle information indicating the tilt angle to the movement amount calculation unit 24. The tilt angle calculation method will be specifically described.
FIG. 14 is a diagram for explaining the tilt angle when changing the tilt angle of the image sensor with respect to the lens when the incident light is reduced in the fourth embodiment of the present invention. In the figure, a lens 141, an image sensor 142 before the aperture is reduced, and an image sensor 143 after the aperture is reduced are shown.

The light indicated by the solid line 144 before the aperture stop generates a circle of confusion with a diameter indicated by the arrow 145 in the image sensor 142 before the aperture stop. On the other hand, the light indicated by the broken line 146 after the aperture is reduced generates a circle of confusion with a diameter indicated by the arrow 147 in the image sensor 143 after the aperture is reduced.
The angle calculation unit 23d calculates the tilt angle of the image sensor so that the diameter of the circle of confusion indicated by the arrow 145 is the same as the diameter of the circle of confusion indicated by the arrow 147.

FIG. 15 is a flowchart showing a flow of processing of the imaging apparatus according to the fourth embodiment of the present invention. First, the lens 13 _i condenses the light emitted from the subject on the image sensor, and the image sensor converts the collected light into an electrical signal (step S201). Next, the A / D conversion unit 15 converts the electrical signal supplied from the image sensor into digital image data, and stores the image data in the storage unit 21 (step S202).

  Next, the image processing unit 22d performs predetermined image processing, and supplies the image data after the image processing to the aperture amount calculation unit 26 (step S203). The aperture amount calculation unit 26 calculates the aperture amount from the luminance value of the image data after image processing supplied from the image processing unit 22d using a predetermined relational expression, and sets aperture amount information indicating the aperture amount to the aperture control unit. 27 (step S204).

Next, the aperture control unit 27 generates a control signal based on the aperture amount information supplied from the aperture amount calculation unit 26 and supplies the control signal to the aperture 19 to move the aperture 19 by the aperture amount. (Step S205).
Then, the angle calculating unit 23d, based on supplied from the throttle amount calculating unit 26 diaphragm amount information, and calculates the inclination angle phi ₂ after the change of the imaging device, changing showing the inclination angle phi ₂ after the change The rear inclination angle information is supplied to the movement amount calculation unit 24 (step S206).

Next, the movement amount calculating section 24, and the current tilt angle information indicating the tilt angle phi ₁ of the imaging device read from the storage unit 21, changes indicating a tilt angle phi ₂ after the change, which is supplied from the angle calculation section 23d inclined The amount of movement of the actuator (drive unit) 18 is calculated from the angle information (step S207).
Next, the drive control unit 25 generates a control signal for moving the actuator (drive unit) 18 by the movement amount from the movement amount of the actuator (drive unit) 18 and supplies the control signal to the actuator (drive unit) 18. (Step S208).

  Next, the actuator (driving unit) 18 moves the joint position of the actuator (driving unit) 18 and the image sensor substrate 16 in accordance with the control signal supplied from the drive control unit 25, and the tilt angle of the image sensor substrate 16. Is changed (step S209). Thereby, the actuator (driving unit) 18 can change the inclination angle of the image sensor 14c. Above, this flowchart is complete | finished.

  According to the fourth embodiment, when the amount of light reaching the imaging device is adjusted by the diaphragm, the imaging device can change the inclination angle of the imaging device according to the diaphragm amount of the diaphragm. As a result, the imaging apparatus can focus on a subject in a far region according to the aperture amount, and can not focus on a subject in a predetermined nearby region. In the captured image, the resolution of the area where the vicinity of the imaging apparatus is captured can be lowered. This eliminates the need for filter processing for reducing the resolution in the vicinity of the image processing unit, thereby reducing the calculation processing in the image processing unit.

  As described above, the imaging apparatus of the present invention can focus on a subject in a far region and can not focus on a subject in a predetermined nearby region. In the image, the resolution of the area where the vicinity of the imaging device is imaged can be lowered.

  In the first embodiment, the third embodiment, and the fourth embodiment of the present invention, the inclination angle of the image sensor and the lens may be provided in a lens holder housing that holds the image sensor and the lens. When the image sensor is attached to the image sensor substrate, the image sensor may be attached to the image sensor substrate with an inclination angle.

  In the third embodiment and the fourth embodiment of the present invention, the image sensor has a predetermined angle with the lens in advance, and the angle of the image sensor is changed according to depression angle information or aperture amount information. However, the distance from the lens of the image sensor may be changed according to the depression angle information or the aperture amount information in parallel with the lens.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design etc. of the range which does not deviate from the summary of this invention are included.

1, 1b, 1c, 1d imaging device 10, 10b, 10c optical unit 11 lens holder 12 the lens barrel _{13 1,} 13 _{2, 13} 3, 13 _4, 13 5, 13 ₆ lens 14,14b imaging device 15 A / D Conversion unit 16 Image sensor substrate 17 Fixing member 18 Actuator (drive unit)
19 Apertures 20, 20c, 20d Control unit 21 21c Storage unit 22 22d Image processing unit 23 23d Angle calculation unit 24 Movement amount calculation unit 25 Drive control unit 26 Aperture amount calculation unit 27 Aperture control unit

Claims (6)

A lens that collects the light;
An image sensor that converts light collected by the lens into an electrical signal;
With
In the imaging element, a diameter of a first circle of confusion that is formed on the imaging element by light arriving at the lens from a subject within a predetermined distance range from the lens is smaller than a predetermined length, and the predetermined distance from the lens The distance from the lens and the angle with respect to the lens are such that the diameter of the second circle of confusion that the light arriving at the lens from a subject outside the distance range is connected to the image sensor is greater than or equal to the predetermined length. An imaging apparatus characterized by being determined.   From the lens of the second circle of confusion, the distance from the lens of the first circle of confusion is within a range from a short distance from the focal length to the focal depth to a long distance from the focal length to the focal depth. The imaging element forms an angle that is not parallel to the lens so that the distance is out of the range from the short distance from the focal distance to the long distance from the focal distance to the long distance from the focal distance. The imaging apparatus according to claim 1.   2. The imaging device according to claim 1, wherein a distance from the lens is parallel to the lens in a range from a focal distance of the lens to a distance shorter than a focal distance of the lens by a focal depth. Imaging device. A drive unit that moves one end of the image sensor to change the angle of the image sensor;
An angle calculator that calculates an angle of the image sensor with respect to the lens;
A movement amount calculation unit that calculates a movement amount of one end of the imaging element based on the calculated angle;
A drive control unit that controls the drive unit so that one end of the imaging element moves the calculated movement amount;
The imaging apparatus according to claim 1, further comprising:   The imaging apparatus according to claim 4, wherein the angle calculation unit calculates an angle of the imaging element with respect to the lens based on depression angle information indicating an depression angle of the apparatus with respect to the ground supplied from the outside. An aperture amount calculation unit that calculates an aperture amount from an electrical signal converted by the image sensor;
The imaging apparatus according to claim 4, wherein the angle calculation unit calculates an angle of the imaging element with respect to the lens based on the calculated aperture amount.

Images