JP2006211367A - Wide angle imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-sized imaging device with wide angle view. <P>SOLUTION: A reflective mirror having a reflective face with a curved surface shape, an imaging optical system including an image-focusing lens for receiving light reflected by the reflective face and forming an optical image, and an imaging element arranged opposite to the image-focusing lens for converting the optical image which is focused as an image by the imaging optical system, to an electric image signal and generating as an output are provided. A unit is constituted by the image-focusing lens and an imaging region, on the imaging element having two or more light receiving units for receiving an optical image formed by the image-focusing lens, and two or more units are arranged in two dimensional way so image information in directions of 360° of the environment of the device, can be acquired at once. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging apparatus for photographing a wide angle of view, and more particularly to a miniaturized wide-angle imaging apparatus that photographs an image reflected by a reflecting mirror.

  In recent years, image input devices capable of inputting a wide range of visual information have been studied. These are expected to be applied to mobile robots, monitoring devices, and the like, and among them, image input devices that can acquire a large amount of visual information at once are being researched.

  As such an image input device, a wide-angle imaging device capable of acquiring image information in a 360 ° direction around the device (hereinafter referred to as an omnidirectional image) at a time has been proposed. An apparatus using a rotating mirror is known as one of these wide-angle imaging devices. This device is composed of a rotator mirror having a reflecting surface installed vertically downward, and an imaging device installed in a vertically downward direction of the rotator mirror, and subject light reflected by the rotator mirror is captured by the imaging device. Take an image. Thereby, it is possible to acquire an omnidirectional image at a time. However, a wide-angle imaging device using a cone or a spherical surface as the shape of the rotating mirror generates large aberrations due to the shape of the rotating mirror, so that the image quality of the captured image is low and the captured image is distorted. There was a problem that it was difficult to see.

  On the other hand, a wide-angle imaging device in which the shape of the rotating mirror is a paraboloid or hyperboloid has been proposed (Patent Document 1). As an example, a wide-angle imaging device using a hyperboloid mirror will be described. FIG. 10 is a schematic diagram showing a configuration of a wide-angle imaging device using a hyperboloid mirror. The wide-angle imaging device 500 includes a hyperboloid mirror 501 having a rotational axis symmetry shape, an imaging lens 502, and an imaging element 503. Here, the rotation center axis of the hyperboloid mirror 501 is taken as the Z axis. Also, in the plane perpendicular to the Z axis, the orthogonal axes are the X axis and the Y axis, respectively.

  The wide-angle imaging device 500 uses one of the two leaf hyperbolas as a reflecting mirror. As shown in FIG. 11, the two-leaf hyperboloid has two focal points 504a and 504b. The focal point 504 a is a hyperboloid focal point used as the hyperboloidal mirror 501. On the other hand, the focal point 504b is the focal point of the other hyperboloid of the two-leaf hyperboloid. The hyperboloid mirror 501 has a property that the shape of the cut surface by the ZY plane is a hyperbola, and the shape of the cut surface by the XY plane is a circle.

  The imaging lens 502 forms an optical image of the subject on the image sensor 503. The imaging lens 502 is installed so that the position of the principal point 507 of the imaging lens 502 is equal to the position of the hyperboloid focal point 504b.

  As shown in FIG. 10A, a light beam from an arbitrary point P in the YZ plane enters the focal point 504a. The light beams 508a and 508b incident on the hyperboloid mirror 501 are reflected on the reflection surface and then condensed on the principal point 507. The principal point 507 is located at the same position as the focal point 504b of the other hyperboloid of the two-leaf hyperboloid. As shown in FIG. 10B, the light beam focused on the principal point 507 is imaged on the imaging surface 505 of the imaging element 503 by the imaging lens 502. At this time, the light beams 508a and 508b are imaged at imaging points 510a and 510b on the imaging surface 505 of the imaging element 503, respectively.

  As described above, the wide-angle imaging device using the hyperboloidal mirror is configured so that the main point of the imaging lens and the focal point of the hyperboloid are configured at the same position, so that the extension of the light flux from an arbitrary point P is two-leafed. Among the hyperboloids, an optical system that passes through the focal point of the other hyperboloid of the hyperboloidal mirror can be configured. As a result, the image formed on the imaging surface can be converted into a coordinate system centered on the focal point of the hyperboloidal mirror. Therefore, a wide-angle imaging device using a hyperboloid mirror can form an image in the direction of 360 ° around the rotation axis of the hyperboloid mirror on the imaging surface at a time.

  In addition, a wide-angle imaging device using a paraboloidal mirror, like a hyperboloid, has a paraboloid having a focal point, so that the image formed on the imaging surface is centered on the focal point of the parabolic mirror. Conversion to a system is possible. Therefore, an image in the direction of 360 ° around the rotation axis of the parabolic mirror can be formed on the imaging surface at a time.

  On the other hand, in recent years, with the miniaturization of electronic devices and portable devices, imaging devices that can be mounted on these devices are required. However, the conventional imaging apparatus using a single optical system is configured by combining a plurality of lenses in the optical axis direction in order to suppress the occurrence of aberration and ensure a certain optical performance. Yes. Therefore, there is a limit to reducing the size and weight of a conventional imaging device using a single optical system.

On the other hand, an imaging apparatus including an optical system imitating a compound eye structure possessed by insects has been proposed (Patent Document 2 or Patent Document 3). An image pickup apparatus including such a compound eye optical system includes a lens array having a plurality of photographing lens units, and an image pickup element on a plane disposed to face the lens array. An entire image can be obtained by forming a partial image of the subject in a predetermined area on the image sensor with the photographic lens unit and synthesizing these partial images. Thereby, the distance between the imaging lens and the image sensor can be shortened, and the size and weight can be reduced as compared with an image pickup apparatus using a single optical system.
Japanese Patent No. 2939087 JP 2001-5054 A JP 2002-171537 A

  In the wide-angle imaging device 500 using the hyperboloid mirror, the position where the virtual image of the subject is formed changes depending on the shape of the hyperboloid mirror 501. As shown in FIG. 12, the light beam emitted from the object 511 a is reflected on the hyperboloid mirror 501 and then imaged on the imaging surface 505 of the imaging element 503 via the imaging lens 502. In addition, a virtual image 511b of the object 511a is formed by the hyperboloid mirror 501. The distance from the position where the virtual image 511b is formed to the image sensor 503 is the distance from the object 511a to the hyperboloidal mirror 501 or the radial position where the light beam emitted from the object 511a enters the hyperboloidal mirror 501, that is, the hyperboloidal mirror. Depends on the shape of the. Therefore, the wide-angle imaging device 500 using the hyperboloidal mirror requires the imaging lens 502 with a deep depth of field in order to be able to focus the entire field of the imaging element 503 on the virtual image 511b.

  However, in order to obtain a deep depth of field, it is necessary to increase the distance between the imaging lens 502 and the imaging element 503 and the distance between the imaging lens 502 and the hyperboloid mirror 501. Therefore, it is difficult for the wide-angle imaging device 500 to shorten the overall length of the optical system. Further, the diameter of the hyperboloid mirror 501 depends on the distance between the imaging lens 502 and the hyperboloid mirror 501, that is, the incident angle of the light beam incident on the imaging lens 502, and thus it is difficult to reduce the size of the wide-angle imaging device as a whole. There was a problem of being. Further, since the curvature of the cross section of the hyperboloid mirror 501 is different between the XY cross section and the ZY cross section, there is a problem that the virtual image is not tied to one point and the image quality of the captured image is deteriorated.

  A wide-angle imaging device using a parabolic mirror has a property that a principal ray of a light beam emitted from an object and reflected on the parabolic mirror is parallel to the optical axis of each imaging lens. However, the light receiving system in which these parallel projections are established cannot be realized by the conventional wide-angle imaging device and optical system, and the captured image can be accurately converted into an image centered on the paraboloid focus. There wasn't.

  On the other hand, the image pickup apparatus including the compound eye optical system described in Patent Document 2 and Patent Document 3 is reduced in size by reducing the diameter of the imaging lens and shortening the distance between the imaging lens and the imaging element. I am trying. However, it has not been proposed to shorten the total length of the optical system including the distance between the subject and the imaging lens and the distance between the imaging lens and the image sensor. In addition, there is no proposal for downsizing the entire image pickup apparatus in combination with other optical systems.

  Accordingly, an object of the present invention is to provide a wide-angle imaging device capable of obtaining a clear omnidirectional image with reduced image quality while reducing the size of the entire device including the optical system in order to solve the above problems. There is.

The object of the present invention is achieved by a wide-angle imaging device having the following configuration.
An imaging apparatus capable of outputting an optical image of a subject as an electrical image signal,
A reflecting mirror having a curved reflecting surface;
An imaging optical system including an imaging lens that receives the light reflected by the reflecting surface and forms an optical image;
An optical image formed by the imaging optical system is converted into an electrical image signal and output, and includes an imaging device disposed opposite to the imaging lens.
A unit is constituted by an imaging lens and an imaging region on an imaging device having a plurality of light receiving portions that receive an optical image formed by the imaging lens,
A plurality of units are two-dimensionally arranged.

  With this configuration, the distance between the imaging element and the imaging lens and the distance between the reflection mirror and the imaging lens can be shortened. Along with this, the reflecting mirror can also be made small, so that a miniaturized wide-angle imaging device can be provided.

  As an example, the reflecting mirror includes a convex mirror having a parabolic shape.

  With this configuration, the light beam reflected by the parabolic mirror enters each imaging lens as parallel light and forms an image on the image sensor. As a result, the captured image can be easily converted into an image centered on the focal point of the paraboloid, so that it is possible to provide a miniaturized wide-angle imaging device with a short overall optical system length.

Specifically, an image synthesizer that generates an image signal of a subject image based on a plurality of image signals output by the image sensor,
The image synthesizer is characterized in that it generates an image signal of a subject image centered on the paraboloidal focus based on a plurality of image signals output by a plurality of units.

  With this configuration, the partial image of the subject output for each unit is combined into a single whole image with the focal point of the parabolic mirror as the center of the visual field.

  As an example, the reflecting mirror includes a convex mirror having a shape of one of the two leaf hyperboloids.

  With this configuration, the captured image can be converted into an image centered on the focal point of the hyperboloid mirror.

As a specific example, the imaging optical system includes a deflecting element that makes light having an angle of view corresponding to the arrangement position of the imaging lenses out of the light reflected by the reflecting surface,
The principal ray of light reflected by the reflecting surface and incident on the image sensor passes through the focal point of the other hyperboloid of the two-leaf hyperboloid.

  With this configuration, the light beam reflected by the hyperboloid mirror is imaged on the image sensor by the lens array including a plurality of imaging lenses. As a result, the captured image can be easily converted into an image centered on the focal point of the hyperboloidal mirror, so that it is possible to provide a compact and wide-angle imaging device with a short overall optical system length. In addition, by using an imaging lens with a small diameter, the reflection area of the hyperboloidal mirror can be reduced, so that the displacement of the position where the virtual image is formed becomes minute and the omnidirectional image in which the deterioration of the image quality is suppressed. Can be obtained.

As a specific example, an image synthesizer that generates an image signal of a subject image based on a plurality of image signals output by an image sensor,
The image synthesizer is characterized in that it generates an image signal of a subject image with the focus of the reflection mirror as the center of the visual field based on a plurality of image signals.

  With this configuration, the partial image of the subject output for each unit is combined into a single whole image with the focal point of the hyperboloid mirror as the center of the visual field.

  As a specific example, the deflection element is characterized by comprising a lens.

  With this configuration, since the light beam incident on each imaging lens is refracted into parallel light, a field of view for the subject can be secured, and the imaging lens can be arranged on a plane.

  As a specific example, the deflection element is characterized by comprising a Fresnel lens.

  With this configuration, in addition to the effect of securing the field of view for the subject, the thickness of the lens can be reduced, so that the size can be further reduced in the optical axis direction.

  As described above, it is possible to provide a wide-angle imaging device capable of obtaining a clear omnidirectional image in which deterioration of image quality is suppressed while reducing the size of the entire device including the optical system.

(Embodiment 1)
FIG. 1 is a schematic diagram illustrating a configuration of a wide-angle imaging device 100 according to the first embodiment. The wide-angle imaging device 100 includes a parabolic mirror 1, a lens array 3, an imaging element 4, an A / D converter 12, and an image synthesizer 13.

  The parabolic mirror 1 is a convex mirror having a reflecting surface, and has a curved surface shape obtained by rotating a parabola having a focal point 5 around an axis. As shown in FIG. 1, the rotation center axis 6 of the parabolic mirror 1 coincides with the Z axis indicating the vertical direction. Also, in the plane perpendicular to the Z axis, the orthogonal axes are the X axis and the Y axis, respectively. The parabolic mirror 1 has a property that the shape of the cut surface by the ZY plane is a parabola and the shape of the cut surface by the XY plane is a circle.

  The lens array 3 is composed of a plurality of minute imaging lenses, and is disposed to face the image sensor 4. In the present embodiment, the lens array 3 is configured by a total of 25 imaging lenses, each having 5 in the X direction and 5 in the Y direction, in a single plane. The light beam incident on the lens array 3 is imaged on the image sensor 4 by the refraction action of the imaging lens.

  The image sensor 4 is a CCD (Charge Coupled Device), and converts an optical image formed by the imaging lens into an electrical signal. On the image sensor 4, a plurality of light receiving portions for taking in incident light flux are formed. Furthermore, the imaging element 4 has the same number of imaging regions as the number of imaging lenses, and one imaging region includes a plurality of light receiving units. Here, each imaging optical system is a unit, and one unit includes one imaging lens and one imaging region. These plural units are arranged two-dimensionally. As a result, the light beam incident on one imaging lens is imaged on one imaging region and converted into an electrical analog signal. The image sensor 4 may be a CMOS (Complementary Metal-Oxide Semiconductor).

  The A / D converter 12 converts the analog signal output from the image sensor 4 into a digital signal. The image synthesizer 13 performs a synthesis process, which will be described later, on the image signal output from the A / D converter 12.

Of the luminous flux emitted from the object 11 a, the luminous flux 8 whose chief ray is directed to the focal point 5 of the parabolic mirror 1 is reflected on the reflecting surface of the parabolic mirror 1. The principal ray of the light beam 8 is reflected so as to be parallel to the Z axis due to the nature of the parabolic mirror 1. Thereafter, the reflected light beam 8 enters the lens array 3 and forms an image for each unit. With this configuration, the principal ray of the light beam 8 reflected on the parabolic mirror 1 is incident on each imaging lens of the lens array 3 as parallel light regardless of the position of the object 11a. Can be converted to a coordinate system centered on 5.

  Next, an image obtained by the wide-angle imaging device according to the present embodiment will be described. In FIG. 2, a screen 20 on which four characters “a”, “b”, “c”, and “d” are drawn is installed around the parabolic mirror 1 around the Z axis. Moreover, as shown in FIG.2 (c), the screen 20 is installed so that the distance from the surface to the parabolic mirror 1 may become fixed.

  FIG. 3 shows a virtual image of the screen 20 formed by the parabolic mirror 1. The virtual image formed at this time is an image in which characters drawn on the screen 20 are relatively inverted. A light beam 8 from the screen 20 toward the focal point 5 of the parabolic mirror 1 is reflected on the parabolic mirror 1. The light beam 8 reflected so that the principal ray is parallel to the Z axis enters the lens array 3 and is imaged on the image sensor 4 by each imaging lens. At this time, each imaging lens forms a partial image of the virtual image of the screen 20 on the image sensor 4. For example, as shown in FIG. 4, in the unit A11, the virtual image of the area A11 is imaged on the imaging area A11 on the imaging element 4 by the imaging lens A11. Therefore, when 25 imaging lenses are used, 25 units are configured, and the imaging region of the screen 20 is divided into 25. Further, an inverted image of the partial image is formed on the image sensor 4 by the image forming action of the image forming lens. Each image formed on the image sensor 4 is converted into an electrical analog signal by the CCD, and then converted into a digital signal by the A / D converter 12.

  FIG. 5 shows a diagram in which each partial image obtained by each unit is reconstructed. The partial image output by each unit is converted into a digital signal by the A / D converter 12 and then combined by the image combiner 13. The image synthesizer 13 includes a rotation processing circuit and a composition processing circuit, and forms a composite image by performing rotation processing and composition processing on each partial image shown in FIG. The image synthesizer 13 first performs a process of converting each partial image output from the A / D converter 12 from an inverted image to an erect image. That is, the image is rotated by 180 ° about the center of each photographing region, and these are combined to output a combined image as one whole image. At this time, since the imaging ranges of the adjacent imaging lenses partially overlap, the partial images are connected using a pattern matching method such as a well-known correlation process by using the overlapping part. The combined composite image is recorded on a recording device or displayed on a monitor.

  Thus, the compound eye optical system using the parabolic mirror and the plurality of imaging lenses can shorten the distance between the imaging element and the imaging lens and the distance between the parabolic mirror and the imaging lens. The size can be reduced in the optical axis direction. Further, since the distance between the paraboloid mirror and the imaging lens is shortened, the paraboloid mirror can also be made small, so that the entire wide-angle imaging device can be downsized. Furthermore, since the diameter of each imaging lens is very small, the displacement of the position where the virtual image is formed becomes small, and deterioration in image quality can be suppressed.

  As described above, by using the wide-angle imaging device according to the first embodiment, the principal ray of the light beam reflected by the parabolic mirror is parallel to the rotation axis of the parabolic mirror. It can be converted into an image centered on the focus of the parabolic mirror. Further, in the compound eye optical system, since the diameter of the imaging lens is very small, the position of the principal point can be shifted compared to the case where one imaging lens is used in a single optical system. As a result, the back focus can be shortened and the size can be reduced in the optical axis direction.

  Each imaging lens forms a partial image of the virtual image on the image sensor for each unit. Then, the entire image is obtained by synthesizing the partial images from each unit. Therefore, the partial image obtained by each unit has a low resolution, so that it can be pan-focused, and the distance between the lens array and the parabolic mirror can be shortened. Therefore, since the distance between the imaging lens and the imaging element and the distance between the imaging lens and the parabolic mirror, that is, the total length of the optical system can be shortened, a miniaturized wide-angle imaging device can be provided. .

  Further, since the diameter of the imaging lens is very small, the reflection area of the parabolic mirror for the light beam incident on each imaging lens becomes small. Therefore, the displacement of the virtual image forming position due to the difference in the curvature of the cross section of the parabolic mirror can be made minute. Thereby, it is possible to obtain a clear omnidirectional image in which deterioration of image quality is suppressed.

  In the present embodiment, the shape of the reflecting mirror is a paraboloid, but is not limited thereto. For example, it is possible to capture an omnidirectional image using a rotationally symmetric conical shape that can reflect subject light so that it becomes parallel light to the imaging lens, or a rotationally asymmetrical mirror. A wide-angle imaging device can be configured.

(Embodiment 2)
FIG. 6 is a schematic diagram illustrating a configuration of the wide-angle imaging device 200 according to the second embodiment. The wide-angle imaging device 200 has a configuration that is substantially the same as the configuration of the wide-angle imaging device 100 according to Embodiment 1, but differs in the following points. That is, the difference is that the shape of the rotating mirror is a hyperboloid, and a deflection element is provided on the hyperboloid mirror side of the lens array 3.

  The bilobal hyperboloid has two focal points 25 and 27. One of the two leaf hyperboloids having the focal point 25 is used as the hyperboloidal mirror 21. The hyperboloid mirror 21 is a convex mirror having a reflecting surface. Here, the rotation center axis 26 of the hyperboloid mirror 21 coincides with the Z axis indicating the vertical direction. Also, in the plane perpendicular to the Z axis, the orthogonal axes are the X axis and the Y axis, respectively. The hyperboloid mirror 21 has a property that the shape of the cut surface by the ZY plane is a hyperbola and the shape of the cut surface by the XY plane is a circle.

  The deflecting optical element includes a plano-convex lens 22 and refracts the incident light beam so as to become parallel light with respect to the imaging lens of the lens array 3. As a result, the light beam reflected by the hyperboloid mirror 21 can be made incident on the imaging lens positioned around the end of the lens array 3, and a field of view for the subject can be secured. The plano-convex lens 22 is arranged so that the positions of the focal point 7 of the hyperboloid and the focus of the plano-convex lens are equal. Therefore, the principal ray of the light beam reflected by the hyperboloid mirror 21 and incident on the plano-convex lens 22 passes through the focal point of the other hyperboloid of the two-leaf hyperboloid. The light beam incident as the parallel light is imaged on the image sensor 4 by each imaging lens constituting the lens array 3.

  Of the luminous flux emitted from the object 11 a, the luminous flux 28 whose chief ray is directed to the focal point 25 of the hyperboloidal mirror 21 is reflected on the reflecting surface of the hyperboloidal mirror 21, and then the focal point 27 of the hyperboloid on the rotation center axis 26. To reach. The light beam 28 that has reached the focal point 27 is converted into parallel light by the plano-convex lens 22 and then enters the lens array 3. The luminous flux 28 incident on the lens array 3 is imaged for each unit by the imaging lens. With such a configuration, the principal ray of the light beam reflected on the hyperboloidal mirror 21 reaches the focal point 27 of the hyperboloid and plano-convex lens regardless of the position of the object 11a. Can be converted to the coordinate system.

  Next, an image obtained by the wide-angle imaging device according to the present embodiment will be described. As in the first embodiment, in FIG. 2, the screen 20 on which four characters “a”, “b”, “c”, and “d” are drawn is installed around the hyperboloid mirror 21 around the Z axis. The At this time, as in the first embodiment, the screen 20 is installed such that the distance from the surface to the hyperboloid mirror 21 is constant.

  The virtual image formed by the hyperboloid mirror 21 becomes an image with less distortion of characters compared to the case where the parabolic mirror in the first embodiment is used. A light beam 28 which is reflected on the hyperboloid mirror 21 and whose principal ray reaches the focal point 27 is refracted into parallel light by the plano-convex lens 22 having a focal point at the same position as the hyperboloid focal point 27. The light beam 28 refracted by the parallel light enters the lens array 3 and forms an image on the image sensor 4. Here, as in the first embodiment, each imaging lens constituting the lens array 3 is very small, so that a partial image of the screen 20 is imaged for each unit. At this time, an erect image of the partial image is formed on the image sensor 4 by the imaging action of the plano-convex lens and the imaging lens.

  FIG. 7 shows a diagram in which each partial image obtained by each unit is reconstructed. Unlike the case of the first embodiment, since the captured image is an erect image, the image synthesizer 13 does not require a rotation processing circuit. Therefore, as compared with the first embodiment, it is possible to reduce the load of signal processing in the image synthesizer 13. The image synthesizer 13 performs a synthesis process using a known pattern matching method such as a correlation process, and outputs a synthesized image signal as one whole image.

  Thus, by the compound eye optical system using the hyperboloid mirror and a plurality of imaging lenses, the distance between the imaging element and the imaging lens and the distance between the hyperboloid mirror and the imaging lens can be shortened. Miniaturization in the optical axis direction is possible. In addition, by shortening the distance between the paraboloidal mirror and the imaging lens, the hyperboloidal mirror can also be made small, so that the entire wide-angle imaging device can be miniaturized. Furthermore, since the diameter of each imaging lens is very small, the displacement of the position where the virtual image is formed becomes small, and deterioration in image quality can be suppressed.

  As described above, the wide-angle imaging device according to the second embodiment can be downsized in the optical axis direction as in the first embodiment even when a hyperboloid mirror that has been difficult to downsize is used. Become. Moreover, since the diameter of the hyperboloidal mirror can be reduced by shortening the distance between the imaging lens and the hyperboloidal mirror, a further miniaturized wide-angle imaging device can be obtained. In addition, since the reflection region of the light beam in the hyperboloid mirror can be reduced, an omnidirectional image in which deterioration of image quality is suppressed can be obtained. Therefore, even in a wide-angle imaging device using a hyperboloid as the shape of the rotator mirror, it is possible to reduce the size and suppress deterioration in image quality.

  Further, in the wide-angle imaging device according to the second embodiment, since the captured image is an erect image, it is possible to provide an image synthesizer that does not require a rotation processing circuit and has a low signal processing load. A wide-angle imaging device can be obtained.

  In the second embodiment, a plano-convex lens is used as the deflecting optical element, but the present invention is not limited to this. For example, as shown in FIG. 8, you may use the Fresnel lens which has an effect equivalent to a plano-convex lens. Thereby, compared with the case where a plano-convex lens is used, the thickness of the lens can be reduced, and further downsizing in the optical axis direction is possible.

  In Embodiments 1 and 2, as shown in FIG. 9, a partition wall may be provided as a light shielding plate between the lens array and the imaging element. Thereby, it is possible to prevent an image formed by each imaging lens constituting the lens array from being input to the imaging element in an overlapping manner with an image formed by an adjacent imaging lens. Therefore, in addition to the effects of Embodiments 1 and 2, image quality deterioration can be further suppressed, and a good omnidirectional image signal can be obtained.

  In Embodiments 1 and 2, the imaging region is divided into 25, and the number of imaging lenses constituting the lens array is 25 in the X direction and 5 in the Y direction. I can't.

  The two-dimensional arrangement of units is not limited to a single plane as shown in the first and second embodiments, but may be on a virtual sphere.

  The wide-angle imaging device of the present invention is suitable for a monitoring device, a visual sensor of a mobile robot, an in-vehicle imaging device, and the like that are required to be downsized.

Schematic showing the configuration of the wide-angle imaging device according to the first embodiment FIG. 2 is a schematic diagram of an object to be photographed according to Embodiment 1, where (a) is a schematic diagram of the object to be photographed, and (b) and (c) are layout diagrams of the object to be photographed and a wide-angle imaging device. The figure which shows the virtual image projected on the parabolic mirror of the wide angle imaging device which concerns on Embodiment 1. FIG. 2A and 2B are diagrams illustrating a lens array and a shooting area according to Embodiment 1, where FIG. 3A is a diagram illustrating a shooting area for a virtual image, and FIG. The figure which reconfigure | reconstructed each partial image obtained by each unit which concerns on Embodiment 1. FIG. Schematic which shows the structure of the wide angle imaging device which concerns on Embodiment 2. FIG. The figure which reconfigure | reconstructed each partial image obtained by each unit which concerns on Embodiment 2. FIG. The figure which used the Fresnel lens for the deflection | deviation element which concerns on Embodiment 2. FIG. It is a figure which shows the wide angle imaging device provided with the light-shielding plate which concerns on Embodiment 1 and 2, (a) is a schematic sectional drawing which shows a structure, (b) is a figure which shows the relationship between an imaging region and a light-shielding plate. Schematic showing the configuration of a conventional wide-angle imaging device Diagram showing a two-leaf hyperboloid The figure which shows the virtual image formation which concerns on the conventional wide angle imaging device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Parabolic mirror 3 Lens array 4 Image pick-up element 5 Focal point 6 of a parabolic mirror Rotational center axis 8 of a parabolic mirror Light beam 9 Partition 11a Imaged object 11b Virtual image 12 A / D converter 13 Image synthesizer 14 Fresnel lens 15 Internal focal point 20 of parabolic mirror 20 Screen 21 Hyperboloid mirror 22 Plano-convex lens 25 Hyperboloid focal point 26 Rotational center axis of hyperboloidal mirror 27 Hyperboloid focal point 28

Claims (8)

An imaging apparatus capable of outputting an optical image of a subject as an electrical image signal,
A reflecting mirror having a curved reflecting surface;
An imaging optical system including an imaging lens that receives the light reflected by the reflecting surface and forms an optical image;
An optical image formed by the imaging optical system is converted into an electrical image signal and output, and includes an imaging device disposed facing the imaging lens.
A unit is constituted by the imaging lens and an imaging region on the imaging device having a plurality of light receiving portions that receive an optical image formed by the imaging lens,
A wide-angle imaging device, wherein the plurality of units are arranged two-dimensionally.   The wide-angle imaging device according to claim 1, wherein the reflection mirror includes a convex mirror having a parabolic shape. An image synthesizer that generates an image signal of a subject image based on the plurality of image signals output by the image sensor;
The image synthesizer generates an image signal of the subject image with a focal point being the focal point of the paraboloid, based on a plurality of the image signals output from the plurality of units. Item 3. The wide-angle imaging device according to Item 2.   The wide-angle imaging device according to claim 1, wherein the reflection mirror includes a convex mirror having a shape of one hyperboloid of two-leaf hyperboloids. The imaging optical system includes a deflection element that makes light having an angle of view corresponding to the arrangement position of the imaging lenses out of the light reflected by the reflection surface,
The wide-angle imaging device according to claim 4, wherein a principal ray of light reflected by the reflecting surface and incident on the imaging device passes through a focal point of the other hyperboloid of two leaf hyperboloids. An image synthesizer that generates an image signal of a subject image based on the plurality of image signals output by the image sensor;
The image synthesizer generates an image signal of the subject image with the focal point of the reflecting mirror as the center of the visual field based on the plurality of image signals output from the plurality of units. 4. The wide-angle imaging device according to 4.   The wide-angle imaging device according to claim 4, wherein the deflection element is a lens. The wide-angle imaging device according to claim 4, wherein the deflection element is a Fresnel lens.

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