JP2000131613A - Wide angle image optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extremely simply provide a wide angle image optical system which is suitable for wide-angle panoramic photographing or observation by combining a pair of reflection surfaces having a cylindrical surface or a shape closely similar to a cylinder, for example a toric surface, a toroidal surface, or a conical surface. SOLUTION: The wide angle image optical system includes 1st and 2nd cylindrical reflection surfaces 1 and 2, and they are arranged so that the curvature center axis of the 1st reflection surface 1 may be nearly orthogonal to the curvature center axis of the 2nd reflection surface 2, and the system is provided with an optical system 3 for forming light which is made incident on the 2nd reflection surface 2 and reflected by the surface 2 after being made incident on the 1st reflection surface 1 and reflected by the surface 1 into an image. It is allowed to make the 1st reflection surface 1 convex and to make the 2nd reflection surface 2 also convex. The 1st and 2nd cylindrical reflection surfaces 1 and 2 have the cylindrical surfaces, the toric surfaces, the toroidal surfaces and the gentle conical surfaces, etc., so as to compensate the image distortion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wide-angle image optical system formed by combining a pair of reflecting surfaces such as a toric surface, a toroidal surface, and a conical surface.

[0002]

2. Description of the Related Art There is a demand for monitoring a field of view with an ultra-wide angle of view, and a camera lens with an ultra-wide angle of view using a refractive optical system is used for this purpose. An ultra-wide angle camera lens is also called a fisheye lens. Normally, a fisheye lens requires about ten lenses, which is expensive and heavy, and is extremely large in distortion and can be used only for special photographing.

In panoramic photography, a method is known in which a slit-like opening is provided between a lens and a film, and the camera is rotated to expose and develop. This is because the camera itself is expensive, few companies make it, and it requires a great deal of effort to prepare for shooting.

In simple panoramic photography, there is a method of dividing the photographing area and taking a picture after development, and then joining the pictures with a digital camera. In the case of a digital camera, there is a method of joining them with software of a computer. There are deviations in the size, position, exposure situation, etc. of the subject in the above, and it is difficult to complete the work, which is very difficult.

In contrast to the above, an optical assembly for observing a panoramic scene using a spherical reflecting mirror has been proposed (Japanese Patent Laid-Open No. Hei 10-123422). However, since a large number of complicated mirror surfaces are used, Like the optical system described above, it is large and expensive.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a cylindrical surface or a shape close to a cylinder, for example, a toric surface.
An object of the present invention is to provide a wide-angle image optical system which is extremely simple but is suitable for photographing or observing a wide-angle panoramic image by combining a pair of reflecting surfaces such as a toroidal surface and a conical surface.

[0007]

In order to achieve the above object, a wide-angle image optical system according to the present invention includes first and second cylindrical reflecting surfaces, wherein the first reflecting surface has a center axis of curvature and a second reflecting surface. The angle formed by the center axis of curvature of the reflecting surface in space is substantially perpendicular to the first reflecting surface.
A wide-angle image optical system including an optical system for forming or observing light incident on and reflected by the first reflecting surface, wherein the first reflecting surface is a convex surface and the second reflecting surface is a convex surface. . Another wide-angle imaging optical system according to the present invention includes first and second cylindrical reflecting surfaces, and substantially defines an angle formed in space between a central axis of curvature of the first reflecting surface and a central axis of curvature of the second reflecting surface. A wide-angle image optical system comprising: an optical system disposed at a right angle and configured to form an image or observe light reflected and incident on the second reflecting surface after being incident on and reflected on the first reflecting surface, The first reflecting surface is configured as a convex surface, and the second reflecting surface is configured as a concave surface. Still another wide-angle image optical system according to the present invention includes first and second cylindrical reflecting surfaces, and forms an angle between a center axis of curvature of the first reflecting surface and a center axis of curvature of the second reflecting surface in space. A wide-angle image optical system including an optical system arranged at a substantially right angle and configured to observe or form an image of light incident on the first reflecting surface and reflected and then incident on the second reflecting surface and reflected, The first reflection surface is configured as a concave surface, and the second reflection surface is configured as a convex surface. Still another wide-angle image optical system according to the present invention includes first and second cylindrical reflecting surfaces, and forms an angle between a center axis of curvature of the first reflecting surface and a center axis of curvature of the second reflecting surface in space. A wide-angle image optical system comprising an optical system arranged at a substantially right angle and configured to image or observe light reflected and incident on the second reflection surface after being incident on and reflected on the first reflection surface, The first reflection surface is configured as a concave surface, and the second reflection surface is configured as a concave surface. In each of the wide-angle image optical systems, the first and second cylindrical reflecting surfaces are cylindrical surfaces,
It can be a toric surface, a toroidal surface or a loose conical surface. In the wide-angle image optical system, the optical system that forms the light may be an imaging camera.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a wide-angle image optical system according to the present invention will be described below with reference to the drawings. FIG. 1 is a view showing a first embodiment of a wide-angle image optical system according to the present invention, wherein FIG. 1A is a side view, and FIG. 1B is a plan view of a portion where an imaging optical system is omitted. FIG. 2C is a perspective view of the same. The first reflecting surface 1 is a convex cylindrical surface and keeps the center axis of the cylinder vertical. The second reflecting surface 2 is also a convex cylindrical surface, and the central axis of the cylinder is horizontal. The light reflected by the first reflecting surface 1 is reflected by the second reflecting surface, and is imaged on an image forming surface 4 by a photographic lens which is an image forming optical system 3. With this configuration, a panoramic photograph exceeding 180 ° can be easily obtained.

FIGS. 2A and 2B show a second embodiment of the wide-angle image optical system according to the present invention. FIG. 2A is a side view, and FIG. (C) is a perspective view of the same. The scene of the outside world and the wide-angle image of the scene are schematically illustrated in FIG. The first reflecting surface 21 is a concave cylindrical surface and keeps the center axis of the cylinder vertical. The second reflecting surface 22 is a convex cylindrical surface, the central axis of the cylinder is horizontal, and the angle between the central axes is a right angle. In general, the angle between two straight lines existing in the space is the angle between two straight lines when one or both straight lines are translated and crossed. The light reflected on the first reflecting surface 21 is reflected on the second reflecting surface 22 and is imaged on an image forming surface 24 by a photographic lens forming an image forming optical system 23. With this configuration, a wide-angle panoramic photograph close to 180 ° can be easily obtained.

FIG. 3 is a view showing a third embodiment of the wide-angle image optical system according to the present invention. FIG. 3A is a side view, and FIG. (C) is a perspective view of the same. The first reflecting surface 31 is a convex cylindrical surface and keeps the central axis of the cylinder horizontal. The second reflecting surface 32 is a concave cylindrical surface, and the central axis of the cylinder is vertical. The light reflected by the first reflecting surface 31 is reflected by the second reflecting surface 3
The light is reflected at 2 and is imaged on an image plane 34 by a photographic lens forming an image forming optical system 33. With this configuration, a wide-angle panoramic photograph close to 180 ° can be easily obtained.

FIG. 4 is a view showing a fourth embodiment of the wide-angle image optical system according to the present invention, wherein FIG. 4A is a side view, and FIG. (C) is a perspective view of the same. The first reflecting surface 41 is a concave cylindrical surface and keeps the central axis of the cylinder vertical. The second reflection surface 42 is also a concave cylindrical surface, and the central axis of the cylinder is horizontal. The light reflected on the first reflecting surface 41 is reflected on the second reflecting surface 4
The light is reflected by 2 and is imaged on an imaging surface 44 by a photographic lens forming an imaging optical system 43. With this configuration, a wide-angle panoramic photograph close to 180 ° can be easily obtained.

FIG. 5 is a view showing a fifth embodiment of a wide-angle image optical system according to the present invention. FIG. 5A is a side view, and FIG. (C) is a perspective view of the same. The first reflecting surface 51 is a concave cylindrical surface and keeps the central axis of the cylinder horizontal. The second reflecting surface 52 is also a concave cylindrical surface and the central axis of the cylinder is also horizontal, but they are kept at 90 ° to each other. The light reflected on the first reflecting surface 51 is reflected on the second reflecting surface 52 and is imaged on an image forming surface 54 by a photographic lens forming an image forming optical system 53. With this configuration, a wide-angle panoramic photograph close to 180 ° can be easily obtained.

FIG. 6 is a view showing a sixth embodiment of the wide-angle image optical system according to the present invention, wherein FIG. 6A is a side view, and FIG. (C) is a perspective view of the same. The first reflecting surface 61 is a convex cylindrical surface and keeps the center axis of the cylinder vertical. The second reflecting surface 62 is a concave cylindrical surface, and the central axis of the cylinder is also kept horizontal. The light reflected by the first reflecting surface 61 is reflected by the second reflecting surface 62 and is imaged on an image forming surface 64 by a photographic lens forming an image forming optical system 63. With this configuration, a wide-angle panoramic photograph exceeding 180 ° can be easily obtained.

FIG. 7 is a perspective view showing a seventh embodiment of the wide-angle image optical system according to the present invention. FIG. 8 is a side view of the optical path of the optical system. The first reflecting surface 71 is a convex cylindrical surface, and the center axis of the cylinder is inclined by 20 ° with respect to a vertical line. The second reflecting surface 72 is a convex cylindrical surface and the center axis of the cylinder is also kept horizontal, but the mirror surface is inclined by 25 ° with respect to the horizontal plane. The light reflected by the first reflecting surface 71 is
Are reflected by the reflection surface 72, and are imaged by the CCD camera 7 and displayed on the television monitor 8. The data of the optical system is shown below. Radius of curvature (mm) Interval (mm) First reflective surface 71 (Y-cylindrical convex) 25.0 10.0 Second reflective surface 72 (X-cylindrical convex) 25.0

FIG. 9 is a perspective view showing an eighth embodiment of the wide-angle image optical system according to the present invention. FIG. 10 is a side view of the optical path of the optical system. The first reflecting surface 81 is a concave cylindrical surface, and the center axis of the cylinder is inclined by 80 ° with respect to a horizontal line. The second reflecting surface 82 is a concave cylindrical surface, and the central axis of the cylinder is also kept horizontal, but the axis of the mirror surface is 35 ° with respect to the vertical surface.
° is tilted. The light reflected by the first reflecting surface 81 is reflected by the second reflecting surface 82, is imaged by the CCD camera 7, and is displayed on the television monitor 8. The data of the optical system is shown below. Radius of curvature (mm) Interval (mm) First reflective surface 81 (Y-cylindrical concave) 25.0 30.0 Second reflective surface 82 (X-cylindrical concave) 25.0

FIG. 11 is a side view showing a ninth embodiment in which the first reflecting surface mirror 1 of the first embodiment of the wide-angle image optical system according to the present invention is replaced by a first reflecting surface 91 having a conical surface. FIG. The vertical angle of view below the first embodiment can be made wider.

FIG. 12 shows a ninth embodiment in which the first reflecting surface mirror 1 of the first embodiment of the wide-angle image optical system according to the present invention is replaced by a first reflecting surface 101 made of a toric surface. FIG. There is a feature that a larger vertical vertical angle of view can be obtained than in the first embodiment.

[0018]

[Modifications] Various modifications can be made to the embodiments described above in detail within the scope of the present invention. Depending on the combination of the two reflecting surfaces, the image may be vertically and horizontally inverted, horizontally inverted and vertically inverted, but this can be recovered by using another optical system, for example, a reflecting mirror. Of course, it is also possible to form an image on a film or a CCD via an imaging lens instead of the television camera. By introducing a cylindrical surface with a toric surface or a mirror surface of the above-mentioned conical surface for correcting a distorted image, the cylindrical surface can be corrected to a shape that meets the requirements such as the angle of view and aberration. In the present invention, the meaning of the cylindrical shape should be understood as a concept including a toric surface, a conical surface, and the like inserted for such a correction. An example of taking a panoramic image has been described.
Can be observed by projecting light from the reflective surface of the device onto a screen.

[0019]

As described above, according to the present invention, an ultra-wide-angle lens having a diagonal angle of view of 180 ° is formed by a curved mirror 2
It can be composed of a piece and a simple imaging lens following it. Also,
Chromatic aberration does not occur in the area before the mirror, and each aberration can be corrected only by the subsequent imaging optical system. This reduces the number of design steps and reduces manufacturing constraints, thus reducing weight. It is possible to provide a super-wide-angle lens which is inexpensive and has good performance. Further, in the wide-angle image optical system according to the present invention,
It has an excellent feature that there is no decrease in the amount of peripheral light that cannot be avoided with a conventional wide-angle lens.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams showing a first embodiment of a wide-angle image optical system according to the present invention, wherein FIG. 1A is a side view, and FIG. 1B is a plan view of a portion where an imaging optical system is omitted. FIG. 3C is a schematic diagram showing the relationship between the subject and the image.

FIGS. 2A and 2B are views showing a second embodiment of the wide-angle image optical system according to the present invention, wherein FIG. 2A is a side view, and FIG. 2B is a plan view of a portion from which the imaging optical system is omitted. FIG. 2C is a perspective view of the same.

FIGS. 3A and 3B are views showing a third embodiment of the wide-angle image optical system according to the present invention, wherein FIG. 3A is a side view, and FIG. 3B is a plan view of a portion from which the imaging optical system is omitted. FIG. 2C is a perspective view of the same.

4A and 4B are diagrams showing a fourth embodiment of the wide-angle image optical system according to the present invention, wherein FIG. 4A is a side view, and FIG. 4B is a plan view of a portion from which the imaging optical system is omitted. FIG. 2C is a perspective view of the same.

5A and 5B are diagrams showing a fifth embodiment of the wide-angle image optical system according to the present invention, wherein FIG. 5A is a side view, and FIG. 5B is a plan view of a portion where the imaging optical system is omitted. FIG. 2C is a perspective view of the same.

FIGS. 6A and 6B are views showing a sixth embodiment of the wide-angle image optical system according to the present invention, wherein FIG. 6A is a side view, and FIG. 6B is a plan view of a portion where the imaging optical system is omitted. FIG. 2C is a perspective view of the same.

FIG. 7 is a perspective view showing a seventh embodiment of the wide-angle image optical system according to the present invention.

8 is a side view of an optical path of the optical system shown in FIG.

FIG. 9 is a perspective view showing an eighth embodiment of the wide-angle image optical system according to the present invention.

FIG. 10 is a side view of the optical path of the embodiment shown in FIG.

FIG. 11 is a side view showing a ninth embodiment of a wide-angle image optical system according to the present invention.

FIG. 12 is a side view showing a tenth embodiment of a wide-angle image optical system according to the present invention.

[Explanation of symbols]

1,21,31,41,51,61,71,81,9
1,101 first reflection surface 2,22,32,42,52,62,72,82,9
2,102 second reflection surface 3,23,33,43,53,63,93,103
Imaging optical system 4, 24, 34, 44, 54, 64, 94, 104
Image plane 7 CCD camera 8 Television monitor

Claims (6)

[Claims] 1. A method comprising: first and second cylindrical reflecting surfaces;
The angle formed by the center axis of curvature of the first reflecting surface and the center axis of curvature of the second reflecting surface in a space is substantially perpendicular to the first reflecting surface. A wide-angle image optical system comprising an optical system for forming or observing incident and reflected light, wherein the first reflection surface is a convex surface and the second reflection surface is a convex surface. 2. A method comprising: first and second cylindrical reflecting surfaces;
The angle formed by the center axis of curvature of the first reflecting surface and the center axis of curvature of the second reflecting surface in a space is substantially perpendicular to the first reflecting surface. A wide-angle image optical system including an optical system that forms or observes incident and reflected light, wherein the first reflection surface is a convex surface and the second reflection surface is a concave surface. 3. A method comprising: first and second cylindrical reflecting surfaces;
The angle formed by the center axis of curvature of the first reflecting surface and the center axis of curvature of the second reflecting surface in a space is substantially perpendicular to the first reflecting surface. A wide-angle image optical system including an optical system for forming an image or observing incident and reflected light, wherein the first reflection surface is a concave surface and the second reflection surface is a convex surface. 4. Includes first and second cylindrical reflective surfaces,
The angle formed by the center axis of curvature of the first reflecting surface and the center axis of curvature of the second reflecting surface in a space is substantially perpendicular to the first reflecting surface. A wide-angle image optical system including an optical system for forming or observing incident and reflected light, wherein the first reflection surface is a concave surface and the second reflection surface is a concave surface. 5. The wide-angle image optical system according to claim 1, wherein said first and second cylindrical reflecting surfaces are a cylindrical surface, a toric surface, a toroidal surface, and a loose conical surface. 6. The wide-angle image optical system according to claim 1, wherein the optical system for forming an image of the light is an imaging camera.