JP2000221391A - Image pickup unit using fisheye lens, picture display device and information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a plane picture in which the omission of a picture data is extremely reduced by fetching out the data quantity of a picture near the viewing angle of 90 degrees centering an optical axis much and the interpolation of an omitted part is reduced and also which is made natural in the case of converting into the plane picture after executing photographing at least the viewing angle of 90 degrees by using a fisheye lens. SOLUTION: The picture is picked up by a camera 2 by using the fisheye lens 1 in which the image height(h) of the picture, a focal distance (f) and the viewing angle (θ) at a certain point have the expression of (h)=nf.tan (θ/m) ((m) and (n) satisfy 1.6<=m<=3 and (m)-0.4<=(n)<=(m)+0.4) when the image height is set as (h), and the focal distance is set as (f) and the viewing angle is set as θ, and the picture data outputted from the camera 2 is converted into the plane picture by a picture data processing part 3 and is outputted to a monitor device 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus, an image display apparatus, and an information recording medium using a fish-eye lens which can convert the image picked up using a fish-eye lens into a planar image, and convert the converted image to high quality. About.

[0002]

2. Description of the Related Art Recently, a monitoring system using a camera capable of remotely monitoring a product inspection in a factory or a construction site at a construction site has been developed. Such a monitoring system is required to be able to monitor a wide range with a limited number of cameras, depending on the monitoring content. In order to realize this, recently, a monitoring system using a fish-eye lens capable of photographing at an angle of view of at least 90 degrees in each direction with respect to the optical axis in all viewing directions around the optical axis has been developed. Is underway.

[0003] If such a fisheye lens is used, it is possible to obtain an image of the whole space with one camera. That is, considering the space as a single sphere, a camera was installed at the center of the sphere, a hemispherical image was captured by a fish-eye lens, and then the camera was rotated 180 degrees from that position to take a picture first. By taking a hemispherical image in the direction opposite to the direction and combining the two images, 36
It is possible to capture images in all viewing directions in a space of 0 degrees, that is, to capture a spherical image. And it is also performed to convert it into a planar image.

As a conventional system using such a fish-eye lens, there is, for example, a system disclosed in Japanese Patent Application Laid-Open No. 6-501585 (hereinafter referred to as conventional technology).
This prior art makes it possible to shoot in all directions of view, but the lens used for the image height of the image at a certain point of the subject obtained by the fisheye lens is h and the focal length of the fisheye lens is f and the angle of view are θ, these image height h, focal length f, and angle of view θ are h = f · θ
Is a fisheye lens having the following relationship. This is described in Japanese Patent Application Laid-Open No. 6-501585 as a fisheye lens.
This is clear from the fact that a Nikon 8 mm F2.8 lens is used. Conventionally, a fisheye lens is h = f · θ
The relationship is usually 8mm, F
The 2.8 fisheye lens is also a lens having a relationship of h = f · θ.

[0005]

A method of capturing an image using a fisheye lens having the relationship of h = f · θ and converting it into a planar image is called equidistant projection and has such characteristics. Images taken with a fisheye lens
Peripheral part of image (angle of view 90 with respect to optical axis of fisheye lens)
However, when the image data is converted as a planar image, the missing portion of the image data at the peripheral portion of the image increases, and the missing portion has to be interpolated. In addition, there is a problem that an image photographed by a fish-eye lens having such characteristics has distortion at a peripheral portion of the image.

The present invention relates to a case where a fish-eye lens is used to capture an image at an angle of view of at least 90 degrees with respect to the optical axis in all viewing directions centered on the optical axis, and then convert the image into a planar image. By extracting a large amount of image data near an angle of view of 90 degrees around the optical axis, loss of image data can be suppressed as small as possible, interpolation of the lost portion can be reduced, and a natural plane can be obtained. It is an object of the present invention to provide an image capturing apparatus, an image display apparatus, and an information recording medium using a fisheye lens capable of obtaining an image.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for photographing at all angles of view of at least 90 degrees with respect to the optical axis in all directions around the optical axis of the fisheye lens. An imaging device using a fisheye lens to perform
When the fisheye lens has an image height h at a certain point of the subject obtained by the fisheye lens, the focal length of the fisheye lens f, and the angle of view θ, these image height h, the focal length f, and the angle of view θ are: h = 2f · tan (θ / 2).

According to another aspect of the present invention, there is provided an imaging apparatus using a fish-eye lens which performs photographing in all directions of view centered on the optical axis of the fish-eye lens at an angle of view of at least 90 degrees in each direction with respect to the optical axis. When the fisheye lens has an image height h at a certain point of the subject obtained by the fisheye lens, the focal length of the fisheye lens f, and the angle of view θ, these image heights h, focal length f, and angle of view θ , H = nf · tan
(Θ / m) (where m and n are 1.6 ≦ m ≦ 3, m−
0.4 ≦ n ≦ m + 0.4).

In another invention, in addition to the above-mentioned inventions, the fisheye lens is constituted by a master lens provided in an existing image pickup device and an attachment lens attached to the master lens.

Further, an image display device according to the present invention provides an image data processing section for converting an image obtained by the image pickup device according to claim 1, 2 or 3 into a planar image, and a display for displaying the converted planar image. Part.

In the information recording medium of the present invention, when the image height of an image at a certain point of a subject is h, the focal length of the fisheye lens is f, and the angle of view is θ, these image height h, focal length f, The angle of view θ is h = nf · tan (θ / m) (where m and n are 1.6 ≦ m ≦ 3, m−0.4 ≦ n ≦ m + 0.
4) a step of converting an image obtained by the fisheye lens having the relationship of 4) into a plane image, a step of displaying a predetermined portion of the converted plane image on a display unit, and a step of continuously changing the predetermined portion by an instruction means. Is recorded.

The fish-eye lens used in the present invention has h = n
f · tan (θ / m) (where 1.6 ≦ m ≦ 3, m−
0.4 ≦ n ≦ m + 0.4), and
The fisheye lens having such a relationship has an enlarged image at the peripheral portion (around the angle of view of 90 degrees with respect to the optical axis of the fisheye lens) as compared with a normal fisheye lens in which h = f · θ. In addition, loss of image data in the peripheral portion can be suppressed as much as possible. This makes it possible to reduce interpolation of image data when converting a captured image into a planar image, and to obtain a more natural planar image.

According to the present invention, when a fisheye lens is formed by attaching an attachment lens to a master lens provided in an existing camera, the fisheye lens can be attached to almost all existing cameras. Can be inexpensive because only a new one needs to be manufactured.

Furthermore, an image display device that displays a planar image converted from an image captured by the above-described imaging device having a fish-eye lens on a display unit makes the displayed image easy to see, increasing the value of the device. When the computer reads the information recording medium on which the above-described steps are recorded and executes the program, a more natural two-dimensional image is displayed on the display unit, and the display part can be freely set within the range of the captured image. Can be moved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 schematically shows an image processing system constructed using an image pickup apparatus using a fisheye lens according to the present invention. This image processing system includes a fisheye lens 1
Camera (video camera, etc.) that becomes an imaging device equipped with
2, an image data processing unit 3 for processing image data from the camera 2, and a monitor device 4 for displaying an image processed by the image data processing unit 3. The image data processing unit 3 includes a so-called CPU and a memory unit 2 and performs various processes using image data output from the camera 2. An operation of converting the image captured by the above into a planar image is also performed.

A fisheye lens 1 used in this embodiment
As shown in FIG. 2, a lens unit (referred to as a master lens unit) 10 provided in the camera 2 can be roughly divided.
And a lens unit (referred to as an attachment lens unit) 20 that is detachably attachable to the master lens unit 10. By attaching the attachment lens unit 20 to the master lens unit 10, the function as the fisheye lens 1 of the present invention is achieved. I do.

The attachment lens section 20 includes a first lens 21, a second lens 22, a third lens 23, a fourth lens 24, and a flat plate 25. The master lens unit 10 is interposed between the fifth lens 11, the sixth lens 12, the seventh lens 13, the eighth lens 14, the ninth lens 15, and the sixth lens 12 and the seventh lens 13. The stop 26 is formed.

Here, the curvature R (= the diameter of the curved surface of the lens) and the interval D (= the lens thickness or the lens interval) of each lens in this embodiment are as follows. That is, in order from the curvature R1 of the left curved surface of the leftmost first lens 21 in FIG.
R2 is 40.0 mm and 9.0 mm, and curvatures R3 and R4 of the second lens 22 are −26.0 mm and 80.0 mm. The curvatures R5 and R6 of the third lens 23 are −3.
At 6.0 mm and -20.0 mm, the curvatures R7 and R8 of the fourth lens 24 are -81.0 mm and -27.0 mm.

Furthermore, the curvatures R9 and R1 of the fifth lens 11
0 is 14.0 mm and 68.0 mm, and the sixth lens 12
Are 9.0 mm and 3.0 mm, respectively. Further, the curvatures R13, R14 of the seventh lens 13
Are 0.0 mm and -8.0 mm, and the curvatures R15 and R16 of the eighth lens 14 are 10.0 mm and -6.0 mm,
The curvatures R17 and R18 of the ninth lens 15 are 11.0 mm
And -9.0 mm.

On the other hand, the thickness D1 of the leftmost first lens 21 in FIG. 2 is 1.2 mm, the distance D2 between the first lens R21 and the second lens 22 is 10.0 mm, and the second lens 22
Has a thickness D3 of 1.2 mm. The distance D4 between the second lens 22 and the third lens 23 is 14.0 m.
m, the thickness D5 of the third lens 23 is 2.0 mm, and the distance D6 between the third lens 23 and the fourth lens 24 is 3.0 m.
m, the thickness D7 of the fourth lens 24 is 5.0 mm.

Further, the fourth lens 24 and the fifth lens 11
Is 8 mm, the thickness D9 of the fifth lens 11 is 2.0 mm, and the fifth lens 11 and the sixth lens 1
The distance D10 from the second lens D2 is 0.3 mm, and the thickness D11 of the sixth lens 12 is 0.8 mm. Seventh lens 1
The third, eighth, and ninth lenses 14 and 15 are movable in the optical axis direction in order to change the magnification, and the intervals between the subsequent lenses indicate the maximum intervals. The distance D12 between the diaphragm 26 and the seventh lens 13 is 4.0 mm, the thickness D13 of the seventh lens 13 is 1.0 mm, and the seventh lens 13
The distance D14 between the lens and the eighth lens 14 is 1.0 mm,
The thickness D15 of the lens 14 is 4.0 mm.

The distance D between the eighth lens 14 and the ninth lens 15
16 is 2.0 mm, and the thickness D17 of the ninth lens 15 is
Is 4.0 mm. Parallel plane plates 16 and 17 are disposed on the right side of the ninth lens 15 in FIG.

In such a configuration, the first lens 21
Is passed through the first to fourth lenses 21 to 24, further passes through the fifth to ninth lenses 11 to 15, and is input to the CCD image pickup device 30 in the camera 2. Further, the attachment lens unit 20 includes a first lens 21.
The respective parallel lights that have entered are also output from the fourth lens 24 as parallel lights. Therefore, the attachment lens unit 20 can be attached to most cameras. However, the width (represented by w in the figure) of each parallel light beam output from the fourth lens 24 of the attachment lens unit 20 is 1/1 / the effective diameter of the master lens 10 of the camera to be mounted. 2. In FIG. 2, a spherical surface 40 in front of the first lens 21 represents a virtual imaging target surface.

As described above, the desired fisheye lens 1 is formed by the master lens unit 10 and the attachment lens unit 20.
Is configured. As described above, in the present invention, when the fisheye lens 1 has an image height h at a certain position of a subject, the focal length of the fisheye lens f, and the angle of view θ, these image height h, focal length f, the angle of view θ is h = nf ·
tan (θ / m) (1.6 ≦ m ≦ 3, m−0.4 ≦ n ≦
m + 0.4), and particularly h = 2f. tan (θ
/ 2) is preferable.

As mentioned above, the fisheye lens generally used in the past has a relation of h = f · θ,
These functions are used to map a spherical image as a polar-transformed image.
= 2f · sin (θ / 2), h = 2f · sinθ, h =
f · tan θ is also conceivable.

FIG. 3 shows a fisheye lens with h = 2f · tan (θ / 2) h = f · θ h = 2f · sin (θ / 2) h = f · sin θ h = f · tan θ h = 3f · tan (Θ / 3) h = 2f · tan (θ / 1.6) Each angle of view θ in the case of a fisheye lens having the relationship:
FIG. 6 is a diagram showing a relationship between the image height and the image height h. Here, θ = 9
0 degree indicates an angle of view based on the optical axis (an angle of view on the optical axis is 0 degree).

In FIG. 3, a curve C1 is obtained by h = 2f · t.
The relationship between the angle of view θ and the image height h in the fisheye lens 1 of the above embodiment having the relationship of an (θ / 2) is shown, and the curve C2 is the image in the fisheye lens having the relationship of h = f · θ. This shows the relationship between the angle θ and the image height h. A curve C3 shows the relationship between the angle of view θ and the image height h in a fisheye lens having the relationship h = 2f · sin (θ / 2), and the curve C4 has a relationship h = f · sin θ. 9 shows the relationship between the angle of view θ and the image height h of a fisheye lens. A curve C5 shows the relationship between the angle of view θ and the image height h in a fisheye lens having the relationship h = f · tan θ.

The curve C1 'is given by h = 3f.tan
(Θ / 3), and the curve C1 ″ is
The graph shows a relationship having a relationship of h = 2f · tan (θ / 1.6). These curves C1 ′ and C1 ″ are obtained by the equation h = nf · tan (θ / m) (where 1.6 ≦ m ≦
3, m−0.4 ≦ n ≦ m + 0.4).

As can be seen from FIG. 3, the angle of view θ is 9
The degree of increase of the image height h at a portion close to 0 degrees is h = f ·
The fisheye lens having the relationship of tan θ is the largest, and h =
2f · tan (θ / 1.6) is the second largest,
The fisheye lens 1 having a relationship of h = 2f · tan (θ / 2) is the third largest. Further, in the fisheye lens having the relationship of h = f · θ, the change of the image height h changes linearly with the change of the angle of view θ, and further, h = 2f · sin (θ /
2), a fisheye lens having a relationship of h = f · sin θ
It can be seen that the degree of increase in the image height h tends to decrease as the angle of view approaches 90 degrees.

However, in the fisheye lens having the relationship of h = f · tan θ, the degree of increase in the image height becomes larger as it approaches the peripheral portion (angle of view 90 °), and a larger amount of image data is obtained. But tan at θ = 90 degrees
θ becomes infinite. Since a fisheye lens needs to obtain an image in all the viewing directions around the optical axis in at least 90 degrees with respect to the optical axis, h = f · tan θ is not suitable for a fisheye lens. It can be said that.

Therefore, as a fisheye lens, h = 2f ·
tan (θ / 1.6), h = 2f · tan (θ / 2),
h = f · θ, h = 2f · sin (θ / 2), h = f · s
The fisheye lens has a relationship of inθ. FIG. 4 shows a fisheye lens (h = 2f · tan) of this embodiment.
(Θ / 2)) and the image height h when the angle of view θ is changed in units of 10 degrees with respect to the optical axis of the other fish-eye lens as concentric circles centered on the optical axis of each fish-eye lens. (A) is the fisheye lens 1 of the present embodiment having a relationship of h = 2f · tan (θ / 2), and (B) is h = f
A fisheye lens having a relationship of θ, (C): h = 2f · s
a fisheye lens having a relationship of in (θ / 2), (D) is h
= F · sin θ for the respective fisheye lenses. In FIG. 4, ho is the image height of the image Mo near the optical axis of each fisheye lens,
he is the image height of the image Me near the angle of view of 90 degrees.

As can be seen from FIG. 4, h = 2f ·
A fisheye lens having a relationship of sin (θ / 2) or h = f ·
With a fisheye lens having a relationship of sin θ, the image height near the angle of view of 90 degrees is smaller than the image height near the optical axis, and only a small amount of image data can be obtained. Further, even in the conventional fisheye lens of h = f · θ, the image height he of the image Me in the peripheral portion of the fisheye lens is the same as the image height ho of the image Mo near the optical axis. Become.

From these facts, from the viewpoint of how much data amount is obtained at or near the angle of view of 90 degrees, h = 2f · sin (θ / 2) and h = f · sin
It can be said that a fisheye lens having a relationship of θ is not preferable, and a fisheye lens of h = f · θ generally used conventionally is not sufficient.

On the other hand, h = 2f ·
In the fisheye lens 1 having a relationship of tan (θ / 2), the image height he of the image Me in the peripheral portion of the fisheye lens 1 is enlarged with respect to the image height ho of the image Mo near the optical axis, and is compared with the conventional one. Thus, more image data can be obtained, and no distortion occurs in the image.

FIG. 5 shows an example expressed by another relational expression of the image height h and the angle of view θ. FIG. 5 shows the curve C2 shown in FIG.
(This corresponds to h = f · θ) and curve C1 ″ (this is 2
f · tan (corresponding to θ / 1.6)) is also shown. FIG. 5 shows a curve C10,
C11, C12 and C13 are shown. Curve C10
Is obtained by converting h = 1.6f · tan (θ / 2) to a curve C11.
Is obtained by converting h = 1.2f · tan (θ / 1.6) to the curve C1.
2 is obtained by converting h = 3.4f · tan (θ / 3) into a curve C13.
Indicates h = 2.4f · tan (θ / 2).

By the way, one spherical image obtained by combining two semi-curved images taken at an angle of view of 90 degrees with respect to the optical axis in the entire field of view centering on the optical axis of the fisheye lens 1 is When the image data is converted into a planar image by the image data processing unit 3, it is necessary to interpolate the missing image data in the peripheral part of the image (around the angle of view of 90 degrees with respect to the optical axis). The image of the peripheral portion is an enlarged image, and a large amount of data in the peripheral portion can be extracted. Therefore, the amount of image data to be interpolated can be significantly reduced as compared with the conventional method.

Further, a method of taking an image at an angle of view of at least 90 degrees with respect to the optical axis in the entire field of view centered on the optical axis and then converting the image into a polar coordinate transformed image is as follows. Do it like this.

First, X, as shown in FIG.
Consider a Y, Z coordinate system. At this time, the optical axis of the fisheye lens 1 is defined as the Z axis. Then, the coordinates of a certain point p are represented by (X1, Y
1, Z1), and XZ which looks up this point p from the origin O of the coordinates
The angle with respect to the plane is θ. Further, an angle with respect to the XZ plane that goes up to the point p from the position of Z1 on the Z axis is φ.

Next, as shown in FIG. 7, an xy coordinate system having an optical axis (Z axis) as an origin o on the surface of the CCD image pickup device 30 is considered. The imaging point (p ′) is located as shown in FIG. In FIG. 7, the reason why φ is + π is that the image formed at the point p ′ is inverted up, down, left, and right with respect to the image of the object plane (point p). In addition, the optical axis in FIG. 7 exists from the origin o of the xy coordinates in a direction orthogonal to the paper surface.

Here, the position of the point p 'is defined by the origin o and the point p'.
The length (h) and the angle φ + π between op ′ and the x-axis
As polar coordinates. When the polar coordinates are represented on the xy rectangular coordinates, the position (x
1, y1) is represented by x1 = h · cos (φ + π) (1) y1 = h · sin (φ + π) (2), and the image height h of the point p ′ is h = 2f · tan (θ /
2), this h = 2f · tan (θ / 2)
Is substituted into the expressions (1) and (2), the coordinates (x1, y1) of the imaging point p ′ on the surface of the CCD image pickup device 30 are given by: x1 = 2f · tan (θ / 2) · cos (φ + π) (3) y1 = 2f · tan (θ / 2) · sin (φ + π) (4) After all, x1 = −2f · tan (θ / 2) · cosφ (5) y1 = −2f · tan (θ / 2) · sin φ (6) Where θ and φ in the above equation are

(Equation 1) It is.

As described above, the position p 'on the surface of the CCD 30 relative to the point p on the object plane can be obtained.

Next, steps for photographing a spherical surface (= all directions) with the camera 2 using the fisheye lens 1 and displaying the image on the monitor device 4 as a display unit will be described with reference to FIG.

First, a hemisphere in one direction is photographed by the camera 2 with the fisheye lens 1 (step S1). This gives C
A hemispherical image is captured on the surface of the CD imaging device 30 as an image obtained by performing polar coordinate conversion. Next, the camera 2 is rotated 180 degrees to photograph a hemisphere in the opposite direction (step S).
2). As a result, the remaining hemispherical image is photographed as a polar coordinate transformed image on the surface of the CCD imaging device 30.

Next, the two images are combined by the image data processing unit 3 to form a two-dimensional image (step S).
3). At this time, it is necessary to correct a region corresponding to a hemispherical joint portion. However, the polar coordinate transformed image obtained by the fisheye lens 1 has a large amount of information in the peripheral portion, and the joining process is easy. Thereafter, a predetermined portion of the plane image obtained by the plane processing is cut out and displayed on the monitor device 4 (step S4).

When the user wants to change the displayed predetermined portion, the user moves the screen by an instruction means such as a mouse. This movement can be continuously varied in any direction of 360 degrees around the portion displayed on the monitor device 4 (step S5).

In the above steps, the case where a spherical surface in all directions of 360 degrees is photographed has been described, but the same steps are performed when only one hemispherical surface is photographed. However, step S2 becomes unnecessary, and the joining processing of the two images in step S3 becomes unnecessary.

In this embodiment, the information amount of the peripheral portion of the image obtained by the fisheye lens 1 or another fisheye lens of the present invention is increased, that is, the image of the peripheral portion is enlarged. Will be more convenient. For example, when the inner surface 52 of the cylindrical object 51 is photographed with the optical axis of the fisheye lens 1 according to the present invention aligned with the central axis of the cylindrical object 51 as shown in FIG. Since the peripheral portion can be extracted as an image having a larger amount of information than the central portion, it is possible to easily find a scratch or the like occurring on the inner side surface 52 thereof. Therefore, it can be used for inspection of an object on a pipe such as a water pipe or a gas pipe, and can also be used for monitoring a crack generated on a wall surface such as a tunnel.

Also, the present invention can be used for inspecting the connection status of small components such as ICs. That is, as shown in FIG. 10, when the component 61 is fixed to the board 24 by the solder 63 on the side surfaces 62, 62, conventionally, the soldering state has to be confirmed from the side. However, when there is another component 65 on the side, the portion of the solder 63 on the component 65 side cannot be visually recognized by the camera,
It has become difficult to automate inspections. However, in the camera 2 using the fisheye lens 1 of the present invention, as shown in FIG. 10A, even when the fisheye lens 1 is arranged right above the component 61, the side of the component 61 can be sufficiently imaged, and 2 enables an automatic inspection.

Each of the above embodiments is an example of a preferred embodiment of the present invention. However, the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention. It is. For example, the master lens unit 10
A fish-eye lens may be constituted only by the attachment lens unit 20 excluding the above, or a fish-eye lens in which the master lens unit 10 and the attachment lens unit 20 are integrally inseparable. In addition, the fisheye lens 1 shown in the above embodiment
The lens configuration and the numerical value of each lens are one embodiment, and other configurations and numerical values may be adopted.

Further, the fisheye lens 1 according to the above-described embodiment is used.
And as a system using other fisheye lens of the present invention,
An image processing system 71 shown in FIG. 11 may be employed.
The image processing system 71 includes a camera 2 having a fisheye lens 1 or another fisheye lens of the present invention,
And an image data processing unit / monitor 5 connected by a cable. The image data processing unit and monitor 5
It is a so-called personal computer with a monitor, to which a keyboard 5a and a mouse 5b as instruction means are connected.

The image data processing unit and monitor 5
Has a hard disk (not shown) in which the contents of an information recording medium (floppy disk) 6 in which a program for performing steps S3, S4, and S5 shown in FIG. When this program is installed, the same functions as those of the image data processing unit 3 described above are performed.

The transfer of the image data from the camera 2 to the image data processing unit / monitor 5 may be performed by a memory card such as a flash card other than the cable, or may be performed by wireless such as infrared communication. Further, instead of installing the program using the floppy disk 6, the program may be executed on another recording medium such as a CD-ROM, or the program may be transferred from another storage unit via a network. When the program is transferred via the network, the storage unit of the transmission source or the hard disk (storage unit) in the image data processing unit and monitor 5 is the information recording medium of the present invention.

[0054]

As described above, claims 1 and 2
In the imaging apparatus using the fisheye lens described above, when the image height is h, the focal length is f, and the angle of view is θ, h = nf
Tan (θ / m) (where m and n are 1.6 ≦ m ≦
3, m−0.4 ≦ n ≦ m + 0.4). This is because, in comparison with a normal fisheye lens in which the relationship between the image height h, the focal length f, and the angle of view θ is h = f · θ, the peripheral portion (around the angle of view of 90 degrees with respect to the optical axis of the fisheye lens). Image will be enlarged and the amount of information will increase,
Missing image data in the peripheral area can be suppressed as much as possible. This makes it possible to reduce interpolation of image data when converting a captured image into a planar image,
A more natural planar image can be obtained.

According to a third aspect of the present invention, a fisheye lens is provided by attaching an attachment lens different from the master lens to a master lens provided in an existing image pickup apparatus (camera). So that
It can be attached to most existing imaging devices (cameras), and can be made inexpensive because only the attachment lens needs to be newly manufactured.

Further, the image display device according to claim 4 is
Conversion from a spherical image to a planar image is easy, and a more natural planar image can be displayed. In addition, in the information recording medium according to the fifth aspect, when a computer reads and executes a program in the information recording medium, a more natural planar image can be generated.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image processing system configured using an imaging device using a fisheye lens of the present invention.

FIG. 2 is a diagram schematically showing the configuration of the fisheye lens shown in FIG. 1 and the corresponding width between lenses (lens spacing and lens thickness).

FIG. 3 h = f · θ, h = 2f · sin (θ / 2), h
= F · sin θ, h = f · tan θ, and h = 2f · tan (θ / 2), h
= 3f · tan (θ / 3), h = 2f · tan (θ /
1.6) The fisheye lens of the present invention having the relationship of
It is a figure which shows the relationship between the angle of view (theta) and the image height h, respectively.

4 is an image height when the angle of view is changed in units of 10 degrees with reference to the optical axis of each of the fisheye lenses shown in FIG. 3 (the fisheye lens of the present invention has only h = 2f · tan (θ / 2)). Are represented by concentric circles centered on the optical axis of each fisheye lens.

FIG. 5 shows a fisheye lens having a relationship of h = f · θ and h = f · θ.
2f · tan (θ / 1.6), h = 1.6f · tan
(Θ / 2), h = 1.2f · tan (θ / 1.6), h
= 3.4f · tan (θ / 3), h = 2.4f · tan
Each fisheye lens of the present invention having a relationship of (θ / 2) (FIG. 3
(A part of the fisheye lens shown in FIG. 2 is also shown.) Is a diagram showing the relationship between the angle of view θ and the image height h.

FIG. 6 is a diagram illustrating a method of performing polar coordinate conversion on a hemispherical image obtained by a fisheye lens.

FIG. 7 is a diagram illustrating a method for obtaining the position of an image forming point on the CCD image sensor surface in the polar coordinate conversion of FIG. 6;

8 is a flowchart illustrating steps of image processing performed using the image processing system shown in FIG.

9A and 9B are diagrams showing another example using the imaging device of the present invention, wherein FIG. 9A is a schematic diagram viewed from the side, and FIG.
FIG. 5 is a view seen from the direction of arrow B in FIG.

FIGS. 10A and 10B are diagrams showing still another example using the imaging apparatus of the present invention, wherein FIG. 10A is a schematic diagram viewed from the side, and FIG.
It is the figure seen from the arrow B direction of (A).

FIG. 11 is a diagram illustrating another example of an image processing system configured using an imaging device using a fisheye lens of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 fisheye lens 2 camera (imaging device) 3 image data processing unit (part of image display device) 4 monitor device (part of image display device, display unit) 10 master lens unit 20 attachment lens unit 30 CCD imaging device

[Procedure amendment]

[Submission date] May 2, 2000 (2005.2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claim 2

[Correction method] Change

[Correction contents]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

[0007]

Means for Solving the Problems In order to achieve the above object, the present invention provides imaging in all viewing directions centered on the optical axis of a fisheye lens at an angle of view of at least 90 degrees in each direction with respect to the optical axis. There line, then using the captured data
An imaging apparatus using a fish-eye lens used to convert the image into a planar image , wherein the fish-eye lens sets the image height of an image at a certain point of the subject obtained by the fish-eye lens to h,
When the focal length of the fisheye lens is f and the angle of view is θ,
When the image height h, the focal length f, and the angle of view θ are h = 2f · ta
n (θ / 2).

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

Further, in another invention, in the entire field of view direction around the optical axis of the fisheye lens, we have lines at least taken in angle in each direction 90 degrees to the optical axis as a reference, then the shooting
Is used to convert the data
That a fisheye lens and an imaging apparatus using the fisheye lens is the image height of an image at a point of the object obtained by the fisheye lens h, and the focal length of the fisheye lens f,
Assuming that the angle of view is θ, these image height h, focal length f, and angle of view θ are h = nf · tan (θ / m) (where m and n are
1.6 ≦ m ≦ 3, m−0.4 ≦ n ≦ m + 0.4).

Claims (5)

[Claims] 1. An image pickup apparatus using a fish-eye lens that performs photographing at an angle of view of at least 90 degrees in each direction with respect to the optical axis in all viewing directions centered on the optical axis of the fish-eye lens. When the image height of an image at a certain point of the subject obtained by the fisheye lens is h, the focal length of the fisheye lens is f, and the angle of view is θ, these image height h, focal length f, and angle of view θ are h = 2f · tan (θ /
An imaging device using a fisheye lens, which has the relationship of 2). 2. An imaging apparatus using a fish-eye lens that performs photographing at an angle of view of at least 90 degrees in each direction with respect to the optical axis in all viewing directions around the optical axis of the fish-eye lens. When the image height of an image at a certain point of the subject obtained by the fisheye lens is h, the focal length of the fisheye lens is f, and the angle of view is θ, these image height h, focal length f, and angle of view θ are h = nf · tan (θ /
m) (where m and n are 1.6 ≦ m ≦ 3, m−0.4 ≦
An imaging device using a fish-eye lens, which has a relationship of n ≦ m + 0.4). 3. The fish-eye lens according to claim 1, wherein the fish-eye lens comprises a master lens provided in an existing image pickup device and an attachment lens attached to the master lens. Imaging device. 4. An image data processing unit for converting an image obtained by the imaging apparatus according to claim 1, 2, or 3 into a planar image, and a display unit for displaying the converted planar image. Image display device. 5. The image height of an image at a certain point of a subject is represented by h,
When the focal length of the fisheye lens is f and the angle of view is θ,
When the image height h, the focal length f, and the angle of view θ are: h = nf · ta
n (θ / m) (where m and n are 1.6 ≦ m ≦ 3, m−
(0.4 ≦ n ≦ m + 0.4) a step of converting an image obtained by a fisheye lens having a relationship of: a plane image, a step of displaying a predetermined part of the converted plane image on a display unit, and an instruction of the predetermined part An information recording medium on which a program having at least a step of continuously changing by means is recorded.