JP2002221752A - Moving picture camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide moving picture camera which has a lower cost than an apparatus using a lens and allow picking up an image with little distortion. SOLUTION: A reflecting mirror 2 for making an image in an observed area of an object space be picked up in a desired area of a viewing field of a TV camera is disposed between the TV camera 1 and the object space. A reflecting surface of the reflecting mirror 2 is formed so as to make the image picked up by the TV camera 1 through the reflecting mirror 2 be an orthogonal projection image or a perspective projection image in the observed area of the object space. The TV camera 1 can pick up the image having little distortion without an image processing by a computer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photographing device.

[0002]

2. Description of the Related Art Conventionally, a wide field of view is used for a camera for photographing an intruder for security purposes, a camera for photographing an object to be inspected on a production line of a factory, and a camera for photographing an obstacle near the ground behind in a car. Cameras are required. A wide-angle lens is generally used to obtain a camera with a wide field of view, but it is known that a distorted image as shown in FIG. 7 is obtained when a wide-angle lens with a wide field of view is used. FIG. 7 shows a state in which a lattice pattern in which one lattice is a square is photographed, and it can be seen that a distorted image closer to a circular shape is obtained in a peripheral portion. When such a wide-angle lens is used, the size in the image relative to the actual size in the object space is significantly smaller in the peripheral portion than in the vicinity of the center of the image, and the peripheral portion of the image is substantially smaller than the central portion. The resolution is low.

[0003]

Although some image distortions have been eliminated by using an aspherical lens as a wide-angle lens, the distortion of the image can be completely eliminated by using an aspherical lens. Is difficult and
Further, an aspheric lens that reduces image distortion is expensive and is not suitable for consumer use such as a security camera or a camera mounted on an automobile.

When a TV camera is used as a camera, it has been considered to correct image distortion caused by using a wide-angle lens by performing computer image processing on an original image output from the TV camera. , T
If the image output from the V camera is continuously subjected to computer image processing to remove image distortion, a microcomputer having a high processing capability is required, resulting in an increase in cost. Even if the image distortion is removed by computer image processing, the peripheral part of the captured image has a smaller resolution than the central part. As compared with the central portion, the amount of information obtained is small, and even if the image distortion is removed by computer image processing, the image is greatly deteriorated in the peripheral portion.

The present invention has been made in view of the above circumstances, and an object of the present invention is to dispose a reflecting mirror between a camera and an object space, thereby distorting a wide field of view at a lower cost than a wide-angle lens. It is an object of the present invention to provide a photographing apparatus capable of photographing an image which cannot be obtained conventionally without performing computer image processing, such as obtaining an image having a small number of images, without relying on computer image processing.

[0006]

According to the first aspect of the present invention, a reflector having a reflecting surface which enables an image of a region of interest in an object space to be photographed in a desired region within a field of view of a camera is provided. The reflecting surface of the reflecting mirror is formed so that the dimensional ratio along the plane of interest in the object space matches the dimensional ratio in at least one direction of the image captured by the camera. According to this configuration, the shape of the reflecting surface of the reflecting mirror is set such that the dimensional ratio in at least one direction of the captured image matches the dimensional ratio along the surface of interest in the object space. It is possible to capture an image that is easy to visually recognize by reducing distortion of the image. That is, it is possible to recognize an almost accurate shape and size of an entity in an object space without performing computer image processing such as correcting image distortion on an image captured by a camera. As a result, when a TV camera is used as a camera, the load required for image correction by computer image processing is small, and even if an inexpensive microcomputer with low processing capability is used, a smooth moving image can be obtained with an image with little distortion. Become. In addition, when a camera is used for photographing a photographic photosensitive material, a wide-field image without distortion that could not be photographed even with a wide-angle lens can be photographed. It is possible to obtain a photograph suitable for the purpose of obtaining an indication of the distance and the size of the object.

According to a second aspect of the present invention, in the first aspect of the present invention, the reflecting surface of the reflecting mirror is adjusted so that an image photographed by the camera is an orthographically projected image of a surface of interest in an object space. It has been formed. According to this configuration, since an image obtained by orthographically projecting the plane of interest in the image is obtained, the distance between the objects in the object space and the distance between the objects in the image have a proportional relationship, and the It is possible to accurately reflect the distance of an object and the size of an object on an image.

According to a third aspect of the present invention, in the first aspect of the present invention, the reflecting surface of the reflecting mirror is formed such that an image photographed by the camera is an image obtained by perspectively projecting a plane of interest in an object space. Is what is being done. According to this configuration, since an image obtained by perspectively projecting the surface of interest in the image is obtained, the image is given perspective. That is, if the camera is mounted near the ground and mounted near the ground, the perspective is given so that the top of the image can be seen in the distance,
By setting the field of view such that the road surface near the car is photographed at the lower part and the upper part of the image is photographed on the road surface far from the car, it is possible to obtain an image with perspective corresponding to the human visual characteristics. Will be possible.

According to a fourth aspect of the present invention, in the first to third aspects of the present invention, a specific direction of a plane of interest in an object space is preserved in an image taken by the camera. One cross section of the reflecting surface of the reflecting mirror is formed in a concave shape. According to this configuration, the orientation of the surface of interest in the object space and the orientation of the surface in the image can be matched with respect to the specific direction. That is, when the camera shoots the target area of the object space through the reflecting mirror, the left and right directions are generally reversed, but by using the reflecting mirror designed so that the cross section including the left and right directions is concave, the left and right directions are in the object space. Can be saved in the image.

According to a fifth aspect of the present invention, in the first to fourth aspects, the reflection surface is provided with a marker which is reflected in an image taken by the camera and indicates a reference position of the image. . According to this configuration, it is possible to easily confirm whether or not the direction of the camera is suitable for photographing the target area in the object space. For example,
If the photographing device is mounted on a car, the car can be easily guided to an appropriate position by driving the vehicle so that characters and lines written on the road surface match the markers in the parking lot.

[0011]

(Embodiment 1) FIG. 1 shows a schematic configuration of the present embodiment. FIG. 1 shows an example in which the vicinity of the ground E is set as a target area in the object space, and the TV camera 1 as a camera captures the target area. CCD for TV camera 1
, And a light receiving lens 1b for forming an image of the object space on the light receiving surface of the image sensor 1a.
A reflecting mirror 2 is arranged in front of the TV camera 1, and the TV camera 1 captures an image reflected by the reflecting mirror 2. That is, the reflecting mirror 2 maps the target area in the object space to a desired area in the field of view of the TV camera 1. The reflecting surface of the reflecting mirror 2 is designed to widen the field of view of the TV camera 1. That is,
As shown in FIG. 1, the field of view (represented by an angle θ) of the TV camera 1 is reflected by a reflecting mirror 2 so that the TV camera 1
, The range (represented by the angle φ) becomes wider (φ> θ). Such a relationship is generally the same as that obtained by using a convex mirror as the reflecting mirror 2.

Further, the TV camera 1 is not included in the object space photographed by the TV camera 1 through the reflecting mirror 2.
The positional relationship between the TV camera 1 and the reflecting mirror 2 is set, and the angle between the light beam passing through the optical axis of the TV camera 1 and reflected by the reflecting surface of the reflecting mirror 2 and the optical axis of the TV camera 1 is a right angle. The reflection surface of the reflection mirror 2 is formed so that the reflection angle is also reduced (to be an acute angle). As a result, compared to the case where the TV camera 1 is not reflected in the image captured by the TV camera 1, and the light axis reflected by the reflection surface is orthogonal to the optical axis of the TV camera 1, Occupies a small volume. In other words, when the camera is installed on the wall of a building as a security camera, the size of the projection from the wall can be made relatively small, and when monitoring an obstacle on the road or ground behind the car, The device can be mounted without taking up much of the internal space of the device.

The reflecting surface of the reflecting mirror 2 is a smooth curved surface, and as shown in FIG. 2, is formed in a convex shape as a whole. Such a reflecting surface is used to reflect an image taken by the TV camera 1 in accordance with the position of the reflecting surface of the TV camera 1 and the reflecting mirror 2 such that a surface of interest in the object space is an image without distortion. It is designed by numerical calculation for each small section of the surface.

The orientation of each minute section is set so that the field of view of the TV camera 1 is widened and no distortion occurs in the image while widening the field of view. That is, the range of the region of interest in the object space to be photographed by the TV camera 1,
Each minute section is arranged according to the specifications of the V camera 1 and the relative positional relationship between the TV camera 1 and the reflecting mirror 2. In the present embodiment, the similarity ratio between the object space and the object space in the horizontal and vertical directions is constant and equal so that the image captured by the TV camera 1 is an orthographic image of the region of interest in the object space. The similarity ratio with the object space only in the horizontal direction of the image is set so that the image captured by the TV camera 1 becomes an image of the perspective projection of the region of interest in the object space when the small section is designed as described above. And a case where a micro section is designed. As the perspective projection image in the latter, both one-point perspective and two-point perspective are possible,
For example, if the image is designed so as to obtain a one-point perspective image in which the similarity ratio becomes smaller at a fixed rate as the image becomes higher, it is possible to generate perspective in the image. Here, that the similarity ratio to the object space in the horizontal direction or the vertical direction is constant means that the dimension ratio in the object space in the horizontal direction or the vertical direction is the same in the image.

When the reflecting surface is designed so that the similarity ratio between the object space in the horizontal direction and the vertical direction of the image is constant and equal, a grid pattern in which one grid is a square is photographed. Then, as shown in FIG. 3, it is possible to obtain an image of a lattice pattern in which one lattice is a square. That is, the entity in the object space is photographed so as to have a similar shape in the image, and an image in the form of orthographic projection of the entity in the object space is obtained. In this image, the ratio of the distance between the objects in the object space is stored in the image, so that the distance between the objects and the size of the object can be measured by the image. Such an image is suitable as an image for inspection. Further, in the image picked up by using the reflecting mirror 2, the resolution with respect to the object space is constant at any part, and the image quality is substantially uniform in the entire region in the image while obtaining an image without distortion.

On the other hand, if the reflection surface is designed so that the similarity ratio with the object space in the horizontal direction of the image is constant and the similarity ratio in the horizontal direction is smaller at a higher ratio in the upper part of the image, the same grating is used. When a pattern is photographed, an image is obtained in which the width of the lattice becomes smaller as it goes upward, as shown in FIG. That is, an image in the form of perspective projection of an entity in the object space is obtained. In this image, the perspective is obtained such that the lower part is located in the front and the upper part is located in the distant place, so when mounting on a car and taking an image of the road surface, the distant place is photographed in the upper part of the image With this setting, an easy-to-understand image that matches the visual characteristics of a person can be provided.

In the present embodiment, the positional relationship is set such that the TV camera 1 is not reflected in the image of the TV camera 1, but the positional relationship in which the TV camera 1 is reflected is adopted as necessary. May be. In the above example, the surface of interest in the object space is considered to be a plane. However, when the surface of interest is a curved surface, the shape obtained by developing the surface of interest into a plane (that is, the shape along the curved surface) is orthogonal. It is possible to design the shape of the reflecting surface of the reflecting mirror 2 so as to perform projection or perspective projection. In other words, in the above example, the plane of interest in the object space is assumed to be a plane, and the similarity ratio between the plane of interest in the object space and the image in the image has been described. However, it is generalized to the case where the plane of interest is a curved surface. In other words, the dimensional ratio along the plane of interest in the object space is TV
The reflecting surface of the reflecting mirror 2 is designed to match the dimensional ratio of the image taken by the camera 1 in at least one direction.

(Embodiment 2) In this embodiment, as shown in FIG. 5, the reflecting mirror 2 is formed in a saddle shape and the inner surface is made a reflecting surface. The cross section of the reflecting surface including the x direction shown in FIG. 5 is formed in a convex shape, and the cross section of the reflecting surface including the y direction shown in FIG. 5 is formed in a concave shape. The reflecting mirror 2 is intended to store the left and right directions in an image in a specific region of the object space captured by the TV camera 1.

Now, as shown in FIG. 5 (a), it is assumed that the character C of "A" is written on the surface of interest in the object space, and that the character C is used in the reflecting mirror 2 used in the configuration of the first embodiment. 5C, the left and right of the character C ″ are reversed in the image of the TV camera 1 as shown in FIG. 5C. By using the reflecting mirror 2 having the reflecting surface of, the horizontal direction of the surface of interest in the object space is preserved,
As shown in FIG. 5B, the character C 'in the image is correctly displayed in the image. Other configurations and operations are the same as those of the first embodiment.

(Embodiment 3) In this embodiment, as shown in FIG. 6, a marker 2a which is reflected in the image of the TV camera 1 and indicates a reference position in the image is provided on the reflecting surface of the reflecting mirror 2. Things. In the illustrated example, the marker 2a is formed in a lattice pattern, but a cross-shaped or rectangular marker 2a may be formed,
Alternatively, the marker 2a can be formed so as to indicate a point. The marker 2a can be provided by printing on the reflecting surface of the reflecting mirror 2 or by forming minute irregularities on the reflecting surface. By providing such a marker 2a, it is possible to easily confirm whether or not the direction of the TV camera 1 is suitable for photographing the target area in the object space.

More specifically, when the photographing device of the present embodiment is attached to the rear part of the car, and the line L marked on the ground of the parking lot is photographed by the TV camera 1 as shown in FIG. In the image picked up by the TV camera 1, an image 2a 'of the marker 2a corresponding to the marker 2a is reflected as shown in FIG. Then, the driver of the car
If the driver drives the vehicle so that the image L 'of the line L follows the image 2a' of a, the vehicle can be easily guided to an appropriate position in the parking lot. Other configurations and operations are the same as those of the first embodiment.

In each of the above-described embodiments, an example in which the TV camera 1 is used as the camera has been described. However, the technical idea of the present invention can be applied to a case where a general camera using a photographic photosensitive material is used.

[0023]

According to the first aspect of the present invention, a reflecting mirror having a reflecting surface which enables an image of a region of interest in an object space to be photographed in a desired region in the field of view of the camera is arranged between the camera and the object space. The reflecting surface of the reflecting mirror is formed such that the dimensional ratio along the plane of interest in the object space matches the dimensional ratio in at least one direction of the image taken by the camera. Since the shape of the surface is set so that the dimensional ratio in at least one direction of the captured image coincides with the dimensional ratio along the surface of interest in the object space, image distortion is reduced and visual recognition is easy. Images can be taken. That is, it is possible to recognize an almost accurate shape and size of an entity in an object space without performing computer image processing such as correcting image distortion on an image captured by a camera. as a result,
When a TV camera is used as a camera, the load required for image correction by computer image processing is small, and even if an inexpensive microcomputer with low processing capability is used, it is possible to obtain a smooth moving image with an image with little distortion. There is. In addition, when a camera is used for photographing a photographic photosensitive material, a wide-field image without distortion that could not be photographed even with a wide-angle lens can be photographed. There is an advantage that it is possible to obtain a photograph suitable for the purpose of obtaining an indication of the distance and the size of the object.

According to a second aspect of the present invention, in the first aspect of the present invention, the reflecting surface of the reflecting mirror is adjusted so that an image photographed by the camera is an orthographically projected image of a surface of interest in an object space. Since the image is obtained by orthographically projecting the surface of interest in the image, the distance between objects in the object space and the distance between objects in the image have a proportional relationship. There is an advantage that it is possible to accurately reflect the distance of an existing object and the size of an object in an image.

According to a third aspect of the present invention, in the first aspect of the present invention, the reflecting surface of the reflecting mirror is formed such that an image photographed by the camera is an image obtained by perspectively projecting a plane of interest in an object space. Since an image obtained by perspectively projecting the surface of interest in the image is obtained, there is an advantage that the image is given a perspective. That is, if the camera is mounted near the ground and mounted near the ground, the perspective is given so that the top of the image can be seen in the distance,
By setting the field of view such that the road surface near the car is photographed at the lower part and the upper part of the image is photographed on the road surface far from the car, it is possible to obtain an image with perspective corresponding to the human visual characteristics. Will be possible.

According to a fourth aspect of the present invention, in the first to third aspects of the present invention, a specific direction of a plane of interest in an object space is preserved in an image taken by the camera. One cross section of the reflecting surface of the reflecting mirror is formed in a concave shape, and the direction of the surface of interest in the object space and the direction of the surface in the image can be made coincident in a specific direction. That is, when the camera shoots the target area of the object space through the reflecting mirror, the left and right directions are generally reversed, but by using the reflecting mirror designed so that the cross section including the left and right directions is concave, the left and right directions are in the object space. Can be saved in the image.

According to a fifth aspect of the present invention, in the first to fourth aspects, the reflection surface is provided with a marker which is reflected in an image taken by the camera and indicates a reference position of the image. In addition, there is an advantage that it is possible to easily confirm whether or not the direction of the camera is suitable for photographing the target area in the object space. For example, if this photographing device is attached to a car, the car can be easily guided to an appropriate position by driving the vehicle so that characters and lines written on the road surface match the markers in the parking lot.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a perspective view showing a reflecting mirror used in the embodiment.

FIG. 3 is an operation explanatory diagram of the above.

FIG. 4 is an operation explanatory view of the above.

5A is a schematic perspective view showing a second embodiment of the present invention, FIG. 5B is an operation explanatory view of the same, and FIG. 5C is an operation explanatory view of the first embodiment.

FIG. 6A is a schematic perspective view showing a third embodiment of the present invention, and FIG.

FIG. 7 is an operation explanatory view showing a comparative example.

[Explanation of symbols]

 1 camera 2 reflector 2a marker

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H04N 5/225 H04N 5/225 C // G08B 13/196 G08B 13/196 (72) Inventor Takeshi Maeda Konohana-ku, Osaka-shi No. 3 Kasuga Ichikita 3-chome 4 Height Tsumire 201 (72) Inventor Nobuo Yamato 2-2-18 Shimodera, Naniwa-ku, Osaka V-Stone Co., Ltd. F-term (reference) 2H101 FF00 2H105 CC01 5C022 AA01 AC42 AC51 AC54 5C084 AA02 AA07 AA13 BB21 CC16 DD12 EE01 EE02 EE05 FF01 GG78

Claims (5)

[Claims] 1. A reflecting mirror having a reflecting surface that enables an image of a region of interest in an object space to be captured in a desired region in a field of view of a camera is disposed between the camera and the object space, and a surface to be focused on in the object space. A reflecting surface of a reflecting mirror is formed such that a dimensional ratio along a distance in at least one direction of an image captured by a camera matches the dimensional ratio. 2. An image photographed by the camera is an orthographically projected image of a plane of interest in an object space,
2. The photographing apparatus according to claim 1, wherein a reflecting surface of the reflecting mirror is formed. 3. An image photographed by the camera is a perspective projection image of a plane of interest in an object space.
2. The photographing apparatus according to claim 1, wherein a reflecting surface of the reflecting mirror is formed. 4. A cross section of one of the reflecting surfaces of the reflecting mirror is formed in a concave shape so that a direction in a plane of interest in an object space in an image taken by the camera is preserved. The photographing apparatus according to any one of claims 1 to 3, wherein: 5. The image forming apparatus according to claim 1, wherein a marker is provided on the reflection surface, the marker being reflected in an image captured by the camera and indicating a reference position of the image. An imaging device according to item 1.