JP2005086287A - Stereoscopic video imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stereoscopic video imaging apparatus capable of converging a light with a miniaturized apparatus without requiring a complicated optical system. <P>SOLUTION: The apparatus is provided with an optical fiber group 1 formed in a planar shape by regularly bundling and disposing a plurality of optical fibers 2, each having a refractive index distribution in which a refractive index becomes larger from the peripheral edge to an optical axis; an incident lens 6 facing the lens group 1, and having a dimension smaller than the dimension of the lens group 1; and an imaging means 5 for imaging each element image formed by the lens group 1 through the incident lens 6. The lens group 1 is provided with a oblique emission end surface 2b through which an emitted light travels along an optical path toward the incident lens 6 in an optical fiber 2(m) to be disposed on a position placed away from an optical axis O1 of the incident lens 6. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a stereoscopic video imaging apparatus applied to a stereoscopic video system using a so-called IP (Integral Photography) system.

  Conventionally, as a stereoscopic video system, a system that does not use polarized glasses or the like has been developed and studied. As a three-dimensional stereoscopic display technology that does not rely on polarized glasses, etc., a device using a lenticular plate has already been commercialized, and furthermore, a three-dimensional stereoscopic image that can be recognized from the top, bottom, left and right, which is impossible with the lenticular method, is obtained. The IP system that can be used is being put into practical use. As this IP system, a system using lens groups or pinhole groups arranged in a plane is known.

The configuration of the IP system and the principle of stereoscopic display will be described with reference to FIG. 15 and FIG.
FIG. 15 is a diagram for explaining a subject imaging method in the conventional IP method, and FIG. 16 is a diagram for explaining a stereoscopic image observation method in the conventional IP method.
As shown in FIG. 15, the lens group 50 includes a plurality of convex lenses (hereinafter, each convex lens is referred to as element lenses 50 ₁ , 50 ₂ ... 50 _n ) having an action of forming an image of the subject 51. A film F or the like is disposed at the rear focal position of the lens group 50, and a plurality of images of the subject 51 (hereinafter referred to as individual images 51 ₁ , 51 ₂ ... 51 _n formed through the lens group 50). Is captured). This lens group 50 is usually constituted by arranging several hundred or more minute lenses on the same plane in the vertical and horizontal directions. In the figure, only one representative element lens 50 ₁ , 50 ₂ ... 50 _n is shown. Is illustrated.

It is assumed that the subject 51 is placed in front of the lens group 50 with a distance sufficiently larger than the focal length of each of the lenses 50 ₁ , 50 ₂ ... 50 _n . The light emitted from the subject 51 forms an inverted image of the subject 51 by the action of the lenses 50 ₁ , 50 ₂ ... 50 _n .
Each element image 51 ₁ , 51 ₂ ... 51 _n is a slightly different image due to the difference in position of each element lens 50 ₁ , 50 ₂ ... 50 _n . Information on the depth in the stereoscopic image is given.

The element images 51 ₁ , 51 ₂ ... 51 _n thus imaged are three-dimensionally reproduced by the eyes of the observer H through the lens group 50 arranged at the same position as when imaging, as shown in FIG. It appears as an image 51 ′. That is, light emitted from the element image 51 _1, 51 ₂ ... 51 _n by the action of the corresponding element lenses 50 _1, 50 ₂ ... 50 _n, to form a three-dimensional reconstruction image 51 'in front of the lens group 50 ( For example, see Patent Document 1).

In practice, when the observer H views the stereoscopic reproduction image 51 ′ in the state of FIG. 16, it becomes a virtual stereoscopic image that appears to be reversed in depth. Therefore, the correct three-dimensional image of the depth, the center of each element image 51 _1, 51 ₂ ... 51 _n as the center of point symmetry, so obtained by performing position conversion processing of symmetrical points by separate means ( For example, JP-A-10-150675.

By the way, an optical fiber lens group using an optical fiber (refractive index distribution lens) is known as one having a lens action instead of such a convex lens. This optical fiber lens group is configured by collecting a plurality of optical fibers having a predetermined cylindrical shape, and each optical fiber has a length at which an erect image of a subject is formed on the exit end face. According to such an optical fiber lens group, not only can the unevenness of the stereoscopic image be displayed in a correct state, but also an advantage that interference of light between adjacent element pixels can be avoided.
JP-A-8-289329 (paragraph 0012, FIG. 1)

  In the IP method using the conventional optical fiber lens group, a stereoscopic image is obtained by directly capturing each element image. However, in order to obtain a stereoscopic image without distortion as in film imaging, It is desirable to capture an element image by an imaging method equivalent to that when film imaging is performed.

That is, in the conventional imaging method shown in FIGS. 15 and 16, when an optical fiber lens group is used instead of the lens group 50, the film F is made of each optical fiber 53 ₁ of the optical fiber lens group 53 as shown in FIG. 17. , 53 ₂ ... 53 _n must be large enough to capture all the element images G1, G2,.
Therefore, instead of using the film F, in order to realize this by a method of imaging each element image of the optical fiber lens group 53, as shown in FIG. 18, all the element images G1, G2,. A large camera lens L that can be used is required.

  Therefore, when the optical fiber lens group 53 is formed large so that a wider range of stereoscopic images can be obtained, the lens diameter of the camera lens L of the imaging device S must be increased accordingly. There has been a problem that the imaging apparatus S is increased in size.

As a measure for avoiding such an increase in the size of the imaging device S, a convex lens L1 formed larger than the optical fiber lens group 53 is disposed behind the optical path of the optical fiber lens group 53 as shown in FIG. If each of the element images G1, G2,... Gn is taken into the imaging device S via L1, the camera lens L2 of the imaging device S can be made relatively small.
However, in this method, it is necessary to make the distance W1 between the convex lens L1 disposed behind the optical path of the optical fiber lens group 53 and the camera lens L2 of the imaging device S coincide with the focal length of the convex lens L1 (for details, refer to electronic information communication). Society Technical Research Report vol.95 No.581 IE95-146).
For this reason, there exists a difficulty that an optical system becomes complicated.

  In view of the above problems, an object of the present invention is to provide a stereoscopic video imaging apparatus that does not require a complicated optical system and that can reduce the size of the imaging apparatus.

  In order to achieve the above object, a stereoscopic video imaging apparatus according to the present invention includes an optical fiber lens group, an incident lens, and an imaging means, and the optical fiber lens group is disposed at a position away from the optical axis of the incident lens. The optical fiber is configured to have an inclined outgoing end face in which the outgoing light from the optical fiber follows the optical path toward the incident lens.

According to this stereoscopic image pickup device, the outgoing light from the optical fiber arranged at a position away from the optical axis of the incident lens is refracted by a predetermined angle at the inclined outgoing end face and is emitted toward the incoming lens.
Thereby, the element images formed by the optical fibers of the optical fiber lens group can be converged toward the incident lens. Then, each element image converged toward the incident lens is picked up by the image pickup means.

  The stereoscopic image capturing apparatus according to the present invention includes an optical fiber lens group, an incident lens, and an imaging unit, and the optical fiber lens group allows the outgoing light from each optical fiber to follow an optical path toward the incident lens. In addition, the emission end face as the optical fiber lens group is formed in a Fresnel lens shape.

According to this stereoscopic image pickup apparatus, the outgoing light from each optical fiber is refracted by a predetermined angle at the outgoing end face formed in a Fresnel lens shape and is emitted toward the incident lens.
Thereby, the element images formed by the optical fibers of the optical fiber lens group can be converged toward the incident lens. Then, each element image converged toward the incident lens is picked up by the image pickup means.

  Furthermore, the stereoscopic image capturing apparatus according to the present invention includes an optical fiber lens group, an incident lens, and an imaging unit, and the optical fiber lens group is configured so that outgoing light from each optical fiber follows an optical path toward the incident lens. The exit end face as the optical fiber lens group is formed in a curved surface having a predetermined radius of curvature from the center of the surface toward the edge side (Claim 3).

According to this stereoscopic image pickup apparatus, the outgoing light from each optical fiber is refracted by a predetermined angle at the outgoing end face formed in a curved surface and is emitted toward the incident lens.
Thereby, the element images formed by the optical fibers of the optical fiber lens group can be converged toward the incident lens. Then, each element image converged toward the incident lens is picked up by the image pickup means.

  According to the three-dimensional image pickup device of the first aspect, since the outgoing light of each optical fiber can be converged on the incident lens facing the optical fiber lens group, the optical fiber lens group can have the same function as the convex lens. . Therefore, it is not necessary to separately arrange a large convex lens as in the prior art, the optical system is simplified, and the image pickup apparatus can be reduced in size.

  According to the stereoscopic image pickup apparatus of the second aspect, since the exit end face as the optical fiber lens group is formed in a Fresnel lens shape, the outgoing light of each optical fiber can be converged on the incident lens facing the optical fiber lens group. Thus, it is not necessary to separately arrange a large convex lens as in the prior art, the optical system is simplified, and the imaging apparatus can be reduced in size.

  According to the three-dimensional image pickup device according to claim 3, the exit end face as the optical fiber lens group is formed in a curved surface having a predetermined radius of curvature from the center of the surface toward the edge side, and is incident on the optical fiber lens group. Since the light emitted from each optical fiber can be converged on the lens, the optical fiber lens group can be used as one convex lens. Therefore, it is not necessary to separately arrange a large convex lens as in the prior art, the optical system is simplified, and the image pickup apparatus can be reduced in size.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the description, the same reference numerals are used for the same elements, and duplicate descriptions are omitted.

(First embodiment)
FIG. 1 is a schematic diagram for explaining a stereoscopic video imaging apparatus according to the first embodiment of the present invention, and FIG. 2 is a part of an optical fiber lens group and an imaging apparatus for explaining the locus of emitted light. It is the schematic diagram which showed.

  As shown in FIG. 1, the stereoscopic image pickup apparatus of the present embodiment includes an optical fiber lens group 1, an incident lens 6 and an image pickup plate 7 serving as an image pickup unit disposed behind the optical path of the optical fiber lens group 1. And an imaging device (video camera or the like) 5 provided.

The optical fiber lens group 1 is formed in a planar shape by regularly bundling a plurality of optical fibers 2, and each optical fiber 2 has a refractive index distribution in which the refractive index increases from the peripheral portion toward the optical axis. Something is used. As shown in FIG. 2, the optical fiber lens group 1 includes an optical fiber (for example, an optical fiber 2 (m) located at the m-th from the optical axis O1) disposed at a position away from the optical axis O1 of the incident lens 6. The emission end face 2b is formed in an inclined shape.
The inclination angle θm of the outgoing light a ₁ ″ with respect to the optical axis Km at the outgoing end face 2b is obtained as described later. By having such an inclination angle θm, the outgoing light a ₁ in the optical fiber 2 (m) is obtained. ″ Follows the optical path toward the principal point 6 a of the incident lens 6 of the imaging device 5. As a result, light (element image) equivalent to that for film imaging can be captured by the small-diameter incident lens 6 of the imaging device 5.

  Referring to FIG. 1 again, the imaging device 5 includes the incident lens 6 and an imaging plate 7 made of an imaging element. The incident lens 6 faces the optical fiber lens group 1 and has an outer diameter smaller than the outer diameter of the optical fiber lens group 1. Specifically, for example, a size about 1/5 of the outer diameter of the optical fiber lens group 1 can be used. As described above, the light from each optical fiber 2 of the optical fiber lens group 1 is converged on the incident lens 6 by, for example, the action of the inclination angle θm of the outgoing light on the outgoing end face 2b. The light incident on the incident lens 6 is emitted toward the rear imaging plate 7 in the imaging device 5.

  Here, the image pickup plate 7 of the image pickup apparatus 5 is for picking up a plurality of element images incident on the incident lens 6, and is composed of, for example, an optical element such as a CCD (Charge Coupled Device). The imaging plate 7 is disposed at a position spaced a predetermined distance from the exit end face 6 b of the incident lens 6.

Next, the optical fiber lens group 1 will be described in more detail.
Each optical fiber 2 used in the optical fiber lens group 1 of the present embodiment has a refractive index distribution in which the refractive index increases from the peripheral portion toward the optical axis, the lens length is Z, and the refractive index distribution constant. Is √A, the relationship between Z and √A is

The relationship represented by
Here, the optical fiber lens group 1 of the present embodiment will be described in comparison with the optical fiber lens group 20 constituted by a general optical fiber 10 whose output end face 10b is not processed as shown in FIG. Then it becomes as follows. That is, in the general optical fiber lens group 20, the outgoing light spreads in the diffused state on the outgoing end face 10b. Now, of the plurality of optical fibers 10 regularly arranged, the optical fiber 10 (m) at the m-th position counted from the optical axis O1 of a camera lens (not shown) that images the optical fiber lens group 20 is selected. m) Considering the outgoing light (a ₁ ′, b ₁ ′, c ₁ ′) when light (a ₁ , b ₁ , c ₁ ) parallel to the optical axis K1 enters, the optical fiber 10 (m) The incident light travels along a locus according to the matrix expressed by the following equation (2) (for details, The Bell System Technical Journal, vol. 43, July. 1964, pp1759-1782).

In the above formula (2), n (0) is the refractive index of the optical fiber, r ₁ and r ₁ ′ are the incident position and angle on the incident end face of the light incident on the optical fiber, and r ₂ and r ₂ ′. These respectively show the outgoing position and outgoing angle of the light emitted from the optical fiber on the outgoing end face.
As shown in FIG. 3, on the incident end face 10a of the optical fiber 10 (m), the light beam a ₁ incident along the optical axis K1 is from the optical axis K1 of the optical fiber 10 (m) to the optical axis of the optical fiber 10 (m). It becomes a light ray a ₁ ′ emitted along K1. Also, at the incident end face 10a of the optical fiber 10 (m), light b _1, c ₁ which is incident parallel to the optical axis K1 is an optical fiber 10 (m) beam b ₁ emitted from the optical axis K1 at a predetermined angle of ' , C ₁ '.
Here, the locus of the outgoing light (a ₁ ′, b ₁ ′, c ₁ ′) in the optical fiber 10 (m) can be examined by applying Snell's law on the outgoing end face 10 b.

That is, as shown in FIG. 4, the light beam traveling from the inside of the optical fiber 10 (m) to the outside of the optical fiber 10 (m) is caused by the locus of the light beam traveling from the medium having the refractive index n _{1 to} the medium having the refractive index n _2. As can be explained, the light beam AB incident at an angle θ1 with respect to the normal line 11a of the output end face 10b becomes a light beam BC traveling at an angle θ2 with respect to the normal line 11a at the output end face 10b.
Here, the point A is a point on the light beam in the optical fiber 10 (m), the point B is the arrival point of the light beam on the emission end surface 10b, and the point C is a point on the locus of the light beam emitted from the emission end surface 10b. ing. At this time, the relationship represented by the following equation (3) is established.

At this time, if sin θ ₁ is about θ ₁ and sin θ ₂ is about θ ₂ ,

It becomes. Based on this, the locus of the outgoing light of the optical fiber 2 (m) whose outgoing end face 2b (see FIG. 2) is inclined as in the present embodiment can be described. As shown in FIG. 5, the exit end face 2b is inclined counterclockwise by an angle δ with respect to the exit end face 10b with reference to a point B where the same ray AB as the ray AB shown in FIG. 4 reaches the exit end face 10b. If this is the case, the incident light beam AB proceeds as a light beam BC ′ having an angle θ ₂ ′ with respect to the normal line 2b ′ of the tilted outgoing end face 2b. The relationship at this time is expressed by the following equation (5).

At this time, if sin θ ₁ ′ is about θ ₁ ′ and sin θ ₂ ′ is about θ ₂ ′,

Furthermore, if the angle formed by the light beam BC ′ and the normal line 11a of the emission end face 10b is θ ₂ ″,

The relationship becomes. Therefore, the angle difference η between θ ₂ ″ and θ ₂ can be obtained by the following equation (8).

This indicates that when the outgoing end face 10b is tilted by an angle δ with respect to the point B where the light beam reaches, the outgoing light changes by the angle η given by the equation (8).
Therefore, as shown in FIG. 2, the light beam a ₁ ″ of the optical fiber 2 (m) is incident on the principal point 6a of the incident lens 6 of the imaging device 5 located at a position _Zf away from the emission end face 2b of the optical fiber lens group 1. In order to achieve this, the exit end face 2b in which the inclination angle θm of the light ray a ₁ ″ with respect to the optical axis Km is an angle η (m, 0) given by the following equation (9) may be formed. That is, if the lens radius of the optical fiber 2 is r and the lens number of the optical fiber 2 (m) is m,

  Thus, in the optical fiber 2 (m) having the lens number m, it is only necessary to form the emission end face 2b having the angle η (m, 0). Therefore, according to the above equation (8), when the refractive index on the optical axis of the optical fiber 2 is n (0) and the optical fiber lens group 1 is disposed in the atmosphere, the angle δ (m, If the outgoing end face 2b of the optical fiber 2 is inclined by 0), the outgoing light from the outgoing end face 2b follows an optical path that is refracted toward the principal point 6a of the incident lens 6 of the imaging device 5 behind the optical path. Become.

As described above, out of the parallel light (a ₁ , b ₁ , c ₁ ) incident in parallel to the optical axis Km of the optical fiber 2 (m), the output in the light ray a ₁ incident along the optical axis Km is obtained. Although the locus of the incident light has been described, other parallel light (b ₁ , c ₁ ) is also refracted at the same angle and can be converged with respect to the incident lens 6.
Therefore, according to the optical fiber lens group 1 as described above, it is possible to provide the same effect as when a large-diameter convex lens is disposed behind the optical path of the optical fiber lens group 1, and the incident lens 6 of the imaging device 5. It is possible to converge the outgoing light emitted from the outgoing end face of each optical fiber 2 of the optical fiber lens group 1 (for example, the outgoing end face 2b in the optical fiber 2 (m)) to the principal point 6a.

(Second embodiment)
FIG. 6 is a schematic diagram showing a part of an optical fiber lens group and an imaging apparatus for explaining a stereoscopic video imaging apparatus showing a second embodiment according to the present invention.
In the present embodiment, as shown in FIG. 6, the output end face 31 b of each optical fiber 31 is formed so that the emitted light from each optical fiber 31 of the optical fiber lens group 30 follows the optical path toward the incident lens 6 of the imaging device 5. The point that is formed obliquely with the inclination is the same, but the inclination is formed so as to be a Fresnel lens shape having fine inclined unevenness as the exit end face of the optical fiber lens group 30. Is different from the first embodiment.
Then, the finely inclined irregularities of the Fresnel lens shape are formed so that the inclination angle continuously increases from the center of the optical fiber lens group 30 toward the edge side.

As shown in FIG. 6, in such an optical fiber lens group 30, even when parallel light (a ₂ , b ₂ , c ₂ ) having an angle of θ _d with respect to the optical axis Km is incident, imaging is performed. The emitted light can be converged with respect to the incident lens 6 of the device 5.

Here, the optical fiber lens group 30 of the present embodiment will be described as follows, as compared with a general optical fiber 10 whose output end face 10b is not processed as shown in FIG. That is, in the general optical fiber 10, the parallel light (a ₂ , b ₂ , c ₂ ) having an angle θ _d with respect to the optical axis K is the position of r ₂ displaced from the optical axis K of the emission end face 10b. From the above equation (2), the light beam is emitted at an angle of θ _d ′ up and down around the emitted light a ₂ ′ emitted in the direction parallel to the optical axis K.

Therefore, as shown in FIG. 6, consider the locus of the light beam of the optical fiber 31 (m) at the m-th position away from the optical axis O <b> 1 of the imaging device 5 among the optical fibers 31 of the optical fiber lens group 30. And the following. That is, when parallel light (a ₂ , b ₂ , c ₂ ) having an angle θ _d with respect to the optical axis Km of the optical fiber 31 (m) is incident, among these, the optical axis Km of the optical fiber 31 (m) In order to make the incident light a ₂ incident on the incident lens 6 of the imaging device 5, the light beam may be refracted by an angle η (m, r ₂ ) obtained by the following equation (11). Here, the emission position r ₂ in the following equation (11) is −r ₂ because it is on the optical axis O 1 side of the incident lens 6 with respect to the optical axis Km of the optical fiber 31 (m).

Therefore, when the refractive index of the optical fiber 31 (m) at the position r ₂ away from the optical axis Km at the exit end face 31b is n (r ₂ ), the inclination angle δ (m, r ₂ ) is represented by the following equation (12).

Therefore, as shown in FIG. 8, the inclination of the angle δ (m, r ₂ ) expressed by the above equation (12) is formed on the emission end face 31b of the optical fiber 31 in increments of a predetermined pitch p. As a result, the parallel light a ₂ enters the incident lens 6 of the imaging device 5. In this case, the same result is obtained for the other parallel light (b ₂ , c ₂ ). The pitch P and the step depth d are set to a size that does not affect the imaging state. In addition, when the aperture of the incident lens 6 of the imaging device 5 is small compared to the spread of the rays b ₂ and c ₂ , a phenomenon that the amount of light is lost occurs. In such a case, a large-diameter convex lens for converging the spread of rays b ₂ and c _{2 to} the incident lens 6 at an appropriate position in front of the incident lens 6 at the rear of the optical path of the optical fiber lens group 30. Need to be placed. Therefore, it is desirable to set the aperture of the incident lens 6 in consideration of the spread of the rays b ₂ and c ₂ (for details, refer to IEICE Technical Report vol.95 No.581 IE95-146). .

  Up to this point, when the length of the optical fiber is Z and the refractive index distribution constant is √A, the relationship between Z and √A is

Next, using a large-diameter convex lens by forming an inclination similar to that of the equation (12) on the output end face of the optical fiber, also in cases other than the equation (1), It is possible to have an equivalent action.
This will be described in comparison with a general optical fiber 10 whose output end face 10b is not processed as shown in FIGS. Here, in general, an optical fiber has a property in which an emission angle varies depending on the length of the optical path (the length of the optical fiber), so that the optical path is expressed by the following equations (13) to (14), Consider four areas.

9 to 12, r _1a , r _1b and r _1c are the incident positions on the incident end face 10a of the parallel light (a, b, c), and r _1a ′, r _1b ′ and r _1c ′ are the parallel light. The incident angles r _2a , r _2b and r _2c of the incident end face 10a of (a, b, c) are the emission positions on the emission end face 10b of the parallel light (a, b, c), r _2a ′, r _2b ′. , R _2c ′ represents the exit angle of the parallel light (a, b, c) on the exit end face 10b. The angle is positive in the counterclockwise direction with respect to the optical axis K of the optical fiber 10. The incident angles r _2a , r _2b , and r _2c are the same because they are parallel light. According to the above formula (2),

It becomes. Therefore, in any of the above formulas (13) to (16), the emitted light b′c ′ is, for example, from the position of r _2a with reference to the emitted light a ′ as shown in FIG. From the position on the exit end face that is separated by an equal distance ε represented by the following equation (20), the same angle ε ′ (not shown) represented by the following equation (21) is centered around r _2a ′. Inclined and emitted.

すなわち、これらのことから、出射光ａ’の出射端面１０ｂ上の位置ｒ_2aに対して、前記式（１２）のδ（ｍ，ｒ₂）で表される角度の傾斜を施せば、前記式（１）の場合以外の光ファイバーに対して、大口径凸レンズを用いることと同様の作用をもたせることができるようになる。
したがって、前記式（１）以外の場合にも、例えば、光ファイバー３１の出射端面３１ｂと同様に、前記式（１２）で求められる傾斜を形成することにより大口径凸レンズを用いることと同等の作用をもたせることが可能である。
なお、ピッチｐと刻みの深さｄは、結像状態に影響を与えない程度の大きさとされている。
ここでは、前記式（１２）で表されるδ（ｍ，ｒ₂）は、ｒ₂をｒ_2aとして算出する（図８参照）。

That is, from these facts, if the inclination of the angle represented by δ (m, r ₂ ) in the equation (12) is applied to the position r _2a on the emission end face 10b of the emission light a ′, the equation With respect to the optical fiber other than the case of (1), it becomes possible to have the same effect as using the large-diameter convex lens.
Therefore, in the case other than the above formula (1), for example, similarly to the emission end face 31b of the optical fiber 31, the same effect as using the large-diameter convex lens by forming the slope obtained by the above formula (12) is obtained. It can be given.
Note that the pitch p and the step depth d are set to a size that does not affect the imaging state.
Here, [delta] is expressed by the formula (12) (m, r ₂₎ calculates r ₂ as r _2a (see FIG. 8).

(Third embodiment)
FIG. 13 is a schematic diagram showing an optical fiber lens group and an imaging apparatus for explaining a stereoscopic video imaging apparatus showing a third embodiment according to the present invention.
In the present embodiment, as shown in FIG. 13, the exit end face as the optical fiber lens group 40 so that the outgoing light from each optical fiber 41 of the optical fiber lens group 40 follows the optical path toward the incident lens 6 of the imaging device 5. The point which formed 40b in the curved surface shape which has a predetermined curvature radius toward the edge side from a planar center differs from said 1st, 2nd embodiment.
In other words, the optical fiber lens group 40 employed in the present embodiment reduces the pitch p to infinitely the unevenness formed by the inclination of δ (m, r ₂ ) expressed by the above formula (12). Thus, the emission end face 40b is formed in a curved shape. For this reason, the √AZ needs to make the pitch p infinitely small, and is therefore limited to that represented by the following equation (22).

  Here, the inclinations of the mth optical fiber 41 (m) and the m−1th optical fiber 41 (m−1) that are separated from the optical axis O1 of the incident lens 6 are as follows according to the equation (12). Become. Here, the inclination when the emission position on the emission end face 41 (m) b of the optical fiber 41 (m) is displaced −r from the optical axis (not shown) is δ (m, −r), and the optical fiber 41 (m− Assuming that the inclination when the exit position on the exit end face 41 (m-1) b of 1) is displaced from the optical axis (not shown) by r is δ (m-1, r),

となる。ここで、一般的に、光ファイバーでは、ｎ（−ｒ）＝ｎ（ｒ）となるので、前記式（２３）と式（２４）とにより、

It becomes. Here, in general, in an optical fiber, since n (−r) = n (r), the above equation (23) and equation (24)

It becomes. This indicates that the emission end faces (for example, the emission end face 41 (m) b and the emission end face 41 (m-1) b) of the optical fibers 41 adjacent to each other are connected by a continuous curved surface.
FIG. 14 is a schematic enlarged view of the optical fiber 41. The optical fiber 41 is processed so that the tangent slope becomes a curved surface represented by δ (m, r ₂ ) shown in the above formula (12). 41b. In such an optical fiber lens group 40 (see FIG. 13) using the optical fiber 41, the output end face 40b is formed in a curved surface having a predetermined radius of curvature as a whole, thereby using a large-diameter convex lens. The same operational effect as when there was.

  In addition, when the process which makes the output end surface 40b become a curved surface like this Embodiment, the lens length (Z) of the optical fiber 41 which comprises the optical fiber lens group 40 changes with positions. . For this reason, depending on the optical fiber 41, the value of √AZ may be different from the value described in the equation (22). In this case, if the difference from the value obtained by the equation (22) becomes relatively large, the resolution of the element image formed by each optical fiber 41 is deteriorated. Therefore, the condition of the equation (22) is satisfied. Thus, it is desirable to respond by changing √A of each optical fiber 41.

It is a schematic diagram for demonstrating the three-dimensional video imaging device which concerns on 1st embodiment of this invention. Similarly, in order to explain the locus of the emitted light, it is a schematic diagram showing a part of the optical fiber lens group and the imaging device. It is a schematic diagram which shows the optical fiber lens group using the general optical fiber by which the output end surface is not processed at all. It is a schematic diagram for demonstrating the locus | trajectory of emitted light. It is a schematic diagram for demonstrating the locus | trajectory of emitted light. It is the schematic diagram which showed a part of optical fiber lens group and imaging device for demonstrating the three-dimensional video imaging device which shows 2nd embodiment which concerns on this invention. It is a model enlarged view which shows the incident light and outgoing light in the general optical fiber with which the output end surface is not processed at all. It is a model enlarged view for demonstrating the optical fiber in 2nd embodiment. It is a model enlarged view which shows the general optical fiber with which no output end surface is processed. It is a model enlarged view which shows the general optical fiber with which no output end surface is processed. It is a model enlarged view which shows the general optical fiber with which no output end surface is processed. It is a model enlarged view which shows the general optical fiber with which no output end surface is processed. It is the schematic diagram which showed the optical fiber lens group and imaging device for demonstrating the three-dimensional video imaging device which shows 3rd embodiment which concerns on this invention. It is a model enlarged view of the optical fiber which concerns on 3rd embodiment. It is a figure for demonstrating the conventional IP system. It is a figure for demonstrating the reproducing method of the stereo photograph by the conventional IP system. It is explanatory drawing of the technique using the conventional optical fiber lens group. It is explanatory drawing of the technique using the conventional optical fiber lens group. It is explanatory drawing of the technique using the conventional optical fiber lens group.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical fiber lens group 2 Optical fiber 2a Incidence end surface 2b Outgoing end surface 5 Imaging device 6 Incident lens 6a Main point 7 Imaging board (imaging means)
DESCRIPTION OF SYMBOLS 10 Optical fiber 10a Incident end surface 10b Outgoing end surface 20 Optical fiber lens group 30 Optical fiber lens group 31 Optical fiber 31b Outgoing end surface 40 Optical fiber lens group 41 Optical fiber 41b Outgoing end surface O1 Optical axis

Claims (3)

A plurality of optical fibers having a refractive index distribution in which the refractive index increases from the peripheral edge toward the optical axis, and arranged in a plurality of regular bundles, facing the optical fiber lens group formed as a planar shape, A stereoscopic video imaging apparatus comprising: an incident lens having an outer dimension smaller than the outer dimension of the optical fiber lens group; and an imaging unit that images each element image formed by the optical fiber lens group through the incident lens. And
The optical fiber lens group includes an inclined emission end face in which the emitted light from the optical fiber follows an optical path toward the incident lens in the optical fiber arranged at a position away from the optical axis of the incident lens. A featured stereoscopic video imaging device. A plurality of optical fibers having a refractive index distribution in which the refractive index increases from the peripheral edge toward the optical axis, and arranged in a plurality of regular bundles, facing the optical fiber lens group formed as a planar shape, A stereoscopic video imaging apparatus comprising: an incident lens having an outer dimension smaller than the outer dimension of the optical fiber lens group; and an imaging unit that images each element image formed by the optical fiber lens group through the incident lens. And
The optical fiber lens group is formed of a Fresnel lens in an output end face as the optical fiber lens group so that outgoing light from each optical fiber follows an optical path toward the incident lens. apparatus. A plurality of optical fibers having a refractive index distribution in which the refractive index increases from the peripheral edge toward the optical axis, and arranged in a plurality of regular bundles, facing the optical fiber lens group formed as a planar shape, A stereoscopic video imaging apparatus comprising: an incident lens having an outer dimension smaller than the outer dimension of the optical fiber lens group; and an imaging unit that images each element image formed by the optical fiber lens group through the incident lens. And
The optical fiber lens group has a predetermined radius of curvature from the center to the edge side of the output end surface as the optical fiber lens group so that outgoing light from each optical fiber follows an optical path toward the incident lens. A stereoscopic video imaging apparatus characterized by being formed into a curved surface.

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