JP5452800B2 - Stereoscopic imaging device - Google Patents

Description

  The present invention relates to a stereoscopic image capturing apparatus that captures a stereoscopic image of a subject.

  Conventionally, an invention for photographing a stereoscopic image of a subject has been proposed (see, for example, Patent Documents 1 and 2). The invention described in Patent Document 1 performs photographing by an integral photography system using convex lens groups or pinhole groups arranged in a plane. In the invention described in Patent Document 2, light from a subject is separated into two by a light separating means, and photographing is performed with two photographing cameras.

Japanese Patent No. 3836550 (Japanese Patent Laid-Open No. 10-150675) Japanese Patent No. 3676916 (Japanese Patent Laid-Open No. 11-98532)

However, the invention described in Patent Document 1 has a problem that, when shooting a multi-viewpoint image, the number of shooting cameras is the same as the number of viewpoints, and the configuration is complicated. In particular, in the invention described in Patent Document 1, when multi-viewpoint images are taken with convergence (the same subject is shot with a plurality of shooting cameras), the respective shooting cameras are adjusted accurately so that they face the direction of the subject. There is also a problem that it is difficult to do.
Further, the invention described in Patent Document 2 requires a light separating means for separating light and two photographing cameras, and there is a problem that the configuration is complicated.

  Therefore, an object of the present invention is to provide a three-dimensional image photographing device that can be easily adjusted with a simple configuration.

In order to solve the above-described problem, a stereoscopic image photographing apparatus according to the first invention of the present application has a plano- convex lens arranged on the subject side and a refractive index distribution lens arranged two-dimensionally facing the plano- convex lens. A stereoscopic image capturing apparatus comprising: the lens array; and an imaging element that captures an elemental image of the subject facing the lens array, wherein the plano- convex lens includes a convex surface formed on the subject side, And the lens array has the same horizontal and vertical lengths as the plano-convex lens, and the refractive index distribution lens has one end surface which is a flat surface of the plano- convex lens. a abuts against the incident light from the subject entering through the plano-convex lens, wherein an image is formed as an element image while the other opposite the end face of the object to the end surface, said imaging device, A photographing surface for photographing an elemental image of a subject is in contact with the other end surface of the refractive index distribution lens, and an elemental image of the subject formed on the other end surface of the refractive index distribution lens is photographed. To do.

According to this configuration, the stereoscopic image capturing apparatus emits incident light from the subject as parallel light to each of the refractive index distribution lenses by the plano- convex lens. Then, the stereoscopic image photographing device forms an image on the other end surface while periodically meandering the parallel light (incident light) incident on the one end surface by the refractive index distribution lens. Further, the stereoscopic image capturing device captures an element image of the subject formed on the gradient index lens by the image sensor.
Accordingly, the stereoscopic image capturing apparatus can capture an element image of a subject without using a plurality of imaging cameras and light separating means (for example, a prism and a half mirror). In addition, since the three-dimensional image capturing apparatus can capture a single image, it does not require complicated adjustments such that a plurality of photographing cameras are directed toward the subject.

In the stereoscopic image photographing device according to the second invention of the present application, the refractive index distribution lens has a length in the optical axis direction of (2n−1) / 4 of the meandering period of incident light incident on the refractive index distribution lens. (Where n is an integer of 1 or more).
According to such a configuration, the stereoscopic image capturing apparatus can form an element image of the subject as an erect image or an inverted image on the other end face of the gradient index lens.

In the three-dimensional image photographing device according to the third and fourth inventions of the present application, in the refractive index distribution lens, the length in the optical axis direction is 1/4 or 3 of the meandering period of incident light incident on the refractive index distribution lens. / 4.
According to such a configuration, the stereoscopic image capturing apparatus can capture the element image of the subject as an erect image or an inverted image with the refractive index distribution lens as the shortest.

The stereoscopic image capturing device according to the fifth aspect of the present invention further includes element image selection means for selecting two preset element images of the subject from the element images of the subject captured by the image sensor. To do.
According to such a configuration, the stereoscopic image capturing apparatus can select two element images as stereo images (right-eye image and left-eye image) from all the element images captured by the image sensor.

The three-dimensional image photographing device according to the present invention has the following excellent effects.
According to the first invention of the present application, an element image of a subject can be photographed without using a plurality of photographing cameras and light separating means, and a simple configuration can be achieved. Further, the first invention of the present application does not require complicated adjustments such that a plurality of photographing cameras are directed toward the subject, and the adjustment is easy.

The second invention of the present application can capture an inverted image or an erect image of a subject.
According to the third and fourth inventions of the present application, an inverted image or an erect image of a subject can be taken with a simple configuration with a minimum gradient index lens.
The fifth invention of the present application can be applied to binocular stereoscopic vision because a stereo image can be selected from all the element images photographed by the image sensor.

It is a figure which shows the structure of the stereo image imaging device which concerns on 1st Embodiment of this invention. (A) is a front view when the stereoscopic image photographing apparatus of FIG. 1 is viewed from the subject direction, (b) is a cross-sectional view taken along line XX ′ of (a), and (c) is Y of (a). It is -Y 'sectional drawing. It is a figure which shows the structure of the stereo image imaging device which concerns on 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In each embodiment, means having the same function and the same member are denoted by the same reference numerals, and description thereof is omitted.

(First embodiment)
With reference to FIG. 1 and FIG. 2, the structure of the three-dimensional image photographing device according to the first embodiment of the present invention will be described. In the first embodiment, a stereoscopic microscope apparatus 1 will be described as an example of a stereoscopic image capturing apparatus according to the present invention.

In FIG. 1, incident light from the subject A is illustrated by a broken-line arrow. 1 is an element image of the subject A formed on the other end surface 14b of the gradient index lens 14.
Further, in FIG. 2, in order to simplify the description, illustration of a part of the configuration such as the image sensor driving circuit 11 and the multi-viewpoint / stereoscopic image signal processing unit 17 is omitted.

[Configuration of stereo microscope apparatus]
The stereoscopic microscope apparatus 1 captures a stereoscopic image of a subject A, and includes an imaging element driving circuit 11, a convex lens 12, a lens array 13, an imaging element 15, a multi-viewpoint / stereoscopic image signal processing unit 17, An element image selection means 18, a multi-viewpoint / stereoscopic image monitor 19, and a binocular stereoscopic image monitor 20 are provided.

  The image sensor driving circuit 11 is an electronic circuit such as an IC (Integrated Circuit) or an LSI (Large Scale Integration) that drives an image sensor 15 described later. Since this image sensor driving circuit 11 is the same as the conventional one, detailed description thereof is omitted.

  The convex lens 12 is disposed on the subject A side, and includes a convex surface 12a formed on the subject A side and a flat surface 12b facing the convex surface 12a. Here, for example, as shown in FIG. 2A, the convex lens 12 has a quadrangular shape when viewed from the subject A side. As shown in FIG. 2B, the convex lens 12 has a cross section along the line XX ′ (horizontal direction). As shown in FIG. 2C, the plano-convex lens has a convex shape in the YY ′ cross section (vertical direction).

  In the lens array 13, a radial type refractive index distribution lens (GRIN lens) 14 is two-dimensionally arranged so as to face the convex lens 12. In addition, the lens array 13 is formed so that, for example, the horizontal and vertical lengths thereof are the same as those of the convex lens 12. Here, in order to simplify the explanation, the lens array 13 includes six refractive index distribution lenses 14 in the horizontal direction and the vertical direction, respectively.

Each of the refractive index distribution lenses 14 is arranged such that one end surface 14a abuts on the flat surface 12b of the convex lens 12 and the other end surface 14b abuts on the imaging surface 15a of the image sensor 15 described later. Here, the refractive index distribution lens 14 is bonded to the flat surface 12b of the convex lens 12, and the other end surface 14b is bonded to the imaging surface 15a of the image sensor 15, for example, using UV adhesive. . Further, the refractive index distribution lens 14 is formed such that the length L in the optical axis direction is ¼ of the meandering period of incident light incident on the refractive index distribution lens 14.
The length L in the optical axis direction is the length from one end face 14a to the other end face 14b in the gradient index lens 14, as shown in FIGS. 2 (b) and 2 (c).

  Further, since the refractive index distribution lens 14 has a higher refractive index as it approaches the center of the optical axis, it has a lens effect that incident light meanders and forms an image on the other end face. This principle is described in 1964 by D.C. MARCUSE et al., And details thereof are described in “The Bell System Technical Journal. (July, 1964)” and the like.

Here, coupling magnification M _t by a convex lens 12 and the refractive index distribution lens 14, as represented by the following formula (1), the focal length f _r of the refractive index distribution lens 14, the object distance a ₁ It becomes a ratio.

M _t = −f _r / a ₁ Formula (1)
That is, in Expression (1), the focal length _fr is the length L of the gradient index lens 14 in the optical axis direction. The subject distance a ₁ is a distance from the principal point of the convex lens 12 to the subject A.

Therefore, the stereomicroscope device 1 can be designed flexibly because the coupling magnification M _t is not affected by the focal length f ₀ of the convex lens 12. In addition, the stereoscopic microscope apparatus 1 can perform imaging without being affected by scratches or dust on the convex lens 12.

  The imaging element 15 is a light receiving element such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) that captures an elemental image of the subject A formed on the other end face 14b of the gradient index lens 14. Further, the imaging element 15 is disposed so that the imaging surface (light receiving surface) 15 a for capturing the elemental image of the subject A is in contact with the other end surface 14 b of the gradient index lens 14 so as to face the lens array 13. . Then, the imaging device 15 outputs each of the captured element images of the subject A to the multi-viewpoint / stereoscopic image signal processing means 17 described later.

Further, for example, the imaging element 15 has the same horizontal and vertical lengths as the convex lens 12 and the lens array 13.
In addition, the image sensor 15 includes an element image block 16 so as to correspond to the gradient index lens 14 on a one-to-one basis, for example. The element image block 16 is composed of a large number of pixels (for example, several hundred or more). Here, in order to simplify the description, the imaging device 15 includes six element image blocks 16 in the horizontal direction and the vertical direction, respectively.

The multi-viewpoint / stereoscopic image signal processing means 17 performs signal processing for performing multi-viewpoint stereoscopic display on the element image input from the image sensor 15. For example, the multi-viewpoint / stereoscopic image signal processing means 17 generates a multi-viewpoint image (stereoscopic image of the subject A) in which the input element images are arranged vertically and horizontally, and the multi-viewpoint / stereoscopic image monitor 19 Output to.
In addition, the multi-viewpoint / stereoscopic image signal processing unit 17 outputs all input element images to the element image selection unit 18.

  The element image selection means 18 receives the element images of the subject A from the multi-viewpoint / stereoscopic image signal processing means 17 and selects two preset element images from the element images of the subject A. . Then, the element image selection means 18 outputs the selected two element images to the binocular stereoscopic image monitor 20 as a stereo image.

  Here, the user of the stereoscopic microscope device 1 visually observes the subject according to the size of the subject A, the distance from the subject A to the stereoscopic microscope device 1, and the size of the binocular stereoscopic image monitor 20, for example. It can be set in advance so that two element images that are easy to observe A are selected. There is no particular limitation on how to select two element images. For example, the two element images may be set in advance so as to select two element images that are located in the center in the vertical direction and that are farthest in the horizontal direction. . Further, for example, it may be set in advance so that two element images located obliquely to each other are selected.

The multi-viewpoint / stereoscopic image monitor 19 is a monitor that stereoscopically displays the multi-viewpoint image input from the multi-viewpoint / stereoscopic image signal processing means 17.
The binocular stereoscopic image monitor 20 is a monitor that stereoscopically displays two element images input from the element image selection means 18. Since the multi-viewpoint / stereoscopic image monitor 19 and the binocular stereoscopic image monitor 20 are the same as the conventional ones, detailed description thereof will be omitted.

<Photographing with a stereomicroscope>
Hereinafter, photographing in the stereoscopic microscope apparatus 1 will be described in detail. At this time, the subject A will be described as being located at the focal length f ₀ of the convex lens 12.

  The convex lens 12 emits incident light from the subject A to the refractive index distribution lens 14 as parallel light. The refractive index distribution lens 14 propagates the incident light of the subject A incident from the convex lens 12 while periodically meandering. Here, the refractive index distribution lens 14 functions as a convex lens because the length L in the optical axis direction is 1/4 of the meandering period of incident light from the subject A. That is, the gradient index lens 14 forms an element image of the subject A as an inverted image on the other end surface 14b (see symbol α in FIG. 1).

  Thereafter, the image sensor 15 captures an elemental image of the subject A formed on the other end surface 14 b of the gradient index lens 14. That is, in the stereoscopic microscope apparatus 1, the elemental image of the subject A is equivalent to that the subject A is converged and photographed from different directions. In other words, the stereoscopic microscope apparatus 1 can obtain multi-viewpoint three-dimensional information from the element image of the subject A because the element image of the subject A corresponds to the shooting direction and has parallax. A multi-viewpoint image (stereoscopic image of the subject A) can be generated.

<When the subject is located off the optical axis of the convex lens>
Here, consider a case where two or more subjects are located off the optical axis of the convex lens 12 (not shown). In this case, incident light from these subjects enters the convex lens 12 in a direction oblique to the subject with respect to the optical axis of the convex lens 12. In this case, it is considered that the light is incident not on the element image block 16 positioned on the optical axis with the gradient index lens 14 but on another element image block 16 adjacent thereto. However, since the stereoscopic microscope apparatus 1 includes the refractive index distribution lens 14 as an element lens of the lens array 13, incident light from a subject is prevented from entering another adjacent element image block 16. That is, the gradient index lens 14 functions as a kind of light shielding means. As a result, the stereoscopic microscope apparatus 1 does not cause a situation in which the element images of these subjects overlap in the image sensor 15 and the images of these subjects cannot be separated.

  As described above, the stereoscopic microscope apparatus 1 according to the first embodiment of the present invention is simple by simply sandwiching the lens array 13 between the convex lens 12 and the image sensor 15 without using a plurality of photographing cameras and light separation means. With this arrangement, the elemental image of the subject A can be taken. In addition, since the stereoscopic microscope apparatus 1 can shoot an elemental image of the subject A by itself, it does not require complicated adjustments such that a plurality of photographing cameras are directed toward the subject A, and the adjustment is easy. Furthermore, even when two or more subjects are located off the optical axis of the convex lens 12, the stereoscopic microscope apparatus 1 does not cause a problem that the images of these subjects cannot be separated. be able to.

  In the first embodiment of the present invention, the stereoscopic microscope apparatus 1 has been described as an example of the present invention, but it is needless to say that the present invention is not limited to this. For example, the present invention can be applied to an integral photography system or a binocular stereoscopic vision.

In the first embodiment of the present invention, the subject A is described as being located at the focal length f ₀ , but the present invention is not limited to this. That is, the stereoscopic microscope apparatus 1 can capture an elemental image of the subject A using the blur of the subject A when the subject A is located at a position other than the focal length f ₀ .

  In the first embodiment of the present invention, the refractive index distribution lens 14 and the element image block 16 are described as being provided in the horizontal direction and the vertical direction, respectively, but the present invention is not limited to this. For example, the stereoscopic microscope apparatus 1 may include different numbers in the horizontal direction and the vertical direction, the gradient index lens 14 and the element image block 16 (not shown). For example, when the present invention is applied to the integral photography system, the number of the gradient index lenses 14 and the element image blocks 16 is larger (thousands to tens of thousands).

  Although the convex lens 12 has been described as a plano-convex lens in the first embodiment of the present invention, other convex lenses may be used.

  In the first embodiment of the present invention, the stereoscopic microscope apparatus 1 includes a multi-viewpoint / stereoscopic image signal processing unit 17, an element image selection unit 18, a multi-viewpoint / stereoscopic image monitor 19, and a binocular stereoscopic image monitor. However, it is not necessary to provide all of them. For example, when the binocular stereoscopic display is not performed, the stereoscopic microscope apparatus 1 may not include the element image selecting unit 18 and the binocular stereoscopic image monitor 20. For example, when multi-view stereoscopic display is not performed, the stereoscopic microscope apparatus 1 outputs the element image of the subject A captured by the image sensor 15 to the element image selection unit 18, and multi-view / stereo image signal processing unit. 17 and the multi-viewpoint / stereoscopic image monitor 19 may not be provided.

(Second Embodiment)
With reference to FIG. 3, differences from the first embodiment will be described with respect to the configuration of the stereoscopic microscope apparatus 1 </ b> B according to the second embodiment of the present invention. In this stereoscopic microscope apparatus 1B, the length of the refractive index distribution lens 14B in the optical axis direction is different from that of the refractive index distribution lens 14 of FIG.

  As shown in FIG. 3, the stereoscopic microscope apparatus 1 </ b> B includes an image sensor drive circuit 11, a convex lens 12, a lens array 13 </ b> B, an image sensor 15, a multi-viewpoint / stereoscopic image signal processor 17, and an element image selector 18. A multi-viewpoint / stereoscopic image monitor 19 and a binocular stereoscopic image monitor 20.

  In FIG. 3, the incident light from the subject A is illustrated by a broken-line arrow. 3 is an element image of the subject A formed on the other end face 14b of the gradient index lens 14B. Further, in FIG. 3, in order to simplify the description, illustrations of partial configurations of the image sensor driving circuit 11 and the multi-viewpoint / stereoscopic image signal processing means 17 are omitted.

  In the lens array 13B, as in the first embodiment, the refractive index distribution lenses 14B are two-dimensionally arranged. Here, the refractive index distribution lens 14B is formed such that the length L in the optical axis direction is 3/4 of the meandering period of incident light incident on the refractive index distribution lens 14B. In this case, each of the refractive index distribution lenses 14B forms an elemental image of the subject A as an erect image on the other end surface 14b (see symbol β in FIG. 3).

Here, the sign of the coupling magnification M _t by the convex lens 12 and the gradient index lens 14B is opposite to that of the formula (1) as represented by the following formula (2).
M _t = f _r / a ₁ Formula (2)

  Each configuration other than the lens array 13B and the gradient index lens 14B is the same as that shown in FIG.

  As described above, the stereoscopic microscope apparatus 1B according to the second embodiment of the present invention has the same effects as the stereoscopic microscope apparatus 1 according to the first embodiment except that an erect image of the subject A can be obtained.

  In the first and second embodiments, the length in the optical axis direction of the gradient index lenses 14 and 14B has been described as 1/4 or 3/4 of the meandering period of incident light, but the present invention is not limited to this. For example, in the present invention, the length of the gradient index lens in the optical axis direction may be (2n−1) / 4 of the meandering period of incident light incident on the gradient index lens (where n is 1). Or an integer).

1,1B Stereoscopic microscope (stereoscopic imaging device)
DESCRIPTION OF SYMBOLS 11 Image pick-up element drive circuit 12 Convex lens 12a Convex surface 12b Flat surface 13, 13B Lens array 14, 14B Refractive index distribution lens 14a One end surface 14b The other end surface 15 Image pick-up element 15a Imaging surface 16 Element image block 17 Multi-viewpoint / stereoscopic image signal processing Means 18 Element image selection means 19 Multi-viewpoint / stereoscopic image monitor 20 Binocular stereoscopic image monitor

Claims (5)

One plano- convex lens arranged on the subject side, a lens array in which a refractive index distribution lens is arranged two-dimensionally facing the plano- convex lens, and an element image of the subject are photographed facing the lens array A three-dimensional image capturing device comprising an image sensor,
The plano- convex lens includes a convex surface formed on the subject side, and a flat surface facing the convex surface,
The lens array has the same horizontal and vertical length as the plano-convex lens,
The gradient index lens element, with one end surface is in contact with the flat surface of the plano-convex lens, wherein an incident light from the subject entering through the plano-convex lens, the end face of the other opposed to the one end face It is imaged as an element image of the subject,
The imaging device photographs an element image of the subject imaged on the other end surface of the refractive index distribution lens while a photographing surface for photographing the element image of the subject is in contact with the other end surface of the refractive index distribution lens. A three-dimensional image photographing device.   2. The three-dimensional object according to claim 1, wherein the refractive index distribution lens has a length in the optical axis direction of (2n−1) / 4 of a meandering period of incident light incident on the refractive index distribution lens. Image photographing device (where n is an integer of 1 or more).   3. The stereoscopic image photographing apparatus according to claim 2, wherein the refractive index distribution lens has a length in the optical axis direction that is ¼ of a meandering period of incident light incident on the refractive index distribution lens. .   The stereoscopic image capturing apparatus according to claim 2, wherein the refractive index distribution lens has a length in the optical axis direction that is 3/4 of a meandering period of incident light incident on the refractive index distribution lens. .   The element image selection means for selecting two preset element images from the element images of the subject imaged by the image sensor is further provided. Stereoscopic imaging device.

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