KR20230072187A - Light field camera using optical fiber bundle - Google Patents

Abstract

The present invention relates to a light field camera that generates an image using an optical fiber bundle forming a curved surface. A light field camera using an optical fiber bundle according to an embodiment of the present invention is characterized in that it includes a micro lens array arranged along a curved surface and an optical fiber bundle positioned at a focal point of the micro lens array to collect light from a subject. .

Description

Light field camera using an optical fiber bundle {LIGHT FIELD CAMERA USING OPTICAL FIBER BUNDLE}

The present invention relates to a light field camera that generates an image using an optical fiber bundle forming a curved surface.

A light field camera is a camera that separates and senses the amount of light arriving from various directions in space, that is, a light field. To this end, the light field camera separates and senses the amount of light collected by the main lens according to the arrival direction of the light using a microlens array.

In such a light field camera, a main lens with a large curvature and size is used to sense a wide-angle image. In this case, distortion and curvature in the wide-angle due to structural limitations of the lens of image field) and increase the overall size of the camera.

In addition, the resolution of an image sensed in a conventional light field camera is determined by the number of micro lenses. Since there is a limit to the miniaturization of micro lenses, increasing the number of micro lenses increases the overall size of the camera.

An object of the present invention is to generate an image of a subject using an optical fiber bundle forming a curved surface.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention not mentioned above can be understood by the following description and will be more clearly understood by the examples of the present invention. It will also be readily apparent that the objects and advantages of the present invention may be realized by means of the instrumentalities and combinations indicated in the claims.

A light field camera using an optical fiber bundle according to an embodiment of the present invention for achieving the above object is a micro lens array arranged along a curved surface and an optical fiber bundle positioned at a focal point of the micro lens array to collect light from a subject. It is characterized in that it includes.

In one embodiment, a surface connecting the center of each lens constituting the micro lens array is a curved surface having a predetermined curvature.

In one embodiment, the micro lens array is characterized in that it is uniformly arranged in all directions based on the center of the curved surface.

In one embodiment, the optical fiber bundle is characterized in that it is composed of a plurality of unit bundles located at the focal point of each lens constituting the micro lens array.

In one embodiment, it is characterized in that the ends of the individual optical fibers constituting the optical fiber bundle are arranged along the focal plane of the micro lens array.

In one embodiment, it characterized in that it further comprises an image sensor for generating an image of the subject using the light collected from the optical fiber bundle.

In one embodiment, it is characterized in that each of the individual optical fibers constituting the optical fiber bundle is connected to the image sensor at a predetermined position to correspond to the coordinates of the image.

In one embodiment, the image sensor may generate an element image for each lens constituting the micro lens array, and generate an image of the subject by combining the element images.

In one embodiment, the image sensor is characterized in that it identifies the direction information of the light according to the displacement of the subject in the element image, and generates a refocused image of the subject based on the direction information of the light.

In one embodiment, a cylinder including the optical fiber bundle therein and having a diameter increasing with height, a light incident curved surface provided on an upper surface of the cylinder, on which the micro lens array is arranged, and a lower surface of the cylinder It is characterized in that it further comprises an image sensor for generating an image of the subject by using the light collected from the optical fiber bundle is coupled.

In one embodiment, images formed through adjacent lenses among a plurality of lenses included in the micro lens array are characterized in that they overlap each other.

In one embodiment, the images formed through the adjacent lenses are characterized in that they overlap each other by half or more.

By generating an image using an optical fiber bundle forming a curved surface, the present invention can innovatively reduce the size of a camera and solve problems of distortion and curvature of image field in a wide angle. .

In addition to the effects described above, specific effects of the present invention will be described together while explaining specific details for carrying out the present invention.

1 is a view showing a light field camera using an optical fiber bundle according to an embodiment of the present invention.
FIG. 2 is a diagram for explaining the micro lens array and the optical fiber bundle shown in FIG. 1;
3a and 3b are diagrams illustrating a micro lens array according to each embodiment of the present invention.
Fig. 4 is a diagram for explaining the positional relationship between a microlens and a unit bundle;
5 is a diagram illustrating how an image sensor generates an image of a subject;
6 is a view showing how an image sensor generates an image of a wide-angle subject;
7 is a view showing images formed through adjacent microlenses overlapping each other;

The above objects, features and advantages will be described later in detail with reference to the accompanying drawings, and accordingly, those skilled in the art to which the present invention belongs will be able to easily implement the technical spirit of the present invention. In describing the present invention, if it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

In this specification, first, second, etc. are used to describe various components, but these components are not limited by these terms, of course. These terms are only used to distinguish one component from another component, and unless otherwise stated, the first component may be the second component, of course.

In addition, in the present specification, "upper (or lower)" or "upper (or lower)" of a component means that an arbitrary component is disposed in contact with the upper (or lower) surface of the component. In addition, it may mean that other components may be interposed between the component and any component disposed on (or under) the component.

In addition, in the present specification, when a component is described as being “connected”, “coupled” or “connected” to another component, the components may be directly connected or connected to each other, but other components may be present between each component. It should be understood that elements may be “interposed,” or that each element may be “connected,” “coupled,” or “connected” through other elements.

Also, singular expressions used in this specification include plural expressions unless the context clearly indicates otherwise. In this application, terms such as "consisting of" or "comprising" should not be construed as necessarily including all of the various components or steps described in the specification, and some of the components or some of the steps It should be construed that it may not be included, or may further include additional components or steps.

In addition, in this specification, when "A and / or B", unless otherwise specified, it means A, B or A and B, and when "C to D", it means a special opposite Unless otherwise specified, it means more than C and less than D

The present invention relates to a light field camera that generates an image using an optical fiber bundle forming a curved surface. Hereinafter, a light field camera using an optical fiber bundle according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 7 .

1 is a diagram illustrating a light field camera using an optical fiber bundle according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining the micro-lens array and the optical fiber bundle shown in FIG. 1, and FIGS. 3A and 3B are diagrams illustrating the micro-lens array according to each embodiment of the present invention.

4 is a diagram for explaining the positional relationship between a microlens and a unit bundle.

FIG. 5 is a diagram illustrating how an image sensor generates an image of a subject, and FIG. 6 is a diagram illustrating how the image sensor generates an image of a wide-angle subject.

7 is a diagram illustrating a state in which images formed through adjacent microlenses overlap each other.

Referring to FIG. 1, a light field camera (100, hereinafter referred to as a light field camera) using an optical fiber bundle 120 according to an embodiment of the present invention functionally includes a micro lens array 110, an optical fiber bundle 120, and an image sensor. 130, and may structurally include a light incident curved surface 140 and a cylinder 150. However, the light field camera 100 shown in FIG. 1 is according to an embodiment, and its components are not limited to the embodiment shown in FIG. 1, and some components may be added, changed, or deleted as necessary. can

Referring to FIG. 2, the light field camera 100 of the present invention can generate an image of a subject 200 through a lens 111 that simulates the compound eye structure of an insect, and the light field camera 100 incident through the lens 111 Light may be collected through the fiber optic bundle 120 .

Hereinafter, each component of the invention for performing the above-described operation will be described in detail, and the micro lens 111 to be described later may be simply described as the lens 111.

The micro lens array 110 may be arranged along a curved surface. In other words, the micro lens array 110 includes a plurality of micro lenses 111, and the plurality of micro lenses 111 may be arranged side by side along a curved surface.

Referring to FIG. 3A , the light incident surface of each of the plurality of micro lenses 111 constituting the micro lens array 110 may form a curved surface as a whole. Since the surface of each of the micro lenses 111 is also a curved surface, the surface of the micro array does not form a precise curved surface, but a surface connecting the center of each micro lens 111 may be a curved surface having a certain curvature.

Also, referring to FIG. 3B , the micro lens 111 may be formed on the light incident curved surface 140 having a certain curvature. More specifically, the plurality of micro lenses 111 may be integrally formed on the light incident curved surface 140 instead of being individually designed as shown in FIG. 3A . To this end, the light incident curved surface 140 may have a shape in which a plurality of micro lenses 111 are patterned.

Such micro-lens arrays 110 may be uniformly arranged in all directions based on the center of the curved surface. Specifically, as shown in FIGS. 3A and 3B , the micro lenses 111 may be uniformly arranged in all directions based on the center C of the curved surface on which the micro lens arrays 110 are arranged.

As described above, since the micro lens array 110 is uniformly arranged in all directions along a curved surface, light can be collected in a wide range, so that the image sensor 130 to be described later generates an image of a wide-angle subject 200. make it possible

The optical fiber bundle 120 may be positioned at the focal point of the micro lens array 110 to collect light from the subject 200 . That is, the optical fiber bundle 120 may collect light condensed by each micro lens 111 by being positioned at the focal point of the micro lens array 110 .

Referring again to FIG. 2 in detail, the optical fiber bundle 120 may include a plurality of unit bundles 121 corresponding to each micro lens 111 . Specifically, when n lenses 111 form a microarray, the optical fiber bundle 120 may include n unit bundles 121 corresponding to each lens 111, and the unit bundle 121 The number of constituting individual optical fibers can be freely changed according to design needs.

At this time, each unit bundle 121 may be located at a focal point of an individual lens 111 constituting the micro lens array 110 . For example, when the n-th lens 111 and the n-th unit bundle 121 correspond to each other, the n-th unit bundle 121 is located at the focal point of the n-th lens 111, so that the n-th lens 111 Through the condensed light can be collected.

More specifically, the ends of individual optical fibers constituting the optical fiber bundle 120 may be arranged along the focal plane of the micro lens array 110 .

Hereinafter, the arrangement of the optical fiber bundle 120 will be described in detail with reference to FIG.

Referring to FIG. 4 , each micro lens 111 may have a two-dimensional focal plane. At this time, the ends of the unit bundles 121 corresponding to each micro lens 111, in detail, the ends of individual optical fibers constituting the unit bundles 121 may be arranged along a two-dimensional focal plane. In FIG. 4, only the ends of the optical fibers are arranged in the vertical direction along the focal plane for convenience of description, but the ends of the optical fibers may be arranged throughout the two-dimensional focal plane.

According to this arrangement, the light condensed through each microlens 111 can be incident to the end of the optical fiber arranged on the focal plane, and the incident light is totally reflected on the inner surface of the optical fiber, resulting in an image described later. It may be provided to the sensor 130.

Referring back to FIG. 1 , the above-described optical fiber bundle 120 may be included inside a cylindrical column 150 having a tapered structure, the diameter of which increases with height. As shown in FIG. 3B , when the micro lens array 110 is arranged on the light incident curved surface 140, the corresponding light incident curved surface 140 may be coupled to the upper surface of the cylinder 150. For this purpose, the light incident curved surface 140 ) may be the same as the diameter of the upper surface of the cylinder 150. At this time, the optical fiber bundle 120 within the cylinder 150 may be disposed at the focal point of each lens 111 to receive the light condensed by each micro lens 111 .

On the other hand, the image sensor 130 is implemented as a flat printed circuit board (PCB) and can be coupled to the lower surface of the cylinder 150, and the subject 200 is captured by using light collected from the optical fiber bundle 120. ) can generate an image of

To this end, the image sensor 130 may contact and/or be connected to one end of the optical fiber bundle 120 . That is, as described above, one end of the optical fiber bundle 120 may be arranged along the focal plane of the micro lens array 110, and the other end of the optical fiber bundle 120 may contact and/or be connected to the image sensor 130. can

Due to this physical structure, the wide-angle curved image generated through the micro lens array 110 may be projected onto the flat image sensor 130 as it is without distortion.

Meanwhile, the image sensor 130 may include application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), and field programmable circuits (FPGAs) in order to perform an image generating operation. gate arrays), controllers, micro-controllers, processors, and microprocessors.

Meanwhile, in order to reduce the processing load of the image sensor 130, each individual optical fiber constituting the optical fiber bundle 120 may be connected to the image sensor 130 at a predetermined position corresponding to the coordinates of the image of the subject 200. .

In other words, in order to reduce the load that the image sensor 130 maps the light collected through the individual fiber bundles 120 to specific coordinates of the image through post-processing, each fiber optic image sensor ( 130) may follow the coordinates of the image.

For example, in FIGS. 3A and 3B , the light collected through the optical fiber positioned at the center C of the curved surface corresponds to the coordinates of the center of the image, so that it may be contacted at the center of the image sensor 130 . Similarly, each of the optical fibers may be connected at each position of the image sensor 130 to correspond to the coordinates of an image to be generated according to the position on the cross section.

The image sensor 130 may generate an image of the subject 200 based on the intensity of light collected from individual optical fibers constituting the optical fiber bundle 120 . More specifically, the image sensor 130 may generate an elemental image for each lens 111 constituting the micro lens array 110 and generate an image of the subject 200 by combining the elemental images. there is.

Referring to FIG. 5 , the image sensor 130 may generate an element image for each lens 111 by summing the intensities of light collected through the unit bundle 121 corresponding to each micro lens 111, and synthesizing them. can be combined to create a single image. The image sensor 130 of the present invention may apply various methods used in the art to synthesize element images.

As described above, since one optical fiber corresponds to one pixel in an image in the present invention, the resolution of an image can be determined by the number of optical fibers. Accordingly, according to the present invention, a wide-angle image can be generated without distortion through the curved micro-lens array 110 and high resolution can be implemented by controlling the number of optical fibers.

In other words, referring to FIG. 6, the light field camera 100 of the present invention receives light from a wide-angle subject 200 through the micro lens array 110, and the received light is imaged through individual optical fibers. Provided to the sensor 130, the image sensor 130 may generate an image having a resolution corresponding to the number of optical fibers.

At this time, the wide-angle curved image is projected onto the image sensor 130 as a plane without distortion through the curved structure of the micro lens array 110 and the arrangement of the optical fibers, so that the wide-angle image is generated while the curvature of the image field) can be solved.

In addition, since the present invention generates an image by receiving light through the optical fiber bundle 120, the optical fiber can perform the role of a micro lens used in an existing light field camera, thereby reducing the size of the camera innovatively. there is.

Meanwhile, the image sensor 130 may identify light direction information according to the displacement of the subject 200 in the element image, and generate a refocused image of the subject 200 based on the light direction information.

Light intensity and light direction information may be required to generate an image of the refocused subject 200 . The image sensor 130 may use the displacement of the subject 200 in the element image to identify direction information of light.

Referring back to FIG. 5 , the image sensor 130 may identify a displacement of the subject 200 expressed in an element image adjacent to a positional contrast of the subject 200 expressed in a reference element image, that is, a central element image. can The image sensor 130 may identify direction information of light, that is, information about in which direction light from the subject 200 is incident, based on the identified displacement.

The image sensor 130 may generate an image of the subject 200 at the virtual focal point of the micro lens array 110 using light intensity and light direction information. To this end, various methods applied to conventional light field cameras, such as a trigonometric ratio method, may be utilized.

Meanwhile, the image sensor 130 may identify depth information of the subject 200 using light direction information. More specifically, the image sensor 130 may identify a disparity of an image generated by each micro lens 111 and use this to identify depth information of the subject 200 .

To this end, images formed through adjacent lenses 111 among the plurality of lenses 111 included in the micro lens array 110 may overlap each other.

Referring to FIG. 7 , assuming that first to fourth lenses are arranged adjacently in order, a first element image generated using light collected by the first lens and light collected by the second lens are The second element images generated using the image may be overlapped with each other.

Similarly, the second element image and the third element image generated using the light collected by the third lens overlap each other, and the third element image and the fourth element image generated using the light collected by the fourth lens. may overlap each other.

At this time, the overlapping ratio of adjacent element images may be preferably half or more. That is, it may be preferable that the first and second element images, the second and third element images, and the third and fourth element images overlap each other by half or more.

As described above, the present invention has been described with reference to the drawings illustrated, but the present invention is not limited by the embodiments and drawings disclosed in this specification, and various modifications are made by those skilled in the art within the scope of the technical idea of the present invention. It is obvious that variations can be made. In addition, although the operational effects according to the configuration of the present invention have not been explicitly described and described while describing the embodiments of the present invention, it is natural that the effects predictable by the corresponding configuration should also be recognized.

Claims (12)

a micro lens array arranged along a curved surface; and
An optical fiber bundle located at the focal point of the micro lens array to collect light from the subject
A light field camera using fiber optic bundles.
According to claim 1,
A surface connecting the center of each lens constituting the micro lens array is a curved surface having a certain curvature.
A light field camera using fiber optic bundles.
According to claim 1,
The micro lens array is uniformly arranged in all directions based on the center of the curved surface.
A light field camera using fiber optic bundles.
According to claim 1,
The optical fiber bundle is composed of a plurality of unit bundles located at the focal point of each lens constituting the micro lens array.
A light field camera using fiber optic bundles.
According to claim 1,
Ends of the individual optical fibers constituting the optical fiber bundle are arranged along the focal plane of the micro lens array.
A light field camera using fiber optic bundles.
According to claim 1,
Further comprising an image sensor for generating an image of the subject using the light collected from the optical fiber bundle
A light field camera using fiber optic bundles.
According to claim 6,
Each of the individual optical fibers constituting the optical fiber bundle is connected to the image sensor at a predetermined position corresponding to the coordinates of the image.
A light field camera using fiber optic bundles.
According to claim 6,
The image sensor generates element images for each lens constituting the micro lens array, and generates an image of the subject by combining the element images.
A light field camera using fiber optic bundles.
According to claim 8,
The image sensor identifies the direction information of light according to the displacement of the subject in the element image, and generates an image of the subject refocused based on the direction information of the light
A light field camera using fiber optic bundles.
According to claim 1,
A cylinder including the optical fiber bundle therein and having a diameter increasing with height;
a curved surface on which the microlens array is arranged and provided on an upper surface of the cylinder;
Further comprising an image sensor coupled to the lower surface of the cylinder and generating an image of the subject using light collected from an optical fiber bundle
A light field camera using fiber optic bundles.
According to claim 1,
Images formed through adjacent lenses among a plurality of lenses included in the micro lens array overlap each other.
A light field camera using fiber optic bundles.
According to claim 11,
The images formed through the adjacent lenses overlap each other by more than half.
A light field camera using fiber optic bundles.

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