KR20140002848A - Device and method for generating hologram - Google Patents

Abstract

An embodiment of the present invention provides a hologram generating device including an optical field data generating part generating optical field data about a subject and a hologram generating part generating hologram data about the subject. The hologram generating part includes a depth surface setting part setting a plurality of different depth surfaces on which one or more light beams are collected based on the optical field data, a refocus image data generating part generating a plurality of refocus image data corresponding to the depth surfaces based on the optical field data, and an image arranging part generating the hologram data by using a stack arranging the refocus image data according to the depth surfaces. [Reference numerals] (111) First lens part; (112) Second lens part; (113) Photographing part; (121) Depth surface setting part; (122) Refocus image data generating part; (123) Image arranging part

Description

TECHNICAL FIELD [0001] The present invention relates to a device and a method for generating a hologram,

The present invention relates to an apparatus and method for generating a hologram, and more particularly, to an apparatus and a method for generating a hologram based on optical field data.

3D images are more realistic and naturally sensed than 2D images because they are expressed in close proximity to human realism. Accordingly, research and demand for 3D images are increasing.

Of these three-dimensional image related technologies, holography is a technique of recording all the information of light with waves, that is, amplitude and phase (phase), and a photographic film recorded by a holographic method or an image reproduced by the holographic method is called ' quot; hologram ".

The photographic technique, which is a two-dimensional image, records only the amount of change in intensity of light reflected from an object (subject). For example, dark areas with low reflected light and bright areas with high reflected light are recorded.

On the other hand, since holography records not only the intensity of light but also the phase of light as a wave, it reproduces a three-dimensional image. At this time, the phase of the light is recorded as a complex interference fringe which is generated by mutual interference between the object light reflected by the object illuminated by one light beam and the reference light which is another light beam reflected by the holographic photosensitive material.

However, the interference fringe is not formed by a white light source including various colors such as natural light or incandescent light, and is easily recorded only by using a laser which is a monochromatic light with good coherence.

1 is a view for explaining a holographic photographing method for recording a hologram.

As shown in Fig. 1, an interference optical system 10 is configured to photograph a hologram. The interference optical system includes a laser light source 11 for irradiating an interference light source, a beam splitter 12 for transmitting a part 12a of the interference light source in a first direction and reflecting the remaining part 12b in a second direction, And a mirror 13 for reflecting the light 12b in the direction toward the photosensitive material 20 side.

Here, the light 12a in the first direction is reflected by the object 30 to become the object light 10a, and the light 12b in the second direction is reflected by the mirror 13 to become the reference light 10b . The complex interference fringe generated by mutual interference between the object light 10a and the reference light 10b is recorded in the photosensitive material 20 as an intensity distribution including the phase information of the light.

In order to photograph the hologram, the hologram can not be easily photographed under ordinary external illumination due to the use of the interference light source. Therefore, it is necessary to perform the hologram in a dark room environment, and the complex interference fringe can be easily changed by the vibration, There is a problem that it can be performed only on the optical table.

Due to such a problem, shooting of the hologram can be performed only in a laboratory where environmental control is easy, and can not be easily performed in a general external environment.

On the other hand, as another holographic imaging method, there is a method of using a plurality of cameras instead of using an interference optical system. That is, the subject is photographed at different angles using a plurality of cameras, and the disparity between the generated images is analyzed to extract the depth information of the subject. Then, the hologram is synthesized by using the depth information . As described above, the holographic photographing method using a plurality of cameras has a problem in that it is difficult to easily use the cameras in daily life because a plurality of cameras must be operated collectively.

One embodiment of the present invention is to provide a hologram generating apparatus and method that can easily generate a hologram without using an interference light source or a plurality of cameras, and without creating a special environment.

According to an aspect of the present invention, there is provided an apparatus for generating holograms, comprising: an optical field data generator for generating optical field data on a subject; And a hologram generating unit for generating hologram data on the subject based on the one optical field data, wherein the hologram generating unit generates, based on the one optical field data, a plurality of different depths A depth surface setting unit for setting a surface; A refocusing image data generation unit that generates a plurality of refocused image data corresponding to the plurality of depth planes based on the one optical field data; And an image arrangement unit for generating the hologram data using a stack in which the plurality of refocused image data are arranged along the plurality of depth planes.

According to an embodiment of the present invention, there is provided a method of generating a hologram by a hologram generating apparatus, comprising: generating optical field data relating to a subject; Establishing a plurality of different depth planes based on the light field data, wherein the one or more rays gather; Generating a plurality of refocused image data corresponding to the plurality of depth planes based on the optical field data; And generating hologram data based on the plurality of refocused image data.

An apparatus and method for generating a hologram according to an embodiment of the present invention generate hologram data based on optical field data generated by first and second lens units. Thus, special environmental conditions for generating a hologram, that is, an interference light source and an optical table are unnecessary, and hologram data can be generated for a general illumination environment, that is, a subject in an external environment.

Also, since one optical field data includes two or more refocused image data corresponding to two or more different depth planes, it is possible to use a plurality of cameras set at different focal lengths, It is possible to generate the hologram data with one optical field data by the conference shooting.

Therefore, hologram data can be generated more easily and easily than before, and the user's convenience can be improved.

1 is a view for explaining a holographic photographing method for recording a hologram.
2 is a block diagram illustrating a hologram generating apparatus according to an embodiment of the present invention.
3 is a flowchart illustrating a method of generating a hologram according to an embodiment of the present invention.
FIG. 4 is an illustration for explaining that the hologram generating apparatus according to the embodiment of the present invention generates optical field data relating to a subject.
Fig. 5 is a diagram for explaining how the hologram generating apparatus sets a plurality of different depth planes with respect to an object in the example of Fig. 4. Fig.
Fig. 6 is a hologram data generated by the hologram generating device in the example of Fig. 4 and Fig.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "electrically connected" with another part in between . Also, when an element is referred to as "comprising ", it means that it can include other elements as well, without departing from the other elements unless specifically stated otherwise.

First, an apparatus and method for generating a hologram according to an embodiment of the present invention will be described with reference to FIGS. 2 and 3. FIG.

FIG. 2 is a block diagram illustrating a hologram generating apparatus according to an embodiment of the present invention, and FIG. 3 is a flowchart illustrating a method of generating a hologram according to an embodiment of the present invention.

2, the hologram generating apparatus 100 according to an embodiment of the present invention includes an optical field data generating unit 110 for generating optical field data on a subject, And a hologram generating unit 120 for generating a hologram on the basis of one optical field data.

The optical field data generation unit 110 includes a first lens unit 111, a second lens unit 112, and an image pickup unit 113.

The first lens unit 111 focuses the rays relating to the object. That is, the first lens unit 111 is a means for adjusting a focal length and an angle of view of an object to be photographed.

The second lens unit 112 includes a microlens array in which a plurality of microlenses are arranged in a matrix of NxM. The second lens unit 112 separates the light beams passing through the first lens unit 111 along the respective directions.

The imaging unit 113 includes a sensor array in which a plurality of photosensitive elements are arranged in an XxY matrix. This image capturing unit captures the light rays that have passed through the first and second lens units 111 and 112, and generates optical field data on the subject (not shown).

Here, since the light field data includes information on how much light has intensity in all directions in all points on the three-dimensional space, a light ray distribution according to directions and positions can be derived.

The hologram generating unit 120 includes a depth plane setting unit 121, a refocusing image data generating unit 122, and an image arranging unit 123.

The depth-plane setting unit 121 sets a plurality of different depth planes on which one or more rays converge, based on one optical field data.

As described above, since the light ray distribution by direction and position can be derived from the light field data, the depth plane setting unit 121 can derive a plurality of depth planes in which one or more rays are gathered. The plurality of depth planes may include at least one depth plane that is selected by the user or overlaps at least partially with the image of the predetermined object to be overlapped with the subject.

The refocusing image data generation unit 122 generates a plurality of refocused image data corresponding to the set plurality of depth planes based on one optical field data. That is, the refocusing image data generation unit 122 backs up light rays that converge on each depth surface in the optical field data, averages the backwardly traced light rays, and generates refocused image data corresponding to each depth surface do.

The image arrangement unit 123 generates hologram data on the object using a stack in which a plurality of refocused image data are arranged along a plurality of depth planes.

For example, the image arrangement unit 123 can generate hologram data based on the following Equation (1).

In Equation 1, H (u, v) is hologram data, and k DELTA z is any one of a plurality of depth planes, and I (x, y; k DELTA z) Is the corresponding refocused image data. H (x, y; kΔz) is a point spread funtion of the optical field data generating unit 110 for refocusing by one depth plane kΔz, and λ is The wavelength of the light, f is the focal length, and FT represents the Fourier Transform.

As shown in FIG. 3, a method of generating a hologram by the hologram generating apparatus 100 includes generating (S100) optical field data on a subject, generating a plurality of A step S110 of setting different depth planes, a step S120 of generating a plurality of refocus image data corresponding to a plurality of depth planes based on the optical field data, , And generating the hologram data (S130).

In step S100 of generating the optical field data, the optical field data is generated by the optical field data generation unit 110. [ That is, the light beams passing through the first lens unit 111 are separated in the respective directions by the second lens unit 112, and captured by the image pickup unit 113, thereby generating optical field data.

In step S110 of setting a plurality of different depth planes, a plurality of different depth planes, in which one or more rays gather, are derived based on the light field data. At this time, the plurality of depth planes are spaced apart from the optical field data generator 110 at different distances. At least one of the plurality of depth planes may be at least partially in contact with or overlapped with the image of the subject.

In a step of generating a plurality of refocused image data (S120), refocused image data corresponding to each depth surface is generated by tracing the rays gathered on each depth surface.

In the step of generating hologram data (S130), hologram data on a subject is generated using a stack in which a plurality of refocused image data are arranged along a plurality of depth planes. At this time, Equation 1 described above can be applied.

As described above, the apparatus and method for generating a hologram according to an embodiment of the present invention generate a hologram using optical field data. This eliminates the need for a special environment for constructing the interference optical system such as the coherent light source and the optical table, and it is unnecessary and inconvenient to control a large number of cameras. Therefore, the hologram can be generated more easily.

Next, referring to Figs. 4 to 6, examples of the apparatus and method for generating a hologram according to an embodiment of the present invention will be described in more detail.

FIG. 4 is an illustration for explaining that the hologram producing apparatus according to an embodiment of the present invention generates optical field data relating to a subject, and FIG. 5 is an example of FIG. FIG. 6 is a diagram for explaining setting of different depths, and FIG. 6 is hologram data generated by the hologram generating device in the example of FIGS.

4, in step S100 of generating the optical field data, the optical field data generation unit 110 generates optical field data on the object 200 in response to a control signal from the user .

In the optical field data generation unit 110, the first lens unit 111 may include at least one lens arranged in the direction in which the rays of light are incident.

The second lens unit 112 includes a microlens array made up of a plurality of microlenses arranged in a matrix of NxM on a plane perpendicular to the direction in which light enters.

The imaging section 113 includes a plurality of photosensitive elements arranged in an X-Y matrix on the surface of the second lens section 112 parallel to the microlens array.

As shown in FIG. 5, the depth setting unit 121 sets a plurality of different depth planes Z1, Z2, and Z3 in which one or more rays are gathered (S110).

At this time, the depth-plane setting unit 121 derives a plurality of different depth planes from which one or more rays gather from the optical field data. At this time, the plurality of extracted depth planes are spaced apart from the optical field data generation unit 110 by different distances. And, the plurality of depth planes may include at least one depth plane that is in contact with or overlaps with the image 201 of the subject and is associated with the subject.

For example, the plurality of depth planes may include a first depth plane Z1 spaced from the optical field data generation unit 110 by a first distance, a second depth plane Z1 spaced from the optical field data generation unit 110 by a second distance And a third depth surface Z3 that is spaced from the optical field data generator 110 by a third distance that is longer than the second distance.

The refocusing image data generation unit 122 generates a plurality of refocused image data corresponding to the plurality of depth planes set in step S110 based on one optical field data (S120). Here, the plurality of refocused image data correspond to a plurality of different depth planes.

6, the image arranging unit 123 extracts, based on Equation (1), hologram data relating to the object 200 from a stack in which a plurality of refocused image data are arranged along a plurality of depth planes (S130).

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

100: hologram generating device 110: optical field data generating unit
111: first lens unit 112: second lens unit
113: image pickup unit 120: hologram generating unit
121: depth setting unit 122: refocusing image data generating unit
123: image arrangement unit 200: subject
201: Top of the subject

Claims (9)

An apparatus for generating a hologram,
An optical field data generation unit generating optical field data relating to a subject; And
And a hologram generating unit for generating hologram data on the subject based on one optical field data by the optical field data generating unit,
The hologram-
A depth plane setting unit for setting a plurality of different depth planes in which one or more light rays are collected based on the one light field data;
A refocus image data generation unit configured to generate a plurality of refocus image data corresponding to the plurality of depth planes based on the one light field data; And
And an image arranging unit which generates the hologram data by using the stack in which the plurality of refocused image data are arranged along the plurality of depth planes. The method of claim 1,
Wherein the optical field data generator comprises:
A first lens unit focusing the rays;
A second lens unit including a microlens array, the second lens unit separating the light rays passing through the first lens unit according to respective directions; And
And an imaging unit that captures light rays that have passed through the first and second lens units and generates the optical field data. The method of claim 1,
Wherein the plurality of depth surfaces include at least one depth surface that is at least partially in contact with or overlapped with an image of the subject. The method of claim 1,
The image arrangement unit generates the hologram data based on the following equation (1)
(1)

In Equation 1, H (u, v) is hologram data, kΔz is any one of the plurality of depth planes, and I (x, y; kΔz) is any one of the depths. Refocus image data corresponding to a plane kΔz, wherein h (x, y; kΔz) is the light field data generation unit for the refocus of one of the depth planes kΔz. A point spread funtion, λ is the wavelength of the light beam, f is the focal length, and FT represents a Fourier Transform. A method of generating a hologram by a hologram generating device,
Generating optical field data relating to a subject;
Establishing a plurality of different depth planes based on the light field data, wherein the one or more rays gather;
Generating a plurality of refocused image data corresponding to the plurality of depth planes based on the optical field data; And
And generating hologram data based on the plurality of refocused image data. The method of claim 5, wherein
Wherein the step of generating the hologram data comprises:
And generating the hologram data using a stack in which the plurality of refocused image data are arranged along the plurality of depth planes. The method of claim 5, wherein
In the step of generating the optical field data,
Wherein the optical field data is generated by an optical field data generator,
The optical field data generation unit includes a first lens unit for focusing the light beams, a second lens unit including a microlens array and separating the light beams passing through the first lens unit along the respective directions, Wherein the light field data is generated by an imaging unit that captures the light beams and generates the light field data. The method of claim 5, wherein
In the step of setting the plurality of depth planes,
Wherein the plurality of depth surfaces include at least one depth surface that is at least partially in contact with or overlapped with an image of the subject. The method of claim 5, wherein
In the step of generating the hologram data,
Wherein the hologram data is generated based on the following equation (1)
(1)

In Equation 1, H (u, v) is hologram data, kΔz is any one of the plurality of depth planes, and I (x, y; kΔz) is any one of the depths. Refocus image data corresponding to a plane kΔz, wherein h (x, y; kΔz) is the light field data generation unit for the refocus of one of the depth planes kΔz. A point spread funtion, wherein λ is the wavelength of the light beam, f is the focal length, and FT represents a Fourier Transform.

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