KR101218151B1 - Method for generating fourier hologram of 3d object using multiple orthographic view image and optical apparatus for loading the fourier hologram - Google Patents

Abstract

Photographing an object from all directions to generate a plurality of 2D images, converting the generated 2D image into one 3D image, and each point O (x, y, z) of the object on the converted 3D image Is calculated by converting to the point P _{s , t} (x _p , y _p ) projected on the orthogonal projection plane _, and the phase term B _{s , t} (x _p ) from each point O (x, y, z) of the object. , y _p ), and multiplying the calculated P _{s , t} (x _p , y _p ) and the calculated B _{s , t} (x _p , y _p ) and multiplying the calculated values by x _p and y _p Double integration for each to calculate the Fourier hologram H (s, t). As described above, by generating and reproducing holograms based on parallel projection or orthographic projection, there is no limitation on the reproduction distance or angle. Thus, there is an effect that the reproduction distance can be arbitrarily changed or the image can be rotated or reversed. In addition, by generating the hologram according to the computer generated hologram (CGH) method, the problem of the optical method that requires long exposure to the minute vibration of the optical system or the recording medium is eliminated. On the other hand, by generating a hologram using a 3D image rather than a 2D image, there is an effect that can generate a hologram having a three-dimensional effect for the front of the object as well as the front of the object.

Description

FIELD OF GENERATING FOURIER HOLOGRAM OF 3D OBJECT USING MULTIPLE ORTHOGRAPHIC VIEW IMAGE AND OPTICAL APPARATUS FOR LOADING THE FOURIER HOLOGRAM}

The present invention relates to a hologram generating method and an optical reproducing apparatus, and more particularly, to a Fourier hologram generating method of a three-dimensional object using a multi-orthogonal projection image, and an optical reproducing apparatus.

The conventional hologram is a three-dimensional image using coherence by two laser lights, and may be regarded as being composed of amplitude information and phase information of reflected light of a subject recorded on a recording medium. Since the conventional hologram generation method uses an optical system, the interference fringes can be destroyed even with a small vibration, and thus, the hologram generation method needs to be very stable and precise. In addition, there is a problem in that it is developed by being exposed to a film, which is a recording medium, for a long time.

On the other hand, since the conventional holography method is based on perspective projection or perspective projection, vanishing point occurs. Thus, there is a problem that a restriction occurs in the reproduction distance or angle. For this reason, a formal approximation is required.

An object of the present invention is to provide a Fourier hologram generation method of a three-dimensional object using multiple orthogonal projection images.

Another object of the present invention is to provide an optical reproduction apparatus of a Fourier hologram of a three-dimensional object using multiple orthogonal projection images.

,

, 상기 수학식에 따라 상기 P_{s ,t}(x_p, y_p)를 산출하고, 여기에서, 상기 θ_x는 x축 투영 각도이고, 상기 θ_y는 y축 투영 각도이고, 상기 ㅣ은 고정 거리이다. 한편, 상기 물체의 각 점 O(x,y,z)으로부터 위상항 B_{s ,t}(x_p, y_p)를 산출하는 단계는, [수학식]

, 상기 수학식에 따라 상기 위상항 B_{s ,t}(x_p, y_p)를 산출하고, 여기에서, b =

이다. 그리고 상기 θ_x 및 θ_y는, 각각 - 5° 내지 + 5°의 범위 내인 것이 바람직하다.Fourier hologram generation method of a three-dimensional object using a multi-orthogonal projection image according to the object of the present invention, generating a plurality of 2D images by photographing the object from all directions, and the generated 2D image as a single 3D image And converting each point O (x, y, z) of the object on the converted 3D image into a point P _{s, t} (x _p , y _p ) projected on an orthogonal projection surface. Calculating a phase term B _{s , t} (x _p , y _p ) from each point O (x, y, z) of the object, the calculated P _{s , t} (x _p , y _p ) and the And multiplying the calculated B _{s , t} (x _p , y _p ) and double-integrating the multiplied values with respect to the x _p and y _p to calculate the Fourier hologram H (s, t). Here, the step of calculating and converting each point O (x, y, z) of the object on the converted 3D image into a point P _{s, t} (x _p , y _p ) projected on an orthogonal projection plane is [math] expression]

,

, P _{s , t} (x _p , y _p ) is calculated according to the equation, wherein θ _x is the x-axis projection angle, θ _y is the y-axis projection angle, and | to be. On the other hand, the step of calculating the phase term B _{s , t} (x _p , y _p ) from each point O (x, y, z) of the object,

, Calculating the phase term B _{s , t} (x _p , y _p ) according to the above equation, wherein b =

to be. And it is preferable that the said (theta) _x and (theta) _y exist in the range of -5 degrees-+5 degrees, respectively.

, 상기 수학식에 따라 푸리에 홀로그램 H(s, t)를 합성하고, 여기에서, 상기 P_{s ,t}(x_p, y_p)는 상기 3D 영상 상의 물체의 한 점 O(x, y, z)로부터 직교 투영면 상에 투영된 점으로서 하기 수학식에 따라 산출되고, [수학식]

,

, 여기에서, 상기 θ_x는 x축 투영 각도이고, 상기 θ_y는 y축 투영 각도이고, 상기 l은 고정 거리이고, 상기 B_{s ,t}(x_p, y_p)는 위상항으로서 하기 수학식에 따라 산출되고, [수학식]

, 여기에서,

이다. 그리고 상기 CCD 제어부는, 상기 CCD부의 위치를 변경하여 상기 푸리에 홀로그램의 재생 거리 및 회전을 임의로 제어하도록 구성될 수 있다. 그리고 상기 레이저 광원부는, 405 nm, 532 nm 또는 633 nm의 파장을 갖는 레이저 광을 방사하도록 구성될 수 있다.According to another aspect of the present invention, an optical reproducing apparatus of a Fourier hologram of a three-dimensional object using a multi-orthogonal projection image includes a laser light source for emitting laser light, and a plane wave by transmitting the emitted laser light. A first lens portion to be formed, a mirror portion to reflect the formed plane wave, a spatial light modulator (SLM) portion to receive and radiate the reflected plane wave, and a Fourier hologram from a 3D image And a hologram synthesizing portion for forming a synthesized Fourier hologram on the SLM portion, a second lens portion for transmitting a plane wave emitted through the SLM portion to form a predetermined focal length, and a distance between the second lens portion. The CCD may be configured to include a charge coupled device (CCD) unit configured to form an image, and a CCD controller configured to display the formed image on a display. Here, the hologram synthesis unit, [mathematical formula]

, Synthesize the Fourier hologram H (s, t) according to the equation, wherein P _{s , t} (x _p , y _p ) is a point O (x, y, z) of the object on the 3D image It is calculated according to the following formula as a point projected on the orthogonal projection surface from

,

, Wherein θ _x is the x-axis projection angle, θ _y is the y-axis projection angle, l is a fixed distance, and B _{s , t} (x _p , y _p ) is a phase term Calculated according to [Equation]

, From here,

to be. The CCD control unit may be configured to arbitrarily control the reproduction distance and rotation of the Fourier hologram by changing the position of the CCD unit. The laser light source unit may be configured to emit laser light having a wavelength of 405 nm, 532 nm, or 633 nm.

According to the Fourier hologram generation method of a three-dimensional object using the multi-orthogonal projection image as described above, by limiting the reproduction distance or the angle by generating and reproducing the hologram based on a parallel projection or an orthographic projection, Disappear. Thus, there is an effect that the reproduction distance can be arbitrarily changed or the image can be rotated or reversed. In addition, by generating the hologram according to the computer generated hologram (CGH) method, the problem of the optical method that requires long exposure to the minute vibration of the optical system or the recording medium is eliminated. In addition, the hologram can be generated and reproduced for two overlapping objects.

On the other hand, by generating a hologram using a 3D image rather than a 2D image, there is an effect that can generate a hologram having a three-dimensional effect for the front of the object as well as the front of the object.

1A is a conceptual diagram of an orthogonal projection, and FIG. 1B is a conceptual diagram of a perspective projection.
2 is a structural diagram of an orthographic projection coordinate system according to an embodiment of the present invention.
3 is a flowchart of a method for generating a Fourier hologram of a 3D object using multiple orthogonal projection images according to an exemplary embodiment of the present invention.
4A is the magnitude of the Fourier holograms of two objects at different distances, and FIG. 4B is the phase of the Fourier hologram.
FIG. 5A is a reproduced image of an object at an actual distance of 550 mm according to an embodiment of the present invention, and FIG. 5B is a reproduced image of an object at an actual distance of 650 mm.
FIG. 6A is a reproduced image of an object at an inverted distance of 200 mm, and FIG. 6B is a reproduced image of an object at an inverted distance of 300 mm according to an embodiment of the present invention.
FIG. 7A is a reproduction image of an object at a rotated distance of 200 mm, and FIG. 7B is a reproduction image of an object at a rotated distance of 300 mm. Referring to FIG.
8 is a block diagram illustrating an optical reproducing apparatus of a Fourier hologram of a 3D object using multiple orthogonal projection images according to an exemplary embodiment.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing.

The terms first, second, A, B, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

1A is an orthographic projection and FIG. 1B is a conceptual diagram of perspective projection.

Fourier hologram generation and reproduction method of a three-dimensional object using a multi-orthogonal projection image according to the present invention is a computer generated hologram based on a parallel or orthographic projection method shown in FIG. ). Conventionally, as shown in FIG. 1B, a perspective or perspective projection method is used, and thus, vanishing points or vanishing planes exist. Thus, there was a limit on the distance over which images could be formed. However, in the present invention, since a hologram formed from one laser light at an infinite distance is generated by computer simulation, there is no vanishing point or vanishing surface. Therefore, there is an advantage that there is no restriction on the reproduction distance during reproduction. In addition, it is a matter of course that there is no need for a sophisticated optical configuration or recording medium.

Meanwhile, the Fourier hologram generation and reproduction method of a three-dimensional object using a multi-orthogonal projection image according to the present invention synthesizes a plurality of 2D images taken from all directions of the object into a 3D image, and then generates a computer-generated hologram based on this. . Thus, although a stereoscopic image can be generated only on one side of an object, the present invention has a feature of generating and playing a hologram in front of an object.

2 is a structural diagram of an orthographic projection coordinate system according to an embodiment of the present invention.

Referring to FIG. 2, each point O (x, y, z) of an object in an image is projected onto a projection plane on the x axis and the y axis. In this case, the z axis may be an axis representing a distance between the object and the projection surface.

On the other hand, P _{s , t} (x _p , y _p ) represents each point where each point O (x, y, z) of the object is projected on the projection surface. Here, s and t correspond to each pixel coordinate on the x and y axes. The following description will be made based on such an orthogonal projection coordinate system.

3 is a flowchart of a method for generating a Fourier hologram of a 3D object using multiple orthogonal projection images according to an exemplary embodiment of the present invention. Detailed steps will be described below.

First, a plurality of 2D images are generated for an object in all directions of the object (S110). In this case, it is preferable to generate a plurality of 2D images of the object by using a plurality of microlens arrays arranged at regular intervals.

Next, the plurality of previously generated 2D images are converted into one 3D image (S120). In this way, by compositing one 3D image, it is possible to generate a hologram for the front of the object.

Next, each point O (x, y, z) of the object on the 3D image converted before is converted into a point P _{s , t} (x _p , y _p ) projected on the orthogonal projection surface and calculated (S130). Here, P _{s , t} (x _p , y _p ) may be calculated from Equation 1 below.

Here, θ _x is the x-axis projection angle, θ _y is the y-axis projection angle, and | At this time, θ _x and θ _y may be configured to be adjustable within the range of −5 ° to + 5 °, respectively.

If the fixed distance l is 5 meters and the projection angles θ _x and θ _y are -5 ° to + 5 °, respectively, then the hologram of 87 X 87 pixels is divided by 87 intervals between the minimum and maximum projection angles. Can be generated. That is, the pixel size of the hologram is related to the number of multiple orthogonal projection images.

Next, a phase term B _{s , t} (x _p , y _p ) is calculated from each point O (x, y, z) of the object (S140). In this case, B _{s , t} (x _p , y _p ) may be calculated from Equation 2 below.

이다.From here,

to be.

Next, multiply the previously calculated P _{s , t} (x _p , y _p ) and B _{s , t} (x _p , y _p ) and double-integrate the multiplied values for x _p and y _p , respectively, to determine the Fourier hologram H (s , t) is calculated (S150). Mathematically, it is expressed as Equation 3 below.

Equation 3 is a Fourier hologram H (s, t) is to multiply each pixel is P _{s , t} (x _p , y _p ) and the phase term B _{s , t} (x _p , y _p ), each point of the orthogonal projection surface As an integral, s matches the number of horizontal pixels in the hologram, and t matches the number of vertical pixels in the hologram. This also means that the total number of holographic pixels is equal to the total number of multiple orthogonal projection images.

As described above, the calculation may be implemented through a program that is pre-implemented on a computer. As such, the Fourier hologram generation method is implemented on a computer, which does not require a reference light and generates accurate Fourier holograms without requiring coherence.

On the other hand, the simulated Fourier hologram can be played on a computer as it is. The method for reproducing a Fourier hologram according to an embodiment of the present invention may be configured to simulate the Fourier hologram H (s, t) on a computer according to Equation 4 below.

이고,

이다. 이때, z₁ 및 z₂는 서로 다른 물체의 거리, f는 초점 거리, d₁ 및 d₂는 서로 다른 물체의 재생 거리이다.From here,

ego,

to be. In this case, z ₁ and z ₂ are distances of different objects, f is focal length, and d ₁ and d ₂ are reproduction distances of different objects.

Since this Fourier hologram is based on the parallel projection method, it can be reproduced at any reproduction distance d as mentioned above.

4A is the magnitude of the Fourier holograms of two objects at different distances, and FIG. 4B is the phase of the Fourier hologram.

4A and 4B, the magnitude and phase values of the Fourier holograms of two objects at different distances are captured, respectively. The images of the Fourier holograms of the two objects according to actual distances and rotation angles are shown in FIGS. 5A to 7B.

FIG. 5A is a reproduced image of an object at an actual distance of 550 mm according to an embodiment of the present invention, and FIG. 5B is a reproduced image of an object at an actual distance of 650 mm. FIG. 6A is a reproduction image of an object at an inverted distance of 200 mm, and FIG. 6B is a reproduction image of an object at an inverted distance of 300 mm according to an embodiment of the present invention. 7A is a playback image of an object at a rotated distance of 200 mm, and FIG. 7B is a playback image of an object at a rotated distance of 300 mm.

As such, the Fourier hologram according to the present invention can accurately reproduce objects at different distances, and can freely control the rotation angle. In addition, even when two objects overlap, each can be reproduced accurately.

8 is a block diagram illustrating an optical reproducing apparatus of a Fourier hologram of a 3D object using multiple orthogonal projection images according to an exemplary embodiment.

Referring to FIG. 8, an optical reproducing apparatus 100 (hereinafter, referred to as an “optical reproducing apparatus”) of a Fourier hologram of a 3D object using a multi-orthogonal projection image according to an exemplary embodiment may include a light source unit 110, First lens unit 120, mirror unit 130, SLM unit 140 (spatial light modulator), hologram synthesizing unit 150, second lens unit 160, CCD unit 170 and CCD control unit 180 It can be configured to include).

The optical reproducing apparatus 100 is an apparatus for optically reproducing H (s, t), which is a computer-generated hologram, and is configured to arbitrarily adjust the reproduction distance at which an image is formed. At this time, it is configured to be projected by a plane wave (plane wave). Hereinafter, the detailed configuration will be described.

The laser light source unit 110 emits laser light. Here, the laser light source unit 110 may be configured to emit laser light having a wavelength of 405 nm, 532 nm or 633 nm. Conventionally, only a light source of 532 nm is used, but in the present invention, laser light sources of various wavelengths may be used.

The first lens unit 120 transmits the laser light emitted from the laser light source unit 110 to form a plane wave. Conventional optical holography systems mainly use laser light according to perspective projection, but in the present invention, plane waves according to parallel projection are required.

The mirror unit 130 reflects the plane wave formed by the first lens unit 120.

The SLM unit 140 receives and radiates the plane wave reflected by the mirror unit 130. The SLM unit 140 may be configured to use only the amplitude of the hologram.

The hologram synthesis unit 150 synthesizes a Fourier hologram from the 3D image and forms the synthesized Fourier hologram on the SLM unit 140. The hologram synthesizing unit 150 may be configured to synthesize the Fourier holograms H (s, t) according to Equation 5 below.

Here, P _{s , t} (x _p , y _p ) is a point projected on an orthogonal projection surface from one point O (x, y, z) of the object on the 3D image and may be calculated according to Equation 6 below.

Here, θ _x is the x-axis projection angle, θ _y is the y-axis projection angle, and l is a fixed distance.

In addition, B _{s , t} (x _p , y _p ) in Equation 5 may be configured to be calculated according to Equation 7 as a phase term.

이다.From here,

to be.

The second lens unit 160 transmits a plane wave emitted through the SLM unit 140 to form a predetermined focal length.

The CCD unit 170 forms an image according to the distance from the second lens unit 160.

The CCD controller 180 displays an image formed by the CCD unit 170 on the display. The CCD controller 180 may be configured to capture an image according to a reproduction distance and display the image on a predetermined display configured in the CCD controller 180. The CCD controller 180 may be configured to arbitrarily control the reproduction distance and rotation of the Fourier hologram by changing the position of the CCD unit 170.

Although described with reference to the embodiments above, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the invention as set forth in the claims below. Could be.

110: laser light source
120: first lens unit
130: mirror portion
140: SLM part
150: hologram synthesis
160: second lens unit
170: CCD unit
180: CCD control unit

Claims (8)

Photographing an object from all directions to generate a plurality of 2D images;
Converting the generated 2D image into one 3D image;
Converting each point O (x, y, z) of the object on the converted 3D image into a point P _{s, t} (x _p , y _p ) projected on an orthogonal projection surface;
Calculating a phase term B _{s, t} (x _p , y _p ) from each point O (x, y, z) of the object, and
Multiply the calculated P _{s, t} (x _p , y _p ) and the calculated B _{s, t} (x _p , y _p ) and multiply the multiplied values with respect to the x _p and y _p to obtain a Fourier hologram H ( calculating s, t),
The step of calculating and converting each point O (x, y, z) of the object on the converted 3D image into a point P _{s, t} (x _p , y _p ) projected on an orthogonal projection plane,
[Mathematical Expression]

,
Calculating P _{s, t} (x _p , y _p ) according to the above equation,
Here, θ _x is the x-axis projection angle, θ _y is the y-axis projection angle, ㅣ is a fixed distance,
Computing a phase term B _{s, t} (x _p , y _p ) from each point O (x, y, z) of the object,
[Mathematical Expression]

,
Calculating the phase term B _{s, t} (x _p , y _p ) according to the above equation,
Where b =

ego,
Θ _x and θ _y are
Fourier hologram generation method for a three-dimensional object using multiple orthogonal projection images, each characterized in the range of-5 ° to + 5 °. delete delete delete A laser light source unit emitting laser light;
A first lens unit configured to transmit the emitted laser light to form a plane wave;
A mirror unit reflecting the formed plane wave;
A spatial light modulator (SLM) unit for receiving and radiating the reflected plane wave;
A hologram synthesis unit for synthesizing a Fourier hologram from a 3D image and forming a synthesized Fourier hologram on the SLM unit;
A second lens unit configured to transmit a plane wave emitted through the SLM unit to form a predetermined focal length;
A charge coupled device (CCD) unit configured to form an image according to a distance from the second lens unit;
A CCD controller which displays the formed image on a display,
The hologram synthesis unit,
[Mathematical Expression]

Synthesize Fourier hologram H (s, t) according to the above equation,
Here, P _{s, t} (x _p , y _p ) is a point projected on an orthogonal projection surface from a point O (x, y, z) of an object on the 3D image, and calculated according to the following equation,
[Mathematical Expression]

,
Here, θ _x is the x-axis projection angle, θ _y is the y-axis projection angle, l is a fixed distance,
Θ _x and θ _y are
Each in the range of −5 ° to + 5 °,
The B _{s, t} (x _p , y _p ) is calculated according to the following equation as a phase term,
[Mathematical Expression]

From here,

ego,
The CCD control unit,
Change the position of the CCD unit to arbitrarily control the reproduction distance and rotation of the Fourier hologram,
The laser light source unit,
A Fourier hologram reproduction apparatus for a three-dimensional object using multiple orthogonal projection images, which emits laser light having a wavelength of 405 nm, 532 nm or 633 nm. delete delete delete

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