KR101353966B1 - Method for reconstructing all focused hologram and apparatus using the same - Google Patents

Abstract

An all focused hologram restoration method and apparatus are provided. In the digital hologram restoration method according to an embodiment of the present invention, digital hologram data is restored to a plurality of digital holograms according to a focal length, and a plurality of digital holograms are combined to generate one digital hologram. As a result, all parts of the hologram can be focused at the time of digital hologram restoration, thereby enhancing the aesthetics as well as increasing the aesthetics and enhancing the practicality by increasing image recognition.

Description

METHOD FOR RECONSTRUCTING ALL FOCUSED HOLOGRAM AND APPARATUS USING THE SAME}

The present invention relates to hologram reconstruction, and more particularly, to a method and apparatus for reconstructing digital hologram data into a visible hologram.

When digital hologram data is restored to the display, it is restored to a specific focal length. The reconstructed digital hologram is focused on a specific focal length so that the focused part appears sharp, but the unfocused part is blurred.

Blurred parts act as a factor for reducing aesthetics and perception not only for the parts themselves but also for the entire restored hologram. Accordingly, there is a need for a solution to solve the problem of regional focus mismatch for the hologram restored on the display.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a digital hologram restoration method and apparatus for focusing on all parts of the hologram.

According to an embodiment of the present invention, a digital hologram restoration method includes: recovering digital hologram data into a plurality of digital holograms according to a focal length; And combining the plurality of digital holograms to generate one digital hologram.

The digital hologram restoration method may further include calculating a focusing parameter for each of the plurality of digital holograms. The generating step may further include generating the focusing parameter calculated in the calculating step. As a basis, one digital hologram may be generated by combining the plurality of digital holograms.

In the calculating step, for each of the plurality of digital holograms, focusing parameters may be calculated for each pixel.

The focusing parameter may be a parameter representing a degree of focus in each pixel.

The focusing parameter may be any one of a variation, a standard deviation, a gradient, and a mean of pixel values calculated while shifting a window.

In the generating step, a digital hologram may be generated by combining pixels having the largest focusing parameter.

In addition, the focal length may be a distance from the hologram plane to the image plane.

On the other hand, according to another embodiment of the present invention, the digital hologram restoration apparatus, the plurality of restoration units for restoring the digital hologram data into a plurality of digital holograms according to the focal length; And a selector configured to combine the plurality of digital holograms restored by the plurality of restoration units to generate one digital hologram.

As described above, according to the present invention, all parts of the hologram can be focused when the digital hologram is restored. Accordingly, the hologram quality can be improved, thereby increasing the aesthetics and increasing the practicality due to the increase in image recognition.

1 is a diagram illustrating a digital hologram restoration device according to an embodiment of the present invention;
2 is a diagram schematically illustrating a concept in which focusing parameters are calculated from digital holograms, and
3 is a diagram illustrating a digital hologram combining process by focusing parameter comparison / selection.

Hereinafter, with reference to the drawings will be described the present invention in more detail.

1 is a diagram illustrating a digital hologram restoration device according to an embodiment of the present invention. The illustrated digital hologram restoring apparatus restores the visible digital hologram using the input digital hologram data, and restores the focus on all pixels of the digital hologram. The focused digital hologram at every pixel will be referred to as an All Focused digital hologram (pre-focused digital hologram).

The input digital hologram data may be received from an external device stored in a storage medium or connected to a wired or wireless connection.

As shown in FIG. 1, the digital hologram restoration apparatus according to the present embodiment includes a plurality of digital hologram restoration units 110-1 to 110 -N and a plurality of focusing parameter calculators 120-1 to 120 -N. And a comparator 130 and a selector 140.

The digital hologram restoration units 110-1 to 110 -N restore the input digital hologram data to different focal lengths d. Here, the focal length d means the distance from the hologram plane to the image plane.

As a result, the N digital holograms having different focal lengths are restored and output from the digital hologram restoration units 110-1 to 110 -N. Specifically,

1) The digital hologram restoration unit-1 (110-1) restores the input digital hologram data to the focal length-1 (d1), and outputs the digital hologram-1,

2) the digital hologram restoration unit-2 (110-2) restores the input digital hologram data to the focal length-2 (d2), and outputs the digital hologram-2,

...,

N) The digital hologram restoration unit-N 110-N restores the input digital hologram data to the focal length-N (dN) and outputs the digital hologram-N.

For digital hologram reconstruction, the digital hologram reconstruction units 110-1 to 110 -N may use a Fresnel Transform or Convolution Method. Of course, other methods may be used.

Since the focal lengths applied by the digital hologram reconstruction units 110-1 to 110 -N are different, the positions of the focused portions of the digital holograms reconstructed by the digital hologram reconstruction units 110-1 to 110 -N are different. Are different.

The focusing parameter calculators 120-1 to 120 -N calculate focusing parameters for each of the digital holograms restored by the digital hologram restorers 110-1 to 110 -N.

1) the focusing parameter calculating unit-1 120-1 calculates a focusing parameter for the digital hologram-1 restored by the digital hologram restoring unit-1110-1,

2) the focusing parameter calculating unit-2 (120-2) calculates the focusing parameters for the digital hologram-2 restored by the digital hologram restoring unit-2 (110-2),

...,

N) The focusing parameter calculator-N 120-N calculates the focusing parameters for the digital hologram-N reconstructed by the digital hologram reconstructor-N 110-N.

The focusing parameter is calculated for all the pixels constituting the digital hologram and is a parameter indicating the degree of focus in the pixels. Since it is calculated for each pixel, for example, when the size of the digital hologram is M × M, the number of focusing parameters is M × M.

Thus, 1) M × M focusing parameters are calculated for digital hologram-1, 2) M × M focusing parameters are calculated for digital hologram-2, and N) for digital hologram-N. M × M focusing parameters are calculated.

2 schematically illustrates the concept that the focusing parameters are calculated from the digital holograms. As shown in FIG. 2, the focusing parameters may be calculated for all pixels of the digital hologram while shifting a window of n-by-n block size.

The focusing parameter calculation using the window of the n-by-n block size is possible according to Equation 1 below.

Here, "i" and "j" are coordinates included in a window of n-by-n block size, and "y" means a pixel value. In Equation 1, variance of pixel values is assumed as a focusing parameter.

Equation 1 may be modified according to needs and specifications, and other parameters other than dispersion as focusing parameters may be applied as focusing parameters. Other parameters that can be applied include Standard Deviation, Gradient, and Mean.

Regardless of which parameter is used, the higher the focused pixel, the larger the focusing parameter, and the lower focused pixel, the larger the blurring, the smaller the focusing parameter.

The comparator 130 compares the focusing parameters calculated by the focusing parameter calculators 120-1 to 120 -N in units of pixels, and transfers the comparison result to the selector 140.

Specifically, when the size of the digital hologram is M × M, the comparison unit 130,

1) information on which digital hologram has the largest focusing parameter for the (1,1) pixel of the digital holograms (Digital Hologram-1 to Digital Hologram-N),

2) information on which digital hologram has the largest focusing parameter for the (1,2) pixel of the digital holograms (Digital Hologram-1 to Digital Hologram-N),

3) information on which digital hologram has the largest focusing parameter for the (1,3) pixel of the digital holograms (Digital Hologram-1 to Digital Hologram-N),

...,

M × M) information about the digital hologram having the largest focusing parameter for the (M, M) pixel among the digital holograms (digital hologram-1 to digital hologram-N) is transmitted to the selection unit 140.

Referring to the comparison result received from the comparator 130, the selector 140 generates one digital hologram by combining the digital holograms restored by the digital hologram reconstruction units 110-1 to 110-N.

Specifically, the selection unit 140,

1) (1,1) pixels of the digital hologram with the largest focusing parameters for (1,1) pixels,

2) (1,2) pixels of the digital hologram with the largest focusing parameters for (1,2) pixels,

3) (1,3) pixels of the digital hologram with the largest focusing parameters for (1,3) pixels,

...,

One digital hologram is generated by combining the (M, M) pixels of the digital hologram with the largest focusing parameters for the M × M) (M, M) pixels. E.g,

1) When the digital hologram having the largest focusing parameter for the (1,1) pixel is the digital hologram-3, the selector 140 selects the (1,1) pixel of the digital hologram-3 from the (1,1) pixel of the All Focused digital hologram. , 1) select it in pixels,

2) When the digital hologram having the largest focusing parameter for the (1,2) pixel is the digital hologram-1, the selector 140 selects the (1,2) pixel of the digital hologram-1 from the (1,2) pixel of the All Focused digital hologram. , 2) pixels,

...,

When the digital hologram having the largest focusing parameter for the M × M) (M, M) pixels is the digital hologram-10, the selector 140 selects the (M, M) pixels of the digital hologram-10 of the All Focused digital hologram. Select (M, M) pixels,

The selected pixels are combined to create one All Focused Digital Hologram.

3 shows a comparison method by the comparison unit 130 and a digital hologram combination method by the selection of the selection unit 140. As shown in FIG. 3, the focusing parameters are compared by the comparator 130, and the selector 140 selects / combines the pixels with reference to the comparison result.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention.

110-1 to 110-N: digital hologram restoration unit
120-1 to 120-N: focusing parameter calculator
130:
140: selection unit

Claims (8)

Restoring one digital hologram data into a plurality of digital holograms according to different focal lengths; And
And combining the plurality of digital holograms to generate one digital hologram.
The method of claim 1,
Calculating a focusing parameter for each of the plurality of digital holograms;
The generating step,
And a digital hologram is generated by combining the plurality of digital holograms based on the focusing parameter calculated in the calculating step.
3. The method of claim 2,
Wherein,
And calculating focusing parameters for each of the plurality of digital holograms on a pixel-by-pixel basis.
The method of claim 3, wherein
The focusing parameter is
And a parameter representing a degree of focus in each pixel.
5. The method of claim 4,
The focusing parameter is
A method of restoring a digital hologram, characterized in that any one of a variance, a standard deviation, a gradient, and a mean of calculated pixel values while shifting a window.
The method of claim 3, wherein
The generating step,
And a focusing parameterizer combines the largest pixels to produce one digital hologram.
The method of claim 1,
The focal length is,
And a distance from the hologram plane to the image plane.
A plurality of reconstruction units for reconstructing one digital hologram data into a plurality of digital holograms according to different focal lengths; And
And a selector for generating one digital hologram by combining the plurality of digital holograms restored by the plurality of restoration units.

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