KR101598615B1 - A Method of Arbitrary Viewpoint/Disparity Stereoscopic Image Generation from a Digital Hologram - Google Patents

Abstract

The present invention relates to a method for generating an arbitrary viewpoint/disparity stereoscopic image from a digital hologram, which generates the stereoscopic image from the digital hologram using Fresnel transform, wherein the size of an image is adjusted using the size of a partial hologram and the disparity of the image is adjusted using the distance between the centers of two partial holograms. The method for generating the arbitrary viewpoint/disparity stereoscopic image from the digital hologram comprises the steps of: (a) receiving a digital hologram image; (b) extracting first and second partial hologram images from the digital hologram image; (c) acquiring first and second playback images from the first and second partial hologram images, respectively; and (e) generating a stereoscopic image having the first and second playback images as a pair. According to the stereoscopic image generation method as described above, a user may watch an S3D image by converting an image into the stereoscopic image even if the user does not have a hologram display device, the size and resolution of a stereoscopic screen may be adjusted as desired, and the disparity of the acquired stereoscopic image may be clearly expressed as desired.

Description

[0001] The present invention relates to a method of generating a stereoscopic image of an arbitrary viewpoint and an arbitrary parallax from a digital hologram,

A stereoscopic image is generated from a digital hologram using Fresnel-transform, the size of the image is adjusted to the size of the partial hologram, the parallax of the image is adjusted to a distance between the centers of the two partial holograms, And a method of generating a stereoscopic image having an arbitrary time difference.

Recently, the desire for stereoscopic 3-dimensional (S3D) images triggered by the movie 'Avatar' has solved the inconvenience of wearing spectacles, and has led to the desire for complete stereoscopic vision. The inconvenience of wearing spectacles can be solved by the non-rigid 3D, but the uncomfortable feeling is not solved because the technical characteristics of the non-rigid 3D display increase the degree of dizziness and tiredness [Non-Patent Document 1]. Therefore, the hologram invented by Dennis Gabor in 1948 is a technique for displaying an image providing a complete stereoscopic image in a space, and recent interest is increasing. [Non-Patent Document 2] The digital hologram has been invented so that the hologram can be provided with the current system [Non-Patent Document 3].

A hologram is a fringe pattern caused by the interference of two lights. One of the two lights uses a reference wave and the other uses an object wave reflected from the object. This hologram can obtain a high-quality image when a recording medium is sufficiently fine to record a fringe pattern. In the case of a digital hologram, a special device for diffracting light according to a fringe pattern is required in order to display a hologram, and a typical example thereof is a spatial light modulator (SLM). The image quality and the viewing angle of the hologram image are determined according to the resolution and the size of the apparatus. In order to have sufficient resolution, the size of the pixel should be 1 μm or less [Non-Patent Document 4]. In addition, a large number of pixels are required to have such a resolution and a screen size that is not inconvenient for viewers to watch, and accordingly, much data is required. The SLM pixel size has not yet been miniaturized to 1 μm, and the size of the currently available SLM is 10 cm × 10 cm or less in most cases.

Nonetheless, research on holograms is increasing exponentially. This includes not only the acquisition / generation of digital holograms, hologram image display but also compression of digital hologram data [Non-Patent Document 5], information protection [Non-Patent Document 6], information security [Non Patent Document 7], and even digital hologram data And a system for service [Non-Patent Document 8]. In particular, non-patent document 9 proposes a system for displaying a hologram image only near the viewer's viewpoint and displaying a two-dimensional image at the other part in order to popularize the hologram image at the present time. In other words, although technical researches for digital hologram data have been widely performed, development of a device for displaying digital hologram video is not sufficient yet, and it is still expensive.

Although the digital hologram data is provided on the receiving side, it is possible to consider an intermediate stage between the situation of using the present S3D display device without the hologram display device and the state of preparing the hologram display device of perfect stereoscopic vision. A study is underway [Non-Patent Document 10-12]. These studies suggested a method to generate S3D image from digital hologram data. K. Choi et al. Proposed a method of converting two pairs of S3D images into one digital hologram and irradiating them to each eye through collimated lenses [Non-Patent Document 10], and TM Lethtimaki et al. Is generated as one digital hologram, and a method of dividing the reproduced image into a stereo image has been studied [Non-Patent Document 11]. T. Pitkaaho et al. Studied the possibility of displaying S3D image pairs from one digital hologram to various current S3D display devices [Non-Patent Document 12].

[Non-Patent Document 1] Paper: D-W. Kim, JS Yoo, and Y-H, Seo, "Display quality of 3D video and visual discomfort", Display 34, pp. 223-240, 2013. [Non-Patent Document 2] Book: S. A. Benton and V. M. Bove Jr., Holographic Imaging, John Wiley & Sons, Inc., Hoboken, NJ, 2008. [Non-Patent Document 3] Paper: E. N. Leith, and J. Upatnieks, "Reconstructed wavefronts and communication theory", JOSA, 52 (10), pp. 1123-1128, 1962. [Non-Patent Document 4] Book: U. Schnar and W. Jueptner, Digital holography, Springer, Berlin, Germany, 2005. [Non-Patent Document 5] Paper: Y-H. Seo, H-J. Choi, J-S. Yoo, G-S. Lee, C-H. Kim, S-H. Lee, and D-W. Kim, "Digital hologram compression technique by eliminating spatial correlations based on MCTF," Optics Communication, 283, pp. 4261-4270, Jul. 2010. [Non-Patent Document 6] Paper: HJ. Choi, Y-H. Seo, J-S. Yoo, D-W. Kim, "Digital watermarking technique for holography interference patterns in a transform domain," Optics and Lasers in Engineering, Vol. 46, Issue 4, pp 343-348, Apl. 2008. [Non-Patent Document 7] Paper: Y-H. Seo, H-J. Choi and D-W. Kim, "Digital hologram encryption using discrete wavelet packet transform ", Optics Communications, Volume 282, Issue 3, pp. 367-377, Jan. 2009. [Non-Patent Document 8] Paper: Y-H Seo, Y-H Lee, J-M Koo, W-Y Kim, J-S Yoo, D-W Kim, "Digital holographic video service system for natural color scene" 52 no. 11, pp. 113106-1? 8, 2013. [Non-Patent Document 9] Paper: Stephan Reichelt and Norbert Leister, "Computational hologram synthesis and representation on spatial light modulators for real-time 3D holographic imaging," ISDH 2012, pp. 1-10, 2012. [Non-Patent Document 10] Paper: K. Choi, H. Kim, and B. Lee, "Synthetic phase holograms for auto-stereoscopic image displays using a modified IFTA, Optics Express, 12 (11), pp. 2454-2461, 2004. [Non-Patent Document 11] Paper: T. M. Lethtimaki and T. J. Naughton, "Stereoscopic viewing of digital holograms of real world objects," IEEE 3DTV Conference, 2007. [Non-Patent Document 12] Paper: T. Pitkaaho and T. Naughton, "Numerical reconstruction of digital holograms for conventional 3D display," IEEE 9th Euro-American Workshop, pp.1-3, 2010. [Non-Patent Document 13] Paper: Y-H. Seo, Y-H. Lee, J-S. Yoo, and D-W Kim, "A new hardware architecture of high-performance digital hologram generator on the basis of pixel-by-pixel calculation scheme," Applied Optics, 51 (18), pp. 4003-4012, 2012. [Non-Patent Document 14] Paper: H. Yoshikawa, s. Iwase, and T. Oneda, "Fast computation of Fresnel holograms employing differences," Proc. SPIE 3956, 2000. [Non-Patent Document 15] http://www.microsoft.com/en-us/kinectforwindows/ [Non-Patent Document 16] http://vision.middlebury.edu/stereo/data/ [Non-Patent Document 17] http://www.dofpro.com/cgigallery.htm

An object of the present invention is to solve the above-mentioned problems, and it is an object of the present invention to provide a stereoscopic image generation method and a stereoscopic image generation method in which a stereoscopic image is generated from a digital hologram using Fresnel- And a method of generating a stereoscopic image of an arbitrary time point and an arbitrary time difference from a digital hologram.

According to an aspect of the present invention, there is provided a stereoscopic image generation method for generating a stereoscopic image from a digital hologram, the stereoscopic image generating method comprising: (a) receiving a digital hologram image; (b) extracting first and second partial hologram images from the digital hologram image; (c) obtaining first and second reproduced images from the first and second partial hologram images, respectively; And (e) generating a stereoscopic image having a pair of the first and second reproduced images.

According to another aspect of the present invention, there is provided a stereoscopic image generating method for generating a stereoscopic image of a random viewpoint and an arbitrary parallax from a digital hologram, wherein the first and second partial hologram images have the same horizontal and vertical sizes, And the central axes of the directions are the same.

According to another aspect of the present invention, there is provided a stereoscopic image generating method of a random viewpoint and a random viewpoint from a digital hologram, wherein in the step (b), a resolution ratio of the first and second partial hologram images, And is extracted so as to be equal to the resolution ratio of the hologram image.

Further, the present invention is a stereoscopic image generating method of a random viewpoint and an arbitrary viewpoint from a digital hologram, wherein in the step (c), the reproduced image is generated in the partial hologram image using Fresnel- do.

The present invention also provides a method for generating a stereoscopic image at an arbitrary time point and an arbitrary time point from a digital hologram, the method further comprising: (d) performing up-sampling or down-sampling of the obtained reproduced image .

In the method of generating a stereoscopic image at a certain time point and an arbitrary time point from a digital hologram, the size of the reproduced image is determined by the pixel size and resolution of the reproduced image, Is determined by the pixel size of the reproduced image and the distance between the center points of the first and second partial hologram images.

The present invention is characterized in that, in a method of generating a stereoscopic image at an arbitrary time point and an arbitrary time point from a digital hologram, the parallax d of the first and second reproduced images is determined by the following [Expression 1].

[Equation 1]

Wherein m _p is a ratio of a pixel size of the reproduced image to a pixel size of the digital hologram image, m _r is a ratio of a resolution of the reproduced image to a resolution of the digital hologram image, and X '/ A is a ratio Δx / Δα is the pixel size ratio of the digital hologram image to the object image, and D _h is the center-to-center distance of the first and second partial hologram images.

The present invention also provides a stereoscopic image generation method for generating a stereoscopic image at arbitrary time points and arbitrary timings from a digital hologram, wherein when the reproduced image is up-sampled or down-sampled to multiply the pixel size by q, .

As described above, according to the stereoscopic image generation method of arbitrary viewpoint and arbitrary disparity from the digital hologram according to the present invention, when the service of digital hologram data is provided, even if the user does not have the hologram display device, So that the effect of viewing the S3D image is obtained. That is, in a transitional period in which a hologram is introduced, for example, a current S3D display device and a holographic display device are mixed, a receiver without a hologram display device can use the hologram providing service as a conventional S3D display device .

According to the stereoscopic image generation method of arbitrary viewpoint and arbitrary disparity from the digital hologram according to the present invention, the size and parallax of the stereoscopic image are controlled through the size of the partial hologram and the distance between centers, And the resolution can be adjusted as desired, and the effect of obtaining the clearance of the obtained stereoscopic image as desired can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing a configuration of an overall system for carrying out the present invention; Fig.
FIG. 2 is a view showing a process of acquiring and reproducing an image of a digital hologram according to the present invention, which illustrates (a) an acquisition process and (b) an image reproduction process.
3 is an exemplary view of a coordinate system of digital holography according to the present invention;
4 is an exemplary view of the size of a reproduced image with respect to the size of a partial hologram according to the present invention;
FIG. 5 illustrates an example of a reproduced image according to the center shift of the partial hologram according to the present invention, wherein (a) a partial hologram, (b) left left, (c) right right, Fig.
FIG. 6 is a view showing an example of a viewpoint change of two partial holograms according to the present invention, wherein (a) is a viewpoint change, and (b) is an example of a model applied to a stereo camera.
7 is a flowchart for explaining a method of generating a stereoscopic image at a certain time point and an arbitrary time difference from a digital hologram according to an embodiment of the present invention.
8 is an exemplary view of a GUI screen for generating a digital hologram stereo image according to an experiment of the present invention;
9 is a table showing information on images used in accordance with the experiment of the present invention.
10 is a table showing parameter values of Rabbit and Billiard images according to the experiment of the present invention.
11 is an exemplary view of a red-type stereo image generated according to an experiment of the present invention, which is an example of (a) Babbit, (b) Yoonjoo, (c) Billiard image.
12 is an exemplary image of an experiment on a Baby image according to the experiment of the present invention. The example image includes (a) original left image, (b) original image, (c) depth map for left image, (d) (e) a hologram right image, and (f) a proper type hologram stereo image.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings.

In the description of the present invention, the same parts are denoted by the same reference numerals, and repetitive description thereof will be omitted.

First, examples of the configuration of the entire system for carrying out the present invention will be described with reference to Fig.

1, a method for generating a stereoscopic image of arbitrary viewpoints and arbitrary distances from a digital hologram according to the present invention includes receiving a pair of stereoscopic images from a digital hologram (or a hologram image) May be implemented as a program system on the generating computer terminal 20. That is, the stereoscopic image generation method may be implemented by a program and installed in the computer terminal 20 and executed. A program installed in the computer terminal 20 can operate as a single program system 30. [

Meanwhile, as another embodiment, the stereoscopic image generating method may be implemented by a single electronic circuit such as an ASIC (on-demand semiconductor) in addition to being operated by a general-purpose computer. Or a dedicated terminal 30 that exclusively processes only a task of generating a pair of stereoscopic images from a digital hologram. This is called a stereoscopic image generation system. Other possible forms may also be practiced.

Next, before describing a method of generating a stereoscopic image at a certain time point and an arbitrary time point from the digital hologram according to the present invention, various features related to generation of a digital hologram and image reproduction used in the present invention 2 to Fig. 6.

First, a method of acquiring a computer-generated digital hologram and a method of reproducing an image by Fresnel transformation will be described.

Fig. 2 shows a schematic diagram of a method of (a) acquiring a digital hologram and (b) reproducing an image. The digital hologram can acquire the interference result of the reference wave and the object wave with a digital device such as a CCD camera. In general, reference and object waves are split by using a beam splitter (BS) to generate light from the same light source. To reproduce an image from the obtained hologram, a diffraction device such as an SLM (spatial light modulator) is required. When a hologram is loaded and a light is irradiated and the resultant light is irradiated by our eyes, Phase.

However, the acquisition system of FIG. 2 (a) is highly precise, expensive, and incapable of carrying, and thus has many limitations in using this apparatus. Therefore, holograms can be generated by modeling and modeling the digital hologram acquisition situation in FIG. 2 (a). This hologram is called a computer-generated hologram (CGH) Has also been studied [Non-Patent Document 13]. A typical CGH operation equation is as shown in Equation 1, and the coordinate system here is shown in FIG.

[Equation 1]

Where I _h (x, y) is a holographic pixel values of the hologram plane (hologram plane) coordinates (x, y), (A , B) , of the object plane resolution, I _O (α, β) is the object plane (object plane ) Intensity of light of coordinates (?,?), And? Represents the depth value of this coordinate, respectively. K = 2? /? Is the wave number of the light used, and? Is the wave length.

2 (b) is obtained by diffracting light according to each fringe pattern of the hologram. Particularly, in the case of a digital hologram, light is diffracted according to each hologram pixel value (Equation 1), and the result affects all the image portions of the image, and the image of a specific portion is formed by combining the influences on the portion. Although this phenomenon can be realized by using an optical system including an SLM (optical reproduction), it can also be modeled mathematically as shown in Equation 2 using Fresnel diffraction (mathematical reproduction).

&Quot; (2) "

Here, g _r (u, v) is the intensity value of light reproduced in the (u, v) pixel in the reconstruction plane, which is z ₀ away from the hologram plane, and the value of each pixel in the hologram plane Are shown in FIG. 3 and Equation 1, respectively. In Equation (2), it is assumed that the horizontal and vertical pixel size ratios and resolution ratios of the hologram plane and the reproduction plane are the same as in Equations (3) and (4) It is very common because it is assumed to be the same. Therefore, the image size ratio between the hologram plane and the reproduction plane is expressed by Equation (5).

&Quot; (3) "

&Quot; (4) "

&Quot; (5) "

Next, the size of the partial digital hologram and the size of the reproduced image according to the present invention will be described.

The size of the reproduced image can be adjusted according to Equations (3), (4) and (5). However, the size of the playback image can be adjusted without adjusting the size of the playback plane. As can be seen in equations (1) and (2), all pixels in the object plane affect each pixel in the hologram plane, and all pixels in the hologram plane affect each pixel in the reproduction plane. That is, each pixel of the hologram plane has information of the entire object at that position, and each pixel of the reproduction plane has information of the entire hologram plane. Therefore, an object can be reproduced with only a part of the given hologram or theoretically one pixel.

FIG. 4 shows images obtained by making a Rabbit image into a CGH having a resolution of 1,024 × 1,024 according to Equation (1), extracting a part of the CGH, and reproducing the Fresnel transform of Equation (2). Here, the centers of all partial holograms are the same. As can be seen from the drawing, the smaller the size of the partial hologram, the smaller the size of the reproduced image. This means that as the size of the hologram is reduced, the amount of diffracted light and the angle of illumination become smaller, and the object to be reproduced becomes smaller.

Next, the change of the viewpoint according to the position of the partial hologram according to the present invention will be described.

It can be seen that all playback images of FIG. 4 are identical in time but different in size. However, even if the same partial hologram is extracted with different center, the viewpoint of the reproduced image is different. (Fig. 5 (b), (c), (d), and (e)) in which four partial holograms (left, right, upper and lower) . As shown in the drawing, not only the position of the object is changed as the center moves, but also the viewpoint of the object is changed. This is because, as shown in the coordinate system of FIG. 3, when the position of the hologram changes, a hologram is formed by the light irradiated to the position.

FIG. 6 illustrates a viewpoint change of two partial holograms. 6 (a) shows a viewpoint change of two partial holograms for the same object, and FIG. 6 (b) shows a model in which a reproduced image of two partial holograms is applied to a stereoscopic camera. The coordinate system in both figures follows the coordinate system in Fig. As shown in FIG. 6 (a), in the present invention, the viewpoint of a specific hologram is regarded as a viewpoint at the center point, which is considered as a good reference of the viewpoint position. It is also assumed that the horizontal and vertical sizes of the two partial holograms are the same and that the two center points (L = ( _xl , y), R = ( _xr , y) Characteristics. As shown in FIG. 6A, it is assumed that the resolution ratio (X '/ Y') of the partial hologram is equal to the resolution ratio (X / Y) of the circular hologram. The resolution ratio (U '/ V') of the reproduction plane is also assumed to be the same (Equation (6)). This is so that the reproduced image has the same horizontal and vertical size ratios as the original object.

&Quot; (6) "

Therefore, the viewpoint difference D _h between the two partial holograms in the hologram plane is equal to the distance between the center points of the two partial holograms as shown in Equation (7).

&Quot; (7) "

When this is converted into the value of the reproduction plane, the viewpoint difference D in the reproduction plane is expressed by Equation (8).

&Quot; (8) "

On the other hand, FIG. 6 (b) is a diagram for modeling two partial holograms generated by two digital holograms having different horizontal positions with respect to one object. For the sake of simplicity, it is assumed here that the center of the left hologram is the same as the center of the object. In this case, since the two holograms are the same size, the irradiation angle from the object to each hologram is the same (∠h _l = ∠h _r ). Since the camera model is used in this drawing, it is assumed that the focal distance f, which is irrelevant to the generation of the digital hologram, is used, and light is gathered at the focal plane. However, this means that each hologram has the same information, except that the position of each pixel in the hologram plane changes 180 degrees. From the simple proportional expression, the focal length can be calculated as shown in Equation (9).

&Quot; (9) "

Thus, the disparity d _h in the hologram plane is given by:

&Quot; (10) "

, And the parallax d in the reproduction plane can be obtained by the following equation

&Quot; (11) "

.

wherein m _p is a ratio of a pixel size of the reproduced image to a pixel size of the digital hologram image, m _r is a ratio of a resolution of the reproduced image to a resolution of the digital hologram image, and X '/ A is a digital hologram Δx / Δα is the pixel size ratio of the digital hologram image to the object image, and D _h is the center-to-center distance of the first and second partial hologram images.

As can be seen from Equation 10 or 11, the parallax of the generated stereo image is a function of the distance between the center points of the two partial holograms, the distance between the hologram and the reproduction plane, as well as the size of the partial hologram. That is, the parallax of the two reproduced images becomes larger as the distance between the center points of the two partial holograms becomes larger and the distance between the hologram plane and the reproduction plane becomes closer. In addition, the distance between the center points of the two partial holograms is the same, but the smaller the size of the partial hologram is, the larger the parallax is relative to the size of the object. If the reproduction plane is enlarged q times by up-sampling the reproduction plane, the difference d _q is d _q = _q d.

Next, a method of generating a stereoscopic image using a partial hologram according to an embodiment of the present invention will be described with reference to FIG. 7 is a flowchart for explaining a method of generating a stereoscopic image at arbitrary time points and arbitrary time differences from a digital hologram according to the present invention.

7, the stereoscopic image generation method of the arbitrary viewpoint and the arbitrary viewpoint from the digital hologram according to the present invention includes the steps of (a) inputting a digital holographic image (S10), (b) extracting a partial hologram image (S20) (c) a reproduced image generating step S30, (d) a regenerating image size adjusting step S40, and (e) a stereoscopic three-dimensional image generating step S50. At this time, the size adjustment step S40 of the reproduced image may be omitted.

First, the digital hologram image (or the original hologram image) is input (S10).

Next, two partial holograms are extracted from the input digital hologram (S20). The two partial holograms to be extracted are referred to as first and second partial holograms, respectively.

At this time, the desired screen size and the parallax d in the two partial holograms or the reproduced image are adjusted by Expression (6), (10) or (11). Therefore, the two partial holograms can partially overlap in the circular hologram.

Preferably, the size of the two partial holograms in the horizontal and vertical directions is the same, and the y-axis of the two center points of the two partial holograms have the same value. That is, the two partial holograms are extracted so as to be located on the same horizontal line.

Preferably, the resolution ratio in the vertical and horizontal directions of each partial hologram is the same as the resolution ratio of the digital hologram image (or the original hologram image).

Next, a reconstruction image is generated from each of the two partial holograms (S30). That is, the extracted two partial holograms are reproduced to acquire left and right images. At this time, the reproduced image is obtained by the Fresnel transformation (or Fresnel transformation). As a preferable example, a Fresnel-transform equation such as equation (2) can be used. On the other hand, the reproduced images at this time will be referred to as first and second reproduced images, respectively. That is, a first reproduced image is generated from the first partial hologram image, and a second reproduced image is generated from the second partial hologram image.

Next, if an additional screen size is to be adjusted (q) by up-sampling (up / down-sampling), the images are adjusted to target (S40).

Finally, the two images are processed according to the necessary S3D data format to obtain a desired S3D image (S50).

On the other hand, the size of the reproduced image is adjusted by the pixel size (? U,? V) and the resolution (U '× V') of the reproduced image. Also, the reproduced image may be adjusted by up-sampling or down-sampling. The size of the final reproduced image is determined in consideration of all cases, the size of the partial hologram to be extracted from the hologram plane is determined, and the distance between the center points of the two partial holograms is determined according to the time difference. According to the size of the reproduced image, the parallax of the two images is adjusted by the distance (D _h ) between the center points of the two partial holograms.

Next, the effects of the present invention through experiments will be described in more detail with reference to FIGS. 8 to 10. FIG.

Any time and method of generating a stereoscopic image of an arbitrary time difference from the digital hologram according to the present invention was implemented in a National Instrument Corporation LabVIEW ^® environments. All processes except CGH generation and Fresnel transformation are implemented in C / C ++, converted into a dll file format, and stored in a library. The CGH and Fresnel transformations are implemented in NVIDIA's CUDA ^® , and GPGPU (general purposed graphic processing unit) is used. When CGH is generated, R, G and B components are separately extracted for color image, CGH of each component is generated. Image reproduction reproduces each color hologram, and the three images are combined to form a color image. For CGH generation, each color image and one black and white image depth map were used. Therefore, each component of color used the same depth map.

Figure 8 shows a GUI screen for implementing and implementing the method of the present invention. Two images on the upper left side are object information (RGB or monochrome image and depth map), and the two images on the right side show the real part and the imaginary part of CGH generated by this object information, respectively. The three images below represent anaglyph-type S3D image, which is a combination of left image, right image, and left image. The control buttons on the upper right side are buttons for controlling the parameters, including the resolution of the hologram, the parallax of the stereo image pair, the distance between the hologram plane and the reproduction plane, and the magnification factor.

The table of FIG. 9 shows the information of the images used in the experiment of the present invention. The vertical league system described in the first line [Non-Patent Document 8] is a system that the present inventor manufactured directly and includes three sets of cameras in which a RGB camera and a depth camera are separated by a cold mirror and mounted on a vertical rig have. The RGB camera used here is Alike Vision Technology's Pike ^® (1,920 × 1,080), and the depth camera is Mesa Image's SR4000 ^® (176 × 144). Since the resolution of the depth camera is low, the resolution of the image acquired by the RGB camera is reduced to match the depth image. Also used to acquire images directly to Microsoft's Kinect ^® (640 × 480) [Non-Patent Document 15]. This camera provides both depth images and RGB images of the same resolution. In addition, images of Middlebury (non-patent document 16), DOF Pro (non-patent document 17), and Rabbit image were also used.

The table in FIG. 10 lists only two representative (Rabbit and Billiard) sets of the parameters described above. The laser light frequencies used for CGH generation were 633 nm (green) and 533 nm (red). The resolution of the hologram and the reconstructed image was 1,024 × 1,024, but the image size was adjusted by changing the pixel size. The resolution of the object plane depends mostly on the source, and the image of the Middlebury site has various resolutions. The parameters except for the resolution were performed differently for each image.

FIG. 11 shows four examples in which the generated S3D images are implemented in a red-format. Since the rabbit in (a) is provided with depth map only, it is used as depth information and light intensity information. This image has a negative disparity in which the object looks forward than the actual one. Since the Yoonjoo image of (b) was obtained using the inventor's vertical rig, the resolution of the object plane was 176 × 144. This image has a positive disparity where the object appears farther away than it actually is. (c) Billiard image is created by generating CGH by reducing the resolution of DOF Pro site to 320 × 240, and this image has negative parallax.

12 is a flowchart showing a process of generating a digital hologram from a depth map c and a left image a provided by a site with respect to a Baby image received from the Middlebury site and generating a digital hologram from the left image a and the right image b (D) and (e) of the corresponding hologram image are shown in FIG. In order to make a digital hologram, the resolution of the original image and the depth map was reduced to 200 × 200. As shown in the figure, the hologram images have poor image quality compared to the original images. In addition to lowering the resolution of the object image, a part of the hologram is cut and reproduced. Also, the resolution of the hologram and the resolution of the reproduced image are sufficiently high It is not. In the figure, it can be seen that the left and right images reproduced the hologram have more volume than the two-dimensional image but the left and right images. This is because the original images do not contain depth information at all, but the hologram reproduction image contains the depth information of the hologram itself.

In the present invention, a stereoscopic image pair is generated using a digital hologram, assuming that a digital hologram is served but only a stereo-scopic 3D image display device is provided without a holographic image display device on the viewer's side, And how to adjust the time difference. As shown in the image of the experiment result of the present invention, all of the experiment images clearly showed the intended time difference, and the screen size and resolution could be adjusted as desired.

In the present invention, the image is slightly blurred because the object plane, the hologram plane, and the reproduction plane of sufficient resolution are not used in consideration of the CGH generation time and the like. However, when data having sufficient resolution is used, a clearer and clearer image can be obtained.

Therefore, the method according to the present invention can generate stereoscopic 3D as well as multi-view images using hologram data.

Although the present invention has been described in detail with reference to the above embodiments, it is needless to say that the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the present invention.

10: digital holographic image 20: computer terminal
30: Program system

Claims (8)

A stereoscopic image generating method for generating a stereoscopic image from a digital hologram image, the stereoscopic image generating method comprising:
(a) receiving a digital hologram image;
(b) extracting first and second partial hologram images from the digital hologram image;
(c) obtaining first and second reproduced images from the first and second partial hologram images, respectively; And
(e) generating a stereoscopic image having one pair of the first and second playback images,
Wherein the size of the reproduced image is determined by the pixel size and resolution of the reproduced image and the parallax of the first and second reproduced images is determined by a distance between a pixel size of the reproduced image and a center distance between the center points of the first and second partial hologram images Lt; / RTI >
Wherein a parallax d of the first and second reproduced images is determined by the following equation 1: " (1) "
[Equation 1]

Wherein m _p is a ratio of a pixel size of the reproduced image to a pixel size of the digital hologram image, m _r is a ratio of a resolution of the reproduced image to a resolution of the digital hologram image, and X '/ A is a ratio Δx / Δα is the pixel size ratio of the digital hologram image to the object image, and D _h is the center-to-center distance of the first and second partial hologram images.
The method according to claim 1,
Wherein the first partial hologram image and the second partial hologram image are extracted so that the horizontal and vertical directional magnitudes are the same and the central axis of the horizontal direction is the same. A method for generating a stereoscopic image.
The method according to claim 1,
Wherein the resolution ratio of the first and second partial hologram images in the vertical and horizontal directions is extracted to be the same as the resolution ratio of the digital hologram image in step (b) / RTI >
The method according to claim 1,
Wherein the reproduced image is generated in the partial hologram image using the Fresnel-transform in the step (c).
The method of claim 1,
(d) performing up-sampling or down-sampling on the reproduced image obtained. The stereoscopic image generating method of any of the preceding claims,
delete delete The method according to claim 1,
Wherein the reproduced image is up-sampled or down-sampled, and when the pixel size is multiplied by q, the parallax of the reproduced image is also determined to be q times, and a method for generating a stereoscopic image of a random viewpoint and an arbitrary parallax from the digital hologram.

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