Holographic display apparatus and operating method thereof

1. A holographic display apparatus comprising:

a processor configured to identify a representative depth from 3D image data in a first direction, which is a depth direction, calculate a computer generated hologram (CGH) corresponding to the representative depth on the 3D image data, and expand an eye box in a second direction perpendicular to the first direction by modulating a phase of the CGH based on a reference scattering angle to obtain a modulated CGH;

a spatial light modulator configured to generate a hologram image by modulating light based on the modulated CGH; and

a focus optical system configured to form the hologram image generated by the spatial light modulator at the representative depth,

wherein the processor is further configured to modulate the CGH with a random phase less than or equal to the reference scattering angle, and the reference scattering angle is less than or equal to a viewing angle.

2. The holographic display apparatus of claim 1 , wherein the reference scattering angle is less than or equal to 5 degrees.

3. The holographic display apparatus of claim 1 , wherein the processor is further configured to calculate the CGH such that an object in the 3D image data, having a depth different from the representative depth before the calculation has the representative depth after the calculation.

4. The holographic display apparatus of claim 3 , wherein the processor is further configured to correct the object based on binocular parallax.

5. The holographic display apparatus of claim 4 , wherein the processor is further configured to change at least one of a size, a position, and a luminance of the object based on the binocular parallax.

6. The holographic display apparatus of claim 1 , wherein the processor is further configured to analyze at least one of a depth map and a color map included in the 3D image data to determine the representative depth.

7. The holographic display apparatus of claim 6 , wherein the processor is further configured to analyze saliency information from the color map to determine the representative depth.

8. The holographic display apparatus of claim 1 , wherein the processor is further configured to determine the representative depth with respect to each of a plurality of frames included in the 3D image data.

9. The holographic display apparatus of claim 8 , wherein the processor is further configured to control at least one of the spatial light modulator and the focus optical system such that each of the plurality of frames is displayed at the representative depth.

10. The holographic display apparatus of claim 1 , wherein the holographic display apparatus is a wearable apparatus.

11. The holographic display apparatus of claim 1 , further comprising:

an image converging member configured to change at least one of a first light path of light corresponding to the hologram image and a second light path of external light corresponding to an external image to converge the hologram image and the external image corresponding to one region.

12. A holographic display method comprising:

identifying a representative depth in a first direction from 3D image data, the first direction being a depth direction;

calculating a computer generated hologram (CGH) corresponding to the representative depth on the 3D image data;

expanding an eye box in a second direction perpendicular to the first direction by modulating a phase of the CGH based on a reference scattering angle to obtain a modulated CGH;

generating a hologram image by modulating light based on the modulated CGH; and

forming the generated hologram image at the representative depth,

wherein the modulating the phase of the CGH comprises:

modulating the CGH with a random phase less than or equal to reference scattering angle,

wherein the reference scattering angle is less than or equal to a viewing angle.

13. The holographic display method of claim 12 , wherein the reference scattering angle is less than or equal to 5 degrees.

14. The holographic display method of claim 12 , wherein the calculating of the CGH comprises:

obtaining the CGH such that an object in the 3D image data having depth information different from the representative depth before the calculation has the representative depth after the calculation.

15. The holographic display method of claim 14 , further comprising:

correcting the object based on binocular parallax.

16. The holographic display method of claim 15 , wherein the correcting comprises:

changing at least one of a size, a position, and a luminance of the object based on the binocular parallax.

17. The holographic display method of claim 12 , wherein the identifying of the representative depth comprises:

determining the representative depth by analyzing at least one of a depth map and a color map included in the 3D image data.

18. The holographic display method of claim 17 , wherein the determining of the representative depth comprises:

determining the representative depth by analyzing saliency information from the color map.

19. The holographic display method of claim 17 , wherein the determining of the representative depth comprises:

determining the representative depth with respect to each of a plurality of frames included in the 3D image data.

20. The holographic display method of claim 12 , further comprising:

converging the hologram image and an external image corresponding to external light to one region by changing at least one of a first light path of light corresponding to the hologram image and a second light path of the external light corresponding to the external image.