Apparatus and method for measuring quality of holographic image

Patent metadata

Field	Value
Publication number	US-9500470-B2
Application number	US-201514703988-A
Country	US
Kind code	B2
Filing date	May 5, 2015
Priority date	Aug 11, 2014
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

An apparatus and a method for measuring quality of a holographic image are disclosed. The apparatus for measuring the quality of the holographic image may include an obtaining unit to obtain a hologram, a reconstruction unit to reconstruct a three-dimensional (3D) holographic image by irradiating the hologram with a light source, a measuring unit to measure depth of the reconstructed holographic image, and an analysis unit to analyze depth representation quality of the holographic image base on the measured depth of the holographic image.

First claim

What is claimed is:

1. An apparatus for measuring quality of a holographic image, the apparatus comprising:
an obtaining unit to obtain a hologram;
a reconstruction unit to reconstruct a three-dimensional (3D) holographic image by irradiating the hologram with a light source;
a measuring unit to measure depth of the reconstructed holographic image; and
an analysis unit to analyze depth representation quality of the holographic image based on the measured depth of the holographic image.

2. The apparatus of claim 1 , wherein the analysis unit compares the depth of the holographic image with depth of an original image associated with an object and analyzes the depth representation quality based on a comparison result.

3. The apparatus of claim 1 , wherein the obtaining unit receives input of red, green and blue (RGB) brightness information and 3D information on an object and obtains the hologram using the input RGB brightness information and 3D information.

4. The apparatus of claim 1 , wherein the obtaining unit comprises a beam splitter to equally split beams to respectively transmit the beams to an object and a mirror; and a camera to obtain the hologram corresponding to an interference pattern of beams reflected from the object with respect to beams reflected from the mirror.

5. The apparatus of claim 1 , wherein the reconstruction unit comprises a laser unit to generate a laser as the light source; a collimator to output the generated laser as enlarged plane waves; a spatial light modulator (SLM) to reflect light modulated from the plane waves into a space when the enlarged plane waves are incident; and a beam splitter to change a direction of at least part of the light reflected from the SLM to spread the light.

6. The apparatus of claim 1 , wherein the measuring unit detects 3D information from the reconstructed holographic image and measures the depth of the reconstructed holographic image using the detected 3D information.

7. The apparatus of claim 6 , wherein the measuring unit comprises a lens array comprising a plurality of lenses disposed at different positions to receive light associated with the reconstructed holographic image and to spread the light to different positions depending on a direction of the received light; and an image sensor to receive at least part of the spread light and to detect a plurality of elemental images as the 3D information using the received light.

8. The apparatus of claim 7 , wherein the measuring unit further comprises a measuring module unit to detect the same object points from the elemental images and to compare positional differences among the object points to measure the depth of the holographic image.

9. The apparatus of claim 7 , wherein the measuring unit further comprises a measuring module unit to spread light rays associated with the elemental images to a virtual pinhole array which transmits only light rays at certain angles depending on a position of a pixel to identify distribution of the spread light rays on a depth surface, to obtain focal images on the depth surface based on the identified distribution, and to detect a depth surface on which a focus of an object is formed from the focal images to measure the depth of the holographic image.

10. A method of measuring quality of a holographic image, the method comprising:
obtaining a hologram;
reconstructing a three-dimensional (3D) holographic image by irradiating the hologram with a light source;
measuring depth of the reconstructed holographic image; and
analyzing depth representation quality of the holographic image based on the measured depth of the holographic image.

11. The method of claim 10 , wherein the analyzing of the depth representation quality of the holographic image comprises comparing the depth of the holographic image with depth of an original image associated with an object and analyzing the depth representation quality based on a comparison result.

12. The method of claim 10 , wherein the obtaining of the hologram comprises receiving input of red, green and blue (RGB) brightness information and 3D information on an object and obtaining the hologram using the input RGB brightness information and 3D information.

13. The method of claim 10 , wherein the obtaining of the hologram comprises equally splitting, by a beam splitter, beams to respectively transmit the beams to an object and a mirror; and obtaining, by a camera, the hologram corresponding to an interference pattern of beams reflected from the object with respect to beams reflected from the mirror.

14. The method of claim 10 , wherein the reconstructing of the holographic image comprises generating, by a laser unit, a laser as the light source; outputting, by a collimator, the generated laser as enlarged plane waves; reflecting, by a spatial light modulator (SLM), light modulated from the plane waves into a space when the enlarged plane waves are incident; and changing, by a beam splitter, a direction of at least part of the light reflected into the space to spread the light.

15. The method of claim 10 , wherein the measuring of the depth of the reconstructed holographic image comprises detecting 3D information from the reconstructed holographic image and measuring the depth of the reconstructed holographic image using the detected 3D information.

16. The method of claim 15 , wherein the detecting of the 3D information comprises receiving, by a lens array, light associated with the reconstructed holographic image to spread the light to different positions depending on a direction of the received light; and receiving, by an image sensor, at least part of the spread light and detecting a plurality of elemental images as the 3D information using the received light.

17. The method of claim 16 , wherein the measuring of the depth of the reconstructed holographic image using the detected 3D information comprises detecting, by a measuring module unit, the same object points from the elemental images and comparing positional differences among the object points to measure the depth of the holographic image.

18. The method of claim 16 , wherein the measuring of the depth of the reconstructed holographic image using the detected 3D information comprises spreading, by a measuring module unit, light rays associated with the elemental images to a virtual pinhole array which transmits only light rays at certain angles depending on a position of a pixel to identify distribution of the spread light rays on a depth surface, obtaining focal images on the depth surface based on the identified distribution, and detecting a depth surface on which a focus of an object is formed from the focal images to measure the depth of the holographic image.

Assignees

• Electronics & Telecommunications Res Inst

Inventors

• Lee Soo Hyun
• Nam Je Ho
• Kim Jin Woong
• Moon Kyung Ae
• Jang Eun Young

Classifications

• G03H2001/221

  Element having optical power, e.g. field lens · CPC title

• G01B11/026 Primary

  by measuring distance between sensor and object (G01B11/0608 takes precedence) · CPC title

• G03H2001/2247

  for testing the hologram or holobject · CPC title

• G03H2001/2281

  Particular depth of field · CPC title

• G03H2223/19

  Microoptic array, e.g. lens array · CPC title