Method and system for producing computer generated holograms realizing real time holographic video production and display

• US 6,130,957 A
• Filed: 12/05/1997
• Issued: 10/10/2000
• Est. Priority Date: 12/06/1996
• Status: Expired due to Fees

• Current Assignee: Nippon Telegraph and Telephone Corporation
• Original Assignee: Nippon Telegraph and Telephone Corporation
• Inventors: Suzuki, Satoshi, Horikoshi, Tsutomu, Higuchi, Kazuhito, Akimoto, Takaaki
• Primary Examiner(s): CHANG, JON CARLTON
• Application Number:
  US08/985,817
• Time in Patent Office: 1,040 Days
• Field of Search: 382/107, 382/236, 382/210, 382/100, 348/40, 348/699, 359/9, 359/1, 359/29, 359/35, 250/550, 356/347
• US Class Current: 382/107
• CPC Class Codes: G03H 1/0808 Methods of numerical synthesis, e.g. coherent ray tracing [CRT], diffraction specific
• CPC Class Codes: G03H 1/2294 Addressing the hologram to an active spatial light modulator
• CPC Class Codes: G03H 1/268 Holographic stereogram
• CPC Class Codes: G03H 1/34 Systems for reducing the space-spatial bandwidth product
• CPC Class Codes: G03H 2001/0825 Numerical processing in hologram space, e.g. combination of the CGH [computer generated hologram] with a numerical optical element
• CPC Class Codes: G03H 2001/0833 Look up table
• CPC Class Codes: G03H 2001/303 Interleaved sub-holograms, e.g. three RGB sub-holograms having interleaved pixels for reconstructing coloured holobject
• CPC Class Codes: G03H 2210/30 3D object
• CPC Class Codes: G03H 2210/32 3D+2D, i.e. composition of 3D and 2D sub-objects, e.g. scene in front of planar background
• CPC Class Codes: G03H 2210/40 Synthetic representation, i.e. digital or optical object decomposition
• CPC Class Codes: G03H 2210/45 Representation of the decomposed object
• CPC Class Codes: G03H 2210/452 into points
• CPC Class Codes: G03H 2210/56 Multiple objects, e.g. each in different environment
• CPC Class Codes: G03H 2210/62 Moving object
• CPC Class Codes: G03H 2226/05 Means for tracking the observer
• CPC Class Codes: G03H 2240/56 Resolution
• CPC Class Codes: G03H 2240/62 Sampling aspect applied to sensor or display

Abstract

A scheme for producing computer generated holograms in which a motion vector of each object to be displayed is detected, objects are classified according to their motions, a hologram fringe pattern for each classified group of objects is calculated separately by image processing stored basic patterns, and a hologram to be displayed is produced by synthesizing all separately calculated hologram fringe patterns. In another aspect, a gaze point of the observer is determined, and a hologram to be displayed is produced by using high resolution hologram fringe patterns for objects located at the gaze point and low resolution hologram fringe patterns for regions other than the gaze point. In another aspect, a distance between each display target object and a hologram plane is obtained, a region of calculations for interference fringes due to each display target object is limited according to the obtained distance, interference fringes due to each display target object are separatedly calculated within the limited region of calculations, and a hologram to be displayed is produced by synthesizing separately calculated interference fringes due to all display target objects.

Claims

1. A method for producing computer generated holograms in a form of holographic video by calculating hologram fringe patterns, comprising the steps of:

storing basic patterns for wavefronts of lights from objects;

detecting a motion vector of each object to be displayed after a prescribed time;

classifying the objects into a plurality of groups according to motions of the objects indicated by the motion vector of each object, such that objects in an identical motion are classified as belonging to an identical group;

calculating a hologram fringe pattern for each classified group of objects separately by initially using a corresponding one of the basic patterns and subsequently image processing each calculated hologram fringe pattern; and

producing a hologram to be displayed after the prescribed time by synthesizing all separately calculated hologram fringe patterns.

2. The method of claim 1, wherein the calculating step calculates the hologram fringe pattern by carrying out one or both of a translation processing and a rotation processing on the corresponding one of the basic patterns.

3. The method of claim 1, wherein the calculating step calculates the hologram fringe pattern for only those groups of objects which are moving according to the motion vector of each object, and the producing step produces the hologram by synthesizing all separately calculated hologram fringe patterns with original hologram fringe patterns for objects which are not in motion.

4. A system for producing computer generated holograms in a form of holographic video by calculating hologram fringe patterns, comprising:

a memory unit for storing basic patterns for wavefronts of lights from objects;

a motion detection unit for detecting a motion vector of each object to be displayed after a prescribed time;

a classification unit for classifying the objects into a plurality of groups according to motions of the objects indicated by the motion vector of each object, such that objects in an identical motion are classified as belonging to an identical group;

a calculation unit for calculating a hologram fringe pattern for each classified group of objects separately by initially using a corresponding one of the basic patterns and subsequently image processing each calculated hologram fringe pattern; and

a hologram production unit for producing a hologram to be displayed after the prescribed time by synthesizing all separately calculated hologram fringe patterns.

5. The system of claim 4, wherein the calculation unit calculates the hologram fringe pattern by carrying out one or both of a translation processing and a rotation processing on the corresponding one of the basic patterns.

6. The system of claim 4, wherein the calculation unit calculates the hologram fringe pattern for only those groups of objects which are moving according to the motion vector of each object, and the hologram production unit produces the hologram by synthesizing all separately calculated hologram fringe patterns with original hologram fringe patterns for objects which are not in motion.