Hologram Generation via Spatio-Temporal Phase Correlation

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Solution Overview

Problem

Current digital hologram technologies face challenges in achieving high spatio-temporal correlation and large viewing angles due to limitations in pixel pitch size, making it difficult to manufacture spatial light modulators (SLMs) with small enough pixel pitches to provide extensive viewing angles.

Innovation Solution

A method for generating holograms by defining phase values for spatio-temporally identical pixels to ensure they have the same phase, increasing spatio-temporal correlation, and using these correlations to improve hologram compression rates through the generation of correlation images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the pixel pitch of the SLM is reduced to increase the viewing angle, then the viewing angle is improved, but the manufacturing difficulty increases significantly

Engineering Contradiction:

Improveviewing angleVSAvoidmanufacturing difficulty of SLM

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent divides the hologram generation into multiple viewpoints, with each viewpoint processed separately through the SLM. By segmenting the holographic content into discrete viewpoint images, the system achieves multi-view functionality without requiring a single SLM with extremely small pixel pitch, thus resolving the manufacturing difficulty while maintaining large viewing angle capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from spatial multiplexing (requiring small pixel pitch) to temporal multiplexing by displaying different viewpoint holograms at different time instances. This dimensional change from space to time allows achieving large viewing angles through sequential display rather than simultaneous spatial arrangement, avoiding the need for ultra-fine pixel pitch manufacturing

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If multiple SLMs are used to increase spatio-temporal reproduction space, then the hologram reproduction capability is improved, but the device complexity increases

Engineering Contradiction:

Improvespatio-temporal reproduction spaceVSAvoidnumber of SLMs

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent employs periodic temporal multiplexing where a single SLM sequentially displays multiple viewpoint holograms at different time instances. This periodic display approach achieves spatio-temporal hologram reproduction using one SLM instead of multiple SLMs, significantly reducing device complexity while maintaining the capability to reproduce multiple spatial and temporal holographic views

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The single SLM serves multiple functions by sequentially displaying different viewpoint holograms. Through temporal multiplexing, one SLM performs the work that would otherwise require multiple SLMs, making the system self-sufficient and eliminating the need for additional hardware components

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If random phase is applied to each pixel data independently, then the hologram generation flexibility is improved, but the spatio-temporal correlation between consecutive frames decreases

Engineering Contradiction:

Improvehologram generation flexibilityVSAvoidspatio-temporal correlation

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies different phase treatment strategies to different pixel groups: pixels representing the same 3D object point across different viewpoints receive correlated phase values to maintain spatio-temporal correlation, while other pixels maintain independent random phases for flexibility. This local differentiation resolves the contradiction between flexibility and correlation

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent pre-identifies corresponding pixel relationships across different viewpoints by mapping 3D object points to their 2D image projections. This preliminary establishment of pixel correspondence enables subsequent phase correlation to be applied systematically, ensuring spatio-temporal consistency while maintaining generation flexibility

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enhances the correlation between spatio-temporally continuous holograms, improving the viewing angle and compression efficiency by assigning the same phase values to identical pixels across viewpoints, thereby increasing the hologram's overall quality and compression rate.

Implementation Method 1

Holography is a technology that uses diffraction and interference of light

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 2

Holography is a technology that uses diffraction and interference of light

Methodology Applied

Scientific EffectInterference: Interference

Data Source

PatentUS11644792B2Method for generating hologram

Publication Date: 2023.05.09 ELECTRONICS & TELECOMM RES INST

AI summary

A method of generating a hologram includes receiving an input image representing a 3D object, defining a first phase value for a first pixel data such that spatio-temporally identical pixels with respect to the input image have the same phase, defining a second phase value for a second pixel data such that spatio-temporally identical pixels with respect to the input image have the same phase, and generating a multi-view hologram using the first phase value and the second phase value.