Complex-Value Signal Encoding for 3D Hologram Reconstruction

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Solution Overview

Problem

Conventional methods for encoding complex-valued signals into phase-modulating optical elements for holographic 3D imaging are inefficient, requiring numerous iteration steps and high computational effort, leading to reduced diffraction efficiency and increased noise due to the limitations of spatial light modulators in providing independent amplitude and phase modulation.

Innovation Solution

A method utilizing a transformation algorithm to encode complex-valued signals by calculating a two-dimensional distribution of complex values in a periodicity interval, allowing for iterative optimization with reduced iteration steps and improved diffraction efficiency, using a phase-modulating optical element like a spatial light modulator, and adapting amplitude boundary conditions and signal range parameters for rapid convergence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional encoding methods are used to encode complex-valued signals into phase-modulating optical elements, then the hologram can be reconstructed, but the number of iteration steps is large and computational effort is high

Engineering Contradiction:
Improvereconstruction qualityVSAvoidnumber of iteration steps
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing amplitude boundary conditions from the statistical distribution of the complex-valued signal before the iterative encoding process begins. This pre-computed information guides the iteration algorithm, enabling it to converge to high-quality reconstruction with fewer iteration steps, thus reducing computational time while maintaining manufacturing precision

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by using the statistical distribution characteristics of the complex-valued signal to dynamically adjust amplitude boundary conditions during the iterative process. The algorithm continuously monitors the reconstruction quality and adjusts parameters based on the signal's statistical properties, creating a closed-loop system that accelerates convergence while ensuring high reconstruction quality

Inventive Principle:
Principle #23Feedback

2Reliability

If conventional encoding methods are used with spatial light modulators, then the hologram can be encoded, but diffraction efficiency is reduced and noise is increased

Engineering Contradiction:
Improvediffraction efficiencyVSAvoidnoise
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by modifying the amplitude boundary conditions based on the statistical distribution of the complex-valued signal. By adjusting these parameters to match the signal's characteristics, the encoding process achieves higher diffraction efficiency and suppresses noise generation, directly improving reliability while reducing harmful effects

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses partial action by focusing the iterative optimization only on the necessary parameters (amplitude boundary conditions derived from statistical distribution) rather than optimizing all parameters. This selective approach achieves sufficient reconstruction quality with reduced computational effort, thereby improving diffraction efficiency and reducing noise without requiring excessive computation

Inventive Principle:
Principle #16Partial or excessive action

3Manufacturing precision

If iterative calculation is performed to achieve high reconstruction quality, then the hologram accuracy is improved, but computational effort increases

Engineering Contradiction:
Improvereconstruction qualityVSAvoidencoding speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies preliminary action by pre-computing the statistical distribution characteristics and amplitude boundary conditions before the iterative encoding process. This preparation work enables the iteration algorithm to converge faster with fewer steps, thereby maintaining high reconstruction quality while significantly improving encoding speed and productivity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent substitutes the conventional mechanical iterative optimization process with a statistically-guided algorithm that uses pre-computed distribution characteristics. This replacement reduces the number of iterative steps required, thereby maintaining manufacturing precision while improving productivity through more efficient computational mechanics

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 significantly reduces the number of iteration steps required for achieving high reconstruction quality, enhances diffraction efficiency, and enables real-time encoding of holograms for holographic 3D displays by optimizing the transformation algorithm and signal processing.

Implementation Method 1

Computer-generated holograms (CGH) are based on the principle of diffraction of a sufficiently coherent electromagnetic wave at the diffracting structures of the CGH

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

a phase-modulating optical element for the reconstruction of a three-dimensional object

Methodology Applied
Scientific EffectPhase modulation: Phase Modulation

Data Source

PatentUS20240134313A1Method and device for encoding complex-value signals for the reconstruction of three-dimensional objects
Publication Date: 2024.04.25 SEEREAL TECHNOLOGIES SA
  • US20240134313A1 patent drawing
  • US20240134313A1 patent drawing
  • US20240134313A1 patent drawing

AI summary

A method for encoding complex-valued signals of a computer-generated hologram into a phase-modulating optical element for the reconstruction of a three-dimensional object, and to a computer program product for encoding complex-valued signals of a computer-generated hologram, and to a holographic display for the reconstruction of a three-dimensional object. The object is to reduce the effort on encoding a complex-valued spatial distribution by an iteration method on the basis of phase encoding, so that the computer-generated hologram resulting therefrom can be represented more rapidly and with the same or an improved reconstruction quality. In particular, the convergence during the iterative optimization is intended to be accelerated. This is achieved by a method in which degrees of freedom of the hologram plane as well as the reconstruction plane are used for optimizing the iteration method for rapid convergence and maximization of the diffraction efficiency in the signal range.