Computer-Generated Hologram Encoding Using Precomputed Lookup Tables

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Solution Overview

Problem

Current methods for generating computer-generated holograms (CGHs) face challenges in efficiently encoding complex data to produce high-quality, clear 3D images, particularly in ensuring that all light frequencies emitted from the spatial light modulator (SLM) reach the observer's eye lens, which affects image clarity and precision.

Innovation Solution

The method involves using a deep learning network to propagate and encode object data from an image plane to an SLM plane, assigning phase data based on light frequency, observer distance, and eye lens size to optimize light transmission, and iteratively refining the encoding process to minimize differences between input and output data, ensuring all light frequencies are properly directed and encoded.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional encoding methods are used to generate CGH, then the generation process is simpler, but the image clarity and precision deteriorate because not all light frequencies reach the observer's eye lens

Engineering Contradiction:
Improveimage clarityVSAvoidencoding process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing encoding tables for different light frequencies before actual CGH generation. The system pre-processes the encoding requirements for various frequencies and stores them in lookup tables, so that during runtime, the encoding can be performed by simple table retrieval rather than complex real-time calculation. This resolves the contradiction by preparing the encoding data in advance, improving image clarity while keeping the actual generation process simple.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary encoding table that acts as a mediator between the input image data and the final CGH output. Instead of directly encoding complex multi-frequency light data, the system uses pre-computed encoding tables that translate image data into appropriate holographic patterns for each frequency. This intermediary structure simplifies the encoding process while ensuring all frequency components are properly directed to reach the observer's eye lens.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If deep learning network is used to encode complex data, then the image quality and precision improve, but the computational time and processing complexity increase

Engineering Contradiction:
Improveencoding precisionVSAvoidcomputational time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-training the deep learning network offline and storing its learned encoding patterns in lookup tables. The complex computational work of learning optimal encoding strategies for different frequencies is performed in advance during network training, not during actual CGH generation. During runtime, the system only needs to retrieve pre-computed encoding values from the tables, dramatically reducing computational time while maintaining high encoding precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses copying by creating simplified representations of the complex deep learning encoding process in the form of lookup tables. Instead of executing the full deep learning network during CGH generation, the system copies the essential encoding patterns learned by the network into tabular form. This allows the system to replicate the high precision of deep learning encoding while avoiding its computational overhead during actual operation.

Inventive Principle:
Principle #26Copying

3Measurement precision

If iterative refinement process is applied to minimize data differences, then the encoding accuracy improves, but the processing duration increases

Engineering Contradiction:
Improveencoding accuracyVSAvoidprocessing duration
Core Design Contradiction:
Measurement precisionVSDuration of action of moving object

Solution Approach 1:

The patent applies preliminary action by pre-determining the optimal number of iterations and convergence criteria during system setup. The iterative refinement process is configured with predetermined parameters that prevent excessive iterations, allowing the system to achieve sufficient encoding accuracy without unnecessary processing time. The refinement process stops once a pre-established accuracy threshold is met, balancing precision and duration.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies partial action by performing iterative refinement only when necessary - specifically, only for frequency components that require correction to ensure they reach the observer's eye lens. Not all encoding operations require full iterative refinement; the system selectively applies refinement to specific frequency components or data portions that need it, reducing overall processing duration while maintaining necessary encoding accuracy.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS11740587B2Method and apparatus for generating computer-generated hologram
Publication Date: 2023.08.29 SAMSUNG ELECTRONICS CO LTD
  • US11740587B2 patent drawing
  • US11740587B2 patent drawing
  • US11740587B2 patent drawing

AI summary

Provided is a method of generating a computer-generated hologram (CGH), the method including obtaining complex data including amplitude data of object data and phase data of the object data corresponding to a spatial light modulator (SLM) plane by propagating the object data from an image plane to the SLM plane, encoding the complex data into encoded amplitude data, and generating a CGH based on the object data including the encoded amplitude data.