LDPC-Coded Holographic Data Pages for Pixel Misalignment Errors
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Solution Overview
Problem
Holographic optical information processing systems face high bit error rates due to misalignment between data pixels and detector pixels, which are not effectively addressed by existing error correction codes.
Innovation Solution
An optical information processing apparatus that uses a low density parity check code, where data is encoded and mapped into a data page with a mark at the center and subblocks, allowing for improved error correction by calculating reproduction probabilities and decoding using a spatial light modulator and detector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional error correction codes are used in holographic optical information processing, then the system can perform parallel signal processing faster than bit-by-bit storage, but the bit error rate becomes unacceptably high due to pixel misalignment between data page and detector
Solution Approach 1:
The patent divides the data page into multiple blocks, where each block contains data pixels and corresponding check pixels. This segmentation allows independent error correction for each block, enabling the system to maintain high parallel processing speed while effectively correcting errors caused by pixel misalignment through localized parity check operations
Solution Approach 2:
The patent introduces check pixels as intermediary elements that mediate between the data pixels and the detection process. These check pixels contain parity information that enables error detection and correction, serving as a bridge that resolves the conflict between fast parallel processing and reliable error-free data retrieval
2Adaptability or versatility
If the optical information recording medium contracts or misaligns, then the system maintains its holographic parallel processing capability, but the detected data page contains errors due to pixel mismatch
Solution Approach 1:
The patent performs preliminary error correction preparation by embedding check pixels with parity information into the data page before detection. This preliminary action enables the system to maintain its holographic parallel processing adaptability while being prepared to correct any alignment errors that may occur during detection, without requiring post-detection realignment
Solution Approach 2:
The patent implements a feedback mechanism where check pixels provide parity information that feeds back into the error correction process. This feedback allows the system to detect and correct pixel misalignment errors automatically, maintaining both the adaptability of holographic parallel processing and the precision of data retrieval despite physical variations in the recording medium
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 minimizes decoding failure rates by distributing error information evenly, enhancing the accuracy of pixel alignment and overall decoding performance.
Implementation Method 1
An optical information processing apparatus using the holography performs recording operation by projecting an information beam, which contains an image information of data to record, and a reference beam, which is to be interfered with the information beam
Implementation Method 2
for reproducing, the reference beam is projected to the optical information recording medium, a reproduced beam, which is diffracted from the recording medium, is detected
Data Source
AI summary
An apparatus and method for processing optical information using a low density parity check code are suggested. An optical information recording method includes the steps of encoding data to record into a low density parity check code; representing the data, which is encoded into the low density parity check code, to a spatial light modulator in the unit of a data page; and modulating a recording beam into the data page representing the spatial light modulator to be recorded in the form of hologram in a recording medium. By blocking inexact probability information from being concentrated in the LDPC code block, by achieving exact probability information through effective allocation of a mark, and by improving average accuracy of the pixel, which corresponds to the LDPC code, failure rate of decoding can be minimized so that decoding performance can be improved.