Phase-Invariant Codewords for Partial Halftone Data Recovery

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Solution Overview

Problem

Existing methods for encoding data in halftone images require capturing the entire data-bearing medium to recover information, which is inefficient and limits the use of devices with smaller fields of view.

Innovation Solution

A method that encodes data using a structured array of bits with circular shifts, allowing data recovery from a portion of the medium without capturing the entire array, using phase-invariant codewords and a lookup table to decode the message from a subset of the image.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the entire data-bearing medium is captured to recover information, then complete data recovery is achieved, but the device size and complexity increase

Engineering Contradiction:
Improvedata recovery completenessVSAvoidcapture device size
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The data-bearing medium is divided into multiple regions, each containing a complete codeword through circular shifting. This segmentation allows any single region to be independently decoded to recover the complete message, eliminating the need to capture the entire medium.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention enables data recovery from only a portion of the data-bearing medium rather than requiring the entire medium to be captured. By using phase-invariant codewords with circular shifts, the system allows partial capture while still achieving complete data recovery.

Inventive Principle:
Principle #16Partial or excessive action

2Manufacturing precision

If traditional halftone encoding is used, then image quality is maintained, but data recovery requires the entire image

Engineering Contradiction:
Improvehalftone image qualityVSAvoiddata recovery efficiency
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The halftone image is segmented into regions that each contain redundant codeword information through circular shifts. This allows the data to be recovered from any single region without requiring processing of the entire image, improving recovery efficiency while maintaining image quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The codewords are pre-processed with circular shifts before being embedded in the halftone image. This preliminary action ensures that each region contains complete decodable information, allowing rapid data recovery without needing to process the entire image.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If circular shifts with phase-invariant codewords are used, then data can be recovered from a portion of the medium, but the encoding complexity increases

Engineering Contradiction:
Improvedata recovery accessibilityVSAvoidencoding complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The encoding process uses periodic circular shifts of codewords across different regions of the image. This periodic pattern simplifies the encoding implementation while ensuring that each region contains complete decodable information, making data recovery accessible from any portion of the medium.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3047353B1Data-bearing medium
Publication Date: 2020.04.08 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3047353B1 patent drawingFigure 1
  • EP3047353B1 patent drawingFigure 2A~2B
  • EP3047353B1 patent drawingFigure 3

AI summary

An example method for forming a data-bearing medium in accordance with aspects of the present disclosure includes setting variables associated with the data- bearing medium, the variables comprising a bit length of a codeword, identifying a phase-invariant codeword based on the variables, and arranging rows of the data- bearing medium with the phase-invariant codewords.