Halftone Image Post-Processing via Lookup Tables

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Solution Overview

Problem

Current imaging systems face challenges in effectively post-processing halftone images to improve ink usage, robustness, and colorimetric accuracy without requiring specialized hardware, particularly in converting color representations between different color spaces for optimal halftone output.

Innovation Solution

The method involves post-processing halftone images by segmenting them into cells or windows, predicting colorimetric values, and replacing original cells or windows with optimized ones based on pre-determined metrics, using area coverage representations like Neugebauer Primary area coverage (NPac) vectors to control spatial distribution of colorants, and employing pre-computed lookup tables for efficient color mapping and halftoning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If advanced halftone area separation pipelines are used to improve ink usage and colorimetric accuracy, then manufacturing precision and reliability are improved, but device complexity increases due to specialized hardware requirements

Engineering Contradiction:
Improvecolorimetric accuracyVSAvoidhardware complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent creates a software-based copy of the advanced halftone processing functionality that normally requires specialized hardware. By implementing a lookup table system that stores pre-computed halftoning data, the system replicates the behavior of complex hardware pipelines through software lookup and interpolation operations, achieving similar colorimetric accuracy without the specialized hardware infrastructure

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent performs halftoning calculations in advance and stores the results in lookup tables. By pre-computing the halftone transformations for various color values and storing them for quick retrieval, the system eliminates the need for complex real-time hardware processing, achieving both high precision and computational efficiency

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If sophisticated color mapping and halftoning processes are implemented to improve imaging quality, then manufacturing precision is improved, but ease of manufacture deteriorates due to increased processing complexity

Engineering Contradiction:
Improveimaging qualityVSAvoidprocessing simplicity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent pre-computes complex color mapping and halftoning transformations during system initialization or offline processing, storing the results in lookup tables. This preliminary action converts difficult real-time computational problems into simple table lookup operations, maintaining high imaging quality while dramatically simplifying the runtime processing requirements

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent divides the continuous color space into discrete segments or bins, with each bin representing a range of similar colors. By segmenting the color space and pre-computing representative halftone values for each segment, the system simplifies the manufacturing process while maintaining acceptable imaging quality across the entire color gamut

Inventive Principle:
Principle #1Segmentation

3Productivity

If real-time colorimetric prediction and optimization are performed to improve ink usage efficiency, then productivity is improved, but device complexity increases due to computational requirements

Engineering Contradiction:
Improveink usage efficiencyVSAvoidcomputational complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent pre-computes ink usage optimization data and stores it in lookup tables indexed by colorimetric values. By performing the computationally intensive optimization calculations in advance, the system enables rapid real-time ink usage decisions through simple table lookups, achieving both high productivity and ink efficiency without excessive computational complexity during operation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces complex real-time computational mechanics with a lookup table-based retrieval system. Instead of performing sophisticated colorimetric predictions and optimizations in real-time through complex algorithms, the system substitutes these mechanical computational processes with pre-computed data retrieval and interpolation operations, reducing computational complexity while maintaining productivity

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

Data Source

PatentEP3213499B1Post-processing halftone images
Publication Date: 2020.01.22 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3213499B1 patent drawingFigure 1A~1B
  • EP3213499B1 patent drawingFigure 1C~2
  • EP3213499B1 patent drawingFigure 3

AI summary

Systems and methods for replacing cells of an image based on some pre- determined metric are described herein. For example, systems and methods described herein may improve the functioning of a standard imaging system For example, the systems and methods described herein may be used to post- process existing images in an imaging system based on one or more pre- determined metrics and improve the halftone images according to those pre- determined metrics.