Color Halftone Processing Using Dynamic NPac Vector Selection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing color mapping techniques in imaging systems often fail to provide desired color properties across the entire color space, leading to suboptimal results in halftone color separations, especially when transitioning between different color spaces.

Innovation Solution

A method is introduced to generate custom color mappings by accessing multiple color mappings that convert color values into Neugebauer Primary area coverage (NPac) vectors, comparing imaging metrics for these vectors, and selecting the optimal NPac vector for improved color properties, such as reduced ink use and enhanced color gamut.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a single color mapping is used for halftone processing, then the processing is simple and fast, but the color properties are suboptimal across the whole color space

Engineering Contradiction:
Improvecolor property accuracyVSAvoidcolor mapping complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent divides the color space into multiple regions, each with its own optimized color mapping. Instead of using a single color mapping for the entire color space, the system segments the color space and applies different mappings to different segments, thereby improving color property accuracy across the whole range while managing complexity through localized optimizations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a dynamic color mapping selection mechanism that adapts the color mapping based on the input color values. The system dynamically determines which color mapping to apply by evaluating the characteristics of the input color and selecting the most appropriate mapping from multiple available mappings, allowing optimal color properties to be achieved across different regions of the color space.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If multiple color mappings are evaluated for each color value, then optimal color properties are achieved, but the processing time increases

Engineering Contradiction:
Improvecolor property optimizationVSAvoidprocessing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent pre-evaluates and stores multiple color mappings during an offline preparation phase, organizing them in a structure that enables efficient runtime selection. By performing the computationally intensive evaluation of multiple mappings in advance and storing the results in an optimized data structure, the system reduces the processing time required during actual halftone operations while maintaining the ability to select optimal mappings.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses a lightweight data structure to store pre-computed color mapping information that can be quickly accessed and discarded. The system employs an efficient representation of color mapping data that minimizes memory usage and access time, allowing rapid selection and application of mappings without requiring complex or long-lived data structures, thereby reducing processing overhead.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP3135025B1Color halftone processing
Publication Date: 2020.09.02 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3135025B1 patent drawingFigure 1~2
  • EP3135025B1 patent drawingFigure 3~4
  • EP3135025B1 patent drawingFigure 5

AI summary

A method of color halftone processing is disclosed. A plurality of color mappings each provide a mapping from a color value in a color space to a set of Neugebauer Primary area coverage (NPac) values in an NPac space. An imaging metric is obtained for each NPac value in the set. An NPac value in the set is selected based on the imaging metric. The selected NPac value is used as an output NPac value in a combined color mapping for the color value.