Halftoning Templates for 1200 dpi Text Rendering

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Solution Overview

Problem

Current digital printing technologies face limitations in achieving high resolution for non-saturated colored text and lines, as they are constrained by predefined image screens and cannot effectively utilize higher resolution capabilities without significant interface changes, leading to sub-optimal image rendering.

Innovation Solution

The use of templates that represent 4x4 regions of binary pixels, indexed by an 8-bit contone video value, allowing for 2-bit control of each pixel to achieve 1200 dpi resolution, enabling better rendering of non-saturated colored text and lines by allowing partial saturation and preventing aliasing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If predefined image screens are used for halftoning, then device complexity is reduced and ease of operation is improved, but manufacturing precision and measurement precision deteriorate due to inability to achieve true 1200 dpi resolution

Engineering Contradiction:
Improveresolution precisionVSAvoidinterface complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the 600 dpi pixel into a 4x4 array of 1200 dpi sub-pixels. Each pixel position in the logical 600 dpi image is divided into 16 physical sub-pixels at 1200 dpi resolution. This segmentation allows the system to achieve true 1200 dpi manufacturing precision while maintaining the simplicity of the 600 dpi interface, as the segmentation is handled automatically by the halftoning algorithm without requiring complex interface changes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary halftoning process that acts as a mediator between the simple 600 dpi interface and the complex 1200 dpi output. The intermediary algorithm processes the 600 dpi input data and generates the 1200 dpi patterned encoded halftone output, bridging the gap without requiring complex interface modifications. This intermediary layer handles the complexity internally while preserving interface simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If 600 dpi interface is maintained without significant changes, then ease of operation is improved, but manufacturing precision deteriorates due to inability to render non-saturated colored text and lines at 1200 dpi

Engineering Contradiction:
Improveedge resolutionVSAvoidinterface simplicity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent changes the parameter representation by using patterned encoded halftone values instead of traditional contone values. Each pixel position contains encoded pattern information that specifies which sub-pixels within the 4x4 array should be activated. This parameter transformation enables precise control of individual 1200 dpi sub-pixels while maintaining compatibility with the existing 600 dpi interface structure, achieving high edge resolution without complicating the interface.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent adds a spatial dimension by expanding each 600 dpi pixel into a 4x4 grid of 1200 dpi sub-pixels. This dimensional expansion allows non-saturated colored text and lines to be rendered with true 1200 dpi precision by selectively activating sub-pixels within each pixel position. The dimensionality change is transparent to the interface, maintaining ease of operation while achieving superior manufacturing precision.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If traditional halftoning methods are used, then device complexity is reduced, but measurement precision deteriorates due to aliasing effects in rendered images

Engineering Contradiction:
Improveimage rendering accuracyVSAvoidhalftoning algorithm complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-defining a library of halftone patterns that are optimized for different gray levels and color saturations. Instead of computing halftone patterns in real-time, the system selects from pre-computed patterns based on the input pixel values. This preliminary preparation eliminates aliasing effects by using mathematically optimized patterns while reducing the complexity of the real-time processing algorithm.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses copying by replicating and adapting standard halftone patterns for different applications and resolutions. Rather than developing entirely new algorithms for 1200 dpi, the system copies and scales proven halftoning techniques from 600 dpi, adapting them to the higher resolution context. This approach maintains measurement precision by using validated patterns while controlling algorithm complexity through reuse of established methods.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP2718873B1Halftoning method and apparatus
Publication Date: 2018.10.10 ELECTRONICS FOR IMAGING INC
  • EP2718873B1 patent drawingFigure 1~2
  • EP2718873B1 patent drawingFigure 3~4
  • EP2718873B1 patent drawingFigure 5

AI summary

Techniques are provided that use one or more templates to improve the printing of non-saturated colored text and lines. Such templates are predetermined, fixed patterns which can be indexed or looked up via a code word with a fewer number of bits than in the corresponding template. Thus, such templates are used to increase the resolution or effective resolution of a display. In an embodiment, each template location represents a 4 x 4 region of binary pixels. The number of possibilities of template values is 2?(4*4) or 65,536. However, in accordance with an embodiment, only 256 of these 65,536 templates are available and are indexed by an 8 bit contone video value.