Halftone Processing Edge Resolution Preservation

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Solution Overview

Problem

Existing halftone processing methods fail to effectively preserve the resolution of images, particularly when dealing with cells containing edges or thin lines, leading to blurred edges and dropped resolution due to inappropriate barycentric position calculation and averaging of pixel values.

Innovation Solution

A halftone processing method that includes a detection unit for identifying specific pixel values and a determination unit to arrange print pixels based on the total value of pixel groups within each cell, ensuring accurate output values and preserving edge resolution by using attribute generation, density information conversion, and output determination processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If barycentric position calculation is used to determine dot positions in each cell, then pseudo gradations can be expressed, but edge resolution deteriorates and dots shift to inappropriate positions when cells contain multiple edges or thin lines

Engineering Contradiction:
Improvehalftone processing capabilityVSAvoidedge resolution
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The image is divided into multiple cells, and each cell is processed independently to determine dot positions. This segmentation allows the algorithm to handle local variations in edge density and avoid global barycentric shifts that blur edges.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different processing strategies are applied based on local cell characteristics. Cells containing edges or thin lines are identified and processed differently from uniform areas, preserving edge sharpness while maintaining halftone quality in other regions.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If average pixel values are output for units with halftone pixels, then processing is simplified, but edge detection fails and resolution drops

Engineering Contradiction:
Improveprocessing simplicityVSAvoidresolution
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

Edge detection is performed as a preliminary step before halftone processing. By identifying edges in advance, the algorithm can preserve them during the averaging and dot placement processes, preventing resolution loss while maintaining processing efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

An edge detection mechanism acts as an intermediary between the input image and the halftone processing. This intermediary identifies critical features that must be preserved, allowing the subsequent averaging process to exclude or specially handle edge regions.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If all pixels in a cell are averaged to determine output values, then processing is straightforward, but density variations increase and edge sharpness is lost

Engineering Contradiction:
Improveprocessing algorithmVSAvoiddensity uniformity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

Different weighting schemes are applied to different pixels within each cell based on their local characteristics. Pixels near edges receive different treatment than pixels in uniform regions, reducing density variations and preserving edge sharpness while maintaining algorithmic simplicity.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS9147140B2Image processing apparatus, method, and product for converting image data into fewer gradations based on total value of pixels in a group except for a detected pixel having a specific value
Publication Date: 2015.09.29 CANON KK
  • US9147140B2 patent drawing
  • US9147140B2 patent drawing
  • US9147140B2 patent drawing

AI summary

An image processing apparatus capable of converting input image data into image data expressing a dot pattern cell by cell includes a detection unit configured to detect a pixel having a specific pixel value in the input image data, and a determination unit configured to determine an output value of a pixel included in each cell by arranging as many print pixels as a number of print pixels according to a total value of pixel values of a pixel group including pixels included in a cell except the pixel detected by the detection unit on any of the pixels in the pixel group cell by cell.