Image Processing Apparatus Edge Screen Processing

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Solution Overview

Problem

Existing image processing techniques, particularly those using halftone screen processing, often result in jaggy edges in binary printers, leading to unintended solid outlines for objects of intermediate colors and inefficiencies in processing speed, especially in low-performance environments.

Innovation Solution

An image processing apparatus and method that utilize a combination of screen processing and edge screen processing, employing threshold matrices and logical OR operations to differentiate between edge and non-edge pixels, allowing for reduced jaggy artifacts and improved reproducibility of object shapes, even in binary printers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If halftone screen processing is applied to binary printers, then tone representation is achieved, but jaggy edges and solid uniform outlines occur

Engineering Contradiction:
Improvetone representation capabilityVSAvoidedge smoothness
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The image processing is segmented into two distinct pathways: regular screen processing for non-edge areas and edge screen processing for edge portions. This segmentation allows each pathway to be optimized independently - regular processing maintains tone representation while edge processing specifically addresses jaggy artifacts through enhanced anti-aliasing techniques

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different processing qualities are applied to different regions of the image. Edge portions receive enhanced processing with higher anti-aliasing quality to eliminate jaggy artifacts, while non-edge areas use standard screen processing to maintain overall tone representation. This local quality differentiation resolves the contradiction by applying appropriate processing intensity where needed

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If complex dot output determination processing is applied to reduce jaggy, then edge quality improves, but processing speed decreases

Engineering Contradiction:
Improveedge qualityVSAvoidprocessing speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The complex processing is segmented and applied only where necessary - specifically to edge portions detected through gradient analysis. Non-edge areas bypass the complex dot output determination and proceed directly to rendering, significantly reducing overall processing time while maintaining edge quality

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of applying complex anti-aliasing processing to the entire image, the system applies enhanced processing only partially to detected edge regions. This partial action approach achieves sufficient edge quality improvement without the computational cost of processing the whole image at high quality

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2464092B1Image processing apparatus and image processing method
Publication Date: 2016.06.29 CANON KK
  • EP2464092B1 patent drawingFigure 1
  • EP2464092B1 patent drawingFigure 2
  • EP2464092B1 patent drawingFigure 3

AI summary

An image processing apparatus (300) comprises first screen processing means (304) configured to apply screen processing to image data using a first threshold matrix, second screen processing means (307) configured to apply screen processing to the image data using a second threshold matrix, and edge detection means (305) configured to detect an edge portion of an object included in the image data. The image processing apparatus also comprises output means (309) configured to select and output image data obtained by a logical OR operation (308) between image data obtained by the first screen processing means and image data obtained by the second screen processing means for a pixel detected by the edge detection means as an edge portion, and select and output the image data obtained by the first screen processing means for a pixel other than the edge portion.