Halftone Edge Pixel Dot Addition for Image Smoothness
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Solution Overview
Problem
Halftone image forming technologies face challenges in producing smooth edges due to the binary nature of dot representation, where images with high detail struggle with smooth printing and those with low detail struggle with clarity.
Innovation Solution
A halftone revision apparatus and method that detects edge pixels in an image and adds dots based on the number of adjacent white pixels, using a filtering pattern and control unit to determine whether to add dots or adjust pixel values, with reference values set according to pixel density and edge direction, improving edge smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If halftoning is applied to convert multi-level images to binary dot representation, then image formation is enabled, but edge smoothness deteriorates
Solution Approach 1:
The patent applies preliminary action by detecting edge pixels before the halftoning process and pre-calculating the number of adjacent white pixels. This preliminary detection allows the system to prepare special handling for edge areas, enabling smoother edges to be achieved during the subsequent dot addition phase without compromising the overall binary image formation.
Solution Approach 2:
The patent implements local quality by differentiating the processing approach for edge pixels versus non-edge pixels. Edge pixels receive special treatment where dots are added based on the count of adjacent white pixels, while regular pixels follow standard halftoning. This localized differentiation resolves the contradiction by applying enhanced smoothness only where needed (at edges) while maintaining efficient binary representation elsewhere.
2Measurement precision
If AM screen with high LPI is used to improve detail, then printing detail is improved, but smooth printing deteriorates
Solution Approach 1:
The patent applies dynamics by making the dot addition process adaptive rather than fixed. The system dynamically determines whether to add dots to edge pixels based on the calculated number of adjacent white pixels and compares it against reference values. This dynamic adjustment allows the system to optimize between detail and smoothness for each specific edge case, resolving the contradiction between high LPI detail capability and smooth printing.
3Ease of operation
If AM screen with low LPI is used to improve smooth printing, then smooth printing is improved, but printing detail deteriorates
Solution Approach 1:
The patent implements parameter changes by adjusting the reference values used in dot addition decisions based on the specific characteristics of each edge pixel, such as the number of adjacent white pixels and the edge direction. This parameter adaptation allows the system to optimize the balance between smoothness and detail for different printing conditions, resolving the contradiction between low LPI smooth printing and high detail requirements.
Data Source
AI summary
A halftone revision apparatus includes a screening unit to screen an input image, and a revision unit to detect edge pixels in the input image, and to add a dot to a detected edge pixel according to a number of white pixels adjacent to the detected edge pixel. Therefore, edges in the halftoned image can be improved.