Error Diffusion Sequence for Curved Surface Printing
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Solution Overview
Problem
Existing error diffusion algorithms are ineffective for sparse images, particularly when printing on curved surfaces, as they fail to accurately simulate continuous-tone images due to non-printing pixels disrupting the geometric relationships between intended print locations.
Innovation Solution
The method involves selecting an error diffusion sequence based on the geometric relationships between intended print locations, using diffusion-weight relationships to propagate errors, and switching between different sets of diffusion-weight relationships according to the path changes, ensuring optimal print quality by approximating nearest neighbor print locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If standard error diffusion algorithms are used on sparse images, then processing is simpler, but print quality deteriorates due to disrupted geometric relationships
Solution Approach 1:
The patent segments the error diffusion process into two distinct sequences: a first sequence based on continuous-tone image pixel positions, and a second sequence based on actual intended print location positions. This segmentation allows each sequence to be optimized independently, resolving the contradiction between processing simplicity and print quality by handling the geometric disruption caused by sparse pixels.
Solution Approach 2:
The patent introduces an intermediary mapping relationship between the first sequence (image pixels) and the second sequence (print locations). This intermediary layer accounts for the geometric transformations and non-printing pixels, allowing error diffusion to maintain accuracy despite the sparse nature of the image data.
2Productivity
If error diffusion follows image pixel sequence, then processing is straightforward, but print artefacts increase on curved surfaces
Solution Approach 1:
The patent makes the error diffusion sequence dynamic by adapting it to the geometry of the print surface. Instead of a fixed image pixel sequence, the second sequence is generated based on the actual three-dimensional positions of print locations, allowing the processing to adapt to curved surfaces and reduce artefacts while maintaining efficiency.
3Adaptability or versatility
If non-printing pixels are included in the image, then curved surface printing is enabled, but geometric relationships between print locations are disrupted
Solution Approach 1:
The patent extracts the geometric relationship information from the continuous-tone image and separates it into a distinct second sequence based on intended print locations. This extraction allows the error diffusion process to account for non-printing pixels and curved surface geometry without being disrupted by them, maintaining precision while enabling versatility.
Data Source
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AI summary
A method of screening a continuous-tone image to produce an output image to be printed on a surface, wherein the continuous-tone image comprises a plurality of pixels having respective corresponding intended print locations; the method comprising the steps of: selecting a first sequence comprising a subset of the plurality of intended print locations, the first sequence being selected based on properties of the plurality of intended print locations; for each intended print location in the first sequence, identifying the corresponding pixel in the continuous-tone image to obtain a second sequence for an error diffusion process comprising the identified corresponding pixels in the continuous-tone image.