Halftone Dot Image Processing Apparatus with Adaptive Smoothing
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Solution Overview
Problem
In offset printing, the reproduction of halftone dot shape and color tone is challenging when using image forming apparatuses that employ dot recording methods, as existing techniques like smoothing filters often blur the halftone dot shape, reducing reproducibility, especially when overlapping halftone dot images of different colors.
Innovation Solution
An image processing apparatus that performs multivalue conversion using a smoothing filter with varying degrees of blur based on color tone information, prioritizing color reproducibility in bright areas and halftone dot shape reproducibility in dark areas, to generate print data for halftone images with higher reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a smoothing filter is applied to perform multivalue conversion on halftone dot images, then color tone reproduction is improved, but halftone dot shape reproduction deteriorates due to blurring
Solution Approach 1:
The patent applies different smoothing filter degrees to different regions of the image based on local color tone characteristics. Bright regions use stronger smoothing to improve color reproduction, while dark regions use weaker smoothing to preserve halftone dot shapes. This local differentiation resolves the contradiction by optimizing each region according to its specific requirements rather than applying a uniform smoothing level across the entire image.
Solution Approach 2:
The patent dynamically adjusts the smoothing filter degree based on the color tone information of each pixel or region. The smoothing strength is not fixed but varies according to the brightness characteristics of different areas. This dynamic adaptation allows the system to automatically optimize the balance between color reproduction and shape preservation for each specific region, resolving the inherent contradiction between these two requirements.
2Measurement precision
If the smoothing filter degree is increased to improve color tone reproduction, then color fidelity is improved, but halftone dot shape becomes blurred
Solution Approach 1:
The patent implements region-specific smoothing where bright regions receive higher smoothing degrees for better color fidelity, while dark regions receive lower smoothing degrees to maintain sharp halftone dot shapes. This local quality differentiation allows the system to optimize color reproduction where needed without compromising shape clarity in regions where shape preservation is critical.
Solution Approach 2:
The patent changes the smoothing filter parameter (degree of smoothing) based on the brightness parameter of different image regions. By making the smoothing degree a variable parameter that adapts to local brightness conditions, the system achieves optimal color reproduction in bright areas while preserving shape clarity in dark areas, thus resolving the contradiction between these two opposing requirements.
3Ease of manufacture
If uniform multivalue conversion is applied to the entire image, then processing simplicity is maintained, but reproduction quality varies across different regions
Solution Approach 1:
The patent divides the image into different regions (bright and dark areas) and applies different multivalue conversion parameters to each region. This local quality approach ensures that each region receives the appropriate processing intensity, resulting in consistent high-quality reproduction across the entire image while maintaining reasonable processing complexity through automated region-based differentiation.
Solution Approach 2:
The patent employs dynamic parameter adjustment where the multivalue conversion settings automatically adapt to the local characteristics of each image region. This dynamic approach maintains processing efficiency through automated decision-making while achieving consistent reproduction quality across varying regions, resolving the contradiction between processing simplicity and reproduction quality consistency.
Data Source
AI summary
An image processing apparatus configured to generate print data used for recording image data expressing halftone dots by an image forming apparatus includes an input unit configured to input image data expressing halftone dots, an obtaining unit configured to obtain color tone information indicating color tone for each pixel or for each area including a plurality of pixels in the image data, a conversion unit configured to perform multivalue conversion of the image data based on a degree of smoothing according to the color tone information, a color separation processing unit configured to perform color separation on the image data which has been multi-valued by the conversion unit, and a halftone processing unit configured to convert image data which has been color-separated by the color separation processing unit into print data.