Image Processing Apparatus Dot Thinning for Toner Reduction
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Solution Overview
Problem
Conventional image processing apparatuses face challenges in reducing recording agent consumption while maintaining image quality, especially in character portions, due to inaccurate region determination between character and photographic images, leading to decreased legibility and tone reversal.
Innovation Solution
An image processing apparatus and method that determines whether a pixel is part of a region with a predetermined number of lines, applying a uniform reduction rate to edge and non-edge pixels in dense regions, and higher reduction rates to non-edge pixels in sparse regions, and corrects black pixels to white in binary images based on region density, to optimize toner consumption without compromising image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If dot thinning processing is executed for the entirety of image data in recording agent saving mode, then the amount of consumption of recording agent is reduced, but the density of the whole image becomes lower and printing quality decreases
Solution Approach 1:
The patent applies different processing strategies to different regions of the image: character regions undergo dot thinning with edge enhancement to maintain legibility, while photograph regions use uniform dot thinning. This local differentiation allows recording agent reduction without compromising overall printing quality.
Solution Approach 2:
The image data is segmented into character portions and photograph portions through region determination processing. This segmentation enables application of appropriate dot thinning strategies to each portion, reducing recording agent consumption while maintaining the quality characteristics needed for each region type.
2Manufacturing precision
If edge portion deletion rate is made lower than non-edge portion in character region, then character legibility is maintained, but processing complexity increases
Solution Approach 1:
Within character regions, the patent applies different deletion rates to edge portions versus non-edge portions. Edge portions use a lower deletion rate to preserve character outlines and legibility, while non-edge portions use higher deletion rates for greater recording agent reduction.
Solution Approach 2:
The system performs region determination processing in advance to identify character regions and their edge portions before applying dot thinning. This preliminary classification enables the subsequent differential deletion rate application without requiring complex real-time processing during the thinning operation.
3Adaptability or versatility
If region determination is performed based on image feature amount analysis, then character and photograph regions can be identified, but determination precision decreases and erroneous determination occurs
Solution Approach 1:
The patent employs multiple determination methods with different parameters (edge detection algorithms, density threshold analysis, line pattern recognition) and switches between them based on the specific image characteristics. This multi-parameter approach improves determination precision while maintaining adaptability to different image types.
Data Source
AI summary
Whether a pixel in an image is included in a region with at least a predetermined number of lines is determined; with regard to a pixel that is determined to be included in the region with at least the predetermined number of lines, a pixel value is reduced at the same reduction rate whether the pixel is an edge portion or a non-edge portion, and with regard to a pixel that is determined to be included in a region in which the number of lines is smaller than the predetermined number, a pixel value is reduced in such a manner that a reduction rate is higher when the pixel is the non-edge portion than when the pixel is the edge portion.