Image Processing Sharpness Recovery Filter for Electrophotographic Line Width Correction
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Solution Overview
Problem
Conventional image processing methods for electrophotographic image forming apparatuses face challenges in improving sharpness, particularly for images with complex shapes, due to high processing loads and inaccurate line width control, leading to issues like thinning and crushing of lines.
Innovation Solution
An image processing apparatus that generates a sharpness recovery amount using a spatial frequency response filter and performs line width correction based on this data, correcting pixel values and exposure position information to enhance image sharpness with reduced processing load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional line width correction techniques are applied to improve sharpness, then sharpness of output image is improved, but processing load becomes heavy
Solution Approach 1:
The patent extracts only the essential information needed for line width correction by detecting edge portions and their directions, rather than performing comprehensive line width detection on entire images. This selective extraction approach maintains sharpness improvement while significantly reducing processing load.
Solution Approach 2:
The image processing is segmented into distinct stages: edge portion detection, edge direction determination, and line width correction. By dividing the processing into separate functional blocks (detection unit, determination unit, correction unit), the system can apply corrections only where needed rather than processing entire images uniformly.
2Manufacturing precision
If conventional line width correction techniques are applied to complex-shaped images, then sharpness improvement is attempted, but line width is not controlled appropriately due to erroneous extraction
Solution Approach 1:
The patent dynamically adjusts the line width correction amount based on the detected edge direction. By determining edge directions in main scanning and sub scanning directions separately and applying appropriate correction amounts for each direction, the system adapts to complex shapes and prevents erroneous correction that would occur with static, uniform correction approaches.
Solution Approach 2:
Different correction strategies are applied to different regions of the image based on local edge characteristics. The detection unit identifies specific edge portions and their directions, and the correction unit applies targeted line width control only to these identified regions, ensuring appropriate handling of complex shapes without erroneous processing of entire images.
Data Source
AI summary
The image processing apparatus of the present invention includes: a generation unit configured to generate a sharpness recovery amount for recovering degradation of a spatial frequency response from a target image; and a line width correction unit configured to perform line width correction processing for the target image based on the sharpness recovery amount, and the line width correction unit corrects a line width in accordance with a sign of a pixel whose absolute value of the sharpness recovery amount is large in a case where signs of the sharpness recovery amounts reverse between adjacent pixels of the target image.