Image Processing Device Toner Peeling Correction
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Solution Overview
Problem
Toner peeling issues at folding positions in electrographic printed matter are not corrected in existing image processing apparatuses when scanning images, leading to defects in scanned document images.
Innovation Solution
An image processing apparatus is configured with a toner peeling detecting unit that identifies and corrects toner peeling parts on creases by analyzing density distributions and adjusting pixel values based on adjacent pixel values, using specific local gradation detection and crease detection units to accurately identify and remove toner peeling defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing image processing apparatus is used to scan printed matter, then scanning process is completed, but toner peeling parts on creases are not corrected leading to image defects
Solution Approach 1:
The image processing is divided into distinct functional units: crease detecting unit that identifies crease regions, toner peeling detecting unit that specifically detects toner peeling on those creases, and toner peeling correcting unit that repairs the defects. This segmentation allows targeted correction without reprocessing the entire image, improving reliability while managing complexity through modular design.
Solution Approach 2:
The system performs preliminary detection of creases and toner peeling parts before final image correction. By identifying problem areas in advance through density distribution analysis and comparing with adjacent pixel values, the system prepares correction data that is then applied to restore image quality, preventing defect propagation.
2Measurement precision
If multiple scans with different illumination angles are performed to detect creases, then detection accuracy improves, but processing time increases
Solution Approach 1:
Instead of requiring multiple full-image scans with different illumination angles, the system applies local analysis only to detected crease regions. The crease detecting unit identifies candidate areas using density distribution, and then toner peeling detection is performed locally on those specific regions by comparing pixel values with adjacent areas, achieving high precision without the time cost of multiple complete scans.
Solution Approach 2:
The system uses the scanned image data itself as a reference copy to detect toner peeling by comparing pixel values with adjacent pixels. This self-referential approach eliminates the need for additional reference scans or multiple illumination angle captures, maintaining measurement precision while significantly reducing processing time.
3Manufacturing precision
If automated toner peeling detection is implemented, then correction accuracy improves, but device complexity increases
Solution Approach 1:
The system detects toner peeling by monitoring changes in pixel density parameters and comparing them with adjacent pixel values. When a significant parameter change is detected at crease locations, it indicates toner peeling. This parameter-based automated detection achieves high correction accuracy through quantitative analysis while keeping the processing logic relatively simple through threshold-based decision making.
Data Source
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AI summary
A crease detecting unit 13 detects a crease in a document image. A toner peeling detecting unit (a) detects as a toner peeling part a pixel area on the crease, the pixel area (a1) having a width of the predetermined number of pixels in a direction perpendicular to the crease, (a2) having a background color, and (a3) of which both sides are adjacent to at least two pixels in a direction perpendicular to the crease, the at least two pixels having a color other than the back ground color, and (b) corrects a pixel value of the toner peeling part on the basis of pixel values of at least two pixels adjacent to both sides of the pixel area.