Image Variable Magnification Device Screen Pattern Deformation
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Solution Overview
Problem
Existing image variable magnification methods in electrophotographic processes suffer from image deformation and quality deterioration due to pixel insertion or deletion, particularly when correcting positional displacements and magnification irregularities, which complicates hardware pipeline processes and deforms screen patterns.
Innovation Solution
An image variable magnification device comprising a shift amount determining unit, first and second screen processing units, and a variable magnification processing unit that disperses pixel shifts and determines gradation values by applying dither thresholds to maintain screen pattern integrity during image enlargement or reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If variable magnification processing is carried out for the image obtained by screen processing by inserting or deleting pixels, then the image size is adjusted to correct positional displacement and magnification irregularity, but the screen pattern is deformed and image quality deteriorates
Solution Approach 1:
The patent applies preliminary screen processing to the original image at the same magnification ratio as the variable magnification processing before inserting or deleting pixels. This preliminary processing calculates the screen pattern at the target magnification, so when pixels are later inserted or deleted to achieve variable magnification, the screen pattern maintains its correct form without deformation. This resolves the contradiction by preparing the screen pattern in advance at the correct scale.
Solution Approach 2:
The patent performs preliminary screen processing on the original image at the same magnification ratio as the intended variable magnification processing before the actual pixel insertion/deletion. This preliminary action counteracts the potential screen pattern deformation that would occur if screen processing were applied after magnification, thereby preventing the harmful effect of screen form distortion while maintaining accurate image positioning.
2Measurement precision
If screen processing is applied after variable magnification processing, then the image can be processed at high resolution, but the screen pattern becomes deformed and consecutive pixel insertion occurs degrading image quality
Solution Approach 1:
The patent performs screen processing on the original image at the same magnification ratio as the intended variable magnification processing before the actual pixel insertion or deletion. This preliminary screen processing ensures that the screen pattern is calculated at the correct magnification from the start, preventing deformation. After this preliminary processing, variable magnification is applied by inserting or deleting pixels, and finally high-resolution processing is applied to maintain image quality without causing screen pattern deformation or consecutive pixel insertion issues.
3Length of moving object
If pixels are inserted in each interpolation period to enlarge the image, then the image is enlarged in the sub-scanning direction, but the screen pattern is deformed around the inserted pixels
Solution Approach 1:
The patent applies preliminary screen processing to the original image at the same magnification ratio as the intended enlargement processing before inserting pixels in each interpolation period. This preliminary processing calculates the screen pattern at the target magnification, so when pixels are subsequently inserted to enlarge the image, the screen pattern maintains its correct form without deformation around the inserted pixels, resolving the contradiction between image enlargement and screen pattern integrity.
Data Source
AI summary
Disclosed is an image variable magnification device including: a first screen processing unit to carry out a first screen processing for the original image by applying a dither threshold on a position in a dither threshold matrix, which corresponds to a position obtained by adding the shift amount; a second screen processing unit to carry out a second screen processing for the original image by applying a dither threshold on a position in the dither threshold matrix, which corresponds to a position obtained by adding the shift amount and +1 or −1; and a variable magnification processing unit to shift each pixel in an image obtained by the first screen processing, in accordance with the shift amount, and to determine a gradation value of a pixel required to be inserted due to the shift, by adopting a processing result obtained by the second screen processing unit.