Image Forming Halftone Processing with Uncorrelated Pixel Groups
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image processing techniques for dot distribution in printing suffer from reduced image quality due to shifts in dot forming positions between groups, leading to visible unevenness and increased computation time for generating dither masks with blue and green noise characteristics.
Innovation Solution
An image forming device and method that utilizes a halftone processing unit to create two pixel groups with distinct dispersibility characteristics, ensuring their distributions are uncorrelated, and determines dot formation based on these characteristics to maintain image quality even with positional shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single dither mask with blue noise and green noise characteristics is used to determine dot arrangement, then image quality is improved by eliminating dot distribution unevenness, but computation time increases due to Fourier transform and threshold arrangement verification
Solution Approach 1:
The patent divides the pixel groups into two separate groups (first pixel group and second pixel group) with different dispersibility characteristics. Instead of using a single complex dither mask, two simpler dither masks are generated independently for each group, reducing the overall computation time while maintaining image quality through the combined effect of both groups.
Solution Approach 2:
The patent applies different dispersibility characteristics (first characteristic and second characteristic) to different pixel groups based on their local requirements. The first pixel group uses one dispersibility characteristic while the second pixel group uses another, allowing optimized dot arrangement for each region rather than applying a uniform approach across the entire image.
2Productivity
If dot forming position shifts occur between groups during bidirectional printing or overlapping print head operation, then printing speed is maintained, but image quality deteriorates due to visible unevenness in dot distribution
Solution Approach 1:
The patent changes the dispersibility parameters (first characteristic and second characteristic) for different pixel groups to make them less sensitive to positional shifts. By using uncorrelated dispersibility characteristics, the system maintains acceptable image quality even when dot forming positions shift during bidirectional printing or overlapping operations.
Solution Approach 2:
The patent performs preliminary arrangement of dots in each pixel group using predetermined dispersibility characteristics before the actual printing process. This pre-arrangement ensures that even if positional shifts occur during printing, the dot distribution remains optimized and uniform, preventing visible unevenness in the final image.
3Manufacturing precision
If multiple dither masks with different dispersibility characteristics are generated and applied to different pixel groups, then dot distribution uniformity is improved, but device complexity increases due to multiple processing units and characteristics
Solution Approach 1:
The patent segments the image processing into two independent pathways: one for the first pixel group using first dispersibility characteristics, and another for the second pixel group using second dispersibility characteristics. This segmentation allows each pathway to be processed independently with simpler logic, reducing overall processing complexity while achieving better dot distribution uniformity through the combination of both groups.
Data Source
AI summary
An output image includes a first pixel group, and a second pixel group. A halftone processing unit that performs halftone processing on a original image causes an arrangement of pixels where dots are formed in the first pixel group to have a distribution having a first characteristic relating to dispersibility, and in the second pixel group to have a distribution having a second characteristic relating to dispersibility and causes the distribution according to the second characteristic not to be correlated with the distribution according to the first characteristic when the input tone value of the original image is equal to or higher than a intermediate value. Then, the on and off of the dot in the arrangement having the first characteristic in the first pixel group is determined, and the on and off of the dot in the arrangement having the second characteristic in the second pixel group is determined.