Image Processing Coefficients Tone Correction Density Extrapolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image forming apparatuses face accuracy issues in tone correction, particularly in high density regions, where image processing coefficients may lose precision due to extrapolation when the maximum density of formed patch images is lower than the target maximum density.
Innovation Solution
The apparatus forms patch images using modified image processing coefficients that convert an input density of 100% into an output density of 100%, allowing for accurate interpolation and tone correction, thereby ensuring the target maximum density is achieved with reduced density errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If patch images are formed using image processing coefficients before updating, then the existing tone correction process can be maintained, but image processing coefficients in high density regions may lose accuracy due to extrapolation
Solution Approach 1:
The patent applies preliminary action by modifying image processing coefficients before forming patch images. Specifically, when the maximum density is less than 100%, the coefficients are pre-adjusted to ensure the maximum density becomes 100%, thereby preventing extrapolation errors in high density regions before they occur.
Solution Approach 2:
The patent changes the parameter of image processing coefficients by adjusting the output density conversion. When the original maximum density is below 100%, the coefficients are modified to map the maximum density to exactly 100%, transforming the density parameter relationship to eliminate extrapolation needs in high density regions.
2Ease of manufacture
If image processing coefficients convert input density of 100% into output density less than 100%, then the existing conversion relationship is maintained, but the target maximum density cannot be achieved and extrapolation is required
Solution Approach 1:
The patent changes the output density parameter in the image processing coefficients. Instead of maintaining the original conversion where 100% input density yields less than 100% output density, the coefficients are modified so that 100% input density converts to exactly 100% output density, ensuring target maximum density is achieved without extrapolation.
3Adaptability or versatility
If extrapolation is used to determine image processing coefficients in high density regions, then coefficients can be determined beyond measured range, but accuracy is lost in the extrapolated region
Solution Approach 1:
The patent applies preliminary action by pre-modifying the image processing coefficients to ensure the maximum density reaches 100% before patch image formation. This prevents the need for extrapolation in high density regions, maintaining measurement precision across the entire density range while still achieving full adaptability.
Data Source
Figure 1
Figure 2~3
Figure 4A~5
AI summary
An image forming apparatus includes: holding means for holding image processing coefficients, each of which representing a relationship between an input density and an output density of an image signal output to image forming means; and an updating means forupdating an image processing coefficient based on the relationship between densities of measurement images and densities of image signals for forming the measurement images. The updating means, when a maximum value of an output density of the image processing coefficients is smaller than a maximum value of the density of the image signal, forms at least one first measurement image in accordance with an image signal indicating a density higher than the maximum value of the output density of the image processing coefficients.