Color Shift Correction in Image Scanning via Distance Variation
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Solution Overview
Problem
Conventional image-reading apparatuses fail to accurately reproduce color images when the angle and distance between the reading sensor and the document change during scanning, leading to color shifts and poor image quality.
Innovation Solution
An image-reading apparatus with a variation acquiring unit that measures changes in distance or angle between the medium and the imaging unit or light source, and a color shift correcting unit that calculates and corrects color shifts based on these variations, using a correction table to ensure accurate color reproduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional image-reading apparatuses are used, then the device structure is simple, but color shift occurs when angle and distance change during scanning
Solution Approach 1:
The patent creates a correction table in advance that stores correspondence between distance/angle variations and color shift correction values. This preliminary preparation allows the system to quickly correct color shifts during scanning without complex real-time calculations, resolving the contradiction between reliability and device complexity.
Solution Approach 2:
The patent changes the approach from physical adjustment of optical parameters to digital parameter correction. By storing correction values for different distance and angle conditions in a lookup table, the system corrects color shifts through parameter transformation rather than physical modification, maintaining simplicity while improving color reproduction accuracy.
2Reliability
If color shift correction is performed in real-time, then color reproduction accuracy improves, but processing time increases
Solution Approach 1:
The correction table is pre-generated and stored, containing all necessary correction values for various distance and angle conditions. During actual scanning, the system only needs to lookup and apply the pre-computed correction values, eliminating time-consuming real-time calculations while maintaining high color reproduction accuracy.
Solution Approach 2:
The patent uses a correction table that copies pre-calculated correction data for different scanning conditions. Instead of performing complex correction calculations in real-time, the system retrieves copied correction values from the table, significantly reducing processing time while preserving color accuracy.
3Productivity
If the reading sensor moves at high speed, then scanning efficiency improves, but color shift variation increases
Solution Approach 1:
The system incorporates feedback mechanisms to detect actual distance and angle variations during high-speed scanning. By continuously monitoring these parameters and referring to the pre-stored correction table, the system dynamically adjusts color correction values to maintain color consistency despite rapid sensor movement, thus resolving the contradiction between productivity and reliability.
Data Source
AI summary
An image-reading apparatus, includes a variation acquiring unit that acquires a variation of a distance or an angle between a medium to be read and an imaging unit or a light source, and a color shift correcting unit that calculates a color shift between the medium and the imaging unit or the light source based on the variation acquired by the variation acquiring unit and corrects the color shift.