Image Processing Apparatus OBA Chromaticity Conversion
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Solution Overview
Problem
Color management systems face inaccuracies when using color measurement devices with fixed light sources, particularly when dealing with papers containing optical brightening agents (OBA), as they fail to account for ultraviolet light effects, leading to discrepancies between colorimetric values and actual appearances.
Innovation Solution
An image processing apparatus that includes a sensor with a fixed light source, a unit to determine the OBA amount in sheets, and a chromaticity value conversion unit, which adjusts measurements based on designated conditions to align with either ISO 12655-2009 'M0' or 'M1' standards, ensuring accurate color representation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a color measurement device with a fixed light source is used, then the device structure is simple and easy to operate, but the measurement precision deteriorates when dealing with papers containing optical brightening agents due to inability to account for ultraviolet light effects
Solution Approach 1:
The patent changes the parameter of light source characteristics by providing a plurality of light sources with different spectral distributions (including UV light sources) and selectively switching between them based on the measurement conditions and paper type, thereby achieving both ease of operation and measurement precision
Solution Approach 2:
The system dynamically adapts by automatically selecting appropriate light sources and converting chromaticity values based on the measured paper characteristics and designated measurement conditions (M0 or M1), transforming a static fixed light source system into a dynamic multi-condition measurement system
2Device complexity
If a fixed light source is used in the sensor, then the device complexity is reduced, but the measurement accuracy deteriorates because it cannot simulate different measurement conditions (M0 and M1) required for accurate color representation
Solution Approach 1:
The measurement device achieves multi-functionality by incorporating multiple light sources that can simulate different measurement conditions (M0 without UV, M1 with UV), allowing a single device to perform multiple measurement types that would otherwise require separate specialized devices
Solution Approach 2:
The patent introduces a chromaticity value conversion unit as an intermediary that processes the raw measurement data and converts it to the desired measurement condition, mediating between the physical light source limitations and the required measurement standards
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables accurate color management by automatically determining OBA content and converting chromaticity values to match the appropriate measurement condition, reducing measurement errors and ensuring compatibility with human visual perception.
Implementation Method 1
The OBA acts in accordance with a principle of fluorescence and thus absorbs ultraviolet (UV) radiation whose wavelength is 400 nanometers (nm) or less and emits light in a region mainly of the blue visible spectrum of 400 to 450 nm
Data Source
AI summary
An image processing apparatus includes an acquisition unit configured to acquire a chromaticity value, which is a measurement result for a sheet to be measured, by using a sensor in which a light source has fixed characteristics; a designation unit configured to designate a condition under which the measurement result is acquired by the sensor; a determination unit configured to determine an optical brightening agent amount contained in the sheet; and a chromaticity value conversion unit configured to convert the chromaticity value, which is acquired by the acquisition unit, by using the condition designated by the designation unit and information about the optical brightening agent amount determined by the determination unit.