Glossy Color Tone Quantification via Specular Reflection Correction

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Solution Overview

Problem

Existing methods for converting the appearance of metallic gloss into numerical values fail to accurately represent the perceived glossiness, as the correlation between obtained values and the color tone of glossy colors felt by humans is low.

Innovation Solution

A color tone quantification apparatus and method that calculates a coefficient for correcting chromaticity measurements to account for specular reflection, using a goniophotometer to measure radiant intensities at various angles and a colorimeter to measure chromaticity, thereby outputting effective chromaticity as a stimulus value in a color space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If chromaticity is measured including specular reflection component, then measurement is simplified, but correlation with perceived color tone decreases

Engineering Contradiction:
Improvemeasurement simplicityVSAvoidcorrelation with perceived color tone
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent segments the reflected light into two distinct components: specular reflection light and diffuse reflection light. By separating these components spatially and measuring them independently, the system can selectively combine them to achieve accurate color tone representation while maintaining measurement feasibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the measurement parameters by introducing angular dependence. Instead of measuring chromaticity at a single angle, the system measures at multiple angles (including both specular and diffuse reflection directions) and uses angular information to calculate effective chromaticity, thereby improving correlation with perceived color tone.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If multiple measurement angles are used to account for spatial distribution, then color tone accuracy improves, but device complexity increases

Engineering Contradiction:
Improvecolor tone accuracyVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the light receiver multi-functional by enabling it to measure both radiant intensity (for glossiness) and chromaticity (for color tone) at various angles. This universal measurement capability allows the system to obtain multiple types of data using a single receiver position, reducing the need for separate specialized sensors.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent adds the angular dimension to the measurement process. By measuring light properties at multiple angles around the sample, the system captures the spatial distribution of reflected light without requiring complex multi-position mechanical systems, thus achieving accurate color tone measurement with moderate device complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

The method increases the correlation with the perceived color tone of glossy colors, enabling more accurate representation and communication of glossy colors in industries like printing and advertising.

Implementation Method 1

measurement of reflected light that is measurement light which a region of an object is irradiated with and which is reflected off the region

Methodology Applied
Scientific EffectSpecular reflection: Reflection

Implementation Method 2

R, C, and B values of light of diffuse reflection from the object

Methodology Applied
Scientific EffectDiffuse reflection: Scattering

Implementation Method 3

a colorimeter that measures chromaticity of the region onto which the measurement light is incident in the object

Methodology Applied
Scientific EffectChromaticity measurement: Photoelectric Effect

Data Source

PatentEP3767257B1Color tone quantification device for glossy color, color tone measurement device for glossy color and color tone quantification method for glossy color
Publication Date: 2023.09.20 KONICA MINOLTA INC
  • EP3767257B1 patent drawingFigure 1
  • EP3767257B1 patent drawingFigure 2
  • EP3767257B1 patent drawingFigure 3

AI summary

A color tone quantification device for a glossy color, in which the correlation with the color tone of the glossy color visually perceived by humans is further enhanced, is provided. The device comprises a coefficient calculation unit that calculates a coefficient calculated in consideration of a spatial distribution which is to be used to correct the chromaticity measured by a method including a specular reflection component obtained by measuring the reflection light obtained by reflection of measurement light to an area of an object; a chromaticity calculation unit that calculates an effective chromaticity obtained by weighting the chromaticity measured by the method including the specular reflection component with the coefficient calculated by the coefficient calculation unit; and an output unit that outputs the effective chromaticity as a stimulus value representing a glossy color of the area in a color space.