ISO/CIE 11664-6:2014 測色 — Part 6: CIEDE2000色差式 | ページ 2

Foreword

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ISO/CIE 11664-6 was prepared by CIE Technical Committee TC 1-57 of Division 1 Vision and colour. as CIE S 014-6.

ISO/CIE 11664 consists of the following parts, under the general title Colorimetry:

• Part 1: CIE standard colorimetric observers
• Part 2: CIE standard illuminants
• Part 3: CIE tristimulus values
• Part 4: CIE 1976 L*a*b* Colour space
• Part 5: CIE 1976 L*u*v* Colour space and u', v' uniform chromaticity scale diagram
• Part 6: CIEDE2000 Colour-difference formula

Introduction

The three-dimensional colour space produced by plotting CIE tristimulus values ( X, Y, Z) in rectangular coordinates is not visually uniform, nor is the (x, y, Y) space nor the two-dimensional CIE (x, y) chromaticity diagram. Equal distances in these spaces and diagrams do not represent equally perceptible differences between colour stimuli. For this reason the CIE has standardized two more-nearly uniform colour spaces (known as CIELAB and CIELUV) whose coordinates are non-linear functions of X, Y and Z. Numerical values representing approximately the relative magnitude of colour differences can be described by simple Euclidean distances in these spaces or by more sophisticated colour-difference formulae that improve the correlation with the relative perceived size of differences. The purpose of this CIE International Standard is to define one such formula, the CIEDE2000 formula. The Standard is based on CIE Technical Report 142-2001.

The formula is an extension of the CIE 1976 L*a*b* colour-difference formula (ISO 11664-4:2008(E)/CIE S 014-4/E:2007) with corrections for variation in colour-difference perception dependent on lightness, chroma, hue and chroma-hue interaction. Reference conditions define material and viewing environment characteristics to which the formula applies.

1 Scope

This CIE International Standard specifies the method of calculating colour differences according to the CIEDE2000 formula.

The Standard is applicable to input values of CIELAB L*, a*, b* coordinates calculated according to ISO 11664-4:2008(E)/CIE S 014-4/E:2007. The Standard may be used for the specification of the colour difference between two colour stimuli perceived as belonging to reflecting or transmitting objects. This includes displays, if they are being used to simulate reflecting or transmitting objects and if the tristimulus values representing the stimuli are appropriately normalized. The Standard does not apply to colour stimuli perceived as belonging to areas that appear to be emitting light as primary light sources, or that appear to be specularly reflecting such light.

2 Normative References

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

3 Definitions, Symbols and Abbreviations

For the purposes of this International Standard, the terms and definitions given in CIE S 017/E:2011 (International Lighting Vocabulary), and the following symbols and abbreviations apply.

Bibliography