GB/T 7921-2008 English PDF

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GB/T 7921-2008: Uniform color space and color difference formula
Status: Valid

GB/T 7921: Historical versions

Standard ID	USD	BUY PDF	Lead-Days	Standard Title (Description)	Status
GB/T 7921-2008	279	Add to Cart	3 days	Uniform color space and color difference formula	Valid
GB/T 7921-1997	599	Add to Cart	4 days	Uniform colour space and colour difference formula	Obsolete
GB/T 7921-1987	RFQ	ASK	3 days	Uniform colour space and colour difference formula	Obsolete

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Basic data

Standard ID: GB/T 7921-2008 (GB/T7921-2008)
Description (Translated English): Uniform color space and color difference formula
Sector / Industry: National Standard (Recommended)
Classification of Chinese Standard: A20
Classification of International Standard: 17.180.20
Word Count Estimation: 12,175
Date of Issue: 2008-06-26
Date of Implementation: 2009-03-01
Older Standard (superseded by this standard): GB/T 7921-1997
Adopted Standard: CIE 15-2004, NEQ; CIE 142-2001, NEQ
Regulation (derived from): Announcement of Newly Approved National Standards No. 10 of 2008 (total 123)
Issuing agency(ies): General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China, Standardization Administration of the People's Republic of China
Summary: This standard provides a visual approximation of uniform CIE 1976 (Lab) color space and the CIE 1976 (Luv) color space and the corresponding color difference formulas and CIE DE2000 color difference formula is calculated. This standard applies to the object representation of color and light color and color representation and calculations.

GB/T 7921-2008: Uniform color space and color difference formula

---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
Uniform color space and color difference formula ICS 17.180.20 A20 National Standards of People's Republic of China Replacing GB/T 7921-1997 Uniform color space and color difference equation Posted 2008-06-26 2009-03-01 implementation Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China Standardization Administration of China released

Foreword

This corresponds to the standard CIE publication CIE15.2004 "colorimetric" and CIE142.2001 "industrial color evaluation Improvement ", and CIE15.2004 and CIE142.2001 non-equivalent degree of coincidence, the main differences are as follows. --- Part of the formula to calculate ΔH Raochou and ΔH u vp is not employed; --- Adjustment calculation CIEDE2000 color difference formula calculation steps. This standard replaces GB/T 7921-1997 "uniform color space and color difference equation." The main changes compared to 7921-1997 standard and GB/T as follows. --- Standardization of terminology and text according to CIE15.2004 update. To the GB/T 7921-1997 "CIE1976 u 'vp' average Uniform chromaticity diagram (CIE1976 u 'vp' Figure) "," CIE1976L u vp   color space, "" lightness index "were changed to" CIE1976 uniform Chromaticity scale diagram (UCS diagram) "," CIE1976 (L u   vp) color space "and" CIE1976 lightness "and" CIELAB color space Saturation "," CIELUV saturation color space, "" hue angle "and" Saturation "and other terms were updated; --- Modify CIELAB color space constraint expressions will modify 0.008856 (24/116) 3, see this standard formula (2) to (8); --- Increasing the calculation method ΔH Raochou and ΔH u vp alternative; --- Increased CIEDE2000 color difference formula for calculation method and experimental visual evaluation standard conditions described (Chapter 6 of this standard); --- Delete Chapter 7 (color representation and color units) and Chapter 8 (calculated color difference), the corresponding content are combined And to 5.1 and 5.2; --- The standard Tables 1 and 2 with the GB/T 7921-1997 Table 3 in 1 increase compared to the CIE illuminant D50, D55 and D75 Chromaticity values \u200b\u200band chromaticity coordinates of each lighting body x0, y; --- Removed CIE1976 uniform chromaticity scale diagram of illumination chromaticity coordinate point C; --- Delete Table 1, Table 2, Table 4; Appendix A of this standard is an informative annex. The standard color by the National Standardization Technical Committee and centralized. This standard was drafted. China Institute of Metrology, Shenzhen Haichuan Industry Corp.. The main drafters of this standard. Ma Yu, Lin Yi Ge, Chen Ping, HE Wei-ping, Tang Hui Gong. This standard replaces the standards previously issued as follows. --- GB/T 7921-1987, GB/T 7921-1997. Uniform color space and color difference equation

1 Scope

This standard specifies the visually approximately uniform CIE1976 (L Rao   Chou) color space and CIE1976 (L u   vp) color space And the appropriate color formulas and calculation methods CIEDE2000 color formula. Representation and calculation object This standard applies to color and light color representation and chromatic aberration.

2 Normative references

The following documents contain provisions which, through reference in this standard and become the standard terms. For dated references, subsequent Amendments (not including errata content) or revisions do not apply to this standard, however, encourage the parties to the agreement according to study Whether the latest versions of these documents. For undated reference documents, the latest versions apply to this standard. GB/T 5698 color terms 101 CIE publication. Impact Assessment of 1993 color parameters 142 CIE publication.2001 industrial color difference evaluation Improvement

3 Terms and Definitions

GB/T 5698 and identified the following terms and definitions apply to this standard. 3.1 In CIE1976 uniform color space, color indicates the brightness of the object coordinate notation as. L. 4 CIE1976 uniform chromaticity scale diagram (UCS diagram) CIE1976 uniform chromaticity scale diagram by the CIE1931 chromaticity diagram for the projection transformation obtained in the visual than the x, y color space chromaticity diagram Between more uniform, see Figure 1. ......

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