ISO/TS 20498-3:2020

TECHNICAL ISO/TS
SPECIFICATION 20498-3
First edition
2020-04
Traditional Chinese medicine —
Computerized tongue image analysis
system —
Part 3:
Colour chart
Médecine traditionnelle chinoise — Système d’analyse d’images
numérisées de la langue —
Partie 3: Nuancier
Reference number
©
ISO 2020
© ISO 2020
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ii © ISO 2020 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Classification . 2
4.1 Colour chart without registration mark . 2
4.2 Colour chart with registration mark . 2
5 Technical requirements . 3
5.1 Accuracy of L*a*b* value . 3
5.2 Colour patch size and margin . 4
5.3 Optical transparency . 5
5.4 Usage of colour chart . 5
5.5 Printing condition . 5
Annex A (informative) Characteristics of each colour patch and the usage of the colour chart .6
Annex B (informative) sRGB values of colour chart . 7
Annex C (informative) Printing condition of each colour patch. 8
Bibliography . 9
Foreword
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This document was prepared by Technical Committee ISO/TC 249, Traditional Chinese medicine.
A list of all the parts in the ISO 20498 series can be found on the ISO website.
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iv © ISO 2020 – All rights reserved

TECHNICAL SPECIFICATION ISO/TS 20498-3:2020(E)
Traditional Chinese medicine — Computerized tongue
image analysis system —
Part 3:
Colour chart
1 Scope
This document specifies the colour character and appearance of the colour chart used in a computerized
tongue image analysis system (CTIS).
This document excludes diagnostic or clinical comparison to the colour chart.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
colour chart
apparatus which consists of an array of 24 single-colour patches used for the evaluation of colour
reproduction of CTIS
3.2
colour space
geometric representation of colours in space, usually of three dimensions
[SOURCE: CIE Publication 17.4, 845-03-25]
3.3
CIELAB colour difference
CIE 1976 L*a*b* colour difference
*
DE
ab
difference between two colour stimuli defined as the Euclidean distance between the points
representing them in L*a*b* colour space
[SOURCE: CIE publication 17.4, 845-03-55, 56]
3.4
margin
area beyond the colour patch in the colour chart
4 Classification
4.1 Colour chart without registration mark
The order of colours in the colour chart and the example printed on paper using arbitral ink, dye and
paint are shown in Figure 1.
NOTE The numbers listed in the figure represent the order of colours in this colour chart.
Figure 1 — The colour chart without registration mark
4.2 Colour chart with registration mark
The order of colours in the colour chart and the example printed on paper using arbitral ink, dye and
paint with registration mark are shown in Figure 2.
2 © ISO 2020 – All rights reserved

NOTE The numbers listed in the figure represent the order of colours in this colour chart.
Figure 2 — The colour chart with registration
...