ISO 20498-2:2017
(Main)Traditional Chinese medicine - Computerized tongue image analysis system - Part 2: Light environment
Traditional Chinese medicine - Computerized tongue image analysis system - Part 2: Light environment
ISO 20498-2:2017 specifies the light environment necessary for the functioning of a computerized tongue image analysis system (CTIS). ISO 20498-2:2017 does not include the electrical safety and biocompatibility of the lighting component.
Médecine traditionnelle chinoise — Système d’analyse d’images numérisées de la langue — Partie 2: Environnement lumineux
General Information
- Status
- Published
- Publication Date
- 16-May-2017
- Technical Committee
- ISO/TC 249 - Traditional Chinese medicine
- Current Stage
- 9093 - International Standard confirmed
- Start Date
- 18-Nov-2022
- Completion Date
- 13-Dec-2025
Overview
ISO 20498-2:2017 specifies the light environment required for a Computerized Tongue Image Analysis System (CTIS). The standard defines optical conditions on the effective surface area where a patient’s tongue is imaged - covering illuminance, colour temperature, colour rendering, illumination uniformity, irradiance and ultraviolet (UV) irradiance. It does not cover electrical safety or biocompatibility of lighting components.
Keywords: ISO 20498-2:2017, CTIS, computerized tongue image analysis system, light environment, illuminance, colour temperature, colour rendering index, irradiance, ultraviolet irradiance.
Key topics and technical requirements
- Illuminance: 500 lx to 13 000 lx across the effective surface area.
- Colour temperature (CCT): 3 000 K to 7 000 K to control visual appearance and sensor response.
- Colour rendering index (CRI): > 90 to ensure accurate colour reproduction for diagnostic analysis.
- Illumination distribution (uniformity): ratio of minimum to maximum illuminance on the effective area must be > 0.9 (high uniformity).
- Irradiance (300–2 500 nm): total irradiance shall not exceed 350 W·m–2 (thermal/retinal/skin risk control).
- Effective UV irradiance (200–400 nm): shall not exceed 0.008 W·m–2 using the spectral weighting function in Annex A (actinic hazard assessment).
- Test methods: specifies a measuring grid (partial surfaces with centres ≤3 cm apart) and measurement procedures: illuminance meter for lux, spectroradiometer/sensor for spectral irradiance and UV, CRI measurement per CIE 013.3-1995. Sensor for irradiance measurements should have diameter ≤ 3 cm; measure at the point of maximum illuminance.
Applications and practical value
- Ensures consistent, repeatable imaging conditions for automated tongue diagnosis in Traditional Chinese Medicine (TCM) and related clinical workflows.
- Guides selection and validation of lighting systems for CTIS devices - important for manufacturers, system integrators and test labs.
- Protects patient safety by limiting thermal and photobiological exposure (irradiance and UV limits).
- Improves diagnostic reliability by enforcing high CRI and strict uniformity, reducing colour and shading artifacts that can skew image analysis algorithms.
- Useful for clinical deployment, device certification, quality assurance, and imaging protocol development.
Who should use this standard
- CTIS and medical imaging device manufacturers
- Clinical engineers, quality managers and regulatory/compliance teams
- Test laboratories and certification bodies
- Researchers developing tongue image analysis algorithms and imaging protocols
- TCM clinics adopting digital diagnostic tools
Related standards
- CIE 013.3-1995 (colour rendering measurement methods)
- IEC 62471:2006 (photobiological safety - referenced for UV weighting)
- Other parts of the ISO 20498 series (see ISO website for the full list)
Frequently Asked Questions
ISO 20498-2:2017 is a standard published by the International Organization for Standardization (ISO). Its full title is "Traditional Chinese medicine - Computerized tongue image analysis system - Part 2: Light environment". This standard covers: ISO 20498-2:2017 specifies the light environment necessary for the functioning of a computerized tongue image analysis system (CTIS). ISO 20498-2:2017 does not include the electrical safety and biocompatibility of the lighting component.
ISO 20498-2:2017 specifies the light environment necessary for the functioning of a computerized tongue image analysis system (CTIS). ISO 20498-2:2017 does not include the electrical safety and biocompatibility of the lighting component.
ISO 20498-2:2017 is classified under the following ICS (International Classification for Standards) categories: 11.040.99 - Other medical equipment. The ICS classification helps identify the subject area and facilitates finding related standards.
ISO 20498-2:2017 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 20498-2
First edition
2017-05
Traditional Chinese medicine —
Computerized tongue image analysis
system —
Part 2:
Light environment
Médecine traditionnelle chinoise — Système d’analyse d’images
numérisées de la langue —
Partie 2: Environnement lumineux
Reference number
©
ISO 2017
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
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ii © ISO 2017 – All rights reserved
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Technical requirements . 1
4.1 Illuminance. 1
4.2 Colour temperature . 2
4.3 Colour rendering index . 2
4.4 Illumination distribution. 2
4.5 Irradiance . 2
4.6 Ultraviolet irradiance . 2
5 Test methods . 2
5.1 Measuring points on effective surface area . 2
5.2 Illuminance. 3
5.3 Colour temperature . 3
5.4 Colour rendering index . 3
5.5 Illumination distribution. 3
5.6 Irradiance . 3
5.7 Ultraviolet irradiance . 4
Annex A (informative) Spectral weighting function for assessing ultraviolet hazards .5
Bibliography . 6
Foreword
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