What is ISO 20498-4 about? 
ISO 20498-4 is the fourth part of the ISO 20498 series which discusses the use of traditional Chinese medicine. ISO 20498-4 specifies the performance criteria of peripheral visual instruments in the computerized tongue image analysis system (CTIS), including colour reproduction, distortion and resolution.
Who is ISO 20498-4 for?
ISO 20498-4 on CTIS is useful to:
- Manufacturers of Chinese medicine
- Companies dealing with image analyzing systems
- Retailers and suppliers of medicine
Why should you use ISO 20498-4 for?
Tongue diagnosis in Chinese medicine is a method through which diseases and disease patterns can be diagnosed by visual inspection of the tongue and its various features.
ISO 20498-4 specifies the performance of other visual instruments for CTIS such as:
- Colour reproduction, which has the ability to accurately reproduce the colour of the object
- Display resolution, which contains a number of distinct pixels displayed in each dimension
- Distortion, which deforms the shape of the image
As a user of ISO 20498-4, adopting the best industry guidance on performance criteria of instruments can enhance the quality and consistency of tongue images and reduce variations between diagnoses through computerized tongue image analysis.
