Changes in the TDCH variables according to the presence of sleep disorder from the first and second experiments were calculated in 18 subjects.
Differences in the TDCH variables between the normal and the sleep disorder groups were assessed in the first experiment.
The seven variables of the TDCH included the color ranges of both the tongue body and the tongue coating because the color ranges were derived from the color distribution of the entire tongue area.
Table 7 shows the classification results using the seven TDCH variables in the first experiment based on Naive Bayes, k-nearest neighbor, and support vector machine methods [35, 36].
Differences in the tongue color between the normal and the sleep disorder groups were derived from the seven TDCH variables in this study.