RESUMO
[ Objective]Quantitative characteristics of tongue color is investigated by colorimetrical method to supply evidence for the objectivity of tongue inspection. [Methods] Two hundred and seven tongue pictures with different tongue color were scanned. The values of R (red) , G (green) and B (blue) of different sampling spots in the pictures, as well as their ratios with the total value of R + G + B were observed. Purple-bluish tongue was clustered with the above indexes and then was compared with other common-colored tongue color. [Results] In light white tongue, G ratio was high, R ratio and B ratio low; in red tongue, R ratio was high, G ratio and B ratio low; in purple-bluish tongue, B ratio was higher, G ratio high and R ratio low. The total value of R + G + B was higher in light white tongue, high in purple-bluish tongue and low in red tongue. [Conclusion] There are colorimetrical characteristics in tongue pictures from different monographs of traditional Chinese medicine, but the colorimetric parameters of the tongue pictures should be applied according to clinical cases.