目的观察常用色彩空间哪个通道(或分量)善于反映舌质舌苔的区别并有助于舌质舌苔的分割。方法以典型舌图(淡红舌薄白苔、腻苔、黄苔等)和色温偏低的舌图为研究对象,在红、绿、蓝三色(RGB),国际照明委员会1976 L^*a^*b^*标准(CIELAB)和色调、饱和度、亮度(HSI)色彩空间下选择舌图上每个像素的特定色彩分量(a^*分量、L^*分量、H分量、R分量)作为聚类对象。使用K-均值聚类聚成2个集合,按照生成的2个集合的特征完成分割。结果显示CIELAB色彩空间a^*分量对舌质舌苔分割的效果和抗干扰能力最好,不受光照角度、色温偏差、舌苔舌质类型等因素的影响。L^*分量、R分量的聚类结果受光照不均匀的影响明显,H分量的聚类结果多呈分割不完全状态。结论基于K-均值聚类的以CIELAB色彩空间a^*分量为指标对舌质舌苔进行分割的效果较稳定,在舌诊中有一定的实用价值。
Objective To observe which pathways (or components) of common color spaces are good for discriminating and segmenting tongue body and fur. Methods The typical tongue image (pink tongue with thin-white fur, greasy fur and yellow fur) and lower color temperature tongue image were taken as study objects, and special color component of every pixel of tongue imagines (value of a * , L * , H and R) in the color spaces of red, green and blue ( RGB), L * a * b * criterion of International Commission on Illumination in 1976 (CIELAB), and hue, saturation and intensity (HSI) were selected as clustering objects. K-means clustering was applied to generate two clusters and complete the segmentation according to the characteristics of them. Results The component of a* value of CIELAB color space was the best in the segment effect and anti-interference capability, which was not influenced by illumination angle, bias of color temperature and types of tongue body and fur. The clustering results of L* value and R value were influenced by uneven illumination significantly. The clustering result of H value showed a state of incomplete segmentation. Conclusion The segmentation of tongue body and fur had a stable result taking a* value in CIELAB color space based K-means clustering as index and showed practical values in tongue diagnosis.