Study on Turquoise ’ s Green Color Grading and Quality Evaluation of Color Based on CIE1976 L * a * b * Uniform Color Space

Abstract

Based on CIE1976 L * a * b * uniform color space, we quantitatively measure d 52 pieces of green turquoise about L * , a * and b * under illuminant D65. These colors were divided well into seven categories by Kmeans clustering analysis and the conseque n ce from ANOVA illustrated that there was evident difference among every category ’ s L * , a * and b * . By Fisher discriminant analysis to summarize the difference among various categories, every category ’ s L * , a * and b * were substituted into seven linear discriminant functions to verif y the accuracy of clustering. The accuracy was 98.1% and met requirement to turquoise green color grading . Combing with naked eyes ’ observation, turquoise ’ s green color was graded into seven levels for light and chroma, consisting of Fancy Vivid(FV), Fancy Intense(FI), Fancy Deep(FDe), Fancy(F), Fancy Dark(FDa), Fancy Light(FL), Light(L).