Abstract: In order to find out a simple operation and reasonable process to classify the natural green cocoons which have various shades of color,a DigiEye color tester was used for color measurement of the natural green cocoons of the same color system. The CIEDE2000 color-difference formula was abopted and classification results of human eye were combined. It was found that the minimum chromatic aberration needed for human eyes distinguishing two natural green cocoons with different shades is1.8. The color values of a batch of natural green cocoons are sequenced by b* and minimum b* are both dealt with integer function and the b* fixed increment is set as 6. Then the whole natural green cocoons could be divided into 10 categories. The minimum percentage of cocoon number in each category that human eye can distinguish is 0 and the maximum one is 14.5. The minimum chromatic aberration between every two categories is 1.6, and the color separation effect of every category is obvious.

Key words: natural green cocoon, color separation, color, color difference, CIEDE2000 color-difference formula