Method for identifying color of flue-cured tobacco

The invention provides a method for identifying the color of primary flue-cured tobacco. The method comprises the following steps: 1) taking the back surface of the primary flue-cured tobacco as an identification surface; 2) determining the length and the main vein of the flue-cured tobacco leaves; 3) uniformly selecting three position points on the main pulse from the stem end of the main pulse to the tip end of the main pulse; 4) taking the main pulse as a symmetry axis, selecting six points as measuring points at positions which are 2cm-4cm away from the two sides of the three position points, and measuring the reflection spectrum of the back surface of the primary flue-cured tobacco through a spectrophotometer; (5) respectively carrying out second derivative processing on the reflection spectrums of the measuring points to obtain a second derivative value at 500nm, a second derivative value at 670nm, a second derivative value at 520nm and a second derivative value at 640nm; (6) obtaining the color scale o