Chapter 5: Color Analysis 5.1 CIE L*a*b* system : most popular system PGS.TS Trương Vĩnh Chapter 5: Color Analysis 5.2 Manipulation of data CIE từ viết tắc Commission Internationale de l’ Éclairage Ủy ban đo lường chiếu sáng quốc tế (1986) L = lightness or darkness +a = redness -a = greenness +b = yellowness -b = blueness Chroma = (a2 + b2)1/2 PGS.TS Trương Vĩnh Chapter 5: Color Analysis 5.2 Manipulation of data Theta (ϴ ): is the angle that a line joining the point in Hunter space with the origin makes with the horizontal axis ϴ = tan (a/b) ϴ = : red ϴ = 90o : yellow ϴ = 180o : green Using ϴ and L for analysis of the variance Δ = indicate how much sample and standard differ from one another PGS.TS Trương Vĩnh Chapter 5: Color Analysis Yellownecs (+b) 5.2 Manipulation of data Theta (ϴ ): is the angle that a line joining the point in Hunter space with the origin makes with the horizontal axis ϴ = tan (a/b) ϴ Redness (+a) PGS.TS Trương Vĩnh