Linear Uniform Colour Space Composed of Simple Transformations of Tristimulus Values X, Y and Z

A new linear uniform colour space has been developed by systematic combinations of tristimulus values X, Y and Z. For colours with constant value of 6 in Munsell space, numerical computer analyses have been made to minimize the deformations of hue circles from uniform circles in the new space by optimizing the coefficients in the formulae of linear transformations. By appropriate transformations, the shapes of hue circles which are distorted in the L*a*b*, L*u*v* and Cube-Root spaces come close to uniform circles, and the warps of hue circles with moderate chroma are reduced to 1/4∼1/5 as compared with those in the traditional colour spaces. In this new space, hue and chroma can be approximated by metric hue angle and metric chroma, respectively, with considerable accuracy for colours of moderate chroma.