Some Problems And Solutions Of The CIECAM02

Since the recommendation of the CIECAM02 colour-appearance model by CIE TC 8-01 Colour appearance modeling for colour management systems!, it has been used to predict colour appearance under a wide range of viewing conditions, to specify colour appearance in terms of perceptual attributes, to quantify colour differences,to propose a uniform colour spaceand to provide a profile connection space for colour managements.However, through lots of experiments, Brill and S#sstrunk found that the so-called yellow-blue and purple problems existing in CIECAM02.In this paper, authors make concrete analyses of the reasons that cause the so-called yellow-blue and purple problems and reach a conclusion: if a nesting rule can be provided, then the yellow-blue and purple problems can be solved simultaneously, i.e., for all corresponding colors to lie inside the spectrum locus not go wrong after conversion, they must be nested: The HPE triangle must encompass the(modified) CAT02 triangle, whereas must encompass the spectrum locus in turn!.In this paper, the optimum solution to the problems has been adopted as a constrained non-linear optimization problem. An optimum solution resulting in a new CAT02 matrix is numerically obtained. This new matrix can not only satisfy the nesting rule, but also performs better than the Hunt-Pointer-Estevez(HPE) matrix in predicting both corresponding colour and colour appearance data sets. In addition, analyses of the original CAT02 matrix M02, the new matrix MOPT and the HPE matrix MOPT have been done through experimental data. Specifically, it was found that the new and HPE matrices perform significantly different on nine(out of 21) corresponding colour data sets and on all corresponding colour data sets as a whole. According to the results, the new matrix MOPT performed slightly worse than the original CAT02 matrix M02(1.0 CIELAB units worse, on the average).At last, a conclusion can be reached: In any case, the simultaneous solution of the yellow-blue and purple problems, together with the good prediction of available corresponding colour and colour appearance data sets, induce researchers to propose the MOPT matrix for future CIECAM02 revisions.