Sensitivity Metamerism Index for Digital Still Camera

摘要

For a practical measurement of sensitivity metamerism index for digital still camera, we have proposed Camera Rendering Index (CRI) using color patches defined in CIE 13.3. We evaluated it from several aspects in this paper. First, based on 13 types of sensitivity sets including real camera sensitivity, correlations between sensitivity metamerism indexes and color error for the virtual representation of typical objects are investigated. CRI gives the best correlation among some sensitivity metamerism indexes in terms of linearity with potential color errors caused by metamerism. Second, we discuss CRI with some modified parameters and procedures such as choice of color patches, spectral deviations of color patches, evaluation of Special CRI, color difference formula, optimization of color matrix, and final index formula. We found that the choice of the CIE 13.3 color patches is reasonable, and their spectral characteristics are critical while the other parameters and procedures may be insignificant. Base on these evaluations, we are proposing this evaluation index for an ISO standard.