CCAD: A Basic Sample Database for Modeling Common Color Appearance

The consistency assessment of a set of cross-media color reproductions is an urgent research topic in color application field. This is enhanced by the various gamut devices which make it impossible to match exactly using conventional colourimetry metrics, which existed metrics for color consistency were developed for small gamut differences. When a set of color reproductions provided by fewer gamut interaction between sample and reference media are judged to show a high degree of similarity, they are usually regard as sharing a ‘Common Color Appearance’. This degree of similarity is just scaled by subjective assessment efficiently. In order to achieve and measure common color appearance, some offered metrics based on their private small and special color samples, which had restricted the applicability and evaluation of common color appearance metrics. On the basis of the adjustment & feedback frame, the proposed common color appearance databases (CCAD) including single-patch mode and image-patch model were implemented to provide a new solution for this issue. In this project, CRPCs data from ISO/PAS 15339 standard were selected as the standard data source. Firstly, ten specific color centers were selected from CRPC4 as primary references, meanwhile the corresponding color centers with same CMYK values in CRPCs (s set 1, 2, 3, 5, 6, 7) selected as the secondary references. Secondly, in each CRPCs gamut, twenty samples were generated by small adjustments of attributes including different combination between lightness, colorfulness and hue angle. Thirdly, similarity scaling values were achieved from category judgment method under the standard viewing condition, and color patch samples with highest similar degree were summarized by Mean-Opinion-Scores and Z-scores together. According to evaluation results, various similarity degree of color patch set and common color appearance set were both achieved with 95% confident interval. At last, using closeness trend line method, the adaptability and scalability of the proposed CCAD were verified to provide a basic data references for common color appearance metrics.