| 摘要 |
A method of rendering a colour image on a designated output medium (49) is disclosed which maps colors to the gamut (44) of the designated output medium (49) performing gamut mapping (FIG. 9) earlier in the image synthesis process than current gamut method methods, at the point where information about object primitives and their spectral attributes in a scene description is available, but after the fixed scene geometry has been determined by the rendering system. The method makes use of the output of a symbolic rendering system which produces symbolic pixel expressions (80), having basis spectra variables which represent the interplay of light and object primitives in the scene description, and spectral data (84) having colour information about the light and object primitives in the scene, and which is indexed to the basis spectra variables. The method performs spectral change calculations (90) using the symbolic pixel expressions (80), the spectral data (84), and spectral information about the gamut (44) of the specific output medium (49) to determine the modifications (86) to the original spectral data that need to be made to the individual object primitives in the scene in order to produce image pixel colours which are in the gamut (44) of the output medium (49). The resulting image colours are locally and globally consistent with the semantics of the image, make effective use of as much of the available gamut of the display device as is possible, and require no further post-rendering gamut mapping prior to display or reproduction on the designated medium. <IMAGE> |
