An ellipsoid chroma region of a chroma plane may be defined to specify a range of chromas for which a secondary chroma modification is to be applied, and to determine an output chroma for each chroma of the chroma plane based on the ellipsoid chroma region. Further, two or more different-shaped chroma...http://www.google.com/patents/US6763134?utm_source=gb-gplus-sharePatent US6763134 - Secondary color modification of a digital image
