US 2008/0174608 A1Published application

Method for selecting a color transformation

AssigneeAgfa Graphics NV

InventorsMarc Mahy, Paul Delabastita

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Abstract

An output color profile, such as an ICC output profile, contains a look-up table to separate the color of a pixel, for example a CIELAB color, into a set of colorant values, for example CMYK colorants. In practice, most CMYK images have been separated using one of a limited set of standardized output profiles. The invention deals with the problem of guessing which one of these standardized output profiles has been used to separate a specific image. For this purpose the CMYK values of the image are analyzed. The analysis involves calculating a distance in the CMYK space between the CMYK values of an image, and the CMYK values produced by different output profiles. A profile is selected based on these distances, for example by selecting the profile yielding the shortest distance.

Claims16

Dependent claims

A method for determining if a destination profile belonging to a set of candidate destination profiles was used to transform a source image into a destination image, whereby each destination profile comprises entries defined in a source space, whereby for each entry a destination vector in a destination space is available, the method comprising:

obtaining at least one destination pixel of a destination image, said pixel having a destination vector in said destination space;
transforming said destination vector into an approximate destination vector in said destination space using said destination profile;
calculating a distance between said destination vector and said approximate destination vector of said at least one pixel;
and
determining based on said distance if said destination profile was used to transform a source image into said destination image.

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Dependencies are inferred from the claim text.