Constructing spectral gamut boundary descriptors

A color management module stored in a memory, wherein the color management module is executed by at least one processor to convert a source-side color in a source device dependent color space into a counterpart destination-side color in a destination device dependent color space, said color management module comprising:

• an image access module constructed to perform an accessing step in which a multi-spectral color image generated in the source device dependent color space by using a multi-spectral source device is accessed;
• a forward source device conversion module constructed to perform a converting step in which the multi-spectral color image is converted into a spectral reflectance representation in a spectral reflectance space;
• an ICS conversion unit constructed to perform a converting step in which the spectral reflectance representation is converted into a spectrally-based Interim Connection Space (ICS) representation in a spectrally-based ICS;
• a gamut mapping module constructed to perform a gamut mapping step in which each spectrally-based ICS value of the spectrally-based ICS representation is spectrally gamut mapped onto a spectral gamut of a destination device using a simplified spectral Gamut Boundary Descriptor (GBD) that represents the spectral gamut boundary of the destination device;
• an inverse destination device color conversion module constructed to perform a converting step in which each gamut-mapped spectrally-based ICS value is converted into a destination-side color in the destination device dependent color space of the destination device,
• wherein the simplified spectral GBD is constructed by generating sample points that span the spectral gamut of the destination device, forming a full spectral GBD by applying a hulling algorithm to the sample points, identifying sample points that are vertices of the full GBD of the spectral gamut, partitioning the vertices of the full GBD into clusters, such that the clusters are at least at a certain threshold distance apart, choosing a representative sample point from each cluster, and forming the simplified spectral GBD by applying the hulling algorithm to the representative sample points from each cluster.

A color management apparatus comprising:

• a computer-readable memory constructed to store computer-executable process steps;
• and
• a processor constructed to execute the computer-executable process steps stored in the memory;
• wherein the process steps stored in the memory cause the processor to convert a source-side color in a source device dependent color space into a counterpart destination-side color in a destination device dependent color space, and include computer-executable process steps to:
• access a multi-spectral color image in the source device dependent color space generated using a multi-spectral source device;
• convert the multi-spectral color image into a spectral reflectance representation in a spectral reflectance space;
• convert the spectral reflectance representation into a spectrally-based Interim Connection Space (ICS) representation in a spectrally-based ICS;
• spectrally gamut map each spectrally-based ICS value of the spectrally-based ICS representation onto a spectral gamut of a destination device using a simplified spectral Gamut Boundary Descriptor (GBD) that represents the spectral gamut boundary of the destination device;
• and
• convert each gamut-mapped spectrally-based ICS value into a destination-side color in the destination device dependent color space of the destination device,
• wherein the simplified spectral GBD is constructed by generating sample points that span the spectral gamut of the destination device, forming a full spectral GBD by applying a hulling algorithm to the sample points, identifying sample points that are vertices of the full GBD of the spectral gamut, partitioning the vertices of the full GBD into clusters, such that the clusters are at least at a certain threshold distance apart, choosing a representative sample point from each cluster, and forming the simplified spectral GBD by applying the hulling algorithm to the representative sample points from each cluster.

A non-transitory computer-readable memory medium on which is stored computer-executable process steps for causing a computer to convert a source-side color in a source device dependent color space into a counterpart destination-side color in a destination device dependent color space, said process steps comprising:

• accessing a multi-spectral color image in the source device dependent color space generated using a multi-spectral source device;
• converting the multi-spectral color image into a spectral reflectance representation in a spectral reflectance space;
• converting the spectral reflectance representation into a spectrally-based Interim Connection Space (ICS) representation in a spectrally-based ICS;
• spectrally gamut mapping each spectrally-based ICS value of the spectrally-based ICS representation onto a spectral gamut of a destination device using a simplified spectral Gamut Boundary Descriptor (GBD) that represents the spectral gamut boundary of the destination device;
• and
• converting each gamut-mapped spectrally-based ICS value into a destination-side color in the destination device dependent color space of the destination device,
• wherein the simplified spectral GBD is constructed by generating sample points that span the spectral gamut of the destination device, forming a full spectral GBD by applying a hulling algorithm to the sample points, identifying sample points that are vertices of the full GBD of the spectral gamut, partitioning the vertices of the full GBD into clusters, such that the clusters are at least at a certain threshold distance apart, choosing a representative sample point from each cluster, and forming the simplified spectral GBD by applying the hulling algorithm to the representative sample points from each cluster.