Ati Technologies Ulc

Yuxin Chen

David I J Glen

Keith Lee

Jie Zhou

David I Glen

Chun-Chin David Yeh

Yee Shun Chan

Systems, apparatuses, and methods for reducing three dimensional (3D) lookup table (LUT) interpolation error while minimizing on-chip storage are disclosed. A processor generates a plurality of mappings from a first gamut to a second gamut at locations interspersed throughout a 3D representation of the pixel component space. For example, in one implementation, the processor calculates mappings for 17×17×17 vertices within the 3D representation. Other implementations can include other numbers of vertices. Rather than increasing the number of vertices to reduce interpolation error, the processor calculates mappings for centroids of the sub-cubes defined by the vertices within the 3D representation of the first gamut. This results in a smaller increase to the LUT size as compared to increasing the number of vertices. The centroid mappings are used for performing tetrahedral interpolation to map source pixels in the first gamut into the second gamut with a reduced amount of interpolation error.

Reducing 3D lookup table interpolation error while minimizing on-chip storage

Systems, apparatuses, and methods for reducing three dimensional (3D) lookup table (LUT) interpolation error while minimizing on-chip storage are disclosed. A processor generates a plurality of mappings from a first gamut to a second gamut at locations interspersed throughout a 3D representation of the pixel component space. For example, in one implementation, the processor calculates mappings for 17&#xd7;17&#xd7;17 vertices within the 3D representation. Other implementations can include other numbers of vertices. Rather than increasing the number of vertices to reduce interpolation error, the processor calculates mappings for centroids of the sub-cubes defined by the vertices within the 3D representation of the first gamut. This results in a smaller increase to the LUT size as compared to increasing the number of vertices. The centroid mappings are used for performing tetrahedral interpolation to map source pixels in the first gamut into the second gamut with a reduced amount of interpolation error.

A data segmenter is configured to determine indices using numbers of most significant bits (MSBs) of fractional values of floating-point representations of component values of an input color that are selected based on exponent values of the floating-point representations. The component values are defined according to a source gamut. The data segmenter is also configured to determine offsets associated with the indices using subsets of the fractional values. An interpolator configured to map the input color to an output color defined according to a destination gamut based on a location in a three-dimensional (3-D) look up table (LUT) indicated by the indices and offsets.

Three dimensional (3-D) look up table (LUT) used for gamut mapping in floating point format

A processor is configured to store color component values associated with a first subset of vertices of a three-dimensional (3-D) look up table (LUT) in a first subset of memory elements. The color component values are defined according to a destination gamut. A data select module is configured to access the color component values from the first subset of the memory elements concurrently with the processor storing color component values associated with a second subset of the vertices of the 3-D LUT in a second subset of the memory elements. The data select module is configured to access the color component values from the first and second subsets of the memory elements in response to the processor storing the color component values associated with the second subset of the vertices of the 3-D LUT in the second subset of the memory elements. This process can be extended to additional subsets.

Multiple stage memory loading for a three-dimensional look up table used for gamut mapping

A three-dimensional (3-D) look up table (LUT) can be accessed using an address decoder to identify a plurality of vertices in the 3-D LUT based on a number (m) of most significant bits (MSBs) of three coordinate values representative of a first color and a non-zero integer (p). The three coordinate values are determined by a source gamut. One or more memories store component values representative of a plurality of second colors determined by a destination gamut. The component values are stored at memory locations associated with the plurality of vertices. An interpolator maps the input color to an output color in the destination gamut based on the component values.

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Markham, Canada

Yuxin Chen