Alpha blending palettized image data

Claim 3

The method of claim 1, wherein the mapping of pixels by step (c) to the index space and the mapping of the blended pixels by step (e) to the CLUT indices are based on a characterized structure of the CLUT.

Claim 4

The method of claim 1, wherein, for each pixel of the first set: step (c) comprises the step of mapping the corresponding CLUT index for the pixel to two indices in the index space; step (d) comprises the step of generating three coordinates of a blended pixel using the two indices in the index space as indices to one or more lookup tables; and step (e) comprises the step of using at least one of the coordinates of the blended pixel as an index to a lookup table to map the blended pixel to a CLUT index of the palettized blended image data.

Claim 5

The method of claim 1, wherein the palettized image data is represented by CLUT indices and for each pixel of the first set: step (c) comprises the steps of: (1) mapping the CLUT index for the pixel of the first set to a first UV index and a first Y index in the index space; and (2) mapping the CLUT index for the corresponding pixel of the second set to a second UV index and a second Y index in the index space; step (d) comprises the steps of: (1) generating a U coordinate of a blended pixel using the first UV index as an index to a U lookup table and the second UV index as an index to the U lookup table; (2) generating a V coordinate of the blended pixel using the first UV index as an index to a V lookup table and the second UV index as an index to the V lookup table; and (3) generating a Y coordinate of the blended pixel using the first Y index and the second Y index; and step (e) comprises the step of using the U and V coordinates of the blended pixel as indices to a UV lookup table to map the blended pixel to a CLUT index of the palettized blended image data.

Claim 8

The apparatus of claim 5, wherein the mapping of pixels by means (c) to the index space and the mapping of the blended pixels by means (e) to the CLUT indices are based on a characterized structure of the CLUT.

Claim 9

The apparatus of claim 5, wherein, for each pixel of the first set: means (c) maps the corresponding CLUT index for the pixel to two indices in the index space; means (d) generates three coordinates of a blended pixel using the two indices in the index space as indices to one or more lookup tables; and means (e) uses at least one of the coordinates of the blended pixel as an index to a lookup table to map the blended pixel to a CLUT index of the palettized blended image data.

Claim 10

The apparatus of claim 5, wherein the palettized image data is represented by CLUT indices and for each pixel of the first set: means (c): (1) maps the CLUT index for the pixel of the first set to a first UV index and a first Y index in the index space; and (2) maps the CLUT index for the corresponding pixel of the second set to a second UV index and a second Y index in the index space; means (d): (1) generates a U coordinate of a blended pixel using the first UV index as an index to a U lookup table and the second UV index as an index to the U lookup table; (2) generates a V coordinate of the blended pixel using the first UV index as an index to a V lookup table and the second UV index as an index to the V lookup table; and (3) generates a Y coordinate of the blended pixel using the first Y index and the second Y index; and means (e) uses the U and V coordinates of the blended pixel as indices to a UV lookup table to map the blended pixel to a CLUT index of the palettized blended image data.

Claim 11

A storage medium encoded with machine-readable computer program code for alpha-blending palettized image data, comprising: (a) means for causing a computer to provide a first set of palettized image data and a second set of palettized image data, wherein: each pixel of the palettized image data is represented by an index of a color lookup table (CLUT); and each pixel of the first set corresponds to a pixel of the second set; (b) means for causing the computer to provide a set of alpha-channel values, wherein each alpha-channel value corresponds to a pixel of the first set; (c) means for causing the computer to map each pixel of the first and second sets of palettized image data to an index space; (d) means for causing the computer to generate a set of blended pixels, wherein each blended pixel is generated from a pixel of the first set in the index space, a corresponding pixel of the second set in the index space, and a corresponding alpha-channel value; and (e) means for causing the computer to map the blended pixels back to CLUT indices to generate palettized blended image data.

Claim 12

A storage medium encoded with machine-readable computer program code for alpha-blending palettized image data, comprising: (a) means for causing a computer to provide a first set of palettized image data and a second set of palettized image data, wherein: each pixel of the palettized image data is represented by an index of a color lookup table (CLUT); and each pixel of the first set corresponds to a pixel of the second set; (b) means for causing the computer to provide a set of alpha-channel values, wherein each alpha-channel value corresponds to a pixel of the first set; (c) means for causing the computer to map each pixel of the first and second sets of palettized image data to an index space; (d) means for causing the computer to generate a set of blended pixels, wherein each blended pixel is generated from a pixel of the first set in the index space, a corresponding pixel of the second set in the index space, and a corresponding alpha-channel value; and (e) means for causing the computer to map the blended pixels back to CLUT indices to generate palettized blended image data.

Claim 13

The storage medium of claim 9, wherein the mapping of pixels by means (c) to the index space and the mapping of the blended pixels by means (e) to the CLUT indices are based on a characterized structure of the CLUT.

Claim 14

The storage medium of claim 9, wherein, for each pixel of the first set: means (c) causes the computer to map the corresponding CLUT index for the pixel to two indices in the index space; means (d) causes the computer to generate three coordinates of a blended pixel using the two indices in the index space as indices to one or more lookup tables; and means (e) causes the computer to use at least one of the coordinates of the blended pixel as an index to a lookup table to map the blended pixel to a CLUT index of the palettized blended image data.

Claim 15

The storage medium of claim 9, wherein the palettized image data is represented by CLUT indices and for each pixel of the first set: means (c) causes the computer to: (1) map the CLUT index for the pixel of the first set to a first UV index and a first Y index in the index space; and (2) map the CLUT index for the corresponding pixel of the second set to a second UV index and a second Y index in the index space; means (d) causes the computer to: (1) generate a U coordinate of a blended pixel using the first UV index as an index to a U lookup table and the second UV index as an index to the U lookup table; (2) generate a V coordinate of the blended pixel using the first UV index as an index to a V lookup table and the second UV index as an index to the V lookup table; and (3) generate a Y coordinate of the blended pixel using the first Y index and the second Y index; and means (e) causes the computer to use the U and V coordinates of the blended pixel as indices to a UV lookup table to map the blended pixel to a CLUT index of the palettized blended image data.

Claim 18

The apparatus of claim 13, wherein the mapping of pixels by the first mapper to the index space and the mapping of the blended pixels by the second mapper to the CLUT indices are based on a characterized structure of the CLUT.

Claim 19

The apparatus of claim 13, wherein, for each pixel of the first set: the first mapper maps the corresponding CLUT index for the pixel to two indices in the index space; the blender generates three coordinates of a blended pixel using the two indices in the index space as indices to one or more lookup tables; and the second mapper uses at least one of the coordinates of the blended pixel as an index to a lookup table to map the blended pixel to a CLUT index of the palettized blended image data.

Claim 20

The apparatus of claim 13, wherein the palettized image data is represented by CLUT indices and for each pixel of the first set: the first mapper: (1) maps the CLUT index for the pixel of the first set to a first UV index and a first Y index in the index space; and (2) maps the CLUT index for the corresponding pixel of the second set to a second UV index and a second Y index in the index space; the blender: (1) generates a U coordinate of a blended pixel using the first UV index as an index to a U lookup table and the second UV index as an index to the U lookup table; (2) generates a V coordinate of the blended pixel using the first UV index as an index to a V lookup table and the second UV index as an index to the V lookup table; and (3) generates a Y coordinate of the blended pixel using the first Y index and the second Y index; and the second mapper uses the U and V coordinates of the blended pixel as indices to a UV lookup table to map the blended pixel to a CLUT index of the palettized blended image data.