Multi-color image encoding apparatus and method, multi-color image decoding apparatus and method

A multi-color image encoding apparatus comprising:

• prediction means, having a color order table in which a color order of each color symbol is established, for reading and outputting the color order of the color symbol corresponding to target color pixel data to which an index code consisting of a plurality of bits is attached from the color order table;
• perimeter pixel generation means for outputting two-dimensional perimeter pixel data for the target color pixel data based on the input color pixel data;
• entropy encoding means for transforming the color order data and outputting encoding data, wherein the color order table is created by combining a two-dimensional color order table that establishes the color order for the color symbols of each pixel of said two-dimensional perimeter pixel data, the color orders being used as upper color orders, and a one-dimensional color order table for lower color orders that establishes a predetermined number of color orders for the color symbols corresponding to the color pixel data that is input ahead of the target color pixel data, the combined color order table being generated by creating a latest appearance table that moves the color order of the color symbols corresponding to the color pixel data most recently input to an uppermost line, wherein when color symbols in the two-dimensional color order table overlap color symbols in the one-dimensional color order table, the overlapped color symbols are not deleted from the one-dimensional color table;
• and
• strip creation means for partitioning the target image into strips with a horizontal width consisting of a limited number of pixels, wherein each of the strips is successively encoded.

A multi-color image encoding method comprising:

• a prediction step of reading and outputting a color order of a color symbol corresponding to target color pixel data to which an index code consisting of a plurality of bits is attached from a color order table;
• a perimeter pixel generation step for outputting two-dimensional perimeter pixel data for the target color pixel data based on input color pixel data;
• an entropy encoding step for transforming the color order data and outputting encoding data, wherein the color order table is created by combining a two-dimensional color order table that establishes the color order for the color symbols of each pixel of said two-dimensional perimeter pixel data, the color orders being used as upper color orders, and a one-dimensional color order table for lower color orders that establishes a predetermined number of color orders for the color symbols corresponding to the color pixel data that is input ahead of the target color pixel data, the combined color order table being generated by creating a latest appearance table that moves the color order of the color symbols corresponding to the color pixel data most recently input to an uppermost line;
• and
• a strip creation step for partitioning the target image into strips having a horizontal width consisting of a limited number of pixels, wherein each of the strips is successively encoded.

A multi-color image encoding method comprising:

• a prediction step for reading and outputting a color order of a color symbol corresponding to target color pixel data to which an index code consisting of a plurality of bits is attached from a color order table;
• a perimeter pixel generation step for outputting two-dimensional perimeter pixel data for the target color pixel data based on input color pixel data;
• an entropy encoding step for transforming the color order data and outputting encoding data, wherein the color order table is created by combining a two-dimensional color order table that establishes the color order for the color symbols of each pixel of said two-dimensional perimeter pixel data, the color orders being used as upper color orders, and a one-dimensional color order table for lower color orders that establishes a predetermined number of color orders for the color symbols corresponding to the color pixel data that is input ahead of the target color pixel data, the combined color order table being generated by creating a latest appearance table that moves the color order of the color symbols corresponding to the color pixel data most recently input to an uppermost line, wherein when color symbols in the two-dimensional color order table overlap color symbols in the one-dimensional color order table, then the overlapped color symbols are not deleted from the one-dimensional color table;
• and
• a strip creation step for partitioning the target image into strips having a horizontal width consisting of a limited number of pixels, wherein each of the strips is successively encoded.

A multi-color image decoding apparatus comprising:

• entropy decoding means for transforming and outputting input target encoding data as color order data;
• prediction means, having a color order table in which a color order of each color symbol is established, for reading from the color order table and outputting color symbols corresponding to the target color pixel data composed of a plurality of bits;
• perimeter pixel generation means for outputting two-dimensional perimeter pixel data for the target color pixel data based on the color pixel data being decoded, wherein the color order table is created by combining a two-dimensional color order table which establishes the color order for the color symbols of each pixel of said two-dimensional perimeter pixel data and a one-dimensional color order table for lower color orders that establishes a predetermined number of color orders for the color symbols corresponding to the color pixel data which is output ahead of the target color pixel data, the combined color order table being generated by creating a latest appearance table that moves the color order of color symbols specified by the color order most recently input to an uppermost line, and the target encoding data is decoded and output as color pixel data using the color order data corresponding to the target encoding data;
• and
• strip combination means for partitioning and decoding the target image into strips with a horizontal width having a limited number of pixels, the target image being decoded successively in strips.

A multi-color image decoding apparatus comprising:

• entropy decoding means for transforming and outputting target encoding data as color order data;
• prediction means, having a color order table in which the color order of each color symbol is established, for reading from the color order table and outputting color symbols corresponding to the target color pixel data composed of a plurality of bits;
• perimeter pixel generation means for outputting two-dimensional perimeter pixel data for the target color pixel data based on the color pixel data being decoded, wherein the color order table is created by combining a two-dimensional color order table that establishes the color order for the color symbols of each pixel of said two-dimensional perimeter pixel data and a one-dimensional color order table for lower color orders that establishes a predetermined number of color orders for the color symbols corresponding to the color pixel data which is output ahead of the target color pixel data, the combined color order table being generated by creating a latest appearance table that moves the color order of color symbols specified by the color order most recently input to an uppermost line, and the target encoding data is decoded and output as color pixel data using the color order data corresponding to the target encoding data, wherein when color symbols in the two-dimensional color order table overlap color symbols in the one-dimensional color order table, the overlapped color symbols are not deleted from the one-dimensional color table;
• and
• strip combination means for partitioning and decoding the target image into strips with a horizontal width consisting of a limited number of pixels, the target image being decoded successively in strips.

A multi-color image decoding method comprising:

• a entropy decoding step for transforming and outputting input target encoding data as color order data;
• a prediction step for reading from a color order table and outputting color symbols corresponding to the target color pixel data composed of a plurality of bits;
• perimeter pixel generation step for outputting two-dimensional perimeter pixel data for the target color pixel data based on the color pixel data being decoded, wherein the color order table is created by combining a two-dimensional color order table that establishes the color order for the color symbols of each pixel of said two-dimensional perimeter pixel data and a one-dimensional color order table for lower color orders that establishes a predetermined number of color orders for the color symbols corresponding to the color pixel data that is output ahead of the target color pixel data, the combined color order table being generated by creating a latest appearance table that moves the color order of color symbols specified by the color order most recently input to an uppermost line, and the target encoding data is decoded and output as color pixel data using the color order data corresponding to the target encoding data;
• and
• a strip combination step for partitioning and decoding the target image into strips with a horizontal width consisting of a limited number of pixels, wherein the target image is decoded successively in strips.

A multi-color image decoding method comprising:

• an entropy decoding step for transforming and outputting input target encoding data as color order data;
• a prediction step for reading from a color order table color and outputting symbols corresponding to the target color pixel data composed of a plurality of bits;
• a perimeter pixel generation step for outputting two-dimensional perimeter pixel data for the target color pixel data based on the color pixel data being decoded, wherein the color order table is created by combining a two-dimensional color order table that establishes the color order for the color symbols of each pixel of said two-dimensional perimeter pixel data and a one-dimensional color order table for lower color orders that establishes a predetermined number of color orders for the color symbols corresponding to the color pixel data that is output ahead of the target color pixel data, the combined color order table being generated by creating a latest appearance table that moves the color order of color symbols specified by the color order most recently input to an uppermost line, and the target encoding data is decoded and output as color pixel data using the color order data corresponding to the target encoding data, wherein when color symbols in the two-dimensional color order table overlap color symbols in the one-dimensional color order table, the overlapped color symbols are not deleted from the one-dimensional color table;
• and
• a strip combination step for partitioning and decoding the target image into strips with a horizontal width consisting of a limited number of pixels, wherein the target image is decoded successively in strips.