Method and apparatus for block based image compression with multiple non-uniform block encodings
Embodiments of the present invention are directed to a method and apparatus for block based image compression with multiple non-uniform block encodings. In one embodiment, an image is divided into blocks of pixels. In one embodiment the blocks are four pixels by four pixels, but other block sizes are used in other embodiments. In one embodiment, a block of pixels in the original image is compressed using two different methods to produce a first and second compressed block. Thus, each block in the original image is represented by two, typically different, compressed blocks. In one embodiment, color associated with a pixel is determined by combining the compressed information about the pixel in the first compressed block with information about the pixel in the second compressed block. In another embodiment, global information about the image is combined with the information in the first and second compressed blocks.
1. A method adapted for use in an image compression apparatus to compress an input image comprising a plurality of pixels, the method comprising:
partitioning said input image into a plurality of original blocks, each comprising a selected subset of the pixels comprising said input image;
compressing each of said blocks to generate a respective one of a plurality of compressed blocks;
combining all of said plurality of compressed blocks to generate an output image; and wherein
each of said plurality of compressed blocks includes a projection value based on a vector.
2. The method of claim 1 wherein the value based on the projection vector comprises a magnitude representing a magnitude of an original block projected onto said projection vector.
3. The method of claim 2 wherein the projection vector comprises a unit length.
4. An image compression apparatus for use in image compression, the apparatus comprising:
a receiver adapted to receive an image;
a decomposer device, said decomposer device adapted to:
decompose said received image into a plurality of original blocks and compress each of said plurality of blocks into a respective plurality of compressed blocks;
project each of said plurality of original blocks onto a vector to generate a new block storing a magnitude of the projection; and
an output to output an output block based on said compressed blocked and said new block storing magnitude of the projection.
5. A computer readable medium storing non-transitory code that when executed by one or more processors causes the one or more processors to generate a data format comprising:
a first portion representing a vector;
a second portion representing color points; and
a third portion representing indices to map to colors generated from or represented by said second portion.
6. An image compression system comprising:
logic operative to compress an original image block having a pixel set by generating:
a color portion comprising at least first and second color map;
an index portion comprising at least first and second indices, said first index associated with at least said first color map and said second index associated with said second color map;
said first index generated based on at least said first color map to approximate colors in a first portion of said original image block and said second index generated based on at least said second color map to approximate colors in a second portion of said original image block; and
wherein the logic is operative to provide the color portion and the index portion as compressed data for the image block.
7. An image compression system comprising:
logic operative to compress an original image block having a pixel set wherein the logic is operative to generate:
a first portion of said original image block represented by a first color portion and a first index associated with and generated based on said first color portion; and
a second portion of said original image block represented by a second color portion and a second index associated with and generated based on said color portion; and
wherein the logic is operative to provide the first and second indexes and first and second color portions as compressed data for the image block.