Compression enhancement in graphics system

A compression enhancement arrangement for graphics systems, said arrangement comprising:

• detecting means for detecting high frequency regions of an image, comprising said high frequency regions and low frequency regions, in which compression artifacts are likely to be produced and deeming those regions as selected regions;
• storage means for maintaining a record of said selected regions;
• and
• restoring means for, after lossy compression of said image and subsequent expansion of said compressed image, manipulating the expanded selected regions based on said record to reduce the visual impact of any produced compression artifacts by resetting the colour of a pixel, for each pixel within the expanded selected regions, to a colour of a first predetermined set of colours closest to the previous colour of the pixel.

A graphics system including:

• compressor/expander means for lossy compressing image data, comprising high frequency regions and low frequency regions, and for expanding compressed image data, wherein said compressor/expander means permits the storage of compressed image data;
• and
• a compression enhancement arrangement coupled to said compressor/expander means, said arrangement comprising:
• detecting means for detecting said high frequency regions of image data in which compression artifacts are likely to be produced and deeming those regions as selected regions;
• storage mans for, after lossy compression of said image data and subsequent expansion of said compressed image data, manipulating the expanded selected regions based on said record to reduce the visual impact of any produced compression artifacts by resetting the colour of a pixel, for each pixel within the expanded selected regions, to a colour of a first predetermined set of colours closest to the previous colour of the pixel.

A graphics system comprising:

• a host processor for generating and instructing manipulations of image data comprising high frequency regions and low frequency regions;
• compression and expansion means interconnected with a main storage means for lossy compressing said image data prior to storage in said main storage means and for expanding said compressed image data upon retrieval from said main storage means;
• a compression enhancement arrangement comprising:
• detecting means for detecting said high frequency regions of said image data in which compression artifacts are likely to be produced and for deeming said regions as selected regions;
• record means for maintaining a record of said selected regions;
• restoring means for, after compression and subsequent expansion of said image data, manipulating the expanded selected regions based on said record to reduce the visual impact of any produced compression artifacts by resetting the colour of a pixel, for each pixel within the expanded selected regions, to a colour of a first predetermined set of colours closest to the previous colour of the pixel;
• and
• display means for displaying said image data.