Patent ID: 6977738

Claim:
A data compression method for compound document data, the method comprising: receiving a first data set representing a compound document page including both an alphanumeric text data subset and at least one image data subset; extracting the image data subset; compression-enhancement-filtering the image data subset and outputting a filtered image date subset; recombining the filtered image data subset with the alphanumeric text data, forming a second data set; rasterizing the second data set and outputting a third data set of rasterized page description data; compressing the rasterized page description data by retaining individual pixel image data values for each recorded pixel color value of the color image raster data set that is different from both a preceding row, same column, pixel and a horizontally adjacent, same row, preceding pixel; for each retained pixel image data value, encoding individual pixel image data values for pixels in a current pixel row with replacement data strings by replacing pixel image data values for current pixels in a current pixel row with replacement byte strings wherein the byte strings are structured in the form of a Command field and a Data field, wherein the replacement data strings include a replacement positioning code and a replacement count code for replicating retained pixel image data values for subsequent raster data decompression as a group of substantially identical color value pixels; and outputting a fourth set of compressed rasterized page description data.