Linear list compression

A linear list compression apparatus for coding a stroke of a connected component, the stroke comprising plural substantially parallel pixel runs of the same level, the apparatus comprising:

• segmenter means for identifying the connected component object;
• graph builder means for creating a graphic representation for the connected component object segmented by said segmenter means, wherein the graphic representation includes a plurality of nodes and strokes created by said graph builder means;
• a compressor means comprising:
• means for determining a reference position of each of the strokes such that at least one pixel run can be coded relative to a reference position;
• coding means for selectively coding pixel runs of each of the strokes based on modified Huffman coding techniques in order to thereby create a coded linear list of pixel runs, the coding means coding a first pixel run relative to a reference position and coding remaining pixel runs relative to adjacent and previously coded pixel runs, wherein the coding means operates in a horizontal mode or a vertical mode only;
• and
• means for marking an end of the coded linear list when the coding means has coded all of the pixel runs of the stroke.

A linear list compression apparatus for coding one level of a bi-level image representing a connected component, the apparatus comprising:

• an image segmenter for identifying the connected component;
• a graph builder for generating a graphic representation of the connected component, the graphic representation including a plurality of nodes and strokes;
• a referencing module for identifying reference nodes from among graph nodes of each of the strokes such that at least one pixel run can be coded relative to each respective reference node;
• a coding module for successively coding pixel runs of each stroke based on modified Huffman coding techniques in order to thereby create a coded list of pixel runs for each stroke, the coding unit coding a first pixel run of each stroke relative to a respective reference node and coding remaining pixel runs of each stroke relative to adjacent and previously coded pixel runs of each stroke, wherein the coding module operates in a horizontal mode or a vertical mode;
• and
• a closing module for marking an end of each coded linear list when the coding module has coded all of the pixel runs of each stroke.