Skim encoding method for compression of a two dimensional array of data

A process of compressing a two dimensional array of data in the form of a pixel map including an array of pixels having at least one array block having a plurality of N block rows and a plurality of M block columns of the pixels, each pixel having at least one associated X-bit intensity value, the process comprising:

• (a) generating a first delta frame associated with a first pair of the block columns including first and second adjacent block columns, said first delta frame having a predetermined plurality of delta rows and N delta columns of delta bits, each said delta column forming a delta byte having said predetermined plurality of bits, each said delta row forming an N-bit row byte, wherein a highest order one of said delta rows is a sign row forming a sign byte having N sign bits;
• (b) determining a skim row of said first delta frame, said skim row being a highest order one of said delta rows less than the order of said sign row and forming a skim row byte having at least one delta bit that is different from a corresponding one of said sign bits of said sign row;
• (c) determining a first height value associated with said first delta frame, said first height value indicating a number of said delta rows of said first delta frame that are lower order rows than said skim row;
• (d) generating a second delta frame associated with a second pair of the block columns including said second block column and an adjacent third block column, said second delta frame having said predetermined plurality of delta rows and N delta columns of associated delta bits, each said delta column forming a delta byte having said predetermined plurality of bits, each said delta row forming an N-bit row byte, wherein a highest order one of said delta rows is a sign row forming a sign byte having N sign bits;
• (e) determining a skim row of said second delta frame, said skim row being a highest order one of said delta rows of said second delta frame less than the order of said sign row and forming a skim row byte having at least one delta bit that is different from a corresponding one of said sign bits of said sign row of said second delta frame;
• (f) determining a second height value associated with said second delta frame, said second height value indicating a number of delta rows of said second delta frame that are lower order rows than said skim row;
• (g) determining a height difference value between said first and second height values;
• (h) determining a Huffman code value associated with said first delta frame based on at least one of said height difference value and said skim row byte of said first delta frame;
• and
• (i) performing steps corresponding to steps (d) through (h) for each subsequent one of the block columns to develop compressed data including said Huffman code values.

A process of compressing a two dimensional array of data in the form of a pixel map including an array of pixels having at least one array block having a plurality of N block rows and a plurality of M block columns of the pixels, each pixel having at least one associated X-bit intensity value, the process comprising:

• (a) generating a first delta frame associated with a first pair of the block columns including first and second adjacent block columns, said first delta frame having a predetermined plurality of delta rows and N delta columns of delta bits, each said delta column forming a delta byte having said predetermined plurality of bits and being indicative of a difference between the intensity values of a corresponding adjacent pair of pixels disposed in a corresponding one of the block rows and in said first and second block columns, each said delta row forming an N-bit row byte, wherein a highest order one of said delta rows is a sign row forming a sign byte having N sign bits each being associated with a corresponding one of said adjacent pairs of pixels and indicating whether the difference between the intensity values of said corresponding adjacent pair of pixels is positive or negative;
• (b) determining a skim row of said first delta frame, said skim row being a highest order one of said delta rows less than the order of said sign row which forms a skim row byte having at least one delta bit that is different from a corresponding one of said sign bits of said sign row;
• (c) determining a first height value associated with said first delta frame, said first height value indicating a number of said delta rows of said first delta frame that are lower order rows than said skim row;
• (d) generating a second delta frame associated with a second pair of the block columns including said second block column and an adjacent third block column, said second delta frame having said predetermined plurality of delta rows and N delta columns of associated delta bits, each said delta column forming a delta byte having said predetermined plurality of bits and being determined based at least in part on a difference between the intensity values of a corresponding adjacent pair of pixels disposed in a corresponding one of the block rows and in said second and third block columns, each said delta row forming an N-bit row byte, wherein a highest order one of said delta rows is a sign row forming a sign byte having N sign bits each being associated with a corresponding one of said adjacent pairs of pixels and indicating whether the difference between the intensity values of said corresponding adjacent pair of pixels is positive or negative;
• (e) determining a skim row of said second delta frame, said skim row being a highest order one of said delta rows of said second delta frame less than the order of said sign row which forms a skim row byte having at least one delta bit that is different from a corresponding one of said sign bits of said sign row of said second delta frame;
• (f) determining a second height value associated with said second delta frame, said second height value indicating a number of delta rows of said second delta frame that are lower order rows than said skim row;
• (g) determining a height difference value between said first and second height values;
• (h) determining a Huffman code value associated with said first delta frame based on at least one of said height difference value and said skim row byte of said first delta frame;
• and
• (i) performing steps corresponding to steps (d) through (h) for each subsequent one of the block columns to develop compressed data including said Huffman code values.

A machine readable storage device having stored therein encoding instructions for executing a process of compressing a two dimensional array of data in the form of a pixel map including an array of pixels having at least one array block having a plurality of block rows and a plurality of block columns of the pixels, each pixel having at least one associated intensity value, comprising:

• generating a delta frame associated with a pair of the block columns, said delta frame having a plurality of delta rows and delta columns of delta bits, one of said delta rows being a highest order row;
• determining a number of duplicate ones of said delta rows, each of said duplicate rows forming an identical row byte value having delta bits which have a predetermined relationship with the delta bits of said highest order row;
• recording information indicative of said number of duplicate rows;
• and
• developing compressed data including said information indicative of said number of duplicate rows of said delta frame.

A system for compressing a two dimensional array of data in the form of a pixel map including an array of pixels having at least one array block having a plurality of block rows and a plurality of block columns of the pixels, each pixel having at least one associated intensity value, comprising:

• means for generating a delta frame associated with a pair of the block columns, said delta frame having a plurality of delta rows and delta columns of delta bits, one of said delta rows being a highest order row;
• means for determining a number of duplicate ones of said delta rows, each of said duplicate rows forming an identical row byte value having delta bits which have a predetermined relationship with the delta bits of said highest order row;
• means for recording information indicative of said number of duplicate rows;
• and
• means for developing compressed data including said information indicative of said number of duplicate rows of said delta frame.