Patent ID: 6608865
Filing Date: 2003-08-19
Classification: H04N

Abstract:
A method of coding individual frames in a video signal comprising the steps of:performing an edge extraction upon the entire frame; coding any extracted edges by starting coordinate, one of a predetermined plurality of directions and length; dividing the frame into a plurality of blocks; classifying each of said plurality of blocks into one of a plurality of categories, the plurality of categories including a first category of blocks including no extracted edges, a plurality of second categories of blocks having one extracted edge and a corresponding one of said predetermined plurality of directions and a third category of blocks including more than one extracted edge; converting each block from spatial domain pixels into the DCT coefficients via a Discrete Cosine Transform (DCT); providing a plurality of DCT coefficient scanning orders including a default zig-zag scanning order and a plurality of directional scanning orders, each directional scanning order corresponding to one of said predetermined plurality of directions and having an order corresponding to an expected distribution of DCT coefficients for said corresponding direction; and variable length coding said DCT coefficients of each block employing a corresponding one of said DCT coefficient scanning orders, whereby blocks classified in said first and said third categories are scanned with said default zig-zag scanning order and blocks classified in one of said second categories are scanned with a directional scanning order for said corresponding direction.