Patent ID: 8050329

Claim:
A method for coding an input object, where said input object mask has a plurality of regions, said method comprising the steps of: (a) assigning at least one symbol to each of the plurality of regions, wherein each of the plurality of regions comprises a 2 N ×2 N block of pixels, N is equal to or greater than a desired number of object mask layers, L, and: each of the plurality of regions having only pixels with a first mask value is assigned a first symbol, each of the plurality of regions having only pixels with a second mask value is assigned a second symbol, said second symbol being different than said first symbol, and each of the plurality of regions having pixels with said first mask value and said second mask value is assigned a third symbol, said third symbol being different than said first and said second symbols; (b) coding said assigned symbols of the input object mask, wherein each of the plurality of regions assigned said first symbol or said second symbol is assigned to a first class, and each of the plurality of regions assigned said third symbol is assigned to a second class, (c) utilizing a first binary probability model to encode each of said first and second classes, and utilizing a second binary probability model to further encode said first class; (d) decomposing said input object mask into a plurality of object mask layers of different spatial resolution, wherein each object mask layer is identified as Λ n , 0≦n≦L, Λ 0 is a full resolution object mask layer, and Λ L is a base object mask layer; (e) coding, utilizing an encoder, said base object mask layer Λ L , wherein each of said plurality of regions assigned to said second class within said base object mask layer Λ L is encoded in a raster scan order; and (f) coding, utilizing said encoder, a next higher layer of said plurality of object mask layers in accordance with information from a lower object mask layer Λ n+1 .