Apparatus and method for generating coded block pattern for alpha channel image and alpha channel image encoding/decoding apparatus and method using the same

摘要

Provided are an apparatus and method for generating a coded block pattern (CBP) for an alpha channel image and an apparatus and method for encoding or decoding the alpha channel image using the same. The alpha channel image encoding apparatus comprises a CBP generator generating a CBP of a first block corresponding to an encoding unit in the alpha channel image by allocating CBPs to a plurality of second blocks composing the first block; and a bitstream generator generating a bitstream by encoding the CBP or the CBP and pixel values of the second blocks based on the CBP of each of second blocks. The alpha channel image decoding apparatus comprises a bitstream analyzer analyzing and decoding a bitstream obtained by encoding an alpha channel image for each first block, which is an encoding unit; a CBP analyzer extracting and analyzing a CBP for each of second blocks included in the first block from the decoded data; and an image restorer restoring a current alpha channel image using the CBP analyzed for each of the second blocks and decoded pixel values.