Arbitrarily shaped video object coding by wavelet

Video object coding is one of the most important functionalities proposed by MPEG4. In this paper, we propose a new wavelet method to encode the texture of an arbitrarily shaped object, both for the still and for video object. The method uses the shape adaptive wavelet transform (SA-DWT) in MPEG4 still object coding, but with a computationally more efficient lifting implementation. The transformed object coefficients are then quantized and entropy encoded with a partial bitplane embedded coder, which greatly improves the coding efficiency. We denote the coding algorithm as video object wavelet (VOW) coder. Experimental results show that VOW significantly outperforms MPEG4 in still object coding, and achieves a comparable performance in video object coding in terms of PSNR. Moreover, the VOW decoded object looks better subjectively, with less annoying blocking artifacts than that of MPEG4.