An improved wavelet-tree watermarking scheme

Abstract

This paper presents an improved wavelet-tree watermarking scheme for copyright protection. We decompose an image into four-level subbands and group the subband coefficients into many wavelet-trees. The N-bit watermark is embedded into the first N shuffled trees. An improved scheme based on changing only one coefficient of each tree is proposed to embed a watermark bit. Compared with the previous wavelet-tree watermarking scheme, the proposed scheme not only can improve the image quality but also can speed up the execution of watermark embedding. Experimental results are shown to demonstrate the effectiveness of the proposed scheme.