In this paper, we propose a new blind watermarking algorithm for images which is based on tree structure. The algorithm
embeds the watermark in wavelet transform domain, and the embedding positions are determined by significant
coefficients wavelets tree(SCWT) structure, which has the same idea with the embedded zero-tree wavelet (EZW)
compression technique. According to EZW concepts, we obtain coefficients that are related to each other by a tree
structure. This relationship among the wavelet coefficients allows our technique to embed more watermark data.
If the watermarked image is attacked such that the set of significant coefficients is changed, the tree structure allows the
correlation-based watermark detector to recover synchronously. The algorithm also uses a visual adaptive scheme to
insert the watermark to minimize watermark perceptibility. In addition to the watermark, a template is inserted into the
watermarked image at the same time. The template contains synchronization information, allowing the detector to
determine the geometric transformations type applied to the watermarked image. Experimental results show that the
proposed watermarking algorithm is robust against most signal processing attacks, such as JPEG compression, median
filtering, sharpening and rotating. And it is also an adaptive method which shows a good performance to find the best
areas to insert a stronger watermark.