Researches on uniform meaningful watermark

As an effective way to protect copyright information, digital watermarking has been developed in many countries. The former watermarking is pseudo-random sequence that can´t label the author´s information. In this paper, we try a new method to deal with meaningful watermark such as string and logo. It uses spread spectrum technique and takes wavelet-packet transform instead of pyramid wavelet transform. The experiments show that it can carry more information and is more robust than traditional methods.