Even-length biorthogonal wavelets for digital watermarking

In wavelet based digital watermarking, when the particular wavelet filter used forms part of a secret key, the diversity and size of a family of filters contributes to the level of security. Diversity has been shown to improve the security of watermarking systems from hostile attacks. This paper presents a family of even length biorthogonal wavelet filters for use in digital watermarking. The filters are explicitly parameterized by two free parameters and can provide further diversity in watermarking. The filters have a prescribed number of vanishing moments ensuring some degree of smoothness in the resulting wavelet function. The study is conducted in the context of a blind watermarking scheme and the robustness of the filters to range of attacks is evaluated. © 2005 IEEE.