A Second Order Spread Spectrum Watermarking Scheme Using Multi-Threshold Wavelet Codec
Izhar Dad Khan, Salim Raza, D.A. Karras, M. Abdullah, Fatima Sajid Butt · 2006
A second order error resistant watermarking approach based on spread spectrum is presented in this research. At the heart of the proposed solution lies the concept of twice modulation of the watermark sequence and the selection of the host image coef- ficients based on the Multi-Threshold Wavelet Codec (MTWC). DSSS approach has been widely used in the communications to cover the message signal (narrow band) over the large noise signal (wide band). The resulting signal provides excellent low error probability and is hard to detect the message signal. DSSS used with error correcting codes makes it possible to recover the mes- sage even after severe signal distortions. MTW technique helps in determining the actual wavelet coefficients that need to be water- marked so that the watermark sequence is robust.