ColorImage Watermarking Based on DS-CDMA
Oh‐Jin Kwon · 2008
Forgraylevel images, watermarking algorithms basedon imagenormalization andDS-CDMA havebeen proposed. In DS-CDMA method,a binarypseudo-random sequence isgenerated andembeddedasawatermark. Inthe extracted binary pseudo-random sequence, wemayseethenon- zeroBitErrorRate(BER)evenifthewatermarked imagehas notbeenattacked. We extend this methodtocolor images. The Hadamardkernel isusedforimproving theBER against no attack. Experimental results showthatourmethodguarantees thezeroBER against no attack andtherobustness against commonimageprocessing attacks suchasJPEGcompression, cropping, scaling, histogram equalization, changing luminance andcontrast, etc.