Robust watermarking using extended anti-collusion codes

Design of a robust multimedia watermarking is a complex task, as there exists trade-off among robustness, perceptibility and achievable rate of reliable communications. Watermarking of digital media to get high robustness without perceptibility lost is a challenging task. In ordinary watermarking techniques it is not possible to detect the actual colluder unless the watermark signal is uniquely assigned. In the time of watermarking it is possible to assign some unique codeword to every copy to be distributed, by which it is possible to detect any alteration made to the watermarked copy. This paper presents robust watermarking with help of spread spectrum embedding methodology of a specially designed codeword. The codeword is designed from theory of Balanced Incomplete Block Design and extended by repeating its bits and block interleaved to control clustered error.