关键词: 数字水印 LDPC码 DCT

Abstract:

Based on the similarity between digital watermarking systems and the communication transform system model, a watermarking algorithm for digital images  that adopts low-density parity-check （LDPC） coding techniques is investigated in this paper. LDPC codes are used to provide error protection against  attacks in the watermarking channel. The encoded watermark by the LDPC encoder is embedded in the discrete cosine transform （DCT） domain of the origi inal image, and then retrieved from the watermarked image using the LDPC iterative method. Simulation results show that the proposed algorithm can succe ssfully decrease the bit error rate of the retrieved watermark and enhance robustness and invisibility.

Key words: （Digital Watermark, LDPC code, DCT）