摘要：
位置图压缩是空间域水印嵌入算法中的关键问题。为此,以提高嵌入容量为目标,提出一种基于差值位置图调整的差分扩展优化算法。考虑可扩展差值的位置分布,通过修改短连续零组提高无损压缩率,从而扩大水印净荷嵌入空间,减少嵌入总量,提高峰值信噪比。仿真实验结果表明,该算法可通过选择最佳或优选调整强度增强差分扩展算法的水印嵌入性能,水印净荷嵌入容量可提升2.48倍～5.26倍,峰值信噪比可提升4.4 dB～8 dB。
关键词:
位置图,
差分扩展,
调整强度,
水印嵌入,
信息隐藏
Abstract:
Location Map(LM) compression is the key issue of spatial domain watermark embedding.Aiming at this issue,a Difference Expansion(DE) optimization algorithm is proposed based on difference LM adjustment.Considering location distribution of extensible difference,some small continuous zero sets are all modified to acquire a lot of pure watermark payload space.Thus,difference LM is compressed more efficiently by some lossless compressors.At the same time,the quantities of embedded points are reduced and the Peak Signal to Noise Ratio(PSNR) is improved.Simulation results show that the proposed algorithm can significantly enhance the embedding performance of DE algorithm by an optimal or a preferred threshold for adjustment strength parameter.In this way,embedding Bits per Pixel(BPP) for pure payload is improved by 2.48 times to 5.26 times.Moreover,PSNR increases 4.4 dB to 8 dB.
Key words:
Location Map(LM),
Difference Expansion(DE),
adjustment strength,
watermark embedding,
information hiding
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