基于分块的DCT域和DWT域的双水印算法改进

摘要

Single watermarking algorithm in image protection function is single, dual watermarking algorithm proposed in this paper DCT discrete cosine transform and discrete wavelet transform DWT based on a combination of sub-blocks. Wavelet domain watermarking algorithm based on human vision system HVS image decomposition, have robust, can be used as image copyright protection; block-based discrete cosine transform watermarking algorithm less robust but block positioning can be used to image integrity finds. After the attack to test the algorithm DCT domain watermarking can resist interference in general, integrity authentication of digital images, and when subjected to malicious attacks may reflect the image is tampering;and DWT domain watermark has good resistance to malicious attacks.%单水印算法在图像保护中功能较为单一，文中提出了一种基于分块的离散余弦变换 DCT和离散小波变换DWT相结合的双水印算法。小波域水印算法基于人类视觉特性HVS对图像进行分解，具有较好的鲁棒性，可作为图像版权保护；基于分块的离散余弦变换水印算法鲁棒性较差但可块定位，可用于图像完整性认定。同时，设计嵌入模型时论证了两种水印的嵌入顺序，使后嵌入的dct域水印不会对先嵌入的dwt域水印形成攻击。经攻击测试，该算法DCT域水印可较好的反映出图像被篡改情况；同时DWT域水印对恶意攻击有较好的抵抗力，能作为版权保护的有效手段。