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| ¡¡ Robust Watermarking Algorithm Based on
Classification and Selection Mechanism Abstract£ºFocusing on the problem that the watermarking algorithm using mean filtering
to calculate side information can cause visible image distortions in some edge blocks£¬
an algorithm based on classification and selection mechanism was proposed through
analyzing the characteristics of mean filtering and edge blocks£¬ in which the blocks
with size 8¡Á8 pixels were classified into edge or nonª²edge blocks£¬ then the blocks
that were unsuitable for embedding watermark in edge blocks were excluded according to the
mean values of chosen low frequency coefficients of discrete cosine transformation (DCT)
for each block£® Moreover£¬ the length of meanª²filter window function was increased so
that the DCT coefficients were modified as less as possible£¬thus an improved rule for
embedding watermark was obtained£® Experimental results indicate that the proposed
algorithm has better imperceptibility and higher robustness against many kinds of common
attacks£® The average normalized correlation value between the extracted and the original
watermarks can be increased by 0ª±205 when the quality factor of JPEG compression is
equal to 20£® |
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