期刊名称：Journal of Theoretical and Applied Information Technology
印刷版ISSN：1992-8645
电子版ISSN：1817-3195
出版年度：2015
卷号：81
期号：3
出版社：Journal of Theoretical and Applied
摘要：Digital image watermarking is mainly used in copyright protection. We propose block based approach for watermarking images with their own ROI. The algorithm divides the image into 8x8 blocks. DWT transform is applied on each block. The extracted LL of the computed DWT is obtained and DCT is applied on LL to obtain LL-DCT coefficients. The watermark is embedded by changing the sign of LL-DCT coefficients of each block. In this paper we study the block perturbation properties, we found that the block embedding index is inversely proportional to watermark robustness; in addition we found that single 8x8 block can optimally hold single bit by changing the sign of the medium LL-DCT coefficient.
关键词：Image Watermarking; Discrete Cosine Transform; Discrete Wavelet Transform; Region of Interest; Embedding; Extraction; Human Visual System.
