Abstract:
As a potential solution to defend
unauthorized replication of digital multimedia
objects, digital watermarking technology is now
attracting significant attention. With a combination of
Lifting Wavelet Transform (LWT) and Discrete
Cosine Transform (DCT), the system is presented. Key
sequences used for watermark embedding and
extraction are generated by Linear Congruential
Generator (LCG). Moreover, for the sake of security
enhancement, double coded image puzzling method is
created. The LWT is applied to decompose the
original image into four sub-band images. Then the
DCT is computed on the selected sub-band of the LWT
coefficients. The watermark bits are modified by LCG
and embedded in the DCT transformed of the selected
LWT sub-band of the original image. The Doublecoded
image puzzling is created in order not to
recognize the meaningful image by illegal users. The
proposed system mainly focuses on an invisible
watermark embedding, imperceptibility of
watermarked image, blind watermarking by using key
sequence instead of using original image, and
robustness for watermark extraction. The presented
system is realized in MATLAB.
