A non-blind Watermarking Technique using Flexible Scaling Factor in Wavelet Transform

Discrete Wavelet Transformation based watermarking algorithm gives robust, secure and strong results in non-blind and semi blind applications. High coefficients are selected in wavelet transform and binary image embedded into cover image as a watermark using secret key. Most of embedding algorithms use scaling factor
$a$
which is selected by try and use method. In this work, we use flexible scaling factor in different bands of the wavelet and also 8×8 blocks of the cover image to improve performance of the watermarking. Experimental results show that block and flexible scaling factor base Wavelet watermarking gives better peak signal-to-noise ratio (PSNR) values in Lena, Barbara, peppers and cameraman images. In addition to that, extracted logo has very high similarity ratio (SR) if compared to other Wavelet algorithms. Proposed algorithm is resist against the all common type of attacks.