DIGITAL WATERMARKING WITH A NEW ALGORITHM

Afroja Akter, Muhammad Ahsan Ullah

Abstract: Everyday millions of data need to transmit through a distinct channel for various purposes; as a result there is a certain chance of third person interruption on that data. In this regards digital watermarking is one of the best solution. This paper proposes a new embedding algorithm (NEA) of digital watermarking. The algorithm is performed for digital image as data. The performance is compared for NEA and well established Coxs modified embedding algorithm. The watermarking is based on discrete wavelet transforms (DWT) and discrete cosine transforms (DCT). The acceptance of the new algorithm is measured by the two requirements of digital watermarking. One is imperceptibility of the watermarked image, measured by peak signal to noise ratio (PSNR) in dB; another one is robustness of the mark image, measured by correlation of original mark image and recovering mark image. Here a 512×512 gray scale "Lena" and "Cameramans" image is taken as host images, and a 128×128 gray scale image is taken as mark image for 2 level of DWT. The simulation results for different attacking conditions such as salt and pepper attack, additive white Gaussian noise (AWGN) attack, jpg compression attack, gamma attack, histogram attack, cropping attack, sharpening attack etc. After different attacks the changing tendency PSNR for both algorithms are similar. But the mean square error (MSE) value of NEA is always less than Cox’s modified algorithm, which means that after embedding the changes of the host image property lower for NEA than Cox’s algorithm. From the simulation results it can be said that NEA will be a substitute of modified Cox’s algorithm with better performance.

Keywords: Digital watermark, DWT, DCT, Cox’s modified algorithm, Lena image, Cameraman image, AWGN, JPG, salt and pepper attack, PSNR, correlation, MSE.

DOI: https://doi.org/10.15623/ijret.2014.0303039