Engineering and Technology Journal

Abstract

Digital watermarking has been developed to protect digital images from
illegal manipulation. Discrete wavelet Transform (DWT) and Discrete Cosine Transform (DCT) are techniques used for digital watermarking. A combination of DWT and DCT techniques are used in this paper to meet imperceptibility, robustness and security requirements. Peak Signal to Noise Ratio (PSNR) and Bit Correct Ratio (BCR) measurements are used to study the effect of parameters: gain factor, threshold value, sub band, and image size on the watermark image. Many images are used to
embed the watermark image and the effects of parameters on the extracted
watermark image are studied. Then the optimal parameter values has been
specified.