Image Watermarking using Hybrid IWT-DCT Method and Chaotic maps

Today technology allows the distribution of digital images quickly and easily, so it is important to protect copyrights in multimedia files. Watermarking techniques are commonly used for copyright protection. However, it is still a challenge to achieve the imperceptibility of the watermark and its robustness against various attacks. In the present work, a non-blind watermarking method based on the integer wavelet transform (IWT) and the discrete cosine transform (DCT) is proposed with the aim of improving robustness and imperceptibility. The watermark image is encrypted by Arnold's chaotic map beforebeing inserted by scrambling the pixels to offer additional security. The results demonstrate good quality in the cover image (۳۸ dB), as well as the recovered watermark image (۳۵ dB) and robustness against attacks such as JPEG compression, salt and pepper noise, rescaling, sharpening and cropping.