Image watermarking using a dynamically weighted fuzzy c-means algorithm

Abstract

Digital watermarking has received extensive attention as a new method of protecting multimedia content from unauthorized copying. In this paper, we present a nonblind watermarking system using a proposed dynamically weighted fuzzy c-means (DWFCM) technique combined with discrete wavelet transform (DWT), discrete cosine transform (DCT), and singular value decomposition (SVD) techniques for copyright protection. The proposed scheme efficiently selects blocks in which the watermark is embedded using new membership values of DWFCM as the embedding strength. We evaluated the proposed algorithm in terms of robustness against various watermarking attacks and imperceptibility compared to other algorithms [DWT-DCT-based and DCT- fuzzy c-means (FCM)-based algorithms]. Experimental results indicate that the proposed algorithm outperforms other algorithms in terms of robustness against several types of attacks, such as noise addition (Gaussian noise, salt and pepper noise), rotation, Gaussian low-pass filtering, mean filtering, median filtering, Gaussian blur, image sharpening, histogram equalization, and JPEG compression. In addition, the proposed algorithm achieves higher values of peak signal-to-noise ratio (approximately 49 dB) and lower values of measure-singular value decomposition (5.8 to 6.6) than other algorithms.