A hybrid digital image watermarking algorithm based on DCT-DWT and auto-thresholding

摘要

Multimedia evolution in the current era has given digital images security and privacy a great concern. Digital image watermarking is used to produce highly protected images in order to promote secure and protected exchange over the network and between individuals. In this paper, a robust algorithm for digital image watermarking is proposed based on a hybrid watermarking and auto-thresholding. This algorithm is designed to embed the watermarks in the transform domain using both discrete cosine transform and discrete wavelet transform (DCT-DWT). Image is transformed to DCT then to DWT and the algorithm trains itself to choose the best embedding threshold. This threshold must satisfy a performance trade-off and at the same time attains high imperceptibility and robustness. The algorithm performance is evaluated under various attacks and showed high-performance level. Imperceptibility evaluation showed peak signal-to-noise ratio above 42.96 dB and similarity percentage above 99.27%. The algorithm proved high resistance to noising, scaling, cropping, rotation, and compression attacks. Copyright (C) 2015 John Wiley & Sons, Ltd.