جستجوی مقالات مرتبط با کلیدواژه "توسعه های تبدیل موجک" در نشریات گروه "فناوری اطلاعات"

With advance of technology, manipulation and distribution of digital media such as image, audio and video has been widespread explosively. This causes problems like unauthorized copy being more important. Watermarking is a method for copyright protection and hidden information transfer. Wavelet transform has good functionality in various watermarking methods because of its good ability of modeling human visual system. Wavelet transform extensions like basic wavelet are utilized in variety applications of image processing and good results have been reported from them. No comprehensive research has been done in efficiency of extended wavelets on watermarking robustness. In this paper efficiency of wavelet transform extensions is investigated in different attacks. For this purpose a general framework is proposed for embedding and watermark extraction based on bidiagonal singular value factorization. Results show classic wavelets have good robustness against attacks like compression and noises, but they have less robustness against geometric attacks such as rotation and shearing. Unlike classic wavelets, multidirectional wavelet extensions are robust in geometrical attacks.