Digital Watermarking Technique for Protecting Digital Images
Link tải luận văn miễn phí cho ae Kết nối [email protected] Abstract-Internet evolution, along with the advancement of digital multimedia tools have create a major impact in making the storage and distribution of multimedia content a straightforward tasks. Thus security of multimedia contents becomes a vital issue and there is a need in protecting the digital content against counterfeiting, piracy and malicious manipulations. Digital watermarking is an evolving field that requires continuous effort to find for the best possible method in protecting multimedia content. In this paper, we describe overview of digital image watermarking technique and proposed an algorithm for copy write protection of digital images in neT domain. Digital watermarking can be defined as the process of embedding a certain piece of information ,technically known as watermark into multimedia content including text documents , images, audio or video streams, such that the watermark can detected or extracted later to make an assertion about the data. We have also implemented this algorithm using MATLAB 7.x and code is also given in this paper. Keywords: Digital image watermarking, Spread-Spectrum techniques, copy Write Protection I. INTRODUCTION The recent growth of networked multimedia systems has increased the need for the protection of digital media. This is particularly important for the protection and enforcement of intellectual property rights. Digital media includes text, digital audio, images, video and software. Many approaches are available for protecting digital data; these include encryption, authentication and time stamping. One way to improve one's claim of ownership over an image, for instance, is to place a low-level signal directly into the image data. This signal, known as a digital watermark, uniquely identifies the owner and can be easily extracted from the image. Digital watermarking technology is an emerging field in computer science, cryptography, signal processing and communications. Digital Watermarking [4, 5, 6] is intended by its developers as the solution to the need to provide value added protection on top of data encryption and scrambling for content protection. Like other technology under development [7, 8], digital watermarking raises a number of essential questions as follows. • What is it? • How can a digital watermark be inserted or detected? • How robust does it need to be? • Why and when are digital watermarks necessary? • What can watermarks achieve or fail to achieve? • How should digital watermarks be used? • How can we evaluate the technology? • How useful are they, that is, what can they do for content protection in addition to or in conjunction with current copyright laws or the legal and judicial means used to resolve copyright grievances? • What are the business opportunities? • What roles can digital watermarking play in the content protection infrastructure? In this paper we present algorithms for image authentication and forgery prevention known as watermarks. Figure 1 shows the block diagram for watermarking digital images. Original Image Watermark Watermarked Image Figure 1: BlockDiagram of Watermarking Algorithm A. Types ofDigital Watermarks Watermarks and watermarking techniques can be divided into various categories in various ways. The watermarks can be applied in spatial domain. An alternative to spatial domain watermarking is frequency domain watermarking. It has been pointed out that the frequency domain methods are more robust than the spatial domain techniques. Different types of watermarks are shown in the Figure 2.