Digital Watermarking Interim Report EE5359 Multimedia processing Under the Guidance of Dr K R Rao Submitted by Ehsan Syed 1000671971 seaquadri gmail com The University of Texas at Arlington Spring 2011 Introduction Digital watermarking is based on the science of steganography 1 or data hiding Steganography comes from the Greek meaning covered writing Steganography is defined as the practice of undetectably altering a work to embed a secret message It is an area of research of communicating in a hidden manner Introduction Steganography and watermarking rely on imperfections of human senses The human eye has a limited dynamic range so low quality images can be hidden within high quality images 2 Basic Principle There are three main stages in the watermarking process 3 generation and embedding attacks retrieval detection Generation and Embedding Generation of watermarks is an important stage of the process Watermarks contain information that must be unique otherwise the owner cannot be uniquely identified In embedding an algorithm accepts the host and the data to be embedded and produces a watermarked signal Various algorithms have been developed so far 4 13 Attacks The watermarked signal is then transmitted or stored usually transmitted to another person If this person makes a modification this is called an attack There are many possible attacks Retrieval Detection Detection is an algorithm which is applied to the attacked signal to attempt to extract the watermark from it If the signal was not modified during transmission then the watermark is still present and it can be extracted Block diagram Fig 1 Basic block diagram of digital watermarking Types of watermarking There are mainly three types of watermarking 14 Visible watermarking Invisible watermarking Dual watermarking Techniques of watermarking There are two major techniques of watermarking 15 Spatial domain slightly modifies the pixels of one or two randomly selected subsets of an image Frequency domain this technique is also called transform domain Values of certain frequencies are altered from their original Project Goals The goals of this project are to embed a watermark into an image using LSB technique compressing the watermarked image decompressing it extract the watermark from the image Program for making watermarked images host image input Enter the host image file name with extension s wmrk image input Enter watermark image file name with extension s host imread host image wmrk imread wmrk image figure 1 imshow host title Host Image figure 2 imshow wmrk title Watermark Image host double host wmrk double wmrk bits 3 wmrk shifted bitshift wmrk 8 bits for i 1 bits host bitset host i 0 end watermarked image uint8 host wmrk shifted figure 3 imshow watermarked image title Watermarked Image Host Image Results so far Watermarked images are created JPEG compression and decompression will be done in the final report Extraction of the watermark from the watermarked image will be done in the final report Watermark Image Visible Watermarked image Invisible Watermarked image References 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 L M Marnel et al Spread spectrum image steganography IEEE Transactions on Image Processing pp 10751083 Aug 1999 J J K O Ruanaidh et al Watermarking digital images for copyright protection IEE Proceedings in Vision Image and Signal Processing pp250 256 Aug 1996 I J Cox and M L Miller A review of watermarking and the importance of perceptual modeling Proceedings of Electronic Imaging February 1997 H J Wang et al Wavelet based digital image watermarking Optics Express PP 491 496 Dec 1998 P T Yu et al Digital watermarking based on neural networks for color images Signal Processing PP 663 671 Mar 2001 J O Ruanaidh et al Cryptographic copyright protection for digital images based on watermarking techniques Theoretical Computer Science pp 117 142 Sep 1999 C Fornaro and A Sanna Public key watermarking for authentication of CSG models Computer Aided design pp 727 735 Oct 2000 M Barni et al Copyright protection of digital images by embedded unperceivable marks Image and Vision Computing pp897 906 Aug 1998 J R Hernandez et al Improving the performance of spatial watermarking of images using channel coding Signal Processing pp 1261 1279 July 2000 S Pereira et al Optimal transform domain watermark embedding via linear programming Signal Processing pp 1251 1260 July 2001 F Perez Gonzalez et al Approaching the capacity limit in image watermarking a perspective on coding techniques for data hiding applications Signal Processing pp 1215 1238 July 2001 R Baitello et al From watermark detection to watermark decoding a PPM approach Signal Processing pp 1261 1271 July 2001 M Barni et al A DCT domain system for robust image watermarking Signal Processing pp 357 372 May 1998 S P Mohanty et al A Dual Watermarking Technique for images Proceedings of the seventh ACM international conference on Multimedia pp 49 51 1999 F Hartung and M Kutter Multimedia watermarking techniques Proceedings of the IEEE Vol 87 No 7 pp 1079 1107 July 1999
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