8204

7602

كارشناسي ارشد

معماري كامپيوتر

اصفهان: دانشگاه صنعتي اصفهان، دانشكده برق و كامپيوتر

1392

ده،130ص.: مصور،جدول، نمودار

ص.ع.به فارسي و انگليسي

شادرخ سماوي

نادر كريمي

10/9/92

محمدرضا احمدزاده، مسعود عمومي

مهندسي برق و كامپيوتر

ID7602

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Robust Adaptive Watermarking and Accelerating Contourlet Transform Shekoofeh Azizi s azizi@ec iut ac ir Date of Submission 2013 10 01 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor S Samavi Prof samavi96@cc iut ac irAbstract In Due to increasing use of computer networks and Internet digital contents can nowadays be easilyexchanged As a result many copyrighted contents may be shared illegally and this has concernedmultimedia owners In order to overcome this problem watermarking schemes have been proposed toprotect copyright of digital contents such as digital images in spatial and transform domains Transformdomain methods have attracted more attention because they are more robust against possible attacks Robustness and visual quality are two conflicting features that should be attained at the same time in aproper watermarking scheme Obtaining these features require high computational complexity whichmakes it inappropriate for use in many real time watermarking applications Therefore improving thecomputational complexity of complicated watermarking techniques by decreasing execution time hasbecome a challenge In this thesis after presenting watermarking concepts and applications based oncharacteristics of watermarking and potential of parallelism watermarking schemes in spatial and transformdomains are reviewed and classified Then a new image adaptive watermarking framework is introducedand based on this framework three robust watermarking schemes are proposed All of the proposedwatermarking algorithms are blind methods which embed binary logos as watermark in cover images These methods properly adjust the strength factor while maintain visual quality of image Experimentalresults verify this fact and show that proposed schemes have good robustness against usual imageprocessing attacks while preserving fidelity of watermarked images From another point of view thisproblem could take advantage of modern GPUs properties such as high computational intensity availability and low cost For this purpose after eliminating details of these algorithms parts withparallelism capability are determined and reshaped for parallel processing and acceleration Contourlet Transform CT as a widespread transform with high computational complexity in watermarking is selectedfor parallel execution Experimental results show that with existing GPUs CT execution achieves aspeedup more than 20x as compared to its non parallel CPU based method It takes approximately 40ms tocompute the transform of a 512 512 image which is almost sufficient for real time applications Keywords Watermark adaptive watermarking robustness Imperciptibility GPU parallesim

شادرخ سماوي

نادر كريمي

محمدرضا احمدزاده، مسعود عمومي