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Watermark Extraction Methods For Linearly Distorted Images to Maximize Signal-to-Noise Ratio Brandon Migdal May 7 th 2004 Rochester Institute of Technology Advisor: Dr. Carl Salvaggio. Outline. Embedding Process Research Extraction Process Results Future Work. Embedding Process. 100101….
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Watermark Extraction Methods For Linearly Distorted Images to Maximize Signal-to-Noise RatioBrandon MigdalMay 7th 2004Rochester Institute of TechnologyAdvisor: Dr. Carl Salvaggio
Outline • Embedding Process • Research • Extraction Process • Results • Future Work
Embedding Process 100101… Initial Image Carrier Message FFT FFT Multiplication Inverse FFT + Scale Amplitude Zero Mean
Template Design • Considerations • Location Design • Reasons
Embedding Process 100101… Initial Image Carrier Message FFT FFT Multiplication Inverse FFT + Scale Amplitude Zero Mean
Carrier Design • Random Phase • Generated Pseudo-Random • Scale based on Nyquist, and CSF • Reasons
Research Areas • Windowing • Subsetting
Windowing FFT Windowing Technique Substitute Into Level 3 Extraction Process
Subset Level 3 Extraction Process + Subsetting
Extraction Process Level 3 Extraction Level 2 Extraction Level 1 Extraction Binary Message Image Information & SNR FFT FFT Comparison Scaling Factor Cross Correlation FFT-1 X Embedded Image Cross Correlation Image Information FFT Blurring Filter + SNR Extraction Scaling Factor Average Image Block X Divided by Total Number of Image Blocks For All Image Blocks
Future Work • Windowing • Subsetting
Reference Material • Gonzalez, R., and R. Woods, Digital Image Processing, Second Edition, 2002, New Jersey: Prentice Hall • Rabbani, M., and C. Honsinger, Data Embedding Using Phase Dispersion, IEE Seminar on Secure Images and Image Authentication Ref. No.00/039, 2000, Volume 5, pp. 1-7 • Xie, H. N. Hicksa, G. Kellera, H. Huangb, and V. Kreinovich, An IDL/ENVI implementation of the FFTbased algorithm for automatic image registration, Computers & Geosciences, 2003, Volume 29, pp. 1045–1055 • Signal-to-Noise Calculations, January 2004, http://emalwww.engin.umich.edu/emal/courses/SEM_lectureC W/SEM_SignalNoise.html