Extracted Image Quality Improvement Algorithm Using Hybrid Digital Watermarking

Abstract

The proposed model makes changes in existing algorithm by boosting alpha values in an algorithm involving use of hybrid watermarking techniques like Discrete Cosine Transform (DCT), Discrete Wavelet Transform (DWT), and Singular Value Decomposition (SVD) to enhance efficiency and accuracy in watermark embedding and extraction. As DC coefficients are perceptually most significant and more robust to many unintentional attacks (signal processing) and intentional attacks (unauthorized removal), in this paper we use existing algorithm, but we intend to make new algorithm that will be blind, which means cover object may not be present at receiver’s end for extracting watermark. The second intension is to make the system more robust to almost all attacks including rotation attack, than the existing algorithm. Performance evaluation based on Peak Signal-to-Noise Ratio (PSNR) and Normalized Correlation (NC) demonstrates significant improvements in watermark quality and resilience against attacks. Identifying the gap to improve NC values, we modified the existing algorithm only in extraction process and because of new algorithm, NC values improved for many attacks including Rotation Attack.The measured PSNR and NC values are tabulated for all the 3 planes(RED,GREEN and BLUE) for 6 selected attacks and even without attack.