Multifaceted Watermarking of Medical Images Using SWT and SVD

Abstract

Radiological image transmission over network is extensively increased. A slight alteration  of the image may lead to faulty diagnosis. To better address this problem, a high capacity watermarking technique with tamper localization capability for various medical  image modalities is proposed. Two equal sized watermarks as that of cover image has been embedded.  Stationary Wavelet Transform (SWT) followed by Singular Value Decomposition (SVD) is employed to embed patient data as one of the watermarks for ownership identification. Tamper detection and localization is accomplished by embedding a fragile watermark using Least Significant Bit (LSB) replacement method. Experimental results prove that this approach attains excellent robustness and significantly better imperceptibility while precisely locating the invisible tampers in the image. This approach is evaluated against state of the art techniques and verified to be outperformed. This scheme not only focuses on robustness and imperceptibility but also maximizes embedding capacity in addition to tamper localization  that constitutes this method a multifaceted watermarking scheme.

Keywords  Medical Image Watermarking; LSB Replacement; Stationary Wavelet Transform; Singular Value Decomposition.