A blind watermark algorithm for medical images using ROI and contourlet
LI Wen-n · Harbin Gongcheng Daxue Xuebao/Journal of Harbin Engineering University · 2013
A blind watermarking algorithm which combined region of interest(ROI) with Contourlet transform has been proposed in view of the existing watermark algorithms which can not realize simultaneously the information hiding and authentication for digital imaging and communications in medicine(DICOM) images.The watermark w1 consisted of patient's private information and the subblocks means of ROI was embedded into background(BG) of DICOM image using a reversible technique based on modified difference expansion.After that authentication watermark w2 was embedded into the high-order greater energy directional subbands of the first watermarked image's contourlet domain using the method of comparing the contourlet coefficient and its 8-neighborhood mean.The scheme is a blind watermarking algorithm,and is able to locate and recover tampered regions with a very good visual quality to ensure image authenticity and integrity for diagnosis.Theoretical analysis and numerical experiments show that the scheme has a high capacity of data hiding as well as anti-attack ability.