Image content authentication and tamper localization based on semi fragile watermarking by using the Curvelet transform

The large variety of signal processing tools available today permits to anyone to easily modify digital multimedia objects like images without leaving any perceptible trace of the modifications. Therefore the digital image authentication becomes a very important issue. In this paper we propose a semi-fragile image watermarking scheme for image authentication and tamper localization. The watermark bits are embedded into coarse level Curvelet coefficients. The extracted watermark is used to determine whether the watermarked image has been modified or not and also has the ability to localize the tampered regions. The experimental results show that our proposed method is also robust against attacks such as JPEG compression and noise contamination and the imperceptibility of watermarked image is acceptable.