Blind Watermarking in Contourlet Domain with Improved Detection

Abstract

This paper presents a novel method of blind image watermarking in contourlet domain. We have used spread spectrum technique for additive watermark embedding. A correlation detector is used to detect the embedded pseudorandom sequence. The binary logo thus retrieved proves authenticity of the image. The similarity of the retrieved binary logo with the original embedded logo is veriJied using correlation technique. Post processing of the retrieved logo gives better visual effects, further aiding threshold selection for detection. We have verijied the robustness of the proposed method against dzrerent attacks including StirMark attack. The proposed method is compared with a wavelet based blind technique and the results prove that contourlet based technique gives better robustness, under similar embedding conditions.

Contourlet-Based Image Watermarking Using Optimum Detector in a Noisy Environment

“…For the noise free environment, (20) and (21) can be simplified as (22) where where and are the inverse functions of and , respectively. Considering (3), we need to have the standard deviation and the shape parameter of the GGD function for the supposed directional subband in each block.…”

A New Visually Imperceptible and Robust Image Watermarking Scheme in Contourlet Domain

“…Performance of the proposed algorithm has been tested under several attacks including JPEG lossy compression, addition of noise, image degradation like filtering, image rescaling and dithering. The results are compared with a method in contourlet domain [6], entitled "Contourlet1"in this paper and a wavelet-based method propose in [7], entitled "wavelet" in this paper. In [6], 75% of coefficients of band Y are watermarked with a pseudorandom sequence.…”

“…The results are compared with a method in contourlet domain [6], entitled "Contourlet1"in this paper and a wavelet-based method propose in [7], entitled "wavelet" in this paper. In [6], 75% of coefficients of band Y are watermarked with a pseudorandom sequence. Our simulated version of [7] differs from the original version in the fact that, we have used 4 LL and 4 HH (due to their highest and lowest variances among all other sub bands, respectively) for watermarking embedding, instead of LL and HH used in [7].…”

“…The scheme is blind and decoding process requires only the pseudo noise (PN) matrices, unlike some other SS watermarking scheme in Contourlet domain [5], where data recovery process require the whole cover image. We have compared our method with another contourlet based watermarking method [6] and also a wavelet based method [7]. The normalized correlation coefficients after different attacks were calculated for all the methods.…”

Contourlet Transform Based Watermarking for Colour Images

“…Discrete Contourlet Transform (CT) is capable of capturing the directional information with multiresolution representation [6,11]. It makes use of Laplacian Pyramid for multiresolution representation of the image [9,10] followed by a directional decomposition on every band pass image using directional filters [8,10].…”