A Robust Fractal Color Image Watermarking Algorithm

Abstract

One of the main objectives of watermarking is to achieve a better tradeoff between robustness and high visual quality of a host image. In recent years, there has been a significant development in gray-level image watermarking using fractal-based method. This paper presents a human visual system (HVS) based fractal watermarking method for color images. In the proposed method, a color pixel is considered as a 3-D vector inRGBspace. And a general form of 3 × 3 matrix is utilized as the scaling operator. Meanwhile, the luminance offset vector is substituted by the range block mean vector. Then an orthogonalization fractal color coding method is achieved to obtain very high image quality. We also show that the orthogonalization fractal color decoding is a mean vector-invariant iteration. So, the range block mean vector is a good place for hiding watermark. Furthermore, for consistency with the characteristics of the HVS, we carry out the embedding process in theCIE La*b*space and incorporate a just noticeable difference (JND) profile to ensure the watermark invisibility. Experimental results show that the proposed method has good robustness against various typical attacks, at the same time, with an imperceptible change in image quality.

Digital Watermarking Using Fractal Coding

“…The robustness of the algorithm is shown in PSNR calculations. The results show that the method is comparable to the methods discussed by Jian Lu et al [1] and SoheilaKiani et al [2].…”

“…the most similar block which had found during fract equal. Table 2 gives the comparative study of the pr methods discussed by Jian Lu et al [1] The watermarked image's robustness was evaluated by attacking the image through various image manipulation procedures like cropping, adding noise and compression etc. Then the watermark was extracted from these manipulated images and compared with the original watermark image.…”

“…Range blocks are modified and watermark bit is inserted based on its value. A robust fractal color image watermarking algorithm [1] was proposed by Jian Lu, Yuru Zou, Chaoying Yang, and Lijing Wangis to achieve a better tradeoff between robustness and high visual quality of a host image. Rao and Prasad have presented a method based on ridgelets and discrete wavelet transform techniques [14].…”

A new key agreement protocol based on Chebyshev chaotic maps

“…Chaotic maps have complex nonlinear dynamical behavior, they have been widely used in the filed of image encryption and key agreement protocols because of some characteristics such as sensitivity to initial conditions, unpredictability and the excellent pseudo‐random sequences . Compared with the general one‐dimensional chaotic maps, the Chebyshev map is characterized by chaotic features such as larger parameter space, uniform data distribution, the greater the Lyapunov exponent, and semi‐group features.…”

Fractal Image Coding Based on a Fitting Surface

“…Then, Jacquin [2] introduced the first practical fractal coding scheme. After many years of development, it has been successfully used in many image processing applications such as image compression [3], image denoising [4,5], image retrieval [6,7], image magnification [8,9], and image watermarking [10][11][12].…”