Robust image watermarking using two dimensional Walsh coding

2012 ◽

Vol 616-618 ◽

pp. 2214-2218

Author(s):

Ming Hui Deng

Keyword(s):

Image Watermarking ◽

Geometric Distortion ◽

Energy Concentration ◽

Frequency Change ◽

Identification Algorithm ◽

Two Dimensional ◽

Time Frequency ◽

Chirp Signals ◽

Wigner Transformation ◽

Robust Image

In this paper, a robust image watermarking method with one-dimensional improved S transformation is proposed which is robust against geometric distortion. This watermarking is detected by a linear frequency change. The chirp signals are used as watermarks and this type of signals is resistant to all stationary filtering methods and exhibits geometrical symmetry. In the two-dimensional Radon-Wigner transformation domain, the chirp signals used as watermarks change only its position in space/spatial-frequency distribution, after applying linear geometrical attack. But the two-dimensional Radon-Wigner transformation needs too much difficult computing. We propose a modified Gaussian window which scales with the frequency in an efficient manner to provide improved energy concentration of the S-transform. The proposed scheme can resolve the time-frequency localization in a better way than the standard S transformation. The watermark is embedded in the 1D improved S transformation domains. The watermark thus generated is invisible and performs well in test and is robust to geometrical attacks. Compared with other watermarking algorithms, this algorithm is more robust, especially against geometric distortion, while having excellent frequency properties.

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Robust Watermarking Algorithm Based on Hilbert-Huang Theory

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.255-260.2291 ◽

2011 ◽

Vol 255-260 ◽

pp. 2291-2295

Author(s):

Ming Hui Deng ◽

Qing Shuang Zeng ◽

Xiu Li Zhou

Keyword(s):

Image Watermarking ◽

Time Windows ◽

Geometric Distortion ◽

Frequency Change ◽

Two Dimensional ◽

Hilbert Huang Transform ◽

Chirp Signals ◽

Wigner Transformation ◽

Robust Image ◽

Frequency Properties

In this paper, we introduce a robust image watermarking method based on Hilbert-Huang Transform (HHT) against geometric distortion. This watermarking is detected by a linear frequency change. The HHT transformation is used to detect the watermark. The chirp signals are used as watermarks and this type of signals is resistant to all stationary filtering methods and exhibits geometrical symmetry. In the two-dimensional Radon-Wigner transformation domain, the chirp signals used as watermarks change only its position in space/spatial-frequency distribution, after applying linear geometrical attack, such as scale rotation and cropping. But the two-dimensional Radon-Wigner transformation needs too much difficult computing. So the image is put into a series of 1D signal by choosing scalable local time windows. The watermark embedded in the HHT transformation domain. The watermark thus generated is invisible and performs well in StirMark test and is robust to geometrical attacks. Compared with other watermarking algorithms, this algorithm is more robust, especially against geometric distortion, while having excellent frequency properties.

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