A New Blind Image Watermarking of Handwritten Signatures using Low-Frequency Band DCT Coefficients

Author(s):  
Ahmed N. Al-Gindy ◽  
Hussain Al Ahmad ◽  
Ayman Tawfik ◽  
Rami A. Qahwaji
2013 ◽  
Vol 339 ◽  
pp. 275-280
Author(s):  
Li Chen ◽  
Rong Hua Peng

A new algorithm is proposed for digital watermarking by applying complex-valued linear-phase filter banks to low frequency-band coefficients of images in the DCT domain. The watermark is conveyed in the phase spectrum of the subband coefficients. The robustness of the algorithm is examined in JPEG encoding with different qualities and compared with the DFT-based approach. Because only low frequency-band DCT coefficients are applied to complex-valued filter banks, the computational load introduced by the complex-valued filter banks is kept low. The watermark decoding is only accessible to users with the key information, i.e., impulse responses of the complex-valued linear-phase filter banks that designed with time-frequency spread property.


Watermarking is the way toward concealing advanced mystery data in a picture. The best in class watermark implanting plans with the assistance of spread range and quantization, experiences Host Signal Interference (HSI) and scaling assaults, separately. They fixed the inserting parameter, which is hard to consider both power and subtlety for all pictures. This paper takes care of the issues by proposing a visually impaired watermarking strategy, Spread Spectrum Scheme with Adaptive Embedding Strength (SSAES). Their adaptiveness originates from the proposed Adaptive Embedding Strategy (AEP), which expands the installing quality or quantization limit by ensuring the Peak Signal-to-Noise Ratio (PSNR) of the host picture.SSAES includes free of HSI by calculating in the earlier information about HSI. We present a thought called mistake limit to hypothetically dissect the exhibition of our proposed techniques in detail. Further, to improve the security of the watermarked picture, the DCT coefficients are exposed to stage based encryption. This will improve the security of a watermarked picture. The test results reliably exhibit that SSAES outflank the best in class strategies regarding intangibility, power, computational expense, and flexibility. Along these lines the proposed course of action of picture watermarking routs the drawbacks of host signal impedance security ambushes and scaling attack.


2018 ◽  
Vol 10 (1) ◽  
pp. 54-66
Author(s):  
Zhuoqian Liang ◽  
Bingwen Feng ◽  
Xuba Xu ◽  
Xiaotian Wu ◽  
Tao Yang

In this article, a blind image watermarking scheme, which is a robust against common image processing and geometric attacks is proposed by adopting the concept of histogram-based embedding. The average filter is employed to low-pass pre-filter the host image. The watermark bits are embedded into the histogram of the low-frequency component and the template bits are embedded in the high-frequency residual. The embedding is performed by adjusting the value of two consecutive histogram bins. Furthermore, a post-quantization is employed after the embedding round to improve robustness. All pixel modifications incurred are based on the human visual system (HVS) characteristics. As a result, a good tradeoff between robustness and imperceptibility is achieved. Experimental results reported the satisfactory performance of the proposed scheme with respect to both common image processing and geometric attacks.


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