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Search Results: 1 - 10 of 8949 matches for " oblivious watermark detection "
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Embedding Color Watermarks in Color Images
Tung-Lin Wu,Chun-Hsien Chou
EURASIP Journal on Advances in Signal Processing , 2003, DOI: 10.1155/s1687617203211227
Abstract: Robust watermarking with oblivious detection is essential to practical copyright protection of digital images. Effective exploitation of the characteristics of human visual perception to color stimuli helps to develop the watermarking scheme that fills the requirement. In this paper, an oblivious watermarking scheme that embeds color watermarks in color images is proposed. Through color gamut analysis and quantizer design, color watermarks are embedded by modifying quantization indices of color pixels without resulting in perceivable distortion. Only a small amount of information including the specification of color gamut, quantizer stepsize, and color tables is required to extract the watermark. Experimental results show that the proposed watermarking scheme is computationally simple and quite robust in face of various attacks such as cropping, low-pass filtering, white-noise addition, scaling, and JPEG compression with high compression ratios.
A Simple Image Tamper Detection and Recovery Based on Fragile Watermark with One Parity Section and Two Restoration Sections  [PDF]
Chao-Ming Wu, Yan-Shuo Shih
Optics and Photonics Journal (OPJ) , 2013, DOI: 10.4236/opj.2013.32B026

A fragile self-recovery watermarking scheme with simple and effective tamper detection capability is proposed in this paper. In conventional fragile watermark for tamper detection and recovery, the parity section of the watermark is used for tamper detection and the restoration section of the watermark is used for image recovery, separately. In addition, to provide second chance for block recovery in case one copy is destroyed, Lee and Lin proposed dual watermarking scheme in which two copies of restoration watermark are embedded. In the proposed new scheme, fragile watermark with one parity section and two restoration sections are embedded, too. In addition to the second chance for image restoration, the two restoration sections as well as the parity section are all used for tamper detection. Experimental results show that the tamper detection capability is superior to other techniques.

Robust Non-Oblivious Dwt-Adaptive Invisible Digital Watermarking
Sri K.Naga Prakash,Ms.G.Sindhuri,Mr.K.Akshay,Mr.G.Apuroop
International Journal on Computer Science and Engineering , 2011,
Abstract: The main idea of this paper is embedding invisible watermark into an image. The advantage of this method over previous works is that it is easy to embed and robust to attacks. Non-oblivious detection technique is used. This is implemented using matlab and is verified for the robustness and results with previous are compared. Here we introduced a factor k as scaling factor for the watermark.To make the embedding more strong divide the image into different sublevels and each sublevel is again divided into sub bands and watermark is embedded into each sub band except the low frequency band . TO achieve this we adapted the transform domain method using the DWT .To Hvs minute changes in high frequencies are imperceptible ,hence based on this we perform invisible watermarking. .We use dwt transform domain as it is better to embed the watermark in transform domain, selecting only perceptually significant coefficients, because those are the most likely to survive compression. We use a non-oblivious technique for detection of the watermark and extract it from the cover image
Robust Multibit Decoding and Detection of Multiplicative Watermarks for Fingerprint Images
Khalil Zebbiche,Foued Khelifi,Ahmed Bouridane
Journal of Multimedia , 2010, DOI: 10.4304/jmm.5.2.167-180
Abstract: In this paper, multibit watermark decoding and detection structures of fingerprint images are proposed. The watermark is hidden within the high frequencies coeffi- cients of the discrete wavelet transform (DWT) which are statistically modeled by generalized Gaussian distribution. The structure of the decoder and the detector are based on the maximum-likelihood (ML) method. For flexibility purposes, the original image is not necessary during the decoding and the detection processes. Analytical expressions for performance measures such as the probability of error in watermark decoding and probabilities of false alarm and detection in watermark detection are derived and contrasted with experimental results. The results obtained are very attractive when considering a number of commonly used attacks and the proposed detector and decoder have been shown to outperform similar detectors/decoders existing in the literature. They also show that the overall performances of both decoder and detector are dependent on the fingerprint image characteristics, namely, on the size of the ridges area relative to the size of the fingerprint image.
Robust Image Watermarking Scheme Based on Wavelet Technique
Aree Ali Mohammed, Haval Mohammed Sidqi
International Journal of Computer Science and Security , 2011,
Abstract: In this paper, an image watermarking scheme based on multi bands wavelet transformationmethod is proposed. At first, the proposed scheme is tested on the spatial domain (for both a nonand semi blind techniques) in order to compare its results with a frequency domain. In thefrequency domain, an adaptive scheme is designed and implemented based on the bandsselection criteria to embed the watermark. These criteria depend on the number of waveletpasses. In this work three methods are developed to embed the watermark (one band(LL|HH|HL|LH), two bands (LL&HH | LL&HL | LL&LH | HL&LH | HL&HH | LH&HH) and threebands (LL&HL&LH | LL&HH&HL | LL&HH&LH | LH&HH&HL) selection. The analysis resultsindicate that the performance of the proposed watermarking scheme for the non-blind scheme ismuch better than semi-blind scheme in terms of similarity of extracted watermark, while thesecurity of semi-blind is relatively high. The results show that in frequency domain when thewatermark is added to the two bands (HL and LH) for No. of pass =3 led to good correlationbetween original and extracted watermark around (similarity = 99%), and leads to reconstructedimages of good objective quality (PSNR=24 dB) after JPEG compression attack (QF=25). Thedisadvantage of the scheme is the involvement of a large number of wavelet bands in theembedding process.
Digital Watermarking System based on Cascading Haar Wavelet Transform and Discrete Wavelet Transform
Nidal F. Shilbayeh,Adham Alshamary
Journal of Applied Sciences , 2010,
Abstract: The aim of this study was to solve problems of modification, forgery, illegal manipulation and distribution of digital image, especially with the rapid growth of transmission techniques. Although, there are many ways to protect the images, the proposed system suggested a new technique to protect the image for the purposes of ownership, copyright and intellectual property. In this study, we present a new robust and secure hybrid watermarking technique based on Haar Wavelet Transformation (HWT) and Discrete Wavelet Transformation (DWT). The proposed method is constructed by cascading two different but complementary techniques: HWT and DWT wavelet transformations to provide a robust resistance to the protected image against different signal processing attacks. Adding a private key to the watermarking will increase the privacy and security, but by embedding watermark in that private key more protection in wavelet transform will result, leading to more resistant against attacks. The new technique has been proposed to solve the problem of illegal manipulation and distribution of digital image, i.e., HWT and DWT system. Performance evaluation of the proposed method showed improved results in terms of imperceptibility, robustness and security in comparison with others systems.
Determining Watermark Embedding Strength using Complex Valued Neural Network
R.F. Olanrewaju,O.O. Khalifa,Aisha- Abdulla,A.A. Aburas
Journal of Applied Sciences , 2011,
Abstract: The requirements needed for an effective and proficient watermarking system is application dependent. However, robustness and image quality (imperceptibility) are fundamental requirements for applications that deal with image watermarking. The major factor that affects the robustness and imperceptibility is the watermark embedding strength. In this study, a CVNN based adaptive technique of estimating watermark embedding strength for a digital image is presented. Experimental results indicated that CVNN based method can estimate the watermarking strength, gives a better correlation and an improved imperceptibility of the watermarked image. It also demonstrates that the detection is enhanced. The use of this new method in watermarking achieved content authentication and helps overcome the problem of visual artifacts and distortions created during watermark embedding.
The Influence of Image Enhancement Filters on a Watermark Detection Rate
Ante Polji?ak,Lidija Mandi?,Maja Strgar Kure?i?
Acta Graphica : Journal for Printing Science and Graphic Communications , 2012,
Abstract: In this paper is evaluated the effect of image enhancement filters on the watermarkdetection rate. State-of-the-art watermarking methods are still very sensitiveto complex degradation attack such as print-scan process, so the detection rate of awatermark method decreases considerably after such an attack on a watermarkedimage. Therefore, to improve the detection rate, the degradation of the image isreduced by using image enhancement filters. A dataset of 1000 images was watermarked,printed and scanned for the experiment. Scanned images were enhancedby means of an unsharp filter and blind deconvolution filter. The watermark detectionrate was measured and compared before and after the enhancement. Theresults show that the enhancement filtering improves the watermark detection rateby almost 10 %.
Research of image based watermarking attack algorithms

WANG Ying,ZHENG Xue feng,LIU Hai yan,

计算机应用研究 , 2008,
Abstract: Digital watermarking techniques are proposed to meet the urgent requirement.Robustness against attack is the basic demand of digital watermarking.Many algorithms claim to be robust against various transformations,and in order to verify the robustness,lots of attack techniques have been developed.This paper summaried digital image watermark attack algorithms comprehensively and introduced some unresolved problems.Finally,it proposed promising directions.
Implementations of HVS Models in Digital Image Watermarking
P. Foris,D. Levicky
Radioengineering , 2007,
Abstract: In the paper two possible implementations of Human Visual System (HVS) models in digital watermarking of still images are presented. The first method performs watermark embedding in transform domain of Discrete Cosine Transform (DCT) and the second method is based on Discrete Wavelet Transform (DWT). Both methods use HVS models to select perceptually significant transform coefficients and at the same time to determine the bounds of modification of selected coefficients in watermark embedding process. The HVS models in DCT and DWT domains consist of three parts which exploit various properties of human eye. The first part is the HVS model in DCT (DWT) domain based on three basic properties of human vision: frequency sensitivity, luminance sensitivity and masking effects. The second part is the HVS model based on Region of Interest (ROI). It is composed of contrast thresholds as a function of spatial frequency and eye's eccentricity. The third part is the HVS model based on noise visibility in an image and is described by so called Noise Visibility Function (NVF). Watermark detection is performed without use of original image and watermarks have a form of real number sequences with normal distribution zero mean and unit variance. The robustness of presented perceptual watermarking methods against various types of attacks is also briefly discussed.
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