Spread-spectrum techniques for wireless communication

Flikkema, Paul G.

doi:10.1109/79.587050

Cited by 113 publications

(40 citation statements)

References 25 publications

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“…We remark that many current watermarking methods are based on spread-spectrum communications [15], [16]. The seminal work on digital image fingerprinting by Cox et al in [3] popularized the use of direct-sequence spread-spectrum for watermarking.…”

Section: A Watermark Embeddingmentioning

confidence: 99%

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Power-spectrum condition for energy-efficient watermarking

Girod

2002

IEEE Trans. Multimedia

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Abstract-This paper presents a model for watermarking and some attacks on watermarks. Given the watermarked signal, the so-called Wiener attack performs minimum mean-squared error (MMSE) estimation of the watermark and subtracts the weighted MMSE estimate from the watermarked signal. Under the assumption of a fixed correlation detector, the attack is shown to minimize the expected correlation statistic for the same attack distortion among linear, shift-invariant filtering attacks. It also leads to the idea of energy-efficient watermarking-watermarking that resists MMSE estimation as much as possible-and provides a meaningful way to evaluate robustness. The paper shows that energy-efficient watermarks must satisfy a power-spectrum condition (PSC), which states that the watermark's power spectrum should be directly proportional to the original signal's. PSC-compliant watermarks are proven to be most robust. Experiments with signal models and natural images demonstrate that watermarks that do not closely fulfill the PSC are vulnerable to the Wiener attack, while PSC-compliant watermarks are highly resistant to it. These theoretical and experimental results justify prior heuristic arguments that, for maximum robustness, a watermark should be closely matched to the spectral content of the original signal. The results also discourage the use of watermarks that do not approximately satisfy the PSC.Index Terms-Digital watermarking, robustness, spread spectrum, watermark attacks.

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Section: A Watermark Embeddingmentioning

confidence: 99%

“…We denote this special value of by , (16) This choice of drives to zero with the minimum corresponding distortion . Since usually , the probability that the detector mistakenly decides that is not present in is at least 0.5.…”

Section: ) Anticorrelation Attackmentioning

confidence: 99%

Power-spectrum condition for energy-efficient watermarking

Girod

2002

IEEE Trans. Multimedia

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“…In all cases, the ToA estimate is converted to a range estimate based on the speed of sound in air. Two kinds of FH-SS modulation exist, Slow and Fast FH [13]. In Fast FH-SS each data bit hops several times, while Slow FH-SS uses several bits per frequency hop.…”

Section: A Fh-ss Modulationmentioning

confidence: 99%

Ultrasonic Orientation-Location Algorithm Based on ToA and AoA Measurements

Gonzalez

Bleakley

2008

2008 IEEE 10th International Symposium on Spread Spectrum Techniques and Applications

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“…For each DCT block, the middle frequency components F M are added to the pseudo number sequence W, multiplied by a gain factor k. Coefficients in the low and high frequencies are copied over to the transformed image unaffected. Each block is then inverse-transformed to give us our final watermarked image I W [9].…”

Section: Dct Domain Watermarkingmentioning

confidence: 99%

An Improved and Robust DCT Based Digital Image Watermarking Scheme

Tewari¹,

Saxena²

2010

IJCA

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The need for displaying one"s own multimedia content on the internet is increasing day by day. With the exponential growth of internet and high speed networks operating through out the world it"s a challenging task to protect copyright of an individual"s creation. Digital watermarking provides a viable solution to protect copyright and authenticate the ownership of an intellectual property. In this paper we propose a new DCT based additive watermarking scheme which provides higher resistance to image processing attacks mainly JPEG compression. In our approach the watermark is embedded in the mid frequency band of the DCT blocks only in the sub band which is carrying low frequency components and the high frequency sub band components remain untouched. General Terms KeywordsAveraged DCT blocks, pixel intensity, INTRODUCTIONThe recent development of network multimedia systems & explosion of fast communication network has discouraged & damped the multimedia content providers i.e. authors, publishers to grant the distribution of their document on the network environment. The intellectual property authentication has become an issue of concern[1] While a considerable efforts and a lot of economic resources are used for the creation of intellectual property particularly in industrial societies, the cost of reproducing such intellectual creations typically constitute only a small portion of the creation. However a creator always desires some rewards or incentives for his creation which he is not able to get due to low cost copying. More and more researchers are attracted to the area of image watermarking because of the property of the image as it has a lot of redundant information contained in it which can be exploited to be used for watermark insertion. Cox et. al uses DCT domain for watermark embed for the first time .As JPEG standard also uses DCT for image compression it is always a good idea to explore image watermarking and robustness of watermark in DCT domain. The paper is divided into following sections .Section 2 gives the description of the common DCT based watermark insertion technique which works as the base of our proposed algorithm section 3 gives the description of the proposed scheme Section 4 describes the results and the discussion on the results followed by the conclusion in Section 5. DCT DOMAIN WATERMARKINGDiscrete-Cosine-Transform or DCT is a popular transform domain watermarking technique. The DCT allows an image to be broken up into different frequency bands namely the high ,middle and low frequency bands thus making it easier to to choose the band in which the watermark is to be inserted. The literature survey reveals that mostly the middle frequency bands are chosen because embedding the watermark in a middle frequency band do not scatter the watermark information to most visual important parts of the image i.e. the low frequencies and also it do not overexpose them to removal through compression and noise attacks where high frequency components are targeted.[17]. Numerous watermarking...

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Spread-spectrum techniques for wireless communication

Cited by 113 publications

References 25 publications

Power-spectrum condition for energy-efficient watermarking

Power-spectrum condition for energy-efficient watermarking

Ultrasonic Orientation-Location Algorithm Based on ToA and AoA Measurements

An Improved and Robust DCT Based Digital Image Watermarking Scheme

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