Watermark Signal Research Articles

Adjustable audio watermarking algorithm based on DWPT and psychoacoustic modeling

This paper presents a novel adjustable audio watermarking method with high auditory quality by exploiting the discrete wavelet packet transform (DWPT), psychoacoustic modeling and distortion compensated-dither modulation (DC-DM) quantization. While the DWPT is used to divide the audio frames into several frequency sub-bands, the psychoacoustic model is intergraded to determine the appropriate sub-bands for watermarking and to control the number of embedded bits in each one. Then, the DC-DM technique is used to embed the watermark bits into the appropriate DWPT coefficients. The synchronization code technique is adopted in the proposed method to withstand desynchronization attacks. In order to achieve an adjustable watermarking scheme, two regulator parameters are provided to manage the capacity-robustness trade-off. The performance of the watermarking scheme is evaluated by examining different host audio signals under various watermarking attacks. The results show excellent imperceptibility of watermarked signals with an average ODG of − 0.3. In addition, the proposed scheme provides strong robustness against the attacks with low capacity. However, high capacity (about 2500 bps) can be achieved while maintaining a reasonable robustness. A comparison with some state-of-the-art audio watermarking schemes reveals that the proposed method provides competitive results.

A subband excitation substitute based scheme for narrowband speech watermarking

We propose a new narrowband speech watermarking scheme by replacing part of the speech with a scaled and spectrally shaped hidden signal. Theoretically, it is proved that if a small amount of host speech is modified, then not only an ideal channel model for hidden communication can be established, but also high imperceptibility and good intelligibility can be achieved. Furthermore, a practical system implementation is proposed. At the embedder, the power normalization criterion is first imposed on a passband watermark signal by forcing its power level to be the same as the original passband excitation of the cover speech, and a synthesis filter is then used to spectrally shape the scaled watermark signal. At the extractor, a bandpass filter is first used to get rid of the out-of-band signal, and an analysis filter is then employed to compensate for the distortion introduced by the synthesis filter. Experimental results show that the data rate is as high as 400 bits/s with better bandwidth efficiency, and good imperceptibility is achieved. Moreover, this method is robust against various attacks existing in real applications.

Audio-Speech Watermarking Using a Channel Equalizer

Currently, the use of telephone systems is highly popular in speech telecommunication and also they have a wide presence in transmission of digital signals. In recent years, audio-speech watermarking as a modern technique makes use of the telephone channel to transmit the watermark data, but addressing the watermark’s vulnerability to noise in the telephone channel is a difficult problem in digital audio-speech watermarking. This paper presents a robust audio-speech watermarking scheme that operates against channel noise according to audio-speech specifications, the channel coding and channel equalizer technique. The proposed scheme is based on the spread spectrum technique and a psychoacoustic model with use of the channel equalizer to remove or minimize the effects of channel noise over the watermark signal. The simulation results for imperceptibility of the watermark, voice quality, and robustness against channel noise are presented in this study. The results indicate that the proposed scheme is highly satisfactory for the cases mentioned above.

SIFT based video watermarking resistant to temporal scaling

In this paper, a blind video watermarking scheme is proposed which can resist temporal scaling such as frame dropping and frame rate adaptation due to scalable compression by exploiting the scale invariance property of the scale invariant feature transform (SIFT). A video scene can also be viewed from side plane where height is the number of rows in a video frame, width is the number of frames in the scene and depth is the number of columns in the frame. In this work, intensity values of selected embedding locations changed such that strong SIFT feature can be generated. SIFT features are extracted from side plane of the video. These newly generated SIFT features are used for watermark signal and are stored in the database for the authentication. A comprehensive set of experiments has been done to demonstrate the efficacy of the proposed scheme over the existing literature against temporal attacks.

A new approach for digital image watermarking to predict optimal blocks using artificial neural networks

In this paper, we propose a novel nonblind digital image watermarking based on discrete wavelet transform and singular value decomposition. This robust scheme takes advantage of artificial neural networks for selecting suitable image blocks in which the watermark signal can be embedded. Local characteristics of the blocks such as luminance and texture sensitivity are the main criteria that the selections are based on. Generally, selection is based on a prediction of the results with the objective of transparency and watermark resilience. In other words, before embedding the water mark signal, it is estimated which blocks would be the best for embedding the signals to achieve the desired robustness and quality. Simulation results confirm the superiority of the proposed scheme in terms of the transparency of the images as well as robustness under various kinds of attacks.

Channel Capacity Analysis of Spread Spectrum Watermarking in Radio Frequency Signals

The carrier of the digital watermark expands from audio signals to radio frequency (RF) signals. Unlike audio signals, RF signals, such as the watermark transmission carrier, must be correctly demodulated with the watermark signals so that the distortion of the digital carrier embedded with the watermark is associated with the change in bit error rate. Based on the spread spectrum watermarking scheme, the distortion of the digital carrier signal is redefined, and the channel capacity expression of the watermarking scheme is derived. In addition, the optimal parameters to achieve the maximal channel capacity are discussed, and the constraint relation between the channel capacity and the allowable distortion is investigated.

Semifragile Speech Watermarking Based on Least Significant Bit Replacement of Line Spectral Frequencies

There are various techniques for speech watermarking based on modifying the linear prediction coefficients (LPCs); however, the estimated and modified LPCs vary from each other even without attacks. Because line spectral frequency (LSF) has less sensitivity to watermarking than LPC, watermark bits are embedded into the maximum number of LSFs by applying the least significant bit replacement (LSBR) method. To reduce the differences between estimated and modified LPCs, a checking loop is added to minimize the watermark extraction error. Experimental results show that the proposed semifragile speech watermarking method can provide high imperceptibility and that any manipulation of the watermark signal destroys the watermark bits since manipulation changes it to a random stream of bits.

Audio Activity Detection for Watermarking Based on Wavelet Denoising

Objectives: The watermark embedding in Non-Activity Region (NAR) of the underlying audio signal results for the degradation of audio quality. This research focused on the development of audio activity detection method for the audio watermarking procedure to prevent from watermark embedding in the NAR. Methods/Statistical Analysis: We propose the audio activity detection method based on the wavelet denoising algorithm to classify the NAR in audio signal. We experiment and apply three- type wavelet denoising algorithms, subsequently the wavelet denoising algorithms showed the same performance. We analyze the audio quality by the Signal to Noise Ratio (SNR) for two cases that the embedding and non-embedding of watermark in the NAR. Findings: We surveyed the effects on the watermarking embedding in the NAR. Decreasing a payload on watermarking, the watermark embedding in the NAR increases the audio quality in SNR and audio test by MUSHRA (Multi Stimulus Test with Hidden Reference and Anchor). In extraction process the extraction rate of embedded watermark is slightly increasing when our method is applied. In comparisons of the other research results such as DFT (Discrete Fourier Transform) based method and MFCC (Mel Frequency Cepstral Coefficients) based method, our method has the better accuracy in AAD. And also our method is in low complexity for the analysis of computational complexity by the effective computational structure of filter bank for implementation of wavelet filter. In additional research results, we find out that the audio signal in the NAR has a random- like pattern by the analysis of power spectrum of it.In statistical experiment a signal in NAR analyzed by statistical parameters such as mean and variance. As a result, our method is effective for computational complexity and produces good audio quality for the watermark embedding procedure. Improvements/Applications: Our method for audio activity detection is very effective computational complexity and produces high audio quality for watermark embedding procedure. It is applicable for the audio watermarking system for high- quality watermarked audio signal.

A practical design of digital watermarking for video streaming services

A practical design of digital watermarking for video streaming services is proposed in this research. The information of a legitimate recipient is represented as a watermark, which is embedded in the video stream to serve as a cue to trace the recipient in case a clone of the video is illegally distributed. The watermark signals are designed to embed in some areas of video frames to benefit the video stream server, as the result of only partial actions required, including decoding, processing and re-encoding. The invariance of feature points and the self-similarity of hidden signals are further exploited to enable watermark detection without involving the original video. The watermark can decently survive transcoding processes and geometrical modifications of frames. The experimental results demonstrate the advantages of the proposed scheme in terms of watermark visibility, capacity and detection methodology.

Digital Watermarking Processing Technique Based on Overcomplete Dictionary

A novel sparse domain-based information hiding framework is proposed in this paper to attach the watermarking signal to the most significant sparse components of the host signal over the pre-defined overcomplete dictionary. The adaptive sparse domain can be utilized to embed watermarking logo with better security and robustness. This can be realized owing to the fact that, not only the sparse domain can be customized from the given samples, but also the sparse transform coefficients of the original watermarking signal can be embedded, which provides inherent privacy. This paper provides two kinds of methods that embed watermark directly and embed the sparse representation coefficients of watermarking logo, and analyzes the condition of uniqueness of the sparse solution. Experimental results demonstrate the superiority of the proposed sparse domain digital watermarking technique over the traditional frequency domain or spatial domain schemes.

A speech content authentication algorithm based on a novel watermarking method

Some audio watermark schemes robust against desynchronization attacks are based on synchronization code embedded by quantifying signal energy, which have some shortcomings. Such as, (1) they do not verify the authenticity of watermarked signal detected. (2) They are vulnerable to substitution attack. To address the shortcomings and considering the background, a speech content authentication algorithm is proposed in this paper. Firstly, the original speech signal is framed, and each frame is cut into some segments. Secondly, samples of the segments are scrambled, and self-correlation of the scrambled signal is calculated. Lastly, watermark bit generated by frame number is embedded by quantifying the self-correlation. If watermarked signal is attacked, the attacked frames can be detected according to the frame number extracted. Theoretical analysis and experiments demonstrate that the scheme is robust against desynchronization attacks, improves the security, and has a good performance in ability of tampering location.

AUDIO WATERMARKING IN DIGITAL IMAGE USING WAVELET TRANSFORM

Digital watermarking is the act of hiding a message related to a digital signal (i.e. an image, song, video) within the signal itself. It is a concept closely related to steganography, in that they both hide a message inside a digital signal The rapid development in digital technologies has necessitated the owners to pay great attention in protecting their digital contents. Watermarking is used for content authentication and ownership protection. Biometric data provide unique means for individual identification. Biometric watermarking refers to the incorporation of biometric data in watermarking technology. By embedding biometrics in the host, it formulates a reliable individual identification as biometrics possesses exclusive characteristics that can be hardly counterfeited. In this paper we proposed a method of embedding owner's speech signal. Speech being a biometric data, the watermark signal in this method is expected to be more meaningful and has closer correlation with copyright holder. KeywordsBiometric Speech, Watermarking, Common & Geometric attacks, Copyright protection, Authentication, Wavelet transform.

Embedding QR Code in the Wavelet Domain of Image for Metadata Hiding

Background/Objectives: The most image watermarking techniques has nearly always been implemented in red, green and blue color space. This paper provides a method for inserting the QR code in the CIEXYZ color space to store metadata information. Methods/Statistical Analysis: This paper provides new QR code watermarking technique that is included in the low-frequency sub-bands through the haar wavelet transformation to CIE XYZ color space of the color image. Independent Component Analysis was applied to the watermark signal and to insert the QR code to the low frequency band of the host image. In the QR code extraction process, QR code was to be detected even without the image. Findings: The results of several experiments indicate that the proposed method provides unambiguous detection, imperceptibility, security, and robustness against JPEG compression, median filtering, different noise and image cropping attacks. Application/Improvements: This method can be utilized to insert the metadata into the digital content. The proposed method will be developed to be more robust to various attacks in the future. Keywords: Data Hiding, Metadata, QR Code, Watermark, Watermarking, Wavelet

Self-recovery scheme for audio restoration after a content replacement attack

Self-recovery schemes have been proposed for images and videos, however schemes for audio are intended to authenticate the contents or to localize tampering, but self-recovery for audio is still an open problem. This work presents a functional self-recovery scheme for audio that uses the intDCT domain for embedding and extraction of the control bits required to restore segments of an audio attacked with content replacement. Results obtained with the scheme are promising with regard to the quality of the watermarked signals; the scheme can restore signals attacked up to 0.6 % with acceptable quality. Further efforts should improve the restoration capabilities of the scheme.

Lossless visible watermarking based on adaptive circular shift operation for BTC-compressed images

Most existing BTC (Block Truncation Coding) based watermarking algorithms do not fully exploit visual perception of the host images. These schemes cannot obtain visual quality of stego-images and recover original images without distortion. To solve this issue, a new reversible visible watermarking scheme based on AMBTC (Absolute Moment Block Truncation Coding) domain is proposed. First, the proposed scheme uses adaptive pixel circular shift operation that adapts to local properties of the image to embed the visible watermark into two level (one-bit) nonparametric quantization levels of AMBTC according to the parity of the bit plane of AMBTC triple. The watermark signal can be extracted according to the parity of the Bit plane. The experimental results prove that the algorithm can achieve high visual quality of stego-images and recover original BTC-compressed image losslessly. Moreover, it is robust against common signal processing attacks. The visible watermarking algorithm can be applied to copyright of digital images in real-time environment because of the low time consumption due to the simplicity of AMBTC.

Optimal watermark embedding combining spread spectrum and quantization

This paper presents an optimal watermark embedding method combining spread spectrum and quantization. In the method, the host signal vector is quantized to embed a multiple-bit watermark, and meanwhile, the quantized signal is made to locate in the detectable region defined in the context of spread spectrum watermarking. Under the two constraints, the optimal watermarked signal is derived in the sense of minimizing the embedding distortion. The proposed method is further implemented in wavelet transform domain, where the insensitive wavelet coefficients are selected according to the modified human visual model for watermark embedding. Simulations on real images by using the wavelet-based implementations demonstrate the proposed method performs very well in both watermark imperceptibility and robustness and is more robust to typical signal processes, e.g., additive noise, JPEG compression, etc., as compared with the state-of-the-art watermarking methods.

Blind image counterwatermarking \u2013 hidden data filter

Watermarking is a dynamically developing method of copyright protection used for media (sounds, images, films, or 3D objects) that employs signal processing in order to hide additional, invisible information about the owner or author. However, studies until now have not widely considered the problem of attempting to blind removal of hidden data in a manner that allows the watermarked signal to be returned to the original signal. Current considerations of authors of leading articles in the watemarking field focus on the robustness of the method – security system against intentional attacks of removal of the additional information, without taking into account the aspect of simultaneous degradation of the quality and form of the watermarked picture. As has been shown in the article, it is possible to design a perfect filter (same as reversible operations) that allows the removal of additional information from the watermarked picture in a way that makes it possible to return to the form of the host image. This paper describes an ideal filter used for removal of additional, invisible information in forms of an eliminating function and a signal masking function. Their effectiveness has been demonstrated for practical implementations of this type of eliminating and masking filters for watermarking methods in the cepstrum domain.

SECURING MUSIC FOR COPYRIGHT PROTECTION

In recent times, due to the developments in technology the piracy process is less complicated and more common. There is a need to secure the digital data especially audio and in this paper we focus on methods to reduce piracy as well as unauthorized use of audio. Watermarking technique is one of the methods explained in this paper to overcome the above problem. There are different methods to watermark an audio signal, one such method is Phase Coding. In this method, the watermark signal is embedded in the phase of the host signal. The watermark signal is extracted from the attacked audio signal to prove the ownership or the authenticity of the audio signal.

Spread spectrum audio watermarking based on perceptual characteristic aware extraction

This study presents a high-performance audio watermarking scheme using spread spectrum modulation. Unlike conventional extractors which use simple correlation, this watermarking scheme exploits the perceptual characteristic of the watermarked audio before correlation. It is noted that although the watermark extractor works blindly neither which the original audio signal nor the embedded watermark signal is available, however, the spectral power structure of embedded watermark can be estimated using perceptual analysis methods. With this information, the watermark performance is improved by introducing an estimation-equalisation-correlation based extraction mechanism. The pre-equaliser at the extractor is carefully designed to obtain optimised extraction performance. Moreover, the perceptual analysis and shaping method are improved to make sure the watermark estimation is accurate. The perceptual characteristic aware extraction-based watermarking scheme achieves high embedding capacity up to 43 bps/channels, with low perceptual distortion to the host audio. Experiments on real audio signals show that the proposed watermarking scheme achieves high performance and is robust against various types of attacks.

A security watermark scheme used for digital speech forensics

Based on digital watermark, a speech forensics scheme is proposed. The feature coefficients cross-correlation degree of speech signal is defined, and the property is discussed, which demonstrates that the feature is very robust. Then a new watermark embedding method based on the feature is explored, aiming to enlarge the embedding capacity and solve the security issue of watermark schemes based on public features. In this paper, for each fame of speech signal, it is cut into two parts, and each part is divided into some segments. Then frame number is mapped to a sequence of integers, which are embedded into the segments. The integers can be extracted used for forensics and tamper location after watermarked signal being attacked. Theoretical analysis and experimental results show that the scheme proposed is inaudible and robust against desynchronization attacks, enhances the security of watermark system and has a good ability for speech forensics.