Nedeljko Cvejic

Increasing the capacity of LSB-based audio steganography

Conventionally, a perceptual limit of three bits per sample is imposed to the basic LSB audio steganography method. In this paper, we present a novel modification to standard LSB algorithm that is able to embed four bits per sample, thus improving the capacity of data hiding channel by 33%. The proposed algorithm makes use of minimum error replacement method for LSB adjustment and modified error diffusion method for decreasing SNR value. Objective test showed the algorithm succeeds in this task, while keeping SNR value close to the level of SNR obtained by standard LSB embedding with three bits per sample capacity. Subjective listening test proved that high perceptual transparency is accomplished even if four LSBs of host audio signal are used for data hiding.

Increasing robustness of LSB audio steganography using a novel embedding method

We present a novel high bit rate LSB audio watermarking method. The basic idea of the proposed LSB algorithm is watermark embedding that causes minimal embedding distortion of the host audio. Using the proposed two-step algorithm, watermark bits are embedded into higher LSB layers, resulting in increased robustness against noise addition or MPEG compression. Listening tests showed that the perceptual quality of watermarked audio is higher in the case of the proposed method than in the standard LSB method.

Region-Based Multimodal Image Fusion using ICA Bases

In this paper, we present a novel multimodal image fusion algorithm in the independent component analysis (ICA) domain. Region-based fusion of ICA coefficients is implemented, where segmentation is performed in the spatial domain and ICA coefficients from separate regions are fused separately. The ICA coefficients from given regions are consequently weighted using the Piella fusion metric in order to maximize the quality of the fused image. The proposed method exhibits significantly higher performance than the basic ICA algorithm and also shows improvement over other state-of-the-art algorithms

A wavelet domain LSB insertion algorithm for high capacity audio steganography

In this work, we increased the capacity of the classic LSB insertion method by performing the embedding process in the wavelet domain. The algorithm uses perfect reconstruction filterbanks and embeds additional information inside wavelet domain of audio signal by modifying LSB values of wavelet coefficients. Objective and subjective tests show large advantage of the proposed method over time insertion method. For the same SNR values, proposed algorithm outperforms classical LSB algorithm by 150-200 kbps of hidden data. Subjective experiments showed that wavelet domain information hiding scheme is acoustically more transparent as well.

Spread spectrum audio watermarking using frequency hopping and attack characterization

In this paper, we present a novel audio watermarking scheme that uses attack characterization to obtain high robustness against standard watermark attacks. The watermark embedding and detection are based on the frequency hopping method in the spectral domain. Perceptual transparency of the algorithm, achieved using frequency masking property of the human auditory system, was confirmed throughout listening tests. Detection robustness of the proposed scheme with and without attack characterization module was compared to standard direct sequence approach. Tests showed that the proposed method obtains higher robustness to standard watermarking attacks and that the attack characterization module significantly improves the performance of both algorithms.

Audio watermarking using m-sequences and temporal masking

A novel algorithm for embedding a spread-spectrum based watermark into uncompressed, raw audio sequences is presented. The scheme takes advantage of temporal masking phenomenon in the human auditory system (HAS) in order to embed watermark data below the masking threshold of the audio signal. Detection of the watermark is done by blind detection, without using the original audio. As watermarking embedding and extraction are performed in the temporal domain, transformations to and from the frequency domain are not performed, neither on the embedding nor extraction part of the proposed scheme, resulting in the calculation simplicity of the embedding and detection process. The algorithm proved to be robust against mp3 compression (resulting in a BER of about 1.7%) and other common signal processing attacks, while the embedded watermark introduces no audible distortion of the host audio signal.

Digital Audio Watermarking Techniques and Technologies: Applications and Benchmarks

Digital audio watermarking has been proposed as a new and alternative method to enforce intellectual property rights and protect digital audio from tampering. Digital Audio Watermarking Techniques and Technologies: Applications and Benchmarks is a comprehensive compilation of the major theoretical frameworks, research findings, and practical applications. With inclusive coverage of the most authoritative research in the area, Digital Audio Watermarking Techniques and Technologies: Applications and Benchmarks will serve as a vital reference to researchers and practitioners in a variety of disciplines, including engineering, information technology, and digital audio. With value to a diverse range of users, this Premier Reference Source suits libraries in numerous settings.

Channel capacity of high bit rate audio data hiding algorithms in diverse transform domains

In this paper, we present analysis of the achievable watermark channel data rate in high data rate data hiding applications. As the perceptual entropy for wideband monophonic audio signals is in the range of 4-5 bps, for an uncompressed audio signal, a significant amount of additional information can be inserted into the signal without causing a perceptual distortion. Test results showed that transform domain watermark embedding outperforms significantly watermark embedding in the time domain and that signal decompositions with a high GTC, like the wavelet transform, are the most suitable for high data rate information hiding applications.

Reduced distortion bit-modification for LSB audio steganography

In this paper, we present a novel high bit rate LSB audio data hiding method that reduces embedding distortion of the host audio. Using the proposed two-step algorithm, hidden bits are embedded into the higher LSB layers, resulting in increased robustness against noise addition. In addition, listening tests showed that perceptual quality of watermarked audio is higher in the case of rite proposed method than the perceptual quality obtained using the standard LSB method.

A Nonreference Image Fusion Metric Based on the Regional Importance Measure

In this paper, we present a novel metric for evaluation of image fusion algorithms, based on evaluation of similarity of regions in images to be fused with the corresponding regions in the fused image. The metric uses several factors to quantify the importance of regions in each of the input images, such as contrast, size, and shape of region. The similarity of the corresponding regions in an input image and the fused image is measured using a wavelet-based mutual information measure. Experimental results show that the proposed metrics ranking of different image fusion methods is more consistent with the subjective quality of the fused image than the state-of-the-art image fusion metrics.