Digital watermarking is a key ingredient to copyright protection. It provides a solution to illegal copying of digital material and has many other useful applications such as broadcast monitoring and the recording of electronic transactions. Now, for the first time, there is a book that focuses exclusively on this exciting technology. Digital Watermarking covers the crucial research findings in the field: it explains the principles underlying digital watermarking technologies, describes the requirements that have given rise to them, and discusses the diverse ends to which these technologies are being applied. As a result, additional groundwork is laid for future developments in this field, helping the reader understand and anticipate new approaches and applications.

Digital Watermarking

Digital processing of speech signals

A color mapping process enhances a watermark by computing a change in colors that is less visible for a given watermark strength. The mapping process provides smooth transitions from one color region to another, and may be implemented efficiently with a 3D look up table. A user interface scheme enables the user to control encoding of the watermark in desired color regions.

Color adaptive watermarking

Today, a large number of audio features exists in audio retrieval for different purposes, such as automatic speech recognition, music information retrieval, audio segmentation, and environmental sound retrieval. The goal of this chapter is to review latest research in the context of audio feature extraction and to give an application-independent overview of the most important existing techniques. We survey state-of-the-art features from various domains and propose a novel taxonomy for the organization of audio features. Additionally, we identify the building blocks of audio features and propose a scheme that allows for the description of arbitrary features. We present an extensive literature survey and provide more than 200 references to relevant high-quality publications.

Features for Content-Based Audio Retrieval

Broadband communication networks and multimedia data available in a digital format opened many challenges and opportunities for innovation. Versatile and simple-to-use software and decreasing prices of digital devices have made it possible for consumers from all around the world to create and exchange multimedia data. Broadband Internet connections and near error-free transmission of data facilitate people to distribute large multimedia files and make identical digital copies of them. A perfect reproduction in digital domain have promoted the protection of intellectual ownership and the prevention of unauthorized tampering of multimedia data to become an important technological and research issue. Digital watermarking has been proposed as a new, alternative method to enforce intellectual property rights and protect digital media from tampering. Digital watermarking is defined as imperceptible, robust and secure communication of data related to the host signal, which includes embedding into and extraction from the host signal. The main challenge in digital audio watermarking and steganography is that if the perceptual transparency parameter is fixed, the design of a watermark system cannot obtain high robustness and a high watermark data rate at the same time. In this thesis, we address three research problems on audio watermarking: First, what is the highest watermark bit rate obtainable, under the perceptual transparency constraint, and how to approach the limit? Second, how can the detection performance of a watermarking system be improved using algorithms based on communications models for that system? Third, how can overall robustness to attacks to a watermark system be increased using attack characterization at the embedding side? An approach that combined theoretical consideration and experimental validation, including digital signal processing, psychoacoustic modeling and communications theory, is used in developing algorithms for audio watermarking and steganography. The main results of this study are the development of novel audio watermarking algorithms, with the state-of-the-art performance and an acceptable increase in computational complexity. The algorithms' performance is validated in the presence of the standard watermarking attacks. The main technical solutions include algorithms for embedding high data rate watermarks into the host audio signal, using channel models derived from communications theory for watermark transmission and the detection and modeling of attacks using attack characterization procedure. The thesis also includes a thorough review of the state-of-the-art literature in the digital audio watermarking.

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Algorithms for audio watermarking and steganography

We present a scheme for robust watermark insertion into video sequences. The proposed approach works in the uncompressed image domain, and it is robust against a large set of possible attacks. It has been developed for two principle applications: copyright protection and invisible embedding of indexing information. The proposed scheme has been tested and the results show that a robust watermark can be embedded in video sequences, and extracted after different attacks, in particular MPEG compression and geometrical attacks like cropping and resizing. We also compared two different error correcting codes used to improve robustness: convolutional and turbo codes.

A robust video watermarking technique in the spatial domain

The paper presents a wavelet domain watermarking technique for color images. The characteristics of this transform domain are well suited for masking consideration, due to its good localization in both space and frequency. The different color sensitivity can be exploited in order to increase the watermarking power, and therefore its reliability. Thanks to the multi-resolution nature of the discrete wavelet transform (DWT) the watermark detection can be obtained iteratively. The technique has been successfully evaluated against attacks such as JPEG and JPEG-2000 compression, filtering, cropping, dithering and digital to analog and analog to digital conversions.

A blind and readable watermarking technique for color images

We propose a watermarking scheme applied to digital audio signals. The goal of the project is to hide information which can identify both the tracks and the user who requests them. This technique is used for automatic identification of audio signals in broadcast programs. There are two main features that have to be satisfied: inaudibility and robustness to common editing operations. The algorithm works in a hybrid way: the watermark masking is in the frequency domain while the insertion is in the time domain. This approach allows detection to be performed directly in the time domain. In order to insert the watermark, the signal is split into frames, each of which hides binary information inserted using a spread spectrum sequence. To improve robustness, we use an error correcting code which allows the reduction of error probability. We discuss first the watermark embedding system, then the detection approach and finally the main results are presented.

http://ieeexplore.ieee.org/iel5/7973/22057/01026665.pdf

Embedding indexing information in audio signal using watermarking technique

We present a video watermarking technique proposed as an indexing technique for video sequences. The watermarking approach is based on an algorithm working in the spatial video domain, in order to reduce the computational cost, while the invisibility is obtained by masks computed in space and time domains. Finally, to improve robustness we work with different error correcting codes and we test their performances. The proposed scheme has been implemented and tested. Our tests are mainly focused on compression and transcoding attacks that are the most important operations that the video suffers in a journalistic report production. The robustness is increased by using an error correction code. The obtained results show that this is a good approach.

A robust video watermarking technique for compression and transcoding processing

This paper presents a hashing method for automatic song recognition. This technique works by analyzing the signal and taking into account its nature. The goal of automatic recognition is obtained by extracting different features, which are robust to signal processing and distinctive of the signal. They describe in a compact way the signal and can be efficiently stored in a database. The features are analyzed for short frames using a quantization approach, and a parameter for identification is proposed. Moreover we define also a confidence computed on the identification parameter. By combining the two parameters, a better identification is obtained. The algorithm is tested in different situations: compression, cropping, noise addition, subsampling, stereo to mono conversion, etc. The results show that the identification can be performed also using a short excerpt of the song

F. Mapelli

Papers

A robust video watermarking technique in the spatial domain

A blind and readable watermarking technique for color images

Embedding indexing information in audio signal using watermarking technique

A robust video watermarking technique for compression and transcoding processing

Audio content identification by using perceptual hashing