Mitchell D. Swanson

Multimedia data-embedding and watermarking technologies

We review developments in transparent data embedding and watermarking for audio, image, and video. Data-embedding and watermarking algorithms embed text, binary streams, audio, image, or video in a host audio, image, or video signal. The embedded data are perceptually inaudible or invisible to maintain the quality of the source data. The embedded data can add features to the host multimedia signal, e.g., multilingual soundtracks in a movie, or provide copyright protection. We discuss the reliability of data-embedding procedures and their ability to deliver new services such as viewing a movie in a given rated version from a single multicast stream. We also discuss the issues and problems associated with copy and copyright protection and assess the viability of current watermarking algorithms as a means for protecting copyrighted data.

Robust audio watermarking using perceptual masking

Abstract We present a watermarking procedure to embed copyright protection into digital audio by directly modifying the audio samples. Our audio-dependent watermarking procedure directly exploits temporal and frequency perceptual masking to guarantee that the embedded watermark is inaudible and robust. The watermark is constructed by breaking each audio clip into smaller segments and adding a perceptually shaped pseudo-random sequence. The noise-like watermark is statistically undetectable to prevent unauthorized removal. Furthermore, the author representation we introduce resolves the deadlock problem. We also introduce the notion of a dual watermark: one which uses the original signal during detection and one which does not. We show that the dual watermarking approach together with the procedure that we use to derive the watermarks effectively solves the deadlock problem. We also demonstrate the robustness of that watermarking procedure to audio degradations and distortions, e.g., those that result from colored noise, MPEG coding, multiple watermarks, and temporal resampling.

Transparent robust image watermarking

We propose a watermarking scheme to hide copyright information in an image. The scheme employs visual masking to guarantee that the embedded watermark is invisible and to maximize the robustness of the hidden data. The watermark is constructed for arbitrary image blocks by filtering a pseudo-noise sequence (author id) with a filter that approximates the frequency masking characteristics of the visual system. The noise-like watermark is statistically invisible to deter unauthorized removal. Experimental results show that the watermark is robust to several distortions including white and colored noises, JPEG coding at different qualities, and cropping.

Multiresolution scene-based video watermarking using perceptual models

We present a watermarking procedure to embed copyright protection into digital video. Our watermarking procedure is scene-based and video dependent. It directly exploits spatial masking, frequency masking, and temporal properties to embed an invisible and robust watermark. The watermark consists of static and dynamic temporal components that are generated from a temporal wavelet transform of the video scenes. The resulting wavelet coefficient frames are modified by a perceptually shaped pseudorandom sequence representing the author. The noise-like watermark is statistically undetectable to thwart unauthorized removal. Furthermore, the author representation resolves the deadlock problem. The multiresolution watermark may be detected on single frames without knowledge of the location of the frames in the video scene. We demonstrate the robustness of the watermarking procedure to several video degradations and distortions.

Robust data hiding for images

Data hiding is the process of encoding extra information in an image by making small modifications to its pixels. To be practical, the hidden data must be perceptually invisible yet robust to common signal processing operations. This paper introduces two schemes for hiding data in images. The techniques exploit perceptual masking properties to embed the data in an invisible manner. The first method employs spatial masking and data spreading to hide information by modifying the image coefficients. The second method uses frequency masking to modify the image spectral components. By using perceptual masking, we also increase the robustness of the hidden information. Experimental results of data recovery after applying noise and JPEG coding to the hidden data are included.

Data hiding for video-in-video

We introduce a scheme for hiding high bit-rate supplementary data, such as secondary video, into a digital video stream by directly modifying the pixels in the video frames. The technique requires no separate channel or bit interleaving to transmit the extra information. The data is invisibly embedded using a perception-based projection and quantization algorithm. The data hiding algorithm supports user-defined levels of accessibility and security. We illustrate our algorithm using examples of real-time video-in-video and speech-in-video. We also demonstrate the robustness of the data hiding procedure to video degradation and distortion, e.g., those that result from additive noise and compression.

Object-based transparent video watermarking

We present a watermarking procedure to embed copyright protection into video sequences. To address issues associated with video motion and redundancy, individual watermarks are created for objects within the video. Each watermark is created by shaping an author and video dependent pseudo-random sequence according to the perceptual masking characteristics of the video. As a result, the watermark adapts to each video to ensure invisibility and robustness. Furthermore, the noise-like watermark is statistically undetectable. The watermark also resolves multiple ownership claims. We demonstrate the robustness of the watermarking procedure to video degradations, e.g., those that result from noise, MPEG compression, cropping, and printing and scanning.

A binary wavelet decomposition of binary images

We construct a theory of binary wavelet decompositions of finite binary images. The new binary wavelet transform uses simple module-2 operations. It shares many of the important characteristics of the real wavelet transform. In particular, it yields an output similar to the thresholded output of a real wavelet transform operating on the underlying binary image. We begin by introducing a new binary field transform to use as an alternative to the discrete Fourier transform over GF(2). The corresponding concept of sequence spectra over GF(2) is defined. Using this transform, a theory of binary wavelets is developed in terms of two-band perfect reconstruction filter banks in GF(2). By generalizing the corresponding real field constraints of bandwidth, vanishing moments, and spectral content in the filters, we construct a perfect reconstruction wavelet decomposition. We also demonstrate the potential use of the binary wavelet decomposition in lossless image coding.

Multiresolution video watermarking using perceptual models and scene segmentation

We introduce a watermarking procedure to embed copyright protection into digital video. Our video dependent watermarking procedure directly exploits the masking and temporal properties to embed an invisible and robust watermark. The watermark consists of static and dynamic temporal components that are generated from a temporal wavelet transform of the video scenes. To generate the watermark, the resulting wavelet coefficient frames are modified by a perceptually shaped pseudo-random sequence representing the author. The noise-like watermark is statistically undetectable to thwart unauthorized removal. Furthermore, the author representation resolves the deadlock problem. The multiresolution watermark may be detected on single frames without knowledge of the location of the frames in the video scene. We demonstrate the robustness of the watermarking procedure to several video distortions.

Current state of the art, challenges and future directions for audio watermarking

Transparent data embedding algorithms embed binary streams in host multimedia signals. The embedded data is perceptually inaudible to maintain the quality of the source data. The embedded data can add features to the host multimedia signal or provide copyright protection. We review developments and requirements in transparent data embedding techniques for audio signals. We describe our latest audio embedding algorithm and include experimental results indicating robustness to low bit rate MPEG-Layer 3, AAC, and Dolby AC-3 coding. We conclude with a discussion of future research directions.