Image analysis – Applications
Reexamination Certificate
1999-04-27
2002-06-04
Johns, Andrew W. (Department: 2621)
Image analysis
Applications
Reexamination Certificate
active
06400826
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention generally relates to systems, methods, and products for watermarking of signals, and, more particularly, to computer-implemented systems, methods, and products for embedding an electronic form of a watermarking signal into an electronic form of a host signal.
2. Related Art
There is growing commercial interest in the watermarking of signals, a field more generally referred to as “steganography.” Other terms that refer to this field include “hidden communication,” “information hiding,” “data hiding,” and “digital watermarking.” Much of this interest has involved deterrence of copyright infringement with respect to electronically distributed material. Generally, the purpose of known steganographic systems in this field is to embed a digital watermark signal (for example, a serial number) in a host signal (for example, a particular copy of a software product sold to a customer). Other common host signals include audio, speech, image, and video signals. A purpose of many of such digital watermarking systems is to embed the watermark signal so that it is difficult to detect, and so that it is difficult to remove without corrupting the host signal. Other purposes are to provide authentication of signals, or to detect tampering.
Often, such known systems include “coding” functions that embed the watermark signal into the host signal to generate a composite signal, and “decoding” functions that seek to extract the watermark signal from the composite signal. Such functions may also be referred to as transmitting and receiving functions, indicating that the composite signal is transmitted over a channel to the receiver. Generally, the composite signal is suitable for the functions intended with respect to the host signal. That is, the host signal has not been so corrupted by the embedding as to unduly compromise its functions, or a suitable reconstructed host signal may be derived from the composite signal.
Although prevention of copyright infringement has driven much of the current interest in steganographic systems, other applications have also been proposed. For example, digital watermarking could be used by sponsors to automate monitoring of broadcasters' compliance with advertising contracts. In this application, each commercial is watermarked, and automated detection of the watermark is used to determine the number of times and time of day that the broadcaster played the commercial. In another application, captions and extra information about the host signal could be embedded, allowing those with the appropriate receivers to recover the information.
Various known approaches to the implementation of steganographic systems and simple quantization techniques are described in the following publications, which are hereby incorporated by reference: (1) N. S. Jayant and P. Noll, Digital Coding of Waveforms:
Principles and Applications to Speech and Video
. Prentice-Hall, 1984; (2) I. J. Cox, J. Killian, T. Leighton, and T. Shamoon, “A secure, robust watermark for multimedia,” in
Information Hiding. First International Workshop Proceedings
, pp.185-206, June 1996; (3) J. R. Smith and B. O. Comiskey, “Modulation and information hiding in images,” in
Information Hiding. First International Workshop Proceedings
, pp.207-226, June 1996; (4) W. Bender, D. Gruhl, N. Morimoto, and A. Lu, “Techniques for data hiding,”
IBM Systems Journal
, vol.35, no.3-4, pp.313-336, 1996; (5) L. Boney, A. H. Tewfik, and K. N. Hamdy, “Digital watermarks for audio signals,” in
Proceedings of the International Conference on Multimedia Computing and Systems
1996, pp.473-480, June 1996; (6) J.-F. Delaigle, C. D. Vleeschouwer, and B. Macq, “Digital watermarking,” in
Proceedings of SPIE, the International Society for Optical Engineering
, pp.99-110, Feb. 1996; (7) P. Davern and M. Scott, “Fractal based image steganography,” in
Information Hiding. First International Workshop Proceedings
, pp.279-294, June 1996, (8) R. Anderson, “Stretching the limits of steganography,” in
Information Hiding. First International Workshop Proceedings
, pp.39-48, June 1996; (9) B. Pfitzmann, “Information hiding terminology,” in
Information Hiding. First International Workshop Proceedings
, pp.347-350, June 1996; and (10) G. W. Braudaway, K. A. Magerlein, and F. Mintzer, “Protecting publicly-available images with a visible image watermark,” in
Proceedings of SPIE, the International Society for Optical Engineering
, pp.126-133, Febuary 1996.
Some of such known approaches may be classified as “additive” in nature (see, for example, the publications labeled 2-6, above). That is, the watermark signal is added to the host signal to create a composite signal. In many applications in which additive approaches are used, the host signal is not known at the receiving site. Thus, the host signal is additive noise from the viewpoint of the decoder that is attempting to extract the watermark signal.
Some of such, and other, known approaches (see, for example, the publications labeled 2, 4, 5, 6, and 7, above) exploit special properties of the human visual or auditory systems in order to reduce the additive noise introduced by the host signal or to achieve other objectives. For example, it has been suggested that, in the context of visual host signals, the watermark signal be placed in a visually significant portion of the host signal so that the watermark signal is not easily removed without corrupting the host signal. Visually significant portions are identified by reference to the particularly sensitivity of the human visual system to certain spatial frequencies and characteristics, including line and corner features. (See the publication labeled 2 , above.) It is evident that such approaches generally are limited to applications involving the particular human visual or auditory characteristics that are exploited.
One simple quantization technique for watermarking, commonly referred to as “low-bit coding” or “low-bit modulation,” is described in the publication labeled 4, above. As described therein, the least significant bit, or bits, of a quantized version of the host signal are modified to equal the bit representation of the watermark signal that is to be embedded.
SUMMARY
The present invention includes in some embodiments a system, method, and product for (1) optionally pre-processing one or more primary signals to generate a transformed host-signal and/or a transformed watermark-signal; (2) embedding one or more watermarked signals and/or transformed watermark signals into a host signal and/or the transformed host signal, thereby generating a composite signal, (3) optionally performing distortion compensation on the composite signal, thereby generating a distortion-compensated composite signal, (4) optionally enabling the composite signal, the digtortion-compensated composite signal, or both, to be transmitted over a communication channel, and (5) optionally extracting the watermark signal from the transmitted composite signal, distortion-compensated composite signal, or both.
More specifically, with respect to point (3), the present invention may include a distortion compensator that performs distortion compensation on the composite signal to generate a distortion-compensated composite signal that is less distorted than the composite signal. In some implementations, the distortion compensator includes a difference signal generator that generates a signal that is a difference between a host signal and a composite signal, a difference signal processor that scales the difference signal, and a distortion compensation combiner that generates a distortion-compensated composite signal based on the scaled difference signal and the composite signal
332
. This combination of signals may be done by addition. Optionally, the distortion-compensated composite signal may be generated based on the host signal and quantization values generated by an ensemble designator.
In one implementation, the invention is a distortion-compensated system that watermarks a host signal with a
Chen Brian
Wornell Gregory W.
Johns Andrew W.
Massachusetts Institute of Technology
Nakhjavan Shervin
Wolf Greenfield & Sacks P.C.
LandOfFree
System, method, and product for distortion-compensated... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System, method, and product for distortion-compensated..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System, method, and product for distortion-compensated... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2919032