Abstract: The disclosure describes a method of progressively decoding a digital watermark on a distributed computing platform. A client device equipped with a digital camera, such as a PDA or cell phone, captures a digital image of a watermarked object, and pre-filters the image to isolate a portion of the image data suspected of containing a digital watermark. The pre-filter de-correlates a portion of the image data suspected of containing a digital watermark from the remaining host image signal using a predictive filter. The client then quantizes the filtered data and progressively transmits the quantized data to a watermark decoder. The progressive transmitter sends image data as necessary to achieve a valid decoding operation. To reduce bandwidth requirements, the transmitter starts with the most highly quantized version of the filtered image, and sends lesser quantized versions until the watermark decoder completes a successful decoding operation.

Abstract: A watermark system includes an embedder, detector, and reader. The watermark embedder encodes a watermark signal in a host signal to create a combined signal. The detector looks for the watermark signal in a potentially corrupted version of the combined signal, and computes its orientation. Finally, a reader extracts a message in the watermark signal from the combined signal using the orientation to approximate the original state of the combined signal. While adapted for images, video and audio, the watermark system applies to other electronic and physical media. For example, it can be applied to mark graphical models, blank paper, film and other substrates, texturing objects for ID purposes, etc.

Abstract: A watermark embedder decomposes a media signal from its perceptual domain to subbands and embeds a message signal in the edge information of neighboring coefficients of those subbands. A compatible watermark decoder decomposes the watermarked signal into subbands and demodulates the message signal from the edge information of neighboring coefficients. In addition to the message signal, the embedder may also encode an orientation signal to synchronize the decoder with the embedded signal in a distorted version of the watermarked signal. The watermark system may be used in a variety of applications, including robustly carrying metadata or links to metadata, and to detect alterations of the watermarked signal, such as alterations due to printing, scanning, compression, etc.

Abstract: A digital watermark reader performs a logarithmic sampling of a watermarked media signal to produce a sampled signal. It then analyzes the sampled signal to detect attributes associated with a watermark signal. It extracts a digital watermark based on detected attributes associated with the watermark signal. As an alternative or in addition to these operations, the watermark reader performs a polar sampling of the media signal. For example, polar sampling may be used to address rotational distortion. Another digital watermark reader transforms the media signal to a transform domain, and analyzes the transformed media signal to detect a symmetrical attribute associated with a watermark signal. The method extracts the digital watermark based on detected attributes associated with the watermark signal.

Abstract: One method for halftone image watermarking assigns halftone watermark dot values to pseudorandom locations in an image and diffuses the error of the watermark to neighboring pixel locations of these dots. This method may be used in conjunction with a robust watermark spread throughout image before embedding the halftone watermark. The robust watermark carries a key used to decode the halftone watermark. Another method for halftone image watermarking computes a watermark image at the resolution of a halftone image. The method modulates the halftone image with the watermark image.

Abstract: A watermark embedder transforms a media signal from its perceptual domain to frequency domain regions and embeds a hash of data from one frequency domain region into a watermark in another frequency domain region. Alternatively, it encodes instances of the same message into the frequency domain regions. To detect alteration of the media signal, a watermark decoder transforms a suspect signal into the frequency domain regions, extracts the watermark message from a first frequency domain region and compares it with a reference derived from another frequency domain region. The reference signal is either a hash computed from the other frequency domain region of the watermarked signal, or another instance of the same message embedded into the other frequency domain region. The decoder can be used to detect alteration of the signal, such as alteration that occurs with reproduction (printing, scanning, copying, D/A-A/D conversion, etc.), compression, cropping or swapping of media signal content, etc.

Abstract: Methods and systems for time-frequency domain watermarking of media signals, such as audio and video signals. An encoding method divides the media signal into segments, transforms each segment into a time-frequency representation, and computes a time-frequency domain watermark signal based on the time frequency representation. It then combines the time-frequency domain watermark signal with the media signal to produce a watermarked media signal. To embed a message using this method, one may use peak modulation, pseudorandom noise modulation, statistical feature modulation, etc. Watermarking in the time-frequency domain enables the encoder to perceptually model time and frequency attributes of the media signal simultaneously. A watermark decoder uses a calibration signal to detect the watermark signal in a potentially distorted version of the watermarked signal. The calibration signal may also be used to determine the watermark's alignment and scaling.

Abstract: A consumer audio device decodes auxiliary control data that is hidden in audio information. The auxiliary control information can be used to trigger some response in the device, such as enabling or disabling certain operations.

Abstract: A physical medium is encoded with machine readable information that provides a human interface to a computer system. The information encoded into the medium indicates a computer implemented process, and is encoded according to a spectral encoding scheme, such as encoding by modifying color values of a graphic or other image printed on the medium. For example, a digital watermark or other steganographic data hidden in the image indicates a web page. In response to the user selecting the encoded information area, the machine readable information is decoded, and used to invoke a computer implemented process.

Abstract: A perceptual model performs an analysis of a media signal, such as an image or audio signal. The model may be used in media signal processing applications such as digital watermarking and data compression to reduce perceptibility of changes made to code the signal. For image applications, the model computes the sensitivity of an image to changes based upon local image contrast, while taking into account the sensitivity of connected directional edges. By comparing the local image strength of various directionally filtered versions of the image, the model creates a directional control vector. This control vector may be used to reduce changes to an image in text and edge regions, and thus, avoid perceptible artifacts in those regions. The model takes into account the local contrast of the image and the directional control vector to create a gain vector. Using the local contrast measurements, the model follows the eye's nonlinear response to contrast discrimination.

Abstract: A perceptual model performs an analysis of a media signal, such as an image or audio signal. The model may be used in media signal processing applications such as digital watermarking and data compression to reduce perceptibility of changes made to code the signal. For image applications, the model computes the sensitivity of an image to changes based upon local image contrast, while taking into account the sensitivity of connected directional edges. By comparing the local image strength of various directionally filtered versions of the image, the model creates a directional control vector. This control vector may be used to reduce changes to an image in text and edge regions, and thus, avoid perceptible artifacts in those regions. The model takes into account the local contrast of the image and the directional control vector to create a gain vector. Using the local contrast measurements, the model follows the eye's nonlinear response to contrast discrimination.

Abstract: A method and system for embedding signatures within visual images in both digital representation and print or film. A signature is inseparably embedded within the visible image, the signature persisting through image transforms that include resizing as well as conversion to print or film and back to digital form. Signature points are selected from among the pixels of an original image. The pixel values of the signature points and surrounding pixels are adjusted by an amount detectable by a digital scanner. The adjusted signature points form a digital signature which is stored for future identification of subject images derived from the image. In one embodiment, a signature is embedded within an image by locating relative extrema in the continuous space of pixel values and selecting the signature points from among the extrema. Preferably, the signature is redundantly embedded in the image such that any of the redundant representations can be used to identify the signature.

Abstract: A watermarking method converts a watermark message into a Frequency Shift Keying (FSK) signal and embeds the FSK signal in a host signal. The spectral properties of the FSK watermark signal facilitate its detection, even in applications where the watermarked signal is corrupted. Because of these properties, the FSK watermark signal can perform the dual function of identifying the watermark's presence and orientation in potentially corrupted media, and also conveying a hidden message in the host signal. Such a watermark may be referred to as a self-orienting watermark.

Abstract: A watermark system includes an embedder, detector, and reader. The watermark embedder encodes a watermark signal in a host signal to create a combined signal. The detector looks for the watermark signal in a potentially corrupted version of the combined signal, and computes its orientation. Finally, a reader extracts a message in the watermark signal from the combined signal using the orientation to approximate the original state of the combined signal. While adapted for images, video and audio, the watermark system applies to other electronic and physical media. For example, it can be applied to mark graphical models, blank paper, film and other substrates, texturing objects for ID purposes, etc.

Abstract: A method for decoding auxiliary data from media signals in multimedia content decodes watermarks from different media signals and uses the watermarks to control processing of the multimedia content. A copy control method decodes a watermark from one of the media signals in multimedia content, and uses the watermark to control processing of the multimedia content. Another method uses a watermark decoded from a first media signal to decode a second media signal. Yet another method uses a watermark decoded from a media signal to decode metadata associated with the media signal. Finally, another method forms a key for decoding data from at least first and second watermarks extracted from first and second media signals.

Abstract: A watermark embedder encodes auxiliary information, such as a binary message, into a host media signal by modulating message signals with two or more corresponding carrier signals to form a watermark signal and embeds this signal into the host. A compatible watermark decoder uses the carrier signals to demodulate the message signals from the watermarked signal.

Abstract: 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.

Abstract: A signal embedder hides auxiliary data in a media signal such that the auxiliary data is humanly imperceptible yet recoverable by an automated auxiliary data reader. The embedding method comprises segmenting the media signal into regions, determining statistics for the regions, and adapting quantization bins for each region based on the statistics calculated for the region. To hide auxiliary data in the regions, the method quantizes signal characteristics in the regions into the quantization bins adapted for the regions. The quantization bins correspond to auxiliary data symbols and the signal characteristics are quantized into selected bins depending on the auxiliary data symbol to be embedded in the signal characteristics. A compatible reading method performs a similar adaptive process to define the quantization bins before mapping signal characteristics into the adapted bins to extract the hidden data.

Abstract: To permit scaling or rotation of an image to be discerned—even if the original image is not available—certain marker signals are steganographically encoded in the image. In one particular implementation, encoding is effected by adding an overlay signal to the image. The overlay signal—when represented in the spatial frequency domain—includes a pattern of spots. If the image is scaled or rotated, this pattern changes in known ways. By examining the change in this pattern, the distortion (i.e., scale/rotation) of the image can be inferred. This technology finds particular application in conjunction with watermarking systems, permitting recovery of watermark data from images that have been scaled or rotated subsequent to watermarking.

Abstract: An audio monitoring device includes a microphone for receiving sound energy from a loudspeaker, and a steganographic decoder that decodes the signal produced by the microphone. By reference to the steganographically-decoded information, the device can be used to monitor the musical selections played in a venue for copyright royalty purposes and the like.