Koninklijke Philips Corporation N.v.

Koninklijke Phillips Electronics N.v.

Antonius A C M Kalker

Jaap Andre Haitsma

Johan P M G Linnartz

Geert F G Depovere

Maurice J J J-b Maes

Adrianus J M Denissen

Johan Cornelis Talstra

Marten Erik Van Dijk

Cornelis W A M Van Overveld

Nicolas Bailleul

Peter M J Rongen

Marc J R Op De Beeck

Adranius J M Denissen

Christianus W F Vriens

A method and arrangement for detecting a watermark embedded in an MPEG compressed signal includes a conventional MPEG decoder stripped to such an extent that a modified baseband video signal suitable for watermark detection is obtained. A plurality of pictures with the embedded watermark is accumulated () in the transform domain, and the inverse DCT () is applied to the accumulated result. Conventional watermark detection () is then applied to the accumulated plurality of pictures in the spatial domain.

Detection of a watermark in a compressed video signal

An MPEG video stream generator, which contains several slightly different programs, each with approximately the same content. The MPEG stream is constructed in such a manner that a simple transcoder can effectively select one of the programs. This is achieved by storing the differences relative to the default program in selected user data fields. The transcoder is little more than an MPEG bitstream parser, which replaces the bits corresponding to selected set of macroblocks by the replacement data stored in the user data fields. A standard MPEG decoder without any knowledge of the embedded user data fields will simply extracted the default program. One application relates to broadcasting of a television program with or without a logo, or a commercial with or without a public warning. Another application relates to copy-protection schemes. In such a scheme, the default program contains a ticket indicating that the contents may be copied once. Upon recording, this ticket is removed and replaced by the content accommodated in the user data field.

Video signal transmission

A method is disclosed for embedding auxiliary data in a signal. The data is encoded into the relative position or phase of one or more basic watermark patterns. This allows multi-bit data to be embedded by using only one or a few distinct watermark patterns.

Embedding auxiliary data in a signal

An improved method and arrangement for detecting a watermark in an information (e.g. image or video) signal are disclosed. The detection is more reliable and less vulnerable to image processing by partitioning the image into a sequence of blocks having a predetermined size, accumulating the blocks, computing a value indicative of the correlation of the accumulated blocks and the watermark having the predetermined size, and detecting whether the correlation value is larger than a predetermined threshold.

Watermark detection

The depth and orientation of a surface patch relative to a camera are determined. A first and second image of the surface patch are obtained from different viewpoints. Various predicted combinations of depth and orientation values are associated with the surface patch. Different available combinations may have different orientations. Each predicted combination predicts a correspondence between points in the first and second image, corresponding points viewing identical locations on the surface patch. One searches for a best combination of depth and orientation so that among the available combinations the best combination results in a minimum aggregate of differences between pixel values of the first and second image at corresponding points.

Method and device for optically determining depth

An input image is distorted so that it has less correlation to a watermark and the distorted image is subtracted from the input image to provide a preprocessed image. If the correlation between the preprocessed image and a watermark is sufficient then the watermark is detected in the input image. The distortion may be a spatially-variant distortion such as stretching, shrinking, shearing or rotation or the distortion may be a non-linear transforming or filtering such as median, local minimum or local maximum filtering.

An improved method and arrangement for detecting a watermark in an information (e.g. image or video) signal are disclosed. The detection is more reliable and less vulnerable to image processing by subjecting the suspect image (q) and the watermark to be detected (w) to Symmetrical Phase Only Matched Filtering ( ) prior to detecting ( ) the amount of correlation (d) between said signals.

A method and arrangement for detecting a watermark in an information signal. The method may include the steps of computing the correlation (d ) of the watermark (W ) and the information signal (e.g. an image Q) for a plurality of positions (k) of the watermark with respect to the information signal, and detecting whether at least one of the respective correlation values exceeds a given threshold. The step of detecting may include determining the standard deviation (&sgr; ) of the respective correlation values (d ), and setting the threshold to a given multiple (T) of the standard deviation. The multiple (T) is derived form a desired false alarm rate (watermark detected when there is none, or no watermark detected when there is one).

A watermark detector is disclosed to judge whether multimedia content can be copied or not. The watermark detector examines the multimedia content and outputs a signal indicating whether a watermark is present or not. A decision variable indicating to which extent the watermark is present is determined, for example, the amount of correlation between the input signal and a reference copy of the watermark to be detected. The watermark is detected if the decision variable exceeds a predetermined threshold (y ). The detector also generates a random output signal for a predetermined range of decision values between the threshold (y ) and a further threshold (y ).

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Eindhoven, Netherlands

Antonius A C M Kalker