Two Phillips Watermarking Patent Applications
On Thursdays the USPTO publishes new pending patent applications. Apparently watermarking continues to be apparently fertile ground for innovation. Both of Today's Spotlight Applications concern the use of watermarking and both are from Phillips. The first application discloses homomorphic encryption for secure watermarking. The second discloses
20080212780, "Homomorphic Encryption For Secure Watermarking," assigned to Phillips (NL).
Abstract
A method and a system for embedding a watermark in a media signal x are disclosed. The method comprises providing an at least partially encrypted media signal c.sub.x of said media signal x, wherein encryption is performed using a first encryption key k1; providing an at least partially encrypted watermark signal c.sub.w, wherein encryption is performed using a second encryption key k.sub.2; combining the at least partially encrypted media signal c.sub.x and the at least partially encrypted watermark signal c.sub.w in a combiner to obtain an encrypted combined media signal c.sub.y; and obtaining a decrypted watermarked media signal y by decrypting said encrypted combined media signal c.sub.y using a third decryption key k3. The present invention provides a framework for secure watermark embedding within untrusted devices.
20080215605, "Method for Embedding Data," assigned to Phillips.
Abstract
Watermarking schemes are known that embed the watermark directly in the MPEG domain. A requirement for these algorithms is that the watermarked MPEG stream does not increase in size. Therefore, a bit rate controller allows a modification of a DCT coefficient only if such modification does not increase the stream size. It happens frequently that DCT coefficients are skipped because of this requirement. As a direct consequence, the watermark energy is smaller than desired and therefore the watermark is less robust. This invention exploits the fact that stuffing bits have often already been added to the stream by the MPEG encoder. The embedder is arranged to analyse the stream so as to find out how many stuffing bits there are at the end of the slice. The embedder can then embed the watermark immediately at the beginning of a slice. As a direct result, the watermark energy will increase and therefore the watermark will be more robust.
Abstract
A method and a system for embedding a watermark in a media signal x are disclosed. The method comprises providing an at least partially encrypted media signal c.sub.x of said media signal x, wherein encryption is performed using a first encryption key k1; providing an at least partially encrypted watermark signal c.sub.w, wherein encryption is performed using a second encryption key k.sub.2; combining the at least partially encrypted media signal c.sub.x and the at least partially encrypted watermark signal c.sub.w in a combiner to obtain an encrypted combined media signal c.sub.y; and obtaining a decrypted watermarked media signal y by decrypting said encrypted combined media signal c.sub.y using a third decryption key k3. The present invention provides a framework for secure watermark embedding within untrusted devices.
20080215605, "Method for Embedding Data," assigned to Phillips.
Abstract
Watermarking schemes are known that embed the watermark directly in the MPEG domain. A requirement for these algorithms is that the watermarked MPEG stream does not increase in size. Therefore, a bit rate controller allows a modification of a DCT coefficient only if such modification does not increase the stream size. It happens frequently that DCT coefficients are skipped because of this requirement. As a direct consequence, the watermark energy is smaller than desired and therefore the watermark is less robust. This invention exploits the fact that stuffing bits have often already been added to the stream by the MPEG encoder. The embedder is arranged to analyse the stream so as to find out how many stuffing bits there are at the end of the slice. The embedder can then embed the watermark immediately at the beginning of a slice. As a direct result, the watermark energy will increase and therefore the watermark will be more robust.
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