Encoding and Decoding Auxiliary Signals

• US 20100322468A1
• Filed: 04/27/2010
• Published: 12/23/2010
• Est. Priority Date: 04/25/2001
• Status: Active Grant

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Stach, John, Sharma, Ravi K.
• Granted Patent: US 8,170,273 B2
• Time in Patent Office: Days
• US Class Current: 382/100
• CPC Class Codes: G06T 1/0064 Geometric transfor invariant watermarking, e.g. affine transform invariant
• CPC Class Codes: G06T 2201/0052 Embedding of the watermark in the frequency domain

Abstract

This disclosure describes apparatus and systems for encoding and decoding signals from a host signal such as audio, video or imagery. One claim recites an apparatus comprising: electronic memory for storing a media signal representing audio or video; and an electronic processor. The electronic processor is programmed for: extracting data representing at least some features of the media signal; using the extracted data as a key to select coefficients in a transform domain, the coefficients representing the media signal; and modifying selected coefficients to hide a steganographic signal in the media signal. Of course, other claims and combinations are provided as well.

Claims

1. An apparatus comprising:

electronic memory for storing a media signal representing audio or video;

an electronic processor programmed for;

extracting a reduced-bit representation of the media signal;

adapting a digital watermark embedding process with the reduced-bit representation of the media signal; and

embedding a digital watermark in the media signal with the influenced digital watermark embedding process.

2. The apparatus of claim 1 wherein the watermark embedding process embeds at least a reference signal in the media signal that is used to correct or compensate for geometric distortion.

3. The apparatus of claim 2 in which the reduced-bit representation is used to generate the reference signal.

4. The apparatus of claim 1 in which the reduced-bit representation comprises a hash, and said embedding uses the hash as a key to encode a reference signal in data representing the media signal.

5. An apparatus comprising:

electronic memory for storing a media signal representing audio or video;

an electronic processor programmed for;

extracting a reduced-bit representation of the media signal;

influencing a digital watermark embedding process with the reduced-bit representation of the media signal by using the reduced-bit number to seed a pseudorandom number generate a reference signal; and

embedding a digital watermark in the media signal, in which said embedding embeds at least the reference signal in the media signal, the reference signal provide information for correcting or compensating for geometric distortion.

6. An apparatus comprising:

electronic memory for storing a media signal representing audio or video;

an electronic processor programmed for;

extracting data representing at least some features of the media signal;

using the extracted data as a key to select coefficients in a transform domain, the coefficients representing the media signal; and

modifying selected coefficients to hide a steganographic signal in the media signal.

7. The apparatus of claim 6 in which the key is further used to generate random phase information of a reference signal in the first transform domain, and in which said electronic processor is programmed for embedding the reference signal in the media signal.

8. An apparatus comprising:

electronic memory for storing a media signal comprising an auxiliary signal, the media signal comprising audio or video;

an electronic processor programmed for;

extracting data representing at least some features of the media signal;

influencing detection of the auxiliary signal with the data, in which the data seeds a pseudorandom number generator, a result of the pseudorandom number generator provides information used for detection; and

analyzing the media signal to detect the auxiliary signal with the information from the pseudorandom number generator.