Content Serialization by Varying Content Properties, Including Varying Master Copy Watermark Properties

• US 20090116686A1
• Filed: 10/03/2008
• Published: 05/07/2009
• Est. Priority Date: 10/05/2007
• Status: Active Grant

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Samtani, Rajan, Sharma, Ravi K., Meyer, Joel R.
• Granted Patent: US 10,129,429 B2
• Time in Patent Office: Days
• US Class Current: 382/100
• CPC Class Codes: G06F 21/10 Protecting distributed programs or content, e.g. vending or licensing of copyrighted material protection in video systems or pay television H04N7/16 ; Digital rights management [DRM]
• CPC Class Codes: G06T 1/0028 Adaptive watermarking, e.g. Human Visual System [HVS]-based watermarking
• CPC Class Codes: G06T 2201/0051 Embedding of the watermark in the spatial domain
• CPC Class Codes: G06T 2201/0061 Embedding of the watermark in each block of the image, e.g. segmented watermarking
• CPC Class Codes: G06T 2201/0064 for copy protection or copy management, e.g. CGMS, copy only once, one-time copy
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/00869 wherein the remote server can deliver the content to a receiving device
• CPC Class Codes: G11B 20/00884 involving a watermark, i.e. a barely perceptible transformation of the original data which can nevertheless be recognised by an algorithm
• CPC Class Codes: H04N 1/32149 Methods relating to embedding, encoding, decoding, detection or retrieval operations
• CPC Class Codes: H04N 1/32299 using more than one embedding method
• CPC Class Codes: H04N 19/467 characterised by the embedded information being invisible, e.g. watermarking
• CPC Class Codes: H04N 2201/3233 of authentication information, e.g. digital signature, watermark
• CPC Class Codes: H04N 2201/327 which are undetectable to the naked eye, e.g. embedded codes

Abstract

This disclosure describes novel methods for generating unique copies of content. One method combines the functions of the master copy and unique copy watermarks. In particular, the method generates a unique copy by varying the manner in which the master copy watermark is embedded in unique copies of a content item. In one embodiment, the master copy watermark is repeated within the content item and its location is varied in a unique pattern that comprises the unique copy watermark. The unique copy is generated by producing a copy in which master copy watermarks are embedded in a unique pattern. For instance in one embodiment, the locations of the master copy watermarks in the content item are represented as a vector of delta values in which each delta value corresponds to the distance between a corresponding instance of the master copy watermark, and a neighboring instance of the master copy watermark. This vector is stored in a transaction record in association with transaction information, such as information identifying the master copy and information associated with the unique copy. Other ways of representing the unique pattern of attributes of the master copy watermark are also possible. In other embodiments, properties of the master copy watermark other than its location are varied through the content. The unique copy watermark is conveyed in the vector of deltas in these properties of the master copy watermark. Some examples of these properties of the master copy watermark signal include phase characteristics (e.g., the phase shift of a watermark carrier signal), frequency magnitude characteristics, etc. These properties are varied in a manner that does not alter the information carried in the master copy watermark. However, it does provide a variation that creates a unique copy, and the unique copy watermark is conveyed in this variation. The variation in location of the instances of the master copy watermark can be in different domains, such as a spatial domain, a time domain, a time-space domain, a transform domain (including frequency transform domains), a compressed domain, etc.

Claims

1. A method of serializing a content item comprising:

evaluating a master copy of the content item to determine locations for altering the master copy; and

generating a unique copy of the content item from a master copy by altering the master copy at the locations, the alterations forming a pattern that comprises a unique copy watermark.

2. The method of claim 1 wherein the alterations comprise variations in embedding a master copy watermark.

3. The method of claim 1 wherein the alterations comprise variations in a property of a master copy watermark that is embedded at the locations.

4. The method of claim 3 wherein the locations comprise frequency locations.

5. The method of claim 3 wherein the locations comprise temporal locations.

6. The method of claim 3 wherein the variations comprise removal of a component of a master copy watermark.

7. A computer readable medium on which is stored instructions, which, when executed by a computer, perform the method of claim 1.

8. A method of serializing a content item comprising:

providing a master copy watermark for the content item; and

embedding instances of the master copy watermark in the content item, wherein a unique copy of the content item is generated by altering instances of the master copy watermark, the alterations of the master copy watermark forming a pattern that comprises a unique copy watermark.

9. The method of claim 8 wherein the alterations comprise omissions or removal of selected components of instances of the master copy watermark.

10. The method of claim 8 wherein the alterations comprise altering locations of the master copy watermark.

11. The method of claim 10 wherein the locations comprise frequency locations.

12. The method of claim 8 wherein the alterations comprise altering properties of the master copy watermark over instances of the master copy watermark.

13. The method of claim 8 wherein the alterations comprise substituting different values within the master copy watermark.

14. A computer readable medium on which is stored instructions, which, when executed by a computer, perform the method of claim 8.

15. A method of uniquely identifying a copy of a content signal from among copies of the same content signal, the method comprising:

detecting instances of a master copy watermark in the copy of the content signal;

determining a property of the instances of the master copy watermark signal that varies over the instances; and

based on variations in the property, computing a unique identifier of the copy of the content signal.

16. The method of claim 15 wherein the property comprises a location of an instance of the master copy watermark.

17. The method of claim 15 wherein the property comprises a frequency component of an instance of the master copy watermark.

18. The method of claim 17 wherein the property comprises an omitted or substituted frequency component.

19. The method of claim 15 wherein the property changes relative to a reference for different instances of the master copy watermark.

20. A computer readable medium on which is stored instructions, which, when executed by a computer, perform the method of claim 15.