System and method for digitally marking a file with a removable mark

• US 20040199772A1
• Filed: 04/20/2004
• Published: 10/07/2004
• Est. Priority Date: 04/06/1999
• Status: Active Grant

• Current Assignee: KWAN Software Engineering Incorporated
• Original Assignee: KWAN Software Engineering Incorporated
• Inventors: Kwan, John Man Kwong
• Granted Patent: US 8,285,995 B2
• Time in Patent Office: Days
• US Class Current: 713/176
• 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 20/00884 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 1/32203 Spatial or amplitude domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/32208 involving changing the magnitude of selected pixels, e.g. overlay of information or super-imposition H04N1/32219, H04N1/32224 take precedence
• CPC Class Codes: H04N 1/32229 with selective or adaptive application of the additional information, e.g. in selected regions of the image H04N1/32213 takes precedence
• CPC Class Codes: H04N 2005/91335 the copy protection signal being a watermark
• CPC Class Codes: H04N 2201/3226 of identification information or the like, e.g. ID code, index, title, part of an image, reduced-size image
• 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

A system enables encoding of a removable mark into digital data, and decoding of the mark from the digital data. The system comprises an encoder and a decoder. The encoder includes a target area locator for locating in digital data a predetermined pattern of values that represents a flat area, and a marker for modifying values in the flat area to encode a mark into the flat area. The decoder attempts to extract the mark from the digital data. The decoder includes a mark area locator for locating a predetermined pattern of values in digital data, and an unmarker coupled to the mark area locator for examining the values to determine the state of each value and extract an embedded mark from the predetermined pattern of values.

Claims

1. An apparatus for encoding a mark into digital data, comprising:

means for locating in the digital data, using a predetermined pattern, at least two values that represents a flat area; and

means for modifying the values in the flat area to encode a mark into the flat area;

wherein the means for locating in the digital data further comprises;

means for calculating a variability for a selected portion of the digital data using the predetermined pattern; and

means for representing the flat area when the variability is less than a predetermined amount;

wherein the apparatus for encoding is part of a device receiving an unencoded data to create the digital data; and

wherein the apparatus for encoding is part of the device using the values in the flat area to create an encoded data.

2. The apparatus of claim 115, wherein the predetermined pattern is a regular pattern.

3. The apparatus of claim 115, wherein the predetermined pattern is an irregular pattern.

4. The apparatus of claim 115, wherein the predetermined pattern identifies a consecutive set of values.

5. The apparatus of claim 115, wherein the means for modifying the values further comprises:

means for modifying the values according to a recognizable amount.

6. The apparatus of claim 119, wherein the means for modifying the values further comprises:

means for adding the recognizable amount to the values.

7. The apparatus of claim 119, wherein the means for modifying the values further comprises:

means for subtracting the recognizable amount from the values.

8. The apparatus of claim 119, further comprising the means for computing the recognizable amount includes:

a means for calculating a function of the variability in the flat area.

9. The apparatus of claim 122, wherein the means for computing the recognizable amount further comprises:

means for computing the recognizable amount as a multiple of the variability in the flat area.

10. The apparatus of claim 119, further comprising:

means for modifying the values in the flat area to provide at least one known peak in the flat area.

11. The apparatus of claim 115, wherein the means for modifying the values further comprises:

means for modifying at least two of the values in the digital data to represent a single mark value in the flat area.

12. The apparatus of claim 115, further comprising:

means for locating in the digital data, using a predetermined pattern, at least two values that represents a second flat area; and

means for modifying the values in the second flat area to encode the mark into the second flat area.

13. The apparatus of claim 115, further comprising:

means for converting the format of the digital data.

14. The apparatus of claim 115, at least one of the means is implemented using a computer accessing a memory.

15. The apparatus of claim 115, wherein the device is included in a computer receiving the unencoded data.

16. The apparatus of claim 115, wherein the device communicates with a processor within a computer to create the encoded data within the computer.

17. The apparatus of claim 115, wherein the predetermined pattern is one dimensional.

18. The apparatus of claim 115, wherein the predetermined pattern is two dimensional.

19. The method of claim 115, wherein the predetermined pattern is three dimensional.