Method and apparatus for detecting processing stages applied to a signal

• US 7,046,808 B1
• Filed: 03/24/2000
• Issued: 05/16/2006
• Est. Priority Date: 03/24/2000
• Status: Expired due to Fees

• Current Assignee: Verance Corporation
• Original Assignee: Verance Corporation
• Inventors: Petrovic, Rade, Jemili, Kanaan, Metois, Eric
• Primary Examiner(s): Song, Hosuk
• Application Number:
  US09/535,154
• Time in Patent Office: 2,244 Days
• Field of Search: 713/176, 713/200, 713/201, 380252-253, 380/100, 380200-205, 380/54, 380/217, 380236-238, 380/287, 705 57- 59, 726/26, 726/31, 382/100
• US Class Current: 380/252
• CPC Class Codes: G06T 1/0028 Adaptive watermarking, e.g. Human Visual System [HVS]-based watermarking
• CPC Class Codes: G06T 1/0042 Fragile watermarking, e.g. so as to detect tampering
• CPC Class Codes: G06T 2201/0202 whereby the quality of watermarked images is measured; Measuring quality or performance of watermarking methods; Balancing between quality and robustness
• CPC Class Codes: H04N 1/32144 embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
• CPC Class Codes: H04N 1/32154 Transform domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/32187 with selective or adaptive application of the additional information, e.g. in selected frequency coefficients
• CPC Class Codes: H04N 1/32299 using more than one embedding method
• CPC Class Codes: H04N 1/32304 Embedding different sets of additional information
• CPC Class Codes: H04N 1/3232 Robust embedding or watermarking
• CPC Class Codes: H04N 1/32331 Fragile embedding or watermarking
• CPC Class Codes: H04N 1/32352 Controlling detectability or arrangements to facilitate detection or retrieval of the embedded information, e.g. using markers for decoding, detection or retrieval operations H04N1/32149 and subgroups take precedence

Abstract

A system for determining the amount of processing that has been applied to watermarked signal. A steganographic signal is provided that includes an original signal and an embedded fragile watermark. The fragile watermark is characterized by a low energy and a high redundancy in comparison to a robust watermark. The steganographic signal is communicated over a distribution channel to a decoder. At the decoder, a measure of a presence of the fragile watermark in the acquired steganographic signal is provided, along with an estimate of the fragility profile of the fragile watermark for this particular original signal. Based on these factors, a estimate is made of the amount of processing that the steganographic signal has undergone. This processing can include, for example, A/D and D/A conversions, resampling, band-limiting, perceptual compression/decompression, etc. Optionally, the fragility profile is derived prior to the distribution of the content and communicated by the steganographic signal for recovery by the decoder. Furthermore, a robust watermark may be provided in the steganographic signal that, e.g., designates the presence of the fragile watermark to a decoder.

Claims

1. A method for using a watermark to estimate a nature and/or an amount of processing that is applied to a signal, comprising the steps of:

embedding a watermark with a degree of redundancy into the signal to form a steganographic signal;

measuring a deterioration of the embedded watermark in the steganographic signal after the steganographic signal undergoes the processing, said deterioration of the embedded watermark being based on recovered data bits from a plurality of said redundantly embedded watermarks; and

estimating the nature and/or the amount of the processing based on the measured deterioration.

2. The method of claim 1, wherein:

said estimating step estimates an intrinsic fragility of the watermark by analyzing characteristics of the steganographic signal.

3. The method of claim 1, comprising the further step of:

controlling an output of the steganographic signal when the amount of the estimated processing exceeds a threshold level.

4. The method of claim 1, wherein:

the nature and/or the amount of the estimated processing indicates whether the steganographic signal has undergone unauthorized processing.

5. The method of claim 1, wherein:

a user acquires the steganographic signal after it undergoes the processing; and

the nature and/or the amount of the estimated processing indicates whether the acquired steganographic signal closely matches the steganographic signal before it undergoes the processing.

6. The method of claim 5, comprising the further step of:

providing a message to the user indicating whether the acquired steganographic signal closely matches the steganographic signal before it underwent the processing.

7. The method of claim 1, wherein the processing that the steganographic signal undergoes comprises at least one of:

multi-generational copying;

perceptual compression and decompression;

digital-to-analog and analog-to-digital conversion;

resampling;

a bit depth reduction;

band-limiting;

dynamic range reduction; and

transmission over a communication channel.

8. The method of claim 1, wherein:

the deterioration of the embedded watermark is measured in accordance with a fragility profile of the embedded watermark.

9. The method of claim 8, wherein:

the fragility profile denotes a relationship between a bit error rate of the watermark and a signal to noise ratio of the steganographic signal.

10. The method of claim 1, wherein:

the watermark is embedded in the signal in accordance with a predicted sensitivity of the signal that is based on a psychoacoustic analysis thereof.

11. The method of claim 1, wherein:

the steganographic signal further includes an embedded robust watermark that signals a receiver that the watermark with redundancy is present in the steganographic signal.

12. The method of claim 1, wherein:

the steganographic signal comprises at least one of audio and video content.

13. A method for providing a signal with a watermark layer, comprising the steps of:

analyzing an intrinsic fragility of the signal, which is a carrier of the watermark layer; and

determining a fragility profile in response to said analyzing step;

wherein the fragility profile denotes a relationship between a bit error rate of the watermark layer and a signal to noise ratio of the signal after the watermark layer and the signal are degraded.

14. The method of claim 13, wherein the watermark layer is embedded into the signal to form a steganographic signal, comprising the further step of:

subjecting the steganographic signal to at least one processing step;

wherein the fragility profile denotes a deterioration of the embedded watermark layer due to said at least one processing stage.

15. The method of claim 13, wherein:

the intrinsic fragility analysis is applied to a cover portion of the signal before the signal is degraded by at least one processing step to indicate whether or not the watermark layer will survive the processing step.

16. The method of claim 15, comprising the further step of:

increasing a power of the watermark layer in the signal before the signal is degraded by the processing step if the intrinsic fragility analysis indicates that the watermark layer will not survive the processing step.

17. The method of claim 13, wherein:

the intrinsic fragility analysis is applied to a cover portion of the signal to suggest eventual modifications of a configuration of a watermarking system used to provide the watermark layer to ensure a survival of the watermark layer through a specified processing stage.

18. The method of claim 13, wherein:

after the analyzing and determining steps, the signal, and data designating the fragility profile, are distributed to a decoder.

19. The method of claim 18, wherein:

the data designating the fragility profile is carried in the signal.

20. The method of claim 18, wherein:

the data designating the fragility profile is carried in the signal in another watermark layer.

21. An apparatus for using a watermark to estimate a nature and/or an amount of processing that is applied to a signal, comprising:

means for embedding a watermark with a degree of redundancy into the signal to form a steganographic signal;

means for measuring a deterioration of the embedded watermark in the steganographic signal after the steganographic signal undergoes the processing, said deterioration of the embedded watermark being based on recovered data bits from a plurality of said redundantly embedded watermarks; and

means for estimating the nature and/or the amount of the processing based on the measured deterioration.

22. An apparatus for providing a signal with a watermark layer, comprising:

means for analyzing an intrinsic fragility of the signal, which is a carrier of the watermark layer; and

means for determining a fragility profile in response to said analyzing step;

wherein the fragility profile denotes a relationship between a bit error rate of the watermark layer and a signal to noise ratio of the signal after the watermark layer and the signal are degraded.