SYSTEM AND METHOD FOR DETECTING THE WATERMARK USING DECISION FUSION

• US 20120300975A1
• Filed: 07/28/2011
• Published: 11/29/2012
• Est. Priority Date: 05/24/2011
• Status: Active Grant

• Current Assignee: TATA Consultancy Services Limited (Tata Sons Pvt Ltd.)
• Original Assignee: TATA Consultancy Services Limited (Tata Sons Pvt Ltd.)
• Inventors: CHALAMALA, Srinivasa Rao, DHILLON, Jyoti, KAKKIRALA, Krishna Rao, VENKATARAMANI, Krithika
• Granted Patent: US 8,666,111 B2
• Time in Patent Office: Days
• US Class Current: 382/100
• CPC Class Codes: G06F 18/254 of classification results, e.g. of results related to same input data
• CPC Class Codes: G06T 1/005 Robust watermarking, e.g. average attack or collusion attack resistant
• CPC Class Codes: G06T 2201/0065 Extraction of an embedded watermark; Reliable detection

Abstract

The present application provides a robust system and method for detecting the watermark in an electronic media, wherein the electronic media had gone through various kinds of attacks and their combinations thereof which may not be known while detecting the watermarks. The watermark detection system and method can be trained to detect or reject a particular pattern. The watermark detection system and method are based on correlation and are useful in any kind of digital watermarking applications. The watermark detection system and method perform well even when the amount of distortion is not precisely known, wherein the disclosure provides a set of templates or correlation filters, being designed for detection of watermark to cover any kind and combination of attacks. For synchronous attacks, the correlation filter designing is carried out dynamically. Particularly, the template i.e. correlation filter is an attack adaptive frequency domain pattern for watermark detection.

Claims

1. A method for detection of a plurality of attacks on a plurality of electronic media signals, characterized by a cross correlation based synchronous detection of watermark, the method comprising the computer implemented steps of:

extracting object electronic media signals from the compressed electronic media signals by employing at least one decompressing means;

instantaneously estimating plurality of parameters associated with at least one distortion or attack on the said object electronic media signals;

synchronously generating a set of plurality of candidate templates configured with a predictively designed cross correlation filter for an instantaneous estimation of possible type and strength of distortion, attacks and combination thereof for an optimal correlation performance of at least one template therefrom;

obtaining a Peak to Side lobe Ratio (PSR) score successively for each said template to determine a correlation output associated therewith each said template;

obtaining a maximum PSR score associated with each said template for each frame of the said electronic media signal that results into one classifier per frame, wherein each classifier is configured to detect the watermark in a frame for score commensurating with a predefined threshold value;

averaging the scores of the plurality of the classifiers associated with the plurality of frames of each said template;

applying at least one fusion rule adapted to compare the averaged classifier score with the predefined threshold value or alternatively evaluate the percentage of maximum classifiers associated with plurality of frames commensurating with the predefined threshold percentage thereof to determine the watermark status in the plurality of frames of the electronic media signal; and

deciding the presence of watermark, alternatively using at least one or combination of fusion rules, for determination of true positive associated with the attack.

2. The method of claim 1, wherein the attacks with the intention of removing the watermark comprises geometrical attacks including rotation, scaling, translation, shearing, random bending and change of aspect ratio, signal processing attacks including filtering and compression and cryptographic attacks including key search and oracle attacks.

3. The method of claim 1, wherein the said object electronic media signals comprises audio, video, image, speech, computer readable medium, Compact Disc (CD), hard disk, Floppy drive, any kind of document or combination thereof.

4. The method of claim 1, wherein the attack parameters estimation is carried by comprises a feature based image matching algorithm adapted to estimate a plurality of features associated with the attacks comprising estimation of incorporating amount of rotation, size scaling, cropping and signal processing algorithm adapted to estimate the type and amount of filtering used during the said attacks.

5. The method of claim 1, wherein the plurality of said candidate templates are predictively generated based on estimated characteristic of the attack or distortion resulting in determining the strength of the attack or distortion, each predictively generated template and combination thereof having optimal correlation performance corresponding to the detection of the watermark.

6. The method of claim 1, wherein upon estimation of the plurality of parameters, the plurality of said candidate templates are generated to configure possible combination of attacks until detection of true positive rate.

7. The method of claim 1, wherein the detection of watermark is based on the measurement of the correlation output of all the candidate templates with each frame of the said electronic media signal, the correlation output being processed with decision fusion rule to obtain probabilistic estimation detectability based on comparison of percentage of the PSR scores against the predetermined threshold percentage and alternatively an average of the maximum PSR scores against predetermined threshold percentage.

8. The method of claim 1, wherein the decision fusion rule for watermark detection facilitates low false positive rates of the classifier associated with each template.

9. A system for detection of a plurality of attacks on a plurality of electronic media signals, characterized by a computer implemented cross correlation based synchronous detection of watermark, the system comprises:

a plurality of object electronic media signals encrypted with one or more deterministic cryptographically secured random number sequences, at least one of the object electronic media signals being attacked with at least one type of attack or distortions;

at least one decompressing means for extracting each media signal from an object compressed electronic media signals;

an estimation means adapted to instantaneously estimate a plurality of parameters associated with at least one distortion or attack;

a template generation means adapted to synchronously generate a set of plurality of candidate templates in response to the estimated parameters, each template being a predictively designed cross correlation filter configurable for estimated possible type, strength of distortion, attacks and combination thereof for an optimal correlation performance of at least one template therefrom;

a correlation output determination means adapted to determine correlation output characterized by a Peak to Side lobe Ratio (PSR) score associated with each successive correlated template for each frame of the said electronic media signal and to derive a maximum PSR score associated with each frame for each candidate templates and to calculate an average maximum PSR score therefor;

a decision fusion module adapted to facilitate decision of presence of the watermark, compares percentage of maximum PSR scores associated with each frame for each template to commensurate with predefined threshold percentage and alternatively comparing the average of the maximum PSR scores associated with each frame for each template to commensurate with a predefined threshold value thereof; and

a watermark detection means adapted to detect the watermark, encrypted in each frame of the said electronic media signal, based on at least one or combination of the decision fusion outputs.

10. The system of claim 9, wherein the attacks for removing watermark comprises geometrical attacks including rotation, scaling, translation, shearing, random bending, and change of aspect ratio, signal processing attacks including filtering and compression and a cryptographic attacks including key search and oracle attacks.

11. The system of claim 9, wherein the object electronic media signal comprises audio, video, image, speech, computer readable medium, Compact Disc (CD), hard disk, Floppy drive, any kind of document or combination thereof.

12. The system of claim 9, wherein the attack parameters estimation means further comprising a feature based image matching algorithm adapted to instantaneously estimate a plurality of features associated with the plurality of synchronous attacks and combinations thereof comprising estimation of amount of rotation, size scaling and cropping and signal processing algorithms adapted to estimate the type and amount of filtering used during the attacks.

13. The system of claim 9, wherein the template generation means further adapted to generate the plurality of candidate templates dynamically based on estimation of the plurality of parameters associated with synchronous attacks.

14. The system of claim 9, wherein the correlation output determination means further comprises a score calculator adapted to instantaneously calculate a Peak to Side lobe Ratio (PSR) score associated with each successive correlated template for each frame of the said electronic media signal.

15. The system of claim 9, wherein the decision fusion module further adapted to instantaneously compare the percentage of processed correlation output scores associated with each frame for each template to commensurate with the predefined threshold percentage and alternatively compare the average of the maximum PSR scores associated with each frame for each template to commensurate with a predefined threshold value thereof, the decision fusion suggesting higher probability of the processed correlation output scores of detection based on percentage of maximum PSR score of each frame of at least one template and average thereof.

16. The system of claim 9, wherein the cross correlation filter comprises Random binary pattern trained to counter different attacks.

17. The system of claim 9, wherein the cryptographically secured random number sequences are generated by a deterministic random number generator using the Leibniz Pi infinite series.

18. The system of claim 9, wherein the watermark detection means is adapted to detect watermark for plurality of encryption modality of the media signals comprising encryption in a spatial domain, frequency domain, and time domain.