Progressive watermark decoding on a distributed computing platform

• US 20050036653A1
• Filed: 04/20/2004
• Published: 02/17/2005
• Est. Priority Date: 10/16/2001
• Status: Active Grant

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Brundage, Trent J., Sharma, Ravi K., Hannigan, Brett T.
• Granted Patent: US 7,227,972 B2
• Time in Patent Office: Days
• US Class Current: 382/100
• 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 disclosure describes a method of progressively decoding a digital watermark on a distributed computing platform. A client device equipped with a digital camera, such as a PDA or cell phone, captures a digital image of a watermarked object, and pre-filters the image to isolate a portion of the image data suspected of containing a digital watermark. The pre-filter de-correlates a portion of the image data suspected of containing a digital watermark from the remaining host image signal using a predictive filter. The client then quantizes the filtered data and progressively transmits the quantized data to a watermark decoder. The progressive transmitter sends image data as necessary to achieve a valid decoding operation. To reduce bandwidth requirements, the transmitter starts with the most highly quantized version of the filtered image, and sends lesser quantized versions until the watermark decoder completes a successful decoding operation.

Claims

1. A method of processing a digitally watermarked media signal, the method comprising:

receiving a watermarked media signal;

filtering the watermarked media signal to leave a residual signal from which a digital watermark is decoded;

sending the filtered signal to a remote system for extracting the digital watermark from the residual signal.

2. The method of claim 1 including:

progressively sending residual signals in more detail to the remote system.

3. The method of claim 1 wherein the residual signal comprises a quantized version of the watermarked media signal.

4. The method of claim 1 including:

transforming the watermarked signal into a domain in which the digital watermark is embedded before sending the filtered signal to the remote system.

5. The method of claim 4 including transforming the watermarked signal into a color space.

6. The method of claim 1 including:

capturing the watermarked signal from a capture device.

7. The method of claim 6 wherein the capture device comprises a camera.

8. The method of claim 6 wherein the capture device comprises a microphone.

9. A storage medium on which is stored instructions for performing a method of processing a digitally watermarked media signal, the method comprising:

receiving a watermarked media signal;

filtering the watermarked media signal to leave a residual signal from which a digital watermark is decoded;

sending the filtered signal to a remote system for extracting the digital watermark from the residual signal.

10. A method of processing a digitally watermarked media signal, the method comprising:

receiving a watermarked media signal;

identifying portions of the watermarked media signal to send to a remote system for watermark decoding; and

progressively sending the portions of the watermarked media signal to the remote system for watermark decoding.

11. The method of claim 10 including:

identifying blocks of the watermarked signal that are likely to have a stronger watermark signal for sending to the remote system.

12. The method of claim 11 wherein the identifying includes analyzing signal metrics of the blocks and ranking the blocks for sending based on the signal metrics.

13. The method of claim 10 including:

progressively sending frames of the watermarked signal to the remote system for watermark decoding.

14. The method of claim 13 including progressively sending frames of images.

15. The method of claim 13 including:

progressively sending filtered frames of the watermarked signal.

16. A storage medium on which is stored instructions for performing a method of processing a digitally watermarked media signal, the method comprising:

receiving a watermarked media signal;

identifying portions of the watermarked media signal to send to a remote system for watermark decoding; and

progressively sending the portions of the watermarked media signal to the remote system for watermark decoding.