Assessing quality of service using digital watermark information

• US 7,656,930 B2
• Filed: 10/02/2007
• Issued: 02/02/2010
• Est. Priority Date: 09/10/2001
• Status: Expired due to Term

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Levy, Kenneth L., Tian, Jun, Brunk, Hugh L.
• Primary Examiner(s): Tran; Khanh C
• Application Number:
  US11/866,145
• Publication Number:
  US 20080137749A1
• Time in Patent Office: 854 Days
• Field of Search: None
• US Class Current: 375/130
• CPC Class Codes: G06T 1/0021 Image watermarking
• CPC Class Codes: H04N 17/004 for digital television systems
• CPC Class Codes: H04N 21/4425 Monitoring of client processing errors or hardware failure
• CPC Class Codes: H04N 21/8358 involving watermark protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467

Abstract

The disclosure details methods of measuring the quality of service of received media signals by analyzing digital watermarks embedded in such signals. The quality of a received video or audio signal can thereby be assessed without having the original version of the signal before transmission. Instead, the strength or quality of the embedded digital watermark is analyzed to determine the quality of the received signal. The degradation of a watermark signal is used to assess quality of service of signals, such as audio and video.

Claims

1. A method of measuring quality of service of a received media signal using a digital watermark embedded in the media signal, the media signal representing audio and/or video information, the method comprising:

receiving a media signal transmitted over a communication channel from a transmitter, wherein the channel from the transmitter is susceptible to occasional distortion, causing degradation in quality of service;

extracting a digital watermark from the received media signal; and

evaluating the extracted digital watermark relative to a reference digital watermark to measure degradation in quality of service of the media signal based on differences between the extracted and reference digital watermarks, wherein said evaluating act is performed by a combination of hardware and software, and includes comparing signal peaks of the media signal and the reference digital watermark.

2. The method of claim 1 wherein the signal peaks comprise frequency domain peaks.

3. A method of assessing quality of service of a received media signal, the media signal representing audio and/or video information, the method including:

applying a digital watermark decoding process to the received media signal to sense a sequence of soft data bits; and

applying said sequence of sensed bits to an error correction decoder, yielding an error-corrected message payload;

wherein the sequence of soft data bits that yielded the error-corrected message payload indicates the degree of degradation of the media signal since its original watermark encoding; and

wherein the applying acts are performed by a combination of hardware and software.

4. A method of encoding content with a digital watermark, the content comprising audio or video information, the method including:

generating key data though a process that includes applying a perceptual hashing function to the content;

using said key data to scramble or encrypt a message, the message comprising a watermark payload and corresponding CRC bits; and

encoding the content with said scrambled or encrypted message, to yield digitally watermarked content;

wherein the encoding act is performed by a combination of hardware and software.