Synchronization of media signals

• US 7,840,005 B2
• Filed: 01/20/2005
• Issued: 11/23/2010
• Est. Priority Date: 01/22/2002
• Status: Expired due to Fees

• Current Assignee: Digimarc Corporation
• Original Assignee: Digimarc Corporation
• Inventors: Delp, Edward J., Lin, Eugene T.
• Primary Examiner(s): Smithers; Matthew B
• Assistant Examiner(s): Gelagay; Shewaye
• Application Number:
  US11/040,168
• Publication Number:
  US 20050185819A1
• Time in Patent Office: 2,133 Days
• Field of Search: 380/201
• US Class Current: 380/201
• CPC Class Codes: G06T 1/0028 Adaptive watermarking, e.g. Human Visual System [HVS]-based watermarking
• CPC Class Codes: G06T 1/0064 Geometric transfor invariant watermarking, e.g. affine transform invariant
• CPC Class Codes: G06T 2201/0051 Embedding of the watermark in the spatial domain
• CPC Class Codes: G06T 2201/0052 Embedding of the watermark in the frequency domain
• CPC Class Codes: H04N 19/467 characterised by the embedded information being invisible, e.g. watermarking
• CPC Class Codes: H04N 21/242 Synchronization processes, e.g. processing of PCR [Program Clock References] arrangements for synchronising broadcast or distribution via plural systems in broadcast distribution systems H04H20/18
• CPC Class Codes: H04N 21/426 Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• CPC Class Codes: H04N 21/4302 Content synchronisation processes, e.g. decoder synchronisation
• CPC Class Codes: H04N 21/44008 involving operations for analysing video streams, e.g. detecting features or characteristics in the video stream arrangements characterised by components specially adapted for monitoring, identification or recognition of video in broadcast systems H04H60/59
• 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
• CPC Class Codes: H04N 5/04 Synchronising for television systems using pulse code modulation H04N7/56

Abstract

A method for synchronization of a media signal computes features of the media signal and determines redundancy of the features to establish synchronization. The synchronization method is adapted for both temporal and spatial synchronization. For spatial synchronization, spatial redundancy is used to detect geometric distortion of a signal using an autocorrelation method to detect peaks caused by the redundancy of features of the signal. These peaks are then analyzed with a histogram method to detect rotation and scaling of the host media signal. The spatial synchronization process is applied for both intra-coded frames of video (I-frames) as well as still images.

Claims

1. A method for synchronization of a host media signal, the method comprising:

using one or more programmed processors to perform acts of;

detecting peaks due to redundancy of features in a host media signal;

wherein the redundancy is controlled via a state machine that repeats a portion of a watermark structure, and varies another portion of the watermark structure over a coordinate system of the host media signal;

analyzing the peaks to derive estimates of geometric or temporal distortion of the host media signal;

computing a histogram of the estimated geometric or temporal distortion parameters; and

from the histogram, computing a geometric or temporal distortion of the host media signal.

2. The method of claim 1 wherein the geometric distortion parameters represent rotation angles.

3. The method of claim 1 wherein the geometric distortion parameter represent spatial scaling.

4. The method of claim 1 wherein the redundancy comprises spatial redundancy.

5. The method of claim 1 wherein the redundancy comprises temporal redundancy.

6. An apparatus comprising:

a memory for storing a host media signal;

a programmed multipurpose electronic processor or configured electronic circuitry in communication with the memory for detecting peaks due to redundancy of features in a host media signal;

for analyzing the peaks to derive estimates of geometric or temporal distortion of the host media signal;

for computing a histogram of the estimated geometric or temporal distortion parameters; and

for computing a geometric or temporal distortion of the host media signal from the histogram;

wherein the redundancy is controlled via a state machine that repeats a portion of a watermark structure, and varies another portion of the watermark structure over a coordinate system of the host media signal.

7. The apparatus of claim 6 wherein the geometric distortion parameters represent rotation angles.

8. The apparatus of claim 6 wherein the geometric distortion parameter represent spatial scaling.

9. A non-transitory computer readable medium on which is stored instructions, which, when executed by a processor, perform a method for synchronization of a host media signal, the method comprising:

detecting peaks due to redundancy of features in a host media signal;

wherein the redundancy is controlled via a state machine that repeats a portion of a watermark structure, and varies another portion of the watermark structure over a coordinate system of the host media signal;

analyzing the peaks to derive estimates of geometric or temporal distortion of the host media signal;

computing a histogram of the estimated geometric or temporal distortion parameters; and

from the histogram, computing a geometric or temporal distortion of the host media signal.