Synchronization of media signals
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.
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.