Computing distortion of media signals using embedded data with repetitive structure and log-polar mapping
First Claim
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1. A computing apparatus to determine distortion of a signal with embedded data, said apparatus comprising:
- electronic processing circuitry; and
memory, said memory comprising instructions for processing by said electronic processing circuitry, the instructions comprising instructions to;
transform the signal into a transform domain to produce peaks due to a repetitive structure of the embedded data in the signal;
perform a mapping of the transformed signal to convert distortion of the embedded data into a shift; and
perform a correlation of the mapped signal with a signal representing an expected pattern of peaks associated with the repetitive structure of the embedded data signal, wherein the correlation detects the shift, and the shift provides a measure of the distortion of the signal.
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Abstract
A digital watermark detection method uses a matched filtering technique on a log polar re-mapping of a watermarked signal to detect peaks associated with a repetitive structure of a watermark.
39 Citations
22 Claims
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1. A computing apparatus to determine distortion of a signal with embedded data, said apparatus comprising:
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electronic processing circuitry; and memory, said memory comprising instructions for processing by said electronic processing circuitry, the instructions comprising instructions to; transform the signal into a transform domain to produce peaks due to a repetitive structure of the embedded data in the signal; perform a mapping of the transformed signal to convert distortion of the embedded data into a shift; and perform a correlation of the mapped signal with a signal representing an expected pattern of peaks associated with the repetitive structure of the embedded data signal, wherein the correlation detects the shift, and the shift provides a measure of the distortion of the signal. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of detecting a digital watermark in a signal comprising:
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utilizing at least a processor or electronic processing circuitry, transforming the signal into a transform domain to emphasize a repetitive structure of the digital watermark in the signal; performing a mapping of the transformed signal to convert geometric distortion of the digital watermark into a shift; and utilizing at least a processor or electronic processing circuitry, performing a detection of the digital watermark in the mapped signal using an expected pattern corresponding to data embedded in the digital watermark, wherein prior to said act of performing, said method includes combining additional bits with the signal to help provide a linear correlation upon execution of a correlation process. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 21, 22)
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16. A method of detecting a digital watermark in an image signal comprising:
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utilizing at least a processor or electronic processing circuitry, computing the autocorrelation of the image signal to emphasize a repetitive structure of the digital watermark in the signal; utilizing at least a processor or electronic processing circuitry, performing a log polar mapping of the transformed signal to convert rotation and spatial scaling of the digital watermark into shifts; and utilizing at least a processor or electronic processing circuitry, performing a detection of the digital watermark in the log polar mapped signal using a pattern corresponding to data embedded in the digital watermark, said act of performing a detection of the digital watermark utilizes the shifts, the shifts being determined with a Phase-Only-Matched filter. - View Dependent Claims (17, 18, 19, 20)
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Specification