Steganography methods employing embedded calibration data
DC CAFCFirst Claim
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1. A method of steganographic encoding characterized by:
- processing a sampled input signal to produce an output signal having an information signal embedded therein, the sampled input signal corresponding to a two dimensional visual image, each sample of said input signal having a value, the encoding including changing at least certain of said input signal sample values to encode the information signal therein,encoding a calibration signal in the output signal together with said information signal, said calibration signal including data corresponding to a predetermined geometrical pattern, said calibration signal having known properties facilitating identification thereof by a recipient of the encoded signal, said encoded calibration signal being substantially imperceptible to a human viewer of the encoded visual image, said predetermined geometrical pattern including a plurality of rotationally symmetric component pattern elements,wherein there exists at least first and second rotational orientations of said image for which at least one of said component pattern elements, as embedded in the output signal, has the same orientation.
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Abstract
An identification code signal is impressed on a carrier to be identified (such as an electronic data signal or a physical medium) in a manner that permits the identification signal later to be discerned and the carrier thereby identified. The method and apparatus are characterized by robustness despite degradation of the encoded carrier, and by permeation of the identification signal throughout the carrier.
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Citations
57 Claims
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1. A method of steganographic encoding characterized by:
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processing a sampled input signal to produce an output signal having an information signal embedded therein, the sampled input signal corresponding to a two dimensional visual image, each sample of said input signal having a value, the encoding including changing at least certain of said input signal sample values to encode the information signal therein, encoding a calibration signal in the output signal together with said information signal, said calibration signal including data corresponding to a predetermined geometrical pattern, said calibration signal having known properties facilitating identification thereof by a recipient of the encoded signal, said encoded calibration signal being substantially imperceptible to a human viewer of the encoded visual image, said predetermined geometrical pattern including a plurality of rotationally symmetric component pattern elements, wherein there exists at least first and second rotational orientations of said image for which at least one of said component pattern elements, as embedded in the output signal, has the same orientation. - View Dependent Claims (2, 3, 4, 5, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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6. The method of claim 1in which the calibration signal comprises a plurality of data elements, each of said data elements also being included in said information signal, wherein said calibration signal is concatenated with the information signal and embedded therewith in the input signal.
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22. A method of steganographic encoding characterized by:
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processing a sampled input signal to produce an output signal having an information signal embedded therein, the sampled input signal corresponding to an audio signal or a visual image, each sample of said input signal having a value, the encoding including changing at least certain of said input signal sample values to encode the information signal therein, encoding a calibration signal in the output signal together with said information signal, said calibration signal having known properties facilitating identification thereof by a recipient of the encoded signal, said encoded calibration signal being substantially imperceptible to a human listener of the encoded audio signal or viewer of the encoded visual image, said calibration signal enabling the information signal to be recovered from a corrupted output signal without reference to the input signal, wherein the corrupted output signal is the output signal corrupted by a process selected from a group consisting of;
misregistration of the output signal, and scaling of the output signal. - View Dependent Claims (23, 24, 25)
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26. A method of steganographic decoding characterized by:
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processing an encoded input signal to recover an information signal embedded therein, the encoded input signal corresponding to an audio signal or a visual image whose representation by said input signal has been altered in slight respects to encode the information signal therein, a calibration signal being present within the encoded input signal, said calibration signal within the encoded input signal being substantially imperceptible to a human listener of the encoded audio signal or viewer of the encoded visual image, said calibration signal having one or more known properties facilitating identification thereof during decoding of the encoded input signal, the method including identifying the calibration signal within said encoded input signal, and using data obtained thereby to aid in steganographically recovering the information signal from the encoded input signal, wherein the encoded input signal has been corrupted since being encoded, said corruption including a process selected from the group consisting of;
misregistration of the encoded input signal, and scaling of the encoded input signal,the method further including using said data to compensate for said corruption, wherein the information signal can nonetheless be recovered from the encoded input signal notwithstanding said corruption. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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45. A method of steganographic decoding characterized by:
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processing an encoded input signal to recover an information signal embedded therein, the encoded input signal corresponding to a two dimensional visual image whose representation by said input signal has been altered in slight respects to encode the information signal therein, a calibration signal being present within the encoded input signal, said calibration signal including data corresponding to a predetermined geometrical pattern, said calibration signal within the encoded input signal being substantially imperceptible to a human listener of the encoded audio signal or viewer of the encoded visual image, said calibration signal having one or more known properties facilitating identification thereof during decoding of the encoded input signal, the method including identifying the calibration signal within said encoded input signal, and using data obtained thereby to aid in steganographically recovering the information signal from the encoded input signal, said predetermined geometrical pattern including a plurality of rotationally symmetric component pattern elements, wherein there exists at least first and second rotational orientations of said image for which at least one of said component elements, as embedded in the encoded input signal, has the same orientation. - View Dependent Claims (46)
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47. A method of steganographic encoding characterized by:
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processing a sampled input signal to produce an encoded output signal having an information signal embedded therein, the sampled input signal and the encoded output signal both corresponding to a visual image, each sample of said input signal having a value, the encoding including changing at least certain of said input signal sample values to encode the information signal therein, encoding a calibration signal in the output signal together with said information signal, said calibration signal having known properties facilitating identification thereof by a recipient of the encoded signal, said encoded calibration signal being substantially imperceptible to a human viewer of the encoded visual image, said calibration signal enabling the information signal to be recovered from a corrupted output signal without reference to the input signal, wherein the corrupted output signal is the output signal corrupted by rotation of the image corresponding thereto from an original orientation.
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48. A method of steganographic decoding characterized by:
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processing an encoded input signal to recover an information signal embedded therein, the encoded input signal corresponding to a visual image whose representation by said signal has been altered in slight respects to encode the information signal therein, a calibration signal being present within the encoded input signal, said calibration signal within the encoded input signal being substantially imperceptible to a human viewer of the encoded visual image, said calibration signal having one or more known properties facilitating identification thereof during decoding of the encoded input signal, the method including identifying the calibration signal within said encoded input signal, and using data obtained thereby to aid in steganographically recovering the information signal from the encoded input signal, wherein the encoded input signal has been corrupted since being encoded, said corruption comprising rotation of the image corresponding to said encoded input signal from an original orientation, the method further including using said data to compensate for said corruption, wherein the information signal can nonetheless be recovered from the encoded input signal notwithstanding said corruption.
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49. In a method of steganographic image processing that includes processing a two dimensional input image to steganographically encode an information signal therein, thereby yielding a two dimensional output image, and thereafter decoding the output image to steganographically discern the information signal therein, an improvement comprising:
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providing data corresponding to at least one geometrical pattern, said pattern having at least one axis of symmetry; transforming said data to another domain; filtering the transformed data; inverse transforming said filtered data; and embedding said inverse transformed data in the output image, wherein said filtering in the transformed domain disperses the geometrical pattern through the output image, reducing its visibility. - View Dependent Claims (50, 51, 52, 53, 54, 55, 56, 57)
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Specification